Anthrax outbreak associated with handling dead meat and contaminated milk, Sierra Leone, May 2022

Abstract

Anthrax is a zoonotic disease that is of public health concern. On May 5, 2022, the National Surveillance Program received a notification of suspected human anthrax cases from Karene District, Sierra Leone. We investigated to confirm the diagnosis, determine the magnitude, and identify possible risk factors. We developed an anthrax outbreak case definition, reviewed health facility records, and interviewed cases and their families to collect demographics, clinical, and exposure data. Swab samples were collected and sent to the laboratory for confirmation using real-time PCR. We conducted an active case search, line-listed contacts, and monitored for 14 days. Five cases of cutaneous anthrax were reported; three were below ten years old, three were females—all cases presented with fever, and three presented with skin lesions and body weakness. Four cases developed symptoms after consuming meat from sheep, which died of unknown causes in Karene District. One case from Kailahun District drank milk bought from a female vendor with skin lesions suggestive of anthrax. We identified 27 contacts with no additional cases detected; none of the contacts developed symptoms, and none of the cases died. This investigation confirmed an anthrax outbreak among humans. Possible epidemic sources are processed meat from dead sheep and the handling of contaminated milk. We recommend strengthening human and animal surveillance.

Keywords: Cutaneous anthrax, Zoonoses Disease, Outbreak, Humans, Sierra Leone