New cases of dengue hemorrhagic fever (DHF) detected this week in Parrita, in the Pacific province of Puntarenas, have Costa Rican health officials on alert.
Although the country has registered 20 cases of DHF so far this year, health officials have treated more than 200 cases of dengue in that area alone.
Health officials last month said that 6,898 cases of dengue have been reported in the country in 2013, a 300 percent increase from the same period in 2012.
The start of the rainy season this weekend will likely increase the number of people infected.
Health officials recommend residents keep backyards clean and free of containers where stagnant water can accumulate, to prevent the Aedes aegypti mosquito, the carrier of dengue, from breeding.
Dengue fever causes fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles.
It can develop into the life-threatening DHF, resulting in bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs. Officials recommend seeing a doctor immediately if any of these symptoms occur.
