Star

The San Juan Daily Star
Monday, March 21, 2016 27
HEALTH
1% Chance of Microcephaly in Zika Outbreak, Scientists Estimate
Study suggests relatively low risk of birth
defect but big numbers as virus spreads.
by Beth Mole
Based on data from a past Zika outbreak, researchers estimate
that there’s a one-in-100 chance that women infected
during the first trimester will give birth to a baby
with microcephaly—a birth defect that leaves infants with
small and malformed brains and skulls.
There’s still not a definitive link between microcephaly and
the mosquito-borne virus, which is currently blazing through
Central and South America. But the data coming in has only
strengthened the connection. For instance, a recent study
found that Zika virus can kill off developing brain cells.
With the new estimate on the rate of microcephaly in Zika
infections from an outbreak in French Polynesia starting in
2013, researchers are relieved that it appears the birth defect
is relatively rare.
“It means you have a 99 percent chance of having a normal
baby,” Dr. Laura Rodrigues, a professor of infectious disease
epidemiology at the London School of Hygiene & Tropical Medicine,
told The New York Times.
By contrast, birth defects from other in utero viral infections
can have far steeper risks. Pregnant women infected
with the rubella virus, for example, have at least a 38 percent
chance of having a baby with congenital rubella syndrome,
which can lead to heart disease, developmental delays, and
hearing loss.
To come up with an estimate for Zika, researchers sifted
through medical records from the outbreak of Zika in French
Polynesia between 2013 and 2015, which sickened 66 percent
of the 270,000 residents. The researchers also established the
baseline of microcephaly in the population, which was two cases
in 10,000 births. During the outbreak, there were eight total
cases, the researchers reported recently in The Lancet.
While the rate is relatively low, health experts are not sure
if it would be the same in different populations. Even if it is,
the virus is still spreading to millions throughout the dozens
of countries.
“If you apply a one percent risk to a large number of women,
it’s still a large public health problem,” said Simon Cauchemez,
the study’s lead author and the director of mathematical
modeling for the infectious diseases unit at the Pasteur
Institute in Paris.
Women Who Brought Zika Fears Home With Them
By LAURA BEIL
In December, Ami Levy and her husband, Jason, left frigid
Washington, D.C., for a two-week vacation in Argentina.
Once there, they headed north to the Brazilian
border for a couple of days, lured by Igauzu Falls.
She recalls the excitement when their phones’ GPS indicated
they finally were in Brazil, and the awe-inspiring
walls of water, some more than 24 stories tall.
And, she remembers, everywhere there were mosquitoes,
leaving bites on her thigh.
Back home the first week of January, Ms. Levy learned
she was four weeks pregnant.
Her first pregnancy had ended in miscarriage in September,
so it was with some hesitation that she left for another
trip, this time to Puerto Rico for a rendezvous with her
aunt and sister.
As soon as she arrived, local news broadcasts began
warning pregnant women about the dangers of infection
with the Zika virus, carried by mosquitoes and suspected
of causing devastating birth defects in infants born to infected
women.
She booked the first available flight home.
“I was on the beach for a few hours and didn’t put on
any bug spray,” said Ms. Levy, a 35-year-old psychotherapist.
“I had two bites when I got home Sunday.”
“I think I would have been more panicky if I hadn’t told
myself I needed to keep it together for my baby.”
The Zika virus is not yet known to be circulating in the
continental United States. But already, fear of the infection
has come home for many pregnant women and their families
who journeyed abroad before the risks were known.
The Centers for Disease Control and Prevention recently
reported that nine pregnant women were known to have
become infected while traveling. Yet many more are coping
with the possibility of exposure, reaching out to their doctors
for blood tests and ultrasounds, obsessing on news coverage
and trying to manage their worry.
The C.D.C. recommends that pregnant women receive
blood tests two to 12 weeks after travel to an affected area
to detect whether they may have been infected with the
Zika virus.
Those who may have been exposed are urged to consider
having extra ultrasounds to look for birth defects in the
developing fetus.
Nothing is guaranteed; the antibody test has its limits.
Ultrasounds often do not detect fetal microcephaly, the disease
causing misshapen heads and brain damage that has
been linked to infection with the virus.
According to the C.D.C., the scans are most accurate at
the end of the second trimester or early in the third.
“The risk is small, but the effects are tragic,” said Craig
Forest, 37, an associate professor of bioengineering at Georgia
Tech in Atlanta.
He and his wife, Roxanne, 32, spent Christmas vacation
in Costa Rica just as she was entering her second trimester
of pregnancy.
They chose that destination because of all the countries
in the region, it seemed to offer the safest environment for
a pregnant woman.
After 10 days of rain forest hikes and lazy sunsets on the
beach, Ms. Forest was covered with insect bites.
Back home in January, the couple began hearing news
reports about the Zika virus. Costa Rica was not mentioned.
“I’m looking at the list and thinking, ‘That’s all of Costa
Rica’s neighbors; we dodged a bullet on that one,’ ” Mr.
Forest said.
On Feb. 1, Costa Rica was added to the list of countries
in which Zika is circulating. The virus had been in the
country since at least December.
Ms. Forest’s doctor did not order a blood test for the infection,
because she had not had any symptoms. Her most
recent ultrasound appeared normal, and the couple say
they will ask for another at the cutoff time for an abortion.
They have lain in bed at night discussing the possibility,
something that would have been unthinkable a couple of
months ago.
They know the risks are remote — first that she might
have been bitten by an infected mosquito, and second that
the infection might lead to a birth defect.
“As analytically minded people, we’re trying to calculate
the odds,” said Ms. Forest, who is also an engineer.
But when they try to figure the likelihood of a birth defect
related to the Zika virus, all they can come up with is
“not zero.”
There is nothing to do but wait. “I actually tried to stop
reading the news,” Ms. Forest said.
Even when a pregnant woman is found to have been
infected, tests of blood or amniotic fluid cannot definitively
tell if the fetus was affected, said Dr. W. Ian Lipkin, an expert
in infectious diseases at Columbia University’s Mailman
School of Public Health, who is working to develop a
more reliable alternative.
Microcephaly seems to be a relatively rare complication.
But it’s also possible that the virus may cause “more subtle
damage that we can’t yet appreciate,” Dr. Lipkin said.
Sydney Silverstein, 35, an Emory University doctoral
candidate, has been living in Iquitos, Peru, since July. She is
eight and a half months pregnant.
There is no widespread epidemic of Zika virus in Peru,
but the virus is present in Lima. Moreover, she spent time
on the Brazilian border in late fall, early in her pregnancy.
She has had extra ultrasound scans from her doctor, and
her fetus looks unaffected.