Teunis Peter F M, Chappell Cynthia L, Okhuysen Pablo C
National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
Risk Anal. 2002 Feb;22(1):175-83. doi: 10.1111/0272-4332.00014.
The infectivity of three different isolates of the waterborne protozoan parasite Cryptosporidium parvum has been tested in human feeding studies. These three isolates (Iowa, TAMU, and UCP) have different ID50s, indicating substantial variation in their infectivity for humans. This finding is of great importance for quantitative risk assessment as it provides strong evidence for heterogeneity in infectivity among isolates of the same species.
在人体喂养研究中测试了水源性原生动物寄生虫微小隐孢子虫三种不同分离株的感染性。这三种分离株（爱荷华株、德克萨斯农工大学株和加州大学河滨分校株）具有不同的半数感染剂量（ID50），表明它们对人类的感染性存在显著差异。这一发现对于定量风险评估非常重要，因为它为同一物种分离株之间感染性的异质性提供了有力证据。
