Neglected Tropical Diseases (NTDs) PDF

Neglected Tropical Neglected Neglected tropical diseases Tropic Diseases Diseases Neglected = historically not really dealt with by drugs companies due to economic considerations Tropical = occurring in developi...

Neglected Tropical Neglected Neglected tropical diseases Tropic Diseases Diseases Neglected = historically not really dealt with by drugs companies due to economic considerations Tropical = occurring in developing regions of Africa, Asia, and South and central America Diseases = I am sure you can work this out… Samuel Dean, Assistant Professor [email protected] First coined in xxx by the WHO to cover 17 different infectious diseases The term was ivented to increase lobbying power and raise the profile of the diseases Originally caused by infectious agents (bacteria, viruses, parasites) By the end of this session you will be able to: Give several examples of Neglected Tropical Diseases (NTDs) Understand how the health impact of NTDs can be measured Know that many, but not all, NTDs are spread by vectors Understand some of the interventions used to control NTDs Describe two examples of NTDs caused by parasitic worms What are Neglected Tropical Diseases (NTDs)? Neglected = historically not really dealt with by drugs companies due to economic considerations Tropical = occurring in developing regions of Africa, Asia, and South and central America Diseases = I am sure you can work this out… In 2007 WHO and partners brought together various disease initiatives under the umbrella of the NTD “brand” The term was coined to increase lobbying power and raise the profile of the diseases Their inclusion was on the basis that they are good candidates for control and elimination: Their transmission characteristics Treatment opportunities  WHO have designated 20 Neglected tropical diseases Bacteria Protozoa (single celled eukaryotic) 1. Buruli ulcer (Mycobacterium ulcerans) 1. Chagas disease (Trypanosome cruzi) 2. Leprosy (Mycobacterium leprae) 2. Human African trypanosomiasis 3. Trachoma (Chlamydia trachomatis) (Trypanosoma brucei) 4. Yaws (Treponema pallidum) 3. Leishmaniasis (Leishmania spp) Viruses Parasitic worms 1. Dengue and chikungunya (virus) 1. Dracunculiasis (guinea worm) 2. Rabies (rabies virus) 2. Echinococcosis (tapeworm) 3. Foodborne trematodiases (platyhelminth worm) Others 4. Elephantitis/ Lymphatic filariasis (nematode worms) 1. Mycetoma, chromoblastomycosis and other 5. River blindness / Onchocerciasis (Onchocerca volvulus) deep mycoses (fungus) 6. Schistosomiasis (schistosoma worm) 2. Scabies and other ectoparasitoses (mites) 7. Soil-transmitted helminthiases (nematode worm) 3. Snakebite envenoming (snake bites) 8. Taeniasis and cysticercosis (tapeworm) All but 1 are infectious diseases  NTD spread Most NTDs are spread by a vector (or intermediate host) Mosquitos (Dengue, chikungunya, Lymphatic filariasis) Flies (African Sleeping Sickness, Leishmaniasis, river blindness, Tsetse fly mosquito Trachoma) Water fleas (Dracunculiasis) Mites (Scabies) Snails (Schistosomiasis) Biting dogs (Rabies) Sand fly Scabies mite Contaminated food (Foodborne trematodiases, Taeniasis and cysticercosis) Other mechanisms of spread: Black fly Snail Contaminated soil (Echinococcosis, Soil-transmitted helminthiases) Person-person (Leprosy, Trachoma, Yaws) Transmission mechanism unknown: Bazaar fly Burelli ulcur Mycetoma, chromoblastomycosis and other deep mycoses Scary rabid dog (mycetoma)  Number of people requiring interventions for NTDs (2015) It is likely that all of the world’s population living below the World Bank poverty line of US$1.90 per day are infected with one or more of these NTDs, corresponding to, at least, 10% of the global population  NTD mortality and morbidity Health Impact measured in the following ways: Mortality (= # of deaths) Morbidity – Disability Adjusted Life Years (DALYs) = Years of Life Lost (YLLs) due to premature mortality + Years Lived with Disability (YLDs) At risk – number of people living in endemic areas who are at risk of being infected and contracting disease Impact of some NTDs is not well captured by only assessing deaths Annual NTD deaths, DALYs and prevalence DALYs Deaths NTDs in 2016: ~1 billion people infected with a NTD Another 1-2 billion people at risk >186,000 people died from NTDs >18.6 million DALYs from NTDs For context in 2016: Ischaemic heart disease killed 9.4 million people (the biggest killer), >200 billion DALYs Road deaths killed 1.4 million people (82 billion DALYs) HIV/AIDS killed 1 million people (~60 billion DALYs) Malaria killed 446,000 people (37 billion DALYs) Economic reasons for spending on NTD prevention Spending on NTD interventions are one of the “best buys” in global public health: Improve the health and well-being of populations Benefits the most disadvantaged citizens financially Increase productivity for society Every $1 invested in preventive chemotherapy for NTDs gives rise to a net benefit of up to $25: Reduced medical expenses paid for by the patient (termed “out of pocket” expenditure) Reduced lost productivity Represents a 30% annualised rate of return over 12 years Every $1 invested in improving water and sanitation gives rise to a return of >$5: Reduced health care costs for individuals and society Greater productivity Evidence in favour of including certain NTD interventions is based on a cost per disability-adjusted life year (DALY) averted of $250 or less. The cost of delivering preventive chemotherapy, estimated to be $0.4 per person, is low and could be even lower with cross-cutting approaches  NTD Funding Funding for NTDs has been essentially flat for the past decade at ~$300 million For every $1 spent on NTD programmes, $26 in donated medicines are given through partnerships with pharmaceutical companies: Pharmaceutical companies donate an average of nearly three billion tablets of medicines annually, worth hundreds of millions of dollars, More companies are committing funds to areas such as vector control and diagnostics However: WHO estimated that NTD interventions could cost up to $750 million a year by 2020 over and above the costs of vector control and donations of medicines è this is a big gap! NTDs must be accounted for in national strategies and budgets for health, development and poverty alleviation and not only in NTD strategic plans. This IS affordable - it would require less than 1% of domestic expenditure on health to meet the 2030 targets SOURCE: KFF analysis of data from the Office of Management and Budget, First WHO roadmap WHO 2012 – 2020 NTD roadmap is a series of goals and strategies to combat NTDs  2012 – 2020 Progress on NTD interventions Dengue: Vector control interventions established in 10 endemic priority countries Control and surveillance systems established in five of the six WHO regions Schistosomiasis: 67% preventive chemotherapy coverage rate achieved for school-aged children Soil -transmitted helminthiases: 59% of preschool and school-aged children who require treatment are regularly treated Trachoma: More than 1 million surgical treatments provided New treatment approaches: Ivermectin–diethylcarbamazine citrate–albendazole (IDA) for lymphatic filariasis fexinidazole for human African trypanosomiasis paediatric praziquantel (in the pipeline) for schistosomiasis antibiotics for Buruli ulcer (instead of surgical treatment) azithromycin for yaws (instead of injected benzathine benzylpenicillin) New diagnostics: Rapid and multiplex diagnostic tests for onchocerciasis, lymphatic filariasis, yaws and human African trypanosomiasis; circulating cathodic antigen assay for Schistosoma mansoni; others in the pipeline, e.g. mycolactone rapid diagnostic test for Buruli ulcer Novel vector control tools: Including sterile insect technique (e.g. incompatible insect technique and cytoplasmic incompatibility) and population replacement techniques (by Wolbachia spp.), new traps and insecticides  Impact of 2012 Roadmap against NTDs 600 million fewer people require interventions against NTDs than in 2010 42 countries, territories and areas had eliminated at least one NTD by 2020 66% preventive coverage (2019) for populations at risk in endemic areas, up from 42% in 2012  Key Definitions 1. Eradication: Permanent reduction to zero of the worldwide incidence of infection caused by a specific pathogen No risk of reintroduction Smallpox is the only human disease ever to be eradicated 2. Elimination (interruption of transmission): Reduction to zero of the incidence of infection caused by a specific pathogen in a defined geographical area, with minimal risk of reintroduction Continued action to prevent re-establishment of transmission may be required. 3. Elimination as a public health problem Reduction of infection and disease to measurable targets set by WHO Continued action is required to maintain the targets and/or to advance interruption of transmission 4. Control: Reduction of disease incidence, prevalence, morbidity and/or mortality to a locally acceptable level Continued interventions are required to maintain the reduction  Impacts on specific NTDs Dracunculiasis: On the verge of eradication Only 54 human cases were reported in four countries in 2019 Human African trypanosomiasis: Eliminated as a public health problem New reported cases has fallen to 7000 in 2012) Leprosy: New reported cases declined by 1% per year since 2010 21.4% reduction in number of cases with grade 2 disabilities, most endemic countries achieved elimination as a public health problem (identified as less than one case on treatment per 10 000 population) lymphatic filariasis: 43% (or 648 million) reduction in the population requiring preventative chemotherapy eliminated as public health problems in 17 countries Yaws: Eliminated in India Onchocerciasis: Eliminated in four countries in the Region of the Americas; Rabies: Elimination of dog-mediated human rabies in Mexico Trachoma Eliminated as public health problems in 10 countries Leishmaniasis: Annual in South-East Asia cases reduced to < 5,000 (from >50,000 cases)  2020 Targets missed Disease 2020 Target missed Leishmaniasis (cutaneous) 70% of cases detected in Eastern Mediterranean Lymphatic filariasis Global elimination as a public health problem Rabies Elimination in Latin America, SE Asia, Western Pacific Schistosomiasis Elimination in multiple countries Soil-transmitted helminthiases Treating 75% of preschool and school-aged children that need to be treated Trachoma Elimination as a public health problem in all endemic countries Yaws Global eradication Leprosy Changing laws that allow discrimination on the basis of leprosy Despite substantial progress in reducing the overall burden, many of the targets set for 2020 were not achieved WHO roadmap 2021 – 2030: targets “by 2030, we aim to free more than 1 billion people who currently require interventions against neglected tropical diseases, and save millions more from catastrophic out-of-pocket expenditure.” Over-arching Targets for 2030 1. 90% reduction in people requiring interventions against NTDs 2. 75% reduction in disability-adjusted life years related to NTDs 3. 100 countries having eliminated at least one neglected NTDs 4. 2 NTDs eradicated Disease–specific targets 1. 2 NTDs Targeted for eradication: Dracunculiasis, Yaws 2. 3 NTDs Targeted for elimination: Human African trypanosomiasis, Leprosy, Onchocerciasis 3. 8 NTDs Targeted for elimination as a public health problem: Chagas disease, Human African trypanosomiasis (rhodesiense), Leishmaniasis (visceral), Lymphatic filariasis, Rabies, Schistosomiasis, Soil-transmitted helminthiases, Trachoma 4. Targeted for control: Buruli ulcer, Dengue and chikungunya, Echinococcosis, Foodborne trematodiases, Leishmaniasis (cutaneous), Mycetoma, chromo- blastomycosis and other deep mycoses, Scabies and other ectoparasitoses, Snakebite envenoming, Taeniasis and cysticercosis WHO roadmap 2020 - 2030: HOW? Strategies to achieve this 1. Integrate NTDs into national healthcare systems of affected countries 2. Where possible do an integrated NTD approach 57% of the 1.7 billion people requiring preventative chemotherapy for at least one NTD require treatment for one or two diseases 43% for three or more diseases Core strategic interventions 1. Preventive chemotherapy 2. WASH (water, sanitation and hygiene) 3. Vector control 4. Veterinary public health 5. Case management Water, Sanitation, and Hygiene (WASH) 785 million people do not have access to basic drinking-water services 663 million people do not have access to adequate water sources 2.4 billion people lack access to adequate sanitation 946 million people practice open defecation 2 billion people still do not have access to basic sanitation facilities such as private toilets or improved latrines Half the people in the developing world are suffering from one or more diseases associated with inadequate WASH Diarrheal illnesses: Causes more than 1.5 million deaths worldwide every year Mostly among children younger than five years of age. Soil-transmitted helminthiases (STHs): More than 1 billion people are infected with STHs Associated with >12,000 deaths each year, learning impairment, massive diarrhoea, and anaemia Improved WASH can result in a 29% reduction in illness Dracunculiasis / Guinea worm disease (GWD): Solely spread by contaminated water Causes prolonged disability Causes millions of dollars in economic losses each year, and decreases school attendance Improved water supplies can result in a 78% reduction in GWD Trachoma: The leading cause of preventable blindness with approximately 8 million people worldwide blind 84 million people in need of treatment. The spread of Trachoma is strongly related to overcrowding, the lack of water for washing the face and hands, and inadequate disposal of human and animal waste. Improving WASH can reduce trachoma by 27%. Schistosomiasis: ~200 million people are infected with schistosomiasis, Causes tens of thousands of deaths each year, mostly in sub Saharan Africa. Results from unsanitary disposal of human waste and the absence of nearby safe sources of water Basic sanitation can reduce Schistosomiasis by 77% Dengue, other arboviral diseases and lymphatic filariasis: Transmitted by mosquito species that thrive in urban areas where inadequate water supplies and sanitation, and poor wastewater and solid waste management provide favourable breeding conditions  How does WASH fit into the NTD roadmap? WASH-related aspects highlighted in green  Role of diagnostics THE NEED: Identification and treatment of cases so that they are not potential sources of infection Reduce morbidity by ensuring early detection and management Monitor disease trends and effectiveness of control programmes Especially for diseases that are nearing elimination, high-sensitivity and high-specificity diagnostics are required to reduce false positives/negatives HOWEVER: Investment in new diagnostics has been limited: ~ 5% of research and development investment for NTDs (compare with 39% devoted to medicines and vaccines, about 44% to basic research and about 12% to other areas) The market for many NTDs is small with a relatively short time to recoup investments Public-private initiatives are key to addressing the diagnostics need Types of diagnostics Many of the diagnostics are “19th century technology not suitable for 21st Century programs” (e.g. microscopic observation of faeces) There is a need to develop fast, accurate and cheap molecular diagnostics that require little training. Molecular tests all rely on a biomarker: Antigen Lateral flow Antibody ELISA Lateral flow rapid test (IgM/IgG) Nucleic acid PCR LAMP How does a lateral flow antigen test work? 1. Identify a biomarker (usually, but not always, a pathogen antigen) 2. Add biological sample to the sample pad 3. The sample flows through the conjugate pad that contains labelled antibodies specific to the antigen 4. Antibodies specific to the antigen are also adhered to the test line 5. If the antigen is present it is captured by the test line along with the labelled antibodies, visible as a line Sam’s 2021 COVID Christmas LFTs  Diagnostics – sensitivity and specificity Sensitivity = True Positive Rate Proportion of people who ARE positive that TEST positive Specificity = True Negative Rate Proportion people who ARE negative that TEST negative Scenario: A diagnostic has a 100% sensitivity and a 99% specificity If someone tests positive, what is the probability they ARE positive? Answer… it depends If incidence of disease is 1%, then there is only a 50% chance a positive result is a TRUE positive To be useful the diagnostic must therefore have a HIGHER SPECIFICITY when disease incidence is LOW This becomes especially relevant during the last mile of disease elimination  NTD challenges Political instability: Gaps in governance of NTD interventions Diversion of NTD funding to other causes Difficulties for implementation: disruption of infrastructure restricted access to local populations risks for health care personnel Migration and population movement can result in the introduction or reintroduction of diseases, particularly when displaced populations live in temporary accommodation with inadequate sanitation, poor water storage practices and limited access to health care. Climate change: Alters the epidemiology of vector-borne diseases and the spread of NTDs such as dengue and chikungunya. Antimicrobial and insecticide resistance: Expansion of preventive chemotherapy Widespread use of insecticides for vector control Zoonoses: Provides an animal reservoir E.g. Dracunculus medinensis infection in mammals other than human beings shows how challenges to eradication can manifest in the last stages – the last mile – of eradication Schistosomiasis (Bilharzia) The Carter Center, YouTube  Schistosomiasis – transmission and cause Schistosomiasis is caused by 6 different species of parasitic helminth worms (aka blood flukes) with a highly complex lifecycle Mammals including humans (Definitive host) Human hosts are infected through contact with contaminated water Most species live in the mesenteric vein system near the guts Female worms lay 200-3,000 per day in the blood (depends on species) The eggs somehow makes its way to the gut lumen (how is not known) Humans excrete the eggs in faeces or urine, depending on species Lifecycle in humans is ~6 – 7 weeks Snails (Intermediate host) When contaminated faeces or urine reaches fresh water the eggs hatch miracidium (hatchlings) Miracidium have just a few hours to swim to a snail of the right species The parasite migrates through the snail and ultimately sheds cercaria (larvae) Cercaria then swim using positive phototropism and chemoattractants to find a new host and reinfect by penetrating the (even unbroken) skin Boissier J, Mouahid G, Moné H. 2019. Schistosoma spp.Water and Sanitation for the 21st Century: Health and Microbiological Aspects of Excreta and Wastewater Management (Global Water Pathogen Project). Michigan State University. doi:10.14321/waterpathogens.45  Schistosoma worms form male-female pairs in the veins Schistosoma = “split body” female Name refers to the adult male worm’s lateral edges that fold to form a groove (“gynecophoral canal”) where the female worm resides Worms pair in the liver and migrate en copula to male either the mesenteric veins draining the intestines (S. mansoni and S. japonicum) or vesical venous plexus of the urogenital system (S. Schistosome worm pair (mammalian blood). Females haematobium) held in a groove of the male worm (10-20mm). Males Worms can live for several years in a host have suckers to hold on with.  Infective forms are highly motile Miracidium whizzing around using cilia to find Cercariae borrowing into human skin after a snail host being released from a snail  Schistosomiasis - epidemiology 51 endemic countries across Asia, Africa and parts of South America Range is defined by the presence of the specific snail species Affects 240 million people worldwide Approximately 779 million people are at risk of acquiring the infection 90% of affected people live in Africa In 2000, schistosomiasis caused: 55,000 deaths 4.3 million DALYs In 2016, schistosomiasis caused: 24,000 deaths 2.500 million DALYs The difference due to better availability of treatments Ranks second after malaria for parasitic diseases Mutapi F, Maizels R, Fenwick A, Woolhouse M. 2017. Human schistosomiasis in the post mass drug administration era. The Lancet Infectious Diseases 17:e42–e48. doi:10.1016/S1473-3099(16)30475-3  Schistosomiasis - pathology Initial rash at site of inoculation Acute phase characterised by Katayama syndrome: nocturnal fever, cough, myalgia (muscle aches and pains), headache, and abdominal tenderness lasts 14 – 84 days caused by migrating parasites and egg deposition Chronic phase: weakness, fatigue, abdominal pain Main damage done by the eggs stimulating the immune system Granuloma formation around schistosome eggs Fibrosis and lesions of organs containing trapped eggs (e.g. liver) Kidney dysfunction, blood in urine and burning while peeing Blood in stools and irregular bowel movement and diarrhea Male and female fertility defects In endemic areas children usually have their first infection by 2 yrs Associated with under-nutrition, lost years of schooling, growth stunting, cognitive impairment, exercise intolerance or general fatigue, chronic ill health and, in some cases, death Hepatosplenomegaly (liver and spleen swelling) in patient Children suffering from persistent and severe bilharzia infections are also likely to infected with Schistosomiasis masoni have chronic and irreversible diseases later in life, such as bladder cancer In women, infection can lead lead to female genital schistosomiasis (FGS) which can Danso-Appiah T. (2016) Schistosomiasis. In: Gyapong J., Boatin B. (eds) Neglected Tropical Diseases - Sub- cause complications in pregnancy and triple the risk of contracting HIV Saharan Africa. Neglected Tropical Diseases. Springer, Cham. https://0-doi- org.pugwash.lib.warwick.ac.uk/10.1007/978-3-319-25471-5_11  WHO have set out to eliminate schistosomiasis Drugs Preventative chemotherapy to break the chain of transmission Praziquantel (safe with cure rates as high as 100%) is the only WHO-recommended anthelminthic drug available for use in preventive chemotherapy WHO estimate that 218 million people required preventive treatment for schistosomiasis in 2015, but only about 66.5 million people (30.5%) received it Improved sanitation Hygiene education Access to potable (drinkable) water to prevent at-risk water contact Access to toilets and reducing open defecation Sewage treatment Pre-treatment of “night soil” (human faeces) before using as a fertiliser Toilets (Arrow) on stilts on the right of the Snail control Need for cheap and safe molluscicides house in Nokoué Lake (Southern Benin, West Africa) Vaccines Three vaccine candidates are undergoing clinical trial Currently there is no effective vaccine is available to prevent schistosomiasis Number of people treated with preventative chemotherapy world-wide 2006 - 2020 What happened here? (millions) (%) (%)  Dracunculiasis / Guinea worm disease (GWD) Guinea Worm Disease Eradication: Countdown to Zero (Carter Center) https://www.youtube.com/watch?v=oCB1A2gFvuU  Dracunculiasis History Known as a parasite of humans since about 1530 B.C. Dracunculus medinensis literally means the “little dragon from Medina.” Guinea worm is thought to be the "fiery serpent" referred to in the Bible. The symbol of a Physician is the "Caduceus". The serpents are believed to represent the Guinea worm being wrapped around a stick Persian physicians removing the D. medinensis parasite from patient during the 9th century Dracunculiasis - lifecycle People become infected when they drink water containing copepods (water fleas) that harbour infective larvae. The ingested copepods are killed by the digestive juices of the stomach. The released larvae then move to the small intestine, where they penetrate the intestinal wall and migrate to the connective tissues of the abdominal wall and the thorax. Male and female larvae mature and mate 60–90 days after infection. The male worm dies shortly after mating, and the female matures over the subsequent 10–14 months, slowly migrates to the surface of the body A blister then forms on the skin where the worm will eventually emerge, usually forms on the legs and feet. This blister causes a very painful burning feeling and it bursts within 24–72 hours. When blisters are submerged in water, the female worm releases larvae, which are ingested by copepods, thus completing the life cycle Dracunculiasis - epidemiology Affects poor communities in remote parts of Africa that do not have safe water to drink. Unsafe stagnant water includes ponds, pools in drying riverbeds, and shallow hand-dug wells without surrounding protective walls GWD is not normally caught from drinking flowing water (rivers and streams) Transmission has a seasonal pattern: In dry regions, people generally get infected during the rainy season, when stagnant surface water is available. In wet regions, people generally get infected during the dry season, when surface water is drying up and becoming stagnant Most common among young adults 15–45 years old Farmers, herders, and those fetching drinking water for the household may be more likely to become infected, possibly because they drink contaminated stagnant water while away from home The greatest risk for GWD is having GWD the year before People do not become immune to infection. The same water sources are repeatedly contaminated and conditions that support the spread of disease have not changed  Dracunculiasis – pathology Although it is only about one to two millimetres wide, the adult female worm is 60 to 100 centimetres long There are no symptoms for the first year, then, the person begins to feel ill: Slight fever Itchy rash Nausea Vomiting Diarrhoea Dizziness The wound often becomes infected causing: Worm under the skin Sepsis Tetanus Abscesses Cellulitis Rarely lethal The disability that occurs during worm removal and recovery prevents people from working in their fields, tending animals, going to school, and caring for their families Disability lasts 8.5 weeks on average but sometimes can be permanent Blister  Dracunculiasis – case management There are no vaccines or drugs to treat Dracunculiasis Once part of the worm begins to come out of the wound, the rest of the worm can only be pulled out a few centimetres each day by winding it around a piece of gauze or a small stick. The process usually takes weeks. Care must be taken not to break the worm during removal. If part of the worm is not removed, there is a risk for secondary bacterial infections and resulting complications. Anti-inflammatory medicine can help reduce pain and swelling. Antibiotic ointment can help prevent infections. It is critical to remove the worm before the infected patient can contaminate drinking water  Dracunculiasis – eradication program Eradication program began in 1980 Education Drink only water from protected sources (such as from boreholes or protected hand-dug wells) that are free from contamination. Cook fish and other aquatic animals (e.g., frogs, fish) well before Cloth filter distributed by the Guinea work eradication program eating them. Prevent people with blisters, swellings, wounds, and visible worms emerging from their skin from entering ponds and other water sources. WASH interventions Distribute basic water filters (e.g. Guinea worm cloth filter or a Guinea worm pipe filter) to remove the copepods Treat unsafe drinking water sources with chemicals to kill the copepods Provide targeted communities at risk for GWD with new safe sources of drinking water and repair broken safe water sources (e.g., hand- pumps) if possible. Water filter straw Dracunculiasis – the last mile Only 28 human cases reported worldwide in 2018: Angola (1 case) Chad (17 cases) South Sudan (10 cases) WHO 2021 NTD Roadmap Dracunculiasis – the last hurdle? HOWEVER - Dracunculiasis is a zoonotic disease! Aquatic animals (fish, frogs etc) can eat infected water fleas and pass on the disease upon consumption Chad reported 1,040 infected dogs and 25 cats Ethiopia reported 11 infected dogs, 5 cats, and 1 baboon Mali reported 18 infected dogs and 2 cats This provides the potential for re-introduction of Dracunculiasis to human populations Interventions now encompass infected animals (mostly dogs): Prevent infected dogs from entering ponds and other water sources Avoid feeding raw or undercooked fish or aquatic animals to dogs Part of “One Health” approach Summary slide 20 NTDs have been identified for control, elimination or eradication by the WHO Most NTDs are caused by: bacteria, protozoa, viruses, parasitic worms NTD impact is measured by mortality (deaths) and morbidity (DALYs) Many NTDs can be addressed by improving WASH (Water, Sanitation and Hygiene) Schistosomiasis and Dracunculiasis are NTDs caused by different species of parasitic worms Schistosomiasis is transmitted by snails and the parasite larvae burrow into human skin Dracunculiasis is transmitted by water fleas which are consumed from drinking contaminated water Dracunculiasis is on the verge of eradication using only low-tech WASH approaches: will be only the second human pathogen after smallpox to be eradicated Questions? 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