level of risk of exposure to malaria and what affects it
Last edited 12/2019 and last reviewed 10/2020
Level of risk of exposure to malaria and what affects it
Exposure of individual travellers to malaria is influenced by the number of infectious bites received
Factors affecting the number of infectious bites received are given below:
- Temperature, altitude and season
- optimum conditions for malaria transmission are high humidity and an
ambient temperature in the range 20 to 30 degrees C
- Malaria transmission does not usually occur in regions with temperatures
below the 16 degrees C isotherm (line on a weather map joining all
the places that have the same temperature)
- Malaria transmission does not usually occur in regions with temperatures
below the 16 degrees C isotherm (line on a weather map joining all
the places that have the same temperature)
- parasite maturation in the mosquito usually cannot take place at altitudes
greater than 2000 metres
- has been reported at altitudes up to 2500 metres in some countries
- has been reported at altitudes up to 2500 metres in some countries
- seasonal rainfall increases mosquito breeding and in some areas malaria
is highly seasonal
- optimum conditions for malaria transmission are high humidity and an
ambient temperature in the range 20 to 30 degrees C
- Rural versus urban location
- Malaria incidence is generally higher in rural than in urban areas,
especially in Africa where the intensity of transmission is on average
about 8 times higher in villages than towns but as Africa becomes increasingly
urbanised, the risk of contracting malaria in African or other cities
of malaria-endemic areas must not be discounted
- Malaria incidence is generally higher in rural than in urban areas,
especially in Africa where the intensity of transmission is on average
about 8 times higher in villages than towns but as Africa becomes increasingly
urbanised, the risk of contracting malaria in African or other cities
of malaria-endemic areas must not be discounted
- Type of accommodation
- an impregnated bed net should be used unless the accommodation is fitted
with functioning air-conditioning and windows and doors which are sufficiently
well sealed to prevent mosquito entry
- backpackers staying in cheap accommodation have a higher risk of being
bitten compared to tourists staying in air-conditioned hotels
- a traveller should embark on their journey equipped with mosquito protection
measures appropriate to their particular circumstances
- an impregnated bed net should be used unless the accommodation is fitted
with functioning air-conditioning and windows and doors which are sufficiently
well sealed to prevent mosquito entry
- Patterns of activity
- being outdoors between dusk and dawn when Anopheles mosquitoes bite
increases the risk
- being outdoors between dusk and dawn when Anopheles mosquitoes bite
increases the risk
- Length of stay
- longer the stay, the higher the risk of contracting malaria
Reference:
- Public Health England. Guidelines for malaria prevention in travellers from the UK 2019.