HQ Team
December 9, 2023: An “unprecedented” outbreak of anthrax, with 684 suspected human cases, has been reported from Zambia, according to the WHO.
As of November 20, 2023, 684 suspected human cases, including four deaths, and a case fatality ratio of 0.6%, were reported from 44 out of 116 districts in nine of Zambia’s 10 provinces.
“This unprecedented outbreak marks the first major occurrence spanning nine out of 10 country provinces,” according to a WHO statement.
The latest large-scale outbreak reported in Zambia occurred in 2011 with a total of 511 suspected cases.
The first human cases were reported from the Dengeza Health Post in the Sinazongwe District of the Southern Province on May 5, 2023.
Dengeza
All the cases from Dengeza, which were presented at health facilities, had skin sores and ulcers, and some of them developed nonspecific symptoms such as nausea, vomiting, and difficulty breathing.
On 1 November 2023, the International Health Regulations (IHR) National Focal Point of Zambia notified WHO of an anthrax outbreak in humans.
Around the same 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.
Infected hippopotamus
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 June 16, 2023 and laboratory-confirmed by culture at the Lusaka Central Veterinary Research Institute (CVRI).
Sinazongwe district is the epicenter, accounting for 287 cases (42% of the total 684 cases) and two deaths (50% of total the four deaths).
The most affected provinces are the Southern (370 cases; 54 %), Western (88; 13%), Lusaka (82; 12%), Eastern (66; 10%) and Muchinga (47; 7 %) Provinces.
Anthrax is a zoonotic disease caused by a bacteria called Bacillus anthracis that typically affects ruminants — cows, sheep, and goats.
Potent toxins
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. Hospitalisation is required for all human cases identified.
Vaccines in Zambia, which reports sporadic cases of anthrax annually, were available for livestock and humans in limited supply, according to the statement.
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.
WHO stated the risk at the regional level was also considered “high” due to the frequent movement of both animals and people between Zambia and its neighbouring countries — Angola, Botswana, the Democratic Republic of the Congo, Malawi, Mozambique, Namibia, Tanzania, Uganda and Zimbabwe.
Skin abrasions
Anthrax does not spread from animal to animal or human to human. When anthrax spores are ingested from contaminated animal products, inhaled, or enter the body through skin abrasions or cuts, they can germinate, multiply and produce toxins.
A total 338 000 doses of anthrax vaccine have been distributed up to 19 November 2023, according to the WHO.
Vaccination campaigns have been initiated at the outbreak epicentre, Sinazongwe district, and are extended to other affected districts.
