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BackgroundCertain infectious agents are recognised causes of cancer and potentially other chronic diseases. Identifying associations and understanding pathological mechanisms involving infectious agents and subsequent chronic disease risk will be possible through measuring exposure to multiple infectious agents in large-scale prospective cohorts such as UK Biobank.MethodsFollowing expert consensus we designed a Multiplex Serology platform capable of simultaneously measuring quantitative antibody responses against 45 antigens from 20 infectious agents implicated in non-communicable diseases, including human herpes, hepatitis, polyoma, papilloma, and retroviruses, as well asChlamydia trachomatis, Helicobacter pyloriandToxoplasma gondii. This panel was assayed in a random subset of UK Biobank participants (n=9,695) to test associations between infectious agents and recognised demographic and genetic risk factors and disease outcomes.FindingsSeroprevalence estimates for each infectious agent were consistent with those expected from the literature. The data confirmed epidemiological associations of infectious agent antibody responses with sociodemographic characteristics (e.g. lifetime sexual partners withC, trachomatis;P=1·8×10−149), genetic variants (e.g. rs6927022 with Epstein-Barr virus (EBV) EBNA1 antibodies,P=9·5×10−91) and disease outcomes including human papillomavirus-16 seropositivity and cervical intraepithelial neoplasia (odds ratio 2·28, 95% confidence interval 1·38-3·63), and quantitative EBV viral capsid antigen responses and multiple sclerosis through genetic correlation (MHC rG=0·30,P=0·01).InterpretationThis dataset, intended as a pilot study to demonstrate applicability of Multiplex Serology in epidemiological studies, is itself one of the largest studies to date covering diverse infectious agents in a prospective UK cohort including those traditionally under-represented in population cohorts such as human immunodeficiency virus-1 andC. trachomatis. Our results emphasise the validity of our Multiplex Serology approach in large-scale epidemiological studies opening up opportunities for improving our understanding of host-pathogen-disease relationships. These data are available to researchers interested in examining the relationship between infectious agents and human health.

Brucellosis is a chronic bacterial infection that can infect a variety of animal species and humans. The disease has been studied in many parts of the world including Pakistan, however, caprine brucellosis has not been well reported and very few studies are published at the national level. This study was conducted to investigate the seroprevalence of brucellosis in goat and household animal keepers of district Swat Pakistan. A total of 235 blood samples were collected from goats and 53 blood samples from animal keepers following the standard protocols. All the serum samples were analyzed by the Rose Bengal Plate Test (RBPT) and Serum Plate Agglutination Test (SPAT) for the detection of anti-brucella antibodies. All the goat serum samples were also subjected to Enzyme-Linked Immunosorbent Assay (ELISA) for the comparison of two commonly used serological tests. The overall seroprevalence of brucellosis in the goat population of district Swat was recorded as 13.61% and 16.17% while in the human population it was recorded as 3.77% and 5.66% by RBPT and SPAT respectively. A significant correlation was found between abortion and seropositivity of brucellosis in goats with a p˂0.05. By comparing RBPT and SPAT considering ELISA as a gold standard, the SPAT test showed a greater sensitivity than RBPT recorded as 82% and 80 % by SPAT and RBPT respectively. It is concluded that brucellosis is prevailing in both the goat as well as in animal keepers of district Swat. Screening of animals and awareness of the general population through mass media is recommended.

Background & Aims Helicobacter pylori infection is the primary known risk factor for gastric cancer. Despite the global decline in H. pylori prevalence, this infection remains a major public health concern in developing areas, including Latin America. Our study aimed to determine H. pylori seroprevalence and identified its determinants among Hispanics/Latinos living in the United States (U.S.). Methods The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) is a population-based sample of self-identified Hispanics/Latinos (n = 16,144) in four U.S. communities, aged 18 to 74 years, recruited from randomly selected households using a stratified two-stage area probability sample design based on sampling households within sampled census block groups weighted for differential response rates. Anti-H. pylori immunoglobulin G antibodies were measured by an enzyme-linked immunosorbent assay using plasma samples. We calculated adjusted seroprevalence (i.e., predicted margins) from multivariable logistic regression models. Results The overall weighted H. pylori seroprevalence was 57% among HCHS/SOL participants, with 38% and 62% seropositivity among U.S.-born and non-U.S.-born individuals, respectively. Age-adjusted prevalence varied by self-reported Hispanic/Latino background, ranging from 47% in Puerto Rican to 72% in Central American backgrounds. Adjusted H. pylori seroprevalence was higher in the following groups: older age, male sex, lower education, non-U.S. born status, smoking, greater number of missing teeth, fewer doctor visits, lower ferritin level, and hepatitis A seropositivity. Conclusions H. pylori seroprevalence in Hispanics/Latinos remains high and differed significantly by Hispanic/Latino background. H. pylori seropositivity is strongly associated with poor socioeconomic conditions. These findings highlight the ongoing importance of this bacterial infection in the U.S.

Background The detection of islet autoantibodies is essential for the accurate classification and diagnosis of diabetes mellitus (DM). The islet autoantibody distribution varies by age. However, screening strategies for DM patients with different onset ages remain lacking. Methods This cross-sectional study included 17 536 DM patients from 46 medical centers across China. The seroprevalence of glutamic acid decarboxylase autoantibody (GADA), insulinoma-associated-2 autoantibody (IA-2A), zinc transporter 8 autoantibody (ZnT8A) and insulin autoantibody (IAA) was determined in younger and older patients with type 1 DM (T1DM) (n=287 and 285, respectively), younger and older patients with latent autoimmune diabetes (LAD) (n=140 and 121, respectively), and younger and older patients with type 2 DM (T2DM) (n=200 in each group). Results The cutoff age between younger and older patients was 35 years using restricted cubic spline method (n = 17 536, adjusted R2 = 0.97, residual standard error = 1.32; P < 0.001). The seroprevalence rates of four islet autoantibodies were higher in patients aged 15-35 years than in those ≥ 35 years (GADA: 17% vs. 5.6%, IA-2A: 8.5% vs. 1.3%, ZnT8A: 6.3% vs. 2.3%, IAA: 2.2% vs. 1.0%). The prevalence of ZnT8A was higher in LAD patients than in T1DM patients, especially in older LAD patients. The results indicated that ZnT8A detection can increase the detection rate of older LAD patients from 70.2% (based on GADA detection alone) to 91.7%. Conclusions In patients stratified according to the cutoff age of 35 years, the optimal detection sequence should be GADA, IA-2A, and ZnT8A in younger patients and GADA, ZnT8A, and IA-2A in older patients, so as to reduce the screening cost while improving the detection rate. Particularly, the ZnT8A test is recommended in older patients to avoid a missed LAD diagnosis.

OBJECTIVES Since 1991 hepatitis B vaccination has been mandatory for all newborns in Italy. The aim of the study was to verify the long-term seroprevalence and the efficacy of hepatitis B vaccination in medical students of the University of Siena. MATERIAL AND METHODS A cross-sectional observational study was conducted on a population of 850 medical students of the University of Siena (322 males and 528 females, mean age: 23 years) by obtaining from the medical reports the serological analysis data for the total anti-hepatitis B antibodies (HBsAb) and information on hepatitis B vaccination (number of vaccine doses, age at the first vaccination, time since the final vaccination dose, country of origin). Raw odds ratios (ORs) and 95% confidence intervals (CIs) were initially calculated to evaluate the association between 2 variables. The adjusted ORs were then calculated using a multivariate logistic regression model to study the association between the variables and the possible confounding factors. RESULTS Overall, 593 students (69.76%) were immunized against hepatitis B, while 257 (30.24%) had HBsAb antibody titer

Background Gastric acid-suppressive therapy has been suggested to increase the risk for intestinal carriage of MDR Enterobacterales, but there is scarce community-based evidence substantiating this risk. Objectives To investigate if acid-suppressant use is associated with a risk of intestinal carriage of ESBL and carbapenemase-producing Enterobacterales (ESBL-E) in the open population, and to assess possible modifying factors. Methods Within the framework of a nationwide seroprevalence study, we identified a population-based cross-sectional cohort comprising 2746 adults (≥18 years), who provided stool specimens between February 2016 and June 2017. Specimens were tested by phenotypic assays and confirmatory genotype analysis to detect carriage of ESBL-E. Covariate data were extracted from self-administered questionnaires. ORs and 95% CIs were estimated using multivariable multilevel logistic regression, controlling for confounders informed by directed acyclic graphs. Results Among 2746 participants, 316 (11.5%) used acid suppressants; the prevalence of ESBL-E carriage was 7.4% (95% CI, 6.1%–8.6%). Current use of acid suppressants was not associated with ESBL-E carriage (adjusted OR [aOR], 1.05; 95% CI, 0.64–1.74); lifestyle and comorbidity did not modify this association. A higher BMI (≥25 kg/m2) (aOR, 1.42 [95% CI, 1.02–1.98]), non-Western ethnic origin (aOR, 1.96 [95% CI, 1.34–2.87]), travel to Eastern-Mediterranean, Western-Pacific or South-East Asia regions (aOR, 3.16 [95% CI, 1.71–5.83]) were associated with ESBL-E carriage. Sensitivity analyses confirmed these results; spline analysis supported a BMI-associated risk. Conclusions In this open population study, current use of acid suppressants was not associated with ESBL-E carriage. Travel to high-endemic regions and non-Western ethnicity were confirmed as risk factors, while a higher BMI emerged as a potential new risk for ESBL-E carriage.

Background Seroprevalence studies of coronavirus disease 2019 (COVID-19) cases, including asymptomatic and past infections, are important to estimate the scale of the disease outbreak and to establish quarantine measures. We evaluated the clinical performance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays available in Korea for use in seroprevalence studies. Methods The sensitivity, specificity, cross-reactivity, and interference of five SARS-CoV-2 antibody assays were evaluated using the following: 398 serum samples from confirmed COVID-19 patients, 510 negative control samples from before 2018 (pre-pandemic), 163 serum samples from patients with SARS, Middle East respiratory syndrome (MERS), and other viral infections, and five samples for the interference study. Results The sensitivities of the five assays ranged from 92.2% to 98%, and their specificities, including cross-reactivity and interference, ranged from 97.5% to 100%. The agreement rates were excellent (kappa >0.9). Adjustment of the cutoff values could be considered through ROC curve analysis. The positive predictive values of the individual assays varied from 3.5% to 100% at a 0.1% prevalence but were as high as ≥95% when two assays were combined. Conclusions The prevalence of COVID-19 in Korea is considered to be exceptionally low at present; thus, we recommend using a combination of two or more SARS-CoV-2 antibody assays rather than a single assay. These results could help select SARS-CoV-2 antibody assays for COVID-19 seroprevalence studies in Korea.

Purpose The present study was undertaken with the objective to study the common etiology of Viral Haemorrhagic Fever (VHF) among patients attending tertiary health care centre in NE India and also to study the clinico-demographic profile of such patients. The agents of VHF included in the study were dengue, chikungunya and Crimean Congo haemorrhagic fever (CCHF) virus. The inclusion of CCHF was based on evidence of seroprevalence in livestock (bovine, sheep and goat) in various North Eastern states. Materials and methods Serum samples were collected from 51 suspected VHF patients. MAC-ELISA was done to detect dengue and chikungunya specific IgM antibody. The samples were also tested by real-time RT-PCR for detection of dengue, chikungunya and CCHF specific nucleic acid. The laboratory and clinico-demographic profile of these patients were noted in detail. Results Serum samples of 16 of 51 suspected cases were confirmed to be suffering from VHF. Among these confirmed cases, 12 were diagnosed with dengue haemorrhagic fever, one was diagnosed with chikungunya and three were diagnosed with dengue-chikungunya co-infection. Based on severity, DHF was further classified into- DHF I- (4,26.6%), DHF II (6,40%), DHF III (3,20%) and DHF IV (2,13.3%). There was no CCHFV infection detected in our study. Retro-orbital pain (P ​= ​0.02) and haematocrit level (P ​= ​0.03) were found to be statistically significant. Conclusions This study reiterates the fact that CCHF virus infection is still probably absent in human population of NE India and haemorrhagic symptoms, though rare maybe one of the atypical manifestations of chikungunya infection.

Objectives Outbreaks of measles have been reported in Europe, including in countries that have previously eliminated endemic transmission. Seroprevalence data are needed to predict the outbreak cycles. No published measles seroprevalence data is available from Estonia and only few from Eastern Europe have been published. The objective of this study is to describe measles seropositivity in Estonia. Methods Between February and June 2019, all 1300 health care workers of an academic hospital were invited. From the 738 (56.7%) respondent (90% female, mean age (SD) of 47 (12) years), IgG measles titre were measured. Results Among the participants, 71% were seropositive. When data were further analysed according to vaccination birth cohorts, the oldest cohort (born before vaccination was introduced in 1964) had the highest seropositivity proportion (91%), vs. other birth cohorts with various types of vaccines (around 60%). Conclusions Measles seropositivity is lower than the threshold level to interrupt endemic virus transmission. No difference in seroprevalence among participants who received various types of measles vaccines.

Hepatitis E virus (HEV) is an RNA virus causing hepatitis E disease. The virus is of one serotype but has diverse genotypes infecting both humans and animals. Based on evidence from seroprevalence studies, about 2 billion people are estimated to have been infected with HEV globally. HEV, therefore, poses a significant public health and economic challenge worldwide. HEV was discovered in the 1980s and was traced back to the 1955 – 1956 outbreak of hepatitis that occurred in India. Subsequently, several HEV epidemics involving thousands of individuals have occurred nearly annually in different countries in Asia and Africa. Initially, the virus was thought to be only enterically transmitted, and endemic in developing countries. Due to the environmental hygiene and sanitation challenges in those parts of the world. However, recent studies have suggested otherwise with the report of autochthonous cases in industrialised countries with no history of travel to the so-called endemic countries. Thus, suggesting that HEV has a global distribution with endemicity in both developing and industrialised nations. Studies have also revealed that HEV has multiple risk factors, and modes of transmission as well as zoonotic potentials. Additionally, recent findings have shown that HEV leads to severe disease, particularly among pregnant women. In contrast to the previous narration of a strictly mild and self-limiting infection. Studies have likewise demonstrated chronic HEV infection among immunocompromised persons. Consequent to these recent discoveries, this pathogen is considered a re – emerging virus, particularly in the developed nations. However, despite the growing public health challenges of this pathogen, the burden is still underestimated. The underestimation is often attributed to poor awareness among clinicians and a lack of routine checks for the disease in the hospitals. Thus, leading to misdiagnosis and underdiagnosis. Hence, this review provides a concise overview of epidemiology, diagnosis, and prevention of hepatitis E.

Background & Objective: The prevalence of COVID-19 and its severity have been observed to be on a lower level in underdeveloped countries with poorer standards of hygiene. This disparity may be attributed to the higher seroprevalence of other viral diseases which can result in the presence of antibodies protective against COVID-19. Two of the widespread diseases in such countries are infection to hepatitis A and E viruses (HAV and HEV). In the present study, we explored the relationship between the level of antibodies against these viruses and the susceptibility to COVID-19. Methods: Ninety patients were studied in two groups of controls and cases each consisting 45 individuals. The cases were patients with the clinical symptoms of COVID-19 and positive RT-PCR test results. The controls were individuals referred to the respiratory triage of Imam Khomeini Hospital Complex and were not demonstrating relevant clinical symptoms of COVID-19 and their RT-PCR test results were negative. Levels of HAV and HEV antibodies were measured and compared in these two groups. Results: The median of HAV antibody level was 13.6 (IQR=11.5-16.9) and 13.2 (IQR =10.7-14.7) in cases and controls, respectively, showing no statistically significant difference (P = 0.1). Likewise, the median of HEV antibody level was 6.7 (IQR=5.3-7.1) and 7.1 (IQR=6.3-7.5) in cases and controls, respectively, which again showed no statistically significant difference (P=0.41). Conclusion: The present study was carried out in a region with a relatively high prevalence of HAV and HEV infections. Contrary to our expectations, no statistically significant relationship was observed between the levels of antibodies against these viruses and the susceptibility to COVID-19. Further studies with larger sample sizes and in other countries are needed to come to a definite conclusion.

Objective Our objective was to assess within-herd seroprevalence of Anaplasma marginale antibodies across 12 Florida beef cattle herds and compare with statewide seroprevalence. Materials and Methods Twelve surveyed herds ranged in size from 160 to 456 adult Bos taurus–Bos indicus cattle. Statewide A. marginale seroprevalence relied on blood samples obtained at slaughter from 201 Florida cattle. Screening relied on competitive ELISA. Results and Discussion Before serology, an outbreak of anaplasmosis resulted in increased mortality (up to 17.8%) and abortions in several herds. Up to 29.2% of cows aborted late in gestation in 2 herds that included many cattle introduced from Texas. Among 1,085 cattle tested in the 12 herds, seroprevalence of A. marginale varied from 2.6 to 85%, with an overall seropositive rate of 50.3%. Cattle in open herds were 6.23 (95% CI: 4.26–9.17) times more likely to experience mortality and 3.10 (95% CI: 2.39–3.98) times more likely to abort than animals in closed herds. Average mortality (12%) and abortion (16.3%) among open herds were significantly (P Implications and Applications This survey provides estimates of seropositivity among Florida cattle and reports the absence of uniform herd immunity in an area considered endemic for bovine anaplasmosis. These data highlight unrestricted cattle movement and environmental conditions that favor vector-borne disease transmission as risk factors for disease outbreaks even in regions that are considered endemic for bovine anaplasmosis.

Toxoplasma gondii is a worldwide occurring apicomplexan parasite. Due to its high seroprevalence in livestock as well as in game animals, T. gondii is an important food-borne pathogen and can have significant health implications for humans as well as for pets. This article describes the prevalence of T. gondii in free-ranging macropods hunted for consumption. All hunted macropod species (commercial as well as non-commercial hunt) show a positive seroprevalence for T. gondii. This seroprevalence is influenced by various factors, such as sex or habitat. Furthermore, the parasite shows a high level of genetic variability in macropods. Genetically variable strains have already caused outbreaks of toxoplasmosis in the past (Canada and the US). These were attributed to undercooked game meat like venison. Despite this risk, neither Australia nor New Zealand currently have food safety checks against foodborne pathogens. These conditions scan pose a significant health risk to the population. Especially, since cases of toxoplasmosis have already been successfully traced back to insufficiently cooked kangaroo meat in the past.

Summary Background SARS-CoV-2 has spread substantially within India over multiple waves of the ongoing COVID-19 pandemic. However, the risk factors and disease burden associated with COVID-19 in India remain poorly understood. We aimed to assess predictors of infection and mortality within an active surveillance study, and to probe the completeness of case and mortality surveillance. Methods In this prospective, active surveillance study, we used data collected under expanded programmatic surveillance testing for SARS-CoV-2 in the district of Madurai, Tamil Nadu, India (population of 3 266 000 individuals). Prospective testing via RT-PCR was done in individuals with fever or acute respiratory symptoms as well as returning travellers, frontline workers, contacts of laboratory-confirmed COVID-19 cases, residents of containment zones, patients undergoing medical procedures, and other risk groups. Standardised data collection on symptoms and chronic comorbid conditions was done as part of routine intake. Additionally, seroprevalence of anti-SARS-CoV-2 immunoglobulin G was assessed via a cross-sectional survey recruiting adults across 38 clusters within Madurai District from Oct 19, 2020, to Nov 5, 2020. We estimated adjusted odds ratios (aORs) for positive RT-PCR results comparing individuals by age, sex, comorbid conditions, and aspects of clinical presentation. We estimated case-fatality ratios (CFRs) over the 30-day period following RT-PCR testing stratified by the same variables, and adjusted hazard ratios (aHRs) for death associated with age, sex, and comorbidity. We estimated infection-fatality ratios (IFRs) on the basis of age-specific seroprevalence. Results Between May 20, 2020, and Oct 31, 2020, 13·5 diagnostic tests were done per 100 inhabitants within Madurai, as compared to 7·9 tests per 100 inhabitants throughout India. From a total of 440 253 RT-PCR tests, 15 781 (3·6%) SARS-CoV-2 infections were identified, with 8720 (5·4%) of 160 273 being positive among individuals with symptoms, and 7061 (2·5%) of 279 980 being positive among individuals without symptoms, at the time of presentation. Estimated aORs for symptomatic RT-PCR-confirmed infection increased continuously by a factor of 4·3 from ages 0–4 years to 80 years or older. By contrast, risk of asymptomatic RT-PCR-confirmed infection did not differ across ages 0–44 years, and thereafter increased by a factor of 1·6 between ages 45–49 years and 80 years or older. Seroprevalence was 40·1% (95% CI 35·8–44·6) at age 15 years or older by the end of the study period, indicating that RT-PCR clinical testing and surveillance testing identified only 1·4% (1·3–1·6%) of all infections in this age group. Among RT-PCR-confirmed cases, older age, male sex, and history of cancer, diabetes, other endocrine disorders, hypertension, other chronic circulatory disorders, respiratory disorders, and chronic kidney disease were each associated with elevated risk of mortality. The CFR among RT-PCR-confirmed cases was 2·4% (2·2–2·6); after age standardisation. At age 15 years or older, the IFR based on reported deaths was 0·043% (0·039–0·049), with reported deaths being only 11·0% (8·2–14·5) of the expected count. Interpretation In a large-scale SARS-CoV-2 surveillance programme in Madurai, India, we identified equal risk of asymptomatic infection among children, teenagers, and working-age adults, and increasing risk of infection and death associated with older age and comorbidities. Establishing whether surveillance practices or differences in infection severity account for gaps between observed and expected mortality is of crucial importance to establishing the burden of COVID-19 in India. Funding The Bill & Melinda Gates Foundation, the National Science Foundation, and the National Institute of General Medical Sciences. Translation For the Hindi translation of the abstract see Supplementary Materials section.

Dengue fever is regarded as an important neglected Arboviral disease worldwide. This study aimed at investigating the prevalence of dengue IgM seroprevalence, malaria parasitaemia and some haematological parameters of HIV infected individuals attending Chukwuemeka Odumegwu Ojukwu Teaching Hospital Amaku, Awka, Nigeria. A cross sectional study consisting of 188 participants was performed. The demographic data and possible risks factors of the subjects were obtained using well-structured questionnaire. Dengue virus IgM was analysed using Enzyme-linked immunosorbent assay (ELISA) techniques, Malaria parasitaemia was determined using microscopy technique while some haematological parameters were evaluated using heamatology auto analyser (PE-6800 fully auto heamatology analyser procan). Statistical analysis was performed using the statistical package for social (spss) version 25. The results of this study showed that the prevalence of Dengue virus was 20.2% while that of Malaria was 37.2%. The co-infection of Dengue virus IgM antibodies and Malaria parasitemia was 8.51%. Plasmodium falciparium was seen as the only specie of malaria parasite present in the study. The results of some haematogical parameters of the Dengue virus seropositive participants as compared with the Dengue virus seronegative participants were statistically significant with neutrophils (p = 0.035), mean cell hemoglobin concentration (MCHC = p

Background Acute febrile illnesses (AFIs), including dengue, scrub typhus and leptospirosis, cause significant morbidity and mortality in Southeast Asia. Serological surveillance can be used to investigate the force and distribution of infections. Dried blood spot (DBS) samples are an attractive alternative to serum because they are easier to collect and transport and require less cold storage. We conducted a pilot study to determine the feasibility of integrating serological surveillance for dengue, scrub typhus and leptospirosis into a population-representative lymphatic filariasis seroprevalence survey in Timor-Leste using DBSs. Methods A total of 272 DBSs were collected from healthy community participants. DBSs were analysed at the National Health Laboratory using commercially available enzyme-linked immunosorbent assays. To validate assays for DBSs, 20 anonymised serum samples of unknown serostatus were used to create dried serum spots (DSSs). These were analysed with optical densities compared with those of serum. Where low variance was observed (dengue assay) the published kit cut-offs for serum were applied to the analysis of DBSs. For the other assays (scrub typhus and leptospirosis), index values (IVs) were calculated and cut-offs were determined to be at 2 standard deviations (SDs) above the mean. Results Of the 272 samples analysed, 19 (7.0% [95% confidence interval {CI} 4.3 to 10.7]) were positive for dengue immunoglobulin G (IgG), 11 (4.0% [95% CI 2.1 to 7.1]) were positive for scrub typhus IgG and 16 (5.9% [95% CI 3.4 to 9.4%]) were positive for leptospira IgG. Conclusions While dengue seroprevalence was lower than in nearby countries, results represent the first evidence of scrub typhus and leptospirosis transmission in Timor-Leste. Integrated programmes of serological surveillance could greatly improve our understanding of infectious disease epidemiology in remote areas and would incur minimal additional fieldwork costs. However, when planning such studies, the choice of assays, their validation for DBSs and the laboratory infrastructure and technical expertise at the proposed location of analysis must be considered.

Objective Estimating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence is an important part of the public health approach to coronavirus disease 2019 (COVID-19) understanding and containment. This is particularly relevant to an obstetric population because of implications in the management of the pregnant host, care of the newborn, and disease progression within the community. Study design A cross-sectional seroprevalence study was performed in four Department of Health Palm Beach County clinics from June 29, 2020, to August 5, 2020. Samples were collected from asymptomatic antepartum and postpartum participants. A web-based surveillance system was used to identify subsequent antibody or polymerase chain reaction (PCR) testing encounters. Results A total of 163 of 618 subjects were seropositive (26.4%). Racial makeup was white 2.5%, black 19.0%, and Hispanic 78.5%. Positive serology was seen in 16.0, 35.6, and 30.1% of first, second, and third trimesters, respectively; 18.4% were positive postpartum. Only four patients voluntarily reported PCR positivity prior to antibody testing. Six home zip codes accounted for the majority (68.1%) of positive results. Thirty-two patients had repeat serology (65.6% positive and 34.4% negative). Of the 163 subjects, 65 underwent later PCR testing with 92% negative for SAR-CoV-2. Conclusion Almost one in four subjects had serologic evidence of previous SARS-CoV-2 infection. These very high seroprevalence rates have not been previously reported and highlight the concern for health disparities in the United States. Most were asymptomatic and without a history for SARS-CoV-2 exposure. There was a loss of seropositivity in a significant number of subjects, raising concern for risk of reinfection, inadequate transplacental antibody transfer, and subsequent limited passive protection to the newborn. These seroprevalence data will also allow for better newborn follow-up of unanticipated consequences of COVID-19 infection in pregnancy. Key points · SAR-CoV-2 seroprevalence is disproportionately high in this obstetric population. · The majority of subjects who tested positive for SAR-CoV-2 were asymptomatic for COVID-19 infection. · Estimating seroprevalence is an important public health approach to disease surveillance and understanding.

Background and Aim: Brucellosis is a zoonotic disease of high economic and public health importance in large and small ruminant populations worldwide. A cross-sectional study was conducted to determine the seroprevalence and risk factors of brucellosis in small ruminants in organized farms in the southern region of India. Materials and Methods: Farms exclusively rearing sheep and goats were selected based on the number of animals (small, medium, or large) and the location of the farm (urban, periurban, or rural). A total of 1499 serum samples; 1001 from sheeps and 498 from goats were sourced from six sheep and four goat farms and tested using Rose Bengal Plate and indirect Enzyme-Linked Immunosorbent Assay tests. Results: The apparent prevalence of brucellosis was higher in sheep (8.29%, 95% CI 6.7-10.1) than goats (5.82%, 95% CI 4.0-8.2). The true adjusted population level seroprevalence was also higher in sheep, at 7.7% (95% CI 6.0-9.6) than in goats, at 5.1% (95% CI 3.2-7.6). According to bivariate categorical analysis, six highly significant (p

Animal disease surveillance in limited-resource countries is challenging but critical in providing epidemiological information to inform disease prevention and control programmes. Despite multiple international agencies and partnerships supporting Lao PDR and Cambodia’s animal disease surveillance activities over many years, cost-effectiveness and sustainability remain significant constraints. Here we describe the development and implementation of national abattoir-based surveillance networks in Laos and central Cambodia consisting of an information exchange platform and sample collection and submission systems. The networks enhanced the national surveillance capacity and provided snapshot information of seroprevalence for selected One Health and high consequence veterinary pathogens, including Q fever, brucellosis, and Foot and Mouth Disease (FMD). Despite abattoir survey data revealing that the seroprevalence of Q fever and brucellosis was generally low, the true impact on public health for these diseases remains unclear due to low levels of awareness and diagnostic capacity. FMD antibodies derived from natural infection rather than vaccination were noted in greater than 40% of the animal sampled in both countries, which suggests significant underreporting of outbreak events. Such networks will continue to be refined to improve their cost-effectiveness and sustainability, including the introduction of a simple online application for reporting animal disease outbreaks as well as expanding to other relevant One Health pathogens and species.

Programs to eliminate trachoma as a public health problem use prevalence of the clinical sign trachomatous inflammation—follicular (TF) in 1- to 9-year-olds in endemic districts to make decisions to begin or end mass drug administration with azithromycin. Trachomatous inflammation—follicular is used as a proxy for transmission of ocular Chlamydia trachomatis infection. Long-term monitoring of previously endemic districts for recrudescence of ocular C. trachomatis infection would benefit from a simple blood test that could be integrated with other public health programs. In this study, we evaluated multiple tests to measure antibodies against the C. trachomatis antigen Pgp3—a multiplex bead assay (MBA), an ELISA, and two versions of a lateral flow assay (LFA)—in four districts of the Amhara region of Ethiopia with varying levels of TF. Seroprevalence and seroconversion rate (SCR) results were proportional to TF prevalence by district for most tests, with the notable exception of the LFA using colloidal gold as the developing reagent. Changing the test developing reagent to black latex improved agreement between serological measures and TF prevalence and in inter-rater agreement. Seroconversion rate estimates using data derived from the LFA-gold assay were inconsistent with the shape of the age-seroprevalence curve, which did not increase in older ages. These data revealed potential complications with using SCR that will need further evaluation. Data from MBA, ELISA, and LFA with the black test line showed good agreement with each other and proportionality to TF estimates, providing further data that serology has potential utility for trachoma surveillance.

Background Refugees in Malaysia, who are afflicted by poverty, conflict and poor health, are vulnerable to a range of zoonotic infections in the deprived environmental and social conditions under which they live. Exposure to infections such as leptospirosis, for which rodents are primary hosts, is of particular concern. Methods A wellness program was conducted to determine the presence of antibodies against Leptospira (seroprevalence) in 11 refugee community schools and centers in the Klang Valley, Malaysia. A total of 433 samples were assessed for IgG and IgM antibodies against Leptospira, using enzyme-linked immunosorbent assays (ELISA). Results Overall Leptospira seroprevalence was 24.7%, with 3.0% being seropositive for anti-Leptospira IgG and 21.7% for anti-Leptospira IgM. Factors significantly associated with overall Leptospira seroprevalence included: age, ethnicity, pet ownership, knowledge of disease and awareness of disease fatality. For IgM seroprevalence, significant risk factors included sex, ethnicity, eating habits with hands, pet ownership, the presence of rats, walking in bare feet and water recreation visits. Conclusions These findings highlight the need for improvements in health and well-being among the refugee community through disease awareness programs and provision of healthy behavior programs, particularly in hygiene and sanitation through community engagement activities.

Meseret Ayelign,1 Melak Aynalem,2 Nega Berhane3 1Department of Molecular Biology, Specialized Referral Hospital, University of Gondar, Gondar, Ethiopia; 2Department of Hematology and Immunohematology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Science, University of Gondar, Gondar, Ethiopia; 3Department of Biotechnology, College of Natural Sciences, University of Gondar, Gondar, EthiopiaCorrespondence: Melak AynalemDepartment of Hematology and Immunohematology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Science, University of Gondar, P.O. Box 196, Gondar, EthiopiaTel +251 912692619Email melak.aynalem1234@gmail.comBackground: Viral infections are the most common diseases. Of them, human immunodeficiency virus (HIV), hepatitis B viruses (HBV), and hepatitis C viruses (HCV) are common. When HBV or HCV becomes co-morbid with HIV, they lead to severe forms of a disease and rapid death.Objective: This study aimed to determine the seroprevalence and associated factors of HBV and HCV among HIV-positive study participants.Methods: A cross-sectional study was conducted among 81 individuals, and a non-randomized purposive sampling technique was used. From each study participant, sociodemographic and clinical data were gathered by using a pretested questionnaire and data collection sheet, respectively. Further, a venous blood sample was collected for viral load count, and HBV and HCV determination. To keep the quality of test results, commercially prepared quality control samples were used. The data were entered to EPI-Info version 7 and analyzed by using SPSS version 20. The descriptive data were summarized in percentages, median, and IQR. Logistic regression was analyzed to determine associated factors. To say the data were statistically significant, the p-values should be less than 0.05.Results: A total of 81 study participants were included. Of them, 56.8% (46/81) and 67.9% (55/81) were female and urban residents, respectively. The prevalence of hepatitis co-infection was 21% (95% CI: 17%, 23%). Further, the prevalence of HBV/HIV and HCV/HIV was 13.5% (95% CI: 10.5%, 16.5%) and 8.6% (95% CI: 5.6%, 11.6%), respectively. Wise use of highly active antiretroviral therapy (HAART) 0.01 (0.00, 0.213) was a preventive factor to hepatitis infection.Conclusion and Recommendation: The HBV and HCV co-infection among HIV-positive patients was a significant public health concern. Also, having wise use of HAART can reduce exposure to hepatitis co-infection. Therefore, clear strategies on hepatitis screening and wise use of HAART to HIV would be critical.Keywords: seroprevalence, HBV, HCV, HIV, Gondar, Ethiopia

Introduction: The effect of SARS-CoV-2 infection in patients with multiple sclerosis (MS) and the influence of disease-modifying therapies (DMT) for MS on COVID-19 are unknown. To date, patients with MS have not been shown to present greater risk of COVID-19 or more severe progression of the disease. Methods: We performed a descriptive study of patients with MS presenting SARS-CoV-2 infection diagnosed with PCR. We analysed demographic, clinical, laboratory, and treatment variables in our sample. Presence of antibodies against the virus was also determined. Results: Relapsing-remitting MS (RRMS) was the most frequent form of MS in our sample. Prognosis was unfavourable in 10.2% of patients, and was associated with older age and higher scores on the Expanded Disability Status Scale (EDSS). Seroprevalence of antibodies against SARS-CoV-2 was 83.3% in our sample. Development of antibodies was not associated with DMT, lymphocytopaenia, or any of the other variables analysed. Conclusions: The incidence of COVID-19 was slightly higher in our sample than in the general population in our province. Unfavourable prognosis was associated with older age and higher EDSS scores. DMT and lymphocytopaenia did not influence the clinical course of COVID-19. Seroprevalence of antibodies against the virus in our sample was similar to that reported for the general population with positive PCR results for the virus; the influence of specific DMTs could not be determined. Resumen: Introducción: El efecto de la infección por SARS-CoV-2 en los pacientes con esclerosis múltiple (EM) y la influencia de los tratamientos modificadores de la enfermedad (TME) es desconocida. Hasta el momento no se ha observado que los pacientes con EM tengan mayor riesgo de infección por COVID-19 ni peor curso evolutivo de la misma. Métodos: Estudio descriptivo de pacientes con EM e infección por SARS-CoV-2 diagnosticada mediante PCR. Hemos analizado variables demográficas, clínicas, de laboratorio y de tratamiento en nuestra muestra. Se ha determinado la presencia de anticuerpos frente SARS-CoV-2 en estos pacientes. Resultados: La forma de esclerosis múltiple remitente recurrente (EMRR) fue la más frecuente en los pacientes con EM e infección por COVID-19. El 10.2% presentó una evolución desfavorable, relacionada con una mayor edad y una EDSS más elevada. La seroprevalencia de anticuerpos frente a SARS-CoV-2 en nuestro estudio ha sido del 83,3%. El desarrollo de anticuerpos no está relacionado con el TME, la presencia de linfopenia u otros factores analizados. Conclusiones: La incidencia de COVID-19 ha sido ligeramente superior a la de la población general de nuestra provincia. La evolución desfavorable se ha relacionado con una mayor edad y una puntuación elevada en la EDSS. El TME y la linfopenia no se han relacionado con el curso de la infección por COVID-19. La seroprevalencia es similar a la encontrada en población general con PCR positiva, sin poder determinar la influencia de los distintos TME.

Background: The Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) is the cause of the Coronavirus Diseases of 2019 (COVID-19). This virus has been responsible for the global pandemic of 2020 and 2021 with over 107 million confirmed cases and over 2.3 million deaths. An important population that deserves meticulous consideration during the COVID-19 pandemic is pregnant woman; however, in many places in the world there is inadequate screening for SARS-COV-2 during pregnancy. We aimed to determine the impact of maternal and neonatal cord blood SARS-COV-2 antibodies and placental transfer ratios in a region with a low screening plan. Methods: We performed a blind study in Babahoyo, Ecuador; one of the SARS-CoV-2epicenters in South America. Blood samples were collected from 100 serum samples collected from pregnant women at the time of delivery along with corresponding neonatal cord blood. SARS-CoV-2 IgG specific antibodies were determined using a enzyme linked immunosorbent assay (ELISA) for IgG and IgM SARS-CoV-2-specific nucleocapsid and spike antigens (DiaPro, Milano, Italy Cat number COV19G.CE). Findings: We observed 32% of pregnant women to be serological positive in areas lacking an appropriate screening program. We also show data that suggests an efficient passive immunization of the fetus to SARS-CoV-2 during pregnancy. Interpretation: There is a high incidence of SARS-CoV-2 infection during pregnancy. The best prevention for protecting the mother from infection is vaccination, which, will provide the fetus and neonate with a strong protection against SARS-CoV-2 infection through passive placental transfer of SARS-CoV-2 specific antibodies. This is especially important because newborns are highly susceptible to many viral infections. Funding: NIAID 1R01AI145829-01 Declaration of Interest: None to declare. Ethical Approval: This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines. This was retrospective study done with samples sent for tests evaluation that were originally not related to this study. A consent waiver was approved since the samples were not collected for the study and the samples used were defined as dischargeable material.

Background: The prevalence of hepatitis B varies (HBV) among countries. Although an overall reduction has been described in Greece, data are limited. Methods: We reviewed the HBsAg/anti-HBc/anti-HBs seroprevalence among military recruits and compared data between 2005 and 2019. The study included 2001 (group 1) and 1629 (group 2) male recruits in 2019 and 2005, respectively. Age and descent were recorded. Results: The prevalence of HBsAg, anti-HBc and anti-HBs positivity in group1 vs. group 2 was estimated as: 0.2%, 1.3% and 67% vs. 0.4%, 1.6% and 62%, respectively. Only anti-HBs positivity achieved a statistically significant difference between the two groups (p = 0.007). HBsAg and anti-HBc were more frequently positive in non-Greeks than in Greeks (9/237 (4%) vs. 2/3393 (0.06%), p < 0.001), (26/237 (11%) vs. 26/3393 (0.8%), p < 0.001 respectively), while anti-HBs was more frequently positive in Greeks than in non-Greeks (84/164 (51%) vs. 1461/2213 (66%), p < 0.001). Conclusions: Our data suggest a further reduction in HBV prevalence in Greece about 20 years after the adoption of the National HBV Immunization Program, with Greek participants experiencing a more effective HBV Immunization Program than non-Greeks.

Background: Human toxocariasis is caused by Toxocara canis and T. cati, the nematodes in the intestine of dogs and cats, respectively. Since the association between asthma and toxocariasis is controversial, the aim of the present study was to investigate the seroprevalence of Toxocara infection among asthmatic children in comparison with healthy children. Methods: This case-control study was conducted on 92 asthmatic and 91 healthy children aged 1-16 years old in Shiraz City, Southern Iran in 2019-2020. The serum samples were tested for IgG anti-Toxocara antibodies by ELISA method using the T. canis larval excretory-secretory (E/S) antigens. The collected data were analyzed using SPSS software. Results: The seroprevalence of toxocariasis in asthmatic patients was higher than the healthy children with no significant difference in Toxocara seropositivity between two groups (9.8% vs 8.8%, P = 0.817). The association between Toxocara infection and variables such as gender and age were not statistically significant. Conclusion: There was no significant association between toxocariasis and childhood asthma. Further study on different regions such as urban and rural areas with a large sample size and using questionnaire for considering risk factors of asthma and toxocariasis is recommended.

Objective: Patients with chronic rheumatic diseases (CRDs), such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), require special attention during the COVID-19 pandemic as they are considered at risk of severe infections. Our objective was to assess the seroprevalence of SARS–CoV-2 in patients with SLE and RA and to assess patient behavior, disease-related symptoms, and mental health. Methods: More than 900 participants were included: 405 patients with RA or SLE (CRD patients) and 513 blood donors. All participants had blood SARS–CoV-2 total antibodies measured (sensitivity 96.7%, specificity 99.5%) and answered a questionnaire concerning behavior, anxiety, and symptoms of depression (Patient Health Questionnaire 9). The CRD patients were further asked about physical activity, adherence to medication, and disease-related symptoms. Results: CRD patients had a significantly lower seroprevalence of SARS–CoV-2 antibodies (n = 1 of 365, 0.3%) compared to blood donors (n = 10 of 513, 1.9%; P = 0.03). Almost 60% of patients were unable to exercise as usual, and increased pain and disease activity was experienced by 34% and 24% of patients, respectively. Almost 10% of patients reduced or discontinued their immunosuppressive treatments at their own initiative. Symptoms of moderate depression were present in 19% of patients compared to 6.8% of blood donors (P < 0.001). Conclusion: Low seroprevalence in patients with CRDs indicates successful mitigation of exposure to SARS–CoV-2. However, this mitigation appears to occur at the expense of physical activity, experience of increased pain, disease activity, and symptoms of depression. There is a need for care providers to be aware of these negative side effects and for further studies to investigate the possible long-term consequences.

This study was designed to investigate the seroprevalence and impact of Haematological and biochemical markers of dengue virus infection among subjects co-infected with hepatitis B virus infection in Enugu State, Nigeria. The study involved a cross-sectional study consisting of 150 subjects (120 discordant and concordant partners of hepatitis B, and 30 controls). Dengue Virus IgM and IgG were analyzed using ELISA rapid kit while HBsAg was screened using a rapid ELISA diagnostic strip. Both Dengue and HBsAg were re-screened later to reaffirm the result using Ichroma Fluorescence Immunoassay (FIA). Haematological parameters were analyzed using Mindray autoanalyser while ALT/AST was analyzed using COBASS 111. Statistical analysis was performed using Graph Pad Prism. The results showed a prevalence of 44.7% dengue virus seropositivity among the study population, 43.3% in dengue/hepatitis B co-infected subjects. The dengue virus seropositive participants had significantly greater IgG (70.1%) levels compared to IgM (29.9%), more in females (68.6%) compared to males (31.4%), and predominantly in the age group 31 to 40 years. A significant higher (p

Zika virus (ZIKV) is one of the arboviruses implicated in febrile illness, microcephaly and other neurological disorders in babies whose mothers were infected during pregnancy. Information on ZIKV in Nigeria is limited. Hence, this study was aimed at investigating the seroprevalence of Zika virus among pregnant women in Lagos State. In a cross-sectional study, blood samples collected from 352 randomly selected pregnant women in four hospitals in Lagos State were separated and plasma analyzed using Zika virus IgG and IgM capture Enzyme-linked immunosorbent assay (Demeditec Diagnostics, Germany). The optical densities were read using Precision Microplate reader (Molecular devices) and cut-off calculated according to manufacturer’s guide. Parameters and symptoms such as history of fever, rashes on the body, exposure to mosquito were extracted from the questionnaire and analyzed. IgM seropositive samples were screened for ZIKV RNA on RT-qPCR. Out of 352 samples screened, 7(2.0%) and 5(1.4%) of the pregnant women tested positive for IgG and IgM respectively. None tested positive for both IgG and IgM markers. Statistical analysis showed that there is no significant relationship between the symptoms analyzed in this study at 95% Confidence interval except conjunctivitis. None of the ZIKV IgM seropositive samples tested positive for ZIKV RNA on RT-qPCR. The results show that there is evidence of exposure to Zika virus among the population studied in Lagos, Nigeria. Also, the low level seroprevalence of the virus in the population studied indicates that there is lack of herd immunity of Zika virus infection in Lagos, Nigeria.

The present study aimed to evaluate the possible association between coronavirus disease 2019 (COVID-19) and latent Toxoplasma gondii infection in a group of patients and healthy individuals. Blood samples were obtained from 269 PCR-positive COVID-19 patients. The serum was separated and tested for the existence of anti-T. gondii antibodies (IgG) using a commercial enzyme-linked immunosorbent assay kit. The prevalence of latent toxoplasmosis between a subgroup of the patients (aged under 55 years old) and COVID-19 negative individuals was compared. Anti-T. gondii antibodies were found in 226/269 (84.0%) patients with COVID-19. Anti-Toxoplasma antibodies were detected in 72/91 (79.1%) cases and 96/123 (78.0%) COVID-19 negative individuals (odd ratio = 1.1; 95% confidence interval: 0.55–2.07, P = 0.85). The median and interquartile range (IQR) of the IgG titer were not statistically significant different between case (97.3 [31.0–133.5]) and control groups (34.4 [13.0–144.5]) (P = 0.10). These findings demonstrated that latent Toxoplasma infection is prevalent amongst the COVID-19 patients. It also did not find any significant association between chronic toxoplasmosis and COVID-19.

Aims: Livestock is the largest subsector of the Sudanese domestic economy and is a growing contributor to exports. Rift Valley fever (RVF) is an economically important arthropod-borne virus disease in Africa, primarily affecting sheep, goats, and cattle. RVF causes paramount loss in sheep industry in Sudan. The objective of this study was to detect RVF in sheep. Methodology: Five hundred and fifty-six sheep blood Serum from inoculated animals was collected from six study areas in the Gezira (Sudan)was evaluated for the presence of neutralizing antibodies using the diagnostic kit (ID. Vet.) for detecting antibodies directly against the RVFV nucleoprotein (NP) in serum and Reverse transcription (RT)-Polymerase Chain Reaction (PCR) protocol was used as standard test to diagnose and confirm RVFV among studied animals. Results: The ELISA test indicated that the highest Seroprevalence was found at Shikaira (38%), while samples from Albasabeir, Wad alnaem and Umalqura tested positive for antibodies against RVFV by 15%, 10% and 9% respectively. The lowest Seroprevalence found at Wad anor and Shabona (5% and 2%). The overall seroprevalence was 14.2% in the study sites, there is no significant difference among the six study sites with respect to seroprevalence. The Rt-PCR provided more sensitive and specific detection of RVFV in serum samples (sensitivity= 95% specificity = 80%). Conclusion: The results from this study showed the presence of anti-RVFV antibodies in all study sites, suggesting that RVFV is actively circulating among sheep in Gezira state. The high seroprevalence of RVFV infection in Gezira state indicates its endemicity. Test validation using ROC analysis was able to distinguished between ELISA (actual class) and the PCR (predicted class) and the AUC = 0.79 which indicate that the PCR is gold standard test. Thus Rt-PCR used in the present study is reliable to detect precisely the M segment of RVFV and it is valuable for Wide area survey, among both sheep and Aedes spp. Targeting the prevailing genotypes of RVF-M segment, especially at high-risk areas and as a confirmatory test that should be considered by reference laboratories in the region.

Kachia and Kagarko LGAs are among the LGAs that have been treated with Ivermectin consistently for 19 years according to the records of Kaduna State Ministry of Health. Hence this study was carried out to conduct an appraisal of these selected areas in order to determine its efficacy, longevity and corroborate or otherwise the issue of recrudescence of the disease. A cross sectional study was conducted in May, 2018 to investigate the prevalence of onchocerciasis in Kachia and Kagarko LGAs of Kaduna State, Nigeria. A total number of 208 participants were screened using SD Bioline onchocerciasis IgG4 kit from the two LGAs, 23 (11.1%) were found to be positive for IgG4 antibodies to O. volvulus. Result of the Chi square analyzes showed that there were no significant association between sex and seroprevalence (X2=0.377, df=1, p=0.593), LGAs and seroprevalence (X2=1.119, df=1, p=0.290, CI=95%) however, a significant association between age and seroprevalence (X2=13.408, df=5, p=0.020) was recorded. Occupationally, the LGAs had a significant association (X2=14.420, df=4, p=0.006). In Kachia LGA, there was equally a significant association (X2=10.848, df=4, p=0.028) while, in Kagarko there was no significant association (X2=5.866, df =4, p=0.209) in the seroprevalence. Significant association was equally recorded between seroprevalence and compliance to ivermectin in Kachia (X2=27.419, df=1, p=0.05) and Kagarko (X2=33.269, df=1, p=0.05). Conclusively, there was reduction in Onchocerca infection due to adherence to ivermectin intake by the inhabitants. Therefore, regular surveillance of endemic areas is to be carried out promptly in order to ensure compliance to prescribed annual ivermectin dosage and identify and treat infected individuals

Resumen Introducción. Las rickettsiosis son enfermedades zoonóticas transmitidas por artrópodos que cumplen el papel de vectores y reservorios, y cuyos síntomas son inespecíficos, por lo que su diagnóstico clínico es difícil. La inmunofluorescencia indirecta (IFI) es el método de referencia para el diagnóstico. En Colombia, ha resurgido el interés por su estudio por los casos de rickettsiosis detectados en el norte del departamento de Caldas a partir del 2001. Objetivo. Establecer la frecuencia de anticuerpos y la seroconversión contra Rickettsia spp. en pacientes atendidos en instituciones de salud del departamento de Caldas, Colombia, entre 2016 y 2019. Materiales y métodos. Se hizo un estudio de diseño cuantitativo, observacional y descriptivo, con una muestra no probabilística de 175 pacientes atendidos en diferentes municipios de Caldas, a quienes se les realizó IFI para la detección de anticuerpos en fase aguda y convaleciente contra Rickettsia rickettsii, R. typhi y R. felis. Resultados. El promedio de edad de los pacientes fue de 31 años. Los municipios con mayor proporción de seropositivos fueron Belalcázar, Chinchiná, Filadelfia, La Dorada, La Merced y Manizales. El 66 % tenía mascotas y el 12 % reportó picaduras por artrópodos. Los signos y síntomas más frecuentes fueron cefalea (69,7 %), artromialgia (60 %), y fiebre (58,2 %). La seroprevalencia por IgG fue de 60 % para R. rickettsii, 47,9 % para R. typhi y 24 % para R. felis. Ocho pacientes presentaron seroconversión. Conclusión. Se encontró evidencia de la circulación de rickettsias del grupo de las fiebres manchadas y del grupo del tifus asociada con casos humanos en el departamento de Caldas. Abstract Introduction: Rickettsioses are zoonotic diseases transmitted by arthropods acting as vectors and reservoirs. Disease symptoms are nonspecific and, therefore, their clinical diagnosis is difficult. Indirect immunofluorescence (IFA) is the gold standard assay for diagnosis. The interest for conducting studies on these pathologies has resurfaced in Colombia since 2001; besides, previous studies have evidenced cases of rickettsiosis in the north of the department of Caldas. Objective: To establish the frequency of antibodies and seroconversion against Rickettsia spp. In patients consulting health institutions in Caldas, Colombia, from 2016 to 2019. Materials and methods: We conducted a quantitative, observational, and descriptive study on a non-probabilistic sample of 175 patients with symptoms compatible with rickettsiosis who consulted in different municipalities of Caldas, Colombia; IFA was performed to detect antibodies in the acute and convalescent phases against Rickettsia rickettsii, Rickettsia typhi, and Rickettsia felis. Results: The average age of the patients was 31 years. The municipalities with the highest proportion of seropositive cases were Belalcázar, Chinchiná, Filadelfia, La Dorada, La Merced, and Manizales; 66% of patients owned pets and 12% reported arthropod bites. The most frequent signs and symptoms were headache (69.7%), arthromyalgia (60%), and fever (58.2%). IgG seroprevalence was 60% for R. rickettsii, 47.9% for R. typhi, and, and 24% for R. felis. Eight patients presented seroconversion. Conclusion: We found evidence of the circulation of Rickettsia species from the spotted fever group and the typhus group associated with human cases in Caldas.

Background and Objective: In recent years, respiratory tract viral infections have caused many pandemics that impact the whole world. To investigate the seropositivity of Toxoplasma gondii, rubella, CMV, HSV-1 and group A Streptococcus in recovered COVID-19 patients and correlate these findings with vitamin D levels. Materials and Methods: A total of 417 COVID-19 patients with diarrhoea were enrolled in this study. Vitamin D and seroprevalence for Toxoplasma gondii, rubella, CMV, HSV-1 and group A Streptococcus were evaluated and correlated. Results: It was found that recent infection in COVID-19 patients with HSV-1, rubella, Toxoplasma and CMV, respectively. IgG was detected indicating the development of adaptive immunity with all microbes. Conclusion: Current study detected a correlation between vitamin D levels and HSV-1 and no correlation between this infection and vitamin D deficiency with the other microbes.

Viral hepatitis is a serious health problem globally and in endemic countries like Bangladesh. Viral hepatitis may present as mono-infection or co-infection caused by Hepatitis A Virus (HAV), hepatitis B virus, hepatitis C virus, hepatitis D virus, and Hepatitis E Virus (HEV).

Purpose To assess the IgG seroprevalence of Toxoplasma gondii as an indicator of past exposure and immunity against infection among children with Down syndrome (DS) in Sana’a city, Yemen. This preliminary study is justified by the primary immunodeficiency of children with DS and the opportunistic nature of the parasite, considering the vague situation of anti-Toxoplasma IgG seroprevalence among children with DS because of neglecting its study on local and global scales. Methods This descriptive, facility-based, cross-sectional study was conducted among 107 children with DS hosted in six randomly selected rehabilitation centers for children with special needs in Sana’a city. Demographics of children and their mothers’ knowledge of toxoplasmosis were collected using a pre-designed, structured questionnaire. Anti-Toxoplasma IgG antibodies were measured in the sera of children using electrochemiluminescence assay. Results Of 107 children with DS, 3 (2.8%) were seropositive for anti-Toxoplasma IgG. Approximately two-thirds (71/106) of the mothers of children with DS were aware of toxoplasmosis. Of whom, 83.1% (59/71) were aware of its congenital complications. Conclusion The majority of children with DS in Sana’a city are seronegative for anti-Toxoplasma IgG, where the seropositivity rate is lower than 3.0%. Therefore, children with DS are non-immune and susceptible to the acquisition of primary infections during their life. Further analytical studies are recommended to determine whether the defective immune response of children with DS is associated with false seronegativity, to assess the role of their mothers’ knowledge in reducing their exposure to infection if they were confirmed truly seronegative and to identify the predictors of infection among them.

The epidemiology of HDV infection worldwide is obscure. Mapping the epidemiology of the infection is highly required, so, we aimed to estimate the prevalence of hepatitis D virus infection among chronic hepatitis B patients and the epidemiological characteristics in the Nile delta in Egypt. This was a prospective observational cross-sectional study including consecutive chronic hepatitis B patients in the out-patient clinics at the Egyptian Liver Research Institute and Hospital (ELRIAH) and its satellites in the Nile Delta from January 2016 until August 2018. They were recruited from patients enrolled in Educate, Test and Treat program, which was implemented in 73 Egyptian Villages. Subjects were tested by using HBsAg serological rapid diagnostic tests (RDTs), and then HBV DNA by PCR was done in HBsAg-positive cases. HDV IgG antibody testing and confirmatory HDV RNA PCR were done. Complete liver functions, abdominal ultrasonography and FibroScan were also performed. The prevalence of HDV was 3.4% using anti-delta antibody (22/631), and only 8 were positive for HDV RNA (8/22, 36.4%). Overall HDV prevalence using PCR was 8/631(1.27%). HDV-positive cases were mainly males (68.2%). Eight cases were cirrhotic (36.4%), 3 (13.6%) had HCC and 7 (31.8%) were HBeAg positive. HDV prevalence is low among chronic hepatitis B patients in the Nile delta, Egypt. Screening for HDV IgG is recommended in CHB patients who had cirrhosis, HCC or HBeAg positive.

Background. Mycoplasma pneumoniae (M. pneumoniae) is implicated in several immune-mediated extrapulmonary manifestations, including reactive arthritis. Recently, increased total serum IgE were reported in children developing M. pneumoniae-related extrapulmonary diseases (MpEPDs). Here, we aimed at analyzing these aspects in children affected with rheumatic disorders and, in detail, Juvenile Idiopathic Arthritis (JIA). Methods. M. pneumoniae serology (IgG and IgM) and total serum IgE were concomitantly analyzed in 139 pediatric patients diagnosed with: JIA (Group 1, n = 85 ), or any rheumatic disease other than JIA (Group 2, n = 27 ), or non-inflammatory endocrinological disorders (Group 3, n = 27 ). Results. Overall, 19.4% M. pneumoniae seroprevalence was observed in this hospitalized pediatric population, without signicant differences among the three groups. No significant differences in total serum IgE levels were noted among these groups; however, a second analysis excluding children with very high (and clearly abnormal) IgE levels suggested that JIA patients and, in detail, those with oligopolyarticular forms may have higher serum IgE concentrations. This relative difference among groups in serum IgE level seems to be more pronounced in M. pneumoniae seropositive children. Conclusions. M. pneumoniae infection should be actively sought in children developing immune-mediated diseases, including patients affected with JIA and, especially, in oligopolyarticular forms. There is some evidence that total serum IgE levels may tend to be increased in patients with oligopolyarticular JIA subtype and especially in those resulting as M. pneumoniae seropositive. However, further and focused research is needed to confirm these preliminary results and to clarify the relation between M. pneumoniae infection, atopic status, and immune-mediated arthritis.

A cross-sectional study was carried out to determine the seroprevalence and risk factors of Q fever in sheep in the northern part of Kaduna State, Nigeria. This study aimed to determine Coxiella burnetii infection and its risk factors in sheep in Kaduna State. A total of 400 blood samples consisting of 259 samples from females and 141 from males were aseptically collected from the jugular vein of sheep from flocks in Kaduna State. The sera obtained were screened for Q fever using an indirect enzyme-linked immunosorbent assay (iELISA). The obtained data were analysed to determine whether there is a relationship between sex, age, and the animals tested. The analysis revealed that 8.0% of the sera was seropositive by iELISA. There was no significant difference in Q fever seropositivity in the study area according to the sex of sheep (P > 0.05). There was a statistically significant difference (P < 0.05) in Q fever seropositivity according to the age of sheep. This study indicated a high seroprevalence of Q fever mainly among female animals and older sheep. Further studies are required to determine the epizootiology of Q fever in the study area more precisely.

Background: Human herpesvirus type 8 (HHV-8) can be transmitted through unprotected sex as HIV. We aimed to investigate the seroincidence of HHV-8 and associated factors among people living with HIV (PLWH). Methods: From 2014 to 2018, blood samples of PLWH on the first date of HIV care were determined for antibodies against HHV-8. Individuals testing HHV-8-seronegative at baseline were followed for at least four months to estimate the annual seroconversion rate. To identify the factors associated with HHV-8 seroconversion, we compared the clinical characteristics between seroconverters and non-seroconverters who were matched for observation duration. Results: The HHV-8 seroprevalence increased from 8.1% in 2014 to 20.0% in 2018. HHV-8 seroconversion occurred in 154 (14.7%) PLWH after a total of 2652.16 person-years of follow-up (PYFU), resulting in an overall incidence rate of 5.62 per 100 PYFU, which increased from 3.20 to 6.84 per 100 PYFU during the study period. HHV-8 seroconverters were less likely to have chronic hepatitis B virus (HBV) infection (1.9% vs 10.6%) and more likely to be antiretroviral-naïve on entry into care (87.7% vs 75.4%) (both p

Q fever is an important zoonotic disease worldwide. The main sources of human infection are inhalation of aerosols containing Coxiella burnetii bacteria and exposition to infected materials during parturition or slaughtering. The high-risk group includes people who work directly with infected livestock, such as farmers, veterinarians, veterinary medicine students, slaughterhouse and laboratory staff. Here we present a pilot study of risk-group human seroprevalence to C. burnetii in Latvia. The study included 240 sera samples — 190 from the risk groups and 50 from the control group. Samples were tested with Coxiella burnetii (Q-fever) Phase 1 and 2 IgG ELISA kits. All sera from the control group were negative. The seroprevalence among risk group persons was 8.04–11.54%. No statistically significant differences were observed between genders. The highest percentage of seropositive and equivocal sera samples (25%) were detected in age categories 39–48 years and 49–58 years. Working as a practicing veterinarian or former veterinarian was the only risk factor identified as statistically significant, and belonging to the risk group in general. The geographical distribution of seropositive risk group participants indicated that they tend to located more in the northern, central, and eastern part of the country.

Objectives: To describe the current panorama of severe chickenpox disease and seroprevalence in Sweden, as a basis for the approaching decision on universal vaccination. Methods: Patients discharged with an International Classification of Diseases 10th revision-code for chickenpox (B01-B01.9) in eight pediatric and infectious diseases departments in Stockholm and Gothenburg in 2012-2014 were included in the study and their medical charts were reviewed. Further, residual serum samples collected from 11 laboratories across Sweden were analyzed for varicella zoster IgG-antibodies to investigate age-specific seroprevalence. Results: A total of 218 children and 46 adults were included in this hospital-based study; 87.2% of children and 63.0% of adults had complications. An underlying condition was not associated with an increased risk of complication. Dehydration (31.7%), bacterial skin infections (29.8%) and neurological involvement (20.6%) were the most frequent complications in children. Among adult cases, 63% were born abroad. The seroepidemiological analysis included 957 patient samples. Seroprevalence was 66.7% at 5 years and 91.5% at 12 years. Infants and adolescents/adults were overrepresented among admitted patients compared to seroprevalence data. Conclusions: Half of all complications in hospitalized chickenpox cases were seen in previously healthy children, which supports universal childhood vaccination. Adult migrants was a risk group for chickenpox hospitalization. Age-specific seroprevalence was similar to neighboring countries.

Crimean-Congo hemorrhagic fever (CCHF) is described as a tick-borne viral zoonosis highly prevalent in Africa, Asia, Russia and the Balkans within the distribution range of ticks that belong to the genus Hyalomma. This research aimed to verify the seroprevalence of CCHF in cows employing Indirect enzyme-linked immunosorbent assay (I-ELISA) in Mosul city / Iraq, to ​​examine some epidemiological risk factors related to the incidence of CCHF. From October 2019 - September 2020, one hundred eighty-four blood samples were taken from 3-8-year-old cattle of both sexes, from several management systems and origins, from various parts in Mosul city, 10 ml of blood was taken from the jugular vein in test tubes without anticoagulant to obtain the sera for I-ELISA test, while epidemiological data were obtained by interviewing the farm-owners. I-ELISA was applied to detect the antibodies of CCHF in the serum. The overall seroprevalence of CCHF in cows was 40/184 (21.7%). As for the risk factors associated with increased seroprevalence of the disease, an increase in seroprevalence rates was observed at ages 6, 7 and 8 years 30.5%, among females 26.3% and imported animals 27.5%. which showed that the serological prevalence in indoor feeding and outdoor feeding, was not significantly different (p

Background Regular outbreaks of chickenpox are reported among cadets and recruits in the army undergoing training, resulting in morbidity and loss in terms of training days. Vaccination policy in the army mandates that all cadets and recruits be vaccinated against chickenpox on joining the training centers. However, 100% vaccination of trainees is not achieved. Hence, seroprevalence data among cadets and recruits were collected with the aim to assess the need for vaccination against chickenpox. Methods The data were collected from cadets and recruits undergoing training in military training centers by simple random sampling. Blood samples were collected from all study participants for IgG enzyme-linked immunosorbent assay for varicella zoster. A structured questionnaire was also used to collect information from all participants. Results A total of 2041 cadets and recruits between the ages of 19–29 years were studied of which 96.1% were males. Of all participants, 49.9% were seropositive showing varicella zoster virus (VZV) IgG antibody in the serum, and 29.1% study participants gave positive history of having had varicella in the past. The sensitivity of definite positive history of varicella when compared with presence of VZV IgG antibodies was found to be 55.50% while specificity was found to be 97.17%. Conclusion A very large majority of cadets and recruits that joined the army are susceptible to chickenpox. Hence, the risk of repeated chickenpox outbreaks in these training centers remains very high. As the sensitivity of history of past infection of chickenpox is relatively low, it cannot be used as a tool to determine the susceptibility of the trainees to the infection.

Supplemental Digital Content is available in the text., Background. Data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in kidney transplant recipients (KTRs) remain rare. We sought to shed further light on this issue by conducting a single-center study in a kidney transplant center located in one of the France’s highest risk zone (Grand Est) for coronavirus disease 2019 (Covid-19) during the initial disease outbreak. Methods. To this aim, we used a survey approach coupled with systematic investigation of SARS-CoV-2 serology in a cohort of 1390 KTRs. Results. SARS-CoV-2 serologies were available for 780 survey respondents, among whom 48 had anti-SARS-CoV-2 antibodies (total seroprevalence: 6.2%). Thirty-five of the 48 seropositive KTRs had previously received a diagnosis of Covid-19, whereas the remaining 13 patients were not known to be infected (8 asymptomatic cases). Specifically, 18.7% of seropositive KTRs and 1.1% of the entire cohort were asymptomatic. Household exposure was found to markedly increase the risk of SARS-CoV-2 transmission. Conclusions. Our findings demonstrate that the overall SARS-CoV-2 seroprevalence in KTRs living in one of the France’s highest risk zone for Covid-19 during the first French lockdown was as low as 6.3%. Rapid and strict implementation of protective measures could have significantly mitigated virus spread even in an area of high virus circulation.

Background A large proportion of SARS‐CoV‐2‐infected individuals does not develop severe symptoms. Serological tests help in evaluating the spread of infection and disease immunization. The aim of this study was to prospectively examine the trends and risk factors of SARS‐CoV‐2 infection in blood donors. Study design and methods We screened 8798 asymptomatic donors presenting in Milan from July 2020 to February 2021 (10,680 presentations) before the vaccination campaign for anti‐nucleoprotein (NP) antibodies, and for anti‐spike receptor‐binding domain (RBD) antibodies and nasopharyngeal swab PCR in those who tested positive. Results The prevalence of anti‐NP+/RBD+ tests increased progressively with time up to ~15% (p 80 AU/ml). Anti‐RBD titers declined during follow‐up, depending on baseline titers (p

One of the biggest infectious diseases for humans in modern history is the COVID-19 pandemic. The disease mechanisms of human viral infections have been modified by virus-virus interaction. This study was carried out to detect the seroprevalence of CMV in COVID-19 patients. A total of 105 cases (58 females and 47 males) with an age range of 17-65 years (mean age 39.52±11.02 years) were included in this study. HCMV-IgG and IgM were determined in subjects' cases. Sixty-five out of 105 (62%) were positive for SARS-CoV-2, while 40 (38%) had negative SARS-CoV-2. Forty-seven (72.3%) and 11 (16.9%) cases out of 65 SARS-CoV-2 positive patients were positive for CMV-IgG and IgM antibodies, respectively. No significant differences were noted between females and males in terms of seroprevalence rates. A high rate of positive CMV-IgG was observed among 40-64 years COVID-19 patients. It is concluded that the seroprevalence of CMV antibodies amongst COVID-19 cases is high in relation to findings in cases without SARSCoV-2.

Introduction: District Sheikhupura encountered its first dengue outbreak in 2014 but lacked serological evidence and reports of risk factors associated with it. To assess this, a hospital-based study was conducted from January 2014 to December 2017. Methodology: Blood from 333 participants was collected, the serum obtained was tested for IgG and IgM antibodies against DENV using a commercially available ELISA kit. Results: The results showed that out of all (n= 333) samples tested, 120 were turned up positive for DENV, making an overall prevalence of 36%. Of the 120 confirmed cases, 55% (n = 66) were recorded in 2014, 10% (n = 12) in 2015, 27.5% (n = 33) in 2016, and 7.5% (n = 9) in 2017. It was found that 68.3% (n = 82) were male and 31.7% (n = 38) were female, with 61% (n = 74) patients aged between 11-30 years. The highest prevalence of infection, 94.2% (n = 113), was noted after the rainy season. During the study, the highest number of cases appeared in Ferozewala Tehsil. The factors age, gender, and season were found statistically significant with the prevalence of infection (p < 0.05). Conclusions: The study is the first report on the detection of dengue in the Sheikhupura district. The survey anticipated its geographical expansion, determined associated risk factors, and suggests active disease surveillance in the area.

Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii which can have serious consequences for the fetus in case of pergravidicseroconversion. The present work is analytical and descriptive complementary studies: prospective (1-09-2015 to 31-12-2015) and a retrospective study (01-01-2010 to 31-12-2014) performed in the service of Parasitology - Mycology Marrakesh.The seroprevalence of pregnant women immunized against toxoplasmosis in our study is 35%, including women from rural and illiterate are proven to be the most immune. The main risk factors for disease transmission are the lack of knowledge about toxoplasmosis, the modes of transmission and means of prevention, and the low level of hygiene. We also raised a blatant lack of regular serological monitoring in seronegative pregnant women who received only one serological test in 66%. The present study confirmed that more than half of pregnant women are not immunized against Toxoplasma gondii and deserve monthly monitoring for early detection of possible seroconversion and implement effective therapeutic management.

The Epstein-Barr virus (EBV) infection status in patients with inflammatory bowel disease (IBD), particularly those using thiopurines, may be associated with the risk of lymphoproliferative disorder and hemophagocytic lymphohistiocytosis. This was the first multicenter survey of EBV infection in Japanese patients with IBD. Factors related to the EBV infection status were also investigated.Five tertiary institutions in Japan participated in this study to examine pediatric and adult patients with IBD. Serum EBV anti-viral capsid antigen (VCA) IgG, EBV anti-VCA IgM, and anti-EBV nuclear antigen-antibody were measured in 495 patients with IBD. The patients' information was obtained from their medical records. Prior EBV infection was defined as anti-VCA IgM negativity and anti-VCA IgG positivity (UMIN000033004).The patients' median age was 25 years (range 0-92 years). Of the 495 patients, nine were anti-VCA IgM-positive and 354 were anti-VCA IgG-positive (seroprevalence: 72.8%). The proportion of patients with prior EBV infection was 0% for those aged 5 years, 60% for those aged 30 years, and 90% for those aged 30 years. The proportion of EBV-uninfected patients using thiopurines was 28.4% (52/183) for all patients and 51.8% (44/85) for pediatric patients. Age was significantly associated with anti-VCA IgG seropositivity (p 0.01, odds ratio: 0.902, 95% confidence interval: 0.880-0.925). No cases of lymphoproliferative disorder, hemophagocytic lymphohistiocytosis, or chronic active EBV infection were reported.Approximately 30% of Japanese patients with IBD were EBV-uninfected, including those using thiopurines. Age was a significant factor for anti-VCA IgG seropositivity.