Waterbourne Disease

Question 1

What are the major pathogens associated with waterborne illness?

Answer 1

• Cholera
• Bacillary dysentery
• Legionnaires’ disease
• Leptospirosis
• Enteric viruses

Question 2

Why is water purification important?

Answer 2

It is essential for human health and helps prevent waterborne diseases.

Question 3

What is the role of sanitary analysis of water?

Answer 3

To monitor water quality and detect potential pathogens.

Question 4

Define indicator organisms in the context of water quality.

Answer 4

Organisms that indicate fecal pollution and the potential presence of pathogens.

Question 5

What are the criteria for indicator organisms?

Answer 5

• Suitable for all types of water
• Present when enteric pathogens are present
• Survive longer than enteric pathogens
• Not reproduce in water
• Simple assay
• Harmless to humans
• Direct relationship to fecal pollution

Question 6

What is cholera caused by?

Answer 6

Vibrio cholerae

Question 7

What are the symptoms of cholera?

Answer 7

• Acute and intense diarrhea
• Severe dehydration
• Hypovolemia
• Possible death without treatment

Question 8

How does cholera toxin function?

Answer 8

Toxin composed of two subunits A & B
•Subunit A - toxin with enzyme activity
•Subunit B - binds to intestinal receptors

• Hypersecretion of water and chloride ions
• Inhibits sodium ion absorption

Question 9

What is the incubation period for cholera?

Answer 9

1-3 days

Question 10

What is the primary treatment for cholera?

Answer 10

• Rehydration therapy
• Antimicrobial therapy

Question 11

What is bacillary dysentery also known as?

Answer 11

Shigellosis

Question 12

What is a key characteristic of Shigella spp.?

Answer 12

Gram-negative, non-motile rods

Question 13

What are the four Fs associated with the transmission of bacillary dysentery?

Answer 13

• Food
• Fingers
• Faeces
• Flies

Question 14

What symptoms are associated with legionnaires’ disease?

Answer 14

Pneumonia

Question 15

What organism causes legionnaires’ disease?

Answer 15

Legionella pneumophila

Question 16

What are common sources of Legionella pneumophila?

Answer 16

• Hot tubs
• Water tanks
• Cooling towers
• Decorative fountains

Question 17

What are methods of preventing legionnaires’ disease?

Answer 17

• Regular disinfection
• Chemical level checks
• Daily flushing of fixtures
• Temperature control

Question 18

What causes leptospirosis?

Answer 18

Leptospira genus

Question 19

What are the symptoms of leptospirosis?

Answer 19

Flu-like symptoms

Question 20

What are the two main types of waterborne viral diseases?

Answer 20

• Hepatitis A and E
• Poliomyelitis

Question 21

What is the incubation period for hepatitis A and E?

Answer 21

2-6 weeks

Question 22

What is the primary method for detecting coliforms in water?

Answer 22

Multiple tube fermentation method

Question 23

In the multiple tube fermentation test, what does a positive result indicate?

Answer 23

Presence of coliform bacteria based on gas production in lactose broths

Question 24

What is the significance of the Salk and Sabin vaccines?

Answer 24

• Salk vaccine: inactivated poliovirus vaccine for injection
• Sabin vaccine: attenuated vaccine for oral administration

Question 25

What is the purpose of sanitary analysis of water?

Answer 25

To ensure water is safe for consumption and meets health standards

Sanitary analysis helps in identifying contamination and assessing water quality.

Question 26

What is the significance of coliform count in water classification?

Answer 26

It indicates the level of fecal contamination in water

Different classifications of water supply are based on coliform counts.

Question 27

What are the coliform count classifications for water supplies?

Answer 27

• Excellent: 0 coliforms/100ml
• Satisfactory: 1-3 coliforms in not more than 5% of samples
• Doubtful: 4-10 coliforms in not more than 5% of samples
• Unsatisfactory: >10 coliforms or 1 or more E. coli

These classifications help assess the potability of water.

Question 28

What is the Colilert® system used for?

Answer 28

Detecting bacteria in water using multiple tube fermentation method

It includes inhibitors to prevent unwanted organisms and two carbon sources.

Question 29

What are the two carbon sources used in the Colilert® system?

Answer 29

• ONPG (ortho-nitrophenolgalactopyranoside)
• MUG (4-methyl-umbelliferylglucuronide)

These substrates help in the detection of coliforms.

Question 30

What molecular technique can distinguish pathogens from commensals?

Answer 30

16S rRNA with gene-targeted primers

This technique allows for the identification of specific bacteria in samples.

Question 31

What is the detection limit for routine coliform detection in water?

Answer 31

1 cfu/100ml

This level of detection is crucial for ensuring water safety.

Question 32

What is flow cytometry used for in water analysis?

Answer 32

Detecting Cryptosporidium spp.

Flow cytometry is a rapid method for identifying pathogens in water.

Question 33

What are indicator organisms?

Answer 33

Microorganisms used to assess the microbiological quality of water

They serve as a measure of potential contamination.

Question 34

True or False: E. coli is always present in excellent water supply classifications.

Answer 34

False

Excellent water supply classifications have 0 E. coli count.

Question 35

Fill in the blank: The classification ‘Doubtful’ for water supplies is defined by a coliform count of _______.

Answer 35

4-10 in not more than 5% of samples

This classification indicates potential health risks.