The Hanoi Department of Health reported the first case of Japanese encephalitis in the city this year, a 12-year-old boy from Phuc Tho district. The boy showed symptoms of high fever and headache on June 16, and the next day he had a stiff neck and was unable to walk, prompting his family to take him to the National Children’s Hospital. Tests confirmed that he had the Japanese encephalitis virus in his cerebrospinal fluid. The boy had received four shots of the Japanese encephalitis vaccine, with the last one given on June 15, 2019.
Japanese encephalitis is a serious disease caused by the Japanese encephalitis virus, with strong transmission by the Culex tritaeniorhynchus mosquito, which is active in Vietnam especially from March to July. This mosquito species is prevalent in the delta and midland areas and is the primary vector for Japanese encephalitis in the country. The disease mainly affects children, causing encephalitis and meningitis with a high mortality rate and long-term consequences.
The symptoms of Japanese encephalitis can be challenging to detect early as they are similar to other infections. However, as the disease progresses, symptoms such as high fever, nausea, vomiting, headache, and lethargy become more apparent. If left untreated, the disease can rapidly advance to seizures, coma, and even death within a few days. Additionally, it can lead to long-term neurological complications that impair the patient’s ability to communicate and work, becoming a burden on their families and society.
Vaccination is currently the most effective way to prevent Japanese encephalitis. The Department of Preventive Medicine recommends a series of three basic doses starting after one year of age, with additional booster shots every few years until the child reaches 15 years old. By following the vaccination schedule, individuals can significantly reduce their risk of contracting this potentially life-threatening disease.