Natural co-infection with infectious hypodermal and hematopoietic necrosis virus (IHHNV) and infectious myonecrosis virus (IMNV) in Litopenaeus vannamei in Brazil

Cultivation of whiteleg shrimp (Litopenaeus vannamei) constitutes a growing aquaculture industry in northeast Brazil. Similar to other animals that are intensively farmed, shrimp experience disease outbreaks, which are a constant threat and cause eventually significant economical losses. Infectious hypodermal and hematopoietic necrosis virus (IHHNV) and infectious myonecrosis virus (IMNV) are prevalent epizootic viral agents in Brazil. In a routine monitoring program for the diagnosis of IHHNV and IMNV, using molecular techniques like conventional PCR, reverse transcription coupled with PCR (RT-PCR) and absolute quantitative PCR (qPCR), we found that most positive samples of shrimp were simultaneously co-infected with both viruses. This survey is the first to show the occurrence of a natural co-infection that is caused by IHHNV and IMNV in penaeid shrimp attacked by viral disease that were cultivated in Northeast Brazil.