Prevalence and genotypic diversity of ostreid herpesvirus type 1 in Crassostrea gigas cultured in the Gulf of California, Mexico

Abstract

In bivalve mollusk aquaculture, massive disease outbreaks with high mortality and large economic losses can occur, as in northwest Mexico in the 1990s. A range of pathogens can affect bivalves; one of great concern is ostreid herpesvirus 1 (OsHV-1), of which there are several strains. This virus has been detected in the Gulf of California in occasional or sporadic samplings, but to date, there have been few systematic studies. Monthly samples of Crassostrea gigas, water, and sediment were taken in the La Cruz coastal lagoon and analyzed by PCR. The native mollusk, Dosinia ponderosa, which lives outside the lagoon, was sampled as a control. The virus was found throughout the year only in C. gigas, with prevalence up to 60%. In total, 9 genotype variants were detected, and genetic analysis suggests that linear genotypic evolution has occurred from strain JF894308, present in La Cruz in 2011. There has been no evidence of the entry of new viral genotypes in the recent past, thus confinement of the virus within the lagoons of the Gulf of California could promote a native genotypic diversity in the short term.

Ostreid herpesvirus 1 latent infection and reactivation in adult Pacific oysters, Crassostrea gigas

“…These results suggest that OsHV-1 can become latent in the infected oysters. In agreement with our finding, the persistence of OsHV-1 after mortality events has been reported in other locations; for example, OsHV-1 was found in survivors from OsHV-1 mortality events in La Cruz lagoon, Mexico; Marennes-Oléron Bay, France; and Woolooware Bay, Australia ( Evans et al., 2017 ; Lionel et al., 2013 ; Martinez-Garcia et al., 2020 ).…”

The Resistance to Lethal Challenge with Ostreid herpesvirus-1 of Pacific Oysters (Crassostrea gigas) Previously Exposed to This Virus

“…OsHV-1 infection has been found in survivors after disease outbreaks at other locations in the world, for example in France [ 62 ], Mexico [ 63 ] and California [ 64 ]. This may be a consistent phenomenon leading to the development of natural resistance at the population level.…”

Tropical and Subtropical Ostreidae of the American Pacific: Taxonomy, Biology, Ecology, and Genetics

“…The OsHV-1 herpesvirus was later found in the gills of the species (V´asquez-Yeomans et al 2010). Recently, nine genotype variants of OsHV-1 were identified in the Gulf of California, and genetic analysis suggested that linear genotypic evolution had occurred from strain JF894308 present in lagoon La Cruz (Sonora, Mexico) in 2011 (Mart´ınez- Garc´ıa et al 2020). The prevalent pathogen of oysters, Perkinsus marinus, causing the dermo disease or perkinsosis, has been associated with massive mortalites of C. gigas in culture conditions along Sonoran coasts, Mexico .…”