Access this article online Editorial Website: www.searo.who.int/ publications/journals/seajph DOI: 10.4103/2224-3151.115828 -borne diseases in South-East Asia: Quick Response Code: burdens and key challenges to be addressed

WORLD HEALTH DAY AND fitting that the theme of World Health Day 2014 focuses on ITS SIGNIFICANCE vector-borne diseases.1 World Health Day is celebrated on 7 April every year to mark the Many vector-borne diseases are prevalent in the South- anniversary of the founding of the World Health Organization East Asia Region. These include, among others, mosquito- (WHO) in 1948. Each year a theme is selected that highlights borne diseases (e.g. , dengue, , Japanese a priority area of . It provides an opportunity for encephalitis, lymphatic filariasis), sandfly-borne disease (kala- individuals in every community to get involved in activities azar) and snail-transmitted disease (e.g. schistosomiasis). The that can lead to better health. World Health Day 2014 focuses highly infectious and fatal tick borne viral diseases, Kyasanur on vector-borne disease with the following aims: (a) families forest disease and Crimean Congo hemorrhagic fever are living in areas where diseases are transmitted by vectors know present in India6 but not much is known about these in the how to protect themselves; (b) travellers know how to protect Region probably due to poor surveillance and very limited themselves from vectors and vector-borne diseases; (c) in diagnostic facilities to detect it. countries where vector-borne diseases are a public-health problem, ministries of health put in place measures to improve Malaria is endemic in all countries in the Region except the protection of their populations; and (d) in countries where Maldives, which has been malaria-free since 1984. WHO vector-borne diseases are an emerging threat, health authorities estimated that there were 27 million cases and 42 000 deaths due to malaria in 2012 in the Region, where around 1.4 billion work with environmental and other authorities locally and in 5 neighbouring countries to improve integrated surveillance of people are at risk. In India, the total economic burden from vectors and to take measures to prevent their proliferation.1 malaria could be around $1940 million, mainly from lost earnings (75%) while 24 percent comes from treatment costs.7 This special issue of the WHO South-East Asia Journal of Public Health focusing on vector-borne diseases is one of the Of the 1.3 billion people globally at risk of lymphatic filariasis, highlights of World Health Day 2014 activities in the WHO 871 million reside in the South-East Asia Region, of whom Regional Office for South-East Asia. 297 million (34%) are children. Of the 120 million infected people globally, 60 million are in the Region. The Region thus accounts for about 65% of the global population at risk and VECTOR-BORNE DISEASES 50% of the infected people.8 About 147 million people in three countries (Bangladesh, India and Nepal) are at risk of kala- Vectors are living organisms that can transmit infectious azar, mainly the poor and marginalized populations. Recently, diseases between humans or from animals to humans. a small focus of kala-azar has been identified in Bhutan. Mosquitoes are the best known disease vector. Others include Estimates indicate about 100 000 cases of kala-azar per year in ticks, flies, sandflies, fleas, triatomine bugs and some freshwater this Region.9 Schistosomiasis in the Region is limited to small aquatic snails.2 areas in two districts in Indonesia where the number of school- age children requiring preventive chemotherapy in 2012 was Vector-borne diseases account for more than 17% of all only 2998 compared with 114 348 387 globally, mainly in infectious diseases, causing more than 1 million deaths Africa.10 annually.2 Yet, five vector-borne diseases – Chagas disease, dengue/severe dengue, human African trypanosomiasis, The South-East Asia Region has become hyperendemic with leishmaniasis, lymphatic filariasis and schistosomiasis – are regular reporting of dengue cases since 2000. The maximum among the 17 neglected tropical diseases.3 The incidence of number of cases (355 525) and deaths (1982) were recorded dengue has increased 30-fold over the last 50 years. Up to during 2010.11 In 2012, a total of 257 204 cases and 1229 50–100 million are now estimated to occur annually deaths were reported from the Region.12 Chikungunya occurs in over 100 endemic countries, putting almost half of the in Africa, Asia and the Indian subcontinent. Human infections world’s population at risk.4 In 2012, there were an estimated in Africa have been at relatively low levels for a number of 207 million cases and an estimated 627 000 deaths due to years. A major outbreak occurred in the islands of the Indian malaria, mostly (90%) in sub-Saharan Africa.5 It is therefore Ocean in 2005 and since then, India, Indonesia, Maldives,

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Myanmar and Thailand have reported over 1.9 million cases.13 with delayed parasite clearance in patients treated with Japanese encephalitis is endemic in 24 countries in the WHO artemisinin has been identified, which could help improve South-East Asia and Western Pacific regions. It is the main global surveillance of artemisinin resistance.26 There is an cause of viral encephalitis in many countries of Asia with urgent need for all stakeholders to work together to address nearly 68 000 clinical cases every year. The case-fatality insecticide resistance and drug resistance in accordance with rate among those with encephalitis can be as high as 30%. WHO-recommended strategies.22, 27 In the Greater Mekong Permanent neurological or psychiatric sequelae can occur in Subregion, WHO is coordinating the emergency response to 30–50% of those with encephalitis. Safe and effective vaccines artemisinin resistance28 that is being implemented by ministries are available to prevent the disease. Treatment is focused on of health and nongovernmental organizations, with support relieving severe clinical signs and supporting the patient to from development partners. A recent report from Myanmar29, overcome the .14 indicates several challenges should be addressed to improve further the achievements in containing artemisinin resistance. ADDRESSING KEY CHALLENGES CONCLUSION Most vector-borne diseases have unique epidemiological features as described in some of the articles in this special issue Vector-borne diseases are major public-health problems in of the WHO South-East Asia Journal of Public Health6,15–18. the South-East Asia Region. While progress is notable, much However, most of these diseases share common socioeconomic more needs to be done to eliminate lymphatic filariasis, determinants. These include difficult access to health services; kala-aazar, schistosomiasis and malaria and to prevent re- poverty; and poor housing, sanitation and water supplies. introduction of transmission in areas freed from these diseases. Efficient, effective and sustainable prevention and control Well-coordinated multisectoral actions as well as active of vector-borne diseases requires not only the application of participation of individuals, families and the communities at biomedical tools but also interventions to address those factors risk are necessary to eliminate these diseases and to contain that are beyond the domain of the health sector. the spread of dengue, chikungunya and Japanese encephalitis. Additional tools, innovative delivery mechanisms, political Outbreaks of dengue, chikungunya and Japanese encephalitis will and sustainable financing are essential to achieve universal are becoming common, possibly related to increasing population coverage to control and, whenever feasible, eliminate vector- movement, globalization of trade and urbanization without borne diseases. World Health Day 2014 is another opportunity adequate measures to prevent vector breeding. In addition to call for action against vector-borne diseases. to effective systems for surveillance and rapid response, multisectoral collaboration and community participation are Rajesh Bhatia, Leonard Ortega, needed to prevent and control outbreaks of these diseases. A P Dash, Ahmed Jamsheed Mohamed Department of Communicable Diseases, The parasitic vector-borne diseases – kala-azar, lymphatic World Health Organization filariasis, schistosomiasis and malaria – are being targeted for Regional Office for South-East Asia, elimination at least in some countries. Some key challenges New Delhi, India to be addressed to accelerate progress towards elimination are common to these diseases. Among them is the need to scale- up further the use of existing strategies, including integrated Address for correspondence: vector management,19 and put in place innovative delivery Department of Communicable Diseases, mechanisms to help ensure that everyone at risk or with World Health Organization the disease can easily access evidence-based interventions. Regional Office for South-East Asia, Strong political will, sustainable financing and community Mahatma Gandhi Marg, New Delhi 110 002, India. participation are essential. Investments are needed to Email: [email protected] generate strategic information for decision-making, improve procurement and supply chain management and develop and maintain the right mix of expertise at different levels of the REFERENCES to reach the goal of elimination. 1. World Health Organization. World health day - 7 April 2014. Geneva: While success in malaria control is noted globally,5 including WHO, 2014. http://www.who.int/campaigns/world-health-day/2014/ in Asia Pacific,20 and in Sri Lanka21, the pathway to accelerate event/en/ - accessed 28 March 2014. malaria control towards elimination is being seriously 2. World Health Organization. World health day: protect yourself from vector-borne diseases. Geneva: WHO, 2014. http://www.who.int/ threatened by vector resistance to insecticides and parasite campaigns/world-health-day/2014/en/ - accessed 28 March 2014. resistance to drugs. Insecticide resistance is widespread; 3. World Health Organization. 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