Pathomorphological studies on Cryptosporidium parvum infection in immunocompromised and immunocompetent Swiss albino mice

Abstract

The present study was conducted to determine the pathogenic potential of Cryptosporidium parvum, isolated froma naturally infected calfin Jammu, in immunocompetent and immunocompromised Swiss albino mice. The mice were divided into four groups. Group I (G-I) mice served as healthy control. Group II (G-II) received C. parvum oocysts orally; mice of Group III (G-III) were given dexamethasone intraperitoneally, whereas Group IV (G-IV) were administered dexamethasone along with C. parvum oocysts. The peak intensity of infection as determined by severity of clinical signs and oocyst shedding in feceswas observed on 10th day post infection (DPI). Pathological lesions were seen in liver and spleen of G-III and G-IV mice and intestines of G-II and G-IV mice. Liver of G-III and G-IV mice revealed moderate to severe congestion, fatty changes, multifocal necrosis and infiltration of numerous leukocytes mainly consisting of polymorphonuclear cells. These lesions were more severe in G-IV mice especially around peak infection period. In contrast to mild enteritis in G-II animals, severe necrotizing and haemorrhagic enteritis was seen in G-IV mice characterised by wide spread sloughing, stunting, bluntingand fusion of intestinal villi along with the infiltration of lymphocytes in lamina propria and submucosa of small intestine. The intensity of enteric disease was gradually subsided after 10th DPI and completely resolved in G-II and G-IV animals on 12th and 15th DPI, respectively. It was concluded that C. parvum caused a severe enteric infection in immunocompromised mice.