Jareeporn Ruangsri, Suphada Kiriratnikom, Nopphadol Sukrakanchana, Supatra Arunrat, Nirut Sukasem, Thanawut Klowkliang, Jiraporn Kasornchandra, and Kitjakarn Supamattaya

pp. 215 - 224

Abstract

This study aimed to survey the prevalence of some infectious diseases e.g. Taura syndrome virus (TSV)
and Infectious hypodermal and haematopoietic necrosis virus (IHHNV) in white shrimp (Penaeus vannamei) populations and to assess the impact of such infectious agents to indigenous aquatic animals in Thailand.
Samples of both larval and juvenile or adult shrimp from each region of the country were collected and
screened for TSV and IHHNV using the polymerase chain reaction (PCR) technique. Viruses isolated from
affected shrimp were used for determine the susceptibility to infection of some aquatic species native to
Thailand.
A total of 163 samples of larval shrimp from hatcheries were screened. The results showed infection
with TSV and IHHNV in 3.68 and 44.17%, respectively. As high as 7.32% TSV infection was detected in
shrimp samples collected from the South Eastern coast, followed by the Eastern and Central regions with
percentages of 5.56 and 4.53, respectively. Shrimp with the highest rate of IHHNV infection, 55.56% were
collected from the Eastern region.
A total of 192 samples of shrimp reared in grow-out ponds were also collected. The results showed
shrimp were infected with TSV and IHHNV with percentages of 6.67 and 67.19, respectively. The highest
prevalence of IHHNV (up to 90%) was found in samples collected from the lower Southern region. The
highest prevalence of TSV infection (11.29%) was reported in shrimp from the Central region.
A study of the susceptibility to TSV and IHHNV infection of some indigenous aquatic species of
Thailand was also carried out. The results showed many aquatic species native to Thailand e.g. black tiger
shrimp (Penaeus monodon), speckled shrimp (Metapenaeus monoceros), dwarf prawn (Macrobrachium
equideus), krill (Acetes sp.), mantis lobster (Chloridopsis immaculatus), freshwater prawn (Macrobrachium
lanchesteri and M. rosenbergii), mangrove crab (Sesarma sp.) and mud crab (Scylla serrata) were susceptible
to viruses and died due to infection. The mortality of affected species associated with a causative agent was
confirmed in most species, except the mud crab and freshwater prawn (Marcrobrachium rosenbergii).
However, viral particles can be still detected in surviving animals 10 days after infection.
The results of this study will be a helpful tool employed in establishing measures on disease control
and reduction of risk with the importation of white shrimp broodstock.