
Advertisement
Advertisement

Dr. Tim Brooks: Chikungunya is a disease that’s pretty much had its day, but it comes around every so often. Its name translates to “that which bends up,” because the biggest problem with the disease is the arthritic debilitation that follows the infection. It’s also got a fascinating history: Chikungunya was first pinned down in Tanzania in 1952, but historical accounts appear across Asia and Africa as early as 1779. Historically, outbreaks began in the Indian Ocean Basin, and it’s been able to travel very successfully since then.What are the symptoms exactly?
Normally chikungunya presents with joint pains, a rash, and acute fever, followed by all the other symptoms you associate with high fever: headache, diarrhea, back pain. The main problem is the arthritic pain, which does not go away for maybe 10% of patients. It can persist for up to three years, and is very debilitating. It tends to affect the smaller joints, causing local swelling and pain. Once you’ve got it, you’ve got a lifelong immunity to it, but it will generally infect a large portion of the population, move on, and then disappear until the next generation comes up.
Advertisement
Chikungunya survives in closely connected landmasses, but it’s also possible for someone who travels with it to spread the disease during the incubation period, when mosquitoes in a new territory bite them and contract the disease. We’ve seen this in the last major epidemic, which was in 2007. That was really fascinating. The virus spread way beyond where it’d ever gone before, and most importantly, it had a single base mutation, where one nucleic acid changed.

Well, it certainly increased the virus’s virulence, and cases became more severe. But it also altered its mosquito tropism. Instead of being confined to be spread only by the yellow fever mosquito, the virus evolved to use the tiger mosquito as a secondary vector. This mosquito is from Southeast Asia, and it’s a very tough little bug. It’s famous for traveling around the world in motorcar tires.Wait, what? These mosquitos breed in tires?
[Laughs] Yes, motorcar tires shipped worldwide often have water in them, and the mosquitoes can live and breed in that water, and then establish themselves around the world.So exactly how virulent is this disease?
Chikungunya has an extremely high attack rate in a vulnerable population. Up to 50% of people susceptible to the disease get it, and it has a very high rate of epidemic. The problem is that many countries that are currently experiencing cases don’t have the ability to properly handle it. If you look at the number of suspected cases in parts of the Caribbean, there are reports of 1000 cases, but only 1400 confirmed cases. Part of that is that they don't have the resources to identify it.How bad do you think it could get in the southern United States?
Well, it could start in the south with a single tourist. Then, imagine a school kid comes into school with the disease. You might have some cases in that area, and whether or not the disease will spread depends on public health. If you cut back the number of mosquitos, you can cut back the potential for an epidemic. But many people in the rural areas of the south don’t necessarily have access to hospitals, or even health care. It’s those areas that I’m concerned about.
