Molecular surveillance of Cryptosporidium spp. in raw wastewater in Milwaukee: implications for understanding
Ling Zhou1, Ajaib Singh, Jianlin Jiang
1Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
Abstract:
Six Cryptosporidium spp. were found in 50 of 179 Milwaukee wastewater samples collected weekly over a year. Of the eight subtypes of Cryptosporidium hominis and Cryptosporidium parvum present, allele Ib was found in 14 of 16 samples, and its sequence was identical to that of the subtype in human samples from the 1993 Milwaukee outbreak of cryptosporidiosis.
Insights
Milwaukee wastewater contained six Cryptosporidium species, with a specific subtype (allele Ib) matching that from a 1993 human outbreak. This finding highlights potential sources of Cryptosporidium infection in the community.
Area of Science:
- Environmental microbiology
- Parasitology
- Public health
Background:
- Cryptosporidium is a significant cause of waterborne illness.
- Understanding Cryptosporidium transmission in urban environments is crucial for public health.
- Previous outbreaks in Milwaukee underscore the need for ongoing surveillance.
Purpose of the Study:
- To identify Cryptosporidium species and subtypes in Milwaukee wastewater.
- To investigate the genetic relationship between wastewater Cryptosporidium and human isolates.
- To assess the potential for wastewater as a reservoir for Cryptosporidium transmission.
Main Methods:
- Weekly collection of 179 wastewater samples over one year.
- Molecular detection and subtyping of Cryptosporidium species (hominis and parvum).
- Sequence analysis of identified subtypes and comparison with historical outbreak data.
Main Results:
- Six Cryptosporidium species were detected in 50 of 179 samples.
- Eight subtypes of C. hominis and C. parvum were identified.
- Allele Ib was prevalent, found in 14 of 16 samples, and genetically matched the 1993 outbreak subtype.
Conclusions:
- Milwaukee wastewater harbors diverse Cryptosporidium species and subtypes.
- The presence of the 1993 outbreak subtype in wastewater suggests ongoing transmission or a persistent environmental reservoir.
- Wastewater surveillance is a valuable tool for monitoring Cryptosporidium and assessing public health risks.
