The condition of a 20-year-old Tin Shui Wai woman with Japanese encephalitis improved from serious to stable yesterday, but her neighbours called for the hygiene department to step up mosquito controls.
A large-scale anti-mosquito-spraying operation was carried out in the Yuen Long district yesterday, while 21 residents were given blood tests at a health department station.
One expert speculated that the deadly mosquito-transmitted disease had already been spreading in the area.
University of Hong Kong microbiologist Ho Pak-leung said that statistically, only one in 300 people infected by the virus would develop serious symptoms, meaning the scope of infection could be larger.
In most cases, only a mild infection occurs, causing slight fever and a headache.
However, local residents 'were in a panic after the case was announced', district councillor Ken Chow Wing-kan said.
Mosquito controls had been carried out just once a month around the estate where the patient lives, a known hygiene black spot, said Chow.
