Yellowhead disease
Yellowhead disease (YHD) 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 Asian farms. In Thai, the disease is called hua leung.[1]
| Yellow head virus | |
|---|---|
Virus classification  | |
| (unranked): | Virus |
| Realm: | Riboviria |
| Phylum: | incertae sedis |
| Order: | Nidovirales |
| Family: | Roniviridae |
| Genus: | Okavirus |
| Subgenus: | Tipravirus |
| Species: | Yellow head virus |
The disease is caused by the Yellow head virus (YHV), a positive-sense single-stranded RNA virus related to coronaviruses and arteriviruses. A closely related virus is the Gill-associated virus (GAV), which is the type species of the genus Okavirus.
Clinical
The cephalothorax 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.[2]
History
YHD had been reported first from Thailand in 1990, the closely related GAV has been discovered in 1995 during a yellowhead-like disease in Australian shrimp farms.
References
- Gulf States Marine Fisheries Commission: Non-Native Species Summaries: Yellowhead Virus (YHV) Archived 2007-09-28 at the Wayback Machine, 2003. Accessed June 30, 2005.
- World Organization for Animal Health (OIE): Aquatic Manual, 4th Ed., 2003. Section 4.1.3 Archived 2005-04-03 at the Wayback Machine. ISBN 92-9044-563-7.