Zika Virus risk in San José

Zika Virus Prevention Guide for San José, Costa Rica

Risk Score: 59/100 (Moderate)

What is Zika Virus

Zika is a mild viral illness spread primarily through the bite of infected Aedes mosquitoes, the same species that carries dengue and chikungunya. Most people experience mild symptoms like fever, rash, joint pain, and red eyes, though many show no symptoms at all. The serious concern is for pregnant women, as Zika can cause severe birth defects including microcephaly.

Why San José Carries Moderate Risk

San José sits in Costa Rica's Central Valley at roughly 1,100 meters elevation, which keeps temperatures warm year-round. The city's tropical climate, frequent afternoon rains, and abundant standing water sources, flower pots, discarded tires, uncovered water tanks, and potted plant saucers create ideal mosquito breeding grounds. Urban density means more human hosts in concentrated areas. The 59/100 risk score reflects active mosquito populations combined with limited but present community transmission history and seasonal rainfall patterns that peak between May and November.

5 Prevention Steps

1. Eliminate standing water weekly. Empty, scrub, and overturn any container that holds water, including plant saucers, buckets, old tires, and clogged gutters. Aedes mosquitoes breed in as little as a bottle cap of water.

2. Use EPA-registered insect repellent containing DEET, picaridin, or oil of lemon eucalyptus on exposed skin, especially during early morning and late afternoon when these mosquitoes bite most actively.

3. Wear long sleeves and long pants when outdoors, treating clothing with permethrin spray for added protection that lasts through several washes.

4. Ensure windows and doors have intact screens, and use bed nets if sleeping in rooms without air conditioning or proper screening.

5. If pregnant or planning pregnancy, consult your healthcare provider before traveling to or remaining in San José, and take all mosquito bite prevention measures daily without exception.