Lusaka, Zambia
Lusaka/Geneva: While Zambia typically reports sporadic cases of anthrax annually which is endemic there, an unprecedented outbreak of anthrax this time marks the first major occurrence spanning nine out of 10 country provinces.
As of November 20, 2023, 684 suspected human cases, including four deaths (CFR 0.6%) were reported from 44 out of 116 districts in nine of Zambia’s 10 provinces. Sinazongwe district is the epicentre, 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 (84; 12%), Lusaka (82; 12%), Eastern (66; 10%) and Muchinga (47; 7 %) Provinces. The majority of symptomatic cases were epidemiologically linked to confirmed cases and not tested.
On the animal side, as of November 21, 2023, 568 domestic and wild animal cases were reported across 11 districts in Eastern, Southern, and Western provinces, with (344; 61%) occurring in the Southern province, (132; 23%) in the Muchinga province and (62, 11%) in the Western Province. Wildlife cases, primarily hippos, were reported in the Eastern and Southern provinces.
The epidemic is spreading along the provinces located along the basin of the Zambezi, Kafue, and Luangwa rivers, which is an additional problem because these rivers also flow into Lake Kariba in Zimbabwe, Kahora Bassa in Mozambique and Lake Malawi, and the risk of anthrax transmission to neighbouring countries is increased.
Other affected districts and provinces of Zambia have reported sporadic suspected cases and deaths since June 2023. In addition, the Bacillus anthracis bacteria can form highly resistant spores that survive in the environment for decades.
Although sporadic cases of anthrax are reported yearly in animals and humans across the country, a large-scale outbreak like the current one has not been reported since 2011, when there were 511 suspected human cases.
The World Health Organization (WHO) said today that previous outbreaks in Zambia were largely confined to Northwest and Western provinces, with sporadic cases over the years.
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, WHO said. 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).
Anthrax is controlled through animal vaccination programmes, rapid detection and reporting, quarantine, treatment of sub-clinically affected animals (postexposure prophylaxis) and burning or burial of suspect and confirmed animal cases.
Situation at a Glance
On November 1, 2023, the International Health Regulations (IHR) National Focal Point of Zambia notified 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 May 5, 2023. 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. Twenty-six human cases developed sores on their face, arms, and fingers after consuming meat from three wild hippopotamus carcasses.
WHO said today that response activities have been taken from both human and animal sides, such as active surveillance, case management, laboratory diagnosis, health promotion, and Risk Communication and Community Engagement (RCCE), meat inspection and livestock vaccination.
All the cases presented at health facilities with skin sores and ulcers, and some of them developed nonspecific symptoms (e.g., nausea, vomiting, difficulty in breathing). Human specimens were collected during the investigation and sent to the Lusaka Central Veterinary Research Institute (CVRI) for testing.
Response activities have been taken from both human and animal sides. WHO warned that international travellers to anthrax-endemic countries should be aware of regulations concerning the importation of prohibited animal products, trophies, and souvenirs.
– global bihari bureau
