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Waterborne infection

Waterborne infection. In the U.S. the number of disease outbreaks due to drinking or recreational water contamination is relatively low Worldwide, lack of adequate water treatment facilities and access to clean water contribute significantly to the spread of infectious diseases.

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Waterborne infection

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  1. Waterborne infection • In the U.S. the number of disease outbreaks due to drinking or recreational water contamination is relatively low • Worldwide, lack of adequate water treatment facilities and access to clean water contribute significantly to the spread of infectious diseases

  2. Waterborne infection: Cholera • Cholera • Severe diarrheal disease • Caused by Vibriocholerae • Typically transmitted through ingestion of contaminated water • Largely restricted to developing countries • Endemic in Africa, Southeast Asia, the Indian subcontinent, and Central and South America • Can be controlled by application of water treatment

  3. Waterborne infection: Cholera • Pathogenesis • V. cholerae attaches to epithelial cells in the small intestine where it grows and releases enterotoxin • This enterotoxin causes severe diarrhea • Can result in dehydration and death unless treated • Diagnosis • Presence of V. cholerae bacilli in the “rice water” stools of patients

  4. Waterborne infection: Cholera • Prevention • Immunization not recommended • Public health measures are very important • Treatment • Treated with oral rehydration and electrolyte replacement therapy

  5. Waterborne infection: Giardiasis and cryptosporidiosis • Cryptosporidium parvum causes cryptosporidiosis • These organisms are found in nearly all surface waters and are highly resistant to chlorine due to cyst formation

  6. Waterborne infection: Giardiasis • Giardiasis • An acute gastroenteritis • Caused by a flagellated protist(Giardiaintestinalis) that is usually transmitted to humans in fecally contaminated water • The protist cells produce a resting stage (cyst) that is resistant to desiccation and chemical disinfection • Following ingestion, cysts germinate and attach to the intestinal wall causing symptoms of infection • Many individuals exhibit no symptoms and can act as carriers Cyst

  7. Waterborne infection: Cryptosporidiosis • Cryptosporidiosis • An acute gastroenteritis • Caused by a protist(Cryptosporidium parvum) that lives as a parasite in warm-blooded animals • Produces thick-walled, infective cells (oocysts) that are shed in high numbers in the feces of infected animals • The oocysts are transmitted in fecally contaminated water • Oocysts are highly resistant to chlorine and UV radiation

  8. Waterborne infection: Legionellosis (Legionnairs’ disease) • Legionellosis • Caused by Legionellapneumophilia • Normally transmitted in aerosols • Common in terrestrial and aquatic habitats • Relatively resistant to heating and chlorination • Common in cooling towers and evaporative condensers of large air conditioning systems • The pathogen grows in the water and is disseminated in humidified aerosols • Infection is not spread from person to person

  9. Waterborne infection: Legionellosis (Legionnairs’ disease) • The prevalence of legionellosis is increasing and infections are often underreported • Treatment with antibiotics is effective • Prevention can be accomplished by improving maintenance and design of water-dependent cooling and heating systems and water delivery systems Incidence of Legionnaires’ Disease in the United States

  10. Waterborne infection: Typhoid fever • Typhoid fever • Caused by Salmonella typhi • Virtually eliminated in developed countries due to water treatment • Typhoid fever is characterized by a slowly progressive fever as high as 40 °C, profuse sweating, gastroenteritis, and nonbloody diarrhea. Less commonly, a rash of flat, rose-colored spots may appear

  11. Waterborne infection: Other waterborne diseases • Viruses can also be transmitted in water and cause human disease • e.g., enteroviruses such as poliovirus, norovirus, and hepatitis A are shed into water in feces • Viruses can survive in water for relatively long periods but are inactivated by disinfection with chlorine

  12. Waterborne infection: Other waterborne diseases • Entamoebahistolytica • A common pathogenic protist transmitted to humans primarily through contaminated water and sometimes food • Anaerobic and produces resistant cysts • Infection can be asymptomatic or lead to diarrhea and/or dysentery • If untreated, invasive cells can invade the liver and occasionally the lungs and brain • Amoebicidal drugs are not universally effective

  13. Waterborne infection: Other waterborne diseases • Naegleriafowleri • A free-living amoeba found in soil and water runoff that can also cause amoebiasis • Infections usually result from swimming in warm, soil-contaminated water sources (e.g., hot springs or lakes) • Enters the human body through the nose and burrows directly into the brain, causing extensive hemorrhage and brain damage (meningoencephalitis) • Drug treatment is effective if infections are identified early Trophozoites of Naegleriafowleri in brain tissue

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