London News & Search
London researchers a have found a new tool that may help doctors quickly screen which people have been exposed months earlier to the Zika virus, school officials said this week.
While doctors can now test whether people have the virus by collecting and testing blood and urine samples, scientists at Western University have come up with a way to use saliva to determine if a person has been exposed to the Zika virus, which has spread through Africa and Central and South America.
Those scientists hope they can take promising results in the lab to create a device that can be brought to affected areas to quickly screen people.
“We need to have better, rapid, and cost effective diagnostic test for screening,” said Eric Arts, PhD, chair and professor of the Department of Microbiology and Immunology at Western’s Schulich School of Medicine & Dentistry. He co-authored a study that pinpointed the specific protein signature for Zika that is present in saliva.
“Three months after the babies were born, we collected saliva from the mother and the babies, and the Zika virus peptides were present in the saliva of all three,” said Dr. Walter Siqueira, a dental clinician-scientist and associate professor from Schulich.
The current diagnostic test used by the U.S.-based Centers for Disease Control and Prevention uses blood tests to look for changes to RNA. The drawback to this method is that it is able to detect the virus only up to one week after exposure. Since proteins in saliva are more stable than RNA, saliva can be tested to detect the virus far longer after exposure than with the traditional method.
“Our paper opened the window of detection to more than 20 days, and in this particular case, nine months after exposure,” said Dr. Siqueira.
The study, published online Tuesday in the Journal of Dental Research, also showed mutations in the amino acid sequence that were different for each twin, suggesting that these mutations may play a role in whether or not a baby will develop microcephaly, a birth defect in which a baby’s head is smaller than expected when compared to babies of the same sex and age.
Zika virus infection during pregnancy is a cause of microcephaly. During pregnancy, a baby’s head grows because the baby’s brain grows. Microcephaly can occur because a baby’s brain has not developed properly during pregnancy or has stopped growing after birth.
Congenital Zika syndrome is a unique pattern of birth defects found among fetuses and babies infected with Zika virus during pregnancy. Congenital Zika syndrome is described by the following five features:
• Severe microcephaly where the skull has partially collapsed
• Decreased brain tissue with a specific pattern of brain damage
• Damage (i.e., scarring, pigment changes) to the back of the eye
• Joints with limited range of motion, such as clubfoot
• Too much muscle tone restricting body movement soon after birth
Zika is spread mostly by the bite of an infected Aedes species mosquito. These mosquitoes bite during the day and night. The virus can be passed from a pregnant woman to her fetus and cause birth defects.
There is no vaccine or medicine for Zika.
Local mosquito-borne Zika virus transmission has been reported in parts of Texas and Florida but not in Canada.
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