What is it?
Chikungunya (chik-en-gun-ye) is a mosquito-borne virus that causes fever and joint pain. According to the World Health Organization, it was first identified in Tanzania in 1952, and outbreaks have occurred throughout Asia and Africa, often in cycles.
In recent years, the virus has progressively moved north. A village in Italy suffered an outbreak in 2007, and in late 2013 the first case of chikungunya was recorded in the Americas, with several people in St. Martin falling ill.
Where is it?
As of late June 2014, cases of chikungunya have been identified in 22 countries in North America, including much of the Caribbean. (The CDC updates these figures every Tuesday night.) As of July, islands with cruise ports that have experienced the outbreak include Antigua, the British Virgin Islands, Guadeloupe, Haiti, Puerto Rico, St. Kitts, St. Lucia, St. Vincent/Grenandines, Turks & Caicos, the U.S. Virgin Islands, the Dominican Republic, St. Martin/St. Maarten, Martinique, St. Barts and Dominica.
The U.S. and Mexico have reported several cases of "imported" chikungunya, meaning that the people who got it had already been bitten before they came back home. Authorities in Florida are bracing for the disease to spread, with the state Department of Health placing information about chikungunya and its symptoms on their website.
How does it spread?
Chikungunya is spread through bites from the Aedes mosquito, which is also a carrier for dengue fever. (Although dengue is considered a more serious illness than chikungunya, the latter appears to spread more easily.) If a mosquito bites a person who is contaminated with the virus, they can become a carrier. These mosquitoes tend to bite more in the daytime than at night, according to the Centers for Disease Control.
What are the symptoms?
The most common symptoms of chikungunya are fever and severe joint pain in the hands and feet, along with headaches, muscle pain, joint swelling or rash. The problems emerge between three to seven days after being bitten, which is why cruise passengers may not discover it until after their trip.
If you suffer symptoms, go immediately to your doctor for a blood test.
Read more about what to do if you get sick at sea.
What kind of treatment is there?
There is no medicine specifically developed to treat chikungunya, nor are there vaccines to prevent it. If you contact these symptoms after a cruise, go to your doctor for testing. They will recommend rest, fluids and possibly aspirin and anti-inflammatories, once dengue fever has been ruled out.
People usually feel better after a week, and death is rare.
Who is most susceptible?
People with compromised immune systems -- usually the very old, the very young and those with serious chronic conditions like high blood pressure, diabetes and heart disease -- may develop more serious, long-term joint pain.
What precautions can I take?
As there is no vaccine against chikungunya, your best defense is to wear mosquito repellant with an active ingredient (like DEET or Picaridin) on exposed skin when visiting Caribbean ports, particularly if you're venturing into areas with standing water. (The general rule is to put on your sunscreen first, then put on the insect repellent.) Cover up with long-sleeved shirts and long pants, or wear clothing treated with Permethrin.
Read more about staying healthy on a cruise.
Are there other mosquito-borne diseases I should watch out for?
Dengue fever has long plagued the world's tropics and subtropics; the disease can be fatal, and there is no cure. Cruisers heading to affected areas should always check the Travelers Health section of the CDC website to see which regions in their destinations have the most risk and follow precautions against being bitten. For more on dengue, read the CDC's special section on the disease.
Malaria is another potentially deadly disease, but this one, luckily, can be prevented (and the mosquitos that carry it bite mostly at night, which is good news for day-trippers). If you're spending serious time in malaria zones, getting -- and taking -- prescription antimalarial medication is a good idea.
Different types of mosquitos require different medications, so be sure to tell your doctor exactly where you'll be traveling so you get the right one. Most require you to start taking them at least a day or so before your trip and up to a week after you return. Also read up on side effects; antimalarials can be strong and cause diarrhea, blurred vision, sunlight sensitivity and vivid dreams. For more on malaria, read the CDC's Resources for Travelers guide.
Yellow Fever has historically been one of the most dangerous mosquito-borne viruses. (More than 41,000 people died of epidemics in New Orleans alone between 1817 and 1905.) It's still common in tropical areas of South America and Africa, with its carrier mosquito biting in the early morning or late afternoon. A vaccine, which conveys lifelong immunity, has been commonly available since the 1950s. Travelers should get the shot at least 10 days before they arrive in an area with Yellow Fever.