Costa Rica is a tropical country and there is a risk of malaria in certain areas. Travelers should speak with their travel health professional about where, exactly, they will be traveling and their personal risk.
Malaria is a mosquito-borne illness and spread through the bite of an infected mosquito. Obviously, limiting exposure to biting mosquitoes is critical in preventing malaria.
The malaria risk areas in Costa Rica generally include Alajuela, Limón, Guanacaste, and Heredia provinces. There is no risk in Limón city (Puerto Limón). This information can change depending on season, rainfall and the unpredictable nature of mosquitoes.
The advised medication for malaria prevention in Costa Rica is chloroquine.
Dengue fever is a viral illness spread by the bites of mosquitoes. Typical symptoms are similar to a flu-like illness, often accompanied with a rash. There is no effective vaccine against dengue. A traveler can take steps to prevent dengue fever by avoiding mosquito bites. Read more about Dengue Fever here.
Chagas disease (American trypanosomiasis) is another insect-borne illness transmitted by the Reduviid bug. In Central America the insect is also known as a “chinche“ bug, although other local nicknames may be commonly used. Primarily an infection associated with rural locations, these insects like to live in poorly constructed houses. Travelers may be at risk should they be visiting these locations and especially if sleeping in these types of “un-improved“ houses.
Victims usually acquire the infection through the bug biting the skin and then defecating while feeding. The person then swats at the bug that is biting them, grinding the insect feces into the freshly made bite-wound. (ewww!)
Most infections are mild and feature fatigue, lymph node swelling and fevers, although 20-30% can have further complications later in life. This infection is diagnosed with a blood test and treated with a special type of antibiotic.
Leptospirosis is a microscopic spirochete that affects travelers who come into contact with infected fresh water. Travelers who participate in outdoor sports such as whitewater rafting, kayaking, lake/river swimmers, hikers and bikers who venture off-road are considered at risk.
This organism penetrates skin and often gets some help when infected water is splashed onto skinned or scraped surfaces such as knees or elbows. Adventurous travelers can acquire this from water sources even as small as a puddle because it is spread through infected animal urine. Basically, anywhere an animal may urinate that has water nearby can be risky.
Symptoms of leptospirosis can vary widely, based on over 100 different types of infectious organisms. Common symptoms include muscle aches (especially of the legs), a yellowing of the skin, fever and reddening of the eyes.
Travelers at especially high risk can speak with their travel doc about taking a weekly dose of the antibiotic doxycycline to prevent illness. Doxycycline can promote sunburns and sun sensitivity and may also cause vaginal yeast infections (thrush) in women.
So, you've read this far, and now you're thingking - 'What? There's even more to beware of?' Well, here's a small bit of good news! There is no yellow fever risk in Costa Rica. Travelers coming in from other countries with yellow fever will be required to show prior immunization.
These organizations have great websites that list English speaking doctors in the area:
Also, check out the Centre for Disease Control for the latest Costa Rica health advice.