Pathogens spread by high-altitude windborne mosquitoes

Area of Science:

• Medical entomology
• Epidemiology
• Virology
• Parasitology

Background:

• Mosquitoes migrating at high altitudes were previously thought to have limited epidemiological significance.
• The hypothesis that these airborne mosquitoes could spread pathogens over extensive distances remained untested.

Purpose of the Study:

• To investigate the epidemiological role of high-altitude windborne mosquitoes in pathogen transmission.
• To identify pathogens carried by these mosquitoes and describe the aerial pathogen-vector network.

Main Methods:

• Mosquitoes were collected using nets on helium balloons at 120-290m altitude over Mali and Ghana.
• Screening involved pan-genus qPCR for arboviruses, plasmodia, and filariae, followed by sequencing.
• A total of 1,017 female mosquitoes from 61 species were analyzed.

Main Results:

• 7.2% of mosquitoes were infected with plasmodia, 1.6% with filariae, and 3.5% with flaviviruses.
• Identified pathogens included dengue, West Nile virus, 13 Plasmodium species, and 3 filariids.
• Disseminated infections with multiple pathogens were found in species like Culex perexiguus and Anopheles squamosus.

Conclusions:

• High-altitude mosquitoes are commonly infected with infectious pathogens, including arboviruses and malaria parasites.
• This study provides the first evidence of an aerial pathogen-vector network facilitating long-distance disease spread.
• The findings suggest a significant role for windborne mosquitoes in pathogen maintenance and outbreak initiation.