Widespread detection of Wenzhou shrimp virus 8 (WzSV8) and it's implication in cultured shrimp (Penaeus vannamei) farms of India.

Like in other parts of world, Indian shrimp aquaculture industry is also suffering from diseases and mortalities and many of the pathogens have invaded into India. Here, an attempt was made to investigate the presence of newly described shrimp virus, Wenzhou shrimp virus 8 (WzSV8). More than 200 shrimp samples from different locations of India were collected and analysed for the presence of this virus. Widespread detection of WzSV8 was observed in shrimp farms of India where 58% of samples were found to be positive for this virus. Many of the samples had only WzSV8 infection and in others co-infection with other shrimp pathogens such as WSSV, IMNV and EHP were observed. Presence of WzSV8 was confirmed through PCR, histopathology, in situ hybridization, transmission electron microscopy and transcriptomics. To find out target organs for the detection of WzSV8, hepatopancreas, gut, stomach, gill and muscle were processed by PCR. Only samples from HP, gut and stomach were positive for this virus and muscle and gill were negative. A strong correlation of WzSV8 with shrimp white gut syndrome (WGS) was observed where WGS samples always had high load of this virus. Phylogenetically the Indian isolates were closer to Chinese isolates. The role of this virus in causing disease directly or precipitating the pathological conditions through co-infection needs to be studied further. Particularly, analysing the role of WzSV8 in shrimp white gut syndrome may provide clues about the disease mechanism.