Waterborne diseases

Question 1

What are 4 important water-borne pathogenes?

Answer 1

1. e. coli
2. campylobacter
3. vibrio cholera
4. cryptosporidium

Question 2

What are water-borne diseases?

Answer 2

diseases caused by ingestion of contaminated water

Question 3

What are water washed diseases?

Answer 3

diseases caused by poor personal hygiene and skin and eye contact

Question 4

What are water-based diseases?

Answer 4

diseases caused by parasites found in intermediate oragnisms living in contaminated water

Question 5

What are water-vector related diseases

Answer 5

caused by insect vectors esp mosquitos that breed or feed near contaminated water

Question 6

What are 12 factors causing re-emergence of zoonotic pathogens

Answer 6

1. changing patterns of water use
2. population factors
3. travel, recreation
4. water scarcity, climate change, weather events
5. conflict, disaster
6. increased urbanization, colonizatino
7. increased demand for animal protein, fresh vegetables
8. increased antimicrobial used
9. concentrated animal husbandry, feedlots
10. domestic pet density
11. economic disturbance
12. international trade patterns

Question 7

Explain walkerton ontario 2000 scenario

Answer 7

widespread illness, bloody diarrhea/hemorrhagic uremic syndrome
7 died
PFGE used to compare strains
pulsenet canada used
traecd back to nearby cattle farm–not doing anything wrong
biofilm formation on the copper line

Question 8

What were reported causes of the walkerton outbreak?

Answer 8

1. ecological important boundaries don’t match political ones
2. contaminated well located in area engineers advised against
3. change of responsibility with improper training
4. unclear roles and responsibilities
5. heavy rainfall

Question 9

How is risk of O157:H7 from animal waste minimized?

Answer 9

1. on farm biosecurity
2. vaccination
3. waste treatment before release

Question 10

How is risk of O157:H7 from animal waste minimized?

Answer 10

1. on farm biosecurity
2. vaccination
3. waste treatment before release

Question 11

How is cryptosporidium spread?

Answer 11

1. water contaminated with feces
2. contact with infected persion
3. water contaminated with animal feces

Question 12

What is the primary means to remove cryptosporidium oocysts from water?

Answer 12

filters becuase resistant to chemical disinfection

Question 13

What is the minimal dose to get infected with cryptosporidium

Answer 13

10 oocysts

Question 14

What are some features of cryptosporidium oocysts?

Answer 14

immediately infective
appear at onset of symtoms
can be in stool for weeks without symptoms
can remain infective outside body for 2-6 months

Question 15

What are three sources of infection with cryptosporidium?

Answer 15

1. recreational water
2. contact with livestock
3. drinking water
4. person to person

Question 16

How are cryptosporidium parvum and homminis distinguished in the lab?

Answer 16

real time PCR

Question 17

What are factors that contribute to cryptosporidium outbreaks? REMEMBER

Answer 17

1. small oocysts
2. wide host range
3. close associations between human and animal health
4. large number of oocysts excreted
5. low infective dose
6. robust oocyts resistant to chlorine
7. infectious sporulated oocysts excreted

Question 18

why was there a cryptosporidium outbreak in Milwaukee?

Answer 18

storm washed fecal contamination, system failure allowed crypto to pass into water filters and proliferate in water supply

Question 19

Why did the outbreak in North Battleford occur?

Answer 19

1. the drinking water intake is below the sewage outfall
2. operations supervisor retired early
3. repair to the water treatment area
4. there was not coagulant sludge retained when it was restarted. There was not the proper material to seed and settle out material–solids contact unit

Question 20

What is a characteristic of waterborne outbreaks?

Answer 20

high proportion of the population is affected, illness is experienced in all age groups, affected persons have epidemiological link to on community or water source

Question 21

What constitutes a waterborne outbreak? remember?

Answer 21

1. 2 or more people with similar illness

2. epidemiological evidence that implicates water as porbable cause

Question 22

Large municiple outbreaks are due to one or more of?

Answer 22

1. inadequate disinfection
2. cross connections
3. inadequate control over treatment process
4. interruption in treatment
5. disruption in service
6. infiltration of polluted water

Question 23

What is information used in water outbreak investigation?

Answer 23

1. water plant process monitoring data

2. pu

Question 24

What is information used in water outbreak investigation?

Answer 24

1. water plant process monitoring data
2. public health results for clin lab, emergency room, physician visits for gastroenteritis
3. school, daycare absences
4. nursing home diarrheal rates
5. sale of anti-diarrheal drugs

Question 25

what is an indicator organism?

Answer 25

e. coli

Question 26

Why is e. coli an indicator organism?

Answer 26

1. universally present in large numbers in feces of humans and warm-blooded animals
2. readily detectable by simple methods
3. does not grow in natural waters
4. persistence in water and removal by treatment similar to waterborne pathogens
5. when resources are scarce it is recommended to test more drinking water more frequently with a simple test rather than less often by several tests
6. criterion: e. coli not detectable in 100mL sample

Question 27

Why is cryptosporidia and giardia not routinely tested in SK

Answer 27

analysis rates have low recovery

2. present methods do not ID viable oocysts

Question 28

how many times is water checked if there are 500 people?

Answer 28

2x/month

Question 29

How often is water tested for chemicals in a town of 5000?

Answer 29

once every 2 years

Question 30

Why is tap water better than bottled water?

Answer 30

it is not tested as frequently

Question 31

what can get rid of crypto and giardia in water?

Answer 31

UV light, ozone