The Malaria Problem in South-East Asia Region

Disease Burden in SEA Region

"Malaria is a major public heath problem in the South-East Asia Region. Out of 11 countries of the Region 10 countries are malaria endemic (Map1 [PDF 1 MB]). In Maldives, there is no indigenous transmission since 1984. Malaria reemerged in DPRK in 1997-98. Around 40% of the global population at risk of malaria resides in SEA Region and accounts for 15% of the global reported confirmed cases and around 2.7% of the global mortality due to malaria (Fig.1)."

Fig. 1 :Global Malaria Burden

Source : World Malaria Report, 2011

Malaria causes about 2414 death a day, over 90% of which are in Sub-Sahara Africa. It is both a disease of poverty and a cause of poverty slowing economic growth by 1.3% per year in endemic areas. WHO estimates that globally 33.96 million DALYs lost due to malaria in which SEA Region contributes around 1.34 million (Source: The global burden of disease: 2004 update).

Malaria is an enormous health and development problem in the SEA Region as 1 322 million people are at risk of malaria. The social, cultural and economic dimensions in terms of disproportionate impact on the poor, the associated loss of wages and productivity both at the micro and macro levels are enormous. The disease is deeply rooted in the poor communities affecting national development and takes away major share of the health budgets. In the WHO South East Asia Region, Maldives is the only country free from indigenous transmission since 1984. Malaria cases have sharply declined in Bhutan, DPR Korea, Nepal and Sri Lanka. Malaria re-emerged in DPR Korea in 1997-98, but the situation has been brought under effective control. Map 1 gives malaria endemicity levels in SEA Region in 2010 i.e. low (API <1.0), moderate (API 1.0-10.0), High (API >10.0).

Malaria situation in forest and forest related areas remains serious problem due to highly efficient vectors, multiple-vector transmission, prolonged transmission season, and drug-resistant P. falciparum malaria combined with large scale and uncontrolled population movement (map2, tab1). Forest related malaria constitutes about 40% of total malaria cases of total malaria cases and about 60% of the total Pf cases in the Region. As forests are becoming increasingly accessible due to the exploitation of their natural resources, very often such population movements result in epidemics of malaria in such areas.

The malaria situation in the Region remains highly dynamic and evolving, and likely to be further aggravated by climate change. There is an evidence to show that warming of the earth’s temperature and increasing precipitation will hasten maturation of the parasite in mosquitoes, increase the biting frequency and create conditions more conducive to mosquito breeding. Climate change is expected to worsen in the future, both in frequency and intensity, as also the health consequences. This will disproportionately affect the poor and marginalized sections of society, particularly those living in remote forest areas such as tribal populations.

An estimated 1 322 million people or 76% of the total population of SEA Region are at risk of malaria. Out of which around 29% population at moderate to high risk of malaria, 71% are at low risk of malaria, whereas remaining 24% of population is free from malaria (Tab 2 [PDF 15 KB]). About 93% of the population of moderate to high risk of malaria in SEA Region are living in Bangladesh, India, Indonesia, Myanmar, Thailand and Timor Leste, and contributing more than 95% of confirmed malaria cases and deaths in the Region. Among the population living in malaria endemic areas, infants, young children and pregnant women have been identified as high risk groups. Other groups of people which constitute high malaria risk are mobile population particularly those engaged in forest-related economy, gem-mining, fishing, industrial and engaged in road construction work. In some countries, ethnic minorities, refugees, displaced persons, tourists and pilgrims also constitute high risk group.

In SEA Region between 2000-2010, reported malaria incidence remained around 2.30 – 3.08 million cases and deaths between 2 423 - 6 978 annually (Fig. 2 [PDF 370 KB]). Similarly, the other malaria-metric parameters viz. annual blood slide examination rate (ABER%), slide positivity Rate (SPR%) and Pf% were recorded between 6.5% - 8.4%, 2.1% - 3.2% and 45% - 61% respectively in the Region, Also, the malaria Incidence per thousand population at risk (API) during the said period was recorded between 1.7 – 2.2 where as malaria mortality per hundred thousand population was remained between 0.16 -0.51. Bhutan, DPR Korea, Sri Lanka and Thailand showed significant reduction in malaria morbidity were as in the remaining countries of the Region, no appreciable change recorded in the malaria morbidity. However, except India and Indonesia, it is worth noticing that malaria mortality declined in all countries presumably due to use of ACT. The highest reduction in mortality was recorded in Sri Lanka followed by Bangladesh, Thailand and Bhutan respectively.

During 2010, the confirmed malaria cases and malaria deaths were reported as 2.3 million and 2 426 respectively in the Region, whereas the WHO /HQ estimated malaria cases and deaths were around 28-41 million and 49000 respectively (Source: World Malaria Report, 2010). The highest number of confirmed cases were reported from India (1 495 817) followed by Myanmar (420 808) and Indonesia (229 819), whereas the lowest number of cases were reported from Bhutan (520) followed by Sri Lanka (684) and Nepal (4 075) . Similarly, the highest number of deaths were reported from India (1023) followed by Myanmar (788) and Indonesia (432) and lowest number of deaths were reported from Sri Lanka (0) followed by Bhutan (2) and Nepal (6) For details see Tab.3 [PDF 15 KB] , Fig. 3 [PDF 159 KB] and Fig 4 [PDF 143 KB].

The highest Annual Parasite Incidence (API) per 1 000 population at risk of malaria was reported from Timor Leste (41.9 API) followed by Myanmar (11.2 API) and Indonesia (2.0 API) whereas the lowest incidence was reported from Sri Lanka (0.14 API) followed by Nepal (0.19 API) and DPRK (0.90 API). It may be noted that due to change in definition, the population at risk of malaria in the SEA region has changed considerably. This has affected the morbidity (API) and mortality figures to some extent in 2010. The other malaria-metric indicators like, Pf% was highest in Bangladesh (93%) followed by Myanmar (92%) and Timor Leste (75%) whereas lowest in Sri Lanka (2.5%), followed by Nepal (25.4%) and Bhutan (33.7%) respectively except DPRK where only P. vivax exist. The highest positivity rate was reported from DPRK (53.8%) followed by Myanmar (41.9%) and Indonesia (25.4%), whereas the lowest SPR was reported from Sri Lanka (0.07%) followed by Bhutan (0.93%) and India (1.41%) respectively (Tab. 3). Although P. falciparum incidence remained stable, but its percentage increased from 12.93% in 1977 to more than 60% in 2010 in the Region (Fig. 5 [PDF 298 KB]).The increasing proportion of P. falciparum may be the result of rising trend of drug resistance, presumptive treatment with chloroquine suppressing P. vivax, and the use of mono-valent RDT (for Pf only) in the Region. It is worth mentioning that increase in confirmed cases in the Region from last 2-3 years is basically by increased case detection in the countries specially in Indonesia, Myanmar, Bangladesh and India using donor’s fund. Sri Lanka and DPRK now entered in to malaria pre-elimination phase where as rest of the countries are still in control phase

Further, during 2000-2010, the confirmed malaria cases and malaria deaths declined by 25.3% and 57.6% respectively in SEA Region. Out of 10 endemic countries of the Region, confirmed cases declined in 7 countries. 5 countries registered more than 50% decline namely, Sri Lanka (99.7%), Bhutan (91.2%), DPRK (81.7%), Thailand (60.2%), Nepal (59.1%) where as India registered a decline of 26.4% and Indonesia around 6.4% ( Fig 6 [PDF 218 KB]). In Bangladesh confirmed cases marginally increased (by 0.5%) where as in Myanmar, confirmed cased increased by 245%. (The data for Timor Leste could not be compared due to non-availability of base year data). The increase in confirmed cases mainly in Myanmar, Bangladesh and very little decline in Indonesia was mainly due enhanced case finding activities employed through donor’s driven funds. Similarly, the reported malaria deaths declined in all countries of the Region except in India, Nepal and Timor Leste. In India, it has increased by 9% where as in remaining two countries, the base year data is not available hence could not be compared. The highest decline in reported malaria deaths was registered by Sri Lanka (100%) followed by Bangladesh (92.4%), Bhutan (86.7%) Myanmar (71.4%), Indonesia (48.1%), Thailand (88.8%) and India (18.7%). In India, the reported malaria deaths not declined impressively mainly due to better malaria mortality reporting in programme. There was no change in the status of DPRK as P. vivax is not a killer parasite. Further, Timor Leste could not be compared due to non availability of data.

Chloroquine resistant P. falciparum is reported from all endemic countries (except DPR Korea); nearly 400 million people live in areas with risk of contracting drug resistant malaria Sulfadoxin-pyrimethamine resistance is also reported from all endemic countries except Sri Lanka and DPR Korea with an estimated 140 million population at risk. Deteriorating epidemiological indices are associated with drug resistance and operational problems. Multidrug resistant P. falciparum is highly prevalent on the Thai-Cambodia and Thai-Myanmar border areas. Even response to ACTs have reduced in Thai-Combodia border (Map3 [PDF 107 KB]

Frequent epidemics are being observed by Member Countries. However, Bangladesh, Bhutan, Nepal and Sri Lanka have not reported any major epidemic since last 3-5 years. Vector control through Indoor Residual Spray in all the countries and larvivorous fish in India, Indonesia, Myanmar, Sri Lanka and Thailand is being observed. Epidemic preparedness and surveillance are key control strategies in all countries. All countries have start using ITNs. Bangladesh and Bhutan has made good progress in it and successfully able to reduce cases by up scaled ITN coverage.