Thar desert dust storms may be bringing disease-linked bacteria to Himalayas

Dust storms from western India can ferry disease-linked bacteria to the Eastern Himalayas, reshaping mountain air and raising public health concerns, a new Indian study shows

Air over the Himalayas, regarded as clean and pollution- and pathogen-free, may be carrying bacteria transported from distant deserts. A new study has found that dust storms originating in the Thar desert of western India can ferry airborne bacteria, including disease-linked species, across hundreds of kilometres to the Eastern Himalayas, altering the region’s atmospheric microbial composition.

 

The study, titled Long-range transported bacteria perturbing airborne bacterial diversity and pathogenicity over Eastern Himalayas, India, published in Science of the Total Environment, shows that seasonal dust transport can introduce bacteria associated with respiratory, skin and gastrointestinal illnesses into high-altitude environments, raising fresh public health concerns for Himalayan communities.

What did the study find?

Over more than two years, researchers from Kolkata’s Bose Institute continuously monitored airborne particles at a Himalayan site to track both chemical pollutants and microbial communities.

 

They combined atmospheric measurements with transport modelling to trace where these microbes were coming from, and how they reached such remote heights.

 

According to the study, during the pre-monsoon months, strong winds lift dust from western Indian deserts, including the Thar, which then travels eastwards, sweeping across the densely populated Indo-Gangetic Plain before rising and drifting towards the Eastern Himalayas.

 

Dust particles act like tiny vehicles. As they move, they carry bacteria embedded on their surfaces, protecting them during the long atmospheric journey.

 

The analysis identified several bacterial species known to be associated with respiratory, skin and gastrointestinal illnesses. While the study does not claim these bacteria will automatically cause disease, their presence in mountain air raises important red flags.

 

It shows, for the first time with direct evidence, that potentially pathogenic bacteria can be delivered to high-altitude regions through long-range atmospheric transport. 

Why does the Indo-Gangetic Plain matter in this journey?

The Indo-Gangetic Plain is one of the most polluted regions in the world. As desert dust passes over it, the plumes mix with polluted air rich in locally generated microbes.

 

This mixing changes the biological makeup of the dust cloud. By the time it reaches the mountains, the air mass carries a blend of desert-origin bacteria and microbes picked up from urban and agricultural regions.

Why are Himalayan populations particularly vulnerable?

The study highlights that life at high altitude already places stress on the human body, as cold temperatures and chronic hypoxia (lower oxygen levels) can weaken immune responses. Adding airborne exposure to disease-linked bacteria could increase health risks for Himalayan communities, especially children, older adults and those with existing illnesses.

 

The researchers also found that alongside long-distance transport from western deserts, there is vertical uplift of air from the Himalayan foothills.

 

Local pollutants and microbes are lifted upward and mix with incoming desert dust. Together, these local and distant bacterial communities reshape the atmospheric microbiome over the mountains.

Could this explain infections seen at high altitudes?

The scientists suggest this combined microbial influx may help explain why certain infections, including gastrointestinal illnesses, occur even in sparsely populated, high-altitude regions.

 

Until now, such illnesses were often attributed only to local hygiene or water issues. The study adds airborne exposure as a plausible contributing factor.

 

The researchers have underscored the need to consider biological agents such as bacteria, fungi and viruses as part of air quality systems that focus almost entirely on chemical pollutants like PM2.5, nitrogen dioxide or ozone.

 

The researchers argue that this is a major blind spot. Incorporating routine microbial surveillance into air quality frameworks could significantly improve public health preparedness.