Center for Infectious Diseases, The University of Texas Health Science Center, Houston, TX, USA.
Am J Trop Med Hyg. 2011 Aug;85(2):238-42. doi: 10.4269/ajtmh.2011.10-0664.
Most Cryptosporidium infections in humans are caused by C. parvum or C. hominis. However, genotyping techniques have identified infections caused by unusual Cryptosporidium species. Cryptosporidium meleagridis has been identified in ≤ 1% of persons with diarrhea, although prevalence is higher in developing nations. We examined the infectivity of C. meleagridis in healthy adults. Five volunteers were challenged with 10(5) C. meleagridis oocysts and monitored six weeks for fecal oocysts and clinical manifestations. Four volunteers had diarrhea; three had detectable fecal oocysts; and one infected volunteer remained asymptomatic. Fecal DNA from two volunteers was amplified by using a polymerase chain reaction specific for the Cryptosporidium small subunit ribosomal RNA gene. Nucleotide sequence of these amplicons was diagnostic for C. meleagridis. All infections were self-limited; oocysts were cleared within ≤ 12 days of challenge. These studies establish that healthy adults can be infected and become ill from ingestion of C. meleagridis oocysts.
大多数人类隐孢子虫感染是由 C. parvum 或 C. hominis 引起的。然而，基因分型技术已经鉴定出由不常见的隐孢子虫物种引起的感染。虽然在发展中国家的患病率更高，但在腹泻患者中，仅鉴定出 ≤ 1%的人感染了 C. meleagridis。我们研究了 C. meleagridis 在健康成年人中的感染性。将 10(5)个 C. meleagridis 卵囊挑战给五名志愿者，并在接下来的六周内监测粪便卵囊和临床表现。四名志愿者出现腹泻；三名志愿者可检测到粪便卵囊；一名受感染的志愿者无症状。使用针对隐孢子虫小亚基核糖体 RNA 基因的聚合酶链反应从两名志愿者的粪便 DNA 中扩增。这些扩增子的核苷酸序列可诊断为 C. meleagridis。所有感染均自行限制；卵囊在挑战后 ≤ 12 天内清除。这些研究表明，健康成年人可以通过摄入 C. meleagridis 卵囊而感染并患病。
