Physicians and climate action: Global impact of climate change on dengue virus

Sir,

Climate change is widely acknowledged to influence human pathogenic diseases; nevertheless, the comprehensive magnitude of this threat remains inadequately quantified. The vector-borne diseases and their propagation routes, exacerbated by climatic concerns, are excessively diverse in terms of taxonomic and transmission types, making it challenging to cope with social adjustments on a global level. ¹ Currently, vector-borne diseases affect more than 80% of the worldwide population, with mosquito-borne illnesses being the primary contributors to the cumulative disease burden. ² Approximately, >50% of recognised human infectious diseases are expected to be aggravated by climate change if climatic hazards continue to influence the environment at the current pace and intensity, with most of these diseases being vector-borne, the dengue virus being the most prominent. ³ Changes in climate, influenced by humidity, temperature and wind, or other climatic hazards such as warming, flooding, and precipitation, can enhance various aspects of the arthropod vector development process,thus, influencing population dynamics, migration patterns, survival rates, disease transmission, and the dissemination of pathogens via vectors. ⁴

By 2050s, a minimum of three billion individuals globally will be susceptible to dengue. ⁵ A one-degree Celsius rise in temperature could elevate dengue fatality by as many as 710 cases. ⁶ The geographic spread of the dengue virus, along with other arboviruses, has undergone significant changes due to climate change over the past few decades. ⁷ The rise in global temperatures, increased humidity, surface pressure, and decreased rainfall are climate change-triggered effects contributing to the expansion of the geographical limits of Aedes aegypti. However, the speed of the wind, precipitation, and sky clearance index exhibit a negative correlation with dengue incidence. Moreover, the prolongation of the transmission season, human migration patterns from tropical to developed regions, and the augmentation of breeding locations in various parts of the world are potentially heightening the likelihood of transmission due to climate change. ⁸

Network research utilising Gephi software showed high-traffic destinations, including Bangkok, Singapore, and Rio de Janeiro, as new hubs for the global spread of dengue. ² Similarly, South China and the states of California, Texas, Florida, and Puerto Rico in the United States are also facing an increased incidence of the climate change-triggered dengue virus.^8,9,10,11 Hence, the increased incidence of dengue virus due to climate change is being observed worldwide.

In conclusion, the overall global impact of climate change on the dengue virus necessitates climate action to limit the spread of the disease, given its association with climate change. Physicians must advocate for the reduction of global temperatures, along with the promotion of vector control, and prioritise climate-resilient healthcare systems, medically safe human migration, and the development of climate change adaptation strategies. Public awareness and interdisciplinary collaborations to monitor trends and construct evidence-based interventions at the local level will effectively reduce the risk of disease influence and capacity for spread due to climate change.