Health and Sanitation Gwatt-Zentrum Tuesday, 23 August 2011 Peter - PowerPoint PPT Presentation

Epidemiology and Public Health Ecosystem Health Unit Sanitation Course SDC / HA Health and Sanitation Gwatt-Zentrum Tuesday, 23 August 2011 Peter Odermatt, PhD MPH

Excreta-related infections Viral diseases • Poliomyelitis Direct transmission: • Hepatitis A Excreta • viral diarrhoea Bacterial diseases • Cholera • Typhoid Man (finger, water, foodstuff, • Shigellosis kitchenware, flies, cockroaches, soil) • Bacterial diarrhoea Protozoal diseases • Amoebiasis • Giardiasis • Balantidiasis • Cryptosporidiasis Helminth diseases • Ascariasis, Hookworm, • Trichiurasis, Strongyloidiasis • Schistosomiasis Indirect transmission: • Taeniasis Excreta inter. host man Clonochiasis / Opisthorchiasis • 2

Virus Capsid, protein spikes, genetic material (DNA, RNA) Bacteria – Capsule (sticky, biofilm), Pili (attach), DNA, flagellum (moving); prokaryote Most bacteria beneficial (intestinal flora, degradation nutrients), spore forming, some pathogens 3

Micrococcus Staphylococcus aureus C orynebacterium sp. (Gram +) 4

Parasite: Protozoa (one cell), Helminths (worms), Ectoparasite (lice, flees, lice…), Schistosomiasis Giardia lamblia Hookworm Malaria (Plasmodium sp.) 5

Preventive measures : • sanitation • water  hygiene person, food … Context: • behaviour • environment • education • sociological and • economic status • health service 6 ( WHO, 1995 )

I. Excreta related diseases 7

Factors Affecting Transmission • General state of health, • Nutrition • Immunity ... 8

6 Excreta related transmission routes 9

Excreta related infections • I. Faecal-oral disease (non- bacterial): non-latent, low infection dose • Virus : hepatitis A • Protozoa : Entamoeba histolytica, Giardia lamblia , Cryptospridium sp. • Helminths (worms): Enterobiasis, Hymenolepiase 10

Trophozoite Entamoeba histolytica 11

Cysts Entamoeba histolytica 12

Amoebiase In colon: A. Non-invasive infection B. Intestinal disease C. Extra-intestinal disease 13

Intestinal abscess due to Entamoeba histolytica 14

Liver abscess due to Entamoeba histolytica 15

Entamoeba histolytica • protozoan dysenteria (diarrhoea with blood) • ± 10% global population infected (without symptoms) • ± 50 Mio sick & reach 100’000 deaths/year • Diagnosis • Examination of stool sample • Serodiagnostic and PCR (DNA search in stool) • Prophylaxis • Transmission fecal-oral • Food – and water-hygiene • Personal hygiene → sanitation 16

Excreta related infections • II. Faecal-oral bacterial diseases: non-latent, medium infection dose, moderately persistent, multiplication • diarrhoeas/dysenteries : Salmonellosis, Shighellosis, Campylobacter, Cholera , Escherichia coli diarrhoea 17

Cholera – Vibrio cholerae 18

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Vibrio spp. in shellfish, Abidjan 23

Prevalence of Vibrio spp. infection in shellfish, Abidjan 24

Vibrio species in shellfish, Abidjan 25

Excreta related infections • III. Soil Transmitted helminths : latent, persistent, no intermediate host • e.g. roundworm (Ascariasis), hookworm, … 26

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• latency • 200’000 eggs/day Ascaris life cycle 28

Hookworm life cycle 29

Hookworm • Affected group: children • « bloodsuckers » → anaemia, malnutrition • Latency • maturation in environment (moisture required) • Active penetration skin • protection (shoes …) • Treatment • efficient, cheap, safe (mass-treatment) 30

Excreta related infections • IV. Beef and pork tapeworm: latent, persistent, cow/pig intermediate host • Tapeworm (Taeniasis) - Cysticercosis 31

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Cysticercus (= larval stage) in intermediate host Head (Scolex) Segmented body Egg 33 Proglottide

34 Taenia solium Taenia saginata

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• Progrottid von Taenia saginata • > 15 Uterusästen 36

Proglottiden 37

38 Ei: Taenia sp . : 31 – 43 µm; gelb-braun

39 Finnen (= Cysticercus) in Schweinefleisch

Cysticercus von Taenia solium 40

Cysticercose Finne (Cysticercus) 41

42 Garcia et al. Lancet, 2003

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• Utilisation of human excreta • Proximity with pigs 45

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Excreta related infections • V. Water based helminths (worms) : latent, persistent, aquatic intermediate hosts – Schistosomiasis (Bilharzia) – Other flukes: liver fluke , intestinal flukes, lung fluke 47

Flukes (Trematodes) • adult worms 48 By J. Dick Maclean

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Prevalence of O. viverrini in schoolchildren in Lao PDR (2003) China Vietnam Thailand 50 Cambodia

Opisthorchis viverrini Metacercaria Life cycle 51

Opisthorchis viverrini : Metacercaria • Adult in fish • billiary tract, Cyproid fish: • length: 5-10 cm 52 Length: < 10 mm

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Schistosomiassis - Life Cycle Cercariae Fresh-water snail urine stool Adult parasite 55 Egg

snail : Neotricula aperta Rocky areas of Mekong river 56

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Reservoir host: Dog, porc, buffalo … 58

Control measures 59

Global distribution of schistosoma infections Low transmission (pre-elimination) High transmission From: Gryseels et al . Human schistosomiasis. Lancet 2006; 368: 1106–18 60

Excreta related infections • VI. Excreta related insect vectors: – Culex sp.- mosquito: Filariasis – Flies, cockroaches: transmission of I & II 61

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Eye infection: Trachoma • Chronic infection (conjunctiva & cornea) caused by Chlamydia trachomatis (bacteria)  Blindness • Transmission: person-person direct or indirect ( flies, hand, towel,…) • Prevention: regularly face + sanitation 63

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6 Excreta related transmission routes 65

Water related diseases I. Water- II. Water-washed borne (Water- scarce) Pathogens water quantity problem carried by water Faecal-oral Water transmission transmitted infectious disease IV. Water- III. Water- related based Pathogen Pathogen depends transmitted close/ on water animal/ near water plant 66 Mosquito-borne

Water related infections • I. Water-borne route : – Faecal-oral route of transmission (faecal contamination of water): • Person to person, animal to person, direct - indirect (water, food, towels …) – Intestinal tract disease: • Virus (Hepatitis A, Poliomyelitis), Bacteria ( Cholera , Shigellosis, …) , Protozoa (Crytosporidiosis, Amoebiasis , Giadiasis, …) 67

Water related infections • II. Water washed – water scarce: – Transmission due to low water quantity (washable infection) – A. Water washed: intestinal tract infection • Increase water availability: decrease faecal-oral transmission, e.g. cholera, bacillary dysentery, … – B. Water washed: skin infection / eye disease • bacterial skin diseases (scabies, …), eye infection (trachoma) • Transmission: not faecal-oral, not water-borne – C: Water washed: insect-borne • Louse-borne: typhus outbreak ( Rickettsia provazekii ) • Louse-borne relapsing fever ( Borrelia recurrentis) 68

Water related infections • III. Water-based route – Pathogens depend on water animals/plants (intermediate host) for transmission: • snails, fish, … – e.g. schistosomiasis, flukes, … 69

Water related infections • IV. Water related route of transmission – Spread by/near water – insect (mosquito)-borne disease – Development of insect bound to water: requirement of mosquito (ecology) defines distribution – Malaria : Anopheles sp. – Dengue haemorrhagic fever (DHF): Aedes aegypti 70

2-3 days 3-5 days pupe Larve in clean water (parallel to 50-200 eggs surface) 3-5 days Development of Anopheles mosquito adult egg → adult: 10-14 days biting position 71

Malaria life cycle Livercell Liver Mosquito Red cell Blood 72 Gametocyte

Malaria • Parasite: number 1 killer • 4 parasites: Plasmodium falciparum deadly (no reservoir) • Disease: from symptomless to acute disease & death (semi-immunity possible) • Treatment exists but: expensive, diagnosis not easy, under medical supervision, costly, … no vaccine • 42% of world population at risk • Ca. 500 million cases/year; ca 2 million death/year • Huge economic burden (hospital admission, disease periods, death, …) • Mosquito: Anopheles sp., large number of species • Ecology of Anopheles sp. v aries: Urban / rural; Plains, forest, mountains, …; Small – large water sites; Look closely at local condition 73

Malaria endemic countries (WHO, 2005) 74

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DHF : external bleeding 85