Epizootic ulcerative synd., fish - Southern Africa: (Zambezi River)

EPIZOOTIC ULCERATIVE SYNDROME, FISH - SOUTHERN AFRICA: (ZAMBEZI RIVER)
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International Society for Infectious Diseases
<http://www.isid.org>

Date: Tue 21 Jul 2009
Source: FAO/GIEWS (Global Information and Early Warning System on
Food and Agriculture), Special Alert No 327, Southern Africa, Zambezi River [edited]
<http://www.fao.org/docrep/012/ak335e/ak335e00.htm>


A fish disease threatens the livelihoods and food security of millions who depend on fisheries from the Zambezi River Valley
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Millions of people inhabiting the Zambezi River Valley and depending on fishery resources are at risk of losing their livelihoods and important source of protein due to the outbreak of a fish disease called epizootic ulcerative syndrome (EUS). The disease is caused by the fungus _Aphanomyces invadans_; it forms ugly lesions on the fish, which makes it unappealing for consumers [see Figure 1 at the URL above]. Although EUS-infected fish do not pose human health hazards for consumers, it is not recommended for human consumption unless proper precautions are taken.

EUS has now been confirmed in 3 countries in Africa (Zambia, Namibia, and Botswana; Figure 2 at the URL above) with some 20 freshwater food fish species added to the list of more than 50 species susceptible to EUS. The Text Box below [see cited in the commentary) shows an informal assessment of the current situation in Zambia. If not properly contained, there is the risk of the disease spreading to other countries surrounding the Zambezi River as well as other river systems in the region. Continuous occurrence of EUS may also negatively impact biodiversity of the Zambezi River, which is home to more than 200 fish species, some of which are endemic to the river, and many of which are fished heavily for food. Scientists fear that the infection may further spread into the Lake Kariba system threatening food security in the area.

This disease is not unique to Africa. In the early 1970s, it swept across many countries of Asia, Australia , and the United States of America , causing significant loss of income to fishers and fish farmers and adversely affecting biodiversity.

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Communicated by:
ProMED-mail Rapporteur Susan Baekeland

[The following informal assessment of the current situation in Zambia is included in the FAO special alert above:
(Source: Dr Bernard Mudenda, School of Veterinary Medicine, University of Zambia).

The Case of Zambia: an informal assessment of the current situation
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- There have been four outbreaks in Zambia since 2006. In 2006, the outbreak was in Sesheke district, in 2007 in Mongu plains, in 2008 in Zambezi and Chavuma and currently in Mwinilunga, including the Kabompo river system, where disease was not present before.

- The number of villages affected could well be over 2000 as the river systems sustains 2 big provinces of Zambia and all the districts and settlements are on the river banks, affecting possibly about 700 000 people.

- The entire population in the above mentioned areas depend on fishing activities and could face food insecurity. In 2007, Senanga district estimated the lost revenues from Fish levies at about USD 6000 in 3 months. This is a rural district depending mainly on fishing activities, where fish is the cheapest source of protein. These are also HIV-AIDS affected areas."

Detailed information on EUS is available in chapter 2.1.10. of OIE's Manual of Diagnostic Tests for Aquatic animals 2006, available at http://oie.int/eng/normes/fmanual/A_00027.htm. The chapter includes, among others, information for the design of surveillance programmes, diagnostic methods and 20 references. - Mod.AS]

[The Zambezi River basin can be seen on the map at <http://en.wikipedia.org/wiki/Zambezi>. - Sr.Tech.Ed.MJ]