An outbreak of systemic intoxication with irritant contact dermatitis due cypermethrin in dairy cows: case report / Surto de intoxicação sistêmica com dermatite de contato irritante devido à cipermetrina em vacas leiteiras: relato de caso

Pyrethroids are ectoparasiticides safe for mammals and widely used in farm animals. An outbreak of systemic intoxication with irritant contact dermatitis resulting from the use of cypermethrin pour on in dairy cows is reported in the state of Pernambuco. Eight adult animals were affected, three died on the property and five were referred to the Clínica de Bovinos, Universidade Federal Rural de Pernambuco, Campus Garanhuns. These received 100 mL of pour on Cypermethrin (Ectonil ®, Cipermetrina, Labgard, Brasil). Apathy, hyperexcitability, muscle tremors, sialorrhea, bradycardia and crusted lesions were observed on the dorsum of the neck, scapula, ears and ulcerations in the oral and vaginal mucosa. There was hyperfibrinogenemia and leukocytosis due to neutrophilia with a regenerative left shift. Histopathology showed areas of erosion and ulceration of the epidermis and perivascular lymphohistiocytic and neutrophilic infiltrate in the superficial dermis. Supportive treatment was done with improvement of systemic signs and skin lesions, however, in one animal (with 19 days hospitalized), there was no complete regression of neurological alterations of bradycardia and muscle tremors, even so, it was possible to return to productive activity. High doses of pour on cypermethrin may cause systemic intoxication in cattle and result in bradycardia, hyperexcitability, muscle tremors and sialorrhea with irritant contact dermatitis, and death in severe cases.

Os piretroides são ectoparasiticidas com grande segurança para mamíferos, utilizados amplamente em animais de produção. Relata-se um surto de intoxicação sistêmica com dermatite irritante por contato, resultante do uso de Cipermetrina Pour-On em bovinos, no estado de Pernambuco. Oito animais adultos foram acometidos: três deles morreram na propriedade e cinco foram recebidos na Clínica de Bovinos da Universidade Federal Rural de Pernambuco, Campus Garanhuns. Todos haviam recebido 100mL de Cipermetrina Pour-On (Ectonil®, Cipermetrina, Labgard, Brasil). Observou-se apatia, hiperexcitabilidade, tremores musculares, sialorreia, bradicardia e lesões crostosas no dorso da região de pescoço, na escápula, mas orelhas, bem como ulcerações em mucosa oral e vaginal. No hemograma, verificou-se hiperfibrinogenemia e leucocitose por neutrofilia com desvio à esquerda regenerativo. Na histopatologia, foram constatadas áreas de erosão e ulceração da epiderme e infiltrado linfo-histiocitário e neutrofílico perivascular na derme superficial. O tratamento de suporte gerou melhora dos sinais sistêmicos e das lesões cutâneas, porém, em um dos animais (que esteve internado por 19 dias), não houve regressão completa das alterações neurológicas de bradicardia e de tremores musculares; mesmo assim, foi possível o retorno à atividade produtiva. Doses elevadas de Cipermetrina Pour-On podem causar intoxicação sistêmica em bovinos e resultarem em bradicardia, hiperexcitabilidade, tremores musculares e sialorreia com dermatite irritante por contato, bem como morte em casos severos.

Efeito colateral da anestesia local subcutânea com vasoconstritores em bovinos

In order to study the effects of different local anaesthetics with and without vasoconstritor (epinefrine), 20 adult crossbred cows were used. The following treatments were carried out:T1 - control (bidistilled water); T2 - chloridrate of lidocaine (20 mg/ml) with epinephrine (0.005 mg/ml); T3 - chloridrate of lidocaine (20 mg/ml) with epinephrine (0.02 mg/ml); T4 - chloridrate of lidocaine (20 mg/ml) with epinephrine (0.05 mg/ml); T5 - chloridrate of lidocaine(20 mg/ml); T6 - chloridrate of procaine (22 mg/ml) with epinefrine (0.02 mg/ml); T7 - chloridrate of procaine (22 mg/ml). The different solutions were injected, at the same time, into the subcutaneous space of the medial chest line, 10cm apart, of all cows. Observation at the infiltration sites was made 72 hours later, for the presence or not of tissue reaction, as well as lesion degrees. No differences were found among T1, T5, T6, and T7 , which did not cause tissue reaction. On the other hand, lower lesion tissue degrees were found in cows treated with T2 as compared to T3 and T4. It can be concluded that the use of both local anaesthetics alone or chloridrate of procaine with epinefrine are harmless to the skin while chloridrate of lidocaine associated with any concentration of vasoconstritor may give rise to tissue lesions in cattle.