Scanning electron microscopy of the coccidian parasite Cryptosporidium sp. from cichlic fishes

Abstract

A scanning electron microscopic study of Cryp-tosporid~um sp. from the stomach of the cichlid fish Oreo-chromis aurea from Lake Kinnereth, Israel, revealed the exist-ence of regularly spaced prolections on their parasitophorous envelope. In young specimens the envelope was not complete leaving a hollow at their apex. Landsberg & Paperna (1986) authored a transmission electron microscopic (TEM) study of the coccidian Cryptospondium sp. which they found attached to the microvillar zone of the stomach epithelium of cultured hybrids of the cichlids Oreochromis aureus X 0. niloticus. Subsequently, Cryptosporidium sp. infection was found in fry (10 to 17 mm long) of 0. aureus collected from shallow pools fringing the northwestern shores of Lake I n n e r e t h , Israel. Isolated infected stomachs from 2 fish were processed for scanning elec-tron microscopy (SEM): fixed in Karnowski's fixative for 24 h at 4 "C, rinsed 3 times in cacodylate buffer (0.1 M, pH 7.4), dehydrated in an ascending series of alcohols, gradually infiltrated with amyl-acetate, criti-cal-point-dried from liquid carbon dioxide in a polaron E 3000, and sputter-coated with gold in a polaron E 5150. Specimens were examined and photographed using a Jeol JSM 35C SEM. Results are presented in Figs.