Effect of desiccation, pH, heat, and ultraviolet irradiation on viability of Baculovirus penaei

Abstract

Tolerance of Baculovirus penaei virus to desiccation, pH, heat, and ultraviolet irradiation (uv), as well as its survival in 32 ppt sea water, was investigated using larval Penaeus vannamei in a bioassay. Test shrimp were sampled from 36 to 264 hr after food-borne exposure to treated B. penaei and examined for patent infections (polyhedral inclusion bodies detectable in fresh preparations of hepatopancreas) with light microscopy. B. penaei was completely inactivated within 30 min after exposure to pH 3, whereas exposure to pH 11 extended the prepatency period (period before infection is apparent) but did not inactivate the virus. B. penaei was inactivated by 10-min exposures to temperatures of 60–90°C. Ultraviolet irradiation for 40 min at a wavelength of 254 nm when B. penaei was 5 cm from the light source inactivated the virus (measured as a cumulative uv dosage of 7.08 × 10 6 μW · sec/cm 2). Desiccation for 48 hr also inactivated the virus, and that method is the most practical to halt or prevent infections in some aquaculture facilities. B. penaei free from its host survived 32 ppt sea water at 22°C for 7 days and at 5°C for at least 14 days.