Diseases of climate change

Indian scientists say rising temperatures will make new areas of the Himalayas vulnerable to mosquito-spread diseases. Patralekha Chatterjee reports.

Be it film actors, bureaucrats or business tycoons, everyone is keen to wade into the policy discourse on climate change in India today. But one area that is still not getting the attention it deserves is the health impacts of global warming. India’s National Action Plan on Climate Change identifies eight key “missions” to tackle various aspects of the problem, but they do not include health impacts. 

This could change in coming years as Indian scientists have begun to collect local evidence and make projections that link rising temperatures and humidity to the spread of mosquito-borne diseases like malaria. In a recent interview with the third pole, a senior World Health Organisation (WHO) official said there is evidence to suggest that rising temperatures in the Himalayan region could make many new areas vulnerable to malaria transmission.

It is early days, but government-backed studies to assess the impacts of climate change on malaria and dengue have triggered lively discussion about adaptation strategies. The Ministry of Health now has a representative from the National Institute of Malaria Research (NIMR) on the prime minister’s Council on Climate Change.

The NIMR – one of the leading institutes under the Indian Council of Medical Research – has carried out research in the Himalayan region and found incidents of malaria in hilly areas of Nainital district in Uttarakhand state in northern India. “Dengue was first reported in the district in 1996. Now it is being reported frequently. Similar phenomena have been noticed in Nepal and Bhutan, where dengue was reported for the first time in 2004,” said Dr Jai P Narain, director of the Department of Sustainable Development and Healthy Environments in WHO’s Regional Office for South-East Asia.

Last November, India’s Ministry of Environment and Forests released its first assessment report of the projected impacts of climate change by the 2030s on key sectors in the country’s climate-sensitive regions, including the Himalayas and the north-east. The report was among the first to flag a study by scientists at the NIMR that established a nexus between climate change and health. These studies suggest that climate change will significantly increase both the intensity and geographic spread of malaria and other vector-borne diseases in areas which have been largely insulated from them in the past. 

Based on regional climate projections made by the Indian Institute of Tropical Meteorology (IITM), a group of NIMR scientists led by Dr RC Dhiman looked at the effect of climate change on malaria transmission in four regions in India – the Himalayas, the coast, the north-east and the Western Ghats.

The IITM predicts that temperatures in the Himalayan region will increase by 0.9 degrees Celsius on 1970s levels, to 2.6 degrees, by the 2030s and rainfall intensity will increase from 2% to 12%. Based on these projections and their own field observations, Dhiman and his colleagues conclude that malaria is likely to spread into new areas of the states of Jammu & Kashmir and Uttarakhand, and affect people for a longer period every year in the north-eastern states and other parts of the country. Of course, as the study points out, “projections based on climatic parameters should not be viewed with certainty for malaria incidence, since malaria transmission dynamics is a multi-factorial one, of which intervention measures play a major role.”

However, given the study concludes that climate change is “likely” to impact health in various regions across the country, the question becomes: what should be done about it?

Dhiman told the third pole: “It is legitimate to ask why we should worry about malaria in a few more new pockets when so many districts are already malaria-endemic. But the real concern is the complete lack of awareness in areas which, to date, have not grappled with malaria. There is an urgent need to educate health workers in areas which may not have seen malaria in the past but which could now confront the disease due to changes in relative humidity and temperature. At the moment, health workers in these areas have no idea what to do.”

“Health education has to begin with raising awareness of symptoms,” said Dhiman. “The action plans for these new regions which could become susceptible to malaria with rising temperature and humidity have to incorporate lessons learnt from parts of the country which are already struggling with malaria.

"Inaccessible terrain in hilly remote areas, lack of adherence to medication and incomplete treatment, advocacy in a language and idiom not understood by communities are some of the factors which act as roadblocks in the field.”

Dhiman also pointed out cultural barriers to effective action: “There have been many instances where families have prevented health workers from spraying insecticide in corners where a deity may be standing.” This leaves areas where mosquitoes can continue to breed and undermines attempts to prevent the spread of the disease.

At least the spread of malaria due to climate change has been systematically studied and further studies on malaria and heat stress are in the pipeline. But the same cannot be said for other vector-borne diseases such as dengue and chikungunya, as WHO’s Narains pointed out. Studies on the impact of climate change on nutrition as well as respiratory illnesses and water-borne diseases like diarrhoea are also urgently needed, he said.

WHO’s South-East Asia Regional Office has developed standard practices to study the impact of climate change on vector-borne and diarrhoeal diseases. “Two retrospective studies of vector-borne diseases in Nepal and diarrhoeal diseases in Kolkata, India, have just been completed and more studies are being carried out in other countries in south-east Asia,” said Narain.

According to hydrologists, one of the effects of climate change and the consequent faster-paced melting of glaciers in the Himalayas is that there will be more water in the north India’s rivers for the next two decades, and subsequently far less water than now. In both cases, people will become more vulnerable to water-borne diseases like diarrhoea.

The research findings have triggered policy responses. A task force established by India’s Ministry of Health & Family Welfare is developing action plans for areas likely to be affected. But the real need is for local-level action to generate awareness about the link between climate change and health. In vulnerable areas, communities need to be made aware of the symptoms of new diseases, methods of prevention and the importance of intervention measures. Narain warns it is also necessary to “strengthen health infrastructure in terms of manpower, logistics, surveillance systems and new tools of intervention”.

Patralekha Chatterjee is a writer and photographer based in New Delhi.

Homepage image from Sanofi Pasteur