Anthrax outbreak associated with the consumption and handling of carcasses of livestock that suddenly died, Kanungu District, Uganda, June-November 2024.

BACKGROUND

Anthrax is a recurrent zoonosis in Uganda, with 11 outbreaks reported in 2024. On September 17, 2024, the Ministry of Health received reports of two human deaths in Kanungu District, later confirmed as anthrax-the district's first recorded outbreak. We investigated to determine its scope, risk factors, and recommend control measures.

METHODS

We defined a suspected cutaneous anthrax case as an acute onset of skin lesions (papule, vesicle, or eschar) with ≥2 of itching, reddening, lymphadenopathy, fever, or malaise. Suspected gastrointestinal anthrax was onset of abdominal pain with ≥2 of vomiting, diarrhea, fever, or loss of appetite in a Kanungu resident from June-November 2024. Confirmation required Polymerase Chain Reaction (PCR) detection of Bacillus anthracis. In a 1:2 unmatched case-control study, we enrolled all cases and controls from neighboring asymptomatic households in the two most affected sub-counties. Logistic regression was used to identify risk factors for infection.

RESULTS

We identified 90 cases (86 suspected and 4 confirmed); 80% had cutaneous, 11% gastrointestinal, and 9% both forms. Males were more affected (attack rate [AR]=48/100,000) than females (AR = 15/100,000); case fatality rate was 6.7% (6/90). Overall, 10/27 sub-counties were affected, with Bugongi (AR = 257/100,000) being the most affected. Consuming meat from suddenly dead livestock (adjusted odds ratio [aOR]=5.5, 95% CI: 2.7-11), handling carcasses (aOR=8.2, 95% CI: 3.8-18), having a low education level (aOR=6.0, 95% CI: 2.6-14), and being male (aOR=2.3, 95%CI = 1.03-4.9) increased the odds of infection. Notably, 90% of the case-patients purchased the contaminated meat from a single dealer.

CONCLUSION

The outbreak was linked to consuming and handling meat from livestock that died suddenly, underscoring gaps in veterinary inspection and carcass management. Strengthening inspections, enforcing carcass disposal, and targeted community education are essential for prevention.