Taking care of a diarrhea epidemic in an urban hospital in Bangladesh: Appraisal of putative causes, presentation, management, and deaths averted

Abstract

Background: In April 2018, a diarrhea epidemic broke out in Dhaka city and adjoining areas, which continued through May. The Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), a dedicated diarrheal disease hospital, had a large upsurge in patient visits during the epidemic. An enhanced understanding of the epidemiology of this epidemic may help health-related professionals better prepare for such events in the future. This study examined the microbial etiology and non-pathogen factors associated with diarrhea during the epidemic. The study also evaluated the patients' presentation and clinical course and estimated the potential mortality averted by treating patients during the epidemic.

Methodology/principal findings: Data from the patients who were treated at Dhaka Hospital during the diarrhea epidemic between April 2 and May 12, 2018 and were enrolled into the Diarrheal Disease Surveillance System (DDSS) at icddr,b were compared with the DDSS-enrolled patients treated during the seasonally-matched periods in the flanking years using logistic regression. icddr,b Dhaka Hospital treated 29,212 diarrheal patients during the 2018 epidemic period (and 25,950 patients per comparison period on average). Vibrio cholerae was the most common pathogen isolated (7,946 patients; 27%) and associated with diarrhea during the epidemic (adjusted odds ratio [AOR] 1.5, 95% CI: 1.1-2.0). The interaction of Vibrio cholerae with ETEC (AOR 2.7, 95% CI: 1.3-5.9) or Campylobacter (AOR 2.4, 95% CI: 1.1-5.1) was associated with further increased odds of diarrhea during the epidemic. In children under five years old, rotavirus was the most common pathogen (2,029 patients; 26%). Those who were adolescents (AOR 2.0, 95% CI: 1.3-3.1) and young adults (AOR 1.9, 95% CI: 1.4-2.5) compared to children younger than five years, resided within a 10 km radius of Dhaka Hospital (AOR 1.6, 95% CI: 1.1-2.2) compared to those living outside 20 km, borrowed money or relied on aid to pay for the transport to the hospital (AOR 1.6, 95% CI: 1.2-2.0), used tap water (AOR 1.8, 95% CI: 1.4-2.4) for drinking compared to tubewell water, and disposed of the solid waste directly outside the house (AOR 4.0, 95% CI: 2.7-5.9) were more likely to present with diarrhea during the epidemic. During the epidemic, patients were more likely to present with severe dehydration (odds ratio [OR] 1.6, 95% CI: 1.3-2.0) and require inpatient admission (OR 2.5, 95% CI: 1.9-3.3), intravenous rehydration (OR 1.7, 95% CI: 1.4-2.1), and antibiotics (OR 2.2, 95% CI: 1.8-2.7). The in-hospital case fatality rate was low (13 patients; 0.04%), and the hospital averted between 12,523 and 17,265 deaths during the epidemic.

Conclusions/significance: Vibrio cholerae played the primary role in the 2018 diarrhea epidemic in Dhaka. Campylobacter, enterotoxigenic Escherichia coli, and rotavirus had a secondary role. Adolescents and adults, residents of the metropolitan area, and those who were relatively poor and lacked safe water, sanitation, and hygiene (WASH) practices comprised the most vulnerable groups. Despite the increased disease severity during the epidemic, the case fatality rate was less than 0.1%. icddr,b Dhaka Hospital saved as many as 17,265 lives during the epidemic.

Fig 1. Total patient visits and patients with selected enteric pathogens detected in stool samples per week at icddr,b Dhaka Hospital in 2018.

The horizontal dashed line represents the 90^th percentile of total patient visits per week in 2017 and 2019. The vertical dashed lines indicate the diarrhea epidemic period (April 2 to May 12) in 2018. ETEC, enterotoxigenic Escherichia coli.

Fig 2. Percent distribution of enteric pathogens isolated from DDSS-enrolled patients treated at icddr,b Dhaka Hospital during the epidemic (cases) and the comparison period (controls) by age groups.

The value on top of each column indicates the percentage of samples positive for a particular pathogen. The pathogens (columns) are arranged in decreasing order of prevalence. ETEC, enterotoxigenic Escherichia coli; NTS, non-typhoidal Salmonella.

Fig 3. Percent distribution of types of Vibrio cholerae isolated from the cases (during the epidemic) and the controls (during the comparison period).

No significant difference was found (P = 0.432) in the distribution of Vibrio cholerae types between the two groups on Fisher’s exact test.

Fig 4. Relative effect of selective enteric pathogens on disease severity during the epidemic.

The value in each cell is the age-adjusted odds ratio of a particular attribute of disease severity for a specific pathogen. The cells are coded using a red-yellow-green color gradient. The red end of the spectrum represents increased odds, and the green end represents decreased odds. The darker the shade, the stronger the effect. Asterisk indicates a statistically significant (P < 0.05) odds ratio. The age-adjusted odds ratios and the corresponding P values were obtained from logistic regression models. To simplify the analysis, coinfections were ignored in the models. ETEC, enterotoxigenic Escherichia coli.