Epizootic ulcerative syndrome,
Information received on 24/07/2020 from Dr Patrick Chikungwa, Director of Department of Animal Health and Livestock Development, Department of Animal Health and Livestock Development, Ministry of Agriculture, Irrigation an Water Development, LILONGWE, Malawi
Report type Immediate notification
Date of start of the event 16/06/2020
Date of confirmation of the event 17/07/2020
Report date 24/07/2020
Date submitted to OIE 24/07/2020
Reason for notification First occurrence of a listed disease in the country
Causal agent Aphanomyces invadans
Nature of diagnosis Suspicion, Clinical, Laboratory (basic), Necropsy
This event pertains to a defined zone within the country
Related reports Immediate notification (24/07/2020)
Follow-up report No. 1 (04/08/2020)
Follow-up report No. 2 (11/08/2020)
Follow-up report No. 3 (26/08/2020)
Follow-up report No. 4 (21/09/2020)
Follow-up report No. 5 (28/10/2020)
New outbreaks (1)
Outbreak 1 Bua river, Mlonyeni EPA, Mchinji, Central
Date of start of the outbreak 16/06/2020
Outbreak status Continuing (or date resolved not provided)
Epidemiological unit River system
Water type Fresh water
Population type Wild
Production system Open
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
Cat fish (Clarias gariepinus) (kg) 3 (scale 0 to 5) 3 (scale 0 to 5) 1000 5 5 0 0
Affected population The affected fish are mostly from the river Bua and a connecting river with other ponds constructed by farmers in the swampy areas that drain the rivers. Most affected are Clarias species and some Oreochromis Shiranus and Tilapia spp.
Summary of outbreaks Total outbreaks: 1
Total animals affected
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
Cat fish (Clarias gariepinus) (kg) 1000 5 5 0 0
Outbreak statistics
Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Cat fish (Clarias gariepinus) (kg) 0.50% 0.50% 100.00% 0.50%
*Removed from the susceptible population through death, destruction and/or slaughter
Source of the outbreak(s) or origin of infection
  • Contact with infected neighbouring establishment
  • Fomites (humans, vehicles, feed, etc.)
  • Horizontal spread through water
Epidemiological comments There are fishing activities done in these rivers with use of different fishing gears from different sources. A lot of small scale fish farming done in the swampy areas are close to the rivers and farmers might have illegally sourced fingerlings from infected zones within the neighboring establishments across the borders. Preliminary analysis was done at Central Veterinary Laboratory and samples have been sent to University of Zambia for molecular analysis.
Control measures
Measures applied
  • Emergency harvest
  • Surveillance within infected and/or protection zone
  • Surveillance outside infected and/or protection zone
  • Movement control inside the country
  • Vaccination permitted (if a vaccine exists)
  • No treatment of affected animals
Measures to be applied
  • Process to inactivate the pathogenic agent in products or by-products
  • Disinfection
  • Quarantine
Diagnostic test results
Laboratory name and type Species Test Test date Result
Central Veterinary Laboratory (National laboratory) Cat fish (Clarias gariepinus) microscopic examination 17/07/2020 Positive
University of Zambia (ACEIDHA) (Regional Reference Laboratory) Cat fish (Clarias gariepinus) polymerase chain reaction (PCR) Pending
Future Reporting
The event is continuing. Weekly follow-up reports will be submitted.
Map of outbreak locations