Kvác Martin, Sak Bohumil, Kvetonová Dana, Secor W Evan
Department of Medical and Veterinary Parasitology, Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, v.v.i., Branisovská 31, 370 05 Ceské Budejovice, Czech Republic.
Vet Parasitol. 2009 Jul 7;163(1-2):33-8. doi: 10.1016/j.vetpar.2009.03.047. Epub 2009 Apr 5.
We exposed juvenile (7-day old) and adult (8-week old) Mongolian gerbils (Meriones unguiculatus) to Cryptosporidium andersoni or C. muris, which infect the stomach, or to C. parvum, which infects the intestine. Both age groups could be successfully infected with each species in primary mono-infection with juvenile animals demonstrating higher peak oocysts per gram of feces and longer patent periods than adults. Concurrent exposure to mixed gastric and intestinal cryptosporidia resulted in successful infection with both species. The time course and infection intensities in the mixed infections were similar to those of primary mono-infection and for a given species. Similarly, sequential mixed infection of C. andersoni positive gerbils with C. muris 25 days after exposure to C. andersoni resulted in simultaneous infection with both gastric species. In contrast, following primary infection and clearance, animals re-exposed to the same Cryptosporidium species, failed to excrete oocysts in their feces and histological examination revealed no developmental stages in the stomach or intestine. In cross-infections, where the secondary exposure was with a different Cryptosporidium species than the initial cleared infection, successful infection was possible with a gastric species following C. parvum, or with C. parvum following a gastric species, but primary infection with one gastric species precluded secondary infection with the other gastric species. These results indicate cross-immunity between gastric Cryptosporidium species but not between intestinal and gastric species. Furthermore, our study demonstrates that Mongolian gerbils are susceptible to infection with many Cryptosporidium species and are a useful laboratory model for studies of mixed cryptosporidiosis.
我们将幼年（7日龄）和成年（8周龄）蒙古沙鼠（长爪沙鼠）暴露于感染胃部的安氏隐孢子虫或鼠隐孢子虫，或感染肠道的微小隐孢子虫。在初次单一感染中，两个年龄组都能成功感染每种寄生虫，幼年动物每克粪便中的卵囊峰值更高，排虫期比成年动物更长。同时暴露于混合的胃部和肠道隐孢子虫会导致两种寄生虫都成功感染。混合感染中的时间进程和感染强度与初次单一感染中给定物种的情况相似。同样，在暴露于安氏隐孢子虫25天后，将安氏隐孢子虫阳性的沙鼠与鼠隐孢子虫进行序贯混合感染，会导致两种胃部寄生虫同时感染。相比之下，在初次感染并清除后，再次暴露于相同隐孢子虫物种的动物，粪便中未排出卵囊，组织学检查显示胃或肠道中没有发育阶段。在交叉感染中，二次暴露的隐孢子虫物种与最初清除的感染物种不同，在微小隐孢子虫感染后可能成功感染一种胃部寄生虫，或者在一种胃部寄生虫感染后成功感染微小隐孢子虫，但初次感染一种胃部寄生虫会阻止二次感染另一种胃部寄生虫。这些结果表明胃部隐孢子虫物种之间存在交叉免疫，但肠道和胃部物种之间不存在。此外，我们的研究表明蒙古沙鼠易受多种隐孢子虫物种的感染，是研究混合隐孢子虫病的有用实验室模型。
