Protection of Calves Against Cryptosporidiosis by Hyperimmunization of Pregnant Cattle Colostrum using Oocyst Whole Antigens
2022
Mokhber Dezfouli, Mohamad Reza | Zarghami, Faisal | Rahbari, Sadegh | Ebrahimzadeh Abkooh, Elahe | Lotfollahzadeh, Samad | Sadeghian Chaleshtori, Sirous | Shayan, Parviz
BACKGROUND: Cryptosporidium parvum is a coccidian parasite with worldwide distribution. OBJECTIVES: It is considered one of the most important causes of diarrhea in many vertebrate species and im-munocompromised humans. Due to the lack of effective treatment of cryptosporidiosis, protection strategy against this species can be focused on encouraging the immune system through vaccine development. METHODS: For this aim, we prepared oocysts lysate as a whole antigen vaccine candidate (420 μg) and immun-ized 3 pregnant cows 4 times every 2 weeks from 70 days to parturition. As a control group, 3 unimmunized pregnant cows were used. After parturition, each calf was fed with colostrum of his dam and challenged at 12h of age with 1×107C. parvum oocysts. RESULTS: In contrast to the test group, the calves in the control group developed severe watery diarrhea with excretion of oocysts from 4 days post-infection. The calves in the test group, which received the hyperimmune colostrum, showed no clinical signs and a significant reduction in oocysts excretion. CONCLUSIONS: The whole antigen prepared from oocysts of C. parvum can be considered a suitable candidate for immunizing pregnant cows producing hyperimmune colostrum.
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