Organophosphorus pesticides are the most widely used, the largest amount of a class of highly effective insecticides, can kill a variety of crop pests, in the dog in the prevention and control of ectoparasitic diseases and environmental pest control is also more often used. Often due to poor storage, improper use, environmental pollution, causing poisoning. The condition is critical, such as rescue is not timely, mostly to death for the return.
Organophosphorus pesticides include: dichlorvos, chlormequat chloride, trichlorfon, endosulfan, parathion, methamidophos and malathion. Trichlorfon is mainly used for the prevention and control of external and internal parasitic diseases in dogs.
(i) Main causes
1, drive to kill surface parasites, such as killing helminth mites, itch mites, ticks, with too large a time, concentration is too high, the use of drugs too large an area, the use of drugs for too long.
2、Expel body parasites, such as nematode parasites, sometimes also choose trichlorfon orally, can be too large and cause poisoning.
3, accidentally eat, drink by organophosphorus contaminated food, water, inhalation of contaminated air and so on.
Clinical manifestations
Canine organophosphorus poisoning due to the different degrees of severity of the performance is different.
1, mild poisoning: depression, appetite, salivation, nausea and vomiting, diarrhea, mild restlessness.
2, moderate poisoning: abnormal excitement, loss of appetite or waste, vomiting, salivation, serious, bowed back, pain and restlessness, pupil narrowing, vision loss, shortness of breath, rapid heartbeat, body temperature, intestinal sounds, abdominal excretion serious, frequent urination or drenching.
3、Serious poisoning: high mental agitation, violent convulsions of the whole body, profuse salivation and tearing, abdominal pain and diarrhea, difficulty in urging, rapid heartbeat, cardiac rhythm disorders, urinary and fecal incontinence, pupil narrowing, generalized fever, collapse, unconsciousness, epileptic seizures, and finally respiratory paralysis leading to respiratory arrest.
Diagnostic points
1. Understand the history of touch and misuse.
2. Diagnose according to clinical features.
3、The exhaled air and vomit of sick dogs may have special garlic odor.
4、Determine the blood cholinesterase activity: take a small piece of filter paper, successively immerse it in 1% choline chloride and bromine musk xylenol blue solution, add a drop of blood to be examined, clamp it between two slides, place it in 37 degree Celsius for 20 minutes in the incubator, take it out and observe. The red color is normal, the purple color is mild inhibition, the dark purple color indicates moderate inhibition, and the blue-black color is severe inhibition.
5. Changes in autopsy: stomach contents with garlic odor. Stasis, swelling and hemorrhage in the digestive tract, epithelial detachment or necrosis, liver and spleen enlargement, kidney enlargement, lung congestion, hemorrhage and edema.
aid measures
1. For severely poisoned dogs, apply special antidotes:
(1) Apply acetylcholine antagonist atropine sulfate immediately. Early, adequate, quick and repeated administration should be done until the condition is relieved or “atropine-ized”, and then switch to maintenance dose. The general therapeutic dose is 0.1mg/kg body weight intravenously, and the same dose should be injected subcutaneously once every 0.05-1 hour. After the pupils are dilated to normal, salivation stops, breathing is stable and awake, gradually reduce the dosage and the number of times of dosage, until the condition is completely stabilized.
(2) Application of cholinesterase reenergizing agents
The most commonly used ones are chlorophos and diphosphidine. Add 15% dextrose saline 500 ml into 15-30mg/kg body weight and inject slowly intravenously. Repeat once every 2-3 hours if necessary, with the dose reduced by half. If atropine is applied at the same time, the efficacy is better, but the dosage of atropine should be relatively reduced.
If poisoned by oral intake, immediately wash the stomach. For trichlorfon poisoning, avoid using alkaline solution, and wash the stomach with water. Other organophosphorus poisoning can be used 2% sodium bicarbonate antidote gastric lavage, gastric lavage is completed into the sodium bicarbonate powder or charcoal about 100 grams each. When gastric lavage, it should also be noted that avoid using hot water, generally do not use potassium permanganate solution.
through the skin detoxification poisoning, cold soapy water or 3% sodium bicarbonate water can be used to carefully wash the ears, and then wash with warm water. But such as trichlorfon poisoning, prohibit alkaline water solution, only available water rinse.
Symptomatic treatment
(1) Transfuse sugar and fluid as early as possible to increase the detoxification function of liver and detoxification function of kidney.
(2) When respiration is extremely difficult, oxygen and respiratory stimulant can be injected. Such as 25% Nicosamide or camphor. For severe hypoxia and respiratory insufficiency, tracheal intubation and artificial respiration are required.
(3) manic or convulsive animals, available sedative, antispasmodic drugs. Such as chlorpromazine, phenobarbital sodium.
4) Correct water and electrolyte metabolic disorders and acid-base balance imbalance.
rescue precautions
(1) For mild poisoning, atropine or dephosphorylation can be used alone, and reduce the dose and number of times the drug is used.
(2) For moderate to severe poisoning, the combination of atropine and antiphosphidine is preferable. The second dosage should be reduced by half.
(3) The application of cholinesterase resuscitator should not be paired with alkaline drugs. And the effect is poor in chronic organophosphorus poisoning and dichlorvos poisoning, atropine should be emphasized to detoxify.
(4) Organophosphorus poisoning, avoid using oil laxative.
