Vector-borne diseases

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Photo by Jimmy Chan from Pexels

This article was contributed by the Department of Health.

Vectors are small organisms such as mosquitoes, mites, and ticks that can carry disease from one infected person (or animal) to another person and from place to place. The diseases caused by these vectors are called vector-borne diseases.

In Hong Kong, there are several important vector-borne diseases, for example, dengue fever, Japanese encephalitis, malaria, scrub typhus, and spotted fever. Most dengue fever and malaria cases recorded are imported from endemic countries via international travel, while most cases of scrub typhus and spotted fever acquired the infection locally and had history of going to vegetated areas in Hong Kong, e.g. hiking areas, outdoor workplaces, vegetated areas near home or outdoor recreational areas.

Mosquitoes are responsible for transmitting dengue fever (Aedes mosquitoes), Japanese encephalitis (Culex mosquitoes) and malaria (Anopheles mosquitoes) while scrub typhus and spotted fever are transmitted by mites and ticks respectively.


To prevent vector-borne diseases, members of the public need to protect themselves from stings/bites of mosquitoes, mites, and ticks and help prevent their proliferation.

Protect yourselves against stings/bites

  • Wear loose, light-coloured long-sleeved tops and trousers
  • Use DEET-containing insect repellent# on exposed parts of the body and clothing
  • Take additional preventive measures when hiking or going to scrubby areas

Additional preventive measures for hiking or going to scrubby areas:

  • Wear shoes that cover the entire foot; avoid wearing sandals or open shoes
  • Tuck trousers into socks or boots to prevent arthropods from reaching the skin
  • Avoid using fragrant cosmetics or skincare products
  • Stay on footpaths and avoid walking through vegetation. Do not brush along the vegetation at the sides of footpaths
  • Avoid resting on vegetation, or at humid and dark places
  • Do not hang clothing on vegetation
  • Do not feed wild or stray animals
  • Re-apply insect repellents according to instructions

Prevent accumulation of stagnant water

  • Change the water in vases once a week
  • Avoid using saucers underneath flower pots
  • Cover water containers tightly
  • Ensure air-conditioner drip trays are free of stagnant water
  • Put all used cans and bottles into covered dustbins
  • Control vectors and reservoir of the diseases
  • Inspect and disinfest pets and pet beddings regularly
  • Store food and dispose of garbage properly to prevent rat infestation
# Pregnant women and children of 6 months or older can use DEET-containing insect repellent. For children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic and where exposure is likely, children aged 2 months or above can use DEET-containing insect repellents with a concentration of DEET up to 30%. For more information, please visit