Pharmaceuticals, improvement in healthcare delivery systems, veterinary care, and poverty-alleviation remedies are part of an overall strategy for addressing neglected tropical diseases.
The World Health Organization (WHO) issued in October 2010 a report, Working to Overcome the Global Impact of Neglected Tropical Diseases, to outline the progress and strategy to address the problem of tropical diseases. The report is the first time WHO has specifically issued a report on neglected tropical diseases, which typically have low visibility in the developed world as they tend to affect specific populations or areas in impoverished and developing nations
“Neglected tropical diseases have had their breeding grounds in the places left furthest behind by socioeconomic progress, where substandard housing, lack of access to safe water and sanitation, filthy environments, and abundant insects and other vectors contribute to the efficient transmission of infection,” said Margaret Chan, WHO director, in the report. Chan said developing and distributing treatments for neglected tropical diseases is important not only from a global health perspective but also as an antipoverty initiative as global health initiatives are incorporated in the United Nations’ Millennium Development Goals, a set of eight antipoverty goals. “Efforts to control neglected tropical diseases constitute a pro-poor strategy on a grand scale,” said Chan in the report. “The logic has changed: instead of waiting for these diseases to gradually disappear as countries develop and living conditions improve, a deliberate effort to make them disappear is now viewed as a route to poverty alleviation that can itself spur socioeconomic development.”
Defining the problem
Neglected tropical diseases are a group of communicable diseases that thrive in impoverished settings, according to the WHO report. Of the world’s poorest 2.7 billion people (defined as those who live on less than $2.00 per day), more than 1 billion are affected by one or more neglected tropical diseases. The WHO report focuses of 17 tropical diseases: dengue fever, rabies, trachoma, Buruli ulcer, endemic treponematoses, leprosy, Chagas disease, sleeping sickness, leishmaniasis, cysticercosis, guinea-worm disease, echinococcosis, foodborne trematode infections, elephantiasis, river blindness, bilharziasis, and intestinal parasitic worms. Most of the diseases are parasitic diseases caused by various protozoan and helminth parasites.
WHO recommends five public-health strategies for prevention and control of neglected diseases:
• Expansion of preventive chemotherapy. Preventive chemotherapy is used to deliver anthelminithic medicines by means of a population-based approach to target more than one form of helminthiasis.
• Intensified case-detection and case management. For protozoan and bacterial diseases such as African trypanosomiasis, leishmaniasis, Chagas disease, and Buruli ulcer, the new focus is on better access to specialized care through improved case detection and decentralized clinical management as a means to prevent and reduce mortality and interrupt transmission.
• Improved vector control. Integrated vector management seeks to combine different interventions within several sectors, including health, agriculture, and the environment. The goal is to improve the efficacy of cost-effective, ecological sound, and sustainable disease-control measures against vector-borne neglected tropical diseases.
• Appropriate veterinary public health measures. Several neglected tropical diseases come from animal hosts. These diseases include cysticercosis, echinococcosis, foodborne trematode infections, and rabies.
• Provision of safe water, sanitation, and hygiene.
WHO also recommends three other strategies for the prevention and management of neglected tropical diseases. These recommendations include promoting development to break the cycle of disease and poverty, foster health security of individuals and livestock, and strengthen health systems in national health initiatives.
These strategies are part of an overall approach to address neglected tropical diseases through a broader integrated plan to combat poverty and disease. WHO says that neglected tropical diseases can be controlled if three requirements are met:
• Attention and action are given to the health needs of populations affected by neglected tropical disease rather than to their individual disease
• Interventions to deliver treatments are integrated with control measures
• Evidence-based advocacy is deployed to generate resources for control from the international community.
Pharmaceutical industry participation
Private-sector support through research, development, and direct financial contributions are part of the solution to addressing the problem of neglected tropical diseases, according to the WHO report. In issuing the report, WHO identified the contributions made by the pharmaceutical industry, including several recently announced efforts by pharmaceutical companies. These initiatives include:
• Novartis (Basel, Switzerland) renewed its commitment to donate an unlimited supply of multidrug therapy and loose clofazimine for leprosy and its complications
• GlaxoSmithKline (London) announced a new five-year commitment to expand its donation of albendazole through WHO, in addition to their current donation for lymphatic filariasis to treat school-age children for soil-transmitted helminthiases in Africa. The commitment includes 400 million doses per year for this purpose.
• sanofi-aventis (Paris) agreed to renew its support for the WHO program to eliminate sleeping sickness and its support for treatments for Buruli ulcer, Chagas disease, and leishmaniasis for the next five years.
• Bayer (Leverkusen, Germany) started discussions with WHO on how to evolve its current commitment to fight sleeping sickness and Chagas disease.
• Eisai (Tokyo) committed to work toward the global elimination of lymphatic filariasis by providing diethylcarbamazine
• Johnson & Johnson (New Brunswick, NJ) announced it is expanding its donation of mebendazole to supply up to 200 million treatments per year for treatment of intestinal worms in children.
Following the WHO report, several companies and associations announced further efforts targeted for treating neglected tropical diseases. In November 2011, GlaxoSmithKline (GSK, London) and the Oswald Cruz Foundation (Fiocruz), a research institute based in Brazil, formed a collaboration to share research and expertise for drugs to treat malaria, tuberculosis, and leishmaniasis, with initial research prioritized for drugs to treat Chagas disease and leishmaniasis. Merck & Co. pledged $150,000 to the Carter Center, a nonprofit organization founded by former President Jimmy Carter, for its sponsorship of the Onchocerciasis Elimination Program of the Americas (OPEA), an initiative to eliminate river blindness. The center’s OPEA works with Merck, the Merck Mectizan Donation Program, the Pan American Health Organization (PAHO), the US Centers for Disease Control and Prevention, the Loins Club International Foundation, and the Bill and Melinda Gates Foundation as well as other academic and other organizations to eliminate river blindness. Merck’s funding will be in the form of a challenge grant, whereby the Carter Center will raise an additional $150,000 in matching funds. In 2008, PAHO passed a resolution calling for river blindness to be eliminated in Latin America by 2012 and for official certification of elimination by 2015. The Carter Center assists national ministries of health in six Latin American countries (Brazil, Colombia, Ecuador, Guatemala, Mexico, and Venzuela) to conduct health education and distribute Merck’s Mectizan (ivermectin), a drug to treat river blindness. Also, the Bill and Melinda Gates Foundation pledged $50 million over five year to the Innovative Vector Control Consortium, a nonprofit product-development partnership, for developing insecticides for improved control of mosquitoes and other insects that transmit dengue, other neglected tropical diseases, and malaria.
In its report, WHO summarized these contributions and others by the pharmaceutical industry for combating tropical neglected diseases. By active ingredients, these contributions are:
Albendazole: unlimited supply as needed from GlaxoSmithKline for lymphatic filariasis
Azithromycin: unlimited quantity from Pfizer (New York) in the context of SAFE strategy (Surgery, Antibiotic treatment, Facial cleanliness and Environmental improvement)
Eflornithine: unlimited quantity until 2012 from sanofi-aventis for human African trypanosomiasis
Ivermectin: unlimited supply as long as needed from Merck & Co. for lymphatic filariasis and onchocerciasis
Multidrug therapy (rifampicin, clofazimine and dapsone in blister packs) and loose clofazimine: unlimited supply for as long as needed for leprosy and its complications from Novartis
Mebendazole: 50 million tablets annually from Johnson & Johnson for soil-transmitted helminthiases-control program for children. From 2011, the donation will increase to 200 million annually
Melarsoprol: Unlimited quantity until 2012 from sanofi-aventis for treating human African trypanosomiasis
Nifurtimox: 900,000 tablets (120 mg) per year by 2014 from Bayer for treating Chagas disease and human African trypanosomiasis
Pentamidine: unlimited quantity by 2012 from sanofi aventis for treating human African trypanosomiasis
Praziquantel: 200 million tablets during 2008-2017 from Merck KGaA (Darmstadt, Germany) for treating schistosomiasis
Suramin: unlimited quantity by 2012 fro Bayer for treating human African trypanosomiasis
Triclabendazole: From Novartis for treating fasciollasis
Successes and challenges
The WHO report identified successes in combating neglected tropical diseases and future challenges. Some key positive achieved and predicted results are:
• Treatment with preventive chemotherapy reached 670 million people in 2008
• Dracunculiasis, also called guinea worm disease, will be the first disease eradicated not by a vaccine, but by health education and behavioral change
• Reported cases of sleeping sickness currently have dropped to their lowest level in 50 years
• Lymphatic filariasis is targeted for elimination as a public health problem by 2020.
The report also recognizes the challenges that lie ahead and the opportunities to alleviate the suffering of people in disease-endemic countries. For example, delivery systems need to be strengthened. "The use of the primary school platform to treat millions of children for schistosomiasis and helminthiasis in Africa is a perfect example. It provides opportunities to broader health education, thereby ensuring healthier future generations," said Lorenzo Savioli, director of the WHO Department of Control of Neglected Tropical Diseases, in an Oct. 14, 2010 press release.
The report finds that better coordination is needed with veterinary public health as an essential element of zoonotic disease control. For example, every year, tens of thousands of human deaths occur from rabies, usually contracted from dogs. An estimated 95% of cases occur in Asia and Africa and up to 60% of cases are in children under 15 years of age. The report also said that public health systems must also respond to changing disease patterns resulting from climate change and environmental factors, which may cause the wider spread or resurgence of some diseases. Dengue, for example, has emerged as one of the fastest-growing disease burdens in the world; today, cases are reported in many regions formerly free of the disease. Sustained environmental and vector management remain key approaches for the prevention of vector-borne neglected tropical diseases, said the report.