ZIKA VIRUS ALERT: Pregnant
women are urged to stay away from regions affected by the Zika virus outbreak
due to the risk of brain damage to foetuses.
The World Health Organisation has declared the Zika virus an
international public health emergency, prompted by growing concern that it
could cause birth defects. Until recently, global health officials paid
little attention to the Zika virus that circulated in the same regions as
Dengue and Chikungunya viruses. It is estimated that four million people
could be infected by the end of the year. Pregnant women have been urged not to
travel to about 24 countries, mostly in the Caribbean and Latin America, where the
outbreak is growing. Zika infection appears to be linked to the
development of unusually small heads and brain damage in newborns.
What is the Zika virus?
The Zika virus is a
mosquito-transmitted infection related to dengue, yellow fever and West Nile
virus. Although it was discovered in the Zika forest in Uganda in 1947 and is
common in Africa and Asia, it did not begin spreading widely in the Western
Hemisphere until last May, when an outbreak occurred in Brazil.
Until
now, almost no one has had major infections from Zika. Few have had
immune defenses against the virus, so it is spreading rapidly. Millions of
people in tropical regions of the Americas may have been
infected. Scientific concern is focused on women who become infected while
pregnant and those who develop a temporary form of paralysis after exposure to
the Zika virus.
How is the virus spread?
Zika
is spread by mosquitoes of the Aedes genus, which can breed in a tiny pool of
water and usually bite during the day. The aggressive yellow fever mosquito,
Aedes aegypti, has spread most Zika cases. The mosquito is found in Nigeria and
some other countries.
What is the danger?
Zika
causes brain damage in infants. Experts aren’t certain how it happens, or even
whether the virus is to blame. The possibility that the Zika virus causes
microcephaly – unusually small heads and damaged brains – emerged only in
October 2015, when doctors in northern Brazil noticed a surge in babies with
the condition.
What is microcephaly?
Babies
with microcephaly have unusually small heads. In roughly 15 percent of cases, a
small head is just a small head, and there is no effect on the infant,
according to experts.
But
in the remainder of cases, the infant’s brain may not have developed properly
during pregnancy or may have stopped growing in the first years of life. These
children may experience a range of problems, like developmental delays,
intellectual deficits or hearing loss.
What countries are affected?
Pregnant
women are urged to avoid about 24 destinations mostly in the Caribbean, Central
America and South America.
Symptoms
It’s
often a silent infection, and hard to diagnose. Until recently, Zika was not
considered a major threat because its symptoms are relatively mild. Only one of
five people infected with the virus develop symptoms, which can include fever,
rash, joint pain and red eyes. Those infected usually do not have to be
hospitalized.
What are the tests?
There
is no widely available test for Zika infection. Because it is closely related
to dengue and yellow fever, it may cross-react with antibody tests for those
viruses. To detect Zika, a blood or tissue sample from the first week in
the infection must be sent to an advanced laboratory so the virus can be
detected through sophisticated molecular testing. The Centres for Diseases
Control and prevention, CDC, testing algorithm for pregnant women who have
visited countries in which the Zika virus is spreading.
Most
of those who get the virus do not feel ill — and there is no evidence that
babies are hurt only when the mother has been visibly ill. But at the time
the guidelines were issued, the CDC and state health departments simply did not
have the laboratory capacity to test every pregnant woman who visited Latin
America and the Caribbean in the last nine months, as well as every pregnant
woman in Puerto Rico.