What causes encephalitis?

Currently there are many causes of encephalitis, some of which are controllable. Understanding and understanding the causes of disease helps the process of prevention and treatment go better.

Mosquito-borne meningitis includes a group of pathogenic viruses that penetrate briefly into parts of the brain, spinal cord and meninges, causing acute inflammation there. Some of the signs and symptoms of these diseases are similar. However, the severity and progression of each disease will vary. Most people infected with the virus have no symptoms. Mild cases, often with headache, fever or aseptic meningitis. Severe cases, with acute onset at onset, high fever, headache, meningeal signs, stupor, coma, tremor, disorientation, sometimes convulsions occur especially in young children. and spastic paralysis.
Mortality rates range from 0.3% to 60%, of which the highest rates are due to Murray Valley encephalitis (MVE), Japanese encephalitis and eastern equine encephalitis (EEE). The incidence will leave neurological sequelae of mosquito-borne viral encephalitis occurring with different frequencies. This depends on the age of the patient and the causative agent. The disease left the most severe neurological sequelae in children with EEE, Japanese encephalitis (JE) and western equine encephalitis (WEE).
The most common group of mosquito-borne encephalitis viruses are JE virus, EEE virus, WEE virus, Saint Louis encephalitis virus (SLE), Rocio encephalitis virus (RE), Jamestown Canyon encephalitis virus (JCE), MVE virus, virus Lacrosse encephalitis (LE), California encephalitis virus (CE) and snowshoe hare virus (SSHE).

There are many different viruses that can cause encephalitis. They are classified into three groups: childhood viruses, common viruses, and arboviruses.
The most common virus that causes encephalitis in developed countries is herpes simplex. This type usually travels through a nerve to the skin. This is where cold sores are caused. In rare cases, the virus travels to the brain. This form of encephalitis usually affects the temporal lobe - the part of the brain that controls memory and speech. In addition, it is also possible to affect the frontal lobe, the part that controls emotions and behavior. Herpes encephalitis can be very dangerous and lead to serious brain damage and even death. Some other common viruses that can cause encephalitis include: HIV, cytomegalovirus, mumps, Epstein-Barr virus.
Encephalitis is transmitted by mosquitoes and ticks. These are arthropods (arthropods) hence the name arbovirus (Arthropod-borne virus). Some organisms that transmit disease from one host to another are called vectors. Mosquitoes are a very important disease vector. Some Southeast Asian countries (including Vietnam), Korea, India, China, Taiwan, Russia... every year there is an epidemic of Japanese encephalitis with a high number of people infected.
Very rare cases of childhood viral encephalitis, including: chickenpox (very rare), measles, rubella.

Depending on the type of virus that causes the disease, the way the virus enters varies. Many viruses can be transmitted from person to person. Some cases of encephalitis are caused by a reactivation of a virus in the body, such as the herpes simplex virus. Mosquitoes and other insects transmit disease through entry from bites. Rabies is transmitted by the bite of some animals. With some viruses, such as cytomegalovirus (CMV) and varicella-zoster virus (VZV), immunodeficiency plays an important role in disease pathogenesis.
Normally the virus replicates outside the central nervous system. It then enters this system by blood or by way of nerves (herpes simplex virus, rabies and varicella-zoster virus) and olfactory route (herpes simplex virus). The causes of delayed cases of encephalitis such as progressive multifocal leukoencephalopathy (PML) and subacute sclerosing panencephalitis (SSPE) after measles are not fully understood.
Therefore, a person can become infected with the virus through the following modes of transmission:
Infected insects (such as mosquitoes or ticks) and animals, can transmit some viruses directly into the bloodstream through a bite. A cough or sneeze from an infected person releases the virus into the air. Then the other person inhales. Eating contaminated food. Spread the virus through touching an infected person. Some evidence suggests that cases of viral encephalitis are caused by an inactive viral infection (such as the herpes simplex virus) becoming active again.

Factors that increase the risk of viral encephalitis include:
Age: Some encephalitis is more common and/or more severe in children or the elderly. Immunocompromised: Patients who are immunocompromised by disease or treatment or by organ transplantation are at higher risk. Season of the year: The hot and humid summer months are the breeding season for birds and mosquitoes, so arbovirus encephalitis is higher. In winter-spring, enteric viral encephalitis may be more common. Geographical regions: Tropical regions are often at higher risk of encephalitis, especially encephalitis caused by arboviruses. Outdoor activities: People who have a lot of outdoor activities such as gardening, raising pigs, or studying birds, meaning that there is a high risk of exposure to mosquitoes, are more susceptible to disease.

Health propaganda and education: It is necessary to provide the people with information about viral encephalitis, virus reservoirs and mosquito vectors so that people can detect the disease early. Take measures to prevent and kill mosquito vectors by yourself.
Houses and gardens must be clear, clean, and free from waste containing stagnant water to eliminate mosquitoes, larks and other insects. Leave the animal stables away from the house, regularly clean the animal cages, smoke or spray insecticides to kill mosquitoes. Use metal mosquito nets in windows and doors and sleep under mosquito nets. If there are many mosquitoes or when necessary, insecticides and insecticides can be used. Locally endemic diseases such as JE disease, which can immunize humans or domestic animals (such as pigs to JE) are reservoirs of the transmissible virus. Vaccinate travelers to an area where viral encephalitis is endemic and laboratory workers associated with the virus and its vectors. When there are signs of encephalitis, you should go to a reputable medical facility for early examination and treatment, to avoid long-term treatment difficulties and many dangerous complications. Vinmec International General Hospital is a high-quality medical facility in Vietnam with a team of highly qualified medical professionals, well-trained, domestic and foreign, and experienced.
A system of modern and advanced medical equipment, possessing many of the best machines in the world, helping to detect many difficult and dangerous diseases in a short time, supporting the diagnosis and treatment of doctors the most effective. Therefore, patients can be assured of the results of examination and treatment at Vinmec.