Multiplexed Detection, Partitioning, and Persistence of Wild-Type and Vaccine Strains of Measles, Mumps, and Rubella Viruses in Wastewater

Wastewater surveillance of vaccine-preventable diseases
may provide
early warning of outbreaks and identify areas to target for immunization.
To advance wastewater monitoring of measles, mumps, and rubella viruses,
we developed and validated a multiplexed RT-ddPCR assay for the detection
of their RNA. Because the measles–mumps–rubella (MMR)
vaccine is an attenuated live virus vaccine, we also developed an
assay that distinguishes between wild-type and vaccine strains of
measles in wastewater and validated it using a wastewater sample collected
from a facility with an active measles outbreak. We also evaluated
the partitioning behavior of the viruses between the liquid and solid
fractions of influent wastewater. We found that assaying the liquid
fraction of the wastewater resulted in more sensitive detection of
the viruses despite the fact that the viral RNA was enriched in the
solid fraction due to the low solids content of the influent wastewater.
Finally, we investigated the stability of measles, mumps, and rubella
RNA in wastewater samples spiked with viruses over 28 days at two
different concentrations and two temperatures (4 °C and room
temperature) and through freeze–thaw and observed limited viral
decay. Our study supports the feasibility of wastewater monitoring
for measles, mumps, and rubella viruses for population-level surveillance.