“The Indian Council of Medical Research (ICMR) has found that migratory birds transport seven zoonotic bacterial pathogens which may cause grave harm to human health,” claimed Dr Sandeep Chaudhari, Professor and Head, Department of Veterinary Public Health and Epidemiology, Nagpur Veterinary College (NVC) while interacting with ‘The Hitavada’. ICMR is leading a national-level study to investigate migratory birds transporting disease-causing bacteria carrying antimicrobial resistance (AMR) genes. Dr Chaudhari, along with his team, is responsible for analysing the bacteriological samples obtained in this project. So far, they have identified seven important zoonotic bacterial pathogens in the samples -- Escherichia coli (E coli), Salmonella, Listeria, Shigella, Yersinia, Campylobacter and Leptospira, that are an immediate cause for concern in terms of public health. The study, involving 17 collaborating institutions, is attempting to trace these pathogens, understand how they move across different ecosystems, and strengthen India’s preparedness against future disease threats. Unlike viruses, which frequently mutate into new strains, bacteria often develop resistance by acquiring AMR genes. This allows them to survive medicines that were previously effective.

 

Dr Chaudhari warned that antimicrobial resistance poses one of the greatest long-term threats to global health. “If AMR spreads on a pandemic scale, controlling it will be extremely difficult because no new class of antibiotics that can combat AMR diseases has been developed for more than a decade,” he explained. “We are trying to find the root cause of where these pathogens are arising from. NVC is specifically focusing on bacterial pathogens of zoonotic significance. We are investigating whether they harbour AMR genes that could eventually make infections difficult or even impossible to treat,” he added. Dr Chaudhari explained that migratory birds release these pathogens into the environment through their droppings, respiratory secretions, nasal discharge and other body fluids, and infect local birds. Local birds have a relatively higher body temperature, which is why even the presence of these pathogens do not have any clinical manifestations.

 

Human bodies have ideal body temperatures required for the pathogens to multiply and cause diseases, and the AMR genes render them untreatable. ‘One Health’ approach: The research adopts the ‘One Health’ approach, which means an understanding that the health of humans, animals and the environment is interconnected. Rather than studying diseases in isolation, the project examines how pathogens move between wildlife, livestock, people and the environment, and provide a more comprehensive understanding of disease transmission. Dr Chaudhari explained that pathogens shed into the environment through bird droppings may contaminate soil and water, eventually entering the food chain. Some bacteria can be absorbed by plants through their roots and seep into plant tissues. His laboratory has previously identified ‘Listeria monocytogenes’ in the inner tissues of leafy vegetables. This can cause listeriosis, a serious food-borne infection, which may be dangerous for pregnant women, children, and other vulnerable groups.

 

“Since vegetables such as lettuce, cabbage and other leafy greens are frequently consumed raw in salads, maintaining proper food hygiene and safe agricultural practices is an important precautionary measure,” he explained. Recent examples of diseases caused by bacteria are the 200 cases of Guillain-Barré Syndrome (GBS) outbreak linked to contaminated drinking water (often containing Campylobacter jejuni) that were found in Pune in February-March 2025. Another example is the recent health advisory issued for Leptospirosis caused by the bacteria Leptospira. This was issued by Mumbai’s Brihanmumbai Municipal Corporation (BMC), after the city faced heavy rainfall and flash floods in July 2026. By identifying disease-causing bacteria, studying their antimicrobial resistance and tracing their movement across international waters, ICMR-led initiative aims to build an evidence base that can guide development of medicines, biosecurity measures, and public health policies before the next major disease challenge emerges.

 

The project has already analysed more than 2,000 samples. Trained teams from the Bombay Natural History Society (BNHS) and ELA Foundation humanely capture and tag migratory birds before collecting tracheal swabs, faecal samples, blood samples from larger birds, and ectoparasites such as ticks and mites. Standard operating protocols have been developed jointly by all participating institutions to ensure samples are collected, transported and analysed uniformly across the country. Different transport media are used for bacterial and viral samples to preserve their integrity before laboratory testing. 

 

Dr Chaudhari also explained that nearly 75 per cent of emerging infectious diseases originate in wildlife, making surveillance of wild animals increasingly important. He added that migratory birds return to the same breeding sites year after year, allowing researchers to monitor recurring migration patterns through tagging programmes conducted by BNHS. As birds move between countries, they may also carry different pathogens across ecosystems.