Convergence of Humans, Bats, Trees, and Culture in Nipah Virus Transmission, Bangladesh.

Preventing emergence of new zoonotic viruses depends on understanding determinants for human risk. Nipah virus (NiV) is a lethal zoonotic pathogen that has spilled over from bats into human populations, with limited person-to-person transmission. We examined ecologic and human behavioral drivers of geographic variation for risk of NiV infection in Bangladesh. We visited 60 villages during 2011-2013 where cases of infection with NiV were identified and 147 control villages. We compared case villages with control villages for most likely drivers for risk of infection, including number of bats, persons, and date palm sap trees, and human date palm sap consumption behavior. Case villages were similar to control villages in many ways, including number of bats, persons, and date palm sap trees, but had a higher proportion of households in which someone drank sap. Reducing human consumption of sap could reduce virus transmission and risk for emergence of a more highly transmissible NiV strain.

Hand contamination with human rhinovirus in Bangladesh.

As one step in developing a measure of hand contamination with respiratory viruses, this study assessed if human rhinovirus (HRV) was detectable on hands in a low income non-temperate community where respiratory disease is a leading cause of child death. Research assistants observed residents in a low income community in Dhaka, Bangladesh. When they observed a resident sneeze or pick their nose, they collected a hand rinse and anterior nare sample from the resident. Samples were first tested for HRV RNA by real-time RT-PCR (rRT-PCR). A subset of rRT-PCR positive samples were cultured into MRC-5 and HeLa Ohio cells. Among 177 hand samples tested for HRV by real-time RT-PCR, 52 (29%) were positive. Among 15 RT-PCR positive hand samples that were cultured, two grew HRV. HRV was detected in each of the sampling months (January, February, June, July, November, and December). This study demonstrates in the natural setting that, at least after sneezing or nasal cleaning, hands were contaminated commonly with potentially infectious HRV. Future research could explore if HRV RNA is present consistently and is associated sufficiently with the incidence of respiratory illness in communities that it may provide a proxy measure of respiratory viral hand contamination.

Impact of introduction of the Haemophilus influenzae type b conjugate vaccine into childhood immunization on meningitis in Bangladeshi infants.

OBJECTIVES: Some Asian countries have been reluctant to adopt Haemophilus influenzae type b (Hib) conjugate vaccination because of uncertainty over disease burden. We assessed the impact of introduction of Hib conjugate vaccine into the Expanded Program on Immunization in Bangladesh on purulent and laboratory-confirmed H influenzae meningitis. STUDY DESIGN: Within a well-defined catchment area around 2 surveillance hospitals in Dhaka, Bangladesh, we compared the incidence of Hib meningitis confirmed by culture, latex agglutination, and polymerase chain reaction assay among infants 1 year before and 1 year after introduction of Hib conjugate vaccine. We adjusted the incidence rate for the proportion of children who sought care at the surveillance hospitals. RESULTS: Among infants, the incidence of confirmed Hib meningitis decreased from 92-16 cases per 100,000 within 1 year of vaccine introduction (vaccine preventable incidence = 76; 95% CI 18, 135 per 100,000). The incidence of purulent meningitis decreased from 1659-1159 per 100,000 (vaccine preventable incidence = 500; 95% CI: 203, 799 per 100,000). During the same time period, there was no significant difference in the incidence of meningitis due to Streptococcus pneumoniae. CONCLUSIONS: Introduction of conjugate Hib conjugate vaccine into Bangladesh Expanded Program on Immunization markedly reduced the burden of Hib and purulent meningitis.

Seasonality, timing, and climate drivers of influenza activity worldwide.

BACKGROUND: Although influenza is a vaccine-preventable disease that annually causes substantial disease burden, data on virus activity in tropical countries are limited. We analyzed publicly available influenza data to better understand the global circulation of influenza viruses. METHOD: We reviewed open-source, laboratory-confirmed influenza surveillance data. For each country, we abstracted data on the percentage of samples testing positive for influenza each epidemiologic week from the annual number of samples testing positive for influenza. The start of influenza season was defined as the first week when the proportion of samples that tested positive remained above the annual mean. We assessed the relationship between percentage of samples testing positive and mean monthly temperature with use of regression models. FINDINGS: We identified data on laboratory-confirmed influenza virus infection from 85 countries. More than one influenza epidemic period per year was more common in tropical countries (41%) than in temperate countries (15%). Year-round activity (ie, influenza virus identified each week having ≥ 10 specimens submitted) occurred in 3 (7%) of 43 temperate, 1 (17%) of 6 subtropical, and 11 (37%) of 30 tropical countries with available data (P = .006). Percentage positivity was associated with low temperature (P = .001). INTERPRETATION: Annual influenza epidemics occur in consistent temporal patterns depending on climate.

Incidence of influenza-like illness and severe acute respiratory infection during three influenza seasons in Bangladesh, 2008-2010.

OBJECTIVE: To determine how much influenza contributes to severe acute respiratory illness (SARI), a leading cause of death in children, among people of all ages in Bangladesh. METHODS: Physicians obtained nasal and throat swabs to test for influenza virus from patients who were hospitalized within 7 days of the onset of severe acute respiratory infection (SARI) or who consulted as outpatients for influenza-like illness (ILI). A community health care utilization survey was conducted to determine the proportion of hospital catchment area residents who sought care at study hospitals and calculate the incidence of influenza using this denominator. FINDINGS: The estimated incidence of SARI associated with influenza in children < 5 years old was 6.7 (95% confidence interval, CI: 0-18.3); 4.4 (95% CI: 0-13.4) and 6.5 per 1000 person-years (95% CI: 0-8.3/1000) during the 2008, 2009 and 2010 influenza seasons, respectively. The incidence of SARI in people aged ≥ 5 years was 1.1 (95% CI: 0.4-2.0) and 1.3 (95% CI: 0.5-2.2) per 10,000 person-years during 2009 and 2010, respectively. The incidence of medically attended, laboratory-confirmed seasonal influenza in outpatients with ILI was 10 (95% CI: 8-14), 6.6 (95% CI: 5-9) and 17 per 100 person-years (95% CI: 13-22) during the 2008, 2009 and 2010 influenza seasons, respectively. CONCLUSION: Influenza-like illness is a frequent cause of consultation in the outpatient setting in Bangladesh. Children aged less than 5 years are hospitalized for influenza in greater proportions than children in other age groups.

Resumen OBJETIVO: Determinar en qué medida contribuye la gripe a la enfermedad respiratoria aguda grave (ERAG), una de las principales causas de muerte infantil, en personas de todas las edades en Bangladesh. MÉTODOS: Los médicos tomaron muestras de exudado nasal y faríngeo para realizar la prueba del virus de la gripe en pacientes que estuvieron hospitalizados en los 7 días posteriores al inicio de la infección respiratoria agua grave (IRAG) o que acudieron a consulta como pacientes ambulatorios por síndrome gripal (SG). Se llevó a cabo un estudio sobre el uso de la asistencia sanitaria comunitaria para determinar la proporción de residentes del área de cobertura del hospital que solicitaron asistencia médica en hospitales pertenecientes al estudio y se calculó la incidencia de la gripe con este denominador. RESULTADOS: La incidencia estimada de la IRAG asociada con la gripe en niños menores de 5 años fue del 6,7 (95% de intervalo de confianza, IC: 0-18,3); 4,4 (95% IC: 0-13,4) y 6,5 por 1000 años-persona (95% IC: 0-8,3/1000) durante las temporadas de gripe de 2008, 2009 y 2010, respectivamente. La incidencia de la IRAG en las personas con una edad igual o superior a 5 años fue del 1,1 (95% IC: 0,4- 2,0) y 1,3 (95% IC: 0,5-2,2) por 10 000 años-persona durante 2009 y 2010, respectivamente. La incidencia de la gripe de temporada tratada médicamente y confirmada en laboratorio en pacientes ambulatorios con SG fue de 10 (95% IC: 8-14); 6,6 (95% IC: 5-9) y 17 por 100 años-persona (95% IC: 13-22/1000) durante las temporadas de gripe de 2008, 2009 y 2010, respectivamente. CONCLUSIÓN: El síndrome gripal es una causa frecuente de consulta en los centros ambulatorios en Bangladesh. La proporción de niños menores de 5 años hospitalizados por gripe es mayor que la de niños en otros grupos de edad.

Résumé OBJECTIF: Déterminer l'impact de la grippe sur le syndrome respiratoire aigu sévère (SRAS), une cause majeure de la mortalité chez les enfants, chez les personnes de tous les âges au Bangladesh. MÉTHODES: Les médecins ont obtenu des écouvillons de prélèvement de nez et de gorge afin de tester le virus de la grippe chez des patients qui avaient été hospitalisés dans les 7 jours suivants l'apparition de l'infection respiratoire aiguë sévère (SRAS) ou qui avaient eu une consultation déambulatoire pour un syndrome de type grippal (STG). Une enquête sur l'utilisation des soins de santé communautaires a été effectuée afin de définir la proportion des riverains de la circonscription hospitalière, qui avaient reçu des soins dans les hôpitaux universitaires, et afin de calculer l'incidence de la grippe à l'aide de ce dénominateur. RÉSULTATS: L'estimation de l'incidence du SRAS associé à la grippe chez les enfants de moins de 5 ans était de 6,7 (intervalle de confiance de 95%, IC: 0-18.3); de 4,4 (IC de 95%: 0-13.4) et de 6,5 pour 1 000 personnes-années (IC de 95%: 0-8.3/1000) lors des saisons de la grippe de 2008, 2009 et 2010, respectivement. L'incidence du SRAS chez les personnes âgées de plus de 5 ans était de 1,1 (IC de 95%: 0.4-2.0) et 1,3 (IC de 95%: 0.5-2.2) pour 10 000 personnes-années en 2009 et 2010, respectivement. L'incidence de la grippe saisonnière traitée médicalement et confirmée en laboratoire chez les patients en consultation ambulatoire souffrant du STG était de 10 (IC de 95%: 8-14), 6,6 (IC de 95%: 5-9) et de 17 pour 100 personnes-années (IC de 95%: 13-22) lors des saisons de la grippe de 2008, 2009 et 2010, respectivement. CONCLUSION: Le syndrome de type grippal est une cause fréquente de consultation dans la configuration de la consultation ambulatoire au Bangladesh. Les enfants de moins de 5 ans sont hospitalisés pour la grippe dans des proportions supérieures aux enfants des autres groupes d'âge.

Poultry slaughtering practices in rural communities of Bangladesh and risk of avian influenza transmission: a qualitative study.

Slaughtering sick poultry is a risk factor for human infection with highly pathogenic avian influenza and is a common practice in Bangladesh. This paper describes human exposures to poultry during slaughtering process and the customs and rituals influencing these practices in two Bangladeshi rural communities. In 2009, we conducted 30 observations to observe slaughtering practices and 110 in-depth and short interviews and 36 group discussions to explore reasons behind those practices. The villagers reported slaughtering 103 poultry, including 20 sick poultry during 2 months. During different stages of slaughtering, humans, the environment, healthy poultry, and other animals were exposed to poultry blood and body parts. Women performed most of the slaughtering tasks, including evisceration. Defeathering required the most time and involved several persons. During festivals, ceremonies, and rituals, many people gathered and participated in the slaughtering of poultry. Exposure to poultry slaughtering created numerous opportunities for potential avian influenza transmission. Strategies that can be further tested to determine if they reduce the risk of transmission include skinning the carcasses of sick poultry, using hot water for defeathering and cleaning, using a bucket to contain slaughtering blood and carcass, burying the offal and encouraging handwashing.

Incidence of and risk factors for hospital-acquired diarrhea in three tertiary care public hospitals in Bangladesh.

During April 2007-April 2010, surveillance physicians in adult and pediatric medicine wards of three tertiary public hospitals in Bangladesh identified patients who developed hospital-acquired diarrhea. We calculated incidence of hospital-acquired diarrhea. To identify risk factors, we compared these patients to randomly selected patients from the same wards who were admitted > 72 hours without having diarrhea. The incidence of hospital-acquired diarrhea was 4.8 cases per 1,000 patient-days. Children < 1 year of age were more likely to develop hospital-acquired diarrhea than older children. The risk of developing hospital-acquired diarrhea increased for each additional day of hospitalization beyond 72 hours, whereas exposure to antibiotics within 72 hours of admission decreased the risk. There were three deaths among case-patients; all were infants. Patients, particularly young children, are at risk for hospital-acquired diarrhea and associated deaths in Bangladeshi hospitals. Further research to identify the responsible organisms and transmission routes could inform prevention strategies.

Isolation of Salmonella Virchow from a fruit bat (Pteropus giganteus).

Detection of zoonotic pathogens carried by bats is important both for understanding disease ecology and for developing preventive measures. Pteropus fruit bats have been identified as potential carriers of Salmonella enterica serotype Typhi. A cross-sectional study was conducted to determine the prevalence of Salmonella Typhi and other Salmonella serotypes in Pteropus giganteus fruit bats in Bangladesh. Rectal swabs were collected from 302 bats and cultured for Salmonella species. The bats were trapped in three districts (Faridpur, Rajbari, and Cox's Bazar). Salmonella Typhi was not found but one juvenile female bat from Faridpur district was positive for Salmonella Virchow. Close associations between frugivorous bats, humans, and livestock in rural Bangladesh make it likely that the bat was infected by consuming contaminated water.

A randomized controlled trial of interventions to impede date palm sap contamination by bats to prevent nipah virus transmission in Bangladesh.

BACKGROUND: Drinking raw date palm sap is a risk factor for human Nipah virus (NiV) infection. Fruit bats, the natural reservoir of NiV, commonly contaminate raw sap with saliva by licking date palm's sap producing surface. We evaluated four types of physical barriers that may prevent bats from contacting sap. METHODS: During 2009, we used a crossover design and randomly selected 20 date palm sap producing trees and observed each tree for 2 nights: one night with a bamboo skirt intervention applied and one night without the intervention. During 2010, we selected 120 trees and randomly assigned four types of interventions to 15 trees each: bamboo, dhoincha (local plant), jute stick and polythene skirts covering the shaved part, sap stream, tap and collection pot. We enrolled the remaining 60 trees as controls. We used motion sensor activated infrared cameras to examine bat contact with sap. RESULTS: During 2009 bats contacted date palm sap in 85% of observation nights when no intervention was used compared with 35% of nights when the intervention was used [p<0.001]. Bats were able to contact the sap when the skirt did not entirely cover the sap producing surface. Therefore, in 2010 we requested the sap harvesters to use larger skirts. During 2010 bats contacted date palm sap [2% vs. 83%, p<0.001] less frequently in trees protected with skirts compared to control trees. No bats contacted sap in trees with bamboo (p<0.001 compared to control), dhoincha skirt (p<0.001) or polythene covering (p<0.001), but bats did contact sap during one night (7%) with the jute stick skirt (p<0.001). CONCLUSION: Bamboo, dhoincha, jute stick and polythene skirts covering the sap producing areas of a tree effectively prevented bat-sap contact. Community interventions should promote applying these skirts to prevent occasional Nipah spillovers to human.