Author
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JENKINS, MARK - 1265-40-00 |
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Submitted to: Review Article
Publication Type: Review Article Publication Acceptance Date: 12/8/2004 Publication Date: 1/22/2005 Citation: Jenkins, M. 2005. Present and future control of cryptosporidiosis in humans and animals. Review Article. Expert Review of Vaccines 3:669-671. Interpretive Summary: Cryptosporidiosis is an intestinal disease of humans and animals caused by the protozoan parasite Cryptosporidium parvum. The disease is prevalent in the young because of an incompletely developed immune system. Vaccination against cryptosporidiosis seeks to produce hyperimmune bovine colostrum (HBC) containing antibodies against surface proteins of the parasite. This colostrum can then be used to prophylactically treat newborn calves against C. parvum infection. While limited success has been achieved with complex mixture of proteins from C. parvum, this approach is not practical because it requires producing and purifying large numbers of parasites for incorporation into a vaccine. DNA cloning techniques have been used to generate large amounts of single recombinant proteins of C. parvum, which have been used to produce HBC against surface and internal C. parvum proteins. This HBC has shown efficacy in alleviating clinical signs of cryptosporidiosis after experimental challenge infection. These findings are now being tested under field conditions to determine if HBC against specific C. parvum proteins can passively protect calves naturally exposed to the parasite Technical Abstract: Although water treatment processes to remove Cryptosporidium are improving and detection methods for identifying the parasite in water are becoming more sensitive, outbreaks of cryptosporidiosis continue in the human population. Animals, especially dairy calves, often become infected because C. parvum oocysts are present in high numbers and remain viable for long periods of time after excretion, and no disinfectants or prophylactic or therapeutic reagents exist. Vaccination against C. parvum is being attempted in ruminants for the purpose of generating hyperimmune colostrum containing antibodies that may be effective in passive immunotherapy against cryptosporidiosis in the young. A number of recombinant C. parvum surface or internal antigens have been expressed by DNA cloning technology. Immune colostrum specific for several recombinant C. parvum proteins have shown efficacy in mouse and ruminant models against cryptosporidiosis. The P23 and CP15 antigens appear to be the most promising candidates for vaccine development. Recent studies have shown efficacy of the drug nitazoxanide against C. parvum infection in humans. In the near future, control of this parasitic disease in humans and animals will rely on a combination of passive immunotherapy and selective drug treatment. |
