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The Chiayi County Health Bureau announced today (16th) the first case of Japanese encephalitis reported this year in the county. The patient is a middle-aged man from Dalin Township who began to show fever symptoms on the 7th and sought emergency medical care due to worsening conditions on the 9th. During his emergency treatment, medical staff observed his slowed speech and altered consciousness, which led to further testing and a confirmation of Japanese encephalitis. The patient is currently hospitalized and continues to receive treatment.

In response to this case, the Health Bureau has installed mosquito traps around the patient's activity area, particularly near pig farms, and is stepping up public health education initiatives. They are also urging medical institutions to enhance their reporting of Japanese encephalitis cases. The peak season for Japanese encephalitis typically runs from May to October, with June and July being particularly high-risk months. Individuals of all ages are at risk of infection, thus the Health Bureau is calling on residents to implement mosquito prevention measures. Adults visiting high-risk areas are encouraged to consider vaccination at their own expense, while children should complete the recommended two doses of the vaccine on schedule.

Investigations revealed that the patient works in the livestock industry and has no history of recent travel abroad. The Health Bureau is conducting surveys of the surrounding environment of the patient’s residence, which includes pigeon coops, pig farms, and irrigation ditches in rice fields—identified as high-risk areas. No vaccination records against Japanese encephalitis were found for the patient. The bureau has already installed mosquito traps at these locations and is providing educational outreach to local pig farmers, encouraging them to seek vaccination consultations at the Chiayi Chang Gung Memorial Hospital’s travel clinic.

The primary vectors for Japanese encephalitis are species such as the Culex tritaeniorhynchus, Culex pipiens quinquefasciatus, and Culex annulatus. These mosquitoes typically breed in rice paddies, ponds, and irrigation ditches. Their peak feeding activity occurs during dusk and dawn. Most individuals infected with the virus do not exhibit obvious symptoms; however, those who do may experience headaches and fever. In severe cases, symptoms may escalate to altered consciousness, inability to identify people or surroundings, general weakness, and in some instances, coma or death.

The most effective method of preventing Japanese encephalitis is through vaccination. In our country, the routine vaccination schedule for children is to administer the first dose at 15 months of age and the second dose 12 months later. The Health Bureau reminds parents to ensure their eligible children receive vaccinations at local health offices or contracted clinics on schedule to prevent severe complications from potential infections.

Health Bureau Director Chao Wen-Hua emphasized the importance of individual protective measures, advising people to avoid outdoor activities during peak mosquito activity times, especially at dusk and dawn near pig farms and rice paddies where these mosquitoes breed. If avoiding these areas is not possible, wearing light-colored long-sleeved clothing and applying government-approved insect repellents (containing DEET, Picaridin, or IR3535) on exposed skin is recommended. Additionally, individuals are advised to install screens on windows and doors at home and use mosquito nets while sleeping. Adults who feel they may be at risk of infection are encouraged to visit a travel medicine clinic for assessment and consider self-paying for vaccinations.