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Objectives In May 2018, a laboratory network for antimicrobial resistance (AMR) surveillance in Tamil Nadu, India, detected a cluster of Salmonella enterica serotype Typhi (S. Typhi) isolates resistant to ceftriaxone. We investigated to describe the epidemiology and identify risk factors for the outbreak. Methods We conducted unmatched case-control studies. We defined a case as illness (fever with abdominal pain, diarrhea or vomiting) in a person with blood culture-confirmed ceftriaxone-resistant S. Typhi isolated between January 1 and July 4, 2018 in Tiruchirappalli, Tamil Nadu. We interviewed cases using a semi-structured questionnaire to identify common exposures to food, water and places visited. Results We identified 7 cases (5 men) during March 25–June 8, 2018, median age 23 years (range: 12–42); all were hospitalized, none died. Eating at Restaurant A (odds ratio [OR]=22) and chicken gravy (OR=16) was associated with illness. Of the 10 workers at Restaurant A, stool culture from 8 did not detect S. Typhi; 2 did not consent to provide samples. Five water samples around the restaurant showed low or no residual chlorine content. Conclusions The investigation highlights the value of AMR surveillance in detecting emerging pathogens and the need for timely investigations, along with strengthening food safety. more...

Summary Background The COVID-19 pandemic and efforts to reduce SARS-CoV-2 transmission substantially affected health services worldwide. To better understand the impact of the pandemic on childhood routine immunisation, we estimated disruptions in vaccine coverage associated with the pandemic in 2020, globally and by Global Burden of Disease (GBD) super-region. Methods For this analysis we used a two-step hierarchical random spline modelling approach to estimate global and regional disruptions to routine immunisation using administrative data and reports from electronic immunisation systems, with mobility data as a model input. Paired with estimates of vaccine coverage expected in the absence of COVID-19, which were derived from vaccine coverage models from GBD 2020, Release 1 (GBD 2020 R1), we estimated the number of children who missed routinely delivered doses of the third-dose diphtheria-tetanus-pertussis (DTP3) vaccine and first-dose measles-containing vaccine (MCV1) in 2020. Findings Globally, in 2020, estimated vaccine coverage was 76·7% (95% uncertainty interval 74·3–78·6) for DTP3 and 78·9% (74·8–81·9) for MCV1, representing relative reductions of 7·7% (6·0–10·1) for DTP3 and 7·9% (5·2–11·7) for MCV1, compared to expected doses delivered in the absence of the COVID-19 pandemic. From January to December, 2020, we estimated that 30·0 million (27·6–33·1) children missed doses of DTP3 and 27·2 million (23·4–32·5) children missed MCV1 doses. Compared to expected gaps in coverage for eligible children in 2020, these estimates represented an additional 8·5 million (6·5–11·6) children not routinely vaccinated with DTP3 and an additional 8·9 million (5·7–13·7) children not routinely vaccinated with MCV1 attributable to the COVID-19 pandemic. Globally, monthly disruptions were highest in April, 2020, across all GBD super-regions, with 4·6 million (4·0–5·4) children missing doses of DTP3 and 4·4 million (3·7–5·2) children missing doses of MCV1. Every GBD super-region saw reductions in vaccine coverage in March and April, with the most severe annual impacts in north Africa and the Middle East, south Asia, and Latin America and the Caribbean. We estimated the lowest annual reductions in vaccine delivery in sub-Saharan Africa, where disruptions remained minimal throughout the year. For some super-regions, including southeast Asia, east Asia, and Oceania for both DTP3 and MCV1, the high-income super-region for DTP3, and south Asia for MCV1, estimates suggest that monthly doses were delivered at or above expected levels during the second half of 2020. Interpretation Routine immunisation services faced stark challenges in 2020, with the COVID-19 pandemic causing the most widespread and largest global disruption in recent history. Although the latest coverage trajectories point towards recovery in some regions, a combination of lagging catch-up immunisation services, continued SARS-CoV-2 transmission, and persistent gaps in vaccine coverage before the pandemic still left millions of children under-vaccinated or unvaccinated against preventable diseases at the end of 2020, and these gaps are likely to extend throughout 2021. Strengthening routine immunisation data systems and efforts to target resources and outreach will be essential to minimise the risk of vaccine-preventable disease outbreaks, reach children who missed routine vaccine doses during the pandemic, and accelerate progress towards higher and more equitable vaccination coverage over the next decade. Funding Bill & Melinda Gates Foundation. more...

We report a diphtheria outbreak mostly among children (median 12 years; range 4-26 years) of a religious minority in urban India. Case-fatality rate (15%, 19/124) was higher among unimmunized patients (relative risk 4.1, 95% CI 1.5-11.7). We recommend mandating and integrating immunization into school health programs to prevent reemergence. more...

Background In 2016, India reported 709 acute diarrheal disease (ADD) outbreaks (> 25% of all outbreaks). Tribal populations are at higher risk with 27% not having accessibility to safe drinking water and 75% households not having toilets. On June 26, 2017 Pedda-Gujjul-Thanda, a tribal village reported an acute diarrheal disease (ADD) outbreak. We investigated to describe the epidemiology, identify risk factors, and provide evidence-based recommendations. Methods We defined a case as ≥3 loose stools within 24 h in Pedda-Gujjul-Thanda residents from June 24–30, 2017. We identified cases by reviewing hospital records and house-to-house survey. We conducted a retrospective cohort study and collected stool samples for culture. We assessed drinking water supply and sanitation practices and tested water samples for faecal-contamination. Results We identified 191 cases (65% females) with median age 36 years (range 4–80 years) and no deaths. The attack-rate (AR) was 37% (191/512). Downhill colonies (located on slope of hilly terrains of the village) reported higher ARs (56%[136/243], p Vibrio cholerae. Heavy rainfall was reported from June 22–24. Five of six water samples collected from shallow bore-wells located in downhill colonies were positive for faecal contamination. Conclusion An ADD outbreak with high attack rate in a remote tribal village was associated with drinking water from shallow downhill bore-wells, likely contaminated via runoff from open defecation areas after heavy rains. Based on our recommendations, immediate public health actions including repair of leakages at contaminated water sources and alternative supply of purified canned drinking water to families, and as long-term public health measures construction of house-hold latrines and piped-water supply initiated. more...

Background: Acute diarrheal disease (ADD) outbreaks frequently occur in the Gangetic plains of Uttar Pradesh, India. In August 2017, Muzaffarpur village, Uttar Pradesh, reported an ADD outbreak. Objectives: Outbreak investigation was conducted to find out the epidemiology and to identify the risk factors. Methods: A 1:1 area-matched case–control study was conducted. Suspected ADD case was defined as ≥3 loose stools or vomiting within 24 h in a Muzaffarpur resident between August 7 and September 9, 2017. A control was defined as an absence of loose stools and vomiting in a resident between August 7 and September 9, 2017. A matched odds ratio (mOR) with 95% confidence intervals (CIs) was calculated. Drinking water was assessed to test for the presence of any contamination. Stool specimens were tested for Vibrio cholerae, and water samples were also tested for any fecal contamination and residual chlorine. Results: Among 70 cases (female = 60%; median age = 12 years, range = 3 months–70 years), two cases died and 35 cases were hospitalized. Area–A in Muzaffarpur had the highest attack rate (8%). The index case washed soiled clothes at well – A1 1 week before other cases occurred. Among 67 case–control pairs, water consumption from well–A1 (mOR: 43.00; 95% CI: 2.60–709.88) and not washing hands with soap (mOR: 2.87; 95% CI: 1.28–6.42) were associated with illness. All seven stool specimens tested negative for V. cholerae. All six water samples, including one from well–A1, tested positive for fecal contamination with more...

Background: Acute diarrheal disease (ADD) accounts for 12 million cases and 1216 deaths annually in India. On July 13, 2016, an ADD outbreak was reported from Sawargaon village from Nagpur district, Maharashtra. Objective: The outbreak was investigated to describe the epidemiology and suggest control and preventive measures. Methods: A case was defined as a person experiencing at least one loose stool in Sawargaon village between July 9, 2016, and July 31, 2016. We searched for cases by enhanced passive surveillance. We collected stool samples for bacterial culture and tested water from multiple water sources for fecal coliforms. We also reviewed sanitary practices and rainfall data. Results: A total of 889 cases were identified, with 51% female, 280 hospitalizations (31%), and two deaths. The median age was 27 years (range 6 months to 90 years). Cases started on July 9, a week after heavy rains. District authorities started chlorination of water sources on July 13 and cases declined soon after. Two of nine stool samples tested positive for Vibrio cholera O1 serogroup. Of the 18 water samples collected, 16 (88%) samples from multiple sources, including wells, hand pumps, and taps, were positive for fecal coliforms. Of 1,885 households in the village, 450 (24%) households had no toilets and open defecation was commonly observed in the nearby river bed. Conclusions: This ADD outbreak was likely associated with drinking contaminated groundwater, which probably occurred after heavy rainfall in an area of open defecation. We recommended providing chlorinated drinking water, promoting safe sanitation practices, including building more public and private toilets, and enhancing diagnostic laboratory capacity. more...

Background: Of 1115 measles outbreaks during 2015 in India, 61,255 suspected measles cases were reported. In 2016, a measles outbreak was reported at East and West Jaintia Hills districts in Meghalaya State, India. Objectives: The outbreak was investigated to describe the epidemiology, estimate vaccination coverage and vaccine effectiveness (VE), determine risk factors for the disease, and recommend control and prevention measures. Methods: A measles case was defined as new-onset fever with maculopapular rash occurring between May 1, 2016, and January 21, 2017, in a resident of East and West Jaintia Hills. Cases were identified by active and passive surveillance. Serum and urine samples were collected from cases with laboratory diagnosis for confirmation. A retrospective cohort study was conducted to estimate vaccination coverage, VE, and risk factors for the disease. Results: We identified 382 cases (51% female). The attack rate was 24% with three deaths. The case fatality rate was more...

Background: The SARS-CoV-2 pandemic has revealed the vulnerability of immunization systems worldwide, although the scale of these disruptions has not been described at a global level. Methods: This report synthesized data representing 169 countries and territories. Data sources included administered vaccine dose data from January-December 2019 and 2020, WHO Regional office reports, and the WHO-led pulse survey administered in April and June 2020. Results were expressed as frequencies and proportions of respondents or reporting countries. Vaccine doses administered data were weighted by the population of surviving infants per country. Findings: A decline in the number of DTP3 and MCV1 doses administered in the first half of 2020 was noted. The nadir was observed in April 2020, when 35% fewer DTP3 doses were administered globally, ranging from 10% in Africa to 58% in South East Asia. Recovery of vaccinations began by June 2020 and continued into late 2020. WHO regional offices reported significant disruption to routine vaccination sessions in April 2020, related to interrupted vaccination demand, and supply, including reduced availability of the health workforce. Pulse survey analysis revealed that 69% of countries experienced disruption in outreach services compared to 44% countries with disrupted fixed-post immunization services. Interpretation: The marked magnitude and global scale of immunization disruption evokes the dangers of vaccine-preventable disease outbreaks in the future. Trends indicating partial resumption of services highlight the urgent need for ongoing assessment of recovery, catch-up vaccination strategy implementation for vulnerable populations, and ensuring vaccine coverage equity and health system resilience. Funding: World Health Organization and U.S. Agency for International Development (USAID). Conflict of Interest: We declare no competing interests. more...

Background: The COVID-19 pandemic has contributed to a widespread disruption of immunization services, including the suspension of mass vaccination campaigns. Methods: In May 2020, the World Health Organization (WHO) and partners established an Immunization Repository Campaign Delay Tracker to document the COVID-19 related disruptions to preventive and outbreak response vaccination campaigns worldwide of nine vaccines. Data were collected from disease specific initiatives that provided programme information to WHO Headquarters and reported through the Polio Information System (POLIS). Using these data, the authors reviewed the number of vaccination campaigns that were scheduled, postponed, cancelled and reinstated at three timepoints: May 2020, December 2020 and May 2021. Findings: The results indicate that mass vaccination campaigns across all vaccines were disrupted heavily by COVID-19. In May 2020, 105 of 183 (57%) campaigns were postponed or cancelled in 57 countries due to COVID-19, which resulted in an estimated 796 million postponed or missed vaccine doses. Campaign resumption was observed beginning in July 2020. By May 2021, 56% (72 of 128) postponed campaigns had been reinstated after an initial postponement due to COVID-19. However, 79 campaigns in 53 countries were still postponed or cancelled due to COVID-19, which resulted in an estimated 390 million postponed or missed vaccine doses. Interpretation: Our findings suggest a high risk of an increased number of persons susceptible to vaccine-preventable diseases during the pandemic due to mass vaccination campaign postponement. Implementing safe, aggressive and innovative catch-up vaccination strategies is needed to prevent sizeable vaccine-preventable disease outbreaks resulting from these accumulated immunity gaps. Funding Information: This study is not supported by any funder. Declaration of Interests: We declare no competing interests. more...

Background Cutaneous anthrax in humans is associated with exposure to infected animals or animal products and has a case fatality rate of up to 20% if untreated. During May to June 2015, an outbreak of cutaneous anthrax was reported in Koraput district of Odisha, India, an area endemic for anthrax. We investigated the outbreak to identify risk factors and recommend control measures. Method We defined a cutaneous anthrax case as skin lesions (e.g., papule, vesicle or eschar) in a person residing in Koraput district with illness onset between February 1 and July 15, 2015. We established active surveillance through a house to house survey to ascertain additional cases and conducted a 1:2 unmatched case control study to identify modifiable risk factors. In case control study, we included cases with illness onset between May 1 and July 15, 2015. We defined controls as neighbours of case without skin lesions since last 3 months. Ulcer exudates and rolled over swabs from wounds were processed in Gram stain in the Koraput district headquarter hospital laboratory. Result We identified 81 cases (89% male; median age 38 years [range 5–75 years]) including 3 deaths (case fatality rate = 4%). Among 37 cases and 74 controls, illness was significantly associated with eating meat of ill cattle (OR: 14.5, 95% CI: 1.4–85.7) and with close handling of carcasses of ill animals such as burying, skinning, or chopping (OR: 342, 95% CI: 40.5–1901.8). Among 20 wound specimens collected, seven showed spore-forming, gram positive bacilli, with bamboo stick appearance suggestive of Bacillus anthracis. Conclusion Our investigation revealed significant associations between eating and handling of ill animals and presence of anthrax-like organisms in lesions. We immediately initiated livestock vaccination in the area, educated the community on safe handling practices and recommended continued regular anthrax animal vaccinations to prevent future outbreaks. more...

Mumps, a vaccine-preventable disease, cause inflammation of salivary glands and may cause severe complications, such as encephalitis, meningitis, deafness, and orchitis/oophoritis. In India, mumps vaccine is not included in the universal immunization program and during 2009 to 2014, 72 outbreaks with greater than 1500 cases were reported. In August 2016, a suspected mumps outbreak was reported in Jaisalmer block, Rajasthan. We investigated to confirm the etiology, describe the epidemiology, and recommend prevention and control measures. We defined a case as swelling in the parotid region in a Jaisalmer block resident between 23 June 2016 and 10 September 2016. We searched for cases in health facilities and house-to-house in affected villages and hamlets. We tested blood samples of cases for mumps immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA). We found 162 cases (60% males) with a median age of 9.4 years (range: 7 month-38 years) and 65 (40%) were females. Symptoms included fever (70%) and bilateral swelling in neck (65%). None of them were vaccinated against mumps. Most (84%) cases were school-going children (3-16 years old). The overall attack rate was 2%. Village A, with two hamlets, had the highest attack rate (hamlet 1 = 13% and hamlet 2 = 12%). School A of village A, hamlet 1, which accommodated 200 children in two classrooms, had an attack rate of 55%. Of 18 blood samples from cases, 11 tested positive for mumps IgM ELISA. This was a confirmed mumps outbreak in Jaisalmer block that disproportionately affected school-going children. We recommended continued surveillance, 5-day absence from school, and vaccination. more...

The US Food Safety Modernization Act (FSMA) gives food safety regulators increased authority to require implementation of safety measures to reduce the contamination of produce. To evaluate the future impact of FSMA on food safety, a better understanding is needed regarding outbreaks attributed to the consumption of raw produce. Data reported to the US Centers for Disease Control and Prevention's Foodborne Disease Outbreak Surveillance System during 1998–2013 were analysed. During 1998–2013, there were 972 raw produce outbreaks reported resulting in 34 674 outbreak-associated illnesses, 2315 hospitalisations, and 72 deaths. Overall, the total number of foodborne outbreaks reported decreased by 38% during the study period and the number of raw produce outbreaks decreased 19% during the same period; however, the percentage of outbreaks attributed to raw produce among outbreaks with a food reported increased from 8% during 1998–2001 to 16% during 2010–2013. Raw produce outbreaks were most commonly attributed to vegetable row crops (38% of outbreaks), fruits (35%) and seeded vegetables (11%). The most common aetiologic agents identified were norovirus (54% of outbreaks), Salmonella enterica (21%) and Shiga toxin-producing Escherichia coli (10%). Food-handling errors were reported in 39% of outbreaks. The proportion of all foodborne outbreaks attributable to raw produce has been increasing. Evaluation of safety measures to address the contamination on farms, during processing and food preparation, should take into account the trends occurring before FSMA implementation. more...

OBJECTIVE: Although amphibians are known Salmonella carriers, no such outbreaks have been reported. We investigated a nationwide outbreak of human Salmonella Typhimurium infections occurring predominantly among children from 2008 to 2011. METHODS: We conducted a matched case-control study. Cases were defined as persons with Salmonella Typhimurium infection yielding an isolate indistinguishable from the outbreak strain. Controls were persons with recent infection with Salmonella strains other than the outbreak strain and matched to cases by age and geography. Environmental samples were obtained from patients’ homes; traceback investigations were conducted. RESULTS: We identified 376 cases from 44 states from January 1, 2008, to December 31, 2011; 29% (56/193) of patients were hospitalized and none died. Median patient age was 5 years (range CONCLUSIONS: ADFs were the source of this nationwide pediatric predominant outbreak. Pediatricians should routinely inquire about pet ownership and advise families about illness risks associated with animals. more...

During September to October, 2006, state and local health departments and the Centers for Disease Control and Prevention investigated a large, multistate outbreak of Escherichia coli O157:H7 infections. Case patients were interviewed regarding specific foods consumed and other possible exposures. E. coli O157:H7 strains isolated from human and food specimens were subtyped using pulsed-field gel electrophoresis and multiple-locus variable-number tandem repeat analyses (MLVA). Two hundred twenty-five cases (191 confirmed and 34 probable) were identified in 27 states; 116 (56%) case patients were hospitalized, 39 (19%) developed hemolytic uremic syndrome, and 5 (2%) died. Among 176 case patients from whom E. coli O157:H7 with the outbreak genotype (MLVA outbreak strain) was isolated and who provided details regarding spinach exposure, 161 (91%) reported fresh spinach consumption during the 10 days before illness began. Among 116 patients who provided spinach brand information, 106 (91%) consumed bagged brand A. E. coli O157:H7 strains were isolated from 13 bags of brand A spinach collected from patients' homes; isolates from 12 bags had the same MLVA pattern. Comprehensive epidemiologic and laboratory investigations associated this large multistate outbreak of E. coli O157:H7 infections with consumption of fresh bagged spinach. MLVA, as a supplement to pulsed-field gel electrophoresis genotyping of case patient isolates, was important to discern outbreak-related cases. This outbreak resulted in enhanced federal and industry guidance to improve the safety of leafy green vegetables and launched an independent collaborative approach to produce safety research in 2007. more...

SUMMARYIn November 2009, we initiated a multistate investigation of Salmonella Montevideo infections with pulsed-field gel electrophoresis pattern JIXX01.0011. We identified 272 cases in 44 states with illness onset dates ranging from 1 July 2009 to 14 April 2010. To help generate hypotheses, warehouse store membership card information was collected to identify products consumed by cases. These records identified 19 ill persons who purchased company A salami products before onset of illness. A case-control study was conducted. Ready-to-eat salami consumption was significantly associated with illness (matched odds ratio 8·5, 95% confidence interval 2·1–75·9). The outbreak strain was isolated from company A salami products from an environmental sample from one manufacturing plant, and sealed containers of black and red pepper at the facility. This outbreak illustrates the importance of using membership card information to assist in identifying suspect vehicles, the potential for spices to contaminate ready-to-eat products, and preventing raw ingredient contamination of these products. more...

Background Salmonella enterica serovar Typhi (Salmonella Typhi) causes an estimated 22 million typhoid fever cases and 216 000 deaths annually worldwide. In Africa, the lack of laboratory diagnostic capacity limits the ability to recognize endemic typhoid fever and to detect outbreaks. We report a large laboratory-confirmed outbreak of typhoid fever in Uganda with a high proportion of intestinal perforations (IPs). Methods A suspected case of typhoid fever was defined as fever and abdominal pain in a person with either vomiting, diarrhea, constipation, headache, weakness, arthralgia, poor response to antimalarial medications, or IP. From March 4, 2009 to April 17, 2009, specimens for blood and stool cultures and serology were collected from suspected cases. Antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) were performed on Salmonella Typhi isolates. Surgical specimens from patients with IP were examined. A community survey was conducted to characterize the extent of the outbreak. Results From December 27, 2007 to July 30, 2009, 577 cases, 289 hospitalizations, 249 IPs, and 47 deaths from typhoid fever occurred; Salmonella Typhi was isolated from 27 (33%) of 81 patients. Isolates demonstrated multiple PFGE patterns and uniform susceptibility to ciprofloxacin. Surgical specimens from 30 patients were consistent with typhoid fever. Estimated typhoid fever incidence in the community survey was 8092 cases per 100 000 persons. Conclusions This typhoid fever outbreak was detected because of an elevated number of IPs. Underreporting of milder illnesses and delayed and inadequate antimicrobial treatment contributed to the high perforation rate. Enhancing laboratory capacity for detection is critical to improving typhoid fever control. more...

Raw produce is an increasingly recognized vehicle for salmonellosis. We investigated a nationwide outbreak that occurred in the United States in 2008.We defined a case as diarrhea in a person with laboratory-confirmed infection with the outbreak strain of Salmonella enterica serotype Saintpaul. Epidemiologic, traceback, and environmental studies were conducted.Among the 1500 case subjects, 21% were hospitalized, and 2 died. In three case-control studies of cases not linked to restaurant clusters, illness was significantly associated with eating raw tomatoes (matched odds ratio, 5.6; 95% confidence interval [CI], 1.6 to 30.3); eating at a Mexican-style restaurant (matched odds ratio, 4.6; 95% CI, 2.1 to ∞) and eating pico de gallo salsa (matched odds ratio, 4.0; 95% CI, 1.5 to 17.8), corn tortillas (matched odds ratio, 2.3; 95% CI, 1.2 to 5.0), or salsa (matched odds ratio, 2.1; 95% CI, 1.1 to 3.9); and having a raw jalapeño pepper in the household (matched odds ratio, 2.9; 95% CI, 1.2 to 7.6). In nine analyses of clusters associated with restaurants or events, jalapeño peppers were implicated in all three clusters with implicated ingredients, and jalapeño or serrano peppers were an ingredient in an implicated item in the other three clusters. Raw tomatoes were an ingredient in an implicated item in three clusters. The outbreak strain was identified in jalapeño peppers collected in Texas and in agricultural water and serrano peppers on a Mexican farm. Tomato tracebacks did not converge on a source.Although an epidemiologic association with raw tomatoes was identified early in this investigation, subsequent epidemiologic and microbiologic evidence implicated jalapeño and serrano peppers. This outbreak highlights the importance of preventing raw-produce contamination. more...

We report shedding duration of 2009 pandemic influenza A (pH1N1) virus from a school-associated outbreak in Pennsylvania during May through June 2009. Outbreak-associated students or household contacts with influenza-like illness (ILI) onset within 7 days of interview were recruited. Nasopharyngeal specimens, collected every 48 hours until 2 consecutive nonpositive tests, underwent real-time reverse transcriptase polymerase chain reaction (rRT-PCR) and culture for pH1N1 virus. Culture-positive specimens underwent virus titrations. Twenty-six (median age, 8 years) rRT-PCR-positive persons, for pH1N1 virus, were included in analysis. Median shedding duration from fever onset by rRT-PCR was 6 days (range, 1-13) and 5 days (range, 1-7) by culture. Following fever resolution virus was isolated for a median of 2 days (range, 0-5). Highest and lowest virus titers detected, 2 and 5 days following fever onset, were 3.2 and 1.2 log(10) TCID(50)/mL respectively. Overall, shedding duration in children and adults were similar to seasonal influenza viruses. more...

Evaluating the impact of different social networks on the spread of respiratory diseases has been limited by a lack of detailed data on transmission outside the household setting as well as appropriate statistical methods. Here, from data collected during a H1N1 pandemic (pdm) influenza outbreak that started in an elementary school and spread in a semirural community in Pennsylvania, we quantify how transmission of influenza is affected by social networks. We set up a transmission model for which parameters are estimated from the data via Markov chain Monte Carlo sampling. Sitting next to a case or being the playmate of a case did not significantly increase the risk of infection; but the structuring of the school into classes and grades strongly affected spread. There was evidence that boys were more likely to transmit influenza to other boys than to girls (and vice versa), which mimicked the observed assortative mixing among playmates. We also investigated the presence of abnormally high transmission occurring on specific days of the outbreak. Late closure of the school (i.e., when 27% of students already had symptoms) had no significant impact on spread. School-aged individuals (6–18 y) facilitated the introduction and spread of influenza in households, but only about one in five cases aged >18 y was infected by a school-aged household member. This analysis shows the extent to which clearly defined social networks affect influenza transmission, revealing strong between-place interactions with back-and-forth waves of transmission between the school, the community, and the household. more...

Much research into food-borne human pathogens has focused on transmission from foods of animal origin. However, recent investigations have identified fruits and vegetables are the source of many disease outbreaks. Now believed to be a much larger contributor to produce-associated outbreaks than previously reported, norovirus outbreaks are commonly caused by contamination of foods from hands of infected workers. Although infections with Shiga toxin-producing E. coli O157 have been linked to beef more often than to any other food product, severe outbreaks have been traced to consumption of contaminated radish sprouts and pre-packaged spinach. Similarly, while infections with Salmonella have mainly been linked to consumption of foods of animal origin, many outbreaks have been traced to contaminated fresh produce. E. coli O157 binds to lettuce leaves by alternative mechanisms involving the filamentous type III secretions system, flagella and the pilus curli. Association of Salmonella with fresh produce appears to be serovar-specific involving flagella, curli, cellulose, and O antigen capsule. A better understanding of plant, microbiological, environmental, processing and food handling factors that facilitate contamination will allow development of evidence-based policies, procedures and technologies aimed at reducing the risk of contamination of fresh produce. more...

Indigenous wild poliovirus has been eliminated in 98% of endemic countries since 1988, with a decrease from 350 000 cases in 1988 to 223 confirmed cases in 2012 [1]. The success of polio eradication efforts has been dependent on increasing population immunity through routine immunization and supplementary immunization activities and by improving surveillance for acute flaccid paralysis (AFP). AFP surveillance systems are expected to annually identify ≥2 nonpolio AFP (NPAFP) cases per 100 000 population under 15 years of age to demonstrate that their systems are sensitive enough to detect paralytic polio cases [2]. All countries within the Horn of Africa region have successfully eliminated endemic poliovirus circulation, with Kenya successfully presenting in 2005 their complete country documentation outlining polio-free status. However, the region has remained at high risk for reintroduction and has had multiple outbreaks in recent years. An outbreak of 19 cases of wild poliovirus occurred in Turkana, Kenya, in 2009, and was followed by an outbreak of 22 cases in Uganda in 2010. In 2011, another wild poliovirus case was detected in western Kenya and was found to be genetically related to the 2010 outbreak in Uganda. These outbreaks indicated missed circulation within the region over a 3-year period. As of 31 December, 203 confirmed cases of WPV had been confirmed in the Horn of Africa in 2013. All of these outbreaks underscore the regional struggle to achieve the surveillance sensitivity and population immunity necessary to prevent transmission of imported poliovirus. In the midst of these outbreaks, the health system in Kenya has been decentralized, with both increased administrative autonomy at the district level and an increase in number of districts. Following a risk analysis performed in January 2012, which showed that 121 of 159 (77%) of districts in Kenya were at high or medium risk for a polio outbreak, the Kenya Ministry of Public Health and Sanitation (MoPHS) engaged the US Centers for Disease Control and Prevention (CDC), World Health Organization (WHO), United Nations Children’s Fund (UNICEF), and other international partners to assist in a review of the national surveillance and routine immunization systems. The purpose of the review was to identify gaps in the programs, as well as to provide recommendations toward improving detection of imported poliovirus and preventing poliovirus circulation during this period of health system decentralization [3]. more...

In May 2009, one of the earliest outbreaks of 2009 pandemic influenza A virus (pH1N1) infection resulted in the closure of a semi-rural Pennsylvania elementary school. Two sequential telephone surveys were administered to 1345 students (85% of the students enrolled in the school) and household members in 313 households to collect data on influenza-like illness (ILI). A total of 167 persons (12.4%) among those in the surveyed households, including 93 (24.0%) of the School A students, reported ILI. Students were 3.1 times more likely than were other household members to develop ILI (95% confidence interval [CI], 2.3-4.1). Fourth-grade students were more likely to be affected than were students in other grades (relative risk, 2.2; 95% CI, 1.2-3.9). pH1N1 was confirmed in 26 (72.2%) of the individuals tested by real-time reverse-transcriptase polymerase chain reaction. The outbreak did not resume upon the reopening of the school after the 7-day closure. This investigation found that pH1N1 outbreaks at schools can have substantial attack rates; however, grades and classrooms are affected variably. Additional study is warranted to determine the effectiveness of school closure during outbreaks. more...

BACKGROUND: In May 2008, PulseNet detected a multistate outbreak of Salmonella enterica serotype Saintpaul infections. Initial investigations identified an epidemiologic association between illness and consumption of raw tomatoes, yet cases continued. In mid-June, we investigated two clusters of outbreak strain infections in Texas among patrons of Restaurant A and two establishments of Restaurant Chain B to determine the outbreak's source. METHODOLOGY/PRINCIPAL FINDINGS: We conducted independent case-control studies of Restaurant A and B patrons. Patients were matched to well controls by meal date. We conducted restaurant environmental investigations and traced the origin of implicated products. Forty-seven case-patients and 40 controls were enrolled in the Restaurant A study. Thirty case-patients and 31 controls were enrolled in the Restaurant Chain B study. In both studies, illness was independently associated with only one menu item, fresh salsa (Restaurant A: matched odds ratio [mOR], 37; 95% confidence interval [CI], 7.2-386; Restaurant B: mOR, 13; 95% CI 1.3-infinity). The only ingredient in common between the two salsas was raw jalapeño peppers. Cultures of jalapeño peppers collected from an importer that supplied Restaurant Chain B and serrano peppers and irrigation water from a Mexican farm that supplied that importer with jalapeño and serrano peppers grew the outbreak strain. CONCLUSIONS/SIGNIFICANCE: Jalapeño peppers, contaminated before arrival at the restaurants and served in uncooked fresh salsas, were the source of these infections. Our investigations, critical in understanding the broader multistate outbreak, exemplify an effective approach to investigating large foodborne outbreaks. Additional measures are needed to reduce produce contamination. more...

SUMMARYA multistate outbreak ofEscherichia coliO157:H7 infections occurred in the USA in November–December 2006 in patrons of restaurant chain A. We identified 77 cases with chain A exposure in four states – Delaware, New Jersey, New York, and Pennsylvania. Fifty-one (66%) patients were hospitalized, and seven (9%) developed haemolytic uraemic syndrome; none died. In a matched analysis controlling for age in 31 cases and 55 controls, illness was associated with consumption of shredded iceberg lettuce [matched odds ratio (mOR) 8·0, 95% confidence interval (CI) 1·1–348·1] and shredded cheddar cheese (mOR 6·2, CI 1·7–33·7). Lettuce, an uncooked ingredient, was more commonly consumed (97% of patients) than cheddar cheese (84%) and a single source supplied all affected restaurants. A single source of cheese could not explain the regional distribution of outbreak cases. The outbreak highlights challenges in conducting rapid multistate investigations and the importance of incorporating epidemiological study results with other investigative findings. more...