Waterborne diseases

• The Story of Legionnaires Disease

  • struck during a convention in the US
  • many attendees got infected by a rapid and rare pneumonia
  • the source was a new bacterium found in the cooling tower of the hotels air conditioning system
  • the bacteria was Legionella pneumophila
• What can occur if you have Legionnairres?

  • asymptomatic
  • Pontiac fever
  • Legionellosis
• Pontiac Fever -> mild cough, sore throat, headache
• Legionellosis -> a type a pneumonia that is most likely to affect elderly or immune impaired people. It can cause intestinal disorder, high fever, muscle aches, dry cough, chest and stomach pain
• the bacteria that causes Legionnaires is present in small numbers un natural waters, or in free-living protozoa and is heat and chlorine resistant
• L.pneumophila causes human infection via airborne droplets not from person person transmission
• V.cholerae

  • gram negative
  • curved rod
  • free living in water
  • adheres to normal microbiota
• What does V.cholerae cause?

  disease initiated when the ingested bacteria attach to epithelial cells of the small intestine. They begin to grow and release enterotoxin. This can lead to rice water stools (type of diarrhea) and mass water loss
• How is V.cholerae infection treated?

  intravenous or oral rehydration therapy (ORT) and liquid and electrolyte replacement therapy
• how is V.cholerae spread?

  Contaminated water or food
• Cholera has caused 7-8 world-wide pandemics
• V.cholerae is an aquatic bacterium that often lives in association with other aquatic biota
• What bacteria is associated with Typhoid fever?

  Salmonella Typhi
• S.typhi

  • gram negative
  • rod
  • is a member of enterobacteria
• How is Typhoid fever transmitted?

  can be via water, food borne, or with direct contact with infected individuals
• typhoid fever has been virtually eliminated in developed countries because of water treatment
• carrier state can be important with typhoid fever as a carrier shows no signs of illness
• What happens when you have Typhoid fever?

  is a systemic infection with sustained bacteremia (bacteria in blood) that causes high fever for several weeks. Headaches, constipation, diarrhea may also occur. and can often lead to perforation of the intestinal wall
• protozoans -> a group of single-celled eukaryotic microorganisms who are free-living or parasitic
• protozoans are a common cause of waterborne diseases in areas with regulated water supplies
• What are two types of diseases caused by protozoans?

  Cryptosporidiosis and Giardiasis
• Cryptosporidium life cycle

  • simple existence outside the body
  • the spore phase (oocyst) can survive for lengthy periods outside a host
  • complicated existence inside the body
  • in our body they reproduce within the intestinal epithelial cells
• What are the life stages of the Cryptosporidium?

  oocyst, trophozoite, sexual/asexual cycle, gametes, zygotes, thick/thin oocysts
• Giardiasis = beaver fever
• how is Giardia transmitted?

  via cysts through ingestion of feces contaminated water or food
• Giardia

  • flagellated protozoa
  • environmentally resistant cyst is infective agent
• what does Giardia cause?

  very bad diarrhea, cramps, nausea, weight loss, lactose intolerance, gas, vomiting
• how is Giardia treated?

  usually on its own or antibiotics
• Life cycle of Giardia

  • ingested cysts germinate in intestine
  • trophozoites grow on intestinal wall
• Waterborne viral diseases

  • many cause gastroenteritis
  • may cause eye, throat infections
  • hepatitis A and E
  • Polio which has essentially been eliminated
  • most can be neutralized via chlorination
• hep A (usually subclinical) and E (serious illness) can be within contaminated shellfish and transmitted enterically
• Ameoboid Waterborne diseases

  • Entamoeba histolytic is transmitted in water (cysts)
  • grow on in intestinal mucosal cells
  • amebic dysentery is invasive version
  • intestinal inflammation, ulceration, fever
  • invasion of liver, lung, brain
• Naegleria fowleri = brain eating amoeba
• How is N.fowleri transmitted?

  common in natural waters especially warm, immersing head in water while swimming allows flagellated form access to nasal passageway, movement across olfactory nerve allows access to brain
• meningoencephalitis

  • extensive hemorrhage, brain damage, death unless treated