Named for the characteristic yellowish discoloration of the head, Yellow-head virus typically occurs in larger juveniles of giant tiger shrimp. Symptoms include sudden food consumption, followed by fasting and eventual death, often of the entire pond. Survivors are believed to become lifelong carriers. Although the method by which the disease is communicated in wild populations is unclear, managers of hatcheries consider wild stock to be a likely form of introduction of the Yellow-head Virus. The disease is thought to spread by means of contaminated water, decomposing fecal matter or tissue, cannibalism and fluid from diseased females.
Direct transmission can occur between unrelated crustacean species.
Humans may also facilitate transmission of the disease by global transportation of viable viruses in infected frozen imported shrimp. Experimental tests have shown that the Yellow-head Disease has caused serious damage to each important aquaculture species of the Gulf and American Pacific culture. The disease is thought to be caused by a baculovirus and affects shrimp of differing sizes. It occurs, most typically, in juvenile shrimp, but sometimes manifests itself in later adult stages. Symptoms include shell spotting and occasionally a reddish discoloration.