Pigs may be inoculated to help prevent Japanese encephalitis in people, however there is no need for the public to be vaccinated at this stage.

This was the message today from Centre for Health Protection Controller Dr Leung Pak-yin who said inoculations for people were not yet worthwhile as the chances of side effects are high with Japanese encephalitis vaccinations.

Despite the inoculation proposal, Dr Leung said the most effective way to prevent the disease is to stop mosquito breeding by removing stagnant water and keeping the environment clean.

The centre's consultant Dr Thomas Tsang said officers are still tracing the source of infection of the second Japanese encephalitis case in Palm Springs, Yuen Long. So far, 643 residents have been interviewed and 110 blood samples taken, and 98 enquiries received on the 2575 1848 hotline.

Dr Tsang said the centre will conduct serology tests across Hong Kong to ascertain the risk of Japanese encephalitis contraction.

The Food & Environmental Hygiene Department has stepped up anti-mosquito measures in the areas near the patient's residence. Three nearby piggeries have been inspected and their conditions are satisfactory.

Four areas in the vicinity have been identified as breeding grounds for Culex tritaeniorhychus, the key vector of Japanese encephalitis. Anti-mosquito work around Palm Springs, including nearby abandoned fields and dense vegetation, will be strengthened.