Therapeutic efficacy of hyperimmune bovine colostrum treatment against clinical and subclinical Cryptosporidium serpentis infections in captive snakes.

Therapy based on the protective passive immunity of Hyperimmune Bovine Colostrum (HBC) (raised against Cryptosporidium parvum in dairy cows immunized during gestation) was tested for heterologous efficacy in subclinical and clinical infections of 12 captive snakes with C. serpentis. Six gastric HBC treatments of 1% snake weight at 1-week intervals each, have histologically cleared C. serpentis in three subclinically infected snakes, and regressed gastric histopathological changes in one of these snakes. In all snakes, each subsequent HBC treatment significantly decreased the number of oocysts recovered in gastric lavage eluants (P < 0.03). The treatments induced oocyst-negative gastric eluants and stools in all snakes, and improved clinical signs of infection. Clinically infected snakes displayed severe histopathological changes in the gastric region; however, the numbers of developmental stages of C. serpentis were moderate. Considering the severity of pathology, much lower than expected pathogen numbers were observed, and it is believed that clinically infected snakes did not have enough time to repair tissue damage that had occurred over the years of infection. As the HBC treatment was safe and highly efficacious, it is recommended to gastrically administer the HBC therapeutically to snakes that are clinically or subclinically infected with C. serpentis. Hyperimmune bovine colostrum can also be used in snake supportive therapy or prophylaxis.