Anthrax outbreak linked to consumption and handling of meat from unexpectedly deceased cattle, Kyotera district, Uganda, June-December 2023.

Background: Anthrax is an infectious zoonotic disease caused by gram-positive, rod-shaped, and spore-forming bacteria known as Bacillus anthracis. It continues to be a disease of public health importance in Uganda, with sporadic outbreaks reported annually in many parts of the country. In November 2023, Kyotera District reported a strange illness, characterized by itching, rash, swelling, and skin lesions which was later confirmed as anthrax. We investigated to assess its magnitude, identify potential exposures, and propose evidence-based control measures.

Methods: A suspected cutaneous anthrax case was an acute onset of skin itching/swelling plus ≥ 2 of: skin reddening, lymphadenopathy, headache, fever or general body weakness. A suspected gastrointestinal anthrax case was an acute onset of ≥ 2 of: abdominal pain, vomiting, diarrhea, mouth lesions or neck swelling. A confirmed anthrax case was a suspected case with Bacillus anthracis PCR-positive results. To identify cases, we reviewed medical records and conducted community active case-finding. We conducted an unmatched case-control study and used logistic regression to identify risk factors of anthrax transmission. Controls were selected at a 1:4 ratio from the same villages as the case-patients.

Results: We identified 63 cases (46 suspected and 17 confirmed); 48 (76%) were male. Of the 63, 55 cases (87%) were cutaneous and 8 (13%) were gastrointestinal, with a mean age of 42 years. Overall attack rate (AR) was 3.1/1,000; males were more affected (AR = 4.5/1,000) than females (AR = 1.5/1,000). Case-fatality rate was 19% (n = 12). Among the 63 cases, 18 (29%) sought care from health facilities; 33 (52%) were managed by traditional healers. The odds of anthrax infection were highest in individuals who both consumed and handled infected meat (OR = 20.9, 95% CI: 8.8-49.8), followed by those who only consumed the meat (OR = 5.81, 95% CI: 2.12-15.9).

Conclusion: The anthrax outbreak in Kyotera District was primarily attributed to the consumption and handling of meat from cattle that had suddenly died. Poor health-seeking behavior and seeking care from traditional healers likely contributed to the high case fatality rate. To prevent future outbreaks, authorities should enforce cattle inspection protocols, expand anthrax vaccination campaigns, and enhance community education on safe meat handling and medical care-seeking practices.