1. Waterborne Pathogens: Parasites February 23 rd -25 th, 2010

2. Parasitic pathogens in water Enteric and non-enteric diseases Ingestion of contaminated water Contact with contaminated water Complicated life cycles taking place in water and the human body with intermediate hosts

3. Categories of waterborne parasites Diseases contracted by ingestion of contaminated water Cryptosporidium Entamoeba Guinea worm disease Diseases contracted by contact with contaminated water Naegleria Schistosomiasis

4. Cryptosporidiosis Cryptosporidium parvum Protozoan parasite Fecal-oral transmission Humans and cattle are reservoirs Contamination of water sources from cattle fields Infectious stage is the extremely resistant environmental stage (oocyst) Resistant to chlorine disinfection Diarrheal disease that can become chronic in immunosuppressed people

5. Cryptosporidiosis Diagnosis through immunofluorescent staining and microscopy

7. Amoebiasis Entamoeba histolytica Amoebic dysentery Fecal-oral transmission Infectious stage is the resistant environmental stage (cyst) Humans are reservoir Disease is ubiquitous in areas of poor sanitation

8. Amoebiasis Diagnosis via microscopy (fecal specimen)

10. Naegleria Naegleria fowleri Ubiquitous free-living amoeba Reservoir: warm surface freshwaters Primary amoebic meningoencephalitis A common organism, but a rare disease Infection by crawling up your nose into your brain Treatment with amphotericin B, but survival rates are poor

11. Naegleria Diagnosis by microscopy of spinal fluid

13. Schistosomiasis Genus Schistosoma Species mansoni, japonicum, and haematobiun Blood flukes (parasitic worms) Burden of disease is from chronic infection Damage caused by eggs deposited in tissue –Liver damage –Urinary tract damage

14. Schistosomiasis Humans are the main reservoir Excrete eggs in feces Important intermediate host: snails Schistosomes live in the snail in freshwater Infection from contact with water Infectious stage is the cercariae They leave the snail and penetrate skin Migrate through the bloodstream to organs

15. Schistosomiasis Diagnosis by microscopy of eggs in stool or biopsy specimens

17. Schistosomiasis control Prevent contamination of water with adequate sanitation and disposal of feces Kill the cercariae by disinfection Kill the intermediate host (molluscicides) Drug treatment –Praziquantel –Treatment of individuals who are infected –Mass drug treatment of communities as a preventative measure

18. Guinea worm disease Dracunculus medinensis Nematode (worm) Humans are the reservoir Intermediate host: small copepods that live free in freshwater

19. Guinea Worm disease Worm larvae infect copepods People ingest copepods, esp. when they drink stagnant water Larvae migrate from the stomach through the body Worms erupt though the skin Putting affected areas of the body into water releases the larvae to restart the cycle Burden of disease from secondary bacterial infections of skin lesions

20. Guinea Worm disease Diagnosis by microscopy of the larvae or seeing the worm crawl out of the skin

22. Guinea Worm control Target of a fairly successful eradication campaign Endemic only in Sudan, Ghana, Mali, Ethiopia No effective drug treatment Control by filtering water to remove the copepods Digging wells for safer water Kill the copepods

23. Control of waterborne parasites Drinking water: Prevention of water contamination –ADEQUATE SANITATION Barrier methods –Treatment trains –Filtration –Most parasites are quite resistant to disinfection

24. Control of waterborne parasites Control of intermediate hosts (snails, copepods) Eliminating human infection to prevent further spread into the environment Preventing contact with high-risk sources