Abstract
Clinico-pathological and parasitological studies have been performed on spontaneous and experimental coccidiosis in guinea pigs. Among 11, 244 Hartley guinea pigs purchased from suppliers during 1968, 410 (3.6 %) of the animals had diarrhea due to coccidiosis. The incidence rate was high in the spring and fall with a mortality rate of 14.4 per cent. A particularly high number of fatal cases were found in the spring. In experimentally induced coccidiosis, clinical signs observed were diarrhea, dehydration, weight loss and death. The diarrhea developed in all animals on the eleventh day after infection and continued for one to five days. Food and water intakes were markedly reduced after the appearance of diarrhea, followed by anorexia and dehydration. Correlating with the appearance of diarrhea was a striking drop in body weight of the guinea pigs. Death usually occurred on the third to fifth day after the onset of diarrhea. The mortality rate was 30 per cent. The major macroscopic findings were characterized by a markedly thickened wall from the ascending to the descending colon and gelatinous edema of the mesenterium of the spiral of the ascending colon. Histologically, there was marked hyperplasia of the mucosal epithelium in the colon and numerous coccidia at different stages of development within the mucus membrane. In the advanced stages of the disease, there was degeneration and desquamation of the epithelia, marked edematous change and infiltration of neutrophil leukocytes and lymphocytes into the lamina propria and submucosa, many oocysts in the lumen of the intestine and in the intestinal glands. The oocysts were ellipsoidal or subspherical in shape with no micropile and measured 20 by 17μm. The sporulation time of the oocysts was two to three days. The prepatent period was eleven days after infection. The coccidia in the guinea pigs were identified as Eimeria caviae.
