First Report of Dual Infection of Hepatopancreatic Parvovirus and Enterocytozoon hepatopenaei in Wild and Farmed Macrobrachium rosenbergii.

The freshwater prawn Macrobrachium rosenbergii is widely farmed in India, and except for Macrobrachium nodavirus (MrNV), no significant pathogens infecting this species have been reported. In this perspective, a histology- and PCR-based screening of M. rosenbergii was carried out for pathogens such as hepatopancreatic parvovirus (HPV), Enterocytozoon hepatopenaei (EHP) and infectious hypodermal and haematopoietic necrosis virus (IHHNV). For this, 335 samples were collected from five locations in Kerala, Maharashtra and West Bengal, India. Fifty animals, consisting of post-larvae, sub-adults and adults, were subjected to histological analysis, and the majority of the post-larvae (from Kerala) and a few sub-adult samples (from West Bengal) showed eosinophilic to basophilic, intranuclear inclusions, typical of HPV infection. The prevalence of HPV and EHP was found to be 61.3% and 95.4%, respectively, and 56.8% of the samples displayed multiple infections. None of the samples showed the presence of IHHNV. The sequence analysis of PCR amplicons indicated 90%-93% and 100% similarity to the capsid protein gene of HPV and the spore wall protein gene of EHP, respectively. This report formed the first documentation of HPV and EHP in M. rosenbergii from India and the first report of dual infections of these pathogens in freshwater prawn.