Veterinary Diagnostic using Transmission Electron Microscopy

Transmission electron microscopy has been an excellent tool, essential for the diagnosis of bacterial and viral animal diseases. Four basic techniques have been widely used: negative staining (rapid preparation), immunoelectron microscopy, immunolabeling with colloidal gold particles and resin embedding. The negative staining technique (rapid preparation) is the most applied, due to its speed, simplicity and specificity and can be used in various clinical specimens – such as feces, semen, urine, serum, organ fragments, crusts, body fluids, cell culture suspension, oral, ocular and fecal swabs, among others –, in which the agents can be directly viewed in large numbers in the samples. The immunoelectron microscopy technique using a specific primary antibody promotes the clumping of particles, also allowing the serotyping of the agents. In the immunolabeling with colloidal gold technique antigen-antibody reaction is enhanced by marking the antigen colloidal gold particles associated with protein A. The method of resin embedding, followed by ultrathin sections of cells or infected tissues can monitor the different stages of maturation viruses or bacteria and their behavior inside of host cells by determining not only the infection, but also the course of the disease in farms. The techniques can be applied to all animal species, either large or small, including aquatic and wild animals. Its implementation allows rapid diagnosis, providing subsidies for the immediate institution of prophylactic measures, and control and prevention of bacterial and viral animal diseases.