Shigella Infections in Household Contacts of Pediatric Shigellosis Patients in Rural Bangladesh.

Christine Marie George,Sharmin J Luna,Abu S.G Faruque,Lauren Oldja,Jamie Perin,R Bradley Sack,Trisheeta N Hasan,Tahmina Parvin,Ishrat J Azmi,David A Sack,O Colin Stine,Mohammad Shahnaij,Xiaotong Zhang,Kaisar A Talukder,Fatema Akter,Edward Bouwer,Shahnawaz Ahmed,Subhra Chakraborty,Sazzadul Islam Bhuyian

doi:10.3201/eid2111.150333

Abstract

To examine rates of Shigella infections in household contacts of pediatric shigellosis patients, we followed contacts and controls prospectively for 1 week after the index patient obtained care. Household contacts of patients were 44 times more likely to develop a Shigella infection than were control contacts (odds ratio 44.7, 95% CI 5.5–361.6); 29 (94%) household contacts of shigellosis patients were infected with the same species and serotype as the index patient’s. Pulsed-field gel electrophoresis showed that 14 (88%) of 16 with infected contacts had strains that were indistinguishable from or closely related to the index patient’s strain. Latrine area fly counts were higher in patient households compared with control households, and 2 patient household water samples were positive for Shigella. We show high susceptibility of household contacts of shigellosis patients to Shigella infections and found environmental risk factors to be targeted in future interventions.

Highlights

In South Asia and Africa, an estimated 88.5 million diarrhea episodes are attributed to Shigella infections annually [1]
Of 88 shigellosis–patient household contacts and 81 control household contacts who were screened for eligibility, 5 (6%) and 4 (5%), respectively, were excluded from the study because they did not pass stool on visit 1
We found that the odds of developing a Shigella infection were >44 times higher for contacts of pediatric shigellosis patients than for control contacts

Summary

Introduction

In South Asia and Africa, an estimated 88.5 million diarrhea episodes are attributed to Shigella infections annually [1]. Studies in rural [8] and urban [9] Bangladesh found that 75% and 72%, respectively, of infected household contacts of shigellosis patients excreted serotypes different from the index patient’s serotype. These studies suggest that Shigella infections in Bangladesh are attributable to both secondary transmission and external infecting sources. To examine the rate of Shigella infection within households of shigellosis patients and to investigate risk factors for infection, we prospectively observed a cohort of household contacts of pediatric shigellosis patients and community controls in rural Mirzapur, Bangladesh

Methods

Results

Conclusion