The causative agent can be identified by conventional serological samples and culturing in 30-70% of cases of serous meningitis. Cerebrospinal fluid studies using PCR indicate that at least two thirds of serous meningitis with negative results are caused by enterovirus cultivation - thus, they are the major viral pathogens of meningitis.
Also pathogens of viral meningitis are ECHO viruses, coxsackieviruses types A and B, mumps virus, Warr Epstata-virus, Togaviridae, bunyaviruses, arenaviruses, HSV type 2, cytomegalovirus and adenovirus.
As a rule, the acute onset of the disease, the body temperature rises to febrile digits. Develops headache, nausea, repeated vomiting. Severe weakness is accompanied by sleepiness, sometimes with a stun. In more severe cases, there is confusion up to the loss. Can be presented with myalgia that is a pain in the muscles of the body. Often the disease is accompanied by dyspeptic disorders with type of gastroenteritis by abdominal cramping, loose stools, appetite absent. The skin of the neck and face veils are red, hot to the touch. At mouth examination there is redness of the pharynx wall, sky arches, the mucous membrane of the soft palate, tonsils. Occipital, cervical, submandibular lymph nodes may be enlarged, more often if the causative agent is of mumps virus.
Meningeal symptoms allowing diagnosis of meningitis are manifested by pain in the neck and along the spine, neck muscles rigidity. Kernig’s symptoms often develop (inability to straighten the leg bent at the knee). During the week, meningeal symptoms regress, body temperature returns to normal state. However, asthenia and headache persist for two weeks. In young children, especially in newborns meningitis may be associated with inflammation of the heart muscle, myocarditis. Often there are catarrhal symptoms: rhinitis, pharyngitis, laryngitis.
Usually due to the classic symptoms of meningitis diagnosis is beyond doubt. Lumbar puncture and examination of cerebrospinal fluid by polymerase chain reaction (PCR) are performed in order to isolate the pathogen.
In the early days of the disease in the cerebrospinal fluid there may be leukocytosis, testifying in favor of bacterial meningitis nature. For the differential diagnosis of conduct microscopic examination is made. The absence of bacteria in the smear indirectly confirms a viral etiology. Dynamic study of cerebrospinal fluid in the next 12-24 hours shows an increase in the number of lymphocytes, which speaks in favor of the viral nature of the disease.