Zambia is experiencing its worst anthrax outbreak in a decade, while four neighbouring countries – Kenya, Malawi, Uganda and Zimbabwe – have also reported outbreaks, according to the World Health Organization’s (WHO) Africa region.

By 20 November, four Zambians had died, with 684 suspected and 37 confirmed cases from nine of the country’s 10 provinces. Twenty-six people developed sores on their faces, arms, and fingers after eating the meat from three wild hippopotamus carcasses.

Beyond Zambia, a further 482 suspected cases have been identified, according to the WHO. Thirteen people have died in Uganda, three people have died in Kenya, and one in  Malawi. 

Kenya, Zambia, Malawi, Uganda & Zimbabwe are currently experiencing anthrax outbreaks, with over 1,100 suspected cases & 20 deaths reported. pic.twitter.com/2RZ1YoLQHO

— WHO African Region (@WHOAFRO) December 11, 2023

Anthrax is a zoonotic disease caused by a bacteria that occurs naturally in soil and mostly affects ruminants such as cows, sheep and goats. Humans develop the disease from infected animals or contaminated animal products, and almost always need to be hospitalised after infection as it causes serious illness.

People can start showing symptoms within hours or up to three weeks after exposure. By far the most common presentation is cutaneous (skin), with itchy bumps that rapidly develop into black sores. Some people then develop headaches, muscle aches, fever, and vomiting. These cases originate from people handling infected carcasses, hides, hair, meat or bones.

Gastrointestinal anthrax causes initial symptoms similar to food poisoning but can worsen to produce severe abdominal pain, vomiting of blood and severe diarrhoea.

Pulmonary anthrax is the most serious form, initially presenting as a common cold but can rapidly progress to severe breathing difficulties and shock. 

High risk of regional spread

“Due to the scale of the outbreak in Zambia, shared ecosystem with neighbouring countries and frequent cross-border animal and human movement, there is a heightened risk of regional spread of the disease,” according to WHO.

Anthrax cases are already spreading in areas along the basin of the Zambezi, Kafue, and Luangwa rivers.  Carcasses of wild animals that float on the rivers also increase the risk of international spread to neighbouring countries. 

“To end these outbreaks we must break the cycle of infection by first preventing the disease in animals. We are supporting the ongoing national outbreak control efforts by providing expertise as well as reinforcing collaboration with partner agencies for a common approach to safeguard human and animal health,” said Dr Matshidiso Moeti, WHO’s Africa Director. 

There is a vaccine for people and animals but there is limited stock, according to WHO. The Zambian government has vaccinated more than 122,000 cattle, sheep and goats with support from Food and Agricultural Organization (FAO).

A joint One Health task force comprising the Ministries of Health and Local Government has been conducting case finding in animals and humans. The country’s veterinary department is conducting meat inspections in abattoirs and butcher shops, while the Department of Wildlife and Parks is monitoring illegal animal movements and ensuring proper disposal of carcasses. 

“The outbreaks are likely being driven by multiple factors, including climatic shocks, food insecurity, low risk perception and exposure to the disease through handling the meat of infected animals,” according to the WHO.

Image Credits: Gavi.