Transmission Patterns in the Asia-Pacific
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Malaria intensity varies throughout the region. In some countries the majority of the population (over 90%) live in areas of high falciparum malaria transmission, these countries include Papua New Guinea, Myanmar, parts of Indonesia, Bangladesh, Solomon Islands, Timor-Leste, and some states of India Elsewhere in the region countries are categorized as having low to moderate transmission except Australia, Japan, New Zealand, Singapore and the Pacific island nations east of Vanuatu, which are all malaria free.It is important to note that there are local variations within countries. Countries considered to have low levels of malaria may have localized foci with intense transmission and ‘malarious’ countries may have large areas that are malaria free. The CDC Malaria Map Application allows users to zoom into countries to find information on areas of greatest risk within the country as well as specific information by province.
Transmission patterns are determined by a broad range of factors. Behaviour may vary very considerably from one vector species to another. Host preferences (animal or human), preferred biting time, resting behaviour are a few of the factors that determine the capacity of a mosquito species to transmit malaria and their vulnerability to control measures. Meteorological factors such as differences in rainfall, humidity and temperature (also linked to altitude) determine the geographical range of different mosquito species and so influence transmission patterns. Land use, types of housing as well as insecticide and drug resistance levels also affect disease patterns. The epidemiology of malaria in the Asia-Pacific region is particularly complex, reflecting the diversity of habitats, vector species and human behaviours. Where transmission occurs determines who is at risk of contracting malaria. For example urban malaria transmission may put most of a community at risk (e.g. Honiara in the Solomon Islands), whereas malaria transmission restricted to forests may result in the majority of cases being seen in forest workers (e.g. areas along the Thai-Cambodia border).
In areas with moderate to high transmission rates, malaria may be stable i.e. year round with seasonal peaks. In areas of low to moderate transmission malaria transmission is often unstable and it is common to have malaria outbreaks, potentially leading to epidemics if the outbreak response is absent, late or otherwise ineffective.
Mixed malaria infections, particularly of falciparum and vivax, are common; this has implications for diagnostic and treatment approaches.
Click here to access links that will guide you to find detailed information on malaria, entomology and control approaches by country.
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