As global temperatures rise and weather patterns shift, the spread of vector-borne diseases such as malaria, dengue, and chikungunya is expanding, posing significant risks to human health. A comprehensive review by the World Health Organization (WHO), in partnership with Reaching the Last Mile (RLM), highlights the urgent need to understand and address these changes. This study underscores critical gaps in knowledge and the disproportionate impact on vulnerable communities.
IMPACT OF CLIMATE CHANGE ON VECTOR-BORNE DISEASES
The WHO and RLM study reveals that rising temperatures and changing weather patterns are significantly altering the geographic spread of disease vectors, particularly mosquitoes. This expansion increases the risk of introducing these diseases to new, previously unaffected areas, leading to severe health implications.
KEY FINDINGS
Expansion of Disease Vectors:
- Mosquito vectors responsible for diseases like malaria, dengue, and chikungunya are expanding their range.
- This expansion increases the risk of disease outbreaks in new regions, particularly affecting communities already vulnerable to health disparities.
Geographic and Altitudinal Shifts:
- Malaria transmission is likely to move both polewards and to higher altitudes.
- The mosquito vector for dengue and chikungunya is predicted to continue expanding its geographic range.
Underrepresented Data on NTDs:
The study found a significant underrepresentation of data on other neglected tropical diseases (NTDs), highlighting a gap in comprehensive research and understanding.
STUDY ANALYSIS
The study reviewed peer-reviewed papers from January 2010 to October 2023, analyzing data on national disease burdens, healthcare access, and climate vulnerability scores. The majority of data focused on malaria, dengue, and chikungunya, with other NTDs significantly underrepresented. In total, 42 693 records were retrieved, from which 1543 full-text papers were examined. Researchers correlated the number of publications with national disease burdens, the Healthcare Access and Quality Index (HAQI), and climate vulnerability scores. Of the 511 papers that met the inclusion criteria, 185 papers addressed malaria, 181 focused on dengue and chikungunya, and 53 reported outcomes on leishmaniasis. Other NTDs, however, were significantly under-represented, having not been sufficiently studied.
NEED FOR COMPREHENSIVE RESEARCH AND ACTION
“The findings presented in this major review highlight the need for more comprehensive, collaborative, and standardized modelling, so that we can better understand and predict the effects of climate change on malaria and NTDs, both directly and indirectly,” said Dr Ibrahima Socé Fall, Director of WHO’s Global NTD Programme, who led the study. “This important and timely review reveals alarming trends and is a call to urgent action. Malaria transmission is likely to shift both polewards and to higher altitude, while the mosquito vector responsible for transmission of dengue and chikungunya is predicted to continue to expand its range. If we are to protect and build upon the hard-won victories of the past two decades, the time to mobilize is now.”
“The climate crisis has the potential to reverse decades of progress in global health and development, said Tala Al-Ramahi, Chief Strategy Officer of Reaching the Last Mile. “Greater investment in research is urgently needed to support the development of timely and evidence-based interventions, and to allow us to anticipate and mitigate the worst consequences of climate change on human health.”
“We have recently seen the consequences of extreme weather events on malaria, and they are only predicted to become more commonplace. The paper provides a clarion call for mitigation and evidence responsive adaptation to climate change,” said Dr Daniel Ngamije Madandi, Director of the WHO’s Global Malaria Programme. “As the impact of climate change is likely to be disproportionately borne by the poorest people, who are also disproportionately affected by malaria and NTDs, a more equitable, comprehensive and sustainable response is needed.”
MITIGATION AND ADAPTATION
The study found that only 34% of reviewed studies addressed mitigation strategies, and a mere 5% focused on adaptation methods. This lack of evidence underscores the necessity for increased investment in research to protect progress made against malaria and NTDs.
The WHO and RLM study provides a crucial overview of how climate change is altering the spread of vector-borne diseases, with significant implications for global health. There is an urgent need for more comprehensive, collaborative research to develop effective strategies to combat these changes. Policymakers must prioritize promoting the availability, affordability, and accessibility of unprocessed or minimally processed foods to support global public health.
