Prevalence of Baculovirus penaei in experimentally infected white shrimp ( Penaeus vannamei) relative to age

Abstract

Age of Penaeus vannamei influences infections with Baculovirus penaei in different ways. The virus has less effect on host survival in the older of seven tested age-groups of shrimp experimentally administered virus; no virus-induced mortality occurred in postlarvae older than 63 days. Prevalence of newly acquired infections decreases as age increases, sometimes to zero. Prepatency periods appear to increase by a few days in infections in most successively older tested age-groups. Actual and relative numbers of affected hepatopancreatic cells decrease from 75 or 80% typically seen in postlarvae infected when 3 days old to ≤ 5% typically seen in infected individuals exposed when they were 63 to 157 days old; infections become undetectable in individuals exposed when they were 325 and 454 days old.