Key Challenges of Malaria Control in SEA Region

Drug resistance

Over the last five decades, Southeast Asia (SEA) has been the epicenter for the evolution and spread of drug resistance to all important classes of antimalarials. The highest rates of anti-malarial drug resistance is reprted from this paert of the world. Chloroquine (CQ) and sulfadoxin-pyrimethamine (SP) resistance by P. falciparum are reported from almost all countries (averaging ~40% for CQ and between 20 and 40% for SP ). Multi-drug resistant P. falciparum, which includes decreased sensitivity (if not resistance) to artemisinin, is found in Western Cambodia bordering Thailand, and north-eastern Myanmar bordering Thailand. It manifested by a marked slowing of parasite clearance in Pailin, in Cambodia. No molecular markers in genes were associated with resistance against other antimalarials or artemisinin resistance (PfMDR, PfCRT, and PfSERCA).

Chloroquine-resistant P. vivax is found in India, Indonesia ( Papua province) and Myanmar. The potential expansion of artemisinin-resistant P. falciparum from the Mekong sub-region to other parts of Asia and Africa remains a global threat. The rapid strengthening of monitoring systems for drug resistance is therefore extremely critical in Asia. The use of artemisinin mono-therapies should be banned as recommended by the WHO to avoid resistance to ACTs. A regional surveillance network has been designed to foster collaboration between countries in monitoring malaria drug resistance.

Insecticide resistance

. Insecticide resistance is a major issue in the SEA Region. In India, resistance to almost all types of insecticides have been reported; in the Mekong region, insecticide resistance was reported from several countries and resistance occurring even in non-endemic areas needs to be monitored because of the risk of vector migration to endemic regions . Sri Lanka has adopted the rotational use of insecticides as residual sprays to delay. the emergence of resistance to insecticides. There is a need for strong processes of insecticide resistance monitoring, quality assurance of products and resistance management strategies.

Difficulty in control and elimination of P. vivax

P. vivax transmission is widespread in SEA Region. Around 50% of the confirmed malaria cases are P. vivax cases. Several elements make it difficult to control: it has a unique biology (generation of hypnzoites in the liver stage) with a large prevalence of asymptomatic cases among semi-immune populations, it responds differently to anti-malarials than P. falciparum and research in the past years on P. vivax has been poorly funded leading to few tools and approaches for control, the current tools for radical cure (14-days of primaquine) poses a challenge of adherence to treatment and in places where P. vivax transmission occurs, mixed infections with P. falciparum are common. Basic and operational research on P. vivax needs to be expanded and strong BCC programs are required to ensure adherence to treatments. In addition, regional cooperation networks could be created to share practices on the control of P. vivax malaria.

Forest malaria and migrant populations

Some major forest regions in Asia are malaria endemic. In these areas where mosquitoes bite and rest outdoors, it is difficult to use traditional vector control interventions (LLINs, IRS). Some innovations are being tested such as insecticide-treated blankets or hammocks. The availability of new tools is crucial to achieving universal coverage. Furthermore, in many areas of the region, a significant part of the malaria burden is borne by isolated ethnic groups and migrant forest workers living in difficult to access trans-border areas (as is the case on the Thai-Myanmar and Thai-Cambodian borders) Operational research and regional collaborations with other initiatives focused on these populations (e.g. labor, migration, HIV/AIDS, etc) may be successful in developing comprehensive approaches that include malaria. In order to reach these isolated populations, integration with other health services (such as immunization) needs to be strengthened and community health management could be promoted, with the establishment of networks of community heath workers.

Cross-Border Malaria

In SEA Region, malaria is an important disease along the international borders. This is a perennial problem arising out of uncontrolled migration, poor health delivery system and lack of coordination along the border districts. Therefore malaria flourishes along the international borders and often transported to relatively low transmission areas. In particular spread of drug resistant malaria causes serious concern as it can multiply rapidly in ecosystems lacking malaria information on drug resistance and correct interventions are often wanting. Studies have revealed that the incidence of malaria is relatively high along the border districts than in the interior regions. Border areas are also very extensive requiring special efforts on sustained basis to bring the disease under control.

Cross-border malaria in Terai region of Nepal and India (Uttar Pradesh, Bihar, and West Bengal) is spread in approximately 900 kms area where drug resistant P. falciparum strains are encountered on both sides of the border. Similarly, along the India-Bangladesh, India-Bhutan, India–Myanmar, India-Nepal, Bangladesh-Myanmar and Thailand-Myanmar international borders malaria is a big problem.

Malaria outbreaks/epidemics

Malaria outbreaks/ epidemics are common during the rainy season. This is because malaria in SEA Region is unstable, although in small population in the deep jungles it is stable. Outbreaks involve a village or a group of villages in a PHC but epidemics generally cover the entire district or an ecotype. These are invariably the results of neglect in surveillance and the lack of adequate treatment. In the outbreak areas transmission may not be intense but these populations remain at high risk of repeated outbreaks and upsurge of drug resistant malaria. Malaria outbreaks in SEA Region suggest that conditions for the occurrence of epidemics are very favourable in many countries of the Region and prevention of outbreaks require sustained vigilance and preparedness to combat deteriorating malaria situation.

Malaria outbreaks and deaths remain a common feature in unstable malaria endemic areas in the Region. A combination of determinants contributes to conditions favorable for accelerated transmission. Often outbreaks go unreported due to breakdown in surveillance. There are many other factors that may or may not combine with other determinants in precipitating outbreaks. Investigations have revealed some commonly encountered problems created in the populations affected by the malaria upsurge such as the refugee settlements, natural disasters, political unrest, population migration, tropical aggregation of labor, deforestation, irrigation projects for intensive agriculture, international borders, etc., shortage of drugs, insecticides, equipment; weak or non-existent laboratory services, and poor health infrastructure particularly in the remote and inaccessible regions etc. Major epidemics have been averted and controlled by mobilizing rapid response teams in the endemic countries. Epidemics cover large territories when non-immune or partially immune populations lack malaria control interventions and vector inoculation rates remain high.

Major malaria epidemics have been averted (Bangladesh, Myanmar, India, Indonesia, Thailand) and malaria situation has improved in many countries (Bhutan, Nepal, DPR Korea and Sri Lanka). Countries of the Region have strengthened their health infrastructure, implemented the revised malaria control strategy, continue to develop and nurture strong bonds of partnership, deployment of funds from GFATM and other UN and partner organizations in fighting malaria with newer technologies e.g. early differential diagnosis (strengthening microscopy, RDT); prompt and complete treatment (ACT for Pf), preventive vector control (IRS,ITN/LLIN), and investing in malaria R & D.

Inadequacy of Trained Manpower

Many malaria control programs lack sufficient human resources to successfully run their programs. This is due to a variety of factors: high attrition rates of skilled staff, difficulty filling positions, competing demands with other programs, and the unwillingness of health providers to be stationed in remote areas. In particular, countries report a dearth of technical experts (such as entomologists or M&E specialists), staff for the delivery of prevention and case management interventions (skilled teams for IRS), and lab workers in health facilities to conduct microscopy. There is a strong need to increase trainings for new staff, especially for areas where there is a high demand (Bhutan, Nepal, Timor-Leste, etc). A training network (ACTMalaria) has been established in 12 Asian countries to provide collaborative training and improve communications on malaria affecting common borders. Besides, rapid decentralization in some countries has led to high need of skills (especially program management) at the regional and local level, which are missing. Capacity building is required at the national, regional and local level.

Poor quality of drug and other commodities

Due to high cost of effective anti-malarial drugs such as ACTs and the strong manufacturing capabilities of companies in the region, fake and substandard drugs are prevalent, especially in the Mekong region. In 2001, studies showed that more than 30% of Artesunate collected from international borders of Mekong countries was fake . The issue of poor quality drugs is even more complicated in countries where most of the drugs are accessed from the private sector or from drug peddlers. Similarly, concerns have been raised on the quality of LLINs, insecticides used for IRS, or RDTs, especially when districts have their own procurement mechanisms. Quality control processes for all interventions need to be in place and regional cooperation should be encourage on this issue

Difficulty to maintain long term malaria funding and political support

Maintaining funding and political support for malaria control efforts especially in areas where successful control has led to low burden and pre-elimination stage is critical. Increased national funding can be considered as a sustainability factor especially in place where donor support is limited or declining because these countries are not considered as priority areas any more. In-country and international advocacy efforts are required to maintain political and financial support