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Immunity gaps caused by COVID-19-related disruptions highlight the importance of catch-up vaccination. Number of countries offering vaccines in second year of life (2YL) has increased, but use of 2YL for catch-up vaccination has been variable. We assessed pre-pandemic use of 2YL for catch-up vaccination in three countries (Pakistan, the Philippines, and South Africa), based on existence of a 2YL platform (demonstrated by offering second dose of measles-containing vaccine (MCV2) in 2YL), proportion of card availability, and geographical variety.We conducted a secondary data analysis of immunization data from Demographic and Health Surveys (DHS) in Pakistan (2017-2018), the Philippines (2017), and South Africa (2016). We conducted time-to-event analyses for pentavalent vaccine (diphtheria-tetanus-pertussis-Hepatitis B-Haemophilus influenzae type b [Hib]) and MCV and calculated use of 2YL and MCV visits for catch-up vaccination.Among 24-35-month-olds with documented dates, coverage of third dose of pentavalent vaccine increased in 2YL by 2%, 3%, and 1% in Pakistan, Philippines, and South Africa, respectively. MCV1 coverage increased in 2YL by 5% in Pakistan, 10% in the Philippines, and 3% in South Africa. In Pakistan, among 124 children eligible for catch-up vaccination of pentavalent vaccine at time of a documented MCV visit, 45% received a catch-up dose. In the Philippines, among 381 eligible children, 38% received a pentavalent dose during an MCV visit. In South Africa, 50 children were eligible for a pentavalent vaccine dose before their MCV1 visit, but only 20% received it; none with MCV2.Small to modest vaccine coverage improvements occurred in all three countries through catch-up vaccination in 2YL but many missed opportunities for vaccination continue to occur. Using the 2YL platform can increase coverage and close immunity gaps, but immunization programmes need to change policies, practices, and monitor catch-up vaccination to maximize the potential. more...

To analyse subnational inequality in diphtheria-tetanus-pertussis (DTP) immunization dropout in 24 African countries using administrative data on receipt of the first and third vaccine doses (DTP1 and DTP3, respectively) collected by the Joint Reporting Process of the World Health Organization and the United Nations Children's Fund.Districts in each country were grouped into quintiles according to the proportion of children who dropped out between DTP1 and DTP3 (i.e. the dropout rate). We used six summary measures to quantify inequalities in dropout rates between districts and compared rates with national dropout rates and DTP1 and DTP3 immunization coverage.The median dropout rate across countries was 2.4% in quintiles with the lowest rate and 14.6% in quintiles with the highest rate. In eight countries, the difference between the highest and lowest quintiles was 14.9 percentage points or more. In most countries, underperforming districts in the quintile with the highest rate tended to lag disproportionately behind the others. This divergence was not evident from looking only at national dropout rates. Countries with the largest inequalities in absolute subnational dropout rate tended to have lower estimated national DTP1 and DTP3 immunization coverage.There were marked inequalities in DTP immunization dropout rates between districts in most countries studied. Monitoring dropout at the subnational level could help guide immunization interventions that address inequalities in underserved areas, thereby improving overall DTP3 coverage. The quality of administrative data should be improved to ensure accurate and timely assessment of geographical inequalities in immunization.Analyser les inégalités régionales en matière de taux d'abandon du vaccin diphtérique-tétanique-coquelucheux (DTC) dans 24 pays de la région Afrique, en se fondant sur les données administratives relatives à l'injection de la première et de la troisième dose du vaccin (DTC1 et DTC3, respectivement) collectées dans le cadre du Rapport conjoint de notification de l'Organisation mondiale de la Santé et du Fonds des Nations Unies pour l'enfance.Dans chaque pays, les districts ont été regroupés en quintiles selon le pourcentage d'enfants ayant interrompu la vaccination entre DTC1 et DTC3 (taux d'abandon). Nous avons employé six mesures synthétiques afin de quantifier les inégalités en matière de taux d'abandon entre districts, puis nous avons comparé ces taux avec les taux d'abandon nationaux ainsi qu’avec la couverture vaccinale DTC1 et DTC3.Le taux d'abandon médian dans les différents pays s'élevait à 2,4% dans les quintiles affichant le taux le plus bas, et atteignait 14,6% dans les quintiles affichant le taux le plus haut. Dans huit pays, l'écart entre le quintile le plus haut et le quintile le plus bas était égal ou supérieur à 14,9 points de pourcentage. Dans la plupart des pays, les districts enregistrant les moins bonnes performances dans le quintile avec le taux le plus élevé étaient plus enclins à se laisser exagérément distancer par les autres. Une divergence qui passait inaperçue lorsqu'on ne tenait compte que des taux d'abandon nationaux. Les pays confrontés aux plus importantes inégalités en termes de taux d'abandon régional absolu étaient plus enclins, selon les estimations, à présenter une couverture vaccinale DTC1 et DTC3 moins élevée à l'échelle nationale.Dans la plupart des pays étudiés, nous avons constaté de fortes disparités entre districts concernant les taux d'abandon du vaccin DTC. Assurer un contrôle sur ces taux d'abandon au niveau régional pourrait orienter les campagnes de vaccination visant à réduire les inégalités dans les zones mal desservies, ce qui offrirait une meilleure couverture DTC3 globale. Enfin, la qualité des données administratives devrait être améliorée afin de fournir des évaluations précises et ponctuelles des variations géographiques en matière de vaccination.Analizar la desigualdad subnacional en el abandono de la inmunización contra la difteria, el tétanos y la tos ferina (DTP) en 24 países africanos utilizando datos administrativos sobre la recepción de la primera y la tercera dosis de la vacuna (DTP1 y DTP3, respectivamente) recogidos por el proceso de informes conjuntos de la Organización Mundial de la Salud y el Fondo de las Naciones Unidas para la Infancia.Los distritos de cada país se agruparon en quintiles según la proporción de niños que abandonaron la vacunación entre la DTP1 y la DTP3 (es decir, la tasa de abandono). Se utilizaron seis medidas de resumen para cuantificar las desigualdades en las tasas de abandono entre los distritos y se compararon estas tasas con las tasas nacionales de abandono y la cobertura de inmunización DTP1 y DTP3.La mediana de la tasa de abandono de la vacunación en todos los países fue del 2,4 % en los quintiles con la tasa más baja y del 14,6 % en los quintiles con la tasa más alta. En ocho países, la diferencia entre los quintiles más altos y más bajos era de 14,9 puntos porcentuales o más. En la mayoría de los países, los distritos con peores resultados en el quintil con la tasa más alta tendían a estar desproporcionadamente por detrás de los demás. Esta divergencia no era evidente si se observaban únicamente las tasas nacionales de abandono de la vacunación. Los países con las mayores desigualdades en la tasa absoluta de abandono de la vacunación subnacional tendían a tener una cobertura nacional estimada de inmunización DTP1 y DTP3 más baja.En la mayoría de los países estudiados hubo desigualdades claras en las tasas de abandono de la vacunación DTP entre los distritos. El seguimiento del abandono a nivel subnacional podría ayudar a orientar las intervenciones de inmunización que abordan las desigualdades en las zonas desatendidas, mejorando así la cobertura general de DTP3. La calidad de los datos administrativos debe mejorarse para garantizar una evaluación precisa y oportuna de las desigualdades geográficas en la inmunización.لتحليل حالة التفاوت دون الوطنية في التسرب من التحصين ضد الدفتيريا والتيتانوس والسعال الديكي (DTP) في 24 دولة أفريقية باستخدام البيانات الإدارية عند تلقي جرعتي التحصين الأولى والثالثة (DTP1 وDTP3 على التوالي)، والتي تم جمعها بواسطة عملية الإبلاغ المشتركة لمنظمة الصحة العالمية، ومنظمة الأمم المتحدة للطفولة.تم تجميع المناطق في كل دولة في مجموعات خمسية وفقًا لنسبة الأطفال الذين تسربوا بين الجرعتين DTP1 وDTP3 (أي معدل التسرب). استخدمنا ستة مقاييس موجزة لقياس حالات التفاوت في معدلات التسرب بين المناطق، وقمنا بمقارنة هذه المعدلات مع معدلات التسرب الوطنية وتغطية التحصين ضد الجرعتين DTP1 وDTP3.كان متوسط معدل التسرب عبر الدول 2.4% في المجموعات الخمسية ذات المعدل الأقل، و14.6% في المجموعات الخمسية ذات المعدل الأعلى. في ثماني دول، كان الفرق بين أعلى وأقل شريحتين 14.9 نقطة مئوية أو أكثر. في معظم الدول، كانت المناطق ذات الأداء الضعيف في المجموعة الخمسية ذات أعلى معدل، تميل إلى التدهور بشكل غير متناسب عن غيرها من المناطق. لم يكن هذا الاختلاف واضحًا من مجرد النظر فقط إلى معدلات التسرب الوطنية. تميل الدول التي لديها أكبر تفاوتات في معدل التسرب المطلق دون الوطني، إلى أن يكون لديها تغطية تحصين وطنية تقديرية أقل من الجرعتين DTP1 وDTP3.كانت هناك تفاوتات ملحوظة في معدلات التسرب من التحصين ضد الدفتيريا والتيتانوس والسعال الديكي بين المناطق في معظم الدول التي شملتها الدراسة. يمكن لمراقبة التسرب على المستوى دون الوطني أن تساعد في توجيه تدخلات التحصين التي تعالج التفاوتات في المناطق المحرومة، وبالتالي تحسين التغطية الشاملة للجرعة DTP3. يجب تحسين جودة البيانات الإدارية لضمان التقييم الدقيق وفي الوقت المناسب للتفاوتات في التحصين.使用世界卫生组织和联合国儿童基金会联合报告中收集的有关接种第一剂和第三剂疫苗（分别为 DTP1 和 DTP3）的管理数据，分析24个非洲国家关于白喉-破伤风-百日咳 (DTP) 免疫接种的地区不均问题。.根据要接种 DTP1 和 DTP3 却未完成全部接种的儿童比例（即辍接种率），将每个国家的地区按五分位置划分。我们使用六种综合测量方法来量化地区之间辍接种率的不均衡，并将其与国家辍接种率以及 DTP1 和 DTP3 免疫覆盖率进行比较。.各国的辍接种率中位数最低的五分之一为 2.4%，最高的五分之一为 14.6%。在八个国家中，最高和最低五分之一之间的差距为 14.9 个百分点或更多。在大多数国家，辍接种率最高的五分之一中，表现不佳的地区，远远落后于其他地区。仅从国家间的辍接种率来看，这种差异并不明显。地区辍接种率不均衡程度最大的国家，往往具有较低的预计国家 DTP1 和 DTP3 免疫覆盖率。.在大多数受调查的国家中，各地区之间 DTP 辍接种率存在明显不均。监测地区辍接种率，有助于对服务欠缺地区的不均衡问题进行免疫干预指导，从而提高 DTP3 的整体覆盖率。应提高管理数据的质量，以确保准确、及时地评估免疫接种方面的地域不均问题。.По коэффициентам выбытия проанализировать неравенство на субнациональном уровне в области охвата иммунизацией коклюшно-дифтерийно-столбнячной вакциной (КДС) в 24 африканских странах с использованием административных данных о получении первой и третьей доз вакцины (КДС-1 и КДС-3 соответственно), собранных в рамках Единого процесса отчетности Всемирной организации здравоохранения и Детского фонда Организации Объединенных Наций.Районы в каждой стране были сгруппированы по квинтилям согласно доле детей, выбывших между получением доз КДС-1 и КДС-3 (т. е. коэффициент выбытия). Мы использовали шесть сводных показателей для количественной оценки неравенства по коэффициентам выбытия между районами и сравнили коэффициенты с национальными коэффициентами выбытия и охватом иммунизацией КДС-1 и КДС-3.Для всех стран в квинтилях с наиболее низкими коэффициентами выбытия медианное значение выбытия составило 2,4%, в квинтилях с наиболее высокими коэффициентами выбытия — 14,6%. В восьми странах разница в показателях между квинтилями с наиболее высокими и наиболее низкими коэффициентами выбытия составила 14,9 процентного пункта или больше.. В большинстве стран отстающие районы в квинтилях с наиболее высокими коэффициентами выбытия имели тенденцию к непропорциональному отставанию по сравнению с другими районами. Это расхождение не было очевидным, если ориентироваться только на национальные коэффициенты выбытия. Страны с самым высоким уровнем неравенства по абсолютным коэффициентам выбытия на субнациональном уровне, как правило, имели более низкий оценочный уровень национального охвата иммунизацией КДС-1 и КДС-3.В большинстве изученных стран наблюдалось неравенство между районами в коэффициентах выбытия в период получения КДС-вакцины. Мониторинг выбытия на субнациональном уровне может помочь в проведении мероприятий по иммунизации, направленных на устранение неравенства в недостаточно обслуживаемых районах, тем самым улучшая общий охват иммунизацией КДС-3. Качество административных данных должно быть улучшено для обеспечения точной и своевременной оценки географического неравенства в области охвата иммунизацией. 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...

Introduction Immunization programs in developing countries increasingly face challenges to ensure equitable delivery of services within cities where rapid urban growth can result in informal settlements, poor living conditions, and heterogeneous populations. A number of strategies have been utilized in developing countries to ensure high community demand and equitable availability of urban immunization services; however, a synthesis of the literature on these strategies has not previously been undertaken. Methods We reviewed articles published in English in peer-reviewed journals between 1990 and 2013 that assessed interventions for improving routine immunization coverage in urban areas in low- and middle-income countries. We categorized the intervention in each study into one of three groups: (1) interventions aiming to increase utilization of immunization services; (2) interventions aiming to improve availability of immunization services by healthcare providers, or (3) combined availability and utilization interventions. We summarized the main quantitative outcomes from each study and effective practices from each intervention category. Results Fifteen studies were identified; 87% from the African, Eastern Mediterranean and Southeast Asian regions of the World Health Organization (WHO). Six studies were randomized controlled trials, eight were pre- and post-intervention evaluations, and one was a cross-sectional study. Four described interventions designed to improve availability of routine immunization services, six studies described interventions that aimed to increase utilization, and five studies aiming to improve both availability and utilization of services. All studies reported positive change in their primary outcome indicator, although seven different primary outcomes indicators were used across studies. Studies varied considerably with respect to the type of intervention assessed, study design, and length of intervention assessment. Conclusion Few studies have assessed interventions designed explicitly for the unique challenges facing immunization programs in urban areas. Further research on sustainability, scalability, and cost-effectiveness of interventions is needed to fill this gap. 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...

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...

To determine the effects of school closure, we surveyed 214 households after a 1-week elementary school closure because of pandemic (H1N1) 2009. Students spent 77% of the closure days at home, 69% of students visited at least 1 other location, and 79% of households reported that adults missed no days of work to watch children. more...

In Indonesia, where diarrhea remains a major cause of mortality among children

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...

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...