[Viral infections].

Viruses cause disease after they break through the natural protective barriers of the body, evade immune control, and either kill cells of an important tissue or trigger a destructive immune and inflammatory response. The outcome of a viral infection is determined by the nature of the virushost interaction and the host's response to the infection. Viral infections can be lytic or persistent (latency, recurrence and / or transformation of the the cell). Immune response is the best treatment, but it often contributes to the pathogenesis of a viral infection. The laboratory methods accomplish the following results: description of virus-induced cytopathologic effects (CPEs) on cells, electron microscopic detection of viral particles, isolation and growth of the virus, detection of viral components (proteins and nucleic acids) and evaluation of the patient's immune response to the virus.