Organophosphate Toxicity

Recently we had a couple cases at the clinic involving puppies exhibiting signs of sickness and weakness.  The pups had been vomiting, having diarrhea, and showing signs of weakness and lack of coordination.  At first the signs and symptoms seemed to point towards Parvovirus, a common but very serious disease often seen in puppies.  After checking the puppies' records, it was brought to our attention that both were up to date on Parvovirus vaccinations.  The pups were tested anyway to be safe, and sure enough both were negative for Parvo.  The owners of one puppy said they had applied a topical flea medication and saw symptoms shortly after.  The owners of the second puppy had applied Seven dust in order to rid of a flea infestation.  The veterinarian dealing with the cases immediately knew what was the cause of the problem.  He diagnosed the pups with organophosphate toxicity or in other words, insecticide poisoning.  Organophosphate poisoning results from overexposure to organophosphates by inhalation, ingestion, or dermal contact.  These compounds are a diverse group of chemicals used in both domestic and industrial settings.  Examples include insecticides, herbicides, nerve gases, ophthalmic agents, and anthelmintics.  The most common form of organophosphates that pets are exposed to are found in lawn and garden treatments and flea and tick treatments.  Organophosphates work by inhibiting acetylcholinesterase, an enzyme critical for nerve function.  Inhibition of acetylcholinesterase causes an accumulation of acetylcholine, a neurotransmitter, in the body, which results in nerve and muscle overstimulation.  Some noticeable symptoms include fever, vomiting, diarrhea, anorexia, depression, seizures, muscle tremors, hypersalivation, constricted pupils, increased heart rate, lack of coordination, and respiratory failure.  Once diagnosed with organophosphate poisoning, the animal needs to be stabilized, decontaminated, and treated.  Treatment includes the following, bathing the animal to remove remaining chemical residue, inducing vomiting to flush out the stomach if poison was ingested, administering IV fluids, and administering drugs such as atropine to counteract the effect that organophosphates have on the nervous system.  Despite the large variety and widespread use of organophosphates, poisoning can be prevented.  Insecticides and other organophosphates should be researched and labels should be followed correctly before using in the home, on the lawn, in the garden, or on pets.