Disease killing fish in Zambezi River risks spreading to other parts of Africa, UN warns

21 July - A deadly disease devastating fish stocks in Africa's Zambezi River basin and threatening the livelihoods and access to food of millions of rural people could soon reach other parts of the continent, the United Nations Food and Agriculture Organization (FAO) warned today.

The most affected country is Zambia, covering two-thirds of the basin's almost 1.4 million square kilometres, with over 2,000 villages and some 7,000 people now at risk of hunger as fish is a major source of income in many rural districts and the cheapest source of protein, said FAO.

The disease, called Epizootic Ulcerative Syndrome (EUS), is caused by a fungus forming deep lesions on fish and results in high mortality rates.

Although fish infected with EUS do not normally pose a threat to humans, the ugly lacerations render them unmarketable, threatening some 25 million people dependent on agriculture or fishing and fish farming in the Zambezi River basin with serious economic loss.

“If not properly contained there is the risk of the disease spreading to other countries surrounding the Zambezi River as well as river systems in the region,” said Rohana Subasinghe, FAO Senior Fishery Resources Officer.

Indications are that EUS, which was first confirmed in Africa in 2007, is spreading both upstream and downstream of the Zambezi and risks taking hold in other parts of Africa, FAO said in a news release.

Since 2007, FAO has bolstered defenses in the seven Zambezi River basin countries – Angola, Botswana, Malawi, Mozambique, Namibia, Zambia and Zimbabwe – against the disease, with measures including basic diagnosis, targeted surveillance and aquatic animal health management.

In cooperation with the World Organization for Animal Health (OIE), FAO is establishing a programme to strengthen institutional and human ability for managing aquatic animal health in the wild in the affected Southern African countries.

EUS, now present in at least 24 countries worldwide, first appeared in Japan in the early 1970s and then spread to Australia and much of Asia, while the United States was hit in 1984.

FAO said that controlling EUS in natural waters is an impossible task, but in fish farming operations a number of simple bio-security measures – preventing possible carriers getting into water bodies or fish ponds, removing dead fish and improving water quality – can minimize its spread.