A cutaneous Anthrax outbreak in Koraput District of Odisha-India 2015

Priyakanta Nayak,Basanta K Swain,Kailash C Dash,Arun K Padhi,Kayla F Laserson,Bikash Patnaik,Srinivas R Venkatesh,Shaikh S Hossain,Aakash Shrivastava,Pradeep Khasnobis,Samir V Sodha

doi:10.1186/s12889-019-6787-0

Abstract

BackgroundCutaneous anthrax in humans is associated with exposure to infected animals or animal products and has a case fatality rate of up to 20% if untreated. During May to June 2015, an outbreak of cutaneous anthrax was reported in Koraput district of Odisha, India, an area endemic for anthrax. We investigated the outbreak to identify risk factors and recommend control measures.MethodWe defined a cutaneous anthrax case as skin lesions (e.g., papule, vesicle or eschar) in a person residing in Koraput district with illness onset between February 1 and July 15, 2015. We established active surveillance through a house to house survey to ascertain additional cases and conducted a 1:2 unmatched case control study to identify modifiable risk factors. In case control study, we included cases with illness onset between May 1 and July 15, 2015. We defined controls as neighbours of case without skin lesions since last 3 months. Ulcer exudates and rolled over swabs from wounds were processed in Gram stain in the Koraput district headquarter hospital laboratory.ResultWe identified 81 cases (89% male; median age 38 years [range 5–75 years]) including 3 deaths (case fatality rate = 4%). Among 37 cases and 74 controls, illness was significantly associated with eating meat of ill cattle (OR: 14.5, 95% CI: 1.4–85.7) and with close handling of carcasses of ill animals such as burying, skinning, or chopping (OR: 342, 95% CI: 40.5–1901.8). Among 20 wound specimens collected, seven showed spore-forming, gram positive bacilli, with bamboo stick appearance suggestive of Bacillus anthracis.ConclusionOur investigation revealed significant associations between eating and handling of ill animals and presence of anthrax-like organisms in lesions. We immediately initiated livestock vaccination in the area, educated the community on safe handling practices and recommended continued regular anthrax animal vaccinations to prevent future outbreaks.

Highlights

Cutaneous anthrax in humans is associated with exposure to infected animals or animal products and has a case fatality rate of up to 20% if untreated
Historical review of outbreaks The India Epidemic Intelligence Service (EIS) officer investigating the outbreak reviewed available historical data from the Koraput district Integrated Disease Surveillance Programme (IDSP) to identify demographic, clinical, and seasonal characteristics of suspected cutaneous anthrax outbreaks reported in this area from 2010 to 2014
Historical review of outbreaks From 2010 to 2014, we identified nine outbreaks of anthrax in Koraput with 325 suspected anthrax cases and 5 deaths

Summary

Introduction

Cutaneous anthrax in humans is associated with exposure to infected animals or animal products and has a case fatality rate of up to 20% if untreated. A zoonotic disease caused by Bacillus anthracis, can have a case fatality rate up to 20% if untreated; case fatality reduces to < 1% if treated [1]. Cutaneous anthrax generally develops after direct contact with infected animals or animal products [2]. In South Asia, anthrax is highly endemic in India and Bangladesh where frequent outbreaks and cases are reported among animals and humans despite limited laboratory and epidemiologic capacity. India has the world’s largest livestock population; animal anthrax is reported from several regions of the country [1]

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