In a monumental achievement, Bangladesh has become the first country in the world to be officially validated for having eliminated visceral leishmaniasis, commonly known as kala-azar, as a public health problem. This milestone results from dedicated efforts and collaboration among various stakeholders, including the Government of Bangladesh, the World Health Organization (WHO), the Special Programme for Research and Training in Tropical Diseases (TDR), the Government of the United Kingdom, Gilead Sciences, Inc., the Bill & Melinda Gates Foundation, the International Centre for Diarrhoeal Disease Research, Bangladesh, and other partners in the WHO South-East Asia Region.
Kala-azar, the most severe form of leishmaniasis, is a life-threatening disease caused by Leishmania spp. parasites transmitted by infected female phlebotomine sandflies. It affects the most disadvantaged rural communities, among whom poverty, poor housing conditions, malnutrition, genetic factors, and other infectious diseases are major risk factors. Kala-azar leads to symptoms such as fever, weight loss, spleen and liver enlargement, and, if left untreated, can prove fatal in over 95% of cases.
Bangladesh was successfully validated by WHO based on the fact that the number of reported cases of visceral leishmaniasis was below 1 per 10,000 population in each of the country’s subdistricts for at least 3 consecutive years.
“Neglected tropical diseases like visceral leishmaniasis require continued national leadership, commitment and collaborative action by countries and health partners worldwide,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. “I salute the great progress made by Bangladesh, in line with WHO guidance, in eliminating visceral leishmaniasis as a public health threat”.
Collaborative elimination efforts
In 2005, Bangladesh, India, and Nepal (which together accounted for 70% of the global burden of the disease between 2004 and 2008) launched a Regional Kala-azar Elimination Initiative. These efforts were accompanied by a Regional Strategic Framework for the Elimination of Kala-azar, published in 2005 and updated in 2012, which focused on early diagnosis, complete case management, integrated vector management, effective disease surveillance, social mobilization, and operational research. This was further updated in 2022, with a focus on accelerating and sustaining the elimination status.
Over the years, research and development efforts, coordinated and financed by TDR and WHO, along with other partners, led to the introduction of innovative tools such as the rK39 rapid immunochromatographic test and improved treatment options such as miltefosine and liposomal amphotericin B. These tools played a pivotal role in enabling early detection and treatment in remote communities.
The donation of liposomal amphotericin B (AmBisome), the first-line treatment for kala-azar, by Gilead Sciences, Inc., has made an enormous contribution to accelerating the elimination program in Southeast Asia during the past decade. The drug has a high safety profile and an efficacy of over 95%. The donation has been provided through WHO since 2013.
As a result of this synergistic endeavor, new cases of kala-azar have been reduced by 95% across the Southeast Asia Region in the past 10 years, leaving only 1% of implementation units in the Indian subcontinent to achieve the target threshold for elimination as a public health problem.
In 2022, Bangladesh reported only 47 kala-azar cases, and the Southeast Asia Region reported 1069, the historic lowest number.
“Bangladesh is the first country to eliminate visceral leishmaniasis as a public health problem globally, and also the first country to eliminate two neglected tropical diseases in the same year, after the successful validation of elimination of lymphatic filariasis as a public health problem in May 2023. The collective action of the last decade has yielded remarkable results” noted Dr Ibrahima Socé Fall, Director, WHO’s Global Neglected Tropical Diseases Programme.
As part of its post-validation efforts, Bangladesh will focus on effective surveillance to sustain its hard-won status. The global distribution of visceral leishmaniasis is a significant concern, with cases reported across various geographical areas, including East Africa, which serves as another global hub for this disease. The disease burdens a substantial number of individuals worldwide.
To date, 50 countries have eliminated at least one neglected tropical disease, in line with WHO’s ambitious road map target of having 100 countries achieve this milestone by 2030. Notably, earlier this year, Bangladesh was validated for having eliminated lymphatic filariasis as a public health problem, marking a significant achievement in the fight against neglected tropical diseases.