Chikungunya is a mosquito-borne virus. (CDC)

On a trip to the Caribbean, you wake with a fever and achy, swollen joints that you can’t blame on too many piña coladas. You might suffer from a headache, muscle pain, nausea or a rash. All you want to do is crawl back into your hotel bed and hide in your hermit shell.

Based on your symptoms, you can rule out heat stroke and hangover. A more likely diagnosis: the chikungunya virus.

“People notice that they’re well one minute, and then they’re unwell” said Erin Staples, a medical epidemiologist at the Centers for Disease Control and Prevention.

Last year was rough for island locals and visitors. The mosquito-borne virus, which first appeared in Africa in the 1950s and later spread to Asia, Europe and India, didn’t surface in the Caribbean until late 2013. Then it made up for lost time. Since the initial findings on the French half of the island of St. Martin, the Pan American Health Organization has tracked more than 1.2 million probable cases in 44 countries and territories throughout the Americas. The CDC lists 25 Caribbean destinations — from Anguilla to the U.S. Virgin Islands — with instances of chikungunya.

“It was easier to talk about islands that didn’t have cases,” Staples said.

Fortunately, the virus has slowed its Carib-wide invasion. Last year, for instance, Martinique reported 73,000 cases; this year, the number has dropped to 320. (One caveat: Because of lapses in information, the counts are not exact.) The bug has been shifting its course to the west and south. In May, the CDC added Mexico, Central America and South America to its “Watch Level 1, Practice Usual Precautions” category. The Caribbean also made an appearance.

Despite the receding figures, chikungunya is still a threat, especially among individuals who have never contracted the virus. (As with chicken pox, once you have been infected, you are immune for life.) Visitors with health issues should also be vigilant.

The mosquitoes that carry chikun­gunya are most active during the day — a departure from the maxim of dusk and dawn — and breed in coastal regions as well as water-filled containers in residential areas. The two species are less prevalent in forested areas, but hikers should still remain on guard. The incubation period lasts a few days, and the symptoms typically remain for up to two weeks. There is no vaccine or treatment, but to ease the discomfort, Staples recommends taking acetaminophen (such as Tylenol), drinking liquids and resting. She also stresses preventive measures.

“Avoid mosquito bites,” she said simply.

The best way to avoid chikungunya is to use insect repellent whenever you are outdoors and to close windows and screens when you are inside. For bug spray, the CDC recommends products registered with the Environmental Protection Agency, such as brands that contain DEET, picaridin and lemon eucalyptus oil. Staples said to apply the cream or to spritz it over your sunscreen and reapply as needed, based on the concentration of the active ingredients.

Keeping mosquitoes away has additional benefits, such as reducing your risk of contracting West Nile virus, dengue fever and malaria — increasing your odds of enjoying an ailment-free Caribbean vacation.

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