| Summary |
Eight hundred twenty cases of aquatic animal speciments were collected for diagnosis and monitoring program from January to December 2004 in Taiwan.Diagnosis of bacterial and viral diseases were carried out utilizing the techniques of viral isolation, PCR methods, API kits and analysis of 16S rRNA gene. Analysis of case sources revealed that 82％ were from private fish farms, 6.2％ from local Livestock Diseases Control Centers and university, 6.9％ from quarantine bureaus and 4.7％ from research programs. The percentage distribution of species in collected specimens include 15.4％ of freshwater fish (mainly Percidae spp), 66％ of seawater fish (maninly Epinephlus spp, Cobia, Lutjanidae spp), 6.2％ of pet fish(mainly koi), 6.5％ of crustacean, 4.3％ of amphibians, 0.3％ of shellfish and others 1.3％ from the total cases. Out of 252 cases of bacterial infections, both Streptococcus iniae (37.3％) and Nocardia seriolae (9.1％) infection were commonly found in freshwater and seawater fish. Vibrio spp infection(9.9％) usually occurred in summer, whereas Photobacterium damselae subsp. piscicida (4.7％) did in winter. A total of 327 cases of viral infection were diagnosed, which is composed of Iridovirus infection (49％), Virus nervous necrosis virus infection (36.2％), mixed infecton of above both virus (13％), Lymphocystivirus infection (4 cases), Koi herpesvirus infection (5 cases), birnavirus-like virus infection in crab (2 cases).Besides, 8 cases of parasitic infection, 1 case of fungal infection and 6 cases of other disease contributed to the total cases. The above results showed the major viral diseases in cultured fish are caused by Iridovirus and Virus nervous necrosis virus and the major bacterial diseases are caused by Streptococcus iniae, Nocardis seriolae, Vibrio spp infection. The above data of disease prevalence can provide reference for vaccine development and prevention policy, also resolving diseases problem for fish farmers.
|