By Franco Ordonez

McClatchy Washington Bureau

(TNS)

WASHINGTON — An obscure mosquito-borne virus that has already prompted warnings in Central America to avoid getting pregnant and is thought responsible for thousands of birth defects in Brazil has now reached the United States, according to health officials.

The Centers for Disease Control and Prevention said U.S. doctors should test newborns who show signs of the Zika virus, especially in states such as Florida, where mosquitoes are a daily nuisance. The advisory came the same day that Arkansas officials confirmed that they had diagnosed someone there with the virus and warned it was possible that the virus had infected the local mosquito population.

The dual announcements mark the latest twist in a burgeoning public health crisis that evokes memories of the 2014 Ebola crisis, when a slow international response to an unusually virulent outbreak of disease ended up costing the lives of thousands.

The threat from the Zika virus, which causes fever, rash and joint pain, is not so much to those who contract it, however, but to their unborn children, who often suffer from microcephaly, a birth defect characterized by an unusually small head and developmental problems. As many as 4,000 infants in Brazil are thought to have suffered the condition because their mothers had been infected with Zika.

Zika has already been found in 21 countries and territories in the Western Hemisphere. It has spread so quickly that world health officials had warned that it was only a matter of time before it reached the United States.

Francis Collins, the director of the National Institutes of Health, on Tuesday called Zika an emerging threat and urged more research into its treatment and prevention. He said a recent study found that more than 60 percent of the U.S. population — about 200 million Americans — live in areas where the virus could spread.

“In addition, another 22.7 million people live in humid, subtropical parts of the country that might support the spread of Zika virus all year-round, including southern Texas and Florida,” Collins wrote in a blog post. “Already, there are reports of local spread of the virus within Puerto Rico and of travelers returning to the U.S. with the Zika infection.”

The Aedes aegypti mosquito carrying Zika is the same one that transmits dengue and chikungunya viruses, which have caused outbreaks in Florida and other parts of the United States.

The warnings should be a wake-up call for Florida and other Southern states, which are more vulnerable because of their large mosquito populations, said Walter Tabashnick, former director of the Florida Medical Entomology Laboratory. He pointed to how dengue fever struck Key West in 2009, infecting 27 people, and then again in 2011, infecting 66 people.

All that is needed for the virus to spread is for some Florida mosquitoes to bite an infected person who has traveled to the United States, Tabashnick said. The mosquitoes can then transmit the virus to others.

“There should be a public outcry,” said Tabashnick, who is a professor at the University of Florida at Vero Beach.

“Are we waiting for the first babies? By then it’s too late.”

Since Brazil reported its first case last May, Zika has affected as many as 1.3 million Brazilians, and more than 220,000 soldiers have been mobilized to spray for mosquitoes. More than 13,000 people have been infected in Colombia and roughly 500 in El Salvador, where health officials have taken the dramatic step of advising women to delay getting pregnant until 2018.

Authorities in Ecuador and Colombia have also recommended that couples avoid pregnancy but for shorter periods.

“Zika virus has become a priority for the president himself and for the minister of health,” said Juan Carlos Pinzon, Colombia’s ambassador in Washington. He added that his government has launched a campaign to educate the population on how to reduce the spread of the virus.

Colombia, with one of the stronger local economies, may be better suited to respond to the health crisis than more cash-strapped countries such as El Salvador, where health services are extremely precarious.

“There is not a very clear sense of how to deal with this,” said Michael Shifter, president of the Inter-American Dialogue research center in Washington. “It means already limited resources will have to be devoted to dealing with this problem. They’re already stretched.”

Despite having one of the region’s largest economies, Brazil may also struggle. Shifter notes that Zika cases were found in one of the poorest regions of northeast Brazil, where the health systems are most fragile.

The CDC and Pan American Health Organization are working with countries to help them with laboratory testing to detect Zika. But the health organization does not advise delaying pregnancy in countries where access to birth control and information about its use are scarce.

“How are women supposed to follow a recommendation to delay pregnancy if they lack information and access to contraception?” Dr. Suzanne Serruya, director of the organization’s Latin American Center for Perinatology, Women and Reproductive Health, said in an e-mail. “And if contraception fails, what are they supposed to do if they become pregnant?”

In the new interim guidelines, the CDC told heath care providers in the United States to work closely with mothers to track down babies possibly suffering from the rapidly spreading virus.

Doctors and nurses were advised to test infants born to women with positive or inconclusive tests for the Zika virus as well as infants with microcephaly or those showing signs of brain calcification caused by the tropical disease.

Last week, CDC officials said pregnant women should consider postponing trips to 14 destinations, including Brazil, Colombia, El Salvador and Guatemala. On Tuesday, they added the U.S. Virgin Islands and Dominican Republic to the list.

Arkansas health officials confirmed Tuesday that a resident had tested positive for a “mild case” of the Zika virus after returning from a trip “out of the country.” It warned pregnant women in particular to consider postponing travel to Central and South America.

Arkansas authorities also issued guidelines that they hoped would prevent the spread of the disease, urging people traveling back to the state from countries with Zika outbreaks to avoid being bitten by mosquitoes for 10 days after their return. “Mosquitoes here in Arkansas can become infected with the virus if they bite someone who has Zika,” the Arkansas Department of Health warned.

“Travelers to areas where Zika is present should also go to their doctor if they experience any of the symptoms associated with Zika within three to seven days after they return,” Dr. Nate Smith, the health department’s director, said in a statement.

The health department advised returning travelers to use insect repellant with Deet, wear long-sleeved shirts and clear standing water from containers such as flowerpots as ways to avoid being bitten by mosquitoes.