HIGH-ALTITUDE MOSQUITO FLIGHTS MAY SPREAD PATHOGENS OVER HUNDREDS OF KILOMETRES: STUDY

NEWS – A new multi-country study has provided direct evidence that mosquitoes flying at high altitudes can carry infectious pathogens, potentially spreading diseases far beyond local transmission zones. The findings, published in Proceedings of the National Academy of Sciences (PNAS), challenge traditional assumptions in public health planning.

HIGHLIGHTS

Where and How Was the Study Conducted?

• Conducted in West Africa (Mali and Ghana)
• Method:
  • Helium balloons with nets suspended 120–290 m above ground
  • Sampling conducted over 191 nights (2018–2020)
• Mosquitoes identified using DNA sequencing
• Pathogens detected using PCR-based screening

Key Findings

• Sample Size
  • 1,017 female mosquitoes
  • Belonging to 61 species
• Infection Rates
  • 8% carried Plasmodium (malaria parasites)
  • 5% carried flaviviruses
  • 6% carried filarial worms
• Transmission Potential
  • Disseminated infections (head + thorax):
    • 6% Plasmodium
    • 1% flaviviruses
    • 6% filariae
  • Indicates mosquitoes capable of infecting new hosts
• Pathogens Detected
  • Human disease agents: Dengue virus, West Nile virus, M’Poko virus
  • 15 bird Plasmodium species
  • Several filarial nematodes

Why This Matters

• Demonstrates wind-assisted mosquito migration across tens to hundreds of kilometres
• Suggests disease spread may occur without human or animal movement
• Highlights risk of sylvatic (wildlife-based) pathogen transmission
• Ground-level surveillance alone may miss critical transmission dynamics

Public Health Implications

• Need to monitor high-altitude mosquito corridors
• Integrate wind pattern analysis in disease forecasting
• Enhance downwind surveillance during transmission seasons
• Prepare rapid response strategies for new outbreak zones