A monthly index measuring the distribution of a species of mosquito known for carrying the dengue virus surged to an average 10.2% from 1% in April, according to surveys by the Hong Kong Food and Environmental Hygiene Department (FEHD). Nine districts reached or exceeded the alert level of 20%, according to a government release.
These are Tseung Kwan O North (32.8%), Kowloon Bay (29.8%), Sheung Shui (29.3%), Fanling (25.9%), Wong Tai Sin Central (23.4%), Deep Water Bay and Repulse Bay (22.6%), Tseung Kwan O South (21.3%), Lok Fu West (21.3%) and Lam Tin (20.4%).
The FEHD said it was very concerned about mosquito infestation, and an inter-departmental anti-mosquito response mechanism has been activated in the alerted areas. Effective mosquito prevention and control measures will have to be carried out by various stakeholders in the districts.
The government departments concerned have also stepped up inspections and measures to enhance environmental hygiene in areas within their ambits to eliminate existing and potential mosquito breeding grounds.
The concern is about Aedes albopictus, a species of mosquito that can transmit dengue fever and the Zika virus.
Hong Kong recorded one confirmed locally contracted case of dengue fever last year, as well as five cases of Japanese encephalitis. One imported Zika infection was also recorded.