Mosquito infestation in Hong Kong reaches ‘alert’ level, index shows, prompting fears of dengue and Zika virus transmission

An index that measures growth in the numbers of a type of mosquito that could transmit dengue fever and the Zika virus has exceeded an “alert” level in eight districts and reached a new high for the city overall.

A spokesman for the Food and Environmental Hygiene Department, which monitors the growth of the Aedes albopictus species, has warned Hongkongers to “remain vigilant” to dangers posed by the pests as dengue fever remains prevalent in neighbouring countries and rainy summer weather brings favourable conditions for breeding.

According to the latest figures released by the department, the Ovitrap Index, which records the number of eggs laid by the mosquitoes, rose to a reading of 13.5 per cent citywide last month from 9.3 per cent in May.

Among 52 locations surveyed for the index, eight exceeded the “alert” level of 20 per cent. Tseung Kwan O North was highest at 35 per cent, followed by Tsing Yi North. When compared with index readings from June last year, Tsuen Wan Town, which recorded 26.8 per cent last month, saw the biggest rise.

An index reading between 20 and 40 per cent means infestation of the mosquito has “exceeded one-fifth of the area” in question.