Insect-borne diseases

Posted: 27 September 2007

Diseases carried by insects and other vectors affect more than 700 million people every year, and are considered the most sensitive to climatic and environment conditions.

  • Malaria, the best-known vector-borne disease, kills more people than any other communicable disease except TB.

  • About 40 per cent of the world's population, mostly those living in the poorest countries, are at risk of malaria.

  • Of these 2.5 billion people at risk, more than 500 million become severely ill with malaria every year and more than 1 million die from the effects of the disease.
Insecticide-treated bednet
Insecticide-treated bednet
The use of insecticide-treated nets has repeatedly been shown to reduce severe disease and mortality due to malaria. Credit: WHO
  • Malaria is especially a serious problem in Africa, where one in every five childhood deaths is due to the effects of the disease. An African child has on average between 1.6 and 5.4 episodes of malaria fever each year. And every 30 seconds a child dies from malaria.

  • Malaria has been estimated to cost Africa more than $12 billion every year in lost GDP, even though it could be controlled for a fraction of that sum.

  • The spread of malaria is linked with activities such as road building, mining, logging, new agricultural and irrigation projects (particularly in frontier areas), the disintegration of health services, armed conflicts and mass movement of refugees.

  • Dengue, a mosquito-borne disease, currently threatens 2.5 billion people in more than 100 countries.

  • The two primary mosquito carriers of dengue have adapted from their natural forest environments, where they breed in tree holes containing rainwater, to the urban environment where they breed in drains, water cans, pots and bottles.

  • An estimated 50 million people are infected by dengue annually, and the disease causes about 25,000 deaths.

  • Other major insect-borne diseases include yellow fever (on the increase because of deforestation and urbanisation), leishmaniasis (over 12 million people infected), sleeping sickness and Chagas disease.

  • Climate change may increase the spread of many insect-borne diseases.