Lecture 28: Guest Lecture "the Wells and Enteric disease Transmission Trial (WET Trial)

Question 1

What is the background on the study?

Answer 1

-Groundwater is a significant sources of pathogens
-Sub-surface pathogen occurrence, distribution and movement poorly understood
-Evidence suggests that contaminated ground water is a significant source of gastrointestinal infections in both developed and developing regions
-Septic systems and agricultural activities can be potential sources for these pathogens

Question 2

What is the outcome in this study and what does it mean?

Answer 2

Acute Gastrointestinal Illness (AGI)
-3 or more loose stools in 24 hours or any vomiting excluding those with chronic conditions or current symptoms of coughing, sneezing, sore throat or runny nose

Question 3

How are wells contaminated?

Answer 3

-Surface contamination
- Septic systems
-Livestock waste storage pit
-Fertilization/ irrigation

Question 4

What kind of pathogens are in ground water?

Answer 4

-Viruses
-Bacteria
-Protozoa

Question 5

Why are outbreaks only the tip of the iceberg?

Answer 5

-Not all illnesses are linked to outbreaks (which have better surveillance)
-Endemic/sporadic disease are isolated cases that go under-reported and under-diagnosed

Question 6

How can we measure the sporadic/endemic cases of illness?

Answer 6

1. Epidemiological studies
   -Randomized control trial (RCT) best kinda
   -Community intervention trials (intervention at community level)
   -Case control studies (trace back to exposure to untreated well water)
   -Ecological studies (not as evidence strong)
2. Quantitative microbial Risk Assessment (QMRA) more of a mathematical approach
   -Determines the likely hood and extent of human health effects following an exposure to microbial pathogens
   -Less money and time consuming than epi studies

Question 7

What is the wells and enteric disease transmission (WET) trial?

Answer 7

-First randomized controlled trial of its kinda globally
-First RCT to determine if well water treated by UV can decrease AGI in children
-Done in Pennsylvania bc has the second highest number of private wells in the country

Question 8

What were the eligibility requirements for each household?

Answer 8

-Reliance on private well
-No water treatment (bc if have existing can’t be apart so not doing anything worse to houses with treatment already just making better for those who have nothing)
-Have to reside in Southeastern PA
-Have to have a child < 5 years old when they finish so just under 4 when start
-Drink 1+ of well waterier day
-Have no existing health conditions

Question 9

What happened in the study in general?

Answer 9

-908 participants
-1/2 with treatment UV device other 1/2 (control) without device
-Monitor both groups by following for1 year and weekly text messages and if have symptoms fill out illness questionnaire

Question 10

What was the additional data?

Answer 10

-BASeline questionnaires midpoint questionnaires and exit questionnaires
-Installer questionnaires (installer makes sure no other filter device present)
-Weather data

Question 11

What are the sub-cohort samples?

Answer 11

-Paired water and stool samples are collected in the absence and presence of symptoms
-Saliva samples are collected monthly

Question 12

What did participants need to do?

Answer 12

-Allow us to install UV device
-Complete baseline. midpoint, and end point questionnaire
-Respond to weekly yes or no text message for 52 weeks
-Respond to illness questionnaire when child is ill
-Submit stool/saliva samples (sub-set)
-Allow us to collect untreated water samples form outside their home or in basement (Sub-set)

Question 13

What are the WET trial strengths?

Answer 13

-Triple blinded
-Whole home device vs point of use (ie just on kitchen sink)
-Large sample size
-Innovative text message/digital-based data collection (>98% response rate, reduced recall bias)