Chapter 3 Sanitation and public health What happens

Chapter 3. Sanitation and public health What happens in me if I am exposed (to different pathogens) Can we manage the risks? Cases and participatory approaches at different community levels How am I exposed? Which are the health targets and guidelines? From where do pathogens come? How can treatment and interventions minimize transmission? Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

3. 1 Exposure and effects in humans n tra s e as d e t t i sm ? d se e o s i p d x us e e o r i t a c ple infe o e e r p a n e w s? h o n w H e s g pen patho p a to t h a h W Learning objective: to become familiar with the most important pathogens found in water and sanitation systems, with the symptoms they cause and with their effect on individuals and populations. Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

DALYs – a general measure for health The Global Burden of Disease (GBD) Murray and Lopez, 1996 ¢ Disability Adjusted Life Years (DALY) l l ¢ morbidity: years lived with a disability mortality: years lost DALY (loss of healthy lived years) = n x t x S • n = number of affected persons • t = the duration of the health effect • S = measure of the severity of the health effect (mortality = 1) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Hypothetical example of DALYs Quality of life Index 1. 0 Remaining “disability” 0. 8 Acute (infectious) illness 0. 4 Years lost Premature death by 65 0 20 40 60 80 Age Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Leading DALYs in in the world 1990 & 2020 ”The sanitary revolution” - the most important medical milestone since 1840 !? (BMJ, 2007) Murray et al. (1996) Science 274: 740 -743 Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

DALYs attributable to risk factors Water and sanitation causes a major part (9%) of GBD, that largely could be prevented. (WHO, 2008) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Diseases contributing to the water-, sanitation- and hygiene-related disease burden PEM: protein-energy malnutrition (Adapted from WHO, 2008) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Global risk factors for disease and premature deaths (% of DALYs) Child underweight for age Unsafe water, sanitation, hygiene Low fruit & vegetable intake Zinc deficiency Iron deficiency anaemia Vitamin A deficiency Child underweight ~7. 9% Nutrition deficiencies ~7. 4% Water & sanitation ~3. 4% Total targeted by ”Ecosan”: ~18. 6% in Sub-Saharan Africa ~7. 6% 854 million chronically hungry 2 billion without food security FAO, 2006 Ref: Lopez et al. 2006. Global and regional burden of disease and risk factors; FAO, 2006

Infectious diseases ¢ high Frequency of infection World´s most common – caries ¢ severe Commonly existing diarrhoea and foodpoisoning low Unusual opportunistic infections in immunocompromised individuals Symptoms Life-threatening loss of water and salts (e. g. cholera) Mild diarrhoea (e. g. Staphylococcus food poisoning) mild None (e. g. polio) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

The field of Epidemiology ¢ Definitions l l (1) The study of the relationships of the various factors determining the frequency and distribution of diseases in a human community. (2) The field of medicine that attempts to determine the exact causes of localized outbreaks of disease. (Ologies & -Isms. Copyright 2008 The Gale Group, Inc. ) ¢ The start in the middle of the 19 th century l l Cholera epidemics in London - consumption of water implied an increased risk for disease (John Snow) Established that germs or bacteria cause infectious disease (Pasteur, 1857) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Occurrence of disease ¢ Prevalence l ¢ The number of cases in a defined population at a specified point in time Incidence l The number of new cases arising in a given period in a specified population Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Transmission of infectious agents ¢ Direct transmission l Touching l Kissing l Sexual intercourse l Other contact l Airborne, short distance via droplets, coughing, sneezing l Transfusion (blood) l Transplacental ¢ Indirect transmission l Vehicle-borne (contaminated food, water, towels, farm tools etc. ) l Vector-borne (insects, animals) l Airborne, long distance via dust and droplets l Parenteral (injections with contaminated syringes) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Consequences of exposure Exposure No infection No symptoms Infection Symptoms of disease Susceptible Recovered Death Immune Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Infectious dose ¢ ¢ ¢ Minimum infectious dose ID 50 Probability of infection l ¢ Dose-response curves Severity of disease depending on l l l Ingested dose The condition of the mechanical barrier The stability of the normal enteric flora Immunity The nutritional status of the individual Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Immunity – vulnerable groups http: //www. oldpeoplearefunny. com/pictures/ Vulnerable groups in society: ¢ The old (elderly) ¢ Infants ¢ Pregnant women ¢ Immunocompromised ¢ Malnourished These groups comprise about 20% of the general population and are growing Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Epidemiology - Definitions Pandemic: An epidemic (a sudden outbreak) that becomes very widespread and affects a whole region, a continent, or the world. By contrast: An epidemic affects more than the expected number of cases of disease occurring in a community or region during a given period of time. An endemic is present in a community at all times but in low frequency. (http: //www. medterms. com/script/main/art. asp? articlekey=4751) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Epidemic to endemic illnesses as detected by health surveillance Number of Cases Outbreak detected Threshold for detection for an outbreak Endemic rate Undetected outbreak Sporadic Hyperendemic Time Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Diarrhoea and sanitation ¢ ¢ Causes ~1/5 of deaths in children <5 years (1. 5 million) Has decreased, in 1980´s estimated 2/3 of deaths Less significant decrease in diarrhoeal disease in lowincome countries Infections related to water and sanitation ¢ ¢ 4. 1% of the total DALY 88% of the burden attributable to unsafe water supply, sanitation and hygiene Improved sanitation can reduce diarrhoea by ~32% 391 million cases averted if MDG target met Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Regional differences in average health burdens from diarrhoeal diseases (SSA) Source: Our Planet Current annual diarrhea cases in SSA: 1. 2 billion which lead to 769, 000 dead children, mostly under 5 years Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Diarrhoeal diseases – Outbreaks related to water and sanitation ¢ Cholera l l l ¢ Typhoid fever l ¢ 36 reported outbreaks from 2006 -2009 (WHO) Risk during flooding “Natural environmental” spread Also endemic Shigellosis Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Cholera epidemic ¢ ¢ ¢ Acute watery diarrhoea, very deadly without rapid treatment Affects adults as much as children, especially informal caretakers High political profile : can be used as a political leverage ¢ Characteristics for cholera outbreaks l l l ¢ high attack rate low mortality economic and social burden Factors of spread l l density of population transportation facilities living conditions environmental reservoirs Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Consequences of cholera outbreaks Cholera Outbreak Social Burden Health impact Health Care Facilities overwhelmed More supplies, more staff “Psychological” impact Economic burden Panic Media Political impact Who is responsible? Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Classification of communicable diseases related to water and sanitation § Water-borne diseases: caused by the ingestion of water contaminated by human or animal faeces or urine containing pathogenic bacteria or viruses or parasites; include cholera, typhoid, amoebic and bacillary dysentery and other diarrhoeal diseases. § Water-washed diseases: caused by poor personal hygiene and skin or eye contact with contaminated water; include scabies, trachoma and flea, lice and tick-borne diseases. § Water-based diseases: caused by parasites found in intermediate organisms living in water; include dracunculiasis, schistosomiasis and other helminths. § (Other) Water-related diseases: caused by insect vectors which breed in water; include dengue, filariasis, malaria, onchocerciasis, trypanosomiasis and yellow fever. (WHO, 1996) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Waterborne pathogens – important in water and sanitation systems ¢ Bacteria l l l ¢ The leading cause of gastrointestinal infections according to surveillance systems Salmonella, Shigella, Campylobacter, E. coli (toxinprod. ) EHEC Legionella Opportunistic e. g. Aeromonas hydrophila Virus l l Probably the cause of many outbreaks, difficult to detect Noroviruses (Calici-, Norwalk like), rotavirus, hepatitis A Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Waterborne pathogens (con´t) Waterborne pathogens – important in water and sanitation systems ¢ Protozoa l l ¢ Complicated life cycles with resistant stages (chlorine) Giardia, Cryptosporidium, Entamoeba Low infectious dose In Milwaukee (USA) in 1993, 400, 000 were infected by Cryptosporidium Helminths (worms) l l l Varying transmission routes, e. g. soil borne Ascaris, Trichuris, Schistosoma (bilharzia), hookworm A large problem in many developing countries Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Shigella Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Salmonella infection – Salmonellosis and Typhoid fever Salmonellosis – diarrhea, fever, and abdominal cramps ¢ ¢ Caused by a variety of serotypes, e. g. Salmonella Typhimurium and Salmonella Enteridis Foods contaminated with animal faeces ¢ ¢ Animal origin (meat, poultry, eggs), vegetables Pets – hand washing important Paratyphoid and Typhoid fever - fever and other symptoms ¢ ¢ Life threatening Caused by Salmonella Typhi Transmitted by contaminated food or water More common in areas with low sanitary standards Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Schistosoma ¢ ¢ ¢ Also known as bilharzia 200 million people are infected worldwide Variety of symptoms Freshwater contaminated by urine or faeces Life-cycle requires specific snail as host Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Viral gastroenteritis ¢ What is viral gastroenteritis? l l l ¢ Inflammation of the stomach and small or large intestines Results in vomiting and/or diarrhoea Often called ”stomach flu" What causes viral gastroenteritis? l l Not caused by the influenza viruses Caused by many different viruses e. g. rotaviruses, adenoviruses, caliciviruses, astroviruses, Norwalk virus, and a group of Norwalklike viruses (later called calicivirus, norovirus) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Rotavirus ¢ ¢ ¢ Rotavirus is the most common cause of severe diarrhea among children Globally, rotavirus is estimated to cause 527, 000 deaths in children annually Vomiting and watery diarrhea for 3 - 8 days, and fever and abdominal pain occur frequently Immunity after infection is incomplete Vaccination possible but not widespread (http: //www. cdc. gov/rotavirus) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

NOROVIRUS Norovirus ¢ ¢ Previously called calicivirus or Norwalk (Like) viruses Transmission l l l Person-to-person Food-borne Waterborne Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Ascaris ¢ ¢ ¢ Ascaris lumbricoides is one of the largest and most common parasites found in humans It is estimated that 10% of the world's population is infected with this nematode The adult worms live in the small intestine and eggs are passed in the feces - a single female can produce up to 200, 000 eggs each day Ascaris lumbricoides, fertilized egg. The egg is covered with a thick shell that appears lumpy approximate size = 65 µm in length. The adult worm. Adult females of this species can measure up to 18 inches long (males are generally shorter). Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Ascaris (con´t) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Cryptosporidium ¢ ¢ Cryptosporidium is a small parasite, about 3 -5 µm. It lives on the surface of the cells lining the small intestine and oocysts are passed in the feces. Transmission of the infection occurs via the oocysts. Many human infections have been traced to the contamination of drinking water with oocysts from agricultural "run-off" (i. e. , drainage from pastures), so it is considered a zoonosis. Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Cryptosporidium (con´t) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Giardia ¢ ¢ Giardia intestinalis (also known as Giardia lamblia or Giardia duodenalis soil, food, or water that has been contaminated with feces Common in both developing and developed areas Giardia lamblia trophozoites live in the small intestine of the host. Cysts, which are resistant to adverse environmental conditions, are passed in the feces of an infected host, and the next host is infected when it ingests cysts in food or water contaminated with feces. ¢ The trophozoites adhere closely to the lining of the small intestine, and in heavy infections much of the lining can be covered with trophozoites. The giardiasis symptoms range from none (in light infections) to severe, chronic diarrhea (in heavy infections). Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Features of some gastrointestinal infections (Westrell, 2004) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Emerging pathogens ¢ Emerging diseases l l ¢ Zoonoses l l ¢ Newly recognized or Increasing importance Many emerging pathogens of zoonotic origin Animal faeces contaminate water Climate change l l Increased risks related to water and sanitation Affects food-production Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Protozoa and helminths in faecal material ¢ ¢ Picture provided by Teddy Gounden ¢ Faecal samples from 120 urine-diverting latrines in Kwa. Zulu-Natal, South Africa Varying features – water-filled to dry (normal) Analysing for presence of: l parasitic protozoa Giardia and Cryptosporidium l helminths Ascaris lumbricoides, Trichuris trichiura and Taenia spp (Trönnberg et al. , 2010) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden

Protozoa and helminths in faecal material ¢ Parasites l l ¢ Helminths l l l ¢ ¢ 54% positive for Giardia 21% positive for Cryptosporidium 59% Ascaris lumbricoides 48% Trichuris trichiura 18% Taenia spp In 73% of the 120 household toilets, one or several types of helminths were found Prevalence by family (at least one member infected) Supports theory of high prevalence in certain areas Treatment needed before use of faeces (Trönnberg et al. , 2010) Caroline Schönning, Swedish Institute for Communicable Disease Control, Solna, Sweden