Zambia is investigating wildlife deaths and human exposure linked to an anthrax outbreak in the northern province of Muchinga, where several hippos have died since the outbreak was reported on Aug. 31.
While other wildlife deaths have also been reported, hippos (Hippopotamus amphibius) are the species with the clearest laboratory evidence of anthrax, according to Raymond Hamoonga, Zambia’s national One Health coordinator. So far, 46 hippo deaths have been reported in the affected riverine area, but anthrax has only been confirmed in one animal, he told Mongabay by email.
Hamoonga added that even though current mortality rates don’t indicate a threat to hippo populations, the reported deaths are still “significant enough to warrant intensified surveillance, rapid investigation of new carcasses and continued monitoring of affected populations.”
“The immediate concern is the potential for further wildlife deaths, continued contamination around carcass sites and exposure of livestock and people at the wildlife–livestock–human interface,” Hamoonga said.
He said samples from five buffalo carcasses didn’t test positive for anthrax. Samples from 10 elephants reported since June are being investigated; none have been laboratory-confirmed as containing anthrax.
“Buffalo and elephant deaths should not presently be attributed to anthrax without supporting laboratory evidence,” Hamoonga said.
Anthrax is a zoonotic infectious disease caused by the Bacillus anthracis bacteria, which mainly affects wildlife and livestock. However, humans can become infected when they eat or come into contact with infected animals or contaminated animal products.
On Sept. 10, Zambia’s National Disaster Risk Management Division (DRMD), published an advisory urging people in Muchinga province to refrain from consuming, handling, selling, slaughtering, or distributing meat from animals that could have died from anthrax.
The DRMD said suspected carcasses should be reported immediately to veterinary or wildlife authorities.
Zambia has dealt with anthrax outbreaks before, the most significant one in 2023, when four people died and more than were infected across nine of the country’s 10 provinces.
While laboratory testing and field investigations continue into the current outbreak, Zambian authorities are monitoring the human health situation.
According to Hamoonga, as of Sept. 21, 21 people were suspected of contracting the bacteria in Muchinga. Only one case was laboratory-confirmed, and no deaths were reported at the time of the update. Hamoonga said they suspect carcass-related exposure; some people likely contracted the disease after handling or consuming meat from animals found dead.
“Community cooperation is essential because early reporting allows teams to secure and sample carcasses before they are disturbed or decompose,” Hamoonga said, adding that traditional leaders, community health workers, veterinary and wildlife officers, and local radio stations are involved in the local response.
Government authorities are continuing to monitor human health, treat suspected cases, and intensify wildlife and livestock surveillance including laboratory testing and risk-based livestock vaccination. A national vaccination campaign is currently underway.
Banner image: Hippos in a river in Zambia. Image by Julie Larsen © Wildlife Conservation Society.
