Diseases Caused by Pesticides

1. Introduction and Definitions

Pesticides are chemical substances used to control pests, including insects, weeds, fungi, and rodents. They are widely used in agriculture, public health, and industry to protect crops, control disease vectors, and manage invasive species. However, exposure to pesticides can lead to significant health problems, including acute and chronic diseases. This article provides comprehensive information on diseases caused by pesticides, targeting occupational health nurses and doctors.

2. Agent Causes the Disease

Pesticides encompass a wide range of chemical classes, each with distinct mechanisms of action and toxicological profiles. Common types of pesticides include:

  • Insecticides: Chemicals used to kill or repel insects (e.g., organophosphates, carbamates, pyrethroids).
  • Herbicides: Chemicals used to kill or inhibit the growth of unwanted plants (e.g., glyphosate, atrazine).
  • Fungicides: Chemicals used to prevent or eliminate fungal infections (e.g., chlorothalonil, mancozeb).
  • Rodenticides: Chemicals used to kill rodents (e.g., anticoagulants, bromethalin).

Exposure to these agents can occur through inhalation, dermal contact, or ingestion, leading to a range of toxic effects depending on the type and level of exposure.

3. Workers at Risk of This Disease

Several occupations and tasks put workers at higher risk of exposure to pesticides, including:

  • Agricultural Workers: Applying pesticides in fields, greenhouses, and orchards.
  • Pesticide Applicators: Using pesticides in residential, commercial, and industrial settings.
  • Forestry Workers: Using pesticides for forest pest management.
  • Public Health Workers: Applying pesticides for vector control (e.g., mosquitoes).
  • Manufacturing Workers: Involved in the production and formulation of pesticides.
  • Waste Disposal Workers: Handling pesticide-contaminated waste.

4. Symptoms

Symptoms of diseases caused by pesticide exposure can vary depending on the type of pesticide, level, and duration of exposure:

  • Acute Exposure: Symptoms may include headache, dizziness, nausea, vomiting, abdominal pain, diarrhea, sweating, salivation, muscle twitching, difficulty breathing, and convulsions. Severe cases can lead to respiratory failure, coma, and death.
  • Chronic Exposure: Long-term exposure can result in chronic health issues such as cancer, neurological disorders (e.g., Parkinson's disease), reproductive and developmental problems, endocrine disruption, and chronic respiratory conditions.

5. Diagnosis

Diagnosing diseases caused by pesticide exposure involves a combination of clinical evaluation, occupational exposure assessment, and specific tests:

  • Medical History and Physical Examination: Detailed assessment of the patient's work history and symptoms.
  • Blood and Urine Tests: Measuring levels of pesticide metabolites and biomarkers of exposure (e.g., cholinesterase activity for organophosphates and carbamates).
  • Pulmonary Function Tests: To assess lung function and detect any obstructive or restrictive patterns.
  • Neurological Evaluation: Including tests for cognitive and motor function if neurological symptoms are present.
  • Imaging Studies: X-rays or CT scans to detect organ damage, if necessary.

6. Treatment

Treatment for diseases caused by pesticides focuses on managing symptoms and preventing further exposure:

  • Remove from Exposure: Immediate removal from the source of pesticide exposure is crucial.
  • Decontamination: Removing contaminated clothing and thoroughly washing the skin to reduce dermal exposure.
  • Symptomatic Treatment: Providing medications to manage symptoms such as respiratory distress, seizures, and gastrointestinal distress. This may include bronchodilators, anticonvulsants, and antiemetics.
  • Specific Antidotes: Administering antidotes for certain types of pesticide poisoning (e.g., atropine and pralidoxime for organophosphate poisoning).
  • Supportive Care: Including hydration, nutritional support, and monitoring of vital signs and organ function.
  • Long-term Monitoring: Regular follow-up to monitor for chronic health effects and overall health status.

7. Prevention

Preventing diseases caused by pesticides involves implementing strict control measures in the workplace:

  • Engineering Controls: Using local exhaust ventilation, enclosed processes, and proper maintenance of equipment to reduce airborne exposure to pesticides.
  • Work Practices: Implementing safe work practices such as proper handling, storage, and disposal of pesticides, and avoiding eating, drinking, or smoking in areas where pesticides are used.
  • Personal Protective Equipment (PPE): Providing and ensuring the use of appropriate respirators, protective clothing, gloves, and eye protection.
  • Health Surveillance: Regular health screenings, including blood tests, neurological assessments, and pulmonary function tests for workers exposed to pesticides.
  • Education and Training: Informing workers about the hazards of pesticides and safe work practices to minimize exposure.

Workplace Exposure Limits:

  1. Organophosphates and Carbamates:

    • These compounds are potent cholinesterase inhibitors and can cause severe cholinergic toxicity.
    • OSHA PEL (Permissible Exposure Limit): Varies depending on the specific compound. For example, chlorpyrifos (an organophosphate) is found in some household insect sprays and has specific limits.
    • NIOSH REL (Recommended Exposure Limit): Notable examples include neostigmine and pyridostigmine (used for neuromuscular blockade reversal) and echothiophate (used for glaucoma and myasthenia gravis treatment).
  2. Glyphosate:

    • Glyphosate is a widely used herbicide.
    • OSHA PEL: Not specifically listed in the OSHA Z-1 Table.
    • NIOSH REL: Not specifically listed in the NIOSH Pocket Guide.
  3. Atrazine:

    • Atrazine is another herbicide.
    • OSHA PEL: Not specifically listed in the OSHA Z-1 Table.
    • NIOSH REL: Not specifically listed in the NIOSH Pocket Guide.