Water & Disease Flashcards
Describe eco-sanitation (or dry sanitation) and pros/cons of it.
Dehydrating and composting of waste typically using special toilets to separate liquid and solid wastes. It uses less water and recycles solid waste for use in agriculture. Composting, however, may not always eliminate pathogens even though elevated temperatures are maintained during composting, it is sometimes logistically difficult and sometimes not accepted culturally.
Based upon Dr. Leon’s lecture, which is the most important change that will improve WASH in developing areas:
Behavioral change is the most important but is more powerful with coupled with infrastructure development.
Diarrheal disease may develop from a child defecating near or in an open stream which people use for drinking water. Name a primary barrier(s) and a secondary barrier(s) for this disease.
Primary – eliminate defecation in streams by behavioral modification
Secondary – sanitize water prior to consumption; handwashing
Define and differentiate water quantity, water access, and water quality.
Water quantity is the amount of water available to an individual/community
Water access is the communty or individual’s ability to use this water
Water quality is a measure of the potability of the water for consumption. It can be a subjective or objective measure (e.g., water from the Ganges river may be considered spiritually pure but may be biologically impure).
What is point of source vs. point of use contamination?
Water that is contaminated where you obtain it (eg. a river with fecal matter) is point of source contaminition. Point of use contamination occurs when you sample the water for use (e.g., dip hands with fecal matter into water to scoop up a drink of water).
Define and differentiate sanitation and hygiene.
Sanitation is the treatment of waste by hygienic disposal or recycling and this is typically community-based. Hygiene is the practice of keeping oneself and surrounding area clean which is typically practiced on an individual level.
Controlling 1 disease may require multiple hygienic behaviors but 1 hygienic behavior may control multiple diseases (not a question but important concept).What steps are involved involved water sanitation intervention research:
Determine the baseline; identify aspects that are most hazardous
Develop intervention (behavioral or infrastructure or both)
Assess the outcome of the intervention. Are more interventions required? Evaluate.
Make intervention sustainable.
Who first isolated “Vibrio comma” in pure culture that was later found to be the etiologic agent of cholera (Vibrio cholerae)?
Robert Koch
When was the vibrio toxin isolated?
1959
What is cholera’s primary action on your body and how is it treated?
It removes water from your body causing severe dehydration through the elimination of watery stools. Oral rehydration salts, IVs and other rehydration steps can be used to treat it, if available.
Is cholera viable when not in a culturable state?
Yes, it has a unique dormant stage.
Explain how near shore coastal cholera can occur.
phytoplankton carry Vibrio cholerae which adheres to the chitin in the exoskeleton of the zooplankton that encounter it. Shellfist then acquire it and humans in near shore coastal regions ingesting shellfish can contract it and they circulate it among their communities sometimes transmitting the disease inland.
What was the simple device that Rita Colwell came up with for cleaning water that may contain Vibrio cholerae and why would it work?
She used old Sari clothes with frayed fibers that would filter out a significant portion but not all of the cholera-causing organisms. Because the infectious dose is so high (103-108), it kept the water concentration below this dose.
How many cholera bacterium do you need exposure to in order to become ill? Is it a lot or not?
10^3 to 10^8 that is a LOT you can be exposed to
What is an affordable method to reduce exposure to cholera?
use a sarrie to reduce quantity of plankton in the water, reducing then the cholera
