According to figures released by the Costa Rican government, a total of 2568 probable or confirmed cases of the Zika virus were registered in the country in the first 40 weeks of the year (period ending October 8). During the same period, 4766 cases of dengue fever and 323 cases of chikungunya were also reported. A nationwide campaign to reduce populations of the Aedes aegypti mosquito, a potential carrier of all three diseases, continues.
While remaining a significant health threat, transmission rates of these three diseases have fallen significantly in 2017. In 2016, a total of 5635 cases of the Zika virus, 22,209 cases of dengue fever, and 3361 cases of chikungunya were reported.
On a related note, eight locally-acquired (autochthonous) cases of malaria, a disease carried by a different type of mosquito, were also diagnosed during the above period.
Although the Zika virus is usually relatively benign, links between it and severe birth defects as well as the potentially fatal neurological disorder Guillain-Barre syndrome (GBS) have been established. The virus is asymptomatic in approximately 80 percent of cases; when symptoms do occur, they generally appear two to seven days after infection, and include fever, headache (behind the eyes), conjunctivitis, rashes, vomiting, and muscle and joint pain. The disease can also be transmitted via sexual intercourse.
Symptoms of dengue fever include fever, headache, muscle and joint pain, fatigue, nausea, and rashes. Dengue Hemorrhagic Fever (DHF) is a potentially deadly complication that is characterized by high fever, the enlargement of the liver, and hemorrhaging.
Symptoms of chikungunya include fever, headache, joint and muscle ache, fatigue, nausea, diarrhea, and rashes. The virus is infrequently fatal but potentially debilitating joint pain can last for weeks, even months, after the initial recovery.
Individuals present in Costa Rica - in particular pregnant women and their partners - are advised to take measures to protect themselves from mosquito bites (e.g. by wearing covering clothing, using insect repellent, and sleeping in screened-in or air conditioned rooms) and to eliminate possible mosquito breeding grounds (small pockets of fresh water, such as rain water that has collected in cans, bottles, tires, flower pots, clogged gutters, etc.).