BANGKOK • The Thai health authorities yesterday reported the first confirmed cases in South-east Asia of microcephaly linked to mosquito-borne Zika, as the World Health Organisation (WHO) urged action against the virus across the region.
"Two of the three infants (tested) had microcephaly due to the Zika virus," said Health Ministry official Wicharn Pawan.The ministry said tests remain inconclusive as to whether Zika was linked to the third infant's condition.
An adviser to the Department of Disease Control, Dr Prasert Thongcharoen, declined to say where the cases were found but officials have said they were not in Bangkok.
WHO said the cases were the first of Zika-linked microcephaly in South-east Asia, and the virus infection represented a serious threat to pregnant women and their unborn children. "Countries across the region must continue to strengthen measures aimed at preventing, detecting and responding to Zika virus transmission," Dr Poonam Khetrapal Singh, the WHO's regional director, said in a statement.
Microcephaly in babies can lead to respiratory problems and lifelong difficulties, including intellectual impairment. The connection between Zika and microcephaly came to light last year in Brazil, which has confirmed more than 1,800 cases of microcephaly it considers to be related to Zika infections in mothers.
Zika has spread extensively in Latin America and the Caribbean over the past year or so, and more recently it has been detected cropping up in South-east Asia. Thailand has confirmed 349 Zika cases since January, including 33 pregnant women.
The US Centres for Disease Control and Prevention (CDC) said on Thursday that people should consider postponing travel to Thailand as well as Brunei, Myanmar, Cambodia, Indonesia, Laos, Malaysia, Maldives, the Philippines, Timor Leste and Vietnam because of the Zika risk.
The CDC issued a travel warning for Singapore in August. Singapore has recorded 392 Zika cases this year, including 16 pregnant women. Earlier, Singapore's Health Ministry said tests found that the Zika virus here likely evolved from the Asian strain, which means it was not imported from South America.
Thailand's confirmation of Zika- linked microcephaly comes ahead of China's week-long "Golden Week" holiday, with Thailand expecting 220,000 Chinese visitors, said Tourism Authority of Thailand governor Yuthasak Supasorn.
Some health experts have accused Thai officials of playing down the risk of Zika to protect the country's thriving tourist industry, but Dr Prasert dismissed that. "Thailand is not hiding anything and is ready to disclose everything," he said.
There is no vaccine or treatment for Zika, a virus spread mainly by mosquitoes. An estimated 80 per cent of people infected have no symptoms. There are also no specific tests to determine if a baby will be born with microcephaly, but ultrasound scans in the third trimester of pregnancy can identify the problem, according to the WHO.
Meanwhile, a study published on Thursday in the Cell Host & Microbe journal said the Zika virus can infect and alter cells in the human nervous system that are crucial for formation of bones and cartilage in the skull. Zika has already been shown to attack foetal brain cells known as neural progenitor cells - a type of stem cell that gives rise to various kinds of brain cells.
The death of these cells is what disrupts brain development and leads to microcephaly in babies whose mothers were infected with Zika during pregnancy.
American scientists conducted this latest study by infecting human cells with Zika in the lab.
But the team, co-led by Dr Joanna Wysocka, a chemical and systems biologist at the Stanford University School of Medicine, said follow-up research would be needed to look for any evidence that the virus' effect on the cells would be enough to cause microcephaly.
REUTERS, AGENCE FRANCE-PRESSE