Zika outbreak: hearing loss found in 6% of Brazilian babies in study

A study in Brazil of 70 babieswhose mothers had confirmed Zika infections found that nearly 6per cent had hearing loss, adding a new complication to the listof ills the virus can cause when women are infected duringpregnancy.

The Brazilian study, published on Tuesday in the U.S.Centers for Disease Control and Prevention's weekly report on
death and disease, confirmed less rigorous reports of deafnessamong infants born to mothers with Zika infections.

The finding is part of an effort to fully characterize theharm caused by the Zika virus during pregnancy. The virus isbest known for causing the severe birth defect microcephaly,characterized by undersized heads and underdeveloped brains. Butother studies have shown that Zika can cause other brainabnormalities, vision problems and joint deformities.

In the latest study, a team atthe Oswaldo Cruz Foundation in Pernambuco,Brazil, examined records from 70 infants with microcephaly whosemothers had laboratory-confirmed Zika infections duringpregnancy.

They found that nearly 6 per cent had hearing loss withoutany other plausible cause.

Several other viral infections during pregnancy can causehearing loss, including rubella and cytomegalovirus, or CMV,
infections. The current study adds Zika infection to that list.

WHO emergency committee for Zika meets Thursday

Scientists say Zika should now be considered a risk factorfor hearing loss, and children who were exposed during pregnancybut have normal hearing at birth should be screened regularlyfor delayed or progressive hearing loss.

Meanwhile, the World Health Organization(WHO) said on Tuesday that its Emergency Committee on Zika wouldmeet on Thursday to review the outbreak's evolution andneurological birth defects linked to the mosquito-borne virus.

The panel of independent experts led by Dr. David Heymann,which last met on June 14, convenes every three months to assessprogress in the fight against the disease and malformations including microcephaly, a birth defect marked by small head sizethat can lead to severe developmental problems in babies.

• 'He's a warrior': Brazilian parents face challenges of raising babies with Zika
• Zika infection found in newborns without microcephaly

Elsewhere, the U.S. Centers for Disease Control and Prevention,Australia, Taiwan and SouthKorea advised pregnant women and those attempting to getpregnant to avoid travel to Singapore.

Singapore'soutbreak and the warnings come as a potential blow totourism in one of the world's busiest travel hubs, which isalready struggling to recover from a slump amid tepid globalgrowth.

Singapore reported its first case of locally-transmittedZika at the weekend, and the number of reported infections ofthe mosquito-borne virus has since jumped to 56. At least threedozen of those have since made a full recovery.

Screening in Southeast Asia

In mostpeople infected with Zika virus, the reaction ismild, and 80 per cent have no symptoms.

The Zika virus was detected in Brazil last year and hassince spread across the Americas. It poses a risk to pregnantwomen because it can cause severe birth defects. It has beenlinked in Brazil to more than 1,800 cases of microcephaly, arare birth defect where babies are born with abnormally smallheads and brains.

The 56 confirmed cases in Singapore include only one woman.

Taiwan, Australia and South Korea advised pregnant women andthose planning pregnancy to postpone trips to Singapore. Thosereturning from the country should avoid pregnancy for twomonths. South Korean travellers will receive text messages withthe warning when they arrive in Singapore.

• Canadian baby with Zika developing normally, chief doctor says

Regional health experts said the Zika virus is likely to besignificantly under-reported across tropical Southeast Asia as
local health authorities fail to conduct adequate screening.

As of Aug. 25, 232 travel-related cases, twosexually transmitted cases and threereports of maternal-to-fetal transmission have been detected in Canada.

There have been no reported cases of individuals infected by mosquitoes in Canada. Travellers are advised to take precautions against mosquito bites at all times.