|
 In an analysis of seven cases of children with joint deformities,
the researchers said the abnormalities - a condition known as
arthrogryposis - could be a result of Zika's effect on the
developing baby's motor neurons, cells that control the contraction
or relaxation of muscles.
In all the cases, the mother also had either documented Zika
infection, a Zika-like rash during pregnancy or had given birth to a
baby with an abnormally small head.
The Zika outbreak was first detected last year in Brazil, where it
has been linked to more than 1,700 cases of microcephaly, a birth
defect marked by small head size that can lead to severe
developmental problems in babies.
The mosquito-borne virus has moved rapidly through the Americas and
has recently begun spreading within the United States, where Aedes
aegypti mosquitoes thrive in the warm south.
Because this latest research, published in the British Medical
Journal (BMJ) on Tuesday, was an observational study looking back at
cases of arthrogryposis, it could not draw definitive conclusions on
whether Zika is a direct cause.
But the scientists, based in Recife - the Brazilian city at the
center of the Zika epidemic - said the condition might be related to
the way Zika affects the brain and the way motor neurons carry
signals to an unborn baby's muscles.
If the signals are weak or deficient in some way, this can lead to
fixed postures in the womb and consequently to deformities in a
baby's joints, said Vanessa van der Linden, a researcher at Recife's
Association for Assistance of Disabled Children, who led the study.
"We don't know for sure, but we think there's a problem with the
motor neurons ... and that the damage is probably because of the
virus," she said in a telephone interview. "We need to study more
cases to understand this better."
[to top of second column] |
All the children studied also showed signs of brain calcification, a
condition in which calcium builds up in the brain. Scientists think
Zika infection destroys brain cells and forms lesions similar to
scars on which calcium is deposited.
Scientists have now established a strong link between Zika and
microcephaly, but Jimmy Whitworth, a professor of International
Public Health at the London School of Hygiene & Tropical Medicine,
said these latest findings, alongside other studies, also reveal
more of Zika's harmful consequences.
"It is becoming increasingly clear that this virus can cause a wide
range of other abnormalities including visual and hearing defects
and brain damage in babies with normal sized heads," he said.
The finding that the affected babies all had patterns of peripheral
nerve damage, which had caused contracting of the joints, was
"consistent with our knowledge that Zika virus is particularly
damaging to nervous tissue", he said.
(Reporting by Kate Kelland; Editing by Janet Lawrence)
[© 2016 Thomson Reuters. All rights
reserved.] Copyright 2016 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
