On Nov. 1, 2023, the International Health Regulations (IHR) National Focal Point of Zambia notified the World Health Organization (WHO) of an anthrax outbreak in humans. The first human cases were reported from the Dengeza Health Post in the Sinazongwe District of the Southern Province on 5 May 2023.

Around the same time period, domestic (cattle and goats) and wild animals (hippopotami) were reportedly dying from an unknown cause in the surrounding areas. In June 2023, human and animal cases were reported in the Kanchindu and Siameja veterinary camps of Sinazongwe District. Twenty-six human cases developed sores on their face, arms, and fingers after consuming meat from three wild hippopotamus carcasses.

The first human case was reported on 16 June 2023 and laboratory confirmed by culture at the Lusaka Central Veterinary Research Institute (CVRI). As of 20 November 2023, 684 suspected human cases, including four deaths, a Case Fatality Ratio (CFR)of 0.6%, were reported from 44 out of 116 districts in nine of Zambia’s 10 provinces.

Anthrax is a zoonotic disease caused by a bacteria called Bacillus anthracis that typically affects ruminants (such as cows, sheep, and goats). The bacteria produce extremely potent toxins which are responsible for the symptoms, causing a high lethality rate in the pulmonary form. Humans can develop the disease from infected animals or through contaminated animal products. Hospitalization is required for all human cases identified. Vaccines are available for livestock and humans in limited supply.

The risk of the event spreading within Zambia is assessed to be high due to the unrestricted animal movement and carcasses within and between provinces. The risk at the regional level is also considered high due to the frequent movement of both animals and people between Zambia and its neighbouring countries (such as Angola, Botswana, the Democratic Republic of the Congo, Malawi, Mozambique, Namibia, Tanzania, Uganda and Zimbabwe).