Monodon slow growth syndrome of black tiger shrimp

A survey conducted by this Institute revealed that the economic loss due to shrimp diseases was estimated to be Rs.1022  crores   and that   due to slow growth syndrome  and white gut disease  was  Rs. 120 crores annually. One of the emerging diseases is the abnormal slow growth syndrome which exhibits marked size-differences among individuals with obscure etiology. This is an emerging disease in farmed black tiger shrimp in India.   Further investigations carried out during last year with 110 samples indicated that the symptoms of the affected shrimp fitted to the case definition of Monodon Slow Growth Syndrome (MSGS) as given by Thai research workers. The Laem-Singh Virus (LSNV) was also detected in 75.5 % of the   samples analyzed. During the current year, 85 samples were collected from Andhra Pradesh and Tamil Nadu and a detailed investigation was carried out using histopathology, electron microscopy and molecular diagnostic methods. Histopathological examination indicated characterstic  lesions such as haemocytic infiltration and enlargement of vessels in the eye-stalk, collectively termed as retinopathy  in  the  MSGS affected shrimp. Electron microscopy of tissues of selected suspected samples showed numerous naked virus-like particles (20 nm)