While fears continue to mount about the spread of the Zika virus, scientists are scrambling to verify a link between the illness and a rise in birth defects in Brazil.
There are at least six studies underway in the Latin American country looking at the possible connection between the virus and microcephaly, a condition where infants have abnormally small heads.
In November of last year, a Brazilian investigation found an average 20-fold increase in the incidence of the condition among newborns in areas where the virus was known to be prevalent.
In total, the South American nation has some 4,000 cases of microcephaly.
Dr. Darcy Fehlings, senior clinician scientist at Toronto's Holland Bloorview Kids Rehabilitation Hospital, told Â鶹´«Ã½ that the outbreak needs to be taken "seriously."
"It is concerning and deserves a lot of attention," said Fehlings.
"It is a rare presentation in pediatrics given that it is grouped together and the prevalence is high," she added.
The Zika virus, which is spread by mosquitoes, has been native to parts of Africa and Asia for years, but was found in Brazil last May.
It is typically considered a mild illness that leaves sufferers with symptoms such as a fever, rash, red eyes and joint pain for several days to a week.
Health authorities around the world have treated this new link to microcephaly with extreme caution. Many, including Public Health Agency of Canada, have recommended that women travelling to regions affected by the Zika virus should meet with their doctor and consider postponing their plans.
Meanwhile officials in El Salvador, Colombia and Brazil have suggested that women should stop getting pregnant altogether until the crisis has passed.
While the World Health Organization declared a global emergency over the explosive spread of the virus earlier this week, it has stressed that the connection to microcephaly is circumstantial and has not yet been proven scientifically.
"We must remember that we don't know either if Zika does cause microcephaly," said WHO spokesman Gregory Hartl.
Part of the caution is due to the fact that there are already many established genetic and developmental causes for the condition, including:
- Caniosynostosis – or a premature fusing of the joints in the bony plates that make up an infant's skull.
- Chromosomal abnormalities, such as Down syndrome.
- Reduced oxygen supply to the brain during pregnancy.
- Exposure to drugs, alcohol or other toxic chemical in the womb
- Uncontrolled phenylketonuria in the mother, meaning her body cannot break down on the amino acids found in proteins.
In Brazil, a combination of these factors could be at play.
Dr. Kym Boycott, clinical geneticist, at Ottawa's Children's Hospital of Eastern Ontario, says if the virus is found to be responsible for the rise of microcephaly it will pose many new questions about its effects.
"If this virus is shown to actually be the cause, how does it affect brain development? What is it doing to cause those brain cells to not form properly, and not to be the same in a number of children not exposed to the virus," she said.
's two daughters, Claire, 14, and Lola, 9, were . Despite their disabilities, which include seizures, dwarfism, difficulty eating and muscle stiffness, Hartley says her daughters are "beautiful" and she is "grateful to be their mom."
"I love my girls and I love what they have done in their lives, and how they have changed mine," she said from her home near Wichita, Kansas.
Hartley also encouraged mothers who have given birth to children with microcephaly to keep an open mind about the kind of life they can live.
"To me they're all beautiful and they all have something very special to offer this world," she said.
"I want them to just understand that they aren't going to be sure about what their child will be like until their child shows them."
With a report from Â鶹´«Ã½' Medical Correspondent Avis Favaro and producer Elizabeth St. Philip
