There continues to be more and more information being published about Zika and the continued concerns over side effects of the viral infection. So there are several new key facts that every parent needs to know.
Based on more research the CDC and WHO have now confirmed the link between Zika virus infection and birth defects. Two interesting studies were just published further substantiating the link. The first was in the journal Stem Cell in which researchers found that the Zika virus selectively infects cells in the brain’s outer layer which makes “ those cells more likely to die and less likely to divide normally and make new brain cells.” In other words, Zika preferentially affects tissues in the brain and brain stem of the fetus. While this does not prove that Zika causes microcephaly it certainly points to the fact that brain cells are very susceptible to the virus and if the cells don’t divide to make new cells….one would think the brain would be smaller as would the head (microcephaly).
Another article in the New England Journal of Medicine reported on research that had been done on 88 pregnant women in Rio. The article stated, “infection during pregnancy has grave outcomes including fetal death, placental insufficiency, fetal growth restriction and central nervous system involvement.” They also stated that “major fetal abnormalities were found in nearly a third of the women who had been infected and had undergone ultrasounds.” This virus seems to act like some other viruses (rubella) that have caused congenital infections and brith defects as well. The study also showed that the Zika virus may affect the placenta as well, which could cause miscarriages and/or still births.
While much of the Zika virus news has focused on pregnant women and associated birth defects, countries with high rates of Zika infections have also seen an increase in the number of cases of Guillian Barre Syndrome (GBS), a neurological disorder which causes muscle weakness and varying degrees of paralysis. A study published in The Lancet reviewed results of blood tests from patients who had Zika and GBS in French Polynesia, which was the site of an earlier Zika outbreak. Of the 42 patients that had been diagnosed with GBS, 41 had antibodies to Zika, which is more evidence that Zika may be the cause of the serious neurological condition. While GBS has been seen in children and adolescents post Zika, it tends to be seen more frequently in older adults and is actually a bit more common in men.
Although it seems that the virus affects pregnant women and older adults in different ways, the severe side effects of Zika are in both cases related to the nervous system. There is still much research to be done to elucidate the how and the why, before any type of cure or vaccine is available, but all of these studies are getting scientists one step closer.
Another issue that scientists continue to work on is how to best test for Zika virus. It is still not clear how long the incubation period is after being exposed to Zika virus, and remember about 80% of people will not even realize they were infected. With that being said, one of the tests ( called a PCR test) requires that the patient’s blood be drawn within 4 - 7 days after being bitten by the infected mosquito. Another test ( Zika MAC-ELISA) , may be the better test as it may be used for a longer period of time after being bitten. Both of these tests are being used for diagnosis and are now being sent to qualified labs to help speed up the diagnosis of Zika.
In the meantime as warmer, humid weather is approaching the United States, we all need to be pro-active about using insect repellant, reduce standing water (it has been raining in TX for days), and wear long sleeved clothes and pants when possible. Stay tuned for further updates as the CDC expects to see cases of Zika in the U.S. over the coming months. To date all of the Zika cases that have been diagnosed in the U.S. have been imported and not acquired here.