Hong Kong woman who travelled to South America becomes first imported Zika case of the year

A 31-year-old woman has been confirmed to be Hong Kong’s first imported Zika virus case this year, prompting the government to implement emergency mosquito control measures.

The patient, who was in a stable condition on Wednesday, was receiving treatment in an isolation ward in the Alice Ho Miu Ling Nethersole Hospital in Tai Po. She was admitted there on Monday.

Last year, there were two imported Zika cases.

The woman, who is said to have been in good health and lives in Fortune Plaza in Tai Po, has been suffering headaches, a sore throat, nausea and vomiting since last Friday after she returned from a two-week trip with three family members to visit relatives in Peru and Ecuador in South America.

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The World Health Organisation says Zika is present in the two countries.

The disease is caused by a virus transmitted primarily by Aedes mosquitoes.

The patient could not recall having been bitten by mosquitoes during her trip or in Hong Kong, according to the Centre for Health Protection, which is investigating the case.

Zika can spread from a pregnant woman to her baby. This can result in microcephaly, severe brain malformation and other birth defects. The woman in question is not pregnant.

The centre’s controller, Dr Wong Ka-hing, was satisfied that the risk of widespread local transmission was low because the woman had mainly stayed at home before being admitted to hospital.

“Her travel [partners] and home contacts have remained asymptomatic so far,” Wong said.

On why the woman slipped through the health screening system for arriving passengers at Hong Kong International Airport, Dr Wong said: “Routine health surveillance of the body temperature of inbound travellers at all [border checkpoints] is ongoing. However, infected persons are mainly asymptomatic.

“We urge those arriving from Zika-affected areas to apply insect repellent for at least 21 days upon arrival to reduce the risk of transmission.”

In the wake of the latest case, the Food and Environmental Hygiene Department will conduct an anti-mosquito operation on Thursday near the woman’s home as well as at the hospital.

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Earlier on Wednesday, the department announced that the monthly ovitrap index for the Aedes albopictus mosquito for March was 0.1 per cent, up from zero in the previous month.

Despite the rise, the index remained very low, which indicated infestation was not extensive, according to Lee Ming-wai, the department’s pest control officer.

But Lee said the department would stay alert as the rainy season would soon arrive.

Aedes albopictus is a kind of mosquito that can transmit dengue fever and Zika.