Malaria in Assam: A public health challenge

 By Dr. Dharmakanta Kumbhakar

Assam is a highly malarious area of the country. Most areas in Assam are considered high risk for acquiring malaria. There is a heavy parasite load in the local population in most parts of the state. Assam alone, with only 2.6% of the country's population, contributes more than 5% of the total malaria cases and over 20% of the total malaria deaths of the country annually. Malaria is responsible for high morbidity and mortality in the state. Nearly 30 to 40% of outdoor cases are due to malaria during the peak transmission period (May to September) corresponding to the rainy months. Malaria contributes to 3.60% to 7% of all hospital admissions in Assam. Both Plasmodium falciparum and P. vivax occur in abundance, but P. falciparum (the killer parasite) accounts for more than 60% of cases. Disease outbreaks characterized by enhanced morbidity are annual events that take heavy toll on human lives amidst public chaos and panic.  

Even a century after the discovery of malaria transmission through mosquitoes in India by Sir, Rold Ross in 1897, malaria continues to be one of Assam's leading pubic health problems. Rising number of  P.falciparum parasite that often lead to fatality combined with increasing resistant to chloroquine, iccessibility and remoteness of the severely malaria-prone pockets, favourable environment of the state for both mosquito proliferation and active malaria transmission, poverty and other factors have made the citizens of the state  more vulnerable. Resistance to chloroquine was first detected in Assam in 1973 in Manja PHC of Karbi Anglong district. Today, all the 11 PHCs of the district have been declared as resistance to chloroquine.  Most districts of the state are malaria endemic and many pockets in forest, forest-fringe and foothill villages located along the inter-country/inter-state border are vulnerable to focal outbreaks. In a study conducted by this writer, malaria cases have been registered in all the districts of Assam. But, some districts including Karbi Anglong, gaon, NC Hills (Dima Hasao), Hailakandi, Kokrajhar, Goalpara and Baksa have been identified as more vulnerable. Based on the annual parasite incidence (API), defined as number of confirmed cases per thousand of population, ten districts reported less than two cases. For all other districts (44% of total population), the API was more than two. Amongst the districts, the hill districts of Karbi Anglong and Dima Hasao were the worst affected, reporting an API more than12. These are the districts having more than one inter-state border and a higher concentration of tribal aborigines (more than 50%). Comparatively, the districts of lower Assam, particularly Kokrajhar, Darrang, Goalpara and Hailakandi were more malaria-prone with an API in the range of 4-11, than upper Assam where the districts of Dibrugarh, Sibsagar, Tinsukia and Jorhat were affected the least reporting the lowest API (0.02-0.1). Areas with intertiol and inter-state border in the state were more prone to malaria. Among the two intertiol borders, the Indo-Bhutan had as many six districts and contributed more cases and deaths in comparison to the three districts sharing their borders with Bangladesh. Malaria is now establishing its foothold in the  bordering districts previously free of the disease, such as Lakhimpur, Jorhat and Tinsukia owing to the deforestation and population migration/new settlements in the reserve forest areas, reporting increased morbidity and mortality.

It is evident that malaria remains endemic in the state despite the intervention strategies being in force ever since the establishment of the tiol Malaria Control Programme in 1953. Malaria control in Assam faces many challenges. Here, malaria transmission is perennial and persistent with the seasol peak during April-September corresponding to the months of rainfall. The region is highly receptive to malaria transmission due to excessive and prolonged rainfall promoting vector breeding and longevity due to high humidity (60-90%) and warmer climates (22-33 degree C) for most of the year. Tropical rain-forest rich in wild life including reserve forests and sanctuaries, interspersed with valleys, hills and settlements make the region highly receptive for maintaining perennial malaria transmission. As many as 130 species of mosquitoes including 37 anophelines and 93 culicines belonging to 12 genera have been recorded in the region. There is persistence of malaria in Assam due to very efficient vectors, An. minimus (the perennial species), An. dirus (the monsoon species) and An. fluviatilis (the winter species), the latter acts as a relay transmitter in the foothill areas. Schedule tribes and scheduled castes of the state (comprising 12.8% and 7.4% of Assam's total population respectively) suffer from neglect and high levels of poverty; about 30-40% population of Assam lives below the poverty line which is a big driver for maintaining perennial transmission. Close contact and free movement of people in bordering areas make these pockets more vulnerable to malaria.

Healthcare facilities in the state tend to be located in urban areas; consequently, treatment access is poorly addressed by the health systems in the periphery where it is needed most. Vast areas inundated with floods annually become iccessible settlements that remain cut off during the rainy season which happens to be the peak transmission season. Poor and scattered houses, mostly made of mud and bamboos, provide the ideal indoor resting places for mosquitoes.

There are many more administrative and socio-economic problems hampering successful malaria control in Assam. Until malaria vaccines become available, we have to rely on old, traditiol interventions with emphasis on reducing man-mosquito contact. Information, Education and Communication (IEC) should become a continuing activity to help strengthen the process of early case detection and prompt treatment (EDPT), use and care of bed nets (LLINs/treated nets), eliciting people's participation in vector control, and encouraging inter- and intra- sectoral coordition.

Malaria constitutes one of the most important causes of economic misfortune, engendering poverty which lower the physical and intellectual standards of the state and hamper prosperity and economic progress in every way. Accelerated economic and infrastructural development is urgently needed to improve this situation. In the face of rapid population increase, there is a need for increased allocation of resources for control interventions beginning with the below poverty line families/high-risk population groups. The need of the hour is the commitment for continued increased allocation of resources and its judicious application in time and place ensuring equity in health care services.