A painful mosquito-borne disease is spotted in the Western Hemisphere for first time, boosting U.S. risk
Given a choice between dengue fever or another mosquito-borne disease called chikungunya fever, choose dengue every time. Neither has an available vaccine or treatment, but chikungunya (pronounced chik-un-GUHN-ya) is far more severe – it literally means “that which bends up” because patients are often stooped over from debilitating joint pain.
If you’re a resident of the Caribbean island of St. Martin (or lucky enough to be traveling there for the holidays) you are now at risk of both. The island, roughly the size of Manhattan and located some 300 kilometers east of Puerto Rico, has the first confirmed outbreak of chikungunya in the Western Hemisphere.
As of late last week there were 26 laboratory-confirmed cases of the disease on the island, with over 100 total cases suspected. Chikungunya has been found in both the French and Dutch parts of the island. It has also spread to the nearby island of Martinque, which has two laboratory-confirmed cases. And representatives of the U.S. Centers for Disease Control and Prevention (CDC) say that the virus could spread to other Caribbean islands and the surrounding mainland areas in the coming months or years. The outbreak in such a prime spot for tourism also heightens the risk of a future outbreak in the United States.
Disease experts are not sure how the virus got to St. Martin. The patients in St. Martin had not recently left the island, so presumably the virus was locally acquired. The top theory is that a traveler contracted the disease in another region of the world and was then bitten by a local mosquito in St. Martin that went on to infect other people. Another, less likely option is that an infected mosquito traveled to St. Martin, perhaps as a stowaway on a ship or plane. “We know the area has the right mosquitoes to potentially transmit chikungunya, so you could question, ‘why not before now’ or ‘why not a year from now,’” says Erin Staples, an arboviral diseases expert at the CDC. “This just happened to be the right combination of factors,” such as ongoing transmission in other areas and an unlucky bite.
All it takes to spread chikungunya is for a female mosquito to feed twice, first engorging herself on an infected person’s blood and then later biting someone else. But unlike dengue, which is already common in the region and is transmitted via the same Aedes aegypti and Aedes albopictus mosquitoes, locals do not have any immune protection for chikungunya since it’s new to the area—meaning it could spread quickly.