Detection of a nonoccluded baculovirus in penaeid shrimp by PCR

Specimen of Penaeus chznenszs were collected from hatchery ponds at Jimo, Qingdao before, during and after explosive epidemic disease respectively in July to September 1997.In order to establish rapid diagnosis techniques for shrimp explosive epidemic virus, diseased samples are detected by polymerase chain reaction(PCR).The primers which are synthesized according to the genome sequence of partially cloned shrimp baculovirus can specifically amplify the target baculoviral DNA, the viral DNA can be detected as low in quantity as 1 pg.The virus can be detected from the stomach, gill, hapatopancrease, min-gut, pereopod, muscle and heart of the penaeid shrimps with typical symptom of explosive epidemic disease.The positive signals vary strength from the strongest in stomach,the min-gut, muscle, heart and pereopod in the middle, to the weadest in gill and hapatopancrease.This result demon-strates the different numbers and affection extent of virus in different tissues or organs.Virus can also be detected by nested PCR during latent and convalescent periods from shrimps showing no obvious sympton of acute disease, whereas the results on healthy wild P.Chinensis are negative.With its sensitivity, accuracy and specificity, PCR is significant for the early diagnosis of viral disease and the high healthy stock brding of penaeid shrimp.