Yellowhead disease
Encyclopedia
Yellowhead disease is a viral
infection of shrimp
and prawn
, in particular of the giant tiger prawn
(Penaeus monodon), one of the two major species of farmed shrimp
. The disease is highly lethal and contagious, killing shrimp quickly. Outbreaks of this disease have wiped out in a matter of days the entire populations of many shrimp farms that cultivated P. monodon, i.e. particularly Southeast Asia
n farms. In Thai
, the disease is called Hua leung.
The disease is caused by the yellowhead virus (YHV), a positive-sense single-stranded RNA
virus related to coronavirus
es and arterivirus
es. A closely related virus is the gill-associated virus (GAV), which is the type species of the genus
Okavirus.
of infected shrimp turns yellow after a period of unusually high feeding activity ending abruptly, and the then moribund shrimps congregate near the surface of their pond before dying. YHD leads to death of the animals within two to four days.
in 1990, the closely related GAV has been discovered in 1995 during a yellowhead-like disease in Australia
n shrimp farms.
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
infection of shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
and prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
, in particular of the giant tiger prawn
Penaeus monodon
Penaeus monodon, the giant tiger prawn , is a marine crustacean that is widely reared for food.-Distribution:...
(Penaeus monodon), one of the two major species of farmed shrimp
Shrimp farm
A shrimp farm is an aquaculture business for the cultivation of marine shrimp or prawns for human consumption. Commercial shrimp farming began in the 1970s, and production grew steeply, particularly to match the market demands of the United States, Japan and Western Europe...
. The disease is highly lethal and contagious, killing shrimp quickly. Outbreaks of this disease have wiped out in a matter of days the entire populations of many shrimp farms that cultivated P. monodon, i.e. particularly Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
n farms. In Thai
Thai language
Thai , also known as Central Thai and Siamese, is the national and official language of Thailand and the native language of the Thai people, Thailand's dominant ethnic group. Thai is a member of the Tai group of the Tai–Kadai language family. Historical linguists have been unable to definitively...
, the disease is called Hua leung.
The disease is caused by the yellowhead virus (YHV), a positive-sense single-stranded RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
virus related to coronavirus
Coronavirus
Coronaviruses are species in the genera of virus belonging to the subfamily Coronavirinae in the family Coronaviridae. Coronaviruses are enveloped viruses with a positive-sense single-stranded RNA genome and a helical symmetry. The genomic size of coronaviruses ranges from approximately 16 to 31...
es and arterivirus
Arterivirus
Arterivirus is a genus of virus, with type species equine arteritis virus. In 1996, the family Arteriviridae was included within the order Nidovirales. Arteriviruses are small, enveloped, animal viruses with an icosahedral core containing a positive-sense RNA genome...
es. A closely related virus is the gill-associated virus (GAV), which is the type species of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Okavirus.
Clinical
The cephalothoraxCephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
of infected shrimp turns yellow after a period of unusually high feeding activity ending abruptly, and the then moribund shrimps congregate near the surface of their pond before dying. YHD leads to death of the animals within two to four days.
History
YHD had been reported first from ThailandThailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
in 1990, the closely related GAV has been discovered in 1995 during a yellowhead-like disease in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n shrimp farms.