Harp J A, Goff J P
U.S. Department of Agriculture, Agricultural Research Service, National Animal Disease Center, Ames, Iowa 50010.
J Parasitol. 1995 Feb;81(1):54-7.
Cryptosporidium parvum causes enteric infection and diarrhea in calves, other species of economically important livestock, and humans. There are no effective treatments currently licensed for this parasite, and preventive measures are difficult. In addition to direct economic losses to the cattle industry, infected calves may contaminate water supplies with oocysts and contribute to human cryptosporidiosis. We have developed a vaccine offering partial protection against C. parvum infection in calves. Nine calves received an oral preparation of lyophilized C. parvum oocysts shortly after birth, and 10 calves served as nonvaccinated controls. All calves received colostrum. At 1 wk of age, all calves were administered 10(4) viable C. parvum oocysts orally. Clinical disease and oocyst shedding were monitored daily. Mean duration of diarrhea was 4 days for control calves and 1.7 days for vaccinated calves. Mean duration of oocyst shedding was 5.3 days for control calves and 2 days for vaccinated calves. These differences were statistically significant and suggest that this vaccine has the potential to reduce diarrhea and oocyst shedding caused by C. parvum.
微小隐孢子虫可导致犊牛、其他具有重要经济价值的家畜品种以及人类发生肠道感染和腹泻。目前尚无针对这种寄生虫的有效许可治疗方法，预防措施也很困难。除了给养牛业造成直接经济损失外，受感染的犊牛可能会用卵囊污染水源，并导致人类隐孢子虫病。我们开发了一种疫苗，可对犊牛的微小隐孢子虫感染提供部分保护。9头犊牛在出生后不久接受了冻干微小隐孢子虫卵囊的口服制剂，10头犊牛作为未接种疫苗的对照。所有犊牛都接受了初乳。在1周龄时，所有犊牛口服接种10⁴个活的微小隐孢子虫卵囊。每天监测临床疾病和卵囊排出情况。对照犊牛腹泻的平均持续时间为4天，接种疫苗的犊牛为1.7天。对照犊牛卵囊排出的平均持续时间为5.3天，接种疫苗的犊牛为2天。这些差异具有统计学意义，表明这种疫苗有可能减少微小隐孢子虫引起的腹泻和卵囊排出。
