Household-level risk factors for secondary influenza-like illness in a rural area of Bangladesh

This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Objective To describe household‐level risk factors for secondary influenza‐like illness (ILI), an important public health concern in the low‐income population of Bangladesh. Methods Secondary analysis of control participants in a randomised controlled trial evaluating the effect of handwashing to prevent household ILI transmission. We recruited index‐case patients with ILI – fever (<5 years); fever, cough or sore throat (≥5 years) – from health facilities, collected information on household factors and conducted syndromic surveillance among household contacts for 10 days after resolution of index‐case patients’ symptoms. We evaluated the associations between household factors at baseline and secondary ILI among household contacts using negative binomial regression, accounting for clustering by household. Results Our sample was 1491 household contacts of 184 index‐case patients. Seventy‐one percentage reported that smoking occurred in their home, 27% shared a latrine with one other household and 36% shared a latrine with >1 other household. A total of 114 household contacts (7.6%) had symptoms of ILI during follow‐up. Smoking in the home (RRadj 1.9, 95% CI: 1.2, 3.0) and sharing a latrine with one household (RRadj 2.1, 95% CI: 1.2, 3.6) or >1 household (RRadj 3.1, 95% CI: 1.8–5.2) were independently associated with increased risk of secondary ILI. Conclusion Tobacco use in homes could increase respiratory illness in Bangladesh. The mechanism between use of shared latrines and household ILI transmission is not clear. It is possible that respiratory pathogens could be transmitted through faecal contact or contaminated fomites in shared latrines

Respiratory Viruses Associated Hospitalization among Children Aged <5 Years in Bangladesh: 2010-2014.

BACKGROUND:We combined hospital-based surveillance and health utilization survey data to estimate the incidence of respiratory viral infections associated hospitalization among children aged < 5 years in Bangladesh. METHODS:Surveillance physicians collected respiratory specimens from children aged <5 years hospitalized with respiratory illness and residing in the primary hospital catchment areas. We tested respiratory specimens for respiratory syncytial virus, parainfluenza viruses, human metapneumovirus, influenza, adenovirus and rhinoviruses using rRT-PCR. During 2013, we conducted a health utilization survey in the primary catchment areas of the hospitals to determine the proportion of all hospitalizations for respiratory illness among children aged <5 years at the surveillance hospitals during the preceding 12 months. We estimated the respiratory virus-specific incidence of hospitalization by dividing the estimated number of hospitalized children with a laboratory confirmed infection with a respiratory virus by the population aged <5 years of the catchment areas and adjusted for the proportion of children who were hospitalized at the surveillance hospitals. RESULTS:We estimated that the annual incidence per 1000 children (95% CI) of all cause associated respiratory hospitalization was 11.5 (10-12). The incidences per 1000 children (95% CI) per year for respiratory syncytial virus, parainfluenza, adenovirus, human metapneumovirus and influenza infections were 3(2-3), 0.5(0.4-0.8), 0.4 (0.3-0.6), 0.4 (0.3-0.6), and 0.4 (0.3-0.6) respectively. The incidences per 1000 children (95%CI) of rhinovirus-associated infections among hospitalized children were 5 (3-7), 2 (1-3), 1 (0.6-2), and 3 (2-4) in 2010, 2011, 2012 and 2013, respectively. CONCLUSION:Our data suggest that respiratory viruses are associated with a substantial burden of hospitalization in children aged <5 years in Bangladesh

Highly Pathogenic Avian Influenza A(H5N1) Virus Infection among Workers at Live Bird Markets, Bangladesh, 2009–2010

The risk for influenza A(H5N1) virus infection is unclear among poultry workers in countries where the virus is endemic. To assess H5N1 seroprevalence and seroconversion among workers at live bird markets (LBMs) in Bangladesh, we followed a cohort of workers from 12 LBMs with existing avian influenza surveillance. Serum samples from workers were tested for H5N1 antibodies at the end of the study or when LBM samples first had H5N1 virus–positive test results. Of 404 workers, 9 (2%) were seropositive at baseline. Of 284 workers who completed the study and were seronegative at baseline, 6 (2%) seroconverted (7 cases/100 poultry worker–years). Workers who frequently fed poultry, cleaned feces from pens, cleaned food/water containers, and did not wash hands after touching sick poultry had a 7.6 times higher risk for infection compared with workers who infrequently performed these behaviors. Despite frequent exposure to H5N1 virus, LBM workers showed evidence of only sporadic infection

Impact of Intensive Handwashing Promotion on Secondary Household Influenza-Like Illness in Rural Bangladesh: Findings from a Randomized Controlled Trial

<div><p>Rationale</p><p>There is little evidence for the efficacy of handwashing for prevention of influenza transmission in resource-poor settings. We tested the impact of intensive handwashing promotion on household transmission of influenza-like illness and influenza in rural Bangladesh.</p><p>Methods</p><p>In 2009–10, we identified index case-patients with influenza-like illness (fever with cough or sore throat) who were the only symptomatic person in their household. Household compounds of index case-patients were randomized to control or intervention (soap and daily handwashing promotion). We conducted daily surveillance and collected oropharyngeal specimens. Secondary attack ratios (SAR) were calculated for influenza and ILI in each arm. Among controls, we investigated individual risk factors for ILI among household contacts of index case-patients.</p><p>Results</p><p>Among 377 index case-patients, the mean number of days between fever onset and study enrollment was 2.1 (SD 1.7) among the 184 controls and 2.6 (SD 2.9) among 193 intervention case-patients. Influenza infection was confirmed in 20% of controls and 12% of intervention index case-patients. The SAR for influenza-like illness among household contacts was 9.5% among intervention (158/1661) and 7.7% among control households (115/1498) (SAR ratio 1.24, 95% CI 0.92–1.65). The SAR ratio for influenza was 2.40 (95% CI 0.68–8.47). In the control arm, susceptible contacts <2 years old (RR_adj 5.51, 95% CI 3.43–8.85), those living with an index case-patient enrolled ≤24 hours after symptom onset (RR_adj 1.91, 95% CI 1.18–3.10), and those who reported multiple daily interactions with the index case-patient (RR_adj 1.94, 95% CI 1.71–3.26) were at increased risk of influenza-like illness.</p><p>Discussion</p><p>Handwashing promotion initiated after illness onset in a household member did not protect against influenza-like illness or influenza. Behavior may not have changed rapidly enough to curb transmission between household members. A reactive approach to reduce household influenza transmission through handwashing promotion may be ineffective in the context of rural Bangladesh.</p><p>Trial Registration</p><p>ClinicalTrials.gov <a href="http://clinicaltrials.gov/ct2/show/NCT00880659?term=NCT00880659&rank=1" target="_blank">NCT00880659</a></p></div

Impact of intensive handwashing promotion on secondary attack risks (SAR) of influenza-like illness, and influenza, among household compound members of index case-patients, Kishoregonj, Bangladesh, 2009–2010.

<p>*All susceptible contacts in both index case-patient and secondary households included.</p><p>**Confidence intervals and P-values generated using log binomial regression model with generalized estimating equations to estimate significance of ratio of secondary attack risks in treatment arms.</p><p>Impact of intensive handwashing promotion on secondary attack risks (SAR) of influenza-like illness, and influenza, among household compound members of index case-patients, Kishoregonj, Bangladesh, 2009–2010.</p

Individual-level risk factors for secondary transmission of influenza-like illness among susceptible household members in the control arm, Kishoregonj, Bangladesh, 2009–2010 (N = 1498).

<p>¹ Attack rates for influenza-like illness calculated for susceptible members in the control arm who were exposed and unexposed to each characteristic at baseline. Attack rate ratios and confidence intervals generated using log binomial regression models, with generalized estimating equations to account for clustering among household members.</p><p>^<b>2</b>Analysis restricted to household members of index case-patients > 5 years old.</p><p>^<b>3</b>Information missing for 295 household members.</p><p>^<b>4</b>Only queried in 2010.</p><p>^<b>5</b>Only reported for members of index case-patient household.</p><p># multivariable model includes the following variables: contact < 2 years old (or contact < 5 years old); Index case-patient with fever onset 24 hours prior to enrollment; and contact interacts multiple times daily with index case-patient.</p><p>Individual-level risk factors for secondary transmission of influenza-like illness among susceptible household members in the control arm, Kishoregonj, Bangladesh, 2009–2010 (N = 1498).</p

Multivariable analysis of impact of intensive handwashing promotion on secondary attack risks (SAR) of influenza-like illness, and influenza, among household compound members of index case-patients, Kishoregonj, Bangladesh, 2009–2010.

<p>Multivariable analysis of impact of intensive handwashing promotion on secondary attack risks (SAR) of influenza-like illness, and influenza, among household compound members of index case-patients, Kishoregonj, Bangladesh, 2009–2010.</p

Baseline characteristics of index case-patients, household compounds, and household members, by treatment arm, Kishoregonj, Bangladesh, 2009–2010.

<p>*Data not collected for 67 children, all of whom were under 5 years old and enrolled in 2009.</p><p>**Only queried in 2010; denominators were 934 for intervention arm and 890 for control arm.</p><p>***Only reported for members of index case-patient household; denominators were 863 in the intervention arm and 727 in the control group.</p><p>Baseline characteristics of index case-patients, household compounds, and household members, by treatment arm, Kishoregonj, Bangladesh, 2009–2010.</p

Flow diagram to describe screening, inclusion, exclusion, and randomization, Kishoregonj, Bangladesh, 2009–2010.

<p>Flow diagram to describe screening, inclusion, exclusion, and randomization, Kishoregonj, Bangladesh, 2009–2010.</p