Prevalence of infectious hypodermal and hematopoietic necrosis virus (IHHNV) in wild adult blue shrimp Penaeus stylirostris from the Northern Gulf ofCalifornia, Mexico

Conventional histopathology and molecular methods, including dot blot hybri dization with a specific DNA probe and polymerase chain reaction (PCR), wer e used to assess the prevalence and degree of severity of infectious hypode rmal and hematopoietic necrosis virus (IHHNV) infection in wild adult blue shrimp Penaeus stylirostris captured in the Northern Gulf of California. Th rough histopathological analysis, a presumptive diagnosis of IHHNV was init ially determined by demonstrating the presence of Cowdry type A inclusion b odies. Prevalence rate ranged from 80% to 100% in females and was 60% in ma les. Using the dot blot technique, the results showed that the presence of IHHNV varied in females from 86% to 89% and in males from 56% to 57%. Resul ts were further validated using PCR to assess the prevalence of IHHNV in eg gs and sperm. The PCR results showed that IHHNV prevalence in unfertilized eggs was 100% and in sperm was 60%. We concluded that wild adults of P. sty lirostris are infected with IHHNV but that they do not show clinical signs of disease. Our data suggest that in the 10th year of the IHHNV epizootic i n the Gulf of California, a host-pathogen relationship might have reached a putative equilibrium.