Febre aftosa: estudo da reação vacinal em animais primovacinados.

Abstract

Vaccination, combined with other sanitary measures, has allowed significant advances in the fight against foot-and-mouth disease in Brazil. The major anti-foot-and-mouth disease vaccines currently available on the world market have oily and adjuvant vehicles capable of providing slow release and longer and earlier protection. In contrast, its use may determine the appearance of tissue damage and significant inflammatory reactions. Considering the current context of control and eradication of foot-and-mouth disease in Brazil, in which systematic vaccination is still the main tool, the present study was developed with the objective of observing the occurrence of adverse reactions to the vaccine in never vaccinated animals and the influence of the adoption of the technical recommendations established by the health authorities in their manifestation. Twenty-nine healthy cattle were selected, 11 males and 18 females, all mestizos of breeds specializing in milk production, aged less than or equal to six months of age, never vaccinated against foot-and-mouth disease, belonging to the Center's bovine cattle sector of Agricultural Sciences of the Federal University of Paraíba. In accordance with the technical guidelines for vaccination, five mL of the vaccine was applied to the right side of the neck, specifically in the cervical portion of the trapezius muscle. Sterilized stainless steel hypodermic needles were used for this purpose. On the left side of the neck, with the aid of disposable syringes and hypodermic needles, an equivalent volume of physiological solution, used as a placebo, was applied according to the same criteria adopted in the contralateral region. At day zero and in the intervals of 7, 14, 21 and 28 days after the procedure, body temperature and skin thickness were evaluated in both application regions. There was a significant increase in cutaneous thickness and formation of solid, circumscribed and salient lesions in the region of inoculation of the vaccine, especially between 14 and 21 days after vaccination, with a marked regression in 28 days, with no changes in thickness in the opposite region. Variables such as temperature, sex, race and age did not present a positive correlation with the evolution of the lesions. In view of the results achieved, it was considered that, from the adoption of technical recommendations for the execution of vaccination, the occurrence of post-vaccinal hypersensitivity reactions are acceptable, as long as they are localized and transient.