Disease in Tamil Nadu shrimps traced to Chinese live feed

Scientists say the recent outbreak of microsporidian infection that caused stunted growth in local shrimp varieties may have originated from the live feed imported from China, that is extensively used in shrimp farms. 

The Enterocytozoon hepatopenaei (EHP) parasite was identified last year as shrimp farmers witnessed stunted growth in the shrimps, which caused concern as this affected the size and market value of shrimp. 

This issue was discussed at a day-long workshop conducted by the Central Institute of Brackishwater Aquaculture (CIBA), where experts created awareness and chalked strategies to contain the disease caused by EHP. 

“EHP doesn’t kill the shrimp immediately like the white spot syndrome virus, which can wipe out entire hatcheries within days. The EHP affects the Indian-cultivated shrimp (Penaeus vannamei) as well as tiger shrimps, infecting the hepatopancreas and limiting the amount of nutrition received. As a result, the shrimps are starved and there is growth retardation,” said VS Chandrasekaran, Principal Scientist, CIBA, adding that the diseased shrimp doesn’t pose a risk to humans. “The process of cooking renders the shrimp safe. This disease affects the production on a commercial level and can lead to financial losses,” the scientist said. 

Dr Chandrasekharan pointed out that this disease may have originated due to the live feed used in shrimp farms. “This microsporidian disease is common in South East Asian countries like China, Thailand, Malaysia, Vietnam as well as countries like Mexico. So it is more likely to be present in India as well. We believe that the infection has occurred through the live feed, imported from China,” he said. 

Dr Chandrasekharan added that the infection can be contained, though chances of complete elimination are slim. “The Enterocytozoon hepatopenaei (EHP) is not a virus or bacteria. It cannot be treated by the usual medication as the drugs available are target specific. At the hatchery, good bio security will help reduce the instance of infection to young hatchlings. In the pond, hygiene of the environment and the workers should be followed as per the best practices specified by CIBA to reduce risk of infection,” he concluded.