This week we’re looking at all things Zika and addressing someone of the questions you guys had to ask. From ‘where did this virus come from all of a sudden?’ to ‘should we move the Rio Olympics?’, we’ll be answering the big question: what exactly is Zika?
The Zika virus was christened after scientists first isolated the virus in rhesus monkeys found in the Zika forest. This occurred back in 1947 and, since then, remained a rather insignificant virus for many years, only being identified in a human for the first time in 1964 who experienced a mild, non-itchy rash. However, the virus has gone from a mild nuisance to an epidemic and we’re not quite sure why; some scientists claim the over-use of pesticides, while some blame global warming; most agree however, that the boom is linked to increased levels of mosquito vectors who spread the disease.
Despite the media hype and hysteria, Zika virus is relatively harmless to those it infects. Mild fevers, light rashes, and maybe some conjunctivitis if you’re really unlucky will last little up to a week; while treatment simply consists of rest and plenty of fluids, similar to a regular, run of the mill, common cold. So why is it that we’re all up in arms about Zika?
You may have seen pictures of babies with abnormally small heads. Microcephaly, as it’s called, is a birth defect that’s becoming more prolific - and you guessed it, it’s linked to the Zika virus. While Zika poses an arguable at best threat to those of us who are already up and walking about, it poses a more serious threat to our unborn population, putting them at great risk of neurological defects. But we don’t want to show all our cards on the first day, so we’ll be looking into Microcephaly a bit further tomorrow.
To combat your enemy, you must first know your enemy. That’s why Zika virus has been in the eyes of many research virologists over the past couple of years who have done all they can to learn the basics about this virus. The virus itself belongs to a group of viruses called Flaviviruses, which include other known viruses such as Yellow Fever and the West Nile viruses. The shell of the virus shares characteristics with a number of viruses; this ‘Icosahedral shell’ is what mathematicians call a polyhedron – basically, it’s 20 triangles put together in a way that it almost looks spherical.
This shell is robust, and it needs to be as it houses the most important part of the virus – the RNA. RNA is very similar to DNA and carries out many of the same roles: namely, it holds the genetic material of the virus which allows it to replicate.
When we talk about biology, viruses are right down there at the bottom when we talk about complex forms of life, to the extent where no one is quite sure if a virus is truly actually ‘alive’. Because a virus is so simplistic, they cannot replicate on their own. Instead, they must find a way into a cell of the organism they have infected and steal the complex molecules which they themselves lack in order to multiply. Once inside a human cell, the RNA makes hundreds of thousands of copies of itself using these stolen human components. As soon as the copying process is completed, the replicated RNAs further subvert human cells for their own use and recreate icosahedral shells around each RNA copy.
This leaves the question of how the virus gets inside a cell to replicate in the first place. When a virus is finished replicating, it moves to the edge of the cell. It then pushes its way out through the membrane in such a way that some breaks off and wraps itself around the virus as it leaves – this is what allows the virus to infect other cells.
The virus, wrapped in this human cell membrane, travels to another nearby cell. Once it reaches the target, the membrane it stole from the previous cell joins onto the membrane of this new target. Incidentally during this process, the new target cell engulfs the virus inside this membrane, this allows the virus to once again begin its replication cycle and eventually make you feel ill