COUCH: DISEASES AND PARASITES OF PENAEID SHRIMPS 





Figure 16. — a. Thelohania penaei sporocysts and spores; note approximate size of sporocysts with eight spores each; dark bodies are 

 trophozoites or early sporonts. x 1 ,000. b. Thelohania penaei sporocysts, higher magnification; note that each sporocyst contains about 

 eight spores; dark body (arrow) is probably an early sporont or trophozoite of this species, x 1,500. 



(in Sprague 1970) first reported the genus Pleis- 

 tophora in penaeid shrimps (Penaeus aztecus and 

 P. setiferus from Louisiana). Constransitch (1970) 

 named the species from Louisiana Pleistophora 

 penaei. Tissues infected were tail muscle, cardiac 

 muscle, hepatopancreas, and intestinal and 

 stomach walls. Baxter et al. ( 1970) then reported a 

 similar species from the same hosts from Texas. 

 The Texas Pleistophora consisted of sporocysts 

 that contained 40 or more spores. 



Recently, Iversen and Kelly (1976) reported a 

 Pleistophora sp. from the pink shrimp for the first 

 time. 



Therapeutic Measures for Microsporidosis 



Very little work has been done on attempting to 



control or treat microsporidan infection in reared 

 shrimp. Quick removal of "cotton" or obviously 

 infected shrimp from tanks or ponds should aid in 

 preventing spread of infections. Overstreet (1975) 

 has reported some success in treating blue crabs 

 with the drug Buquinolate to prevent infection by 

 Nosema michaelis, a common microsporidan in 

 blue crabs. He fed the drug to crabs in food con- 

 taminated with A^. michaelis spores. He also fed 

 the drug in food without spores 48 h preceding or 

 following spore feeding. Control crabs were fed 

 spores, but no drug. Drug and spore-fed blue crabs 

 had significantly fewer infections develop than did 

 crabs fed spores only. Whether Buquinolate or 

 other drugs would be helpful in preventing mi- 

 crosporidosis in shrimp remains to be determined. 

 Even if a drug is useful in therapy of a disease in 



15 



