Summary of Japanese b encephalitis virus

Pathogenic characteristics

Japanese b encephalitis virus (Japanese encephalitis virus comes, JEV) belong to the yellow virus (Flavivirus), is a major mosquito-borne viruses, can cause human and animal central nervous system infection. The virus was found in Japan, hence the name. Virus particles are spherical, about 20 to 40 nm in diameter, as the single stranded RNA viruses, outside have similar lipid envelope, the surface has hemagglutinin, able to agglutinate chicken red blood cells. Virus in cell proliferation, sensitive to temperature, ether, acid and other conditions, can be in milk mouse tissues to extend, can also be in chicken embryos, monkey kidney cells, embryo cells, such as cell growth.

epidemic

Japanese b encephalitis mainly popular in Asia, especially in southeast Asia, South Asia and east Asia in the summer and fall. Virus is spread by mosquitoes, related to migratory birds, and more common in rural areas, and rice paddies environment. Children and teenagers are people at high risk of infection, because their immune system is relatively weak. Adults due to certain immunity, infection rate is low.

Route of transmission

Virus is spread mainly by culex mosquito bites. After the mosquito bite the animals with the virus, then bite people, makes the virus to invade the body. Culex are the main media, they are in the evening or night activities, and reproduction in the ponds, rivers or irrigation paddy fields.

clinical signs and symptoms

Infection after the incubation period is usually 4 to 14 days. Most infected people have no symptoms or lighter, but a few will appear serious encephalitis symptoms, such as high fever, severe headache, nausea, vomiting, disturbance of consciousness, convulsions and coma. Case fatality rate is higher, about 25%, and there may be a legacy of the nervous system, such as aphasia, paralysis and mental disorders.

Pathological changes

Virus invasion of the central nervous system can lead to meningitis, encephalitis, and myelitis lesions. Pathological changes including vascular endothelial cell damage, nerve cell degeneration, necrosis and local glial cell hyperplasia, etc. Severe cases may be due to cerebral edema, cerebral hernia and death.

Diagnostic methods

Diagnosis mainly depends on the serological examination and etiology examination. Blood routine examination showed leukocytosis, mainly neutrophils. Cerebrospinal fluid examination may show increased pressure, leukocytosis, protein levels may rise. Imaging examination such as MRI may show brain lesions. Such as blood clotting inhibition test and serologic testing neutralization test can specific antibody detection in the first week of the disease.

Prevention and control measures

Prevention of encephalitis b vaccine is one of the most effective measures, especially in high-risk groups such as children and farmers. In addition, anti-mosquito measures is also very important, including wearing long-sleeved clothes, such as the use of mosquito nets and insect repellent. Treatment, there is no special effects of antiviral drugs, mainly support therapy, such as temperature, pain, etc., and deal with complications timely.

conclusion

Japanese b encephalitis virus is a kind of main mosquito-borne viruses, can lead to severe central nervous system infection, mortality and sequelae rate is higher. The key to prevention and control is vaccination and anti-mosquito measures. When the outbreak, early diagnosis and treatment is essential, at the same time to strengthen the monitoring, publicity and education and mosquito-borne prevention and control work is also the necessary control measures.