Yellowhead disease (YHD) is a viral infection of shrimp and prawn , in particular of the giant tiger prawn ( Penaeus monodon ), one of the major species of farmed shrimp . The disease is highly lethal and contagious, killing shrimp quickly. Outbreaks of this disease have been reported in P. monodon , ie, particularly Southeast Asian 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 coronaviruses and arteriviruses . A closely related virus is the gill-associated virus(GAV), which is the type species of the Okavirus genus .
The cephalothorax of infected shrimp turns yellow after a period of unusually high feeding activity abruptly ending, and the moribund shrimps shrimps off the surface of their pond before dying. YHD leads to death of the animals within two to four days. 
YHD had been reported in Thailand in 1990, the closely related GAV has been discovered in 1995 during a yellowhead-like disease in Australian shrimp farms.
- Jump up^ Gulf States Marine Fisheries Commission: Non-Native Species Summaries: Yellowhead Virus (YHV) , 2003. Accessed June 30, 2005.
- Jump up^ World Organization for Animal Health(OIE):Aquatic Manual, 4th Ed., 2003.Section 4.1.3. ISBN 92-9044-563-7.