A laboratory technician collects river water samples to check for faecal coliform micro organism from the Ganges river in Varanasi on March 5.
| Photo Credit: Getty Images
The story thus far: Pathogens (normally micro organism and viruses) that trigger ailments in people and animals, could be tracked in samples taken from the atmosphere, for instance, by sampling sewage by way of wastewater surveillance. This can present early warnings for potential illness outbreaks.
How does this work?
Samples taken from sewage therapy crops, effluents from hospitals and from public areas resembling railway stations and bogs in airplanes, could be studied to see how the pathogens they include change from day-to-day. It works as a result of pathogens of curiosity are shed within the stools or urine of contaminated people. Diseases transmitted by parasitic worms resembling roundworms and hookworms will also be monitored by way of wastewater and soil samples, offering details about the burden of the illness and the effectiveness of management measures.
Rigorous protocols inform the gathering of samples. These protocols element how samples should be collected and processed, and the way pathogens are detected and analysed. By following these protocols, comparisons of pathogen load turn out to be attainable, and whole-genome sequencing permits the identification of variants of the identical pathogen.
Why is this essential?
Traditionally, the one means to determine ranges of an infection in a group was to detect infections in sufferers, known as medical case detection. However, not all contaminated individuals would possibly present signs, or may not select to be examined if signs are delicate. The variety of people who find themselves examined may not mirror the true numbers of these contaminated.
Environmental surveillance can thus present essential early warning alerts of an impending outbreak. It is now identified that the degrees of pathogen in wastewater can precede, usually by greater than per week, an increase in infections.
Why do early-warning alerts matter?
Understanding what number of contaminated individuals there are is essential for public well being planning. The extra the quantities of pathogen that flow into, the extra doubtless it is that folks will likely be contaminated. Preparing for a illness outbreak turns into a lot simpler if there’s extra discover.
Wastewater-based epidemiology has been used for over 40 years to trace a number of ailments resembling measles, cholera and polio. Such illness surveillance in India, by way of wastewater, was first initiated in Mumbai for polio in 2001. During the COVID-19 pandemic, related surveillance applications for COVID-19 had been began in 5 cities, they usually proceed to this present day.
What is India doing?
The Indian Council of Medical Research (ICMR) has not too long ago mentioned that it’s going to provoke wastewater surveillance for 10 viruses throughout 50 cities. This will allow public well being surveillance to choose up any enhance in viral load inside group settings. This extends ICMR’s involvement in establishing environmental surveillance for viruses, together with avian influenza virus, notably in areas with outbreaks. However, there is scope for enchancment. The sharing of knowledge and protocols throughout establishments and reaching frequent agreements on templates for surveillance frameworks which might be disease-specific is essential. Programmatic approaches, reasonably than project-driven approaches, should be developed that combine waste-water and different environmental surveillance with routine illness surveillance. Developing a nationwide wastewater surveillance system for India is essential.
Moreover, new methodologies are rising — audio samples of individuals coughing in public locations can be utilized to look at the prevalence of respiratory circumstances, by way of refined machine studying strategies. Thus, the probabilities of environmental surveillance are ever-increasing.
Gautam Menon is Dean, Research and Professor of Physics and Biology, Ashoka University. Views expressed are private and never of his establishment.
Published – October 01, 2025 08:30 am IST
