Intoxicação por organofosforados em bezerros no Uruguai

Acta Scientiae Veterinariae

Telefone: (51) 3308-6964
ISSN: 16799216
Editor Chefe: [email protected]
Início Publicação: 31/12/1969
Periodicidade: Trimestral
Área de Estudo: Medicina Veterinária

Intoxicação por organofosforados em bezerros no Uruguai

Ano: 2011 | Volume: 39 | Número: 3
Autores: André Gustavo Cabrera Dalto, Luiz Albornoz, Paula Cristina Sieczkowisky Gonzalez, Ana Paula Gobbi de Bitencourt, Danilo Carloto Gomes, Pedro Miguel Ocampos Pedroso, Paulo Mota Bandarra
Autor Correspondente: André Gustavo Cabrera Dalto | [email protected]

Palavras-chave: intoxicação, organofosforados, bezerras, uruguai

Resumos Cadastrados

Resumo Inglês:

Background: Organophosphate compounds are used worldwide in animal agriculture as pesticides, inseticides and herbicides.
The inappropriate use of these anticholinesterasic agents may cause poisoning, apart of great economic losses. Organophosphate
poisoning may affect all animal species. Organophosphate overdose induce increase in tissue acetylcholine content and,
therefore, enhanced parasympathetic and post-ganglionic sympathetic nerve activities. The toxic effects are shown as muscarinic,
nicotinic and central nervous system signs. The muscarinic signs are characterized by increased peristaltism, salivation,
lacrimation, nasal discharge, bronchial constrition, miosis and sudoresis, among others. The nicotinic signs are mainly locomotor
signs and include muscular tremors, weakness, and flaccid paralysis. The effects on the central nervous system include
inquietation, ataxia, convulsions, depression and coma. Minimal differences may be seen in the diseases caused by different
compounds; nevertheless, the route of administration may facilitate the exacerbation of some signs instead of others.
Case: This paper report an outbreak of organophosphate poisoning in calves. The disease occurred in a dairy farm located in
Florida, Uruguay and affected female Holstein 15-day-old calves. The main owner complaints were apathy, standing difficulty
and sialorrhea. Seven out of twenty calves presented neurological signs such as incoordination and sternal recumbency. The
clinical examination revealed prostration, lacrimation, tongue protusion, muscular weakness and miosis. At anamnesis, the
previous application, in the day before, of a pour-on inseticide was noticed. The composition of the commercial product was
ethion (15%), which is an insecticide organophosphate widely used as an antiparasitic drug. Affected animals were treated
with intravenous atropine sulfate 1% (0.50 mg/kg) and sodium chloride 0.9%. Atropine sulfate is a potent parasympatholytic
agent that inhibits the effects of acetylcholine at the postganglionic parasympathetic neuroeffector junctions. Ten minutes
after the treatment, most calves showed an improvement in health status. Only one calf needed two extra doses at 1-hour
intervals to recuperate. The presumptive diagnosis was based on the clinical findings and supported by depressed blood
cholinesterase level.
Discussion: The rapid therapeutic response of affected animals to specific treatment also supports the hypothesis. The outcome
of this outbreak relies in the aggressive approach of the team and adequate treatment choice. In spite of other differential
diagnosis possibilities such as poisoning by carbamate and pyrethroid, the clinical findings, laboratory result and therapeutic
response allowed us to attribute this outbreak to the misuse of organophosphate. The key to an excellent outcome, when
dealing with organophosphate poisoning, is immediate treatment.