Environmental and Climatic Factors Associated with Epizootic Ulcerative Syndrome (EUS) in Fish from the Zambezi Floodplains, Zambia

Choongo, Kennedy; Hang’ombe, Bernard M.; Samui, K.L.; Syachaba, M.; Phiri, Harris; Maguswi, C.; Muyangaali, K.; Bwalya, G.; Mataa, Liywalii

doi:10.1007/s00128-009-9799-0

Cited by 27 publications

(35 citation statements)

References 9 publications

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“…A number of predisposing factors leading to infection have been identified (Baldock et al 2005;Choonga et al 2009). Disease often manifests when water temperatures drop (Baldock et al 2005), possibly as a consequence of a retarded immune response in the fish.…”

Section: Discussionmentioning

confidence: 98%

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Epizootic ulcerative syndrome: Exotic fish disease threatens Africa’s aquatic ecosystems

Huchzermeyer

Waal

2012

J. S. Afr. Vet. Assoc.

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In late 2006 an unusual ulcerative condition in wild fish was reported for the first time in Africa from the Chobe and upper Zambezi Rivers in Botswana and Namibia. Concern increased with subsistence fishermen reporting large numbers of ulcerated fish in their catches. In April 2007 the condition was confirmed as an outbreak of epizootic ulcerative syndrome (EUS). The causative agent, Aphanomyces invadans, is a pathogenic water mould of fish that shows little host specificity. Ulcers follow infection of tissues by oomycete zoospores, resulting in a granulomatous inflammation associated with invading oomycete hyphae. Granulomatous tracts surrounding oomycete hyphae within the necrotic tissues characterise the diagnostic histological picture. The upper Zambezi floodplain at the confluence with the Chobe River spans the four countries of Botswana, Namibia, Zambia and Zimbabwe, making disease control a challenge. The floodplain ecosystem supports a high fish diversity of around 80 species, and is an important breeding and nursery ground. The annual cycle of flooding brings about changes in water quality that are thought to favour the infectivity of A. invadans, with diseased fish appearing soon after the plains become flooded. Since 2006 the disease has spread rapidly upstream along the upper Zambezi and its tributaries. By 2010 the disease was reported from the Okavango Delta in Botswana and in 2011 from the Western Cape Province of South Africa. EUS has the potential to disrupt floodplain ecosystems elsewhere in Africa where high fish diversity forms the basis of subsistence fisheries and local economies, and is a direct threat to freshwater fish culture.

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Section: Discussionmentioning

confidence: 98%

“…Reports from Zambia have indicated a rapid spread upstream in the Zambezi River and some of its tributaries, in some cases associated with large-scale fish mortality (Anon 2009;Choonga et al 2009;Songe et al 2012). So far EUS has not been reported from the Zambezi River downstream of Victoria Falls.…”

Section: Sargochromis Giardi Pink Breammentioning

confidence: 94%

Epizootic ulcerative syndrome: Exotic fish disease threatens Africa’s aquatic ecosystems

Huchzermeyer

Waal

2012

J. S. Afr. Vet. Assoc.

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“…In Zambia, fish is the most affordable source of animal protein for many people (Choongo et al 2009). Many communities living along the rivers and lakes in Southern Africa and Zambia, in particular, have enjoyed fish without any worries of aquatic diseases.…”

Section: Introductionmentioning

confidence: 99%

Field observations of fish species susceptible to epizootic ulcerative syndrome in the Zambezi River basin in Sesheke District of Zambia

Songe¹,

Hang’ombe

Phiri³

et al. 2011

Trop Anim Health Prod

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A field investigation was conducted in the Sesheke District of Zambia along the Zambezi River to determine the fish species susceptible to epizootic ulcerative syndrome (EUS), a newly confirmed disease in Southern Africa. A total of 2,132 fishes were inspected for gross EUS-like lesions, of which 188 (8.82%; 95% CI=7.67-10.1%) were found with typical characteristic lesions of EUS. Of these 188 samples, 156 were found to have mycotic granulomas on histopathological analysis, representing 83.0% (95% CI=76.7-87.9%) of the initially identified in the laboratory through gross examination. The following 16 species of fish were examined and found with EUS lesions; Clarias ngamensis, Clarias gariepinus, Barbus poechii, Tilapia sparrmanii, Serranochromis angusticeps, Brycinus lateralis, Micralestes acutidens, Sargochromis carlottae, Hydrocynus vittatus, Phryngochromis acuticeps, Schilbe intermedius, Hepsetus odoe, Labeo lunatus, Oreochromis andersonii, Barbus unitaeniatus, and Barbus paludinosus. T. sparrmanii did not show any lesions, while the Clarias species were found to be the most afflicted with EUS. These results could be useful to fish farmers and organizations interested in improving aquaculture in the area.

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“…In sub-Saharan Africa the first report of A. invadans and an associated EUS outbreak was from Botswana in 2007, followed by Zambia in 2008 (Andrew et al 2008). Subsequently 27 fish species from the region have been shown to be susceptible to EUS (FAO 2009;Choongo et al 2009;Songe et al 2012;Huchzermeyer & Van der Waal 2012). Lesions, suspected to be associated with EUS have previously been reported from Lake Liambezi by Van der Waal (2008;.…”

mentioning

confidence: 88%

Histological Confirmation of Epizootic Ulcerative Syndrome in Two Cyprinid Species from Lake Liambezi, Zambezi Region, Namibia

McHugh¹,

Christison²,

Weyl

et al. 2014

African Zoology

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Environmental and Climatic Factors Associated with Epizootic Ulcerative Syndrome (EUS) in Fish from the Zambezi Floodplains, Zambia

Cited by 27 publications

References 9 publications

Epizootic ulcerative syndrome: Exotic fish disease threatens Africa’s aquatic ecosystems

Epizootic ulcerative syndrome: Exotic fish disease threatens Africa’s aquatic ecosystems

Field observations of fish species susceptible to epizootic ulcerative syndrome in the Zambezi River basin in Sesheke District of Zambia

Histological Confirmation of Epizootic Ulcerative Syndrome in Two Cyprinid Species from Lake Liambezi, Zambezi Region, Namibia

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