Field efficacy of a novel porcine reproductive and respiratory syndrome modified-live virus vaccine with an emphasis on growth performance.

Background: This field evaluation was designed to evaluate the efficacy of a new porcine reproductive and respiratory syndrome virus-2 (PRRSV-2) modified live virus vaccine at three independent pig farms.

Methods: Three farms were selected for this study based on their respiratory disease status caused by PRRSV-2 infection in post-weaning and growing pigs. Each farm housed a total of 40, 18-day-old pigs that were randomly allocated to one of two treatment groups.

Evaluation of Formalin-Inactivated Vaccine Efficacy against Red Seabream Iridovirus (RSIV) in Laboratory and Field Conditions.

Red seabream iridovirus (RSIV) is a major cause of marine fish mortality in Korea, with no effective vaccine available since its first occurrence in the 1990s. This study evaluated the efficacy of a formalin-killed vaccine against RSIV in rock bream under laboratory and field conditions. For the field trial, a total of 103,200 rock bream from two commercial marine cage-cultured farms in Southern Korea were vaccinated.

Development of a high-dose vaccine formulation for prevention of megalocytivirus infection in rock bream (Oplegnathus fasciatus).

A formalin-inactivated red sea bream iridovirus (RSIV) vaccine was prepared using the culture supernatant of a persistently infected Pagrus major fin cell line (PI-PMF) with IVS-1 strain (RSIV subtype II Meglaocytivirus). Rock bream (Oplegnathus fasciatus) were injected with a high-dose, ultracentrifuged megalocytivirus vaccine (Ultra HSCMV, 7.0 × 10 copies/mL), a high-dose supernatant of cultured megalocytivirus vaccine (HSCMV, 1.

Development and characterization of megalocytivirus persistently-infected cell cultures for high yield of virus.

Megalocytivirus infection is a major threat in rock bream aquaculture in Korea. To produce a highly concentrated megalocytivirus, primary cells, established cell line and persistently infected cell line were used in this study. Megalocytivirus was inoculated in primary fin cell cultures of red sea bream (Pagrus major), rock bream (Oplegnathus fasciatus), olive flounder (Paralichthys olivaceus) and black sea bream (Acanthopagrus schlegelii) and produced at similar concentrations of 10 viral particles/mL in all cultures while produced 10 viral particles/mL in grunt fin (GF) cell line.

Complete genome sequence and pathogenic analysis of a new betanodavirus isolated from shellfish.

We determined the complete genomic RNA sequence of a new type of betanodavirus Korea shellfish nervous necrosis virus (KSNNV) isolated from shellfish. Compared with other isolates representing four genotypes of betanodaviruses, the identity of the whole nucleotide sequence of the virus was in the range of 76%-83% with the presence of specific genetic motifs and formed a separate new branch in the phylogenetic analysis. In pathogenic analysis by immersion method, KSNNV-KOR1 shows 100% cumulative mortality like SFRG10/2012BGGa1 (RGNNV) in newly hatched sevenband grouper and mandarin fish, which is clearly different from those found in negative control groups.

Evaluation of blue mussel Mytilus edulis as vector for viral hemorrhagic septicemia virus (VHSV).

When viral diseases occur in aquaculture farms, the virus released into the seawater from infected animals can re-infect other susceptible species or accumulate in filter-feeding organisms. We conducted a viral hemorrhagic septicemia virus (VHSV) survivability analysis of blue mussel Mytilus edulis digestive enzymes, viral depuration, and infectivity tests via in vitro and in vivo inoculation to evaluate the infectious state. VHSV particles were not completely digested within 24 h in vitro and were maintained for 7 d in the mussel digestive gland.