Hong Kong health officials announced the investigation into the first suspected local case of Japanese encephalitis (JE) this year, and hence again urged the public to maintain strict environmental hygiene, mosquito control and personal protective measures both locally and during travel.

Hong Kong/CIA
Hong Kong/CIA

“Although the case had travel history during the incubation period, the duration of stay was short. It cannot be ruled out that the case was locally acquired at this stage. As a precautionary measure, we are working closely with the Food and Environmental Hygiene Department (FEHD) to assess and prevent any possible spread of infection,” Dr Leung Ting-hung said.

According to the patient’s family, the male patient, aged 68 with underlying illness, developed fever and poor appetite on June 23 and acute confusion on June 24. He was then taken to Ha Kwai Chung General Out-patient Clinic for medical attention and was transferred and admitted to Princess Margaret Hospital for further management. He is now in the Intensive Care Unit in critical condition.

Both his cerebrospinal fluid and blood sample tested positive for antibodies against JE upon testing by the Centre for Health Protection’s (CHP) Public Health Laboratory Services Branch.

Initial inquiries revealed that, according to his family, he had traveled to Kaiping and Xinhui, Guangdong, on June 11 and returned to Hong Kong on June 12. His home contacts have remained asymptomatic and have been put under medical surveillance. The CHP is conducting further inquiries for more information on his travel history, local movements and exposure.

In addition, the patient lives in Wah Yuen Chuen, 12 Wah King Hill Road, Kwai Chung. According to officials, there are water streams and water bodies in the vicinity, while according to Agriculture, Fisheries and Conservation Department (AFCD), there are wild birds in the area but there are no records of wild pigs or registered pig farms nearby.

“Upon notification and laboratory confirmation, the CHP immediately commenced epidemiological investigations and promptly informed the FEHD and the AFCD for vector investigation. We also informed the relevant management office and the Home Affairs Department for their follow-up. Investigations and health education in the vicinity where the patient frequented are proceeding,” Dr Leung added.

Taiwan map/CIA
Taiwan map/CIA

In Taiwan, health officials reported an additional seven cases of JE (5 in Tainan City and 2 in Yunlin County) during the past week, bringing the country total to 10. This compares to nine cases during the same period in 2014.

The new five cases confirmed in Tainan City respectively reside in Xinshi District, Guantian District, Jiangjun District, Annan District, and Jiali District. The two new cases confirmed in Yunlin County both reside in Douliu City. The cases are aged between 42 and 59 and their onset dates range between June 4 and June 22.

Their symptoms include fever and change of consciousness. As of now, all 7 cases are hospitalized for treatment. According to the epidemiological investigation, all 7 cases had not recently traveled overseas, but there are pig farms, pigeon farms and rice paddy fields within 2 km of the cases’ residences. Hence, it is determined that the source of infection is somewhere around the case’s residence.

According to Taiwan CDC’s surveillance data, transmission of Japanese encephalitis in Taiwan occurs annually between May and October and it usually peaks between June and July.