Published Date: 2009-07-22 21:00:07
Subject: PRO/AH/EDR> Epizootic ulcerative synd., fish - Southern Africa: (Zambezi River)
Archive Number: 20090722.2593
EPIZOOTIC ULCERATIVE SYNDROME, FISH - SOUTHERN AFRICA: (ZAMBEZI RIVER)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
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
A fish disease threatens the livelihoods and food security of
millions who depend on fisheries from the Zambezi River Valley
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.
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
- 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
The chapter includes, among others, information for the design of
surveillance programmes, diagnostic methods and 20 references. -
[The Zambezi River basin can be seen on the map at
<http://en.wikipedia.org/wiki/Zambezi>. - Sr.Tech.Ed.MJ]