Like HowStuffWorks on Facebook!

How Giant Viruses Work


The Target Audiences of Giant Viruses

I know that stomach bug you had recently seemed like the end of the world. In fact, the only good thing that came out of it was probably a modest weight loss! So if that's a teensy-weensy baby virus when compared with a Pandoravirus, it's safe to assume that we're all doomed, right? Breathe a sigh of relief, my friends, for that is probably not the case.

"The majority of these giant viruses have been shown to infect amoeba," Wilhelm explains. Amoeba are a far cry from human beings, since they are microscopic, single-celled organisms that primarily reside in water [source: New World Encyclopedia]. Wilhelm also notes that single-cell algae and protozoan grazers are other typical targets of giant viruses, but insists that the danger to humans is minimal, if present at all. "We have no real evidence that these viruses do anything to humans or animals," he says.

If giant viruses are no harm to humans, then what's the big deal? As it turns out, some of them have the potential to inadvertently affect people through ecologic and economic avenues. For example, Wilhelm and his team have spent years studyingAureococcus anophagefferens virus (AaV), which is unwittingly hosted by algae of the same name (the virus is usually named after the algae). The affected algae are believed to play a role in the growth of "brown tide blooms" on the East Coast of the United States, although it has spread to other areas now.

Springtime blooms of AaV present a major problem to coastal areas, such as Long Island's Great South Bay, because they take over the area, preventing the growth of sea grass. As a result, there has been a huge decline in shellfish and other marine life, negatively impacting the appearance, functionality and economic potential for many affected areas [source: Columbia University].

Figuring the virus out since it first appeared in the 1980s has been a lengthy process, however. "In 2014 we completed the genomic sequence and were surprised that it fit into this giant virus category," says Wilhelm of the virus, which boasts 370,000 base pairs. It also presented some unforeseen surprises. "Not only does it have genes that are similar to other giant viruses, it also has genes similar to the host, to bacterial genes, to bacterial virus genes," he says. "It's a real mosaic genetically."

Still, some scientists appear to be poking a sleeping bear by unearthing viruses from long ago. Are they putting us in harm's way, however inadvertently?