Breakbone Fevers - Stuff I Didn't Know

When it comes to virology I’m pretty ignorant. I was reading an article in the NYT Science section today about an outbreak of Chikungunya virus in India. Now I do know what Chikungunya is just like I know what O’nyong ‘nyong and Dengue Fever are. Maybe I was asleep when we discussed those diseases at the London School of Hygiene and Tropical Medicine or maybe it wasn’t known then (it was over 30 yrs ago) but I thought all three diseases were the same. It turns out they all arboviruses (transmitted by insects) and the symptoms of the diseases are very similar, but they are not the same viruses

Chikungunya is caused by infection with an Alphavirus (positive sense, single-stranded RNA virus) and is transmitted by the bite of certain Culicine mosquitoes, usually Aedes aegypti.

O’nyong ‘nyong is a closely related virus of the same genus but is transmitted by the bite of an Anopheline mosquito.

Dengue Fever is caused by infection with a Flavivirus (also a positive sense, single-stranded RNA virus) but is also transmitted by the bite of Culicine mosquitoes, usually Aedes aegypti.

All of these viral infections cause such severe pain that they are often described as ‘breakbone fevers’. Dengue fever can be transmitted in the USA but only in warm climates. Aedes mosquitoes don't like cool weather. Also, there is no direct person-to-person transmission of these viruses.