Doctor Tyler Kokjohns write up on the Zika Virus.. you know to terrify you about the next major plague..
The Travels of Zika Virus
Not long ago Zika virus was an obscure mosquito-borne pathogen with a relatively restricted geographic distribution. Once causing comparatively few human infections in a few places, Zika virus has suddenly produced a global pandemic. An outbreak that began last May in Brazil may now have involved over a million persons (http://www.nytimes.com/2016/01/16/health/zika-virus-cdc-pregnant-women-travel-warning.html).
Zika fever is similar to the disease produced by dengue viruses with symptoms including rash, fever, headache and joint pain although up to 80% of Zika virus infections may produce no signs or symptoms of illness. However, the explosive Zika virus outbreak in Brazil captured world-wide attention because it is so closely correlated with an equally sudden and massive surge in children born with microcephaly. Mounting evidence strongly implicates Zika virus infections during pregnancy as the cause of this birth defect and led the U. S. Centers for Disease Control and Prevention (CDC) to issue an advisory for persons considering travel to regions experiencing outbreaks of this virus (http://www.cdc.gov/zika/pregnancy/index.html).
Zika virus is an arthropod-borne (arbo) virus transmitted primarily by mosquitoes so you don’t catch it from someone directly like you do with the flu. Unfortunately, it will not be possible to stop the global spread of Zika virus by screening airline passengers because many infected travelers will not exhibit signs or symptoms of disease as they transit borders. Travelers arriving with Zika virus in their blood may infect mosquitoes and seed outbreaks in new areas. Public health authorities in the U.S. hope any locally transmitted disease due to Zika virus follows the same pattern as dengue and produces comparatively small outbreaks of restricted geographic range. However, knowledge concerning potential mosquito vectors and alternate reservoir hosts for Zika virus is sketchy at this time, so we will have to wait to see how things actually play out.
No specific anti-viral treatments to halt Zika virus disease are available, there are no vaccines to prevent infections and the viruses cannot be intercepted at the border. That means control of Zika virus disease depends entirely on breaking the chain of mosquito transmission to and from humans. Because vaccines have been produced for the closely related viruses yellow fever and dengue, some authorities are optimistic similar products will be created to prevent Zika virus infections. However, any vaccines are years away and for now the best method of protection where Zika virus is circulating is to take precautions to prevent mosquito bites or avoiding those areas entirely. This situation may encourage the adoption of new control methods such releasing large numbers of genetically modified mosquitoes to disrupt the reproduction of disease-carrying populations or unleashing gene drives to push targeted vector species to extinction.
Zika virus is a member of an extended family of mosquito-borne viruses including dengue, chikungunya and West Nile virus whose geographic ranges are expanding. Location changes with spectacular consequences are nothing new for this virus group. Probably brought to the New World by the slave trade, yellow fever virus literally changed the course of human history. With an estimated 50 million cases producing over 20,000 deaths each year, dengue viruses take a huge toll on human health (http://www.who.int/csr/disease/dengue/impact/en/). The quick spread of a succession of viruses to new areas today is probably due to several factors including trade globalization, changes in human activities and increased air travel. Zika virus is threatening because a large proportion of the world’s population has no resistance to it. Zika virus may have been introduced to Brazil during the 2014 soccer World Cup competition and it is clear it has been transferred to several new countries since then by travelers. If the current Zika epidemic persists, the 2016 Summer Olympics in Rio de Janeiro may provide more opportunities for this virus to hitch rides to new locations.