Clinico-haematological studies on experimental Cryptosporidium parvum Jammu isolate infection in Swiss albino mice

The present study was conducted to determine the clinco-haematological effects of a well characterized Cryptosporidium parvum isolate in Swiss albino mice. Sixty female mice were divided into four groups. Group I mice served as healthy control. In group II, C. parvum oocysts were administered orally, mice of group III were given dexamethasone in drinking water whereas group IV mice were given dexamethasone along with C. parvum oocysts. Clinical signs were more severe in immunosuppressed infected mice and observed dullness, depression, inappetance, poor fur condition, progressive weakness, and decrease in body weight. In addition, mice in group IV showed profuse diarrhoea. An overall mortality rate of 7% and 20% was seen in group III and IV animals, respectively. Animals of group IV had significantly lower average body weight as compared to other groups around the time of peak infection with C. parvum which was recorded to be around 10^th DPI. Based on severity of clinical disease and oocyst shedding intensity significant leukocytosis along with neutrophilia and lymphocytopenia was observed in group IV mice at 10^th DPI as compared to mice in other groups. It was concluded that experimental infection with C. parvum in mice caused a severe clinical disease which peaked around 10^th day and was seen to subsequently resolve around 15 DPI.