Expansion and intensification of neglected tropical diseases

April 2019: Milder climates in Northern Europe and North America could lead to a global spread of mosquito-borne diseases such as Malaria and Zika. Spreading mosquito populations increase pressure on health care systems and pose high risks for global public health security.

Information

Global warming is leading to milder climates across Northern Europe and North America causing disease-carrying mosquitoes to migrate and find habitat outside the tropics. According to the WHO, mosquitos are one of the deadliest animals and are known to cause explosive outbreaks of fast spreading deadly diseases. Data suggests that rising temperatures will cause an expansion and intensification of mosquito-borne infections leading to a year-round transmission in the tropics and seasonal exposure of yellow fever, Zika, dengue, chikungunya, and other emerging diseases everywhere else. The study’s results are strengthened by increasing reports of malaria and Zika infections in Florida causing a rise in birth defects. Within the next 30 years, half a billion more people could be at risk of infection with neglected tropical diseases (NTDs). The model suggests that high temperature climate change scenarios will lead to a shift of NTDs from the tropics to Northern Europe and North America reducing the number of infections in Southeast Asia and West Africa, while intermediate climate change scenarios will cause a global surge of infections with NTDs.

Implications and opportunities

Higher densities of mosquito populations pose high risks and costs for global health systems and global health security. Mosquitos thrive best in urban environments causing additional pressure on the economy of health care systems and cities in general. While seen as highly controversial, some researchers suggest to genetically modify mosquitos and use CRISPR tools to make mosquitoes highly resistant to malaria parasites to curb outbreaks of NTDs. Nonetheless, there is a general consensus that the most efficient way of battling the expansion and intensification of NTDs is to take aggressive action to combat climate change and to map how mosquitos might move. 

Limitations

Modelling the risk of NTDs remains challenging and generally excludes significant factors such as mosquito range limits, life span, and the viral evolution of pathogens. Therefore, studies exploring the spread of NTDs should be seen within the context of included variables.

Sources

Ryan, S. J., Carlson, C. J., Mordecai, E. A., & Johnson, L. R. (2019). Global expansion and redistribution of Aedes-borne virus transmission risk with climate change. PLOS Neglected Tropical Diseases, 13(3), e0007213.doi:10.1371/journal.pntd.0007213

The Guardian. (2019). Mosquito-spread diseases may endanger millions in new places due to climate change. Retrieved from https://www.theguardian.com/society/2019/mar/28/mosquito-spread-diseases-may-endanger-millions-in-new-places-due-to-climate-change

Dong, Y., Simões, M. L., Marois, E., & Dimopoulos, G. (2018). CRISPR/Cas9 -mediated gene knockout of Anopheles gambiae FREP1 suppresses malaria parasite infection. PLOS Pathogens, 14(3), e1006898.doi:10.1371/journal.ppat.1006898