Water-Borne Diseases Flashcards
Waterborne microorganisms can be
viruses, bacteria, protozoa, and harmful algae.
Harmful algae are
naturally occurring phytoplankton
carry toxins and accumulate in shell fish
Cause shellfish poising, respiratory issues, harm marine life.
Ex: DINO: karenia brevis
diatoms, cyano
How do they get into the water?
overland flow: agriculture, wild animals, urban runoff, sewage effluent, goes into rivers/storm drains and straight into the ocean.
Groundwater flow; septic tanks, sewage pipes, into canals, rivers.
Boaters
Naturally-occurring: vibrio species, phytoplankton.
Harmful Algal Blooms
Algal bloom: historically a bloom= increase in pop
harmful: discolored water, anoxia
toxic and harmful (oxygen depletion, gill destruction)
What species was involved in the gulf of mexico menace? and what happened?
Karenia Brevis - produced lipophilic brevetoxins
Symptoms in humans - shellfish poisoning- diarrhea,chills, headache, weakness, pain, double vision.
causes massive fish kills, blooms 20 of last 57 yes, 1991-2009
What were the mortalities of wildlife?
All of kinds of fish, birds, reptiles, mammals, no humans
How to detect hazardous microbes?
fecal pollution indications, monitor harmful algae counts, monitor shellfish for toxins,
close water to swimming/shellfish harvest is levels too high.
What is the enterococci bacteria limit for recreational contact? fecal coliform?
35/100 ml
14/100 ml
Why use indicators of pollution?
Pathogens are difficult to measure, lower concentrations, expensive time consuming, technically difficult analyses
Bacterial indicators indicate? and are?
Fecal colifom, E. coli, enterococci,
Present when pathogens are present, less expsensive, less expertise needed.
Enterococci are good indicators for fecal pollution why?
they have a greater correlation with swimming associated gastrointestinal illness
higher tolerance for salt and are useful indicators in marine environemtns
Fecal oral tranmission
microorganims tranmited in water that grow in intestines and leave the body in fecfes, water is then polluted by feces/sweage and consumed by the host
Cholera is what? How is it transmitted/ controlled? where Is it commonly found?
Caused by vibrio cholerae, typically transmitted through ingestion of contaminated water,
Large ID of cells in water
Largely restricted to developing countries
endemic in Africa and Asia, and Haiti. can be controlled by application of water treatment.
Explain the pathogenesis of cholera
V. cholarae attached to epithelial cells in the small intestine where it grows and releases enterotoxin
this enterotoxin dehydrates and cayses diarrhea.
Diagnosis, prevention and treatment of cholera
Rice water stools
public health measures
oral rehydration/electrolyte replacement
V. Vulnificus infection, where does it occur?
naturally occurs in warm coastal waters
thousands of infections each year, from shell fish
exposure due to shell fish consumption or wound infection.
shell fish/raw oystres
in 24hrs diarrhea vomiting fever
wound infection: seawater/raw shell fish drippings into cut.
Can be fatal to immunocompromised. reness swelling decreased blood pressure.
Giardia intestinalis causes
causes giardiasis, an acute gastroenteritis.
What are giardia? what do they have? what type of protist?
They are diplomonads- have two nuclei of equal size
Have mitosomes-degrenerate mitochondria.
Flagellated protist- transmitted to humans in fecally contaminated water
What is giardiasis also known as?
beaver fever.
the protist cell of giardisis does what?
produces a resting stage (cyst) that is resistant to desiccation and chemical disinfection.
After ingestion, cysts germinate and attach to the intestinal wall, causing infection symtpoms
what are the symptoms of giardisis
Foul smelling poop, cramps, sulfur burps.
many are asymtpmatic
What is cryptosporidiosis and what causes it? Explain it.
cryptospridium parvum.
it is found in surface freshwater and is highly resistant to chorline because it forms cysts.
its a protist that lives as a parasite in warm-blooded animals and produces thick-walled infective cells (oocysts) that are shed in high numbers.
What are the symptoms of cryptospordisis
usually a self-limiting mild diarrhea
Legionella pneumophillia
causes legionellosis: respiratory disease.
can develop into pneumonia.
normally transmitted in aerosols and is a gram-negative bacteria with complex nutritional requirements.
common in aquatic/terrestrial habitats.
relatively resistant to heating and chlorination.
Where else is legionellosis is common?
in cooling towers and evaportative condensers
pathogens grow in water and is put ou via humidifers and hot tubs/ showers. infection is NOT spread from person to person, it is not contagious.
Typhoid Fever
S. typhi that causes typhoid fever and has been virtually eliminated in developed countries due to water treatment. easily killed by chloorination.
humans only host and are obligate parasite
Enterobacteria
gram neg rods that are facultative and are S. typhi on lactose fermentators.
Symptoms of typhoid fever
affects roughly 17 mil people and are fever, headache, diahreea, appetite loss, and has high virulence
Explain virulence of typhoid fever
VI antigen thought to increase virulence and invasin that allows nonphagocytic cells to take up bacterium.
Inhibits the oxidative burst of leukocytes.
Viruses can survive in what but
are inactivated by disinfection with chorine. this is a major concern for well contamination also
Explain enteroviruses
SS + RNA
polio, coxsackie, cho
non-polio= mild respiratory, hand foot and mouth disease and hemmorghgic conjunctivitis and meningitis
Most common cause of viral gastroenteritis
norovirus (calicivirus)
Usually non severe, self limiting.
only incomplete and temporary immunity given
hepatitis A
Picornavirus family and has long incubation (2-6 wks)
vaccine program is effective and also prevent by hygiene and sanitation, effective vaccine program and prevent by cleaning and good hygiene
Explain entamoeba histolytic
type of protist, contamination, resistance, symptoms, treatment
common protist that is pathogenic and transmitted to humans primarily through contimated water/ food
produces resistant cysts and is anarobic
Infection can be asymptomatic or lead to diarrhea and or dysentery (inflammation, fever, blood, mucus)
Amoebidical drugs are not universally effective
Naegleria fowleri
explain what is it and how infections occur and how it enters the body
not gastrointestinal illness like the others
- a free-living amoba found in soil and water runoff that can infect brain
- infections usually result from swimming in warm, sedmient rich after sources
-enters the human body through the nose burrows and directly into the brain causing extensive hemmorhage and brain damage.
Naegleria fowleri is
RARE but 95% mortality
Food poisoning
- also called food intoxication
- disease that results from ingestion of foods containing preformed microbial toxins
The microorganisms for food poisoning don’t
have to grow in host or be alive to produce the toxins
Microbial sampling is for food borne disease
pathogenic microbes can be present in fresh foods.
rapid detection methods have been developed
cultivation techniques may also be used to confirm link to particular pathogen/food sources.
Food poisioning is often caused by
toxins produced by S. Aureus
S. Aureus
can grow on common foods and some strains produce heat-stable enterotoxins
Gasttroenteritis occurs
within a few hours
Enterotoxins of s. aureus
classified as superantigens produce large T cell response and inflammatory response.
Usually self-limitng
can be detected by ELISA
S. aureus illness soley due to
Enterotoxin A
the most common other than B/C
Clostridial food poisoning is caused by
C. perfringens and C. botulinum,
produces endospores that may not be killed during cooking or canning
? is most commonly reported form of food poisioning
C. perfringens large numbers of cells must be ingested grow mostly on meats unfridgerated 7-15 hours after consumption upon sporutlation elisa test to detect toxin
Botulism, what causes it and what is destroyed by?
easy neurotoxin destroyed by heat rare 25% fatality home-prepared foods are the most common source
Salmonellosis
caused by foodborne salmonella infection
S. enterica the species but serotype more informative diagnostically
-40,000-50,000
food production and animals may harbor salmonella uncooked eggs
For intestinal infection, antibiotics
for septic or typhoid infections
indv. may be asymptomatic
E. Coli
non-pathogenic
few produce potent enterotoxins upon growth.
ENTEROhemorrhaggic produce verotoxin similar to shiga toxin
Verotoxin
causes bloody diarrhea and kidney failure
potential waterborne pathogen as well
Camplyobacter
MOST COMMON Bacterial foodborne infections in U.S.
more than 2,000,000 cases
transmitted via contaminated food
transmitted to humans pork shellfish and ingestion c
Listeriosis
L. Monocytogenes is cause for listeriosis
-May lead to bacteria and meningitis
psychotolerant and is an intracellular pathogen
-uptake of the pathogen by phagocytes results in the growth
dangerous to unborn fetus, probably common
mortality rate is 20%
Viruses
the largest number of annual foodborne infections are thought to be caused by viruses
Protist
can be spread in foods contaminated by fecal matter in untreated water use to wash, irrigate, or spray crops.
Examples:
cyclospora cayetanensis causes gastroenteritis toxoplasma gondii worms techiniella spiralis anisakis simplex
Prions
Proteins that adopt novel conformations that inhibit normal protein function and cause degeneration of neural tissue
-new variant cruezfeldt
