The World Health Organization reported on Monday that five countries in East and southern Africa are currently experiencing outbreaks of the anthrax disease. This year alone, there have been over 1,100 suspected cases and 20 deaths related to the disease in these regions.

In Kenya, Malawi, Uganda, Zambia, and Zimbabwe, there have been a combined 1,166 suspected cases reported. According to the World Health Organization (WHO), 37 of these cases have been confirmed through laboratory testing. The WHO also noted that these five countries experience seasonal outbreaks every year, with Zambia currently facing its worst outbreak since 2011 and Malawi reporting its first human case this year. Thirteen deaths have been reported in Uganda.

Anthrax primarily impacts farm animals such as cattle, sheep, and goats, as well as wild plant-eating animals. People can contract the disease through contact with infected animals or contaminated animal products. While human-to-human transmission of anthrax is uncommon, the World Health Organization reports a few isolated instances.

The disease anthrax is caused by bacteria that can form spores. In 2001, there were attacks in the United States where the weaponized version of anthrax was used. These attacks resulted in five deaths and 17 people becoming ill after being exposed to anthrax spores through letters sent in the mail.

The bacteria that causes anthrax can be found naturally in soil as well.

In a separate evaluation of the Zambia outbreak, deemed the most alarming, the World Health Organization (WHO) reported 684 possible cases in the southern African country as of November 20, resulting in four fatalities. Nine out of Zambia’s 10 provinces have confirmed human cases of anthrax. One particular case involved 26 individuals who may have contracted the illness from consuming contaminated hippopotamus meat.

According to WHO, there is a strong likelihood that the Zambian outbreak will spread to surrounding countries.

The World Health Organization (WHO) stated that the spread of disease in all five countries is most likely caused by a combination of various factors such as extreme weather conditions, lack of access to food, underestimation of risk, and contact with infected animals through handling their meat.