Experimental susceptibility of Macrobrachium rosenbergii (de Man) subadults and adults to infectious myonecrosis virus (IMNV)

Infectious myonecrosis virus (IMNV) is considered one of the pathogens that most affect the production of Penaeus vannamei, causing economic losses estimated at billions of dollars. P. vannamei rearing is expanding to inland waters, which are commonly used for the farming of Macrobrachium rosenbergii, increasing the probability of exposure of this freshwater prawn to viruses often reported in penaeids, including IMNV. Therefore, the aim of the present study was to investigate the susceptibility of M. rosenbergii to IMNV through an intramuscular challenge. M. rosenbergii subadults and adults were inoculated intramuscularly with IMNV obtained from the abdominal muscle tissue of naturally infected P. vannamei. The viral challenge lasted 21 days. All samples had positive nested-PCR results as well as clinical signs and histopathological findings typical of the virus, such as hemocyte infiltration and muscle sinus dilation. This is the first study to demonstrate the susceptibility of M. rosenbergii subadults and adults to IMNV. Although no massive mortalities were detected in the challenged prawns, the presence of M. rosenbergii as a viral source in the cultivation environment should not be underestimated.