Neglected tropical diseases

A young boy from Panama with Chagas disease. It has manifested as an acute infection with swelling of one eye (chagoma).

Neglected tropical diseases (NTDs) are a medically diverse group of tropical infections which are especially common in low-income populations in developing regions of Africa, Asia, and the Americas. They are caused by a variety of pathogens such as viruses, bacteria, protozoa and helminths. Different organizations define the set of diseases differently. In sub-Saharan Africa, the impact of these diseases as a group is comparable to malaria and tuberculosis.[1] Some of these diseases have known preventive measures or acute medical treatments which are available in the developed world but which are not universally available in poorer areas. In some cases, the treatments are relatively inexpensive. For example, the treatment for schistosomiasis is US$0.20 per child per year.[2] Nevertheless, control of neglected diseases is estimated to require funding of between US$2 billion to US$3 billion over the next five to seven years.[3]

These diseases are contrasted with the big three diseases (HIV/AIDS, tuberculosis, and malaria), which generally receive greater treatment and research funding. The neglected diseases can also make HIV/AIDS and tuberculosis more deadly.[4] However, some pharmaceutical companies have committed to donating all the drug therapies required, and mass drug administration (for example mass deworming) has been successfully accomplished in several countries.[5]

Seventeen neglected tropical diseases are prioritized by WHO. These diseases are common in 149 countries, affecting more than 1.4 billion people (including more than 500 million children)[6] and costing developing economies billions of dollars every year.[7] They resulted in 142,000 deaths in 2013—down from 204,000 deaths in 1990.[8] Of these 17, two were targeted for eradication (dracunculiasis (guinea-worm disease) by 2015 and yaws by 2020), and four for elimination (blinding trachoma, human African trypanosomiasis, leprosy and lymphatic filariasis by 2020).[7] Only 22 cases of dracunculiasis remained as of the end of 2015.[9]

List of diseases

There is some debate among the WHO, CDC, and infectious disease experts over which diseases are classified as neglected tropical diseases. Feasey, a neglected tropical disease researcher, notes 13 neglected tropical diseases: ascariasis, Buruli ulcer, Chagas disease, dracunculiasis, hookworm infection, human African trypanosomiasis, Leishmaniasis, leprosy, lymphatic filariasis, onchocerciasis, schistosomiasis, trachoma, and trichuriasis.[10] Fenwick recognizes 12 "core" neglected tropical diseases: ascariasis, Buruli ulcer, Chagas disease, dracunculiasis, human African trypanosomiasis, Leishmaniasis, leprosy, lymphatic filariasis, onchocerciasis, schistosomiasis, trachoma, and trichuriasis.[11]

These diseases result from four different classes of causative pathogens: (i) protozoa (for Chagas disease, human African trypanosomiasis, leishmaniases); (ii) bacteria (for Buruli ulcer, leprosy, trachoma, yaws), (iii) helminths or metazoan worms (for cysticercosis/taeniasis, dracunculiasis, echinococcosis, foodborne trematodiases, lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiasis); and (iv) viruses (dengue and chikungunya, rabies).

The World Health Organization recognizes the seventeen diseases below as neglected tropical diseases.[12]

Buruli ulcer

Buruli ulcer is caused by the bacterium Mycobacterium ulcerans.[13] It is related to the family of organisms that cause tuberculosis and leprosy, but Mycobacterium ulcerans produces a toxin, mycolactone, that destroys tissue.[13] The prevalence of Buruli ulcer is unknown.[10] The risk of mortality is low, although secondary infections can be lethal.[14] Morbidity takes the form of deformity, disability, and skin lesions, which can be prevented through early treatment and treated with antibiotics and surgery.[14] It is found in Africa, Asia, and Latin America.[15] The symptoms are skin swellings and lesions.[14]

Chagas disease

Chagas disease is also known as American trypanosomiasis. There are approximately 15 million people infected with Chagas Disease.[10] The chance of morbidity is higher for immuno-compromised individuals, children, and elderly, but very low if treated early.[16] Chagas disease does not kill victims rapidly, instead causing years of debilitating chronic symptoms. It is caused by a vector-borne[17] protozoa[16] and spread by contact with Trypanosoma cruzi infected feces of the triatomine (assassin) bug. The protozoan can enter the body via the bug's bite, skin breaks, or mucous membranes. Infection can result from eating infected food and coming into contact with contaminated bodily fluids.[16] Chagas disease can be prevented by avoiding insect bites through insecticide spraying, home improvement, bed nets, hygienic food, medical care, laboratory practices, and testing.[16] It can be treated etiologically or with drugs, although the drugs used to treat Chagas disease have severe side effects[16] There are two phases of Chagas disease. The acute phase is usually asymptomatic. The first symptoms are usually skin chancres, unilateral purplish orbital oedema, local lymphoadenopathies, and fever accompanied by a variety of other symptoms depending on infection site.[16] The chronic phase occurs in 30 percent of total infections[10] and can take three forms, which are asymptomatic (most prevalent), cardiac, and digestive lesions.[16] It can be diagnosed through a serological test, although the test is not very accurate.[10]

Dengue and chikungunya fever

There are 50–100 million dengue virus infections annually.[18] Dengue fever is usually not fatal, but infection with one of four serotypes can increase later susceptibility to other serotypes, resulting in a potentially fatal disease called severe dengue.[18] Dengue fever is caused by a flavivirus, and is spread mostly by the bite of the A. Aegypti mosquito.[18] No treatment for either dengue or severe dengue exists beyond palliative care.[18] The symptoms are high fever and flu-like symptoms.[18] It is found in Asia, Latin America, and Northern Australia.[18]

Chikungunya is also a viral disease, which is caused by a togavirus. The symptoms can be confused with dengue and include fever, rash, joint pain, and swelling. Chikungunya virus is transmitted by A. albopictus and A. aegypti mosquitoes. The disease mainly occurs in Africa and Asia.[19]

Dracunculiasis

Dracunculiasis is also known as Guinea-worm disease. There were 126 cases of dracunculiasis in 2014, a decrease from 542 cases in 2012,[20] and a substantial decrease from 3,500,000 cases in 1986.[21] It is not fatal, but can cause months of inactivity.[20] It is caused by drinking water contaminated by water fleas infected with guinea-worm larvae.[20] It is usually treated by World Health Organization volunteers who clean and bandage wounds caused by worms and return daily to pull the worm out a few more inches.[20] Approximately one year after infection, a painful blister forms and one or more worm emerges. Worms can be up to one meter long.[20] Dracunculiasis is preventable by water filtration, immediate case identification to prevent spread of disease, health education, and treating ponds with larvicide. An eradication program has been able to reduce prevalence.[20] As of 2014, the four endemic countries are Chad, Ethiopia, Mali, and South Sudan.[20]

Echinococcosis

The rates of echinococcosis is higher in rural areas, and there are more than one million people infected currently.[22] Untreated alveolar echinococcosis is fatal.[23] It is caused by ingesting parasites in animal feces.[24] Surgery and drugs can both be used to treat echinococcosis.[23] There are two versions of the disease: cystic and alveolar. Both versions involve an asymptomatic incubation period of several years. In the cystic version, liver cysts cause abdominal pain, nausea and vomiting while cysts in the lungs cause chronic cough, chest pain, and shortness of breath. In alveolar echinococcosis, a primary cyst develops, usually in the liver, in addition to weight loss, abdominal pain, general feeling of ill health, and signs of liver failure.[23] It can be prevented by deworming dogs, sanitation, proper disposal of animal feces, health education, and livestock vaccination.[25] Cystic echinococcosis is found in the eastern portion of the Mediterranean region, northern Africa, southern and eastern Europe, the southern portion of South America, and central Asia. Alveolar echinococcosis is found in western and northern China, Russia, Europe, and northern North America.[24] It can be diagnosed through imaging techniques and serological tests.[25]

Endemic treponematoses (Yaws)

There are limited data available on the prevalence of yaws, although it primarily affects children.[26] The mortality risk is very low, but the disease causes disfigurement and disability if untreated.[26] It is a chronic bacterial infection, transmitted by skin contact, and caused by treponemes.[26] It is treated with antibiotics.[26] It can be prevented through improved hygiene and sanitation.[26] The most common symptom is skin lesions.[26] It is most prevalent in the warm, moist, tropical regions of the Americas, Africa, Asia, and the Pacific.[26]

Foodborne trematodiases

The foodborne trematode infections include clonorchiasis, opisthorchiasis, fascioliasis, and paragonimiasis. These infections are all zoonotic, primarily affecting domestic or wild animals, but also transmitted to humans. They are acquired by eating food, such as raw fish, contaminated with the larval stages of the parasites. At least 40 million people are thought to be infected.[27]

Human African trypanosomiasis

African trypanosomiasis is also known as African sleeping sickness. There are fewer than 10,000 cases currently.[28] The disease is always fatal if untreated. Human African trypanosomiasis is vector-borne,[17] and spread through the bite of the tsetse fly. The current forms of treatment are highly toxic and ineffective as resistance is spreading. The most common symptoms are fever, headache, lymphadenopathy, nocturnal sleeping pattern, personality changes, cognitive decline, and coma. It is diagnosed through an inexpensive serological test.

Leishmaniasis

The three forms of leishmaniasis are visceral (Kala-azar), cutaneous, and mucocutaneous.[29] There are an estimated 12 million people infected.[10] It is fatal if untreated and 20,000 deaths from visceral leishmaniasis occur annually.[30] It is a vector-borne disease[17] that is caused by the bite of sandflies. The only method of prevention is a vaccine that is under development and preventing sandfly bites. It can be treated with expensive medications.[31] At least 90 percent of visceral leishmaniasis occurs in Bangladesh, Brazil, Ethiopia, India, South Sudan, and Sudan. Cutaneous leishmaniasis occurs in Afghanistan, Algeria, Brazil, Colombia, Iran, Pakistan, Peru, Saudi Arabia, and Syria. Around 90 percent of mucocutaneous leishmaniasis occurs in Bolivia, Brazil, and Peru.[29] Diagnosis can by made by identifying clinical signs, serological tests, or parasitological tests.[32]

Leprosy

There were 189,018 known cases of leprosy in March 2013, and 232,857 new cases were diagnosed in 2012.[33] There are one to two million individuals currently disabled or disfigured due to past or present leprosy.[34] Leprosy causes disfigurement and physical disabilities if untreated. It is curable if treated early.[34] It is caused by bacteria and transmitted through droplets from the mouth and nose of infected individuals.[35] Treatment requires multidrug therapy.[33] The BCG vaccine has some preventative effect against leprosy. Leprosy has a 5–20 year incubation period, and the symptoms are damage to the skin, nerves, eyes, and limbs.[35] It is found in Angola, Brazil, Central African Republic, Democratic Republic of the Congo, India, Madagascar, Mozambique, Nepal, Tanzania.[33]

Lymphatic filariasis

Lymphatic filariasis is also known as elephantiasis. There are approximately 120 million individuals infected[36] and 40 million with deformities.[11] It is rarely fatal.[37] Lymphatic filariasis has lifelong implications, such as lymphoedema of the limbs, genital disease, and painful recurrent attacks. Most people are asymptomatic, but have lymphatic damage. Up to of 40 percent of infected individuals have kidney damage.[38] It is a vector-borne disease,[17] caused by nematode worms that are transmitted by mosquitoes.[38] It can be treated with cost-effective antihelminthic treatments,[39] and washing skin can slow or even reverse damage.[40] It is diagnosed with a finger-prick blood test.[37] Approximately two-thirds of cases are in Southwest Asia and one-third in Africa.[36]

Onchocerciasis

Onchocerciasis is also known as "river blindness". There are 37 million people infected[10] and prevalence is higher in rural areas.[41] It causes blindness, skin rashes, lesions, intense itching, and skin depigmentation.[42] It is a vector-borne[17] disease, caused by filarial worm infected blackflies.[42] It can be treated with ivermectin.[42] It can be prevented by insecticide spraying or preventative dosing with ivermectin.[41] The symptoms are generally itching and skin lesions.[41] Over 99 percent of cases are in Sub-saharan Africa.[41]

Rabies

There are two forms of rabies: furious and paralytic. There are 60,000 deaths from rabies annually.[43] There is a higher prevalence in rural areas and it disproportionately affects children.[44] Rabies is usually fatal after symptoms develop.[45] It is caused by a lyssavirus transmitted through wounds or bites from infected animals.[44] It can be prevented in dogs by vaccination,[44] and cleaning and disinfecting bite wounds (post-exposure prophylaxis).[45] The first symptoms are fever and pain near the infection site which occur after a one to three month incubation period. Furious (more common type) rabies causes hyperactivity, hydrophobia, aerophobia, and death by cardio-respiratory arrest occurs within days. Paralytic rabies causes a slow progression from paralysis to coma to death.[44] Rabies is undiagnosable before symptoms develop. It can be detected through tissue testing after symptoms develop.[44] It is found in Asia and Africa.[43]

Schistosomiasis

11-year-old boy with ascites and portal hypertension due to schistosomiasis (Agusan del Sur, Philippines)
Main article: Schistosomiasis

There are over 200 million cases of schistosomiasis.[11] The disease can be fatal by causing bladder cancer and haematemesis.[11] It causes bladder fibrosis, liver fibrosis, portal hypertension, and cervical lesions (which increase HIV susceptibility for women).[11] Schistosoma species have a complex life cycle that alternates between humans and freshwater snails. Infection occurs upon contact with contaminated water. This disease is unique in that damage is not caused by the worms themselves, but rather by the large volume of eggs that the worms produce.[46] The symptoms are usually haematuria, bladder obstruction, renal failure, bladder cancer, periportal fibrosis, portal hypertension, ascites, varices.[10] Inexpensive praziquantel can be used to treat individuals with schistosomiasis, but cannot prevent reinfection. The cost of prevention is US$0.32 per child per year.[11] Mass deworming treatment with praziquantel, better access to safe water, sanitation, health education can all be used to prevent schistosomiasis.[10] Vaccines are under development. It can be diagnosed through a serological test, but it often produces false negatives.[11] Approximately 85 percent of cases are in sub-Saharan Africa.[11]

Soil-transmitted helminthiasis

Adult ascaris worms being removed from the bile duct of a patient in South Africa

The three major worm species responsible for soil-transmitted helminthiasis are Ascaris (roundworms), Trichuris (whipworm), the hookworms Necator americanus and Ancylostoma duodenale, and Strongyloides stercoralis.[47] There are 1.5 billion currently infected.[47] The mortality risk is very low.[10] The severity of symptoms depends on the number of worms in the body, but can include intestinal problems, lack of energy, and compromised physical and cognitive development.[47] Parasitic worms are generally transmitted via exposure to infected human feces and soil which are spread in the environment, for example, due to open defecation.[47] The most common symptoms are anemia, stunted growth, decreased physical fitness, decreased school performance and attendance.[10] The most common treatment is medicine.[47] It can be prevented through hygienically prepared food and clean water, improved sanitation, periodic deworming, and health education.[47] The World Health Organisation recommends mass deworming without prior diagnosis.[47] Soil-transmitted heminthiasis occurs in sub-Saharan Africa, the Americas, China, and east Asia.[47]

Taeniasis/cysticercosis

Cysticercosis is a tapeworm larvae infection, whilst taeniasis is an adult tapeworm infection.[48] Both belong to the group of helminthiasis. Cysticercosis is the most common preventable cause of epilepsy in the developing world.[49] Taeniasis is not fatal, although cysticercosis can cause epilepsy and neurocystocercosis can be fatal.[49][50] Taeniasis is usually contracted after eating undercooked contaminated pork. Cysticercosis occurs after ingestion of contaminated food, water, or soil.[48] Taeniasis has mild symptoms, including abdominal pain, nausea, diarrhea, or constipation. Cysticercosis involves cysts and lesions that can cause headaches, blindness, seizures, hydrocephalus, meningitis, and dementia.[50] Drugs are used to treat both diseases.[50] Infection can be prevented through stricter meat-inspection standards, livestock confinement, improved hygiene and sanitation, health education, safe meat preparation, and identifying and treating human and pig carriers.[51] It is found in Asia, Africa, Latin America, particularly on farms in which pigs are exposed to human excrement.[49]

Trachoma

There are 21.4 million people infected with trachoma, of whom 2.2 million are partially blind and 1.2 million are blind. The disease disproportionately affects women and children.[52] The mortality risk is very low, although multiple re-infections eventually lead to blindness.[10][52] It is caused by a micro-organism that spreads through eye discharges (on hands, cloth, etc.) and by "eye-seeking flies".[52] It is treated with antibiotics. The only known prevention method is interpersonal hygiene. The symptoms are internally scarred eyelids, followed by eyelids turning inward.[52] It is found in Africa, Asia, Central and South America, Middle East, and Australia.[52]

Economic impact

Conteh, Engels, and Molyneux attribute the low cost of treatment for NTDs to the large scale of the programs, free provision of drugs by pharmaceutical companies, delivery modes of drugs, and the un-paid volunteers who distribute the drugs. They also argue that the economic burden of NTDs is undervalued and therefore the corresponding economic impact and cost-effectiveness of decreased prevalence of NTDs is underestimated.[53] The investment return on measures to control neglected tropical diseases is estimated to be between 14–30 percent, depending on the disease and region.[54] The long term benefits of deworming include a decrease in school absenteeism by 25 percent, and an increase in adult earnings by 20 percent.[55]

The cost of treatment of some of these diseases, however, such as Buruli ulcer, can amount to over twice the yearly income of an average household in the lowest income quartile, while for the highest income quartile, the burden is slightly less than the average household income. These enormous financial costs often cause deferral of treatment and financial ruin, but there is inequality between the wealthy and poor in terms of economic burden. These diseases also cost the government in terms of health care and lost worker productivity through morbidity and shortened life spans.In Kenya, for example, deworming is estimated to increase average adult income by 40 percent, which is a benefit-to-cost ratio of 100. Each untreated case of Trachoma is estimated to cost US$118 in lost productivity. Each case of schistosomiasis causes a loss of 45.4 days of work per year. Most of the diseases cost the economies of various developing countries millions of dollars. Large scale prevention campaigns are predicted to increase agricultural output and education levels.[53]

Social impact

Several NTDs, such as leprosy, cause severe deformities that result in social stigma. Lymphatic filariasis, for example, causes severe deformities that can result in denial of marriage and inability to work.[11] Studies in Ghana and Sri Lanka have demonstrated that support groups for patients with lymphatic filariasis can increase participants' self-esteem, quality of life, and social relations through social support and providing practical advice on how to manage their illness.[56]

Deworming treatment is correlated with increased school attendance.[11]

The impact of NTDs is tied to gender in some situations. NTDs disproportionately affect females, especially schistosomiasis, dengue, hookworm infections during pregnancy, and the risk of transferring Chagas Disease during pregnancy.[57] A study in Uganda found that women were more easily able to obtain treatment because they had fewer occupational responsibilities than men and were more trusting of treatment, but ignorance of the effects of medicines on pregnant women prevented adequate care. The paper concludes that gender should be considered when designing treatment programs.[58]

Health impact

Fenwick claims that the millennium development goals, such as education, child mortality, and maternal health are impossible to fulfill with the current high prevalence of NTDs. He also states that many individuals are afflicted by more than one NTD.[11]

Deworming treatments in those who are infected are correlated with healthy weight gain since worms are often partially responsible for malnutrition.[11][59] Whether or not mass deworming campaigns improve long term outcomes is unclear.[59] This included a lack of definite proof of sustained health benefits with respect to nutritional status, haemoglobin in blood and levels of school attendance or performance.[59] To achieve health gains in the longer term, improvements in sanitation and hygiene bevaviours are also required, together with deworming treatments.

Hotez argues for inclusion of NTDs into initiatives for malaria, HIV/AIDS, and tuberculosis given the strong link between these diseases and NTDs. He also notes the correlation between high rates of NTDs and high rates of non-communicable chronic diseases such as heart disease and cancer. He attributes these to the debilitating effect of NTDs and their long term toll on health.[57]

Reasons for neglect

Feasey argues that this group of diseases has been overlooked because they mainly affect the poorest countries of the developing world and because of recent emphasis on decreasing the prevalence of HIV/AIDS, tuberculosis, and malaria.[10] Fenwick also argues that far more resources are given to the "big three" diseases, HIV/AIDS, malaria, and tuberculosis, because of their higher mortality and public awareness rates.[11] He states that the importance of neglected tropical diseases has been underestimated since many are asymptomatic and have long incubation periods. The connection between a death and a neglected tropical disease that has been latent for a long period of time is not often realized.[11] According to the Financial Times, reason for neglect for these disease is that they are not commercial and consequently patents and profit play no role in stimulating innovation. Like all non-commercial areas, these diseases are the responsibility of governments and philanthropy (including industry philanthropy).[60]

Prevention

Fenwick argues that prevention and eradication are important because "of the appalling stigma, disfigurement, blindness and disabilities caused by NTDs."[11] According to a paper published in 2013, there is potential for eliminating or eradicating dracunculiasis, Leprosy, Lymphatic filariasis, Onchocerciasis, Trachoma, Sleeping sickness, Visceral leishmaniasis, and Canine rabies within the next ten years.[57]

The spread of those neglected tropical diseases that are vector-borne can be reduced by vector control.

Policy initiatives

There are many prevention and eradication campaigns funded for example by the World Health Organization, US Agency for International Development, Bill and Melinda Gates Foundation, UK Department for International Development.[11]

WHO Roadmap of 2012

WHO published in 2012 the NTD "roadmap" which contains milestones for 2015 and 2020 and which specifies targets for eradication, elimination, and intensified control of the different NTDs.[61] For example:

Others

The U.S. Food and Drug Administration priority review voucher is an incentive for companies to invest in new drugs and vaccines for tropical diseases. A provision of the Food and Drug Administration Amendments Act (HR 3580) awards a transferable "priority review voucher" to any company that obtains approval for a treatment for one of the listed diseases. The voucher can later be used to accelerate review of an unrelated drug. This program is for all tropical diseases and includes medicines for malaria and tuberculosis. The first voucher given was for Coartem, a malaria treatment.[62] It does not use or define the term "neglected" though most of the diseases listed are often included on lists of neglected diseases.

The prize was proposed by Duke University faculty Henry Grabowski, Jeffrey Moe, and David Ridley in their 2006 Health Affairs paper: "Developing Drugs for Developing Countries."[63] In 2007 United States Senators Sam Brownback (R-KS) and Sherrod Brown (D-OH) sponsored an amendment to the Food and Drug Administration Amendments Act of 2007. President George W. Bush signed the bill in September 2007.

Integration with WASH programs

Water, sanitation, and hygiene (WASH) interventions are essential in preventing many NTDs, for example soil-transmitted helminthiasis.[64] Mass drug administrations alone will not protect people from re-infection. A more holistic and integrated approach to NTDs and WASH efforts will benefit both sectors along with the communities they are aiming to serve. This is especially true in areas that are endemic with more than one NTD.[64]

In August 2015 the World Health Organization unveiled a global strategy and action plan to integrate WASH with other public health interventions in order to accelerate elimination of NTDs.[65] The plan aims to intensify control or eliminate certain NTDs in specific regions by 2020 and refers to the NTD "roadmap" milestones from 2012 that include for example eradication of dracunculiasis by 2015 and of yaws by 2020, elimination of trachoma and lymphatic filariasis as public health problems by 2020, intensified control of dengue, schistosomiasis and soil-transmitted helminthiases.[66]

A closer collaboration between WASH and NTD programmes can lead to synergies. They can be achieved through collaborative planning, delivery and evaluation of programmes, strengthening and sharing of evidence, and using monitoring tools to improve the equity of health services.[67]

Reasons why WASH plays an important role in NTD prevention and patient care include:[66]

Pharmaceutical market and initiatives

Biotechnology companies in the developing world have targeted neglected tropical diseases due to need to improve global health.[79]

Mass drug administration is considered a possible method for eradication, especially for lymphatic filariasis, onchocerciasis, and trachoma, although drug resistance is a potential problem.[80] According to Fenwick, Pfizer donated 70 million doses of drugs in 2011 to eliminate trachoma through the International Trachoma Initiative.[11] Merck has helped The African Programme for the Control of Onchocerciasis (APOC) and Oncho Elimination Programme for the Americas to greatly diminished the impact of Onchocerciasis by donating ivermectin.[11] Merck KGaA pledged to give 200 million tablets of praziquantel over 10 years, the only cure for schistosomiasis.[81] GlaxoSmithKline has donated two billion tablets of medicine for lymphatic filariasis and pledged 400 million deworming tablets per year for five years in 2010. Johnson & Johnson has pledged 200 million deworming tablets per year.[11] Novartis has pledged leprosy treatment, EISAI pledged two billion tablets to help treat lymphatic filariasis.[11]

NGO initiatives

There are currently only two donor-funded non-governmental organizations that focus exclusively on NTDs:[82] the Schistosomiasis Control Initiative and Deworm the World. Despite under-funding, many neglected diseases are cost-effective to treat and prevent. The cost of treating a child for infection of soil transmitted helminths and schistosomes (some of the main causes of neglected diseases), is less than US$0.50 per year, when administered as part of school-based mass deworming by Deworm the World. This programme is recommended by Giving What We Can and the Copenhagen Consensus Centre as one of the most efficient and cost-effective solutions. The efforts of Schistosomiasis Control Initiative to combat neglected diseases include the use of rapid impact packages: supplying schools with packages including four or five drugs, and training teachers in how to administer them.

Public-private initiatives

In 2013, the Government of Japan, five Japanese pharmaceutical companies, the Bill and Melinda Gates Foundation, and the UNDP established a new public-private partnership, Global Health Innovative Technology Fund. They pledged over US$100 million to the fund over five years, to be awarded as grants to R&D partnerships across sectors in Japan and elsewhere, working to develop new drugs and vaccines for 17 neglected diseases, in addition to HIV, malaria and tuberculosis.[83][84][85] Affordability of the resulting drugs and vaccines is one of the key criteria for grant awards.[83]

WIPO Re:Search was established in 2011 by the World Intellectual Property Organization in collaboration with BIO Ventures for Global Health (BVGH) and with the active participation of leading pharmaceutical companies and other private and public sector research organizations. It allows organizations to share their intellectual property, compounds, expertise, facilities and know-how royalty-free with qualified researchers worldwide working on new solutions for NTDs, malaria and tuberculosis.[86][87]

Others

An open-access journal dedicated to neglected tropical diseases called PLOS Neglected Tropical Diseases first began publication in 2007. There is also an international group dedicated to decreasing the prevalence of neglected tropical diseases called the Global Network for Neglected Tropical Diseases.[10]

Epidemiology

The six most common NTDs include soil-transmitted helminths (STHs)—specifically roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura) and hookworms (Necator americanus and Ancylostoma duodenale)—schistosomiasis, trachoma, and lymphatic filariasis (LF).[64] These diseases affect one-sixth of the world’s population with 90 percent of the disease burden occurring in sub-Saharan Africa.[64]

See also

References

  1. ↑ Hotez PJ, Kamath A (2009). Cappello, Michael, ed. "Neglected Tropical Diseases in Sub-Saharan Africa: Review of Their Prevalence, Distribution, and Disease Burden". PLoS Negl Trop Dis 3 (8): e412. doi:10.1371/journal.pntd.0000412. PMC 2727001. PMID 19707588.
  2. ↑ "Making the Case to Fight Schistosomiasis". National Public Radio. Retrieved 2008-12-01.
  3. ↑ Hotez PJ (January 2010). "How To Cure 1 Billion People? — Defeat Neglected Tropical diseases". Scientific America 302 (1): 90–4, 96. doi:10.1038/scientificamerican0110-90. PMID 20063641.
  4. ↑ Mike Shanahan (31 January 2006). "Beat neglected diseases to fight HIV, TB and malaria". SciDev.Net.
  5. ↑ Reddy M, Gill SS, Kalkar SR, Wu W, Anderson PJ, Rochon PA (October 2007). "Oral drug therapy for multiple neglected tropical diseases: a systematic review". JAMA 298 (16): 1911–24. doi:10.1001/jama.298.16.1911. PMID 17954542.
  6. ↑ http://www.dndi.org/
  7. 1 2 http://www.who.int/neglected_diseases/about/en/
  8. ↑ GBD 2013 Mortality and Causes of Death, Collaborators (17 December 2014). "Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013.". Lancet 385 (9963): 117–71. doi:10.1016/S0140-6736(14)61682-2. PMC 4340604. PMID 25530442.
  9. ↑ "Guinea Worm Disease: Worldwide Case Totals". The Carter Center. Retrieved 15 January 2016.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Feasey N, Wansbrough-Jones M, Mabey DC, Solomon AW (2010). "Neglected tropical diseases". Br. Med. Bull. 93 (1): 179–200. doi:10.1093/bmb/ldp046. PMID 20007668.
  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Fenwick A (March 2012). "The global burden of neglected tropical diseases". Public Health 126 (3): 233–6. doi:10.1016/j.puhe.2011.11.015. PMID 22325616.
  12. ↑ "Neglected tropical diseases". World Health Organization. Retrieved 24 November 2015.
  13. 1 2 "Buruli Ulcer". World Health Organization. Retrieved 2016-05-02.
  14. 1 2 3 "Buruli Ulcer". Retrieved 12 March 2014.
  15. ↑ "Buruli Ulcer Endemic Countries". Retrieved 12 March 2014.
  16. 1 2 3 4 5 6 7 "Chagas disease (American trypanosomiasis)". Retrieved 12 March 2014.
  17. 1 2 3 4 5 "World Health Day 2014: small bite, big threat". Retrieved 12 March 2014.
  18. 1 2 3 4 5 6 "Dengue Control". Retrieved 12 March 2014.
  19. ↑ Chikungunya, WHO, retrieved 21 January 2016
  20. 1 2 3 4 5 6 7 "Dracunculiasis". Retrieved 13 March 2014.
  21. ↑ "Dracunculiasis eradication — global surveillance summary, 2009" (PDF). Wkly. Epidemiol. Rec. (World Health Organization) 85 (19): 166–76. May 2010. PMID 20449943.
  22. ↑ "Echinococcosis". Retrieved 16 March 2014.
  23. 1 2 3 "Signs, symptoms and treatment of echinococcosis". Retrieved 16 March 2014.
  24. 1 2 "Transmission of echinococcosis". Retrieved 16 March 2014.
  25. 1 2 "Surveillance, prevention and control of echinococcosis". Retrieved 16 March 2014.
  26. 1 2 3 4 5 6 7 "Yaws". Retrieved 16 March 2014.
  27. ↑ "Foodborne trematode infections". World Health Organization. Retrieved 24 November 2015.
  28. ↑ "Human African Trypanosomiasis: number of new cases falls to historical low in 50 years".
  29. 1 2 "Burden and Distribution". Retrieved 16 March 2014.
  30. ↑ "Leishmaniasis". Retrieved 16 March 2014.
  31. ↑ "Access to essential antileishmanial medicines and treatment". Retrieved 16 March 2014.
  32. ↑ "Diagnosis, detection and surveillance". Retrieved 16 March 2014.
  33. 1 2 3 "Leprosy Today". Retrieved 16 March 2014.
  34. 1 2 "Leprosy: the disease". Retrieved 16 March 2014.
  35. 1 2 "Leprosy".
  36. 1 2 "Epidemiology". Retrieved 16 March 2014.
  37. 1 2 "Forms of Lymphatic Filariasis and diagnosis". Retrieved 16 March 2014.
  38. 1 2 "Lymphatic filariasis". Retrieved 16 March 2014.
  39. ↑ Mohammed KA, Hail HJ, Gabrielli AF, et al. (2008). Utzinger J, ed. "Triple Co-Administration of Ivermectin, Albendazole and Praziquantel in Zanzibar: A Safety Study". PLoS Negl Trop Dis 2 (1): e171. doi:10.1371/journal.pntd.0000171. PMC 2217668. PMID 18235853.
  40. ↑ "Clinical manifestations". Retrieved 16 March 2014.
  41. 1 2 3 4 "Onchocerciasis". Retrieved 16 March 2014.
  42. 1 2 3 "Onchocerciasis". Retrieved 16 March 2014.
  43. 1 2 "Rabies". Retrieved 16 March 2014.
  44. 1 2 3 4 5 "About rabies". Retrieved 16 March 2014.
  45. 1 2 "Rabies". Retrieved 16 March 2014.
  46. ↑ "Schistosomiasis Fact Sheet". CDC, Division of Parasitic Diseases. Retrieved 2008-12-03.
  47. 1 2 3 4 5 6 7 8 "Soil-transmitted helminth infections". Retrieved 16 March 2014.
  48. 1 2 "Transmission of taeniasis/cysticercosis". Retrieved 13 March 2014.
  49. 1 2 3 "About Taeniasis/cysticercosis". Retrieved 13 March 2014.
  50. 1 2 3 "Signs, symptoms and treatment of taeniasis/cysticercosis". Retrieved 13 March 2014.
  51. ↑ "Surveillance, prevention and control of taeniasis/cysticercosis". Retrieved 13 March 2014.
  52. 1 2 3 4 5 "Priority eye diseases". Retrieved 16 March 2014.
  53. 1 2 Conteh L, Engels T, Molyneux DH (January 2010). "Socioeconomic aspects of neglected tropical diseases". Lancet 375 (9710): 239–47. doi:10.1016/S0140-6736(09)61422-7. PMID 20109925.
  54. ↑ Molyneux DH (2004). ""Neglected" diseases but unrecognised successes—challenges and opportunities for infectious disease control". Lancet 364 (9431): 380–3. doi:10.1016/S0140-6736(04)16728-7. PMID 15276399.
  55. ↑ "Deworm the World: the evidence for school-based deworming".
  56. ↑ Weiss MG (2008). "Stigma and the social burden of neglected tropical diseases". PLoS Negl Trop Dis 2 (5): e237. doi:10.1371/journal.pntd.0000237. PMC 2359851. PMID 18478049.
  57. 1 2 3 Hotez PJ (November 2013). "NTDs V.2.0: "blue marble health"—neglected tropical disease control and elimination in a shifting health policy landscape". PLoS Negl Trop Dis 7 (11): e2570. doi:10.1371/journal.pntd.0002570. PMC 3836998. PMID 24278496.
  58. ↑ Rilkoff H, Tukahebwa EM, Fleming FM, Leslie J, Cole DC (2013). "Exploring gender dimensions of treatment programmes for neglected tropical diseases in Uganda". PLoS Negl Trop Dis 7 (7): e2312. doi:10.1371/journal.pntd.0002312. PMC 3708858. PMID 23875047.
  59. 1 2 3 Taylor-Robinson, DC; Maayan, N; Soares-Weiser, K; Donegan, S; Garner, P (14 November 2012). "Deworming drugs for soil-transmitted intestinal worms in children: effects on nutritional indicators, haemoglobin and school performance.". The Cochrane database of systematic reviews 11: CD000371. doi:10.1002/14651858.CD000371.pub5. PMID 23152203.
  60. ↑ http://www.ft.com/intl/cms/s/0/07bfe8f2-5e05-11e4-bc04-00144feabdc0.html#axzz3MMnaQdHZ
  61. ↑ World Health Organization (WHO) (2012). Accelerating work to overcome the global impact of Neglected Tropical Diseases. A roadmap for implementation. Geneva, Switzerland.
  62. ↑ "FDA Approves Coartem Tablets to Treat Malaria". USFDA. Retrieved 11 December 2009.
  63. ↑ Ridley DB, Grabowski HG, Moe JL (2006). "Developing drugs for developing countries". Health Aff (Millwood) 25 (2): 313–24. doi:10.1377/hlthaff.25.2.313. PMID 16522573.
  64. 1 2 3 4 Johnston, E. A.; Teague, Jordan; Graham, Jay P. (2015-06-11). "Challenges and opportunities associated with neglected tropical disease and water, sanitation and hygiene intersectoral integration programs". BMC Public Health 15 (1): 547. doi:10.1186/s12889-015-1838-7. ISSN 1471-2458. PMID 26062691.
  65. ↑ "WHO strengthens focus on water, sanitation, and hygiene to accelerate elimination of neglected tropical diseases". World Health Organization (WHO). 27 August 2015. Retrieved 14 September 2015.
  66. 1 2 World Health Organization (WHO) (2015): Water Sanitation and Hygiene for accelerating and sustaining progress on Neglected Tropical Diseases. A global strategy 2015 - 2020. Geneva, Switzerland, p. 26
  67. ↑ "Collaboration between WASH and NTD". World Health Organization (WHO). Retrieved 14 September 2015.
  68. ↑ "NTDs and access to water and sanitation are major global challenges". World Health Organization (WHO). Retrieved 14 September 2015.
  69. ↑ "Facial cleanliness and environmental improvement are key to eliminating trachoma". World Health Organization (WHO). Retrieved 14 September 2015.
  70. ↑ "Sanitation prevents soil transmitted helminth infections". World Health Organization (WHO). Retrieved 14 September 2015.
  71. ↑ "Breeding sites for mosquitoes are reduced through improved sanitation and water management". World Health Organization (WHO). Retrieved 14 September 2015.
  72. ↑ "Protecting freshwater from contamination reduces schistosomiasis". World Health Organization (WHO). Retrieved 14 September 2015.
  73. ↑ "Safe water is essential to treat and care for NTDs". World Health Organization (WHO). Retrieved 14 September 2015.
  74. ↑ "WASH improves the quality of life for people affected by NTDs". World Health Organization (WHO). Retrieved 14 September 2015.
  75. ↑ Grimes, Jack E.T.; Croll, David; Harrison, Wendy E.; Utzinger, Jürg; Freeman, Matthew C.; Templeton, Michael R. (4 December 2014). "The Relationship between Water, Sanitation and Schistosomiasis: A Systematic Review and Meta-analysis". PLOS Neglected Tropical Diseases 8: e3296. doi:10.1371/journal.pntd.0003296. Retrieved 16 September 2015.
  76. ↑ Stocks, Meredith E. (25 February 2014). "Effect of Water, Sanitation, and Hygiene on the Prevention of Trachoma: A Systematic Review and Meta-Analysis". PLOS Medicine 11: e1001605. doi:10.1371/journal.pmed.1001605. Retrieved 16 September 2015.
  77. ↑ Strunz, Eric C. (24 March 2014). "Water, Sanitation, Hygiene, and Soil-Transmitted Helminth Infection: A Systematic Review and Meta-Analysis". PLOS Medicine 11: e1001620. doi:10.1371/journal.pmed.1001620. Retrieved 16 September 2015.
  78. ↑ Campbell, Suzy J. (10 April 2014). "Water, Sanitation, and Hygiene (WASH): A Critical Component for Sustainable Soil-Transmitted Helminth and Schistosomiasis Control". PLOS Neglected Tropical Diseases 8: e2651. doi:10.1371/journal.pntd.0002651. Retrieved 16 September 2015.
  79. ↑ Frew SE, Liu VY, Singer PA (2009). "A business plan to help the 'global South' in its fight against neglected diseases" (PDF). Health Aff (Millwood) 28 (6): 1760–73. doi:10.1377/hlthaff.28.6.1760. PMID 19887417.
  80. ↑ Keenan JD, Hotez PJ, Amza A, et al. (2013). "Elimination and eradication of neglected tropical diseases with mass drug administrations: a survey of experts". PLoS Negl Trop Dis 7 (12): e2562. doi:10.1371/journal.pntd.0002562. PMC 3855072. PMID 24340111.
  81. ↑ Burns, Melinda (3 October 2010). "Lifesaving Drug Praziquantel Too Expensive for Africa". Pacific Standard. The Miller-McCune Center for Research, Media and Public Policy. Retrieved 8 December 2015.
  82. 1 2 "Japan in pioneering partnership to fund global health research", by Andrew Jack, Financial Times, May 30, 2013
  83. ↑ "An Audience with … Tachi Yamada", by Asher Mullard, Nature magazine, September 2013, Volume 12, p.658
  84. ↑ "Joining the Fight Against Neglected Diseases", Science magazine, June 7, 2013, Volume 340, p.1148
  85. ↑ Ramamoorthi, R; Graef, KM; Dent, J (December 2014). "WIPO Re:Search: Accelerating anthelmintic development through cross-sector partnerships.". International journal for parasitology. Drugs and drug resistance 4 (3): 220–5. doi:10.1016/j.ijpddr.2014.09.002. PMID 25516832.
  86. ↑ "WIPO Re:Search". Retrieved 16 March 2015.

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