NAHDIC has been engaged in research activities over the last 20 years and has contributed more than 350 published articles to the scientific community. Research activities at NAHDIC focus on problem solving and generating information and data to support disease control and prevention measures. Research initiatives are conducted with NAHDIC technical partners found both within the country and abroad. This includes collaborations with university students. An average of 30 undergraduate and post-graduate (MSc and PhD) Ethiopian university students conduct their research at NAHDIC per year. Currently, there are about 24 active ongoing research projects. Some of the topics are done on bovine tuberculosis, PPR, CBBP, FMD, BVD, IBR, brucellosis and infectious bronchitis.
Yersiniosis outbreak in rainbow trout at fish farm in Oromia Regional State, Ethiopia
EY Ahmed1, A. Woldeyes2,
T Korra2, G Laval3
1Consultant, 2National Animal Health Diagnostic and Investigation Centre (NAHDIC), 3Trout Fish Farmers P.L.C
This study presents the results of an investigation conducted on an outbreak of Yersiniosis (Enteric red mouth disease) caused by Yersinia ruckeri at a rainbow trout farm situated at Adaba, Oromia Regional State, Ethiopia. Seven diseased rainbow trout fish having average weight 80 – 100 grams and aged 9 months, were brought to the National Animal Health Diagnostic and Investigation Center (NAHDIC) for further examination and laboratory testing. The young sick fish showed clinical signs of darkening of the skin, loss of appetite and gasping at the surface of the water before death. The fish were sacrificed and examined thoroughly externally for the presence of visible lesions. Scrapings were collected from the skin especially from areas around the fins and observed under the stereomicroscope and also under the low power objective of the compound microscope. Bacteriological tests were carried out on samples from the kidney, liver and spleen. It was concluded that the fish were affected by Yersinia ruckeri based on colony morphology during growth on Tryptose Soy Agar (yellow colonies, gram negative and rodshaped) and distinctive biochemical characteristics. Y. ruckeri is identified from sick fish for the first time in Ethiopia. The protozoan parasites Trichodina species were also recovered in large colonies from the skin scrapings and histopathological sections of the gills. The pathological lesions recorded included high degree anaemia of oral and branchial mucosa, congested gills, kidney and spleen and pale liver, congestion, extensive necrosis in the kidney and spleen, and infiltration with inflammatory cells. Antibiogram test conducted on the bacteria showed that the Y. ruckeri strain were susceptible to Oxytetracycline, Furazolidone, Trimethoprim and Streptomycin. This study showed the importance of stress induced by higher temperature and poor water quality associated with infestations by Trichodina species as predisposing factors to bacterial diseases in intensive fish farming practices.
Key words: bacterial culture, histopathology, rainbow trout, Yersinia ruckeri, Trichodina species
Outbreak of Aeromonas hydrophila associated with the parasitic infection Ichthyophthirius multifiliis in pond of African catfish ( Clarias gariepinus ) fingerlings at Sebeta, Ethiopia
Gizat Almaw1, Alemnesh Woldeyes1,Marshet Adugna, Tafesse Koran1, Aynalem Fentie1, Alehegne Wubete1
1National Animal Health Diagnostic and Investigation Center, P.O.Box 04, Sebeta, Ethiopia
Outbreak of a disease was observed on African catfish (Clarias gariepinus ) fin gerlings manifested by white nodules all over the body and hemorrhage in the skin that occurred on June 20, 2011 in an earthen pond at Sebeta, Ethiopia. The outbreak was investigated by using a combination of methods that included clinical observations, gross and histopathology examination and bacterial isolation. On histopathological examination co-infection of Aeromonas hydrophila with Ichthyophthirius multifiliis a holotrichous ciliate, was found to be the cause of the outbreak. In order to control the outbreak, the fish density was reduced and the fish were removed and treated with sodium chloride (3%) and moved to another properly disinfected pond that contains fresh and good quality water. The former pond was drained and left empty for two weeks to dry and then lime was added over it before filling it with water. The sick fish got cured after three weeks and no new case was observed; which may be due to development of immunity or the intervention measures taken to control the problem. This intervention protocols need to be further investigated in a properly designed experiment as a possible control of co-infection of these two pathogens in catfish fingerlings.
Keywords: Aeromonas hydrophila, Co-infection,Ethiopia, Ichthyophthirius multifiliis
Hamere Melaku1, Matios Lakew2 *, Esayas Alemayehu3, Alemayehu Wubie3 and Mersha Chane1
1Faculty of Veterinary Medicine, Gondar University, P.O. Box 196, Gondar, Ethiopia
2National Animal Health Diagnostic and Investigation Center, P.O. Box 04, Sebeta, Ethiopia
3Ethiopian National Fishery and Aquatic Life Research Center, P.O. Box 64, Sebeta, Ethiopia
Isolation and identification of pathogenic fungi from African catfish (Clarias gariepinus) eggs and adults in Ethiopian National Fishery and Aquatic Life Research Center hatchery was conducted from October 2015 to May 2016. The aim of this study was to investigate the aquatic fungal flora associated with eggs and brood stock from African catfish in the center. A total of 32 g of eggs, 77 broodstock and water samples from 14 ponds were investigated. Samples were collected from outer body surface of fish as well as from artificially hatched eggs. Isolation and identification of the fungus was done on colonial and microscopic characters. In this study, 84.11% samples were positive for fungal growth and fungus species belonging to seven different genuses were identified. Tricophyton, Saprolegnia, Rhizopus, Penicillium, Mucor, Microsporum and Alternaria were among the dominant isolated fungal species. Among the isolated genera, Tricophyton was detected from 13% of the samples, while Alternaria had the least with 3.7%, unidentified fungi accounts for 12% and unidentified yeast were 18.7%. Based on the results, various pathogenic fungi species were identified from fish body, water and hatched eggs, hence are potential causes of mortality and decreased egg hatchability. In the light of this, appropriate egg and water disinfection methods are essential for hatchery management. Fishes in rearing facilities must be given proper health management monitoring to prevent outbreak of fungal disease.
Key words: African catfish, fungus, egg, isolation, identification.