Ciliate Disease of Penaeid Shrimp


Category 3 (Host Not in Canada)

Common, generally accepted names of the organism or disease agent

Ciliate disease of shrimp.

Scientific name or taxonomic affiliation

a) Holotrich ciliate protozoan Paranophrys sp.
b) Holotrich, scuticociliate parasite Parauronema sp.

Geographic distribution

a) China.
b) Commercial shrimp hatchery in Gulf of Mexico region of the United States.

Host species

a) Cultured Penaeus chinensis (closely related species infect crabs and lobsters).
b) Cultured juvenile Penaeus aztecus.

Impact on the host

a) Early stages of infection are confined to wounds. Later stages invade the haemolymph and damage various organs including the gills. Disease is found in larvae and overwintering adults and often causes 100% mortality in infected tanks.

b) Ciliates in haemolymph causes mechanical injury by replacing and dislodging tissues and may become numerous enough to fill entire haemocoel and abdomen. Cilate believed to be an opportunistic invader that probably contributed to pathogenesis and mass mortality of cultured juvenile shrimp in conjunction with other pathogenic microorganisms (i.e., Baculovirus and a flagellate believed to be a species of Leptomonas (Sacromastigophora, Trypanosomatidae)).

Diagnostic techniques

Gross Observations: Haemolymph becomes turbid and does not clot.

Wet mount: Numerous ciliates and reduced haemocyte numbers in haemolymph.

Methods of control

No known treatment. Disease can be prevented by avoiding damage to shrimp, removal of diseased and dead shrimp, and washing live animal feeds with fresh water. Tanks and other equipment should be disinfected prior to use.


Chen, D. 1992. An overview of the disease situation, diagnostic techniques, treatments and preventives used on shrimp farms in China. In: W. Fulks and K.L. Main (eds.). Diseases of cultured penaeid shrimp in Asia and the United States. The Oceanic Institute, Honolulu, p. 47-55.

Couch J.A. 1978. Diseases, parasites and toxic responses of commercial penaeid shrimps of the Gulf of Mexico and south Atlantic coasts of North America. Fishery Bulletin 76: 1­44.

Citation Information

Bower, S.M. (1996): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Ciliate Disease of Penaeid Shrimp.

Date last revised: September 1996
Comments to Susan Bower

Date modified: