Clinical Signs Acute signs can result within 1-12 hours following inhalation or cutaneous absorption and more rapidly following ingestion. The clinical signs of organophosphate poisoning occur as a result of excess acetylcholine at nerve endings, which mimics hyperactivity of the parasympathetic nervous system. Signs relative to the alimentary tract include excess salivation, lacrimation, abdominal pain, vomiting, intestinal hypermotility, and diarrhea. The muscarinic effects of acetylcholine cause bronchoconstriction and an increase in bronchial secretions. The nicotinic effects of acetylcholine consist of involuntary irregular, violent muscle contractions and weakness of voluntary muscles.
Death occurs as a result of respiratory failure.
Clinically affected animals may lose weight due to the inability to feed and drink because of muscular weakness. Non-fatal cases usually recover within 48 hours. Susceptibility to organophosphate toxicity varies greatly among individuals of any species and can be increased by frequent repeated mild exposure which results in greater susceptibility due to exhaustion of the body's store of cholinesterase. No definite postmortem changes are seen and when present, are usually secondary to the symptoms and include pulmonary edema, asphyxia, gastroenteritis, and rarely kidney and liver degeneration. As postmortem findings are usually not revealing, diagnosis is usually made by laboratory analysis.