Flood, rising mercury increasing risk of leptospirosis
Source: Chronicle News Service / Nongmaithem Debarani

Imphal, March 25 2025: Adverse weather changes driven by climate change can lead to a wide range of issues, from natural disasters to socio-economic challenges and beyond.

For years, movies have depicted dramatic scenarios of melting glaciers or rising sea levels triggering apocalyptic events, such as zombie invasions or mass extinctions.

Now, such fictional narratives are not far from reality.

Climate change, a natural phenomenon, is being accelerated by human activities, making its impacts increasingly visible in our daily lives.

The outbreak of Leptospirosis, a zoonotic disease, is one such impact, which affects both humans and animals.

Flood, rising mercury increasing risk of leptospirosis

It is a serious public health issue, with epidemiological analysis showing a rise in cases during monsoon season in endemic states like Kerala, Andaman & Nicobar Islands, and recently, in Manipur.

Leptospirosis is an infectious zoonotic disease caused by the Leptospira bacteria, transmitted primarily through drinking or contact with water contaminated by urine or body fluids of infected animals, and also exposure to the urine or body fluids of infected animals such as rodents, raccoons, opossums, cattle swine, dogs, horses, buffaloes, sheep, goats and wildlife.

The disease can lead to potentially fatal infections, including liver damage, kidney failure, meningitis, or respiratory distress.

Recent studies suggest a significant correlation between leptospirosis outbreaks and climate change, with increasing temperature, rainfall, and flooding events acting as key drivers in the spread of the disease.

Frequent and intense rainfall, exacerbated by climate change, increases the likelihood of flooding.

Floodwaters can become contaminated with Leptospira bacteria from animal waste, particularly from rodents and livestock, leading to greater exposure to the pathogen.

However, as it was seen during the flooding incident last year, people ignoring the dangers and wading through the flood waters, as a form of entertainment or sightseeing.

Rapid urbanisation and inadequate drainage systems contribute to the stagnation of floodwaters, providing a sustained environment for the bacteria to thrive.

Warmer temperatures, a direct result of climate change, may create favourable conditions for the bacteria to multiply, allowing it to persist for longer periods in the environment, further increasing the chances of human exposure.

With climate change shifting the distribution patterns of wildlife, including rodents, which serve as primary reservoirs for the bacteria, they may bring the bacteria into new regions, spreading the disease further.

The symptoms of leptospirosis can develop anywhere from two to four weeks after being exposed to the bacteria.

Symptoms may include fever, headache, myalgia, weakness vomiting, diarrhoea, abdominal pain, jaundice, skin rash and red eyes.

However, often times, the symptoms are mistaken for flu.

Patients also often go for over the counter medications to treat some of the symptoms, mistaking it for other infections.

It is estimated that more than one million people worldwide get leptospirosis each year, of which 60,000 are fatal cases.

Leptospirosis consists of two phases - Leptospiremic phase (acute or septicemia phase) and immune (delayed) phase.

In the acute phase, the patient will experience a sudden onset of flu-like symptoms, lasting between 3-10 days.

During this phase, test will reveal the presence of the bacteria in the blood.

In the immune phase, the bacteria have moved from the blood stream to the organs.

A small number of people could develop Weil's syndrome which causes internal bleeding, kidney damage and jaundice.

The patient will also start coughing up blood or discharge blood in urine or stool.

While Leptospirosis can be contracted by contact with contaminated water, the people most at risk are those who work outdoors or with animals including farmers, miners, sewer workers, slaughterhouse workers, veterinarians, animal caretakers, fishermen, dairy farmers and military personnel.

People involved in outdoor activities such as swimming, rafting and kayaking also face an increased risk.

If a person suspects he/she has been exposed to leptospirosis or is experiencing symptoms, one should immediately seek medical attention.

Once the infection is confirmed, it would likely be treated with antibiotics.

Timely treatment is the most effective cure for this disease.

The symptoms in infected animals are almost the same as infected human such as fever, lethargy, vomiting, diarrhoea, jaundice, and in severe cases, kidney or liver failure.

According to NOHPPCZ regional co-ordinator and principal investigator and Department of Microbiology head assistant professor Dr Shakti Laishram, there is almost zero data with regard to the spread of leptospirosis in the north-eastern states including Manipur.

She continued that several animals in Imphal East tested positive for the bacteria last year, following the flooding.

A sample taken from a person in Tentha in Thoubal district also tested positive but the data could not be confirmed.

Explaining the reasons for non-confirmation, Dr Shakti stated that for diagnosis of leptospirosis, both IgM ELISA and Truenat (real time PCR) test offer rapid detection but due to limitations of longer turnaround time, skilled personnel and infrastructure required by the latter, the ELISA test is generally conducted in the state.

However, the accuracy level varies.

Another factor fo consider is that the leptospira bacteria specimen found in one place would differ from those found in other locations.

As such, the specimen found in Manipur would be different from those found in other places.

Thus, when any potentially positive sample is sent to one of the NCDC testing centres outside the state for further testing by Microscopic Agglutination Test (MAT), the sample could test negative due to differences in bacteria specimen.

Informing about the plan of action with regard to dealing with this disease, Dr Shakti informed that four pilot surveys/ projects have been launched in Imphal East, Imphal West, Thoubal and Bishnupur districts, in view of the need for urgent investigation.

If a person tests positive, then his/her surrounding environment needs to be checked to ascertain the cause of the infection and curb any spread of the same.

She also emphasised the need for more awareness on zoonotic infections and coordination between the different government departments to work together.

Meanwhile, an officer of the Department of Veterinary and Animal Husbandry opined that while animal owners, either of livestock or pets, welcome any sort of survey, sample collection, intervention or vaccination drive for their animals, they become hesitant in providing samples when it comes to zoonotic related cases.

The owners often times do not want to provide their own blood samples, in areas where animals have tested positive for zoonotic cases and there is potential risk of an outbreak.

Thus, the officer stressed the need for both livestock and pet owners to be more prudent in this regard.

In light of all these, the government needs to invest in improving surveillance systems to track the incidence of leptospirosis, especially in rural and flood-prone areas.

Early detection can help identify outbreaks before they spread and provide timely medical interventions.

Monitoring the environmental conditions such as rainfall patterns, temperature fluctuations, and flooding events, can help predict potential leptospirosis outbreaks.

Furthermore, the development of robust drainage systems and flood barriers must be prioritised.

This includes both structural and natural solutions, such as restoring wetlands to absorb excess water and reducing urban sprawl.

Infrastructure in high-risk areas should be designed with climate resilience in mind, to limit contact With contaminated water.

At the community level, organising awareness campaigns and educating communities, especially those in flood-prone areas, about the risks of leptospirosis and the importance of personal hygiene, such as wearing protective boots and gloves during floods, can reduce the transmission of the disease.

At the individual level, a person should get the pets vaccinated, avoid any contact with animal urine or body fluids especially if one has a cut or abrasion of the skin.

One should avoid swimming, walking or swallowing water that may contain animal urine.

The awareness campaigns should also stress the importance of avoiding contact with contaminated water especially during flooding and seeking early medical attention if symptoms appear.

Rodent control programmes, improving waste management systems, vaccination drives targeting livestock and pets, especially in rural and flood-prone regions, and improving access to medical care is critical in preventing severe outcomes.

Rapid response healthcare teams should be deployed in flood-prone areas to provide immediate treatment and reduce fatalities.

Leptospirosis is a preventable disease, but its incidence and spread are increasingly influenced by climate change.

The intensification of weather events, such as floods, along with rising temperatures, can create environments where leptospirosis thrives, leading to more frequent outbreaks.

By addressing both the direct and indirect effects of climate change, we can better protect vulnerable populations and mitigate the public health burden of leptospirosis in the future.

Dr Ranjana Khuraijam, Mother's Care Children Hospital and Research Centre head of Research and Development & Laboratory director said that a better human and animal society is the best gift we can give to the future generation.

Thus, we can reduce the burden of leptospirosis and create a safer, healthier environment for communities vulnerable to climate change with concerted efforts.

(The report is filed under the 5th Media Fellowship Programme on Climate Change Reporting under the sponsorship of Directorate of Environment and Climate Change, Government of Manipur) .