Genotype-Specific Detection of Measles Virus Using Wastewater Surveillance - Wisconsin, February 2026

Area of Science:

• Public Health
• Infectious Disease Surveillance
• Environmental Virology

Background:

• Measles remains a public health concern, necessitating robust surveillance methods.
• Wastewater surveillance offers a potential tool for early detection of infectious agents.
• Genomic diversity of measles virus requires adaptable detection methodologies.

Purpose of the Study:

• To evaluate the utility of wastewater surveillance for detecting single cases of measles.
• To assess the performance of a common measles wastewater surveillance assay against different genotypes.
• To highlight the importance of genomic data in monitoring and improving diagnostic assays.

Main Methods:

• Wastewater (sewage) surveillance was employed to detect wild-type measles virus.
• A standard measles wastewater surveillance assay was utilized and subsequently analyzed for performance.
• Alternative assays and whole-genome sequencing data were used to confirm findings and identify assay limitations.

Main Results:

• Wastewater surveillance detected measles virus from one travel-associated case prior to its clinical identification.
• The standard assay failed to detect measles genotype B3 variant, despite its presence in wastewater.
• Modified assays successfully detected the B3 variant, confirming the limitation of the original assay.

Conclusions:

• Wastewater surveillance can provide early warnings for measles introduction, even from single cases.
• Continuous monitoring and updating of wastewater surveillance assays are crucial to account for viral evolution and genomic diversity.
• Integration of genomic surveillance data is essential for maintaining the sensitivity and specificity of environmental monitoring tools.