Wastewater Surveillance Confirms Measles Outbreak Tracking Accuracy | University of South Carolina Research

The ongoing effort to track and contain infectious disease outbreaks is gaining a powerful new tool: wastewater surveillance. Recent research, led by environmental health scientist Laura Langan at the University of South Carolina, reinforces the value of analyzing wastewater to monitor the spread of diseases like measles. This approach, known as wastewater-based epidemiology (WBE), offers a complementary method to traditional surveillance systems, potentially providing earlier warnings of surges and a broader understanding of community infection levels.

Wastewater Surveillance: A Growing Field

Wastewater-based epidemiology isn’t a new concept, but its application has expanded significantly in recent years, particularly during the COVID-19 pandemic. The principle is straightforward: by analyzing samples from wastewater treatment plants, scientists can detect the presence of pathogens – viruses, bacteria, or even biomarkers indicating infection – shed by individuals in a community. This provides a population-level view, regardless of whether people are seeking medical care or getting tested. Langan’s work focuses on refining and validating these techniques.

The recent study compared two common methods for detecting the measles virus in wastewater: reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and RT digital PCR. RT-qPCR is more widely available in public health labs, making it a practical option for routine monitoring. RT digital PCR, while more sensitive, is less accessible. The research, conducted during an active measles outbreak in Texas, aimed to determine how well these two approaches aligned in tracking the outbreak’s progression. The findings support the use of both methods, with digital PCR offering increased precision when available.

Measles Outbreaks and the Need for Enhanced Surveillance

Measles is a highly contagious viral infection that can lead to serious complications, including pneumonia, encephalitis (brain swelling), and even death. While the U.S. Declared measles eliminated in 2000, outbreaks still occur, often linked to travel to areas where the virus is circulating or among communities with low vaccination rates. According to the Centers for Disease Control and Prevention (CDC), there have been outbreaks in multiple states in recent years, highlighting the ongoing risk. The CDC reports 20 cases of measles in the US as of March 18, 2026, across 13 states. Here’s a significant increase compared to the same period last year.

Traditional measles surveillance relies on confirmed cases reported by healthcare providers and laboratories. However, this system has limitations. Many cases may be mild and go unreported, and there can be delays in reporting. WBE offers a way to overcome some of these challenges by providing an independent source of data that can detect the virus even in asymptomatic individuals or those who haven’t sought medical attention.

Understanding the Methods: RT-qPCR and RT Digital PCR

Both RT-qPCR and RT digital PCR are molecular techniques used to detect and quantify the amount of a specific genetic material – in this case, the measles virus RNA – in a sample. RT stands for reverse transcription, which converts the RNA into DNA, a more stable form for analysis. PCR (polymerase chain reaction) then amplifies the DNA, making it easier to detect.

RT-qPCR measures the amount of amplified DNA in real-time, providing a quantitative estimate of the viral load. RT digital PCR, partitions the sample into thousands of individual reactions, each containing either zero or one copy of the target DNA molecule. This allows for a more precise and absolute quantification of the viral load. Langan’s research, as detailed on her Google Scholar profile, frequently explores these “omics” approaches to environmental health.

Limitations and Considerations

While WBE holds great promise, it’s important to acknowledge its limitations. The concentration of a virus in wastewater can vary depending on several factors, including the size of the population contributing to the wastewater, the amount of water used, and the efficiency of wastewater treatment processes. The presence of the virus in wastewater doesn’t necessarily translate directly to the number of infected individuals in the community. It’s also important to note that the study focused on a single outbreak in Texas, and the findings may not be generalizable to other locations or outbreaks.

Another consideration is the cost and complexity of implementing WBE programs. While RT-qPCR is relatively accessible, RT digital PCR requires specialized equipment and expertise. Establishing and maintaining a robust WBE system requires ongoing investment in infrastructure, personnel, and data analysis capabilities.

What Does This Indicate for Public Health?

The findings from Langan’s research, and the broader field of WBE, suggest a shift towards more proactive and comprehensive infectious disease surveillance. By integrating WBE data with traditional surveillance methods, public health officials can gain a more complete picture of disease transmission patterns and respond more effectively to outbreaks. This could involve targeted vaccination campaigns, public health messaging, or other interventions.

WBE can also be used to assess the effectiveness of public health interventions. For example, by monitoring wastewater for a decline in viral load after a vaccination campaign, officials can gauge the impact of the campaign and adjust their strategies accordingly.

Looking Ahead: Expanding WBE Networks

The future of WBE likely involves expanding surveillance networks to cover more communities and monitoring for a wider range of pathogens. The National Wastewater Surveillance System (NWSS), established by the CDC, is already working to build a nationwide network of wastewater surveillance sites. This system aims to provide early warnings of outbreaks of various infectious diseases, including influenza, norovirus, and polio.

Further research is needed to refine WBE methods, improve data analysis techniques, and address the challenges associated with implementation. This includes developing standardized protocols for sample collection, analysis, and data reporting, as well as exploring new technologies for detecting and quantifying pathogens in wastewater. The work of researchers like Laura Langan at the University of South Carolina is crucial in advancing this field and realizing the full potential of WBE for protecting public health.

Ongoing monitoring and data sharing will be key to adapting surveillance strategies as new variants emerge and outbreak patterns evolve. Public health agencies will continue to refine guidance based on the latest evidence, and individuals are encouraged to stay informed through official sources like the CDC and their local health departments.