The Zika virus, the subject of one of our recent articles, is spreading throughout the hemisphere after crossing the Atlantic from Africa and Asia. At present, cases have been reported in every country except for Canada and Chile. News articles regarding the tragic consequences it has on pregnancies are published daily. The Center for Disease Control (CDC) has gone so far as to issue travel advisories warning pregnant women to stay away from countries with widespread outbreaks, like Brazil.
Interestingly, in Africa, Zika virus is thought to be a mild pest, causing minor illness; in fact, 80% of those infected have no symptoms at all. It is not associated with birth defects like microcephaly where it is traditionally found. It has been shown to occasionally cause a rare nerve disorder called “Guillain-Barre Syndrome”, which presents with muscle weakness leading to possible paralysis. Some recover fully, but many have long-term issues and 5% die from respiratory arrest and other complications. This is not, by the way, a disease related to pregnancy.
Yet, this virus is now becoming an issue that some predict may affect up to 100,000 newborns. It isn’t hard to imagine that this will tax the resources of poor countries that are dealing with it.Why is a virus that isn’t a big problem in its original territory suddenly causing these heartbreaking deformities? Zika is an equatorial disease spread by mosquitoes, conditions that are present in both Brazil and Africa. Why should it have so different a presentation in one part of the world than another?
It is my opinion that we dealing with a viral “mutation”. Viruses are well-known for their ability to change genetically. These changes, or mutations, may either be insignificant or have major consequences. Luckily, most are the former, and this is the reason why influenza vaccines work to prevent illness. This year’s flu is usually similar to last year’s, and flu vaccines are made from components of last year’s virus. If an influenza virus mutates significantly, it usually causes many more cases and, often, deaths as we have less immunity to it.
Imagine if Ebola, which caused a regional epidemic in West Africa in 2014, had mutated to become easily transmissible through the air? It would have been more challenging to control and could have reached pandemic status.
Despite this, I can find nothing in the news that mentions the possibility that the virus has mutated. If we are to have success in producing treatment or prevention of this viral illness (none exists at present), we will have to take into account the chance that this Zika virus is not the same as the original.
Joe Alton, MD