SOME liken it to another Japanese invasion; however, instead of able-bodied chinky–eyed soldiers with fixed bayonet menacing the populace, the invading force is a formidable virus which if not aggressively stopped, may lead to a serious illness affecting the central nervous system of infants and young children.
First things first. The central nervous system is composed of the brain and the spinal cord while the other division of the peripheral nervous system, composed of the terminal branches of the twelve pairs of cranial nerves and the 31 pairs of spinal nerves. The covering of the brain substance - brain parenchyma - is the meninges with its three layers, from outside going inside dura mater, arachnoid and pia mater. When the meninges are infected and inflamed, it is called meningitis, which can be caused by bacteria, virus and even fungi.
Encephalitis, which is the major pathology of Japanese encephalitis is infection and inflammation of the brain substance; encephalomyelitis if there is brain and spinal cord involvement. The terms “West Nile, Japanese” refer to the locality where there was a dramatic, significant incidence of the viral disease which caught worldwide concern and attention.
Viral brain infections can produce different sets of symptoms, with some just mild like fever and a general feeling of not-well. Encephalitis disrupts normal brain function causing personality changes, seizures and convulsions, weakness of one or more parts of the body, confusion and sleepiness that could lapse into coma.
At this juncture, it is important to emphasize that at first, doctors have difficulty distinguishing bacterial meningitis from viral encephalitis. A spinal tap, also called lumbar puncture is done, which in encephalitis, there may be a significant increase in white blood cells but no microbe is found in the specimen. It is a fact in medicine, especially in the field of microbiology that it is rather difficult to culture, much less isolate and identify viruses, thus doctors rely on history and physical examination plus the constellation of signs and symptoms of the patient.
Of course, there are high-tech diagnostic procedures like immunologic tests to measure antibodies against viruses. To eliminate probable causes, the physician may order cat scan or even an MRI-magnetic resonance imaging- to be sure that the signs and symptoms are not caused by brain abscess, stroke or structural problems like tumor, aneurysm or a hematoma-blood clot.
As a rule, or in general, in adults tend to recover more quickly especially so if they receive early and adequate treatment. Young children tend to recover over a long period while infants are more likely to have permanent damage, and this is probably explained by the fact that 80 percent of the brain is developed by birth, another 10 percent during first year of life and the remaining 10 percent up to 4 – 5 years of age.
The Department of Health is presently involved in an aggressive campaign for immunization against Japanese encephalitis for infants and children from 9 to 59 months of age.