Font size:
Print
Climate-Driven Vector-Borne Diseases
Context:
Climate change is increasingly being recognised as a significant factor contributing to the rising incidence of dengue fever in India.
More on News:
The changing climate patterns, characterised by higher temperatures, increased humidity, and altered precipitation, create favourable conditions for the proliferation of Aedes mosquitoes, the primary vectors of dengue.
Vector-borne diseases are illnesses caused by pathogens such as viruses, bacteria, or parasites that are transmitted to humans and animals through the bites of infected vectors, primarily blood-feeding arthropods like mosquitoes, ticks, and fleas. Including malaria (transmitted by Anopheles mosquitoes), dengue fever (transmitted by Aedes mosquitoes), Lyme disease (transmitted by ticks), and Zika virus.
Background:
- In 2023, a 12-year-old boy from Nagaland succumbed to dengue—a disease that had only been reported in the state since 2015.
- This tragic incident highlights a disturbing trend: climate change is altering the global landscape of vector-borne diseases (VBDs) like dengue, transmitted primarily by mosquitoes.
The Impact of Climate Change on Dengue Transmission:
- Rising temperatures create ideal breeding conditions for Aedes aegypti and Aedes albopictus mosquitoes, which thrive in warm, humid environments.
- Research indicates that the number of months suitable for dengue transmission in India has increased to approximately 5.6 months per year, reflecting a 1.69% annual increase from 1951 to 2021.
- A study projected that climate change could extend the dengue transmission season by two additional months in many regions of India, particularly affecting Southern, Eastern, and Central states.
- High humidity, excess rainfall, and even droughts contribute to favourable breeding conditions.
Geographic Expansion of Dengue:
- As climate change expands mosquito habitats into previously unaffected regions, areas such as Shimla, Northern Himachal Pradesh, and Jammu and Kashmir are experiencing increased dengue cases.
- Studies suggest that these mosquitoes are migrating into colder areas like the Thar Desert and the upper Himalayas as temperatures rise.
- This shift poses challenges for public health systems that may not be equipped to handle outbreaks in these novel locations.
Recent Trends and Statistics:
- The World Health Organisation (WHO) projects that climate change could expose an additional 4.7 billion people to dengue by the century’s end.
- In India, reported dengue cases skyrocketed from 28,066 in 2010 to 289,235 in 2023. This surge not only strains healthcare systems but also imposes significant socio-economic burdens.
- Urban areas are particularly affected due to higher population densities and inadequate infrastructure for managing mosquito breeding sites
- Thus, tackling VBDs is crucial for achieving broader development goals, including Universal Health Coverage and the Sustainable Development Goals (SDGs).
Challenges in Controlling Dengue:
- The lack of effective vaccines—due to the virus’s four serotypes—complicates prevention efforts.
- Current strategies focus primarily on mosquito population management rather than treating the disease itself.
- Additionally, extreme weather events linked to climate change create stagnant water pools ideal for mosquito breeding, further complicating control measures.
Recommendations:
- Utilising Insecticide-Treated Materials (ITMs): ITMs are crucial for protecting homes from mosquito bites. Studies in Mexico show that insecticide-treated screens can significantly reduce mosquito populations.
- While ITMs are part of India’s vector control strategies, their usage remains inconsistent. Increasing targeted outreach and culturally relevant messaging can enhance their effectiveness.
- Implementing Biocontrol Strategies: Given the adverse effects of chemical insecticides, biocontrol methods, such as introducing fish species like Gambusia affinis into stagnant water bodies, can be effective.
- This approach has been successfully implemented in regions like Andhra Pradesh and should be expanded to other areas.
- Strengthening Public-Private Partnerships: Collaborations between government authorities and private businesses can facilitate the distribution of low-cost ITMs and sponsor community clean-up campaigns to reduce breeding sites.
- Initiatives for Remote Areas: In remote areas, where public health infrastructure is often lacking, expanding mobile health clinics can provide rapid diagnostic testing and distribute preventive materials.
- Proactive measures, such as community inspections and educational campaigns led by ASHA workers, can help mitigate outbreaks.
- Adopting Integrated Vector Management (IVM): IVM principles should be integrated into National Disease Programmes. IVM encourages collaboration among health, agriculture, urban planning, and environmental agencies to reduce mosquito breeding.
- Fostering International Collaboration: Collaborative efforts with neighbouring countries, such as Bangladesh and Sri Lanka, can enhance regional responses to climate change’s cross-border impacts.
