Aditi Paul, CDKN’s country programme manager for India reflects on the link between climate change and the ongoing dengue virus outbreak in New Delhi

India’s capital city New Delhi is now in the grip of a deadly dengue epidemic. It has only been a couple of months since India has recovered from a searing heat wave that left many dead.

Dengue is an extremely dangerous mosquito-borne virus, infecting 100 million people annually, and killing 20,000 each year according to the World Health Organisation (WHO); there is currently no vaccine or cure for this often-fatal disease worsening our health and well being. Considered to be urban-centric, the most at risk arechildren, especially those from poorerareas, the elderly, andthose with underlying health issues.

With 1,800 cases reported in past few weeks, including fatal cases the recent outbreak of dengue in New Delhi, has actually posed serious questions on both the efficiency of the local health infrastructure and preventive management of infectious diseases and well being.Then there is climate change; many public health practitioners believe has led to temporal (window period of transmission) and geographical expansion of the virus and its vector – the female mosquitoes (Aedes).

The climate connect  

Transmission of the dengue virus is dependent on weather conditions, especially temperature variances, rainfall and relative humidity. Studieson the potential impacts of climate change on dengue spread indicates increased climatic suitability with increasing warmer and wetterconditionslengthening the transmission period.Under certain conditions, inter-annual deviation in local or regional climate linked to El-Nino may regulate the temporal and spatial dynamics of dengue.

According to IPCC findings, modeling studies (Jetten and Focks, 1997; Martens et al., 1997; Patz et al., 1998a) suggest that a warming projection of 2°C by 2100 will result in a net increase in the potential range, and duration of the dengue menace.

Non-climatic stressors

According to the study conducted by United Nations University of International Institute for Global Health, vector borne diseases are not only spreading to areas of the world not infected before but are also beginning to turn into epidemics. Both climatic and non-climatic stressors are responsible for current conditions.

The study applied a Water Associated Disease Index to understand vulnerability to dengue at a global scale. The study considered the propensity of a system to be adversely affected by dengue, conditions that support the presence and transmission of the disease and the socio-economic, and political condition that reflects community and individual susceptibility level.

The study led to dengue-infected vulnerability maps - both at the global and country level; India came in as highly vulnerable, located closer to equator, with conditions ideal for dengue to prosper such as high population density, inadequate urban planning and municipal services (sanitation and waste management), low access to health care facilities, and lack of climate compatible public health policies and control measures.

Thus, the combined effect of climate change and deficiencies in pro-active and preventative planning systems of both land-use patterns and public health care system have caused the crisis which now grips New Delhi.

How to arrest the threat

Climate change is here. The question is now of adaption and mitigation. The global community agreeing to achieve a legally binding and universal agreement on climate change, with the aim of keeping global warming below 2°C at this year’s COP21 may help bring some relief. We also need to consider preventive measures;effective ones by educating communities about the risks from climate change and its impact including spreading infectious diseases.

Community awareness has always been a challenge especially in countries like in India where about one third of the global poor reside; outreach is difficult. However, there are innovative models ideas which work well, such as CDKN’s Heat Health initiative in India. The project’s media campaign, in vernacular language utilised local radio and text messaging to spread the message.Similarly, another CDKN sponsored project on disaster risk management in Gorakhpur translated complex climate science information into the local language and again used text messaging to keep farmers in the loop. The project also experimented with the ‘Women of the Community’ concept – transforming them into ‘Change and Chain Agents’ for sharinglessons with the community. ‘Nukkad Natak’ (Street Theatre Workshops) proved popular; visual expressionshaving a bigger impact where literacy is low!

India has recently announced over a hundred ‘Smart City Schemes’, with the objective ofpromotingeconomic growth, improve governance, and the delivery more effective and efficient public services. Climate change and pollutionare, however, low on the agenda. An integrated approach of build and remodeling the cities is required - where affordable housing with livelihood support and climate change adaptation measures are at the top of the development agenda.

Successful future management of infectious diseases from climate change requires an understanding of the dynamics of the virus, host, vector, and environmental factors especially in the context of a changing climate. A proper representation would be that public health and climate change are inter-connected.

Picture Courtesy: Gurinder Osan/AP