本文主要研究美国地下水供应中隐孢子虫和贾第虫的流行情况。对48个相邻州中23个州199个地点的463个地下水样本进行了隐孢子虫或贾第虫或两者的分析。地下水来源为垂直井、泉水、渗透廊道和水平井。使用免疫荧光技术分析样本。报告中说明了调查结果，包括按污染源类型细分的污染场所的百分比。包括12个参考文献和表格。

This article focuses on the prevalence of Cryptosporidium and Giardia in US groundwater supplies. 463 groundwater samples from 199 sites in 23 of the 48 contiguous states were analyzed for the appearance of Cryptosporidium or Giardia or both. The groundwater sources were vertical wells, springs, infiltration galleries, and horizontal wells. Samples were analyzed using an immunofluorescence technique. Results of the findings are stated, including the percentage of contaminated sites broken down by source type. Includes 12 references, tables.