Schistosomiasis Alan Fenwick

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1 Professor Department of Infectious Disease Epidemiology, Faculty of Medicine Imperial College, London 1 (Bilharzia) is caused by trematode worms which inhabit the blood vessels around the bladder or in the mesentery 2 Species in humans S. haematobium urinary Africa only no animal reservoir Schistosoma mansoni intestinal Africa and South America maybe rodents and primates S. japonicum intestinal once the scourge of Japan and China now restricted zoonotic S. intercalatum (Africa) S. mekongi (Asia) 3 1

2 The life cycle Human host transmission cycle Snail host 4 Widespread distribution Once widespread in China and Brazil, control has reduced the prevalence and sickness in Asia and South America However today an estimated 200 million are still infected with schistosomiasis, most of them in Africa most of them are the poorest of the poor 5 Anyone can get infected if they bathe in fresh water in Africa 6 2

3 The disease is man-made The Blue Nile dam in 1920 s caused a massive outbreak of schistosomiasis and malaria in Sudan The Dams on the Volta and Senegal rivers in the 1980s caused epidemics of S. haematobium in Ghana and S. mansoni in Senegal The Aswan High Dam changed the Egyptian Nile Delta for ever and created habitats for S. mansoni snail hosts 7 Bloody urine caused by schistosomiasis 8 An extreme case of S. mansoni in Uganda 9 3

4 The disease burden due to schistosomiasis is understated Objective morbidity (hepatosplenomegaly, hematuria) is only the tip of the disease/disability iceberg Pain, diarrhea, undernutrition, and anemia are clearly associated with infection, worse with heavier infection, and reversible, at least in part, with specific therapy 10 What will a doctor see? For a physician individual cases may be hard to diagnose S. haematobium blood in urine has to have originated in Africa S. japonicum has to have originated in Asia S. mansoni intestinal symptoms - South America, Caribbean, Africa, Middle east 11 Questions to ask Has your patient been exposed? Most schistosomiasis transmission sites would not be visited by Westerners Swimming in Lake Malawi Fishing in lakes and streams Bathed in fresh water in an endemic area Camped in areas where no piped water 12 4

5 Water contact in Mali during collective fishing 13 Diagnosis and treatment Stool examination for S. mansoni eggs and S. japonicum eggs Urine examination test for blood in urine Microscope examination for eggs of S. haematobium filtration method Ultrasound examination of liver and bladder 14 is a disease of the rural poor A disease of snails transmitted by small boys Children swimming in surface water in hot climates Farmers using irrigation Ladies doing domestic washing in lakes, ponds, canals and streams A disease of crowding, poor sanitation and man made snail habitats 15 5

6 Sampling For mapping and predictive purposes at each school, aged cohorts each of 30 children 6, 7, 8, and 11 years are enrolled (male: female ratio, 1:1) For monitoring the sample sizes have been calculated using an expected reduction in mean intensity of 60%; A drop-out rate of 40% over the monitoring period was also allowed; The sample size was estimated to 300 individuals per school e.g.brooker S, Whawell S, Kabatereine N, Fenwick A, Anderson RM (2004) Trends Parasitoll 16 Data collection and measurements Heights/weights Liver/spleen palpations Serology Questionnaires Kato-Katz/Filtration stool and urine analysis 17 Evaluation and application of ultrasound morbidity indicators for schistosomiasis in the context of large-scale programmes 18 6

7 How to control schistosomiasis Human host Chemotherapy Praziquantel Prevent exposure Sanitation transmission cycle Snail control environmental Snail control Chemicals Snail host 19 Early large scale control projects Egypt 49 (molluscicides) 1960 s Fayoum (molluscicides and ambilhar) 1970 s GTZ in Cameroon and Mali (molluscicides and praziquantel) 1980 s Blue Nile Health Project (molluscicides and praziquantel) 1980 s St Lucia (all interventions) 1980 s Lake Volta (praziquantel) 1990 s Egypt national praziquantel 1990 s 20 control in the world 2002 almost eradicated ongoing large-scale control programmes limited or no control 21 7

8 SCI control programmes in Africa Expanded from Burkina Faso Mali Niger Zambia Uganda Tanzania Rwanda SCI/Geneva Global Burundi SCI/Geneva Global 22 Gu Guinea SL Sierra Leone Li Liberia CI Cote d Ivoire BF-Burkina Faso Countries currently in need of further support for their control programmes West African countries Angola Equatorial Benin Guinea Cameroon Gabon Central African Ghana Republic Guinea Chad Sierra Leone Congo Togo Cote d Ivoire Mali Niger Chad BF Sudan Gu Nigeria SL Ethiopia Li CI CAR Cameroon Ghana-Togo- Uganda Congo Benin Gabon Kenya DRC Tanzania Angola Zambia Zim Namibia Botswana Ml Mo East African countries Botswana Lesotho Sudan Djibouti Madagascar Swaziland DRC Malawi Tanzania Ethiopia Mozambique Uganda Kenya Namibia Zimbabwe Somalia Somalia Madagascar Le Lesotho Ml Malawi Mo - Mozambique Sz Swaziland Zim - Zimbabwe Countries in red require partial support 23 Risk maps for Hookworm and Schistosoma mansoni 24 8

9 WHO s target Regular treatment to at least 75% of all school-age children at risk of morbidity for schistosomiasis and soil-transmitted helminth infections by 2010 (World Health Assembly 2001) 25 Soil transmitted helminth infections Ascariasis, trichuriasis, hookworm Ascariasis Trichuriasis Hookworm 807 million cases 604 million cases 576 million cases 26 MDA coverage 2008 STH/Schisto 10% 90% Lymphatic Filariasis 38% 63% Onchocerciasis 44% 56% 0% 20% 40% 60% 80% 100% At risk population treated Untreated 27 9

10 Praziquantel Praziquantel is efficient and safe It is now off-patent - so significant price cuts In 1988 when praziquantel first came to market, the price was approximately $1 per tablet ($4 for an adult course) In 2006 several pharmaceutical companies sell praziquantel for less then 8 cents a tablet That is 92% cheaper!!! But what does it cost in a pharmacy for an individual in UK or USA??? 28 one essential tool The Height Pole instead of weighing the children 29 The schistosomiasis control initiative SCI was established in 2002 at Imperial College with a grant from Bill and Melinda Gates Foundation SCI has a current separate grant for integration of NTDs SCI started by assisting 6 countries to implement schistosomiasis and STH control pledging to reach 20 million people 30 10

11 SCI control programmes in Africa Burkina Faso Mali Niger Zambia Uganda Tanzania Rwanda SCI/Geneva Global Burundi SCI/Geneva Global 31 Preparation milestones Country National plans prepared Country surveillance plans prepared For selected countries Memorandum of Understanding agreed Baseline data plan prepared Country technical capability reviewed Drug availability reviewed Health education materials reviewed Training schedule prepared 32 Implementation and monitoring For selected countries Training of district health/education officers Baseline data collected Drug procurement underway Health education materials prepared Pilot phase implementation completed Process evaluation by district 6 and 12 month parasitology follow ups Phase two plans prepared and implemented Countries commit funds and seek additional donations 33 11

12 Ministries of Health with SCI support Number of Treatments (millions) m 26 m 12 m 3 m /3 2003/4 2004/5 2005/6 2006/7 SCI Treatment Years Egypt the success story 36 12

13 Prevalence and intensity are reduced Dramatic reductions in intensity have been observed 500 Mean Intensity (EPG) Lake Albert Albert Nile Lake Victoria Baseline Follow-up Year 1 Follow-up Year 2 Time Uganda children Percentage (%) Baseline 90 Year Negative: Lightly infected: Heavily infected: 0 <50 >=50 Classes of intensity (e/10ml) Burkina Faso children 37 Burkina Faso S. haematobium by directorate S. Haematobium prevalence for n = 542 children by Regional Health Directorate during 4 years of study Prevalence (%) BOUCLE MOUHOUN (n = 164) NORD (n = 203) SAHEL (n = 135) SUD OUEST (n = 40) 0 Baseline Follow-up year 1 Follow-up year 2 Follow-up year 3 Time 38 Burkina Faso Improvement in haemoglobin 12.5 Mean Hb counts for n = 562 children during 4 years of study (longitudinal data) Mean Hb counts (g/dl) Baseline Follow-up year 1 Follow-up year 2 Follow-up year 3 Time 39 13

14 Burkina Faso Reduction in anaemia Overall prevalence of anemia for n = 562 children during 4 years of study (longitudinal data) Prevalence (%) Baseline Follow-up year 1 Follow-up year 2 Follow-up year 3 Time 40 The United Nations Millennium Development Goals (MDGs) we could speed progress towards most of the MDG s 1. Eradicate extreme poverty and hunger 2. Achieve universal primary education 3. Promote gender equality and empower women 4. Reduce child mortality 5. Improve maternal health 6. Combat HIV/AIDS, malaria and other diseases. 7. Ensure environmental sustainability 8. Develop a global partnership for development NTDs are included in other diseases 41 Low cost of interventions Range of treatment costs per person per year HIV/AIDS TB Malaria 'Rapid Impact' Package <$0.50 for packaged intervention delivery costs for donated drugs Cost per patient treatment per year (US dollars) 42 14

15 A great opportunity We are in a position to offer treatment and improve the quality of life for millions of school aged children in Sub Saharan Africa, and protect them for the future from the terrible consequences of the Neglected Tropical Diseases USAID and Bill Gates have risen to the challenge with grants of $100 million each 43 Optimism and pessimism Now is the time Improved quality of life by treating schistosomiasis and STH Improved water and sanitation Better health education 44 Acknowledgements The Pharmaceutical Industry for praziquantel The Bill and Melinda Gates Foundation, USAID and Geneva Global for funds for control The Department for International Development, UK also for funds for control 45 15

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