The Use of Self-reported Symptoms as a Proxy for Acute Organophosphate Poisoning Among Nepali Farmers

Study Overview
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Brief Summary
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The purpose of this study is to evaluate self-reported symptoms as a proxy for acute organophosphate poisoning by examining self-reported acute organophosphate poisoning symptoms and PchE activity in response to occupational acute organophosphate exposure among farmers in Nepal.

Official Title
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The Use of Self-reported Symptoms as a Proxy for Acute Organophosphate Poisoning Among Nepali Farmers: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

Conditions
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Organophosphate Poisoning

Intervention / Treatment
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* Other: Organophosphate
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: male minimum age 18 years hand pressured backpack sprayer usage used to spray with moderately to extremely hazardous pesticides according to the World Health Organization's (WHO) Pesticide Hazard Classification Exclusion Criteria: usual personal protective equipment use (respirator/mask with particulate filter, face shield, googles, gloves, boots, plastic poncho) unwilling to stay pesticide-free seven days prior to each of the two spray sessions medical conditions interfering with PchE activity (liver disease, acute infection, chronic malnutrition, heart attack, cancer, obstructive jaundice, inflammation caused by various diseases, or use of pyridostigmine drugs)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Group A<br>Initial spray session: organophosphate. Crossover spray session: placebo | Other: Organophosphate<br>* Chlorpyrifos 50% plus cypermethrin 5%, WHO Class II: Moderately hazardous<br>Other: Placebo<br>* Multineem, WHO Class U: Unlikely to present acute hazard in normal use<br>* Other names: Biopesticide;|
| Other: Group B<br>Initial spray session: placebo. Crossover spray session: organophosphate | Other: Organophosphate<br>* Chlorpyrifos 50% plus cypermethrin 5%, WHO Class II: Moderately hazardous<br>Other: Placebo<br>* Multineem, WHO Class U: Unlikely to present acute hazard in normal use<br>* Other names: Biopesticide;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in self-reported acute organophosphate poisoning symptoms from baseline to follow up | Obtained using a structured questionnaire interview. The definition of symptoms was based on WHO's standardized list of clinical presentations of acute organophosphate poisoning. | Obtained just before (baseline) and 30 minutes after (baseline) each spray session | 
| Change in Plasma Cholinesterase (PchE) activity from baseline to follow up | PchE activity was measured with a blood test using a Test-mate Che Cholinesterase System (Model 400) with a PchE Plasma Cholinesterase Assay Kit (Model 470). | Obtained just before (baseline) and 30 minutes after (baseline) each spray session |