Which one of these diseases is a water-washed disease?

Video Quiz 1

What does "HWTS" mean?

1. Household Water Treatment Systems

2. Household Water Treatment and

3. Sanitation

4. Household Water Treatment and Safe Storage

 

Which one of these diseases is a water-washed disease?

1. Trachoma

2. Malaria

3. Dengue fever

 

Which of these diseases causes the largest numbers of deaths each year?

1. Diarrheal diseases

2. Malaria

3. Lower respiratory infections (e.g., pneumonia)

4. Tuberculosis

 

How do you calculate “Years Lived with Disability” (YLD)?

1. Number of cases / Disability weight x Duration in years

2. Number of cases + Disability weight + Duration in years

3. Number of cases x Disability weight x Duration in years

4. Number of cases x Disability weight / Duration in years

 

Please check all the correct statements about E.coli

1. E.coli is always pathogenic.

2. E.coli is found in human and animal faeces.

3. Only pathogenic E.coli are considered to be good indicator bacteria

 

Please check all statements that are correct.

1. Cryptosporidium is one of the leading causes for diarrheal diseases among children.

2. Bacteria contain a nucleus.

3. Escherichia coli are normally not pathogenic.

4. Many viruses are host specific, causing diseases in humans or specific animals only.

 

Homework quiz 1

Question 1

According to the Bradley classification, there are four types of diseases transmitted by water: waterborne, water washed, water based and water related. Which one of these diseases is classified as water based, and why? Please select one answer.
Dracunculiasis, because the parasite that causes the disease lives part of its cycle in water.
Malaria, because the mosquitos need water to breed.
Malaria, because the mosquitos infect the water.
Dracunculiasis, because poor hygiene related to the lack of water favours its transmission.

 

Question 2

Different water-borne pathogens can cause different diseases. One of these diseases is cholera. This disease can spread quickly under poor sanitation and hygienic conditions, for instance, after a natural disaster or in refugee camps. It can cause death if not rapidly treated. This disease is…
... caused by a pathogen belonging to the class of bacteria. This pathogen is called vibrio cholerae..

... caused by a pathogen belonging to the class of viruses. This pathogen is called choleratus.
... caused by a pathogen belonging to the class of protozoa. This pathogen is called cryptocholera.
... caused by a pathogen belonging to the class of the helminths. This pathogen is called cholera worm.

 

Question 3

Escherichia coli. is considered to be a good indicator to identify faecal contamination in water. However, it is not an ideal indicator. Why is that? Please select one answer.
An ideal indicator should be easy to count. The techniques to count Escherichia coli are very complicated and expensive.
An ideal indicator should be persistent and unable to develop in the environment.
An ideal indicator should be easily eliminated by common water treatment methods.
An ideal indicator should be harmful to humans, to indicate if it can cause diseases.

 

Question 4

Among the treatment processes that we discussed are filtration and disinfection with heat, ultraviolet radiation and chlorine. Which ones are less effective if the water has a high level of turbidity, and what can you do to reduce turbidity? Please check all that are correct.

Disinfection with heat. You can use pre-filtration to reduce turbidity.

Ultraviolet radiation. You can use pre-filtration to reduce turbidity.

Disinfection with heat. You can chlorinate your water to reduce turbidity.
Chlorine. You can use pre-filtration to reduce turbidity.

 

Question 5

What are the disability adjusted life years (DALYs) for a person with a life expectancy of 84 who died at the age of 66, and who experienced blindness due to trachoma (disability weight = 0.58) for the last 10 years of her life? Hint: DALY = YLL + YLD. Please round your answer to the nearest whole number and write only the number into the answer field.
Examples of numbers rounded to nearest whole number: If the result of your calculation is 18.3, you would need to write 18. If the result of your calculation is 18.5 you would need to write 19.
Example of bad answer formats: 18 years (with words); 18.0 (with comas or points)
24

Question 6

The Sustainable Development Goals include Goal 6 to “ensure availability and sustainable management of water and sanitation for all.” Under this goal is Target 6.1 to “achieve, by 2030, universal and equitable access to safe and affordable drinking water for all.” From the answer choices below, choose the currently proposed indicator, definition, and data source for monitoring progress toward access to safely managed water.

Indicator: Percentage of population using household taps or protected wells
Definition: Population using a basic drinking water source located within 1 km and with only low levels of fecal and chemical contamination
Data source: Household surveys, GPS data collection

Indicator: Percentage of population using safely managed drinking water services
Definition: Population using a basic drinking water source located on premises and available when needed; free of fecal (and priority chemical) contamination
Data source: Household surveys, water quality testing, administrative data

Indicator: Percentage of population using an improved drinking water source
Definition: Population self-reporting use of a water source that is protected from contamination, especially fecal contamination, such as a piped network or borehole with handpump.
Data source: Household surveys

Indicator: Percentage of population using a protected water source
Definition: Population using a community tap or kiosk that is professionally managed
Data source: Household surveys, water quality testing

 

Video Quiz 2

Homework quiz 2

 

Question 1

Can an LRV (Log reduction value) be negative?
No
Yes

 

Question 2

1 gram of faeces from an infected person may contain 10,000,000 Cryptosporidium cysts. If all of that 1 gram of faeces were mixed in 1 liter of water, how many LRV (Log reduction values) would be needed to completely remove the cysts?
> 7 LRV
> 4 LRV
> 5 LRV
> 9 LRV

 

Question 3

Faecally derived pathogens are the principal concerns in setting health-based targets for microbial safety. It is not sufficient to measure the water quality only one time for verification. Why?
Microbial water quality often varies rapidly but not over a wide range.
Microbial water quality often varies rapidly and over a wide range.
Microbial water quality often varies slowly but over a wide range.

 

Question 4

Ceramic filters show very variable removal effectiveness depending on the class of pathogens. What LRV approximately can be achieved with ceramic filters regarding the removal of viruses?
0-2 LRV
2-5 LRV
3-4 LRV
6 LRV

 

Question 5

An example of a household membrane filter is Vestergaard-Frandsen’s LifeStraw. With a pore size of 20 nm, in which filtration category does it fall, and which classes of pathogens can it remove?

  It falls into the category of ultrafiltration. It can remove protozoa, bacteria and viruses.
It falls into the category of microfiltration. It can remove protozoa and bacteria.
It falls in the category of nanofiltration. It can remove protozoa, bacteria and viruses.
It falls into the category of microfiltration. It can remove protozoa, bacteria and viruses.

 

Question 6

Good operating procedures are important to maintain the performance level of a biosand filter. Which of the following are good operating procedures? Please check all that are correct..

A consistent water source should be used.
The flow rate shouldn’t be too fast nor too slow.

The biological layer should be changed every day.

The biological layer must be kept wet.

 

 

Video Quiz 3

Homework quiz 3

Question 1

Please check all the correct statements about the killing effect of heat on microorganisms.
Heat affects the proteins that make up cells of microorganisms.
Heat causes damage to the cells by denaturing the enzymes of microorganisms.
Heat can increase the pressure within a cell of microorganisms.
The killing effect of heat on microorganisms starts at boiling temperature.

 

Question 2

Which of the following are drawbacks of chlorination? Please check all that are correct.

People may find the taste and odour unpleasant.
Requires low turbidity water to be effective.
HWTS products require a functional supply chain.
According to the WHO, disinfection byproducts pose a relatively large health risk.
It is ineffective against at least some protozoa.

Question 3

 

Which membrane filtration technology requires the greatest amount of pressure to push water through the membrane pores? Please select the correct answer.
Ultra filtration

Nano filtration

Ceramic filtration

Reverse osmosis

Micro filtration

Question 4

Your colleague has two samples from different water sources. Sample A has been treated with a membrane filter; Sample B has been treated with SODIS. He informs you that he measured E. coli in both samples and the contamination level of Sample A has been reduced by 2 LRVs (Log Reduction Values), whereas the contamination level of Sample B has been reduced by 4 LRVs. He would like to know which water is safer to drink.
The provided information is not sufficient to know which water is safer to drink.
Water sample A (reduction of 2 LRVs) is safer to drink
Water sample B (reduction of 4 LRVs) is safer to drink.

 

Video Quiz 4

Video Quiz 5

Final quiz

Question 1

Which of the following treatment processes is LEAST prone to re-contamination following treatment? Please choose the correct answer.
Chlorine disinfection

Boiling

Ultraviolet treatment

Filtration

Question 2

How many DALYs are lost by a person who has a life expectancy of 74, contracts HIV/AIDS at the age of 40 and lives until the age of 60? This person receives antiretroviral medication two years after she/he contracts HIV/AIDS until she/he dies. [The weighting for HIV/AIDS without antiretroviral medication is 0.5. The weighting for HIV/AIDS with antiretroviral medication is 0.167.] Please enter only the number and rounded to a complete number (no text, no commas, no spaces, no decimal points).
Example for correct answer: 23
Examples for wrong answers: The answer is 23. (Do not include text in the answer.) / 23.1 (Do not include decimals. Round to the nearest integer.)

Question 3

What is the most commonly used faecal indicator bacteria?
Escherichia coli

Rotavirus

Faecal streptococci

Shigella

Question 4

The Global Enteric Multicenter Study (GEMS) was a large study about childhood diarrheal diseases in developing country settings. One of the key findings was that just four pathogens were responsible for the majority of moderate-to-severe diarrhea cases. What are the names of these four pathogens? Please check the four correct answers.
Shigella

Enterobacter

Salmonella

Guinea worm

Cryptosporidium

Rotavirus

Enterotoxigenic E. coli (ETEC)

Poliovirus

Question 5

The Water Safety Framework is made up of 5 distinct components: health based targets, system assessment, operational monitoring, management and communication, and verification. Which three components from this list are included in a Water Safety Plan? Please select the correct answer.
"System assessment", "Operational monitoring", "Management and communication"
"Health based targets", "System assessment", "Operational monitoring"
"Health based targets", "Verification", "System assessment"
"Operational monitoring", "Management and communication", "Verification"

Question 6

A sample of human feces contains 10’000’000 viruses per gram of feces. One gram of this sample is mixed into 1 litre of water and is then exposed to UV-C radiation at a dose of 400 J/m2, reducing the concentration to 1’000 viruses/L. What is the log removal value (LRV) of this UV treatment method? Please select the correct answer.
LRV = 8

LRV = 4

LRV = 2 

LRV = 6

Question 7

What is the most commonly practiced household water treatment practice in the world? Please select the correct answer.
Membrane filtration

UV treatment

Boiling

Chlorine disinfection

Question 8

Solar disinfection (SODIS) relies on ultraviolet light. Which UV-light cannot be used to apply SODIS?

  UV-C

UV-B

UV-A

Question 9

CLARO, WaterGuard, and Sur’Eau are examples of …? Please select the correct answer.
Safe storage devices

Chlorine disinfection products

Water Safety Plans

Behavior change communication strategies

Question 10

The WHO has established a series of health-based microbiological performance targets for household water treatment methods, ranging from an interim target to highly protective. For which pathogen(s) did WHO establish these targets ?
For all 24 pathogens classified in the WHO high-risk category for global burden of disease (e.g., E.coli, Vibrio Cholerae, Ebolavirus, Rotavirus, Giardia, Cryptosporidium)
For E. coli

For Campylobacter jejuni, Rotavirus and Cryptosporidium

Question 11

A household water treatment technology has the following removal efficiencies: Bacteria: 5 LRV; Viruses: 1 LRV; Protozoa: 2 LRV. What class of protection would this be called, using the WHO evaluation criteria?
Limited protection

Highly Protective

Protective

Question 12

Which of the following are study designs that can be used to evaluate the health impacts of household water treatment interventions? Select all that are appropriate.
Case control studies

Cohort studies

Ecological studies

Randomized control trials

 

 

Video Quiz 1

What does "HWTS" mean?

1. Household Water Treatment Systems

2. Household Water Treatment and

3. Sanitation

4. Household Water Treatment and Safe Storage

 

Which one of these diseases is a water-washed disease?

1. Trachoma

2. Malaria

3. Dengue fever

 

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