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Hepatopancreatic microsporidiosis caused by Enterocytozoon hepatopenaei (EHP) is an emerging parasitic disease causing great economic losses in almost all shrimp-growing countries. The disease is reported to be associated with severe growth retardation, size variation, and ultimately farm productivity. This study investigated the impact of various infection routes (viz. per os, cohabitation, water-borne and soil-borne) of EHP on disease progression. Per os (oral feeding) challenged shrimp acquired infection at a faster pace and could be detected in 100% of experimental shrimps by 5 days post-infection (dpi) as compared to 15 dpi by cohabitation method. The first detection of faeces of shrimp by water-borne infection was at 7 dpi compared to 15 dpi in the case of soil-borne infection. Soil- and water-borne infections were detectable in 100% of shrimps by 15 and 30 dpi, respectively. Nested PCR revealed a prepatent period of 5 days in case of oral and cohabitation challenge and 7 and 15 days in case of acquiring infection through water and soil sediments, respectively. Thus, a faster and higher level of infection was observed by oral challenge than other methods of infection. It could be inferred that the clinical course and pathogenicity of E. hepatopenaei infection at different time points is determined by the type of exposure, relative size group of the shrimp, and the quantum of infective spores (inoculum) ingested by the shrimp. [ABSTRACT FROM AUTHOR]

Biopesticides have received increasing global attention as environmentally friendly alternatives, allowing for more sustainable pest and disease control. In order to be registered or authorized for use, safety studies need to be submitted for regulatory risk assessments. However, it has been frequently reported that, in particular, microbial pesticides have a number of challenges when it comes to non-target organism testing. For instance, study results from such tests are often difficult to interpret or they lack consistency and accuracy. Reasons for this can be found firstly in the heterogeneity and resulting complexity of microbe-based pesticides comprising different taxonomic groups (e.g., bacteria, fungi, and viruses), and secondly in the lack of appropriate guidance for testing these different microbial agents considering their unique biological properties. The present review gives an overview of the available test guidelines by reflecting the current regulatory background in the area of environmental risk assessment of microbial pesticides and describes general and specific issues associated with safety studies on terrestrial vertebrates, aquatic organisms, bees, non-target arthropods other than bees, meso- and macro-organisms in soil, and non-target terrestrial plants. Proposals for improvement of existing test guidelines or guidance documents are provided and further discussed. [ABSTRACT FROM AUTHOR]

Modeling studies of household transmission data have helped characterize the role of children in influenza and coronavirus disease 2019 (COVID-19) epidemics. However, estimates from these studies may be biased since they do not account for the heterogeneous nature of household contacts. Here, we quantified the impact of contact heterogeneity between household members on the estimation of child relative susceptibility and infectivity. We simulated epidemics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-like and influenza virus-like infections in a synthetic population of 1000 households, assuming heterogeneous contact levels. Relative contact frequencies were derived from a household contact study according to which contacts are more frequent in the father–mother pair, followed by the child–mother, child–child, and finally child–father pairs. Child susceptibility and infectivity were then estimated while accounting for heterogeneous contacts or not. When ignoring contact heterogeneity, child relative susceptibility was underestimated by approximately 20% in the two disease scenarios. Child relative infectivity was underestimated by 20% when children and adults had different infectivity levels. These results are sensitive to our assumptions of European-style household contact patterns; but they highlight that household studies collecting both disease and contact data are needed to assess the role of complex household contact behavior on disease transmission and improve estimation of key biological parameters. [ABSTRACT FROM AUTHOR]

Enterovirus-A71 (EV-A71) is the second most common causative agent after coxsackievirus A16 of hand, foot, and mouth disease. The capsids of EV-A71 consist of 60 copies of each of the four viral structural proteins (VP1-VP4). VP1 is highly exposed and surface accessible, playing a central role in virus particle assembly, attachment, and entry. To gain insight into the role of highly conserved residues at positions 75, 78, and 88 in the capsid protein VP1 in these processes, an alanine-scanning analysis was performed using an infectious cDNA clone of EV-A71. Our study revealed that the substitutions of VP1-T75A, VP1-T78A, and VP1-G88A could affect the assembly of the virus capsid proteins, resulting in the production of abnormal virions with reduced infectivity. Specifically, the substitution of VP1-T75A affected the maturation cleavage of the VP0 precursor, leading to deficiencies in binding to receptor scavenger receptor class B2 (SCARB2), viral attachment, internalization, and even uncoating. For the mutants of T78A and G88A, a significant reduction in virion-associated genomic RNA was observed, suggesting that more noninfectious empty particles were produced during viral assembly. Interestingly, the VP1-T75A variant showed weak replication in cell cultures but demonstrated increased virulence in BALB/c neonatal mice, which might be due to the difference in viral receptors among mammalian species. Taken together, our data revealed the important role of the highly conserved residues T75, T78, and G88 in VP1 protein in the infectivity of EV-A71. Characterizing these novel determinants of EV-A71 virulence would contribute to rationally developing effective treatments and broadly protective vaccine candidates. [ABSTRACT FROM AUTHOR]

We examined the infective capacity of the mermithid nematodes, Romanomermis iyengari, Romanomermis culicivorax, Romanomermis wuchangensis, and Strelkovimermis spiculatus in fourth-instar mosquito larvae nearing pupation of Aedes aegypti, Aedes sierrensis, and Culex pipiens to determine their prevalence in the adults of these mosquitoes. We exposed 100 fourth-instar larvae to pre-parasitic nematodes (juvenile 2 stages) at a ratio of 10:1 (10 nematodes per mosquito larvae). Two days after the nematode applications, a sample of 20 pupae was taken and placed into transparent plastic cups with distilled water to observe the development and growth of pupae until they reached the adult phase with nematodes inside. The four species of nematodes showed the highest prevalence of infection on the Cx. pipiens mosquito, exceeding 55% parasitism, while R. wuchangensis and R. iyengari surpassed this value on Ae. sierrensis by 61.11% and 57.89%. Aedes aegypti was the least susceptible to nematodes, with parasitism values between 30% and 40%. In laboratory settings, we obtained high rates (26.32–77.78%) of parasitized adults when the three-mosquito species in fourth-instar larvae nearing pupation were exposed to infective nematodes. R. wuchangensis (1.86) and S. spiculatus (1.80) were infected Cx. pipiens with greater intensity and R. iyengari (1.33) and R. culicivorax (1.09) with less intensity. This evaluation offers valuable insights into the variability of nematode prevalence of infection and infectivity in fourth-instar larvae, which host mermithids capable of progressing through the pupal stage to adulthood. [ABSTRACT FROM AUTHOR]

INTRODUCTION. Currently, rotavirus infection is prevented with live attenuated vaccines. However, international and Russian vaccination practices, as well as the physiological characteristics of paediatric patients, necessitate the development of inactivated rotavirus vaccines. Prerequisites for the development of such vaccines are the availability of virus strains capable of stable replication and the selection of optimal inactivation conditions providing for the required antigenicity and immunogenicity levels.AIM. This study aimed to evaluate and compare the characteristics of the rotavirus-specific immune response to native strains and to a composition of inactivated rotavirus A strains in a mouse model.MATERIALS AND METHODS. The study used human rotavirus A strains (RRV-4, RRV-5, RRV-6, and RRV-7), a standard rotavirus strain (SA-11 NVC 2364, National Virus Collection of the Russian Federation), and cultures of pig embryo kidney cells treated with Versene solution (SPEV) and Vero cells. Virus titration was used to determine the infectivity of the strains grown in Vero cells maintained in continuous culture. The authors monitored infected cell cultures up to the onset of the cytopathic effect, calculated the 50% tissue culture infectious dose (TCID50) by the Kärber method modified by Ashmarin, and expressed the results as log10 TCID50/mL. Virus strains were inactivated with formaldehyde. To evaluate immuno­genicity, outbred white mice were immunised with native strains and the composition of inactivated strains (RRV-4, RRV-5, RRV-6, and RRV-7). After immunisation, blood was taken from the animals, and the serum titre of rotavirus A antibodies was determined by indirect heterogeneous enzyme immunoassay.RESULTS. The infectivity of the rotavirus strains adapted to Vero cells ranged from 8.9 to 7.9 log10 TCID50/mL. When selecting inactivation conditions, the authors showed that inactiva­tion occurred at a temperature of 37 °C and a formaldehyde concentration of 0.05–0.025% (depending on the duration of treatment). The antigenicity analysis demonstrated that the antigen titre of the inactivated strain composition (1:16) was lower than that of native strains (1:32–1:64). The authors demonstrated comparability of immunogenicity profiles of the inacti­vated strain composition and native strains in mice.CONCLUSIONS. The study generated candidate rotavirus A strains that exhibited stable replica­tion in continuous cultures of Vero cells. The authors selected optimal inactivation conditions for these rotavirus strains and developed an inactivated strain composition showing antigenicity and immunogenicity. The presented data suggest that the composition of inactivated rotavirus A strains can be considered as a basis for further development of an inactivated rotavirus vaccine.

Abstract Biopesticides have received increasing global attention as environmentally friendly alternatives, allowing for more sustainable pest and disease control. In order to be registered or authorized for use, safety studies need to be submitted for regulatory risk assessments. However, it has been frequently reported that, in particular, microbial pesticides have a number of challenges when it comes to non-target organism testing. For instance, study results from such tests are often difficult to interpret or they lack consistency and accuracy. Reasons for this can be found firstly in the heterogeneity and resulting complexity of microbe-based pesticides comprising different taxonomic groups (e.g., bacteria, fungi, and viruses), and secondly in the lack of appropriate guidance for testing these different microbial agents considering their unique biological properties. The present review gives an overview of the available test guidelines by reflecting the current regulatory background in the area of environmental risk assessment of microbial pesticides and describes general and specific issues associated with safety studies on terrestrial vertebrates, aquatic organisms, bees, non-target arthropods other than bees, meso- and macro-organisms in soil, and non-target terrestrial plants. Proposals for improvement of existing test guidelines or guidance documents are provided and further discussed.

The main transmission route of bovine coronavirus (BCoV) is direct contact with secretions and feces, and potentially also via contaminated surfaces. Following PRISMA guidelines, a systematic review was conducted to evaluate the presence of BCoV on environmental surfaces. A literature search, conducted between March and April 2023, utilized databases including Web of Science, PubMed, Scopus, Science Direct, and Springer. The review adhered to the PEO structure: Population - environmental surfaces; Exposure - contact with BCoV; Outcome - identification of presence or infectivity. Primary data were recorded using an extraction form organizing methods for detecting BCoV presence, assessing BCoV infectivity, types of surfaces evaluated, and study type. Search terms “Bovine coronavirus” and “BCoV” yielded 2703 articles. After removing 964 duplicates and excluding 1546 articles not mentioning BCoV in titles, 193 studies underwent abstract reading. Following exclusion criteria not addressing BCoV presence in the environment, three articles were selected for comprehensive review. These articles identified BCoV presence on various types of surfaces, with detection possible up to 81 hours after contamination, depending on surface type. Despite limited studies on BCoV presence on surfaces, findings suggested potential transmission via contaminated surfaces due to the virus’s ability to remain infectious for up to 24 hours on fomites. This review underscores the need for further research on BCoV persistence in farm environments, an area currently lacking focused studies. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study was to explore the related factors linked to the development and infectivity of tuberculosis. This was achieved by comparing the clinical characteristics of patients with pulmonary tuberculosis (TB) who tested positive in smear Mycobacterium tuberculosis tests with this who tested negative in smear mycobacterium tests but positive in sputum Gene Xpert tests. We gathered clinical data of 1612 recently hospitalized patients diagnosed with pulmonary tuberculosis who tested positive either in sputum Gene-Xpert test or sputum smear Mycobacterium tuberculosis tests. The data was collected from January 1, 2018 to August 5, 2023, at Sichuan Provincial People's Hospital. We conducted separately analyzes and comparisons of the clinical characteristics between the two groups of patients, aiming to discussed the related factors influencing the development and infectivity of tuberculosis. In comparison to the GeneXpert positive group, the sputum smear positive group exhibited a higher proportion of elderly patients (aged 75–89) and individuals classified as underweight (BMI

Abstract Background Primaquine (PQ) has activity against mature P. falciparum gametocytes and proven transmission blocking efficacy (TBE) between humans and mosquitoes. WHO formerly recommended a single transmission blocking dose of 0.75 mg/kg but this was little used. Then in 2012, faced with the emergence of artemisinin-resistant P. falciparum (ARPf) in SE Asia, the WHO recommended a lower dose of 0.25 mg/kg to be added to artemisinin-based combination therapy in falciparum-infected patients in low transmission areas. This dose was considered safe in glucose-6-phosphate dehydrogenase deficiency (G6PDd) and not requiring G6PD testing. Subsequent single low-dose primaquine (SLDPQ) studies have demonstrated safety in different G6PD variants. Dosing remains challenging in children under the age of 5 because of the paucity of PQ pharmacokinetic (PK) data. We plan to assess the anti-infectivity efficacy of SLDPQ using an allometrically scaled, weight-based regimen, with a target dose of 0.25 mg/kg, in children with acute uncomplicated falciparum malaria. Methods This study is an open label, randomised 1:1, phase IIb study to assess TBE, tolerability, pharmacokinetics and acceptability of artesunate pyronaridine (ASPYR) administered alone or combined with SLDPQ in 56 Burkinabe children aged ≥ 6 months–

Hepatitis B infection is a common disease worldwide. Hepatitis B is one of the leading cause of malignancy and cirrhosis of liver. The diagnosis of Hepatitis B Virus (HBV) infection is mainly made through detection of serological markers. Our study aimed to detect presence of Hepatitis B Precore Antigen (HBeAg) and Antibodies to Hepatitis B core Antigen (HBcAg) among Hepatitis B Surface Antigen (HBsAg) positive samples detected in Microbiology laboratory during the study period. HBeAg, Total Anti HBc and Anti HBcIgM was detected using ELISA (DIA.PRO – ITALY) and patients were categorized based on presence of HBeAg, Total Anti HBc and Anti HBcIgM. Out of 180 samples tested positive for HBsAg, majority belonged to the age group of 41-60 years. With regard to gender, males were found to be majority and four percent were antenatal women. HBeAg was found in 20.6% patients indicating high infectivity. Out of 180 samples, 9.45% were found to have acute infection and 90.55% were with chronic infection. Among the patients with acute infection, 58.8% had high infectivity whereas in patients with chronic infection 16.56% had high infectivity. HBV Screening and categorization of positive patients are important to prevent chronic hepatitis, its complications among infected patients and to reduce the transmission of HBV in the community.

RESEARCH HIGHLIGHTSWe conducted research studies on avian reovirus (ARV) infectivity in egg-laying hens, focusing on three variants (δC genotypes 2, 3, and 5) detected in layer chickens in Pennsylvania to date. Day-old chicks (Hy-Line North America, LLC, PA), raised at the Poultry Education and Research Center of Penn State University Park campus, showed healthy growth and normal egg production after 20 weeks of age. ARV variants were propagated in Leghorn male-chicken hepatocellular-carcinoma cell cultures, with concentrations measured at TCID50/ml. Each group of 10 hens received a 1.0 ml dose containing 103–104 TCID50/ml of one ARV variant through oral, nasal, and ocular routes. Infected hens showed normal egg production, with minimal signs of watery droppings in the first-week post-inoculation (pi). Cloacal and oral pharyngeal swabs were collected daily in the first week pi and every other day in the second-week pi to monitor virus shedding. Virus shedding began 24 h pi through faeces, peaked at 2–4 days pi, decreased by 5–7 days pi, and ceased after 12–14 days pi. A few birds’ oral pharyngeal swabs were weakly positive for 1–3 days pi, then all turned negative. Infected hens developed high serum and egg yolk antibody titres at 2–3 weeks pi, showing 100% protection against subsequent infections with the same variant strain, demonstrating a 100% protection rate.Avian reovirus-infected hens shed virus heavily at 2–3 days post-inoculation.Shedding became minimal after 5–7 days post-inoculation.ARV variants offered 100% protection in hens upon subsequent infections.Infected hens maintained normal egg production with no observable clinical signs.Avian reovirus-infected hens shed virus heavily at 2–3 days post-inoculation.Shedding became minimal after 5–7 days post-inoculation.ARV variants offered 100% protection in hens upon subsequent infections.Infected hens maintained normal egg production with no observable clinical signs. [ABSTRACT FROM AUTHOR]

Hepatitis B Virus (HBV) infectivity data were reviewed and the 50% infectious dose (ID50) was reassessed in different HBsAg‐positive infection stages enabling modelling of transfusion‐transmitted (TT)‐HBV infection risk if HBsAg donor screening was replaced by individual donation nucleic acid amplification technology (ID‐NAT). Quantitative HBsAg and HBV‐DNA assays were performed against international standards to compare the ratio between potential infectious HBV virions and subviral HBsAg particles in Egyptian HBsAg‐positive blood donors as well as in Japanese chimpanzee samples of known infectivity. HBV‐DNA load below the quantification limit of detection was estimated against a reference standard by replicate NAT testing (n = 25). Infectivity of chimpanzee samples collected during ramp‐up and declining viremic phase were tested in a human liver chimeric mice (HLCM) model and compared with published infectivity data from different HBsAg‐positive infection stages. Lowest estimates of ID50 in HBsAg‐positive plasma were 3–6 HBV virions in chimpanzee studies. Infectivity decreased approximately 10‐100‐fold in the declining viremic phase using HLCM. In acute phase samples, HBV to HBsAg particle ratios varied between 1:102–104 but in HBsAg‐positive blood donors this particle ratio reached 1:106–1012 when viral load was below 100 HBV‐DNA copies/mL. Modelled TT‐HBV risk of an HBsAg‐positive/ID‐NAT nonreactive blood transfusion was estimated at 5.5%–27% for components containing 20–200 mL of plasma when assuming an ID50 of 316 (point estimate between 100 and 1000) virions. It cannot be ensured that discontinuation of HBsAg donor screening and reliance on ID‐NAT alone is safe. [ABSTRACT FROM AUTHOR]

The Env protein of murine leukemia virus (MLV) is the prototype of a large clade of retroviral fusogens, collectively known as gamma-type Envs. Gamma-type Envs are found in retroviruses and endogenous retroviruses (ERVs) representing a broad range of vertebrate hosts. All gamma-type Envs contain a highly conserved stretch of 26-residues in the transmembrane subunit (TM) comprising two motifs, a putative immunosuppressive domain (ISD) and a CX6CC motif. Extraordinary conservation of the ISD and its invariant association with the CX6CC suggests a fundamental contribution to Env function. To investigate ISD function, we characterized several mutants with single amino acid substitutions at conserved positions in the MLV ISD. A majority abolished infectivity, although we did not observe a corresponding loss in intrinsic ability to mediate membrane fusion. Ratios of the surface subunit (SU) to capsid protein (CA) in virions were diminished for a majority of the ISD mutants, while TM:CA ratios were similar to wild type. Specific loss of SU reflected premature isomerization of the labile disulfide bond that links SU and TM prior to fusion. Indeed, all non-infectious mutants displayed significantly lower disulfide stability than wild-type Env. These results reveal a role for ISD positions 2, 3, 4, 7, and 10 in regulating a late step in entry after fusion peptide insertion but prior to creation of the fusion pore. This implies that the ISD is part of a larger domain, comprising the ISD and CX6CC motifs, that is critical for the formation and regulation of the metastable, intersubunit disulfide bond. IMPORTANCE The gamma-type Env is a prevalent viral fusogen, found within retroviruses and endogenous retroviruses across vertebrate species and in filoviruses such as Ebolavirus. The fusion mechanism of gamma-type Envs is unique from other Class I fusogens such as those of influenza A virus and HIV-1. Gamma-type Envs contain a hallmark feature known as the immunosuppressive domain (ISD) that has been the subject of some controversy in the literature surrounding its putative immunosuppressive effects. Despite the distinctive conservation of the ISD, little has been done to investigate the role of this region for the function of this widespread fusogen. Our work demonstrates the importance of the ISD for the function of gamma-type Envs in infection, particularly in regulating the intermediate steps of membrane fusion. Understanding the fusion mechanism of gamma-type Envs has broad implications for understanding the entry of extant viruses and aspects of host biology connected to co-opted endogenous gamma-type Envs. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate the survival of Trichinella spiralis and T. pseudospiralis in decaying wild boar tissue and assess their freezing tolerance in experimentally infected animals. Methods: The present study was conducted in Buenos Aires City, Argentina during the 2018-2019 period. Two wild boars were used, one infected with 20,000 muscle larvae (ML) of T. spiralis and the other with T. pseudospiralis. Both animals were euthanized 19 weeks post-infection. Limbs from each boar were placed over soil in plastic containers to assess ML survival in decaying tissue, under natural temperature and humidity, shielded from rain. Weekly samples were taken for artificial digestion, and the ML were inoculated into mice to determine their reproductive capacity index (RCI). Additionally, to evaluate the freezing tolerance of the ML, muscle samples were stored at -18°C. Six samples were taken and digested after 2, 4, 7, 9, 11, and 14 days, with subsequent inoculation into mice to assess RCI. Results: T. spiralis remained infective in decaying wild boar tissue for 11 weeks, while T. pseudospiralis remained infective for only 4 weeks. The freezing tolerance assay showed that T. spiralis ML remain infective for 9 days. However, T. pseudospiralis ML remain infective for only 2 days at -18°C. Conclusion: The findings highlight the survival strategies of T. spiralis and T. pseudospiralis in different environmental conditions, which may have implications for understanding their transmission dynamics in wild animals. [ABSTRACT FROM AUTHOR]

Comprehending the replication kinetics of SARS-CoV-2 variants helps explain why certain variants spread more easily, are more contagious, and pose a significant health menace to global populations. The replication kinetics of the Malaysian isolates of Alpha, Beta, Delta, and Omicron variants were studied in the Vero E6 cell line. Their replication kinetics were determined using the plaque assay, quantitative real-time PCR (qRT-PCR), and the viral growth curve. The Beta variant exhibited the highest replication rate at 24 h post-infection (h.p.i), as evidenced by the highest viral titers and lowest viral RNA multiplication threshold. The plaque phenotypes also varied among the variants, in which the Beta and Omicron variants formed the largest and smallest plaques, respectively. All studied variants showed strong cytopathic effects after 48 h.p.i. The whole-genome sequencing highlighted cell-culture adaptation, where the Beta, Delta, and Omicron variants acquired mutations at the multibasic cleavage site after three cycles of passaging. The findings suggest a strong link between the replication rates and their respective transmissibility and pathogenicity. This is essential in predicting the impacts of the upcoming variants on the local and global populations and is useful in designing preventive measures to curb virus outbreaks. [ABSTRACT FROM AUTHOR]

Diverse bacterial and fungal microbiota communities inhabit the human body, and their presence is essential for maintaining host homeostasis. The oral cavity, lung, gut, and vagina are just a few of the bodily cavities where these microorganisms communicate with one another, either directly or indirectly. The effects of this interaction can be either useful or detrimental to the host. When the healthy microbial diversity is disturbed, for instance, as a result of prolonged treatment with broad spectrum antibiotics, this allows the growth of specific microbes at the expense of others and alters their pathogenicity, causing a switch of commensal germs into pathogenic germs, which could promote tissue invasion and damage, as occurs in immunocompromised patients. Consequently, antimicrobials that specifically target pathogens may help in minimizing secondary issues that result from the disruption of useful bacterial/fungal interactions (BFIs). The interface between Candida albicans and Aspergillus fumigatus with bacteria at various body sites is emphasized in the majority of the medically important BFIs that have been reported thus far. This interface either supports or inhibits growth, or it enhances or blocks the generation of virulence factors. The aim of this review is to draw attention to the link between the bacterial and fungal microbiota and how they contribute to both normal homeostasis and disease development. Additionally, recent research that has studied microbiota as novel antimicrobials is summarized. [ABSTRACT FROM AUTHOR]

Objective Analyzing the clinical and microbiological characteristics of coronavirus disease 2019 (COVID-19) infection in children seems essential to determine their role in the etiopathogenesis of the disease. Methods A prospective, longitudinal, and observational study, including children with severe acute respiratory syndrome coronavirus-2 infection, in the Barcelona Metropolitan Region (Spain), was performed. The recruitment pathways were: (1) children who attended a summer school and were included in an active surveillance study and (2) children who were visited in the Emergency Department of Hospital Sant Joan de Déu with symptoms. Close contacts with positive polymerase chain reaction (PCR) results were also included. The children recruited were followed up for 5 weeks. Evaluation of participants included a questionnaire for COVID-19 symptoms, nasopharyngeal swabbing for real-time PCR at 0, 7, and 14 days (weekly repeated up to week 5 if it resulted positive at 14 days), and serology testing at the recruitment and at the fifth week of follow-up. Results A total of 90 children were recruited, of which 32% were asymptomatic. Transmission was studied in 70/90 children, and in 12 cases (17%), transmission to other children or adults was observed. No clinical or epidemiological differences were found between children who transmitted and those who did not. At the end of the follow-up, 11% of nasopharyngeal PCR remained positive. The serological response was studied in 73/90 children, and 80.82% of children seroconverted. Conclusion No differences in epidemiological characteristics were found between children who transmitted and those who did not. PCR can be persistently positive for more than 5 weeks. The majority of patients who suffer from the disease produce antibodies against it. [ABSTRACT FROM AUTHOR]

Introduction: We compared the clinical characteristics of vaccinated and non-vaccinated Omicron patients in order to provide a reference for the clinical diagnosis and treatment of coronavirus disease 2019 (COVID-19). Methodology: This study included 360 patients diagnosed with COVID-19. The serum immunoglobulin G (IgG) and serum immunoglobulin M (IgM) antibody levels of the patients and the duration of virus shedding were analyzed according to age, gender, vaccine dose, and the time from the most recent vaccination to the onset of Omicron infection. Results: Age (OR = 0.974), days from last vaccination to onset ≤ 180 days (OR = 4.409), and booster dose of the vaccine (OR = 4.999) were protective factors associated with patients who were IgG antibody positive. The duration of virus shedding in IgG -antibody-positive patients was 9 (8-11) days; and this was significantly lower than that in IgG-antibody-negative patients, who had virus shedding duration of 10 (8-12) days (p < 0.05). Conclusions: Booster immunizations could increase IgG-antibody in patients who have already been infected with the Omicron variant and enhance immune protection. In addition, COVID-19 vaccination may shorten the duration of virus shedding. [ABSTRACT FROM AUTHOR]

Coxsackievirus B represents a nightmare for a large number of medical staff. Due to exposure to Coxsackievirus in closed spaces (ambulances and waiting rooms), infections by Coxsackievirus B are a common occurrence. This paper for the first time reports chemical and thermodynamic properties of Coxsackieviruses A and B, and offers a mechanistic model of Coxsackievirus-host interaction. The driving force of the interaction at the membrane (antigen-receptor binding) is Gibbs energy of binding. The driving force of virus-host interaction in the cytoplasm is Gibbs energy of biosynthesis. This paper analyzes the mechanism of hijacking of cell metabolic machinery of susceptible cells. [ABSTRACT FROM AUTHOR]

African Swine Fever (ASF) is a devastating viral hemorrhagic disease that causes high morbidity and mortality in domestic pigs and wild boars, severely impacting the swine industry. The etiologic agent, African Swine Fever virus (ASFV), mainly infects myeloid cells of the swine mononuclear phagocytic system (MPS). For other porcine viruses, in vitro culture models with primary cells are widely used as they mimic the in vivo viral replication behavior better compared to continuous cell lines. Our study validates this possible correlation for ASFV using cell culture models established for three different porcine macrophages, isolated from the lungs (porcine alveolar macrophages), blood (monocyte-derived macrophages) and spleen (spleen macrophages). The cells were infected with two genotype I and two genotype II strains with different pathogenic potential in vivo. The highly virulent strains replicated better in general than the low-virulent strains. This was most pronounced in monocyte-derived macrophages, although only statistically significant 18 h post-infection (hpi) in the intracellular genomic ASFV copies between E70 and the low-virulent strains. For this reason, we conclude that the different replication characteristics between the strains with different virulence do not proportionally represent the differences in pathology seen between the strains in vivo. Additionally, ASFV-positive cells were observed earlier in monocyte-derived macrophages (MDMs) compared to the alveolar and spleen macrophages, subsequently leading to an earlier rise in extracellular virus, and, ultimately, more MDMs were infected at the end of sampling. For these reasons, we propose MDMs as the best-suited cell type to study ASFV. [ABSTRACT FROM AUTHOR]

Background: Primaquine (PQ) has activity against mature P. falciparum gametocytes and proven transmission blocking efficacy (TBE) between humans and mosquitoes. WHO formerly recommended a single transmission blocking dose of 0.75 mg/kg but this was little used. Then in 2012, faced with the emergence of artemisinin-resistant P. falciparum (ARPf) in SE Asia, the WHO recommended a lower dose of 0.25 mg/kg to be added to artemisinin-based combination therapy in falciparum-infected patients in low transmission areas. This dose was considered safe in glucose-6-phosphate dehydrogenase deficiency (G6PDd) and not requiring G6PD testing. Subsequent single low-dose primaquine (SLDPQ) studies have demonstrated safety in different G6PD variants. Dosing remains challenging in children under the age of 5 because of the paucity of PQ pharmacokinetic (PK) data. We plan to assess the anti-infectivity efficacy of SLDPQ using an allometrically scaled, weight-based regimen, with a target dose of 0.25 mg/kg, in children with acute uncomplicated falciparum malaria. Methods: This study is an open label, randomised 1:1, phase IIb study to assess TBE, tolerability, pharmacokinetics and acceptability of artesunate pyronaridine (ASPYR) administered alone or combined with SLDPQ in 56 Burkinabe children aged ≥ 6 months– < 5 years, with uncomplicated P. falciparum and a haemoglobin (Hb) concentration of ≥ 5 g/dL. We will assess TBE, using direct membrane feeding assays (DMFA), and further investigate PQ pharmacokinetics, adverse events, Hb dynamics, G6PD, sickle cells, thalassaemia and cytochrome 2D6 (CYP2D6) status, acceptability of flavoured PQ [CAST—ClinSearch Acceptability Score Test®], and the population's knowledge, attitude and practices on malaria. Expected results and discussion: We expect children to accept tablets, confirm the TBE and gametocytocidal effects of SLDPQ and then construct a PK infectivity model (including age, sex, baseline Hb, G6PD and CYP2D6 status) to define the dose response TBE relationship that may lead to fine tuning our SLDPQ regimen. Our study will complement others that have examined factors associated with Hb dynamics and PQ PK. It will provide much needed, high-quality evidence of SLDPQ in sick African children and provide reassurance that SLDPQ should be used as a strategy against emerging ARPf in Africa. Trial registration: ISRCTN16297951. Registered on September 26, 2021 [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the related factors linked to the development and infectivity of tuberculosis. This was achieved by comparing the clinical characteristics of patients with pulmonary tuberculosis (TB) who tested positive in smear Mycobacterium tuberculosis tests with this who tested negative in smear mycobacterium tests but positive in sputum Gene Xpert tests. We gathered clinical data of 1612 recently hospitalized patients diagnosed with pulmonary tuberculosis who tested positive either in sputum Gene-Xpert test or sputum smear Mycobacterium tuberculosis tests. The data was collected from January 1, 2018 to August 5, 2023, at Sichuan Provincial People's Hospital. We conducted separately analyzes and comparisons of the clinical characteristics between the two groups of patients, aiming to discussed the related factors influencing the development and infectivity of tuberculosis. In comparison to the GeneXpert positive group, the sputum smear positive group exhibited a higher proportion of elderly patients (aged 75–89) and individuals classified as underweight (BMI < 18.5 kg/m2). Furthermore, this group was more prone to experiencing symptoms such as weight loss, coughing and sputum production, hemoptysis, shortness of breath, and difficulty breathing. Moreover, they are also more likely to develop extrapulmonary tuberculosis, such as tuberculous meningitis, tuberculous pleurisy, and tuberculous peritonitis. These clinical features, when present, not only increase the likelihood of a positive result in sputum smear tests but also suggest a high infectivity of pulmonary tuberculosis. Elderly individuals (aged 75 to 89) who are underweight (BMI < 18.5 kg/m2), display symptom of cough, expectoration, hemoptysis and dyspnea-particularly cough and expectoration-and those with extra pulmonary tuberculosis serve as indicators of highly infectious pulmonary tuberculosis patients. These patients may present with more severe condition, carrying a higher bacteria, and being more prone to bacterial elimination. Identification of these patients is crucial, and prompt actions such as timely and rapid isolation measures, cutting off transmission routes, and early empirical treatment of tuberculosis are essential to control the development of the disease. [ABSTRACT FROM AUTHOR]

Human norovirus is transmitted mainly via the faecal-oral route, but norovirus disease outbreaks have been reported in which airborne transmission has been suggested as the only explanation. We used murine norovirus (MNV) as a surrogate for human norovirus to determine the aerosolization of infectious norovirus in an experimental setup. A 3-l air chamber system was used for aerosolization of MNV. Virus in solution (6 log10 TCID50/ml) was introduced into the nebulizer for generating aerosols and a RAW 264.7 cell dish without a lid was placed in the air chamber. Cell culture medium samples were taken from the dishes after the aerosol exposure time of 30 or 90 min, and the dishes were placed in a 37 °C, 5% CO2 incubator and inspected with a light microscope for viral cytopathic effects (CPEs). We determined both the infectious MNV TCID50 titre and used an RT-qPCR assay. During the experiments, virus infectivity remained stable for 30 and 90 min in the MNV solution in the nebulizer. Infectious MNV TCID50 values/ml of 2.89 ± 0.29 and 3.20 ± 0.49 log10 were measured in the chamber in RAW 264.7 cell dish media after the 30-min and 90-min exposure, respectively. The MNV RNA loads were 6.20 ± 0.24 and 6.93 ± 1.02 log10 genome copies/ml, respectively. Later, a typical MNV CPE appeared in the aerosol-exposed RAW cell dishes. We demonstrated that MNV was aerosolized and that it remained infectious in the experimental setup used. Further studies required for understanding the behaviour of MNV in aerosols can thus be performed. [ABSTRACT FROM AUTHOR]

Hepatitis B infection is a common disease worldwide. Hepatitis B is one of the leading cause of malignancy and cirrhosis of liver. The diagnosis of Hepatitis B Virus (HBV) infection is mainly made through detection of serological markers. Our study aimed to detect presence of Hepatitis B Precore Antigen (HBeAg) and Antibodies to Hepatitis B core Antigen (HBcAg) among Hepatitis B Surface Antigen (HBsAg) positive samples detected in Microbiology laboratory during the study period. HBeAg, Total Anti HBc and Anti HBcIgM was detected using ELISA (DIA.PRO - ITALY) and patients were categorized based on presence of HBeAg, Total Anti HBc and Anti HBcIgM. Out of 180 samples tested positive for HBsAg, majority belonged to the age group of 41-60 years. With regard to gender, males were found to be majority and four percent were antenatal women. HBeAg was found in 20.6% patients indicating high infectivity. Out of 180 samples, 9.45% were found to have acute infection and 90.55% were with chronic infection. Among the patients with acute infection, 58.8% had high infectivity whereas in patients with chronic infection 16.56% had high infectivity. HBV Screening and categorization of positive patients are important to prevent chronic hepatitis, its complications among infected patients and to reduce the transmission of HBV in the community. [ABSTRACT FROM AUTHOR]

An unprecedented amount of SARS-CoV-2 data has been accumulated compared with previous infectious diseases, enabling insights into its evolutionary process and more thorough analyses. This study investigates SARS-CoV-2 features as it evolved to evaluate its infectivity. We examined viral sequences and identified the polarity of amino acids in the receptor binding motif (RBM) region. We detected an increased frequency of amino acid substitutions to lysine (K) and arginine (R) in variants of concern (VOCs). As the virus evolved to Omicron, commonly occurring mutations became fixed components of the new viral sequence. Furthermore, at specific positions of VOCs, only one type of amino acid substitution and a notable absence of mutations at D467 were detected. We found that the binding affinity of SARS-CoV-2 lineages to the ACE2 receptor was impacted by amino acid substitutions. Based on our discoveries, we developed APESS, an evaluation model evaluating infectivity from biochemical and mutational properties. In silico evaluation using real-world sequences and in vitro viral entry assays validated the accuracy of APESS and our discoveries. Using Machine Learning, we predicted mutations that had the potential to become more prominent. We created AIVE, a web-based system, accessible at https://ai-ve.org to provide infectivity measurements of mutations entered by users. Ultimately, we established a clear link between specific viral properties and increased infectivity, enhancing our understanding of SARS-CoV-2 and enabling more accurate predictions of the virus.

Objectives We analyzed the correlation between the infectivity and transmissibility of the severe acute respiratory syndrome coronavirus 2 Omicron sublineages BA.1, BA.2, BA.4, and BA.5. Methods We assessed viral replication kinetics and infectivity at the cellular level. Nasopharyngeal and oropharyngeal specimens were obtained from patients with coronavirus disease 2019, confirmed using whole-genome sequencing to be caused by the Omicron sublineages BA.1, BA.2, BA.4, or BA.5. These specimens were used to infect Vero E6 cells, derived from monkey kidneys, for the purpose of viral isolation. Viral stocks were then passaged in Vero E6 cells at a multiplicity of infection of 0.01, and culture supernatants were harvested at 12-hour intervals for 72 hours. To evaluate viral replication kinetics, we determined the cycle threshold values of the supernatants using real-time reverse transcription polymerase chain reaction and converted these values to genome copy numbers. Results The viral load was comparable between BA.2, BA.4, and BA.5, whereas BA.1 exhibited a lower value. The peak infectious load of BA.4 was approximately 3 times lower than that of BA.2 and BA.5, while the peak load of BA.2 and BA.5 was about 7 times higher than that of BA.1. Notably, BA.1 demonstrated the lowest infectivity over the entire study period. Conclusion Our results suggest that the global BA.5 wave may have been amplified by the higher viral replication and infectivity of BA.5 compared to other Omicron sublineages. These analyses could support the rapid assessment of the impact of novel variants on case incidence.

Semi-covariance has attracted significant attention in recent years and is increasingly employed to elucidate statistical phenomena exhibiting fluctuations, such as the similarity or difference in charge patterns of spike proteins among coronaviruses. In this study, by examining values above and below the average/mean based on the positive and negative charge patterns of amino acid residues in the spike proteins of SARS-CoV-2 and its current circulating variants, the proposed methods offer profound insights into the nonlinear evolving trends in those viral spike proteins. Our study indicates that the charge span value can predict the infectivity of the virus and the charge density can estimate the virulence of the virus, and both predicated infectivity and virulence appear to be associated with the capability of viral immune escape. This semi-covariance coefficient analysis may be used not only to predict the infectivity, virulence and capability of immune escape for coronaviruses but also to analyze the functionality of other viral proteins. This study improves our understanding of the trend of viral evolution in terms of viral infectivity, virulence or the capability of immune escape, which remains further validated by more future studies and statistical data. [ABSTRACT FROM AUTHOR]

The emergence of new viruses into human populations is one of the major challenges in the coming decades. The COVID-19 crisis was an intense reminder. Environmental perspective of SARS-CoV-2 as an emerging viruses is at the focus of many studies. Multiple investigations have shown the presence of the virus in the excrement of an individual who is infected, even during an extended duration of medical intervention. This review aims to understand the destiny of SARS-CoV-2 in various environments with respect to its occurrence, persistence and elimination based on the papers published so far. The SARS-Co2 virus was isolated from contaminated water and rivers, but there is insufficient evidence for viral transmission via water and wastewater. To date, few studies have confirmed the infectivity of SARS-CoV-2 due to cell culture infectivity assay results. Furthermore, some studies have investigated the elimination of SARS-CoV-2 in different stages of wastewater treatment plants (WWTPs). High inactivation in WWTPs can be completed using efficient disinfectants. There have been no recorded instances of the transmission of this virus to individuals through sewage up until now. Nevertheless, research findings have demonstrated the importance of wastewater monitoring in the early detection of the virus variants in communities. There is a need for constant surveillance of emerging viral diseases in all countries around the world. Wastewater surveillance can serve as an initial evaluation of viral infection within a community in the case of SARS-CoV-2. [ABSTRACT FROM AUTHOR]

The high objectives to this study were to determine and evaluate incidence of Sarcocystis fusiform infection in slaughtered buffaloes in Assiut abattoir, and additionally study the effect of chilling on their viability and infectivity. Tissue specimens were collected from three hundred and fifty-six buffaloes (337 male buffaloes and 19 female buffaloes) slaughtered at Assiut abattoir during the period from 2/2022 to 1/2023. Samples including esophagus, tongue, and masseter muscles were examined macroscopically and histopathologically. The total prevalence of macroscopic Sarcocystis (S. fusiform) in examined buffaloes was 8.43%, the infection rate in males (Less than 2 years) and in females buffaloes (4 to 7 years old) were (8.3%) and (10.53%), respectively. The predilection seats of S. fusiform in examined buffaloes were; esophagus (90%), followed by tongue (23.3%), throat muscles (20%) and the lowest one skeletal muscle (total body) (3.3%). Concerning seasonal variation the high infection rate was happened and detected in spring (13.9%) while the lowest infection was happened in the autumn season (5.4%). The effect of chilling on the viability of S. fusiform cysts was investigated using a vital stain (0.4% trypan blue). Heavily infected muscles were chilled at 4°C for 24, 48 and 72h and was carried out on cats. The reduction rate of S. fusiformis bradyzoites after chilling was (0%), (20%) and (54.6%), respectively. However, the parasite lost its infectivity after chilling for three days, where heavily infected muscles cooling at 4°C were rendered non-infective to cats. Conclusion: The present study concluded that S. fusiformis infection in buffaloes constitutes one of the main causes of economic losses in Assiut slaughterhouses. The incidence of S. fusiform was higher in aged female buffaloes and esophagus was the main predilection seat. Additionally, our results showed that cooling heavily infected muscles with S. fusiformis at 4 °C leads to a significant reduction that touched as a fact in parasite viability and trypan blue stain effectively measured the viability of Sarcocystis. Also, the infectivity of the parasite to cats was lost after chilling for three days. [ABSTRACT FROM AUTHOR]

In a previous study to understand how the chikungunya virus (CHIKV) E1 glycoprotein β-strand c functions, we identified several attenuating variants at E1 residue V80 and the emergence of second-site mutations in the fusion loop (E1-M88L) and hinge region (E1-N20Y) with the V80 variants in vivo. The emergence of these mutations led us to question how changes in E1 may contribute to CHIKV infection at the molecular level. Here, we use molecular dynamics to understand how changes in the E1 glycoprotein may influence the CHIKV glycoprotein E1-E2 complex. We found that E1 domain II variants lead to E2 conformational changes, allowing us to hypothesize that emerging variants E1-M88L and E1-N20Y could also change E2 conformation and function. We characterized CHIKV E1-M88L and E1-N20Y in vitro and in vivo to understand how these regions of the E1 glycoprotein contribute to host-specific infection. We found that CHIKV E1-N20Y enhanced infectivity in mosquito cells, while the CHIKV E1-M88L variant enhanced infectivity in both BHK-21 and C6/36 cells and led to changes in viral cholesterol-dependence. Moreover, we found that E1-M88L and E1-N20Y changed E2 conformation, heparin binding, and interactions with the receptor Mxra8. Interestingly, the CHIKV E1-M88L variant increased replication in Mxra8-deficient mice compared to WT CHIKV, yet was attenuated in mouse fibroblasts, suggesting that residue E1-M88 may function in a cell-type-dependent entry. Taken together, these studies show that key residues in the CHIKV E1 domain II and hinge region function through changes in E1-E2 dynamics to facilitate cell- and host-dependent entry. IMPORTANCE Arboviruses are significant global public health threats, and their continued emergence around the world highlights the need to understand how these viruses replicate at the molecular level. The alphavirus glycoproteins are critical for virus entry in mosquitoes and mammals, yet how these proteins function is not completely understood. Therefore, it is critical to dissect how distinct glycoprotein domains function in vitro and in vivo to address these gaps in our knowledge. Here, we show that changes in the CHIKV E1 domain II and hinge alter E2 conformations leading to changes in virus-receptor and -glycosaminoglycan interactions and cell-specific infection. These results highlight that adaptive changes in E1 can have a major effect on virus attachment and entry, furthering our knowledge of how alphaviruses infect mammals and insects. [ABSTRACT FROM AUTHOR]

Human cytomegalovirus (HCMV) displays a broad cell tropism, and the infection of biologically relevant cells such as epithelial, endothelial, and hematopoietic cells supports viral transmission, systemic spread, and pathogenesis in the human host. HCMV strains differ in their ability to infect and replicate in these cell types, but the genetic basis of these differences has remained incompletely understood. In this study, we investigated HCMV strain VR1814, which is highly infectious for epithelial cells and macrophages and induces cell-cell fusion in both cell types. A VR1814-derived bacterial artificial chromosome (BAC) clone, FIX-BAC, was generated many years ago but has fallen out of favor because of its modest infectivity. By sequence comparison and genetic engineering of FIX, we demonstrate that the high infectivity of VR1814 and its ability to induce syncytium formation in epithelial cells and macrophages depends on VR1814-specific variants of the envelope glycoproteins gB, UL128, and UL130. We also show that UL130-neutralizing antibodies inhibit syncytium formation, and a FIX-specific mutation in UL130 is responsible for its low infectivity by reducing the amount of the pentameric glycoprotein complex in viral particles. Moreover, we found that a VR1814- specific mutation in US28 further increases viral infectivity in macrophages, possibly by promoting lytic rather than latent infection of these cells. Our findings show that variants of gB and the pentameric complex are major determinants of infectivity and syncytium formation in epithelial cells and macrophages. Furthermore, the VR1814-adjusted FIX strains can serve as valuable tools to study HCMV infection of myeloid cells. IMPORTANCE Human cytomegalovirus (HCMV) is a major cause of morbidity and mortality in transplant patients and the leading cause of congenital infections. HCMV infects various cell types, including epithelial cells and macrophages, and some strains induce the fusion of neighboring cells, leading to the formation of large multinucleated cells called syncytia. This process may limit the exposure of the virus to host immune factors and affect pathogenicity. However, the reason why some HCMV strains exhibit a broader cell tropism and why some induce cell fusion more than others is not well understood. We compared two closely related HCMV strains and provided evidence that small differences in viral envelope glycoproteins can massively increase or decrease the virus infectivity and its ability to induce syncytium formation. The results of the study suggest that natural strain variations may influence HCMV infection and pathogenesis in humans. [ABSTRACT FROM AUTHOR]

Various SARS-CoV-2-related coronaviruses have been increasingly identified in pangolins, showing a potential threat to humans. Here we report the infectivity and pathogenicity of the SARS-CoV-2-related virus, PCoV-GX/P2V, which was isolated from a Malayan pangolin (Manis javanica). PCoV-GX/P2V could grow in human hepatoma, colorectal adenocarcinoma cells, and human primary nasal epithelial cells. It replicated more efficiently in cells expressing human angiotensin-converting enzyme 2 (hACE2) as SARS-CoV-2 did. After intranasal inoculation to the hACE2-transgenic mice, PCoV-GX/P2V not only replicated in nasal turbinate and lungs, but also caused interstitial pneumonia, characterized by infiltration of mixed inflammatory cells and multifocal alveolar hemorrhage. Existing population immunity established by SARS-CoV-2 infection and vaccination may not protect people from PCoV-GX/P2V infection. These findings further verify the hACE2 utility of PCoV-GX/P2V by in vivo experiments using authentic viruses and highlight the importance for intensive surveillance to prevent possible cross-species transmission. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is a zoonotic parasite with global distribution capable of infecting homeothermic animals. Transmission of protozoan to humans includes ingestion of water and raw food contaminated with sporulated oocysts, ingestion of raw or undercooked meat with tissue cysts, and tachyzoites' transplacental transmission. Fresh goat milk intake has already been linked to human toxoplasmosis outbreaks, but little is known about the infectious potential of this biological sample. Accordingly, the aim of the present study is to assess the survival and infectivity of T. gondii tachyzoites in fresh goat milk samples through an experimental protocol to detect this parasite via bioassay carried out with a murine model, DNA amplification, and serology. Swiss Webster mice were inoculated with fresh goat milk samples contaminated with different T. gondii RH strain tachyzoite concentrations per milliliter and stored for different refrigeration times. Animals showing clinical signs compatible to toxoplasmosis were euthanized. Milk samples contaminated with high parasitic loads and kept for a shorter refrigeration time were the most lethal ones. No significant differences were observed between mean death rates recorded for different goat milk contamination concentrations (p = 0.1888), and for the refrigeration time, contaminated milk samples were kept under (p = 0.9440). T. gondii DNA was amplified in all contaminated milk samples, but only one of the surviving mice was serologically positive. Results of the present study have shown T. gondii survival and infectivity in fresh goat milk samples, and it highlights its significant risk for public health. Therefore, molecular methods must be the tests of choice when milk samples are used to assess infection caused by protozoan in goats' dairy products. [ABSTRACT FROM AUTHOR]

Potato virus Y (PVY) is one of the most important constraints to potato production worldwide. There is an increasing occurrence of recombinant PVY strains PVYNTN and PVYN-Wi and a decline in the incidence of the nonrecombinant PVYO. We hypothesized that this may be due to the ability of these recombinant strains to antagonize and/or outcompete PVYO in mixed infections. To determine this, we investigated interactions between PVYO and three recombinant PVY strains common in North America: PVYNTN, PVYN-Wi, and PVYN:O. Overall, our study showed that these interactions are tissue-dependent. Specifically, PVYNTN, the main causal agent of potato tuber necrotic ringspot disease (PTNRD), was found to be more adaptable than PVYO, especially in potato leaves due, at least in part, to the Ny gene that confers hypersensitive resistance (HR) to PVYO. Furthermore, PVYN-Wi was found to repress PVYO in potato tubers but act synergistically in potato leaves. The PVYO-induced foliage necrosis in cultivar 'Ranger Russet' was observed to be more severe in plants co-infected by PVYN-Wi and PVYN:O, respectively, resulting in plant death. Strikingly, this PVYO -induced necrosis was suppressed by PVYNTN in doubly infected plants. These interactions may, at least partially, explain the decreasing incidence of PVYO in United States potato production regions, especially given that many cultivars contain the Ny gene, which likely limits PVYO enabling PVYNTN and PVYN-Wi to outcompete. We also found that replication and cell-to-cell movement of these PVY strains in tubers at 4 °C was similar to levels at ambient temperature. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate the survival of Trichinella spiralis and T. pseudospiralis in decaying wild boar tissue and assess their freezing tolerance in experimentally infected animals. Methods: The present study was conducted in Buenos Aires City, Argentina during the 2018-2019 period. Two wild boars were used, one infected with 20,000 muscle larvae (ML) of T. spiralis and the other with T. pseudospiralis. Both animals were euthanized 19 weeks post-infection. Limbs from each boar were placed over soil in plastic containers to assess ML survival in decaying tissue, under natural temperature and humidity, shielded from rain. Weekly samples were taken for artificial digestion, and the ML were inoculated into mice to determine their reproductive capacity index (RCI). Additionally, to evaluate the freezing tolerance of the ML, muscle samples were stored at -18°C. Six samples were taken and digested after 2, 4, 7, 9, 11, and 14 days, with subsequent inoculation into mice to assess RCI. Results: T. spiralis remained infective in decaying wild boar tissue for 11 weeks, while T. pseudospiralis remained infective for only 4 weeks. The freezing tolerance assay showed that T. spiralis ML remain infective for 9 days. However, T. pseudospiralis ML remain infective for only 2 days at -18°C. Conclusion: The findings highlight the survival strategies of T. spiralis and T. pseudospiralis in different environmental conditions, which may have implications for understanding their transmission dynamics in wild animals.

Objective: To characterize the infection patterns and growth characteristics of the Zika virus (ZIKV) strain JMB-185 from Indonesia in various mammalian cell lines. Methods: ZIKV was grown in human (A549, HEK293, HepG2, Huh7, Jurkat, and THP-1) and non-human mammalian (RAW264.7, Vero, and Vero76) cell lines. Viral replication kinetics were measured using plaque assay, while intra- and extracellular viral RNA concentrations were assessed using RT-PCR. Flow cytometry was used to quantify the infected cells and cell viability was measured using an MTT assay. The ability of ZIKV to infect cell lines was visualized using a fluorescence immunostaining assay. Results: This ZIKV strain preferentially infected the lung, kidney, and liver cell lines A549, HEK293, Huh7, Vero, and Vero76, but not the immune cells Jurkat, RAW264.7, and THP-1. By contrast, the ZIKV showed no sign of infection in HepG2 cells, while maintaining viral titer over 3 days post-infection, with no infection recorded in immunostaining, no increase in viral RNA, and no indication of cell deterioration. Conclusions: The Indonesian ZIKV strain has a similar infection profile as other strains, except for its poor infectivity on HepG2 cells. Information on the growth characteristics of Indonesia ZIKV will help expand our understanding of the biology of ZIKV which will be useful for various applications including antiviral discovery.

Meloidogyne hapla is a serious pest of many cultivated plants. In response to the economic significance of the species, efforts are being made to develop a new method to reduce its harmful effects on crops. The aim of the study was to determine the effect of diffusates from seeds of selected species of legumes on the motility of second-stage juveniles and to evaluate the effect of meal from seeds of selected species of legume on the capacity to infect the roots of tomato plants by the J2 stage. The experiment examined the effect of diffusates on the motility of the J2 stage performed in Petri dishes, at temperatures of 10 °C, 17 °C and 21 °C. The evaluation of the J2 stage infectivity was estimated in a pot experiment performed under controlled conditions of 20 ± 1 °C. The pots were filled with sterile substrate mixed with meal from the seeds of selected plants at 1%, 5% and 10% of the substrate weight. The studies carried out in the Petri dishes showed varying effects of the seed diffusates from selected legume plants on the motility of the J2 stage of Meloidogyne hapla. J2 were found to lose their motility within 24 h after immersion in water containing seed diffusates from Melilotus albus, Trifolium pratense T. repens, in the temperature ranges investigated (10 °C, 17 °C and 21 °C). However, in a mixture of seed diffusates and soil filtrate from the root zone of tomato plants, the absence of motility in the second-stage juveniles was observed after 24 h at 17 °C and 21 °C, with seed diffusates from Lotus corniculatus, Medicago sativa, Medicago × varia, Melilotus officinalis, as well as Onobrychis viciifolia, Ornithopus sativus, Vicia sativa, used in the mixture. Galega officinalis Risa (GoR) seed diffusates were found to have an inhibiting effect on the motility of the J2 stage of M. hapla 24 h following the immersion of the J2 stage in the solution of the soil filtrate containing tomato root diffusates, at 21 °C. The J2 stage were not rendered immotile in all the experiment set-ups involving the seeds of V. faba, Lupinus spp., likewise in the control set-ups. In the pots studied, a significant effect of the addition of legume seed meal on the development of M. hapla nematodes and tomato plants was found. The introduction of Lotus corniculatus, Onobrychis viciifolia and Vicia sativa seed meal into the substrate in the proportion of 1%, 5% and 10% resulted in the inhibition of the J2 stage penetration into the roots of tomato plants at temperatures of 17 °C and 21 °C. With the admixture of the M. sativa and T. repens seed meal, within the temperature range investigated, no nematode infection was observed in the roots, regardless of the seed meal content in the substrate. As regards to the fresh weight, tomato plants grown in a substrate containing 1% and 5% of the V. sativa cv. Jaga seed meal were characterised by significantly higher plant weight values as compared to those grown in the control set-up. The obtained results imply that is advisable to expand the scope of research to include other economically important crops damaged by the northern root-knot nematode.