CDC report notes challenges of using wastewater detection for measles, other viruses

A Centers for Disease Control and Prevention report released July 16 found that wastewater surveillance failed to detect an internationally circulating measles genotype that accounted for about 5% to 10% of U.S. measles cases in 2025, highlighting potential challenges of using wastewater surveillance as a public health tool. The report said that of two unrelated measles cases reported to the Wisconsin Department of Health Services in February 2026, wastewater surveillance detected one case before the case was reported. The second, caused by the international B3 genotype, was undetected. Public health officials later released a modified laboratory procedure that improved the detection of the B3 genotype. The CDC said that wastewater testing should be standardized and revalidated against circulating viruses and supported by publicly available whole-genome sequencing data.