Pleistophora spa (Microsporidia: Nosematidae): a new parasite of shrimp

In a recent study of parasites in shrimp from Galveston Bay, Texas, 4 Penaeus setiferus and 4 P. aztecus were found infected with Pleistophora. This is the 1 st report of Pleistophora in shrimp. Shrimp infected with Pleistophora. appeared similar to those infected with Nosema. 'Cysts', developing stages of the parasite and spores are described and illustrated. No indication as to how the microsporidians were disseminated through the body of the shrimp was obtained. Pleistophora was observed to occur less frequently than Nosema nelsoni in shrimp from Galveston Bay, but both spp infect brown and white shrimp