You may want to read this before planning your next vacation. A mosquito-borne virus is rapidly spreading throughout the Caribbean, with 4,000 cases already confirmed. Most of the cases of the fast spreading chikungunya virus are in the French Caribbean islands of Martinique, Guadeloupe, and St. Martin, but there are 31,000 suspected cases of the virus throughout the entire Caribbean region. U.S. officials are preparing in case the virus reaches American shores.

The number of cases of chikungunya virus is expected to grow as many countries begin to enter their wettest months, Yahoo News reported. The virus spreads to humans via Aedes aegypti mosquitoes that thrive in the Caribbean’s stagnant waters. St. Vincent and the Grenadines and Antigua and Barbuda became the latest Caribbean countries to confirm reports of the virus. There are already 17 confirmed cases and over 3,000 suspected cases in the Dominican Republic. There are also several suspected cases in Haiti, although none have been confirmed yet.

Chikungunya causes fever, severe joint paint, muscle pain, headache, nausea, fatigue, and rash. There is no cure for the illness, and treatment is mainly focused on relieving the symptoms. Most people are able to recover fully in a few days or weeks, but the joint pain is known to last up to years. In older victims, the disease can contribute to cause of death.

The Centers for Disease Control and Prevention has been monitoring the outbreak and looking for signs of a possible spread to American soil. “To help prepare the United States for possible introduction of the virus, CDC has been working with state health departments to increase awareness about chikungunya and to facilitate diagnostic testing and early detection of any U.S cases,” Dr. Erin Staples explained, Yahoo News reported.

If is often difficult to eradicate a virus once it has begun to spread as rapidly as chikungunya. In the Caribbean, residents are advised to install screened windows and to take steps to ensure that mosquitoes are not breeding in stagnant water. This week, representatives from Central American countries and health authorities met at a two-day conference in the Dominican Republic to discuss the outbreak.