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Abstract
A total of 1096 cases of viral examination from 333 sampling were done on 54 farms in the aquaculture industry for export in 2006.The surveyed aquatic animals included grouper, cobia, koi, tropical fish, penaeid shrimp and abalone.
In shrimp diseases, the proportions of main disease were 33% for infectious hypodermal and haematopoietic necrosis (IHHN) and 15% for Taura syndrome (TS).Compared to results in the previous two years, White Spot Syndrome (WSS), Monodon Baculovirus Disease, Yellowhead Disease and Mourilyan Virus Disease were not found this year.
In marine fish diseases, the proportions for main diseases were 35% for nodavirus infection and 15% for grouper iridovirus infection.This revealed both diseases are still the main threat to the marine cultured fish.It is noted that the prevalence of nodavirus in grouper larvae and small juveniles was up to 83%.The result suggested that nodavirus infection spread out widely in grouper hatcheries in Taiwan.In mollusk diseases, the abalone was free from seven protozoan infections listed in OIE aquatic manual.
In freshwater fish diseases, we have not detected the pathogens of spring viremia of carp, infectious heamatopoietic necrosis, viral haematopoietic necrosis and epizootic haematopoietic necrosis in the tropical fish.In koi carp, the positive rate for koi herpesvirus (KHV) (7%) was higher than that (1%) in 2005.Due to KHV still sporadically-occurring in Taiwan, it is suggested that the potential reservoirs should be eradicated through extensive surveillance on more koi carp farms.In addition, farmers should receive more continuous educations to realize that the stamping-out policy is only way to solve this disease.Otherwise, KHV will preserve as the latent carriers in the field.Finally, there is no evidence showing any exotic aquatic diseases invading Taiwan.
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Abstract
The purpose of this surveillance was to realize epidemiology of avian influenza in Taiwan wild birds and poultry. In 2006, a total of 4,541 samples from wild birds (most of them were fecal samples) were examined. Thirty-nine viruses were isolated and subtyped as H1N3(n=2), H3N8(n=3), H4N6(n=17), H4N7(n=1), H7N3(n=1), H9N6(n=1), H9N9(n=1), H10N3(n=11)and H10N4(n=2).
Most of these viruses were isolated from duck fecal samples; but two viruses, H3N8 and H10N3, were isolated from terns. Only one low pathogenic strain of H7N3 virus was isolated from the wild ducks in Chayi of Taiwan. In the conclusion, Taiwan is still a H5N1-free country. There was no evidence of H5N1 virus carried by the entry migratory birds. So that, the invasion risk of this virus into Taiwan by migratory birds is very low.
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