Brazil's health minister announced new measures to curb the Zika virus Tuesday, but was also quoted as saying the country's battle to eradicate mosquitoes blamed for spreading the virus is already being lost.

Marcelo Castro said that nearly 220,000 members of Brazil's Armed Forces would go door-to-door to help in mosquito eradication efforts, according to Rio de Janeiro's O Globo newspaper. It also quoted Castro as saying the government would distribute mosquito repellent to some 400,000 pregnant women who receive cash-transfer benefits.

All major Brazilian dailies quoted Castro as saying the country is "badly losing the battle" against the Aedes aegypti mosquito that transmits Zika, dengue, chikungunya and yellow fever.

"The mosquito has been here in Brazil for three decades, and we are badly losing the battle against the mosquito," Folha de S. Paulo newspaper quoted him as saying as a crisis group on Zika was meeting in the capital, Brasilia.

Emails to Castro's office for comment were not immediately answered.

About 80 per cent of people infected with Zika virus show no symptoms. Those who do may have fever, headache, pink eye and rash, along with joint and muscle pain.  The illness is typically mild and lasts a few days.

Pregnancy cautions

Worry about the rapid spread of Zika has expanded across Brazil and the hemisphere beyond.

Repellent has disappeared from many Brazilian pharmacies and prices for the product have tripled or even quadrupled where it's still available in recent weeks since the government announced a suspected link between Zika virus and microcephaly, a rare birth defect that sees babies born with unusually small heads and can cause lasting developmental problems.

Nearly 4,000 suspected cases of microcephaly have been reported since October, compared with fewer than 150 cases in the country in all of 2014. It's not known how many of these microcephaly cases are associated with Zika virus infection. Research is underway to better understand the association.

Argentina authorities say they are investigating a possible case of Zika infection. It would be a first for the nation that shares a border with Brazil. Santa Fe Health Department official Andrea Uboldi tells La Red radio that the man is in the city of Rosario and had recently visited Brazil.

Both Brazil's Zika outbreak and the spike in microcephaly have been concentrated in the poor and underdeveloped northeast of the country, though the prosperous southeast, where Sao Paulo and Rio de Janeiro are located, are the second hardest-hit region. Rio de Janeiro will host the Aug. 5-21 Olympic games.

On Tuesday, officials in Rio also ramped up their fight against the Aedes aegypt mosquito, dispatching a team of fumigators to the Sambadrome, where the city's Carnival parades will take place next month. Governor Luiz Fernando Pezao was to be on hand for a ceremonial handover of around 30 vehicles to help poor Rio suburbs fight the spread of the mosquito, his team said.

Officials have also pledged to redouble mosquito eradication efforts during the Olympics.

Concern for pregnant travellers 

Canadian and U.S. health authorities advise pregnant women to consider avoiding or postponing travel to South and Central America and parts of the Caribbean. 

On Tuesday, the U.S. Centers for Disease Control and Prevention published interim guidelines for health care professionals on caring for infants born to mothers who travelled or lived in an area with Zika virus transmission.

The guidelines include monitoring fetal ultrasounds and testing infants with signs of microcephaly.


The Brazilian government announced a suspected link between Zika virus and microcephaly, a rare birth defect that sees babies born with unusually small heads and can cause lasting developmental problems. (Mario Tama/Getty Images)

American Airlines began refunds Monday for pregnant passengers holding tickets to El Salvador, Honduras, Panama or Guatemala.

The airline announced Wednesday it has expanded its refunds for pregnant customers visiting areas impacted by the Zika virus to include Puerto Rico, Martinique and nine countries in Central and South America and the Caribbean, a spokesman said.

With files from CBC News and Reuters