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Sri Lanka: One Island Two Nations
A Brief Colonial History Of Ceylon(SriLanka)
Sri Lanka: One Island Two Nations
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?????????????????????????????????????????????????Thursday, October 27, 2016
Scientists are bewildered by Zika’s path across Latin America
Tatiane
holds her nephew Arthur Conceicao, who was born last year with
microcephaly, during his birthday party in Recife, Pernambuco state,
Brazil. (AP Photo/Felipe Dana) (Felipe Dana/AP)-Lucas
Matheus, who was born with microcephaly, during his physical therapy
session at the UPAE hospital in Caruaru, Pernambuco state, Brazil. (AP
Photo/Felipe Dana) (Felipe Dana/AP)
By Dom Phillips and Nick Miroff October 25 at 3:24 PM
RIO DE JANEIRO — Nearly nine months after
Zika was declared a global health emergency, the virus has infected at
least 650,000 people in Latin America and the Caribbean, including tens
of thousands of expectant mothers.
But to the great bewilderment of scientists, the epidemic has not
produced the wave of fetal deformities so widely feared when the images
of misshapen infants first emerged from Brazil.
Instead, Zika has left a puzzling and distinctly uneven pattern of damage across the Americas. According to the latest U.N. figures,
of the 2,175 babies born in the past year with undersize heads or other
congenital neurological damage linked to Zika, more than 75 percent
have been clustered in a single region: northeastern Brazil.
The pattern is so confounding that health officials and scientists have
turned their attention back to northeastern Brazil to understand why
Zika’s toll has been so much heavier there. They suspect other,
underlying causes may be to blame, such as the presence of another
mosquito-borne virus like chikungunya or dengue. Or that environmental,
genetic or immunological factors combined with Zika to put mothers in
the area at greater risk.
“We don’t believe that Zika is the only cause,” Fatima Marinho, director
of the non-communicable disease department at Brazil’s Ministry of
Health, said in an interview.
Brazilian officials were bracing for a flood of fetal deformities as
Zika spread this year to other regions of the country, Marinho said.
However, “we are not seeing a big increase.”
Researchers and health officials remain cautious about the
lower-than-expected numbers. The latest studies have found more evidence
than ever that the virus can inflict severe damage on the developing
infant brain, some of which may not be evident until later in childhood.
But researchers so far have learned a lot more about Zika’s potential to do harm than its likelihood of doing so.
Scientists at the U.S. Centers for Disease Control and Prevention are
closely watching Puerto Rico, which has reported more than 26,800 cases
of Zika. More than 7,000 pregnant women could be infected by the end of the year, according to the CDC.
But although the outbreak has spread this year to more than 50 nations
and territories across the Western Hemisphere, U.N. data shows just 142
cases of congenital birth defects linked to Zika so far outside Brazil.
In Colombia, a country praised for some of the most rigorous standards for
detecting and monitoring Zika, the government has tallied more than
104,000 Zika cases, including nearly 20,000 pregnant women. It has the
second-highest number of Zika infections in the world after Brazil.
But so far, Colombia has had just 46 babies born with
congenital nervous system damage linked to Zika. And the number of new
Zika cases in Colombia has fallen so sharply that the government in July
declared the epidemic over, saying the virus will remain a threat but no longer spread rampantly.
Colombia is investigating 332 more cases of birth defects for a possible
Zika link, but health officials there had been prepared for many more.
“Our focus on Zika has changed,” said Ernesto Marques, an epidemiologist
at the University of Pittsburgh who is working on a project to develop a
vaccine for the virus.
Marques is from Recife, the city in northern Brazil hardest-hit by the
Zika outbreak, and he was part of the team that first identified the
virus as a possible culprit when deformed infants began showing up
“almost every day” in Recife’s maternity wards at this time last year.
At the time, Marques said scientists were focused on identifying Zika as
a “causal agent” for the sudden increase in birth defects, especially
microcephaly, in which babies are born with undersize heads and often
calcified brain tissue.
“Now we’ve settled on Zika as the smoking gun, but we don’t know who
pulled the trigger,” said Marques, speaking from Recife, where he is
working with government researchers.
One of the leading theories, said Marques, is that northeastern Brazil’s
last dengue outbreak was in 2003 — relatively long ago — so perhaps
mothers in the area had relatively fewer antibodies to cope with Zika,
which is spread by the same mosquito.
“Sexual habits and hygiene may also play a role,” he said, explaining
that researchers are looking at whether sexual transmission can infect
the uterus and placenta with the virus, potentially exposing the fetus
to elevated risk.
“We suspect the villain has an accomplice, but we don’t know who it is,” Marques said.
Many question marks
Researchers caution that it will take years to fully identify the
dangers Zika poses to babies’ brains, and microcephaly is just one
threat from the virus. A Zika infection poses the greatest danger toward
the end of the mother’s first trimester of pregnancy, and its harmful
effects on fetal development may not be apparent at birth or manifest
themselves until later in childhood.
Marcos Espinal, the director of communicable diseases and health
analysis at the Pan American Health Organization, said U.N. health
officials were right to put the world on high alert earlier this year
because so little was known about Zika.
“If you don’t know about something, you better take preventative
measures to minimize the risks,” Espinal said. “So maybe the fact that
we don’t have a lot of microcephaly means that we were doing our jobs”
and helped women avoid infection.
At the peak of Zika alarm earlier this year, several Latin American
countries urged women to delay pregnancy. El Salvador’s government
recommended waiting two years. The widespread anxieties produced by the
outbreak may have led to an increase in abortions in Latin America, a
region where the procedure is widely banned. Anecdotal evidence suggests
more women have been quietly terminating pregnancies over worries that
their babies might be deformed.
This may also help explain the relatively low number of babies born with Zika-related birth defects outside northeast Brazil.
“It is very difficult to work out truly what is going on,” said Oliver
Brady, an epidemiologist at the London School of Hygiene and Tropical
Medicine who has been working with the Brazilian government on Zika.
Until last year, Brazil reported about 150 cases annually of
microcephaly, a condition that can also be caused by diseases like
herpes and syphilis. Claudio Maierovitch, a former senior Brazilian
health official responsible for monitoring Zika when the epidemic
started, said the figure was probably an undercount, and around 500
cases of microcephaly a year pre-Zika would be a more accurate number.
When the microcephaly outbreak was first identified in Brazil, spooked
health officials erred in the other direction and overdiagnosed the
condition. Eventually, nearly 5,000 newborns that had been diagnosed
with possible microcephaly turned out to be fine, according to Marinho,
the Brazilian health official.
But that still leaves at least 2,000 instances of Zika-related birth
defects in the country, with an additional 3,000 cases under
investigation.
A big problem in determining whether Brazil has a higher rate of
Zika-related birth defects is that no one is sure how many people caught
the virus in 2015, when it was little known and widely confused with
dengue.
“The fact is we don’t have any idea how many cases there were,” said
Maierovitch, meaning it’s possible Brazil’s birth-defect totals could
simply be a reflection of a Zika outbreak that was far more pervasive
than anywhere else.
An eye on U.S. territory
Puerto Rico is the next laboratory for understanding Zika. CDC
researchers are watching for Zika-related birth defects on the island,
but the mainland United States appears to have averted a major outbreak
so far.
The vast majority of cases the CDC has counted were attributed to infections acquired abroad or through sexual transmission, though mosquitoes have spread the virus in
a few neighborhoods in and around Miami. Experts have warned, however,
that local mosquito-driven outbreaks may be occurring in other parts of
the country, particularly in states along the Gulf of Mexico. An
estimated 80 percent of people infected with the virus don’t have
symptoms and don’t realize they have Zika.
Peter Hotez, dean of the National School of Tropical Medicine at Baylor
College of Medicine, said Congress’s failure to approve Zika funding
this year means there was no effective way to accurately count how many
people were infected.
“We’ll have to hold our breath to see what happens in labor and delivery
suites in a few months,” he said. “That’s the only way we’ll know
whether we’ve dodged a bullet.”