IHHN Virus as an Etiological Factor in Runt‐Deformity Syndrome (RDS) of Juvenile Penaeus vannamei Cultured in Hawaii

Abstract

Runtdeformity syndrome (RDS) is an economically significant, frequent disease problem of cultured Penaeus vannamei. RDS is characterized by variable, often greatly reduced, growth rate of up to 30% of a cultured population and many shrimp with cuticle deformities of the rostrum, anterior appendages or other parts. The cause of RDS is undetermined.Nursery trials comparing histologically IHHN‐positive and histologically IHHN‐negative Penaeus vannamei cultured under identical conditions were conducted at The Oceanic Institute. The IHHN‐positive populations developed RDS symptoms including increased individual size variation, reduced population growth, and high prevalance of rostrum, antennae or cuticle deformity, while the IHHN‐negative groups displayed none of these symptoms. No other diseases or parasites were identified in the IHHN‐positive populations that would account for the RDS symptoms.A single commercialele nursery was stocked with histologidly IHHN‐positive P. vannamei and a high prevalence of RDS was observed. Shrimp growth was bimodal with a subpopulation growing normally and a subpopulation growing slowly. Significant relationships between shrimp harvest size and IHHN prevalance, selected individual organ IHHN severity grades and IHHN severity index (six organs evaluated) were found. Large, apparently normal shrimp were less severely infected with virus and did not display any cuticle deformities.In sum, these data provide epidemiological and histopathological evidence for the hypothesis that infection by IHHN virus is the cause of RDS in cultured P. vannamei.

Association of dual viral infection with mortality of Pacific white shrimp (Litopenaeus vannamei) in culture ponds in India

“…Except P. stylirostris, this virus has not been reported to be responsible for severe mortality in other penaeid shrimps. However, poor growth, slow mortality and external deformity caused by IHHNV in different shrimps have been reported [2,8].…”

Genomics, Molecular Epidemiology and Diagnostics of Infectious hypodermal and hematopoietic necrosis virus

“…The infected juvenile of P. vannamei and P. monodon show runt-deformity syndrome [11,13,16,34,66] whereas acute epidemics cause heavy mortalities in juveniles and sub-adults of P. stylirostris [6]. Like all other parvoviruses, IHHNV do not encode a DNA polymerase and depend on host cells for DNA replication and multiplication.…”

“…IHHNV infection has been demonstrated in all life stages of penaeid species including eggs, larvae, postlarvae (PL), juveniles and adults [3]. PL and juvenile shrimps are more susceptible to IHHNV infection than adults due to the presence of actively dividing cells [7,34,42]. IHHNVinfected females fail to develop embryos and also fail to hatch the eggs [3,59].…”

“…In P. vannamei, IHHN is typically a chronic disease [50] and the infection results in development and growth abnormalities known as runt deformity syndrome (RDS), [6,14,15,34,66]. Typical signs of RDS include deformed rostrum, wrinkled antennal flagella, cuticular roughness, 'bubbleheads' and deformation of 6th abdominal segment and tail fan.…”

“…IHHNV infection caused severe mortalities up to 90 % during 1981 in cultured P. (Litopenaeus) stylirostris postlarvae and juveniles in Hawaii, which were imported from commercial hatcheries in Costa Rica and Ecuador [41,50,51]. It has been reported to cause Runt deformity syndrome (RDS) in P. (Litopenaeus) vannamei [34] and P. monodon which is a chronic, non-lethal disease [51,66]. In this review, we discuss the recent progress on IHHNV, a major viral pathogen of penaeid shrimps worldwide.…”