Typhoid is present throughout Costa Rica — transmitted via contaminated food and water. Risk is particularly elevated at jungle lodges with non-municipal water supplies, at local sodas (small family restaurants) and markets, and when eating street food. Both injectable (Vi-polysaccharide) and oral (Ty21a) vaccines are available. Administer at least 2 weeks before departure. Vaccine efficacy is approximately 70–80% — standard food and water precautions remain essential.

Hepatitis A is endemic throughout Central America — transmitted via contaminated food and water. A single dose of the Havrix or Vaqta vaccine provides over 95% protection within 2 weeks. The second dose (6–12 months later) provides lifelong protection. The Twinrix combined Hepatitis A+B series is a convenient alternative. One of the most important and consistently underestimated vaccines for Costa Rica travelers.

Rabies is endemic in Costa Rica — primarily from dogs and bats. Pre-exposure prophylaxis (2-dose series, 7 days apart under the updated 2022 CDC schedule) is recommended for jungle lodges, rural hiking, wildlife rehabilitation volunteers, and any traveler spending time away from urban healthcare. Post-exposure treatment is available in San José and major cities but unreliable in remote areas. Bat exposure during night hikes and open-air lodge sleeping is a specific risk.

Before any Costa Rica trip: confirm MMR (2 doses — measles present in Central America), Tdap booster (tetanus is a real risk from jungle cuts), Hepatitis B (if not previously completed), Influenza (annual), and COVID-19 boosters are current. Yellow fever is not endemic in Costa Rica — no vaccine required unless arriving from an endemic country.

🦟 Dengue, Zika & Chikungunya — Three Mosquitoes, One Solution

All three are transmitted by Aedes aegypti — the same daytime mosquito. DEET 30–40% applied every morning protects against all three simultaneously. Zika is of particular concern for pregnant travelers or those planning pregnancy — see our full Latin America Health Guide for the complete Zika guidance. Chikungunya causes fever and joint pain that can persist for months — there is now an FDA-approved vaccine (IXCHIQ) for adults; discuss with your travel physician.

💧 Leptospirosis — The Waterfall Risk You Don't Expect

Leptospirosis is a bacterial infection transmitted through water or soil contaminated with the urine of infected animals — particularly rodents, cattle, and horses. Wading, swimming, or swallowing water at waterfall swimming holes carries real leptospirosis risk, particularly during and after heavy rain when soil runoff increases contamination. Symptoms appear 2–30 days after exposure: high fever, headache, muscle pain, red eyes. Doxycycline prophylaxis (200mg once weekly) is recommended for adventure travelers spending significant time in freshwater. Always wear closed footwear when wading; cover all open cuts before entering freshwater.

🫀 Chagas Disease — The Kissing Bug

Chagas disease (Trypanosoma cruzi) is transmitted by triatomine "kissing bugs" — nocturnal insects that emerge from the cracks of adobe walls, thatched roofs, and rustic wood structures at night to feed on sleeping hosts. Risk to travelers in standard eco-lodges with sealed construction is low — risk increases in rustic jungle accommodation, wooden huts, and budget lodges in rural areas. Sleep in sealed rooms. No vaccine exists. No prophylaxis. Prevention is entirely structural: don't sleep in cracked adobe.

🐍 Venomous Snakes — The Fer-de-Lance

Costa Rica has several venomous snake species — the fer-de-lance (Bothrops asper) is the most dangerous and the most commonly encountered. Excellent at camouflage, typically found on jungle trails, near water, and in leaf litter. Always wear closed boots (not sandals) on jungle trails. Watch where you step and where you place your hands. If bitten: immobilise the limb at heart level, do not suck the venom or apply a tourniquet, and get to a hospital urgently. INS (Instituto Nacional de Seguros) hospitals in Costa Rica stock antivenom.

🐸 Dart Frogs — Beautiful, Don't Touch

Poison dart frogs (Dendrobates and Oophaga species) are among Costa Rica's most spectacular wildlife — bright red, blue, yellow, and orange jewels on the forest floor. In captivity, they lose their toxicity (the poison comes from their wild diet of specific insects). In the wild, their skin secretions cause serious neurological effects. Never touch. Observe from 30 cm. The strawberry poison dart frog (Blue Jeans frog) is the most commonly spotted in the Caribbean lowlands.

🐜 Bullet Ants — The World's Most Painful Sting

The bullet ant (Paraponera clavata) holds a level 4+ rating on Schmidt's insect sting pain scale — described as "pure, intense, brilliant pain, like walking over flaming charcoal with a 3-inch nail embedded in your heel." The pain lasts 24 hours. They are large (2.5 cm), slow-moving, and easy to avoid if you watch where you place your hands on logs and trees. Never grip a tree trunk or log without looking first — bullet ants are frequently found at exactly hand-height. The sting is not medically dangerous for most people; the experience is simply extraordinary in its unpleasantness.

🦟 Malaria — Lower Risk, Still Real

Malaria risk in Costa Rica is significantly lower than in neighbouring Nicaragua or Panama — the main risk areas are the Limón province on the Caribbean coast and remote border areas. For most standard eco-tourist itineraries (Arenal, Manuel Antonio, Monteverde, Osa Peninsula) malaria risk is low but not absent. Discuss antimalarial prophylaxis with your travel physician — many physicians recommend it for Osa Peninsula jungle lodges where Anopheles populations are higher. See our full Malaria Prevention guide.

🌿 Contact Plants — Don't Touch What You Can't Identify

Costa Rica's jungle contains several plants with significant contact dermatitis potential — most notably the manzanillo de playa (manchineel) tree on Pacific beaches (every part including the sap is toxic; standing under it in rain causes chemical burns), and various Dieffenbachia relatives whose sap causes severe oral and skin irritation. Never grab random vegetation on jungle trails for support — always use your trekking pole. If skin contact occurs with an unknown plant, wash immediately with soap and water.

🦋 Blue Morpho Butterfly

The iridescent electric-blue morpho (Morpho peleides) has a wingspan up to 20 cm — the colour is structural (microscopic scales refracting light, not pigment) and visible from 100 metres. Found in lowland rainforest, most easily seen on jungle trails in morning when they bask with wings open. The La Paz Waterfall butterfly garden has guaranteed encounters; in the wild, simply watch the forest floor at Arenal or Osa.

🐸 Red-Eyed Tree Frog

The red-eyed tree frog (Agalychnis callidryas) is Costa Rica's most iconic wildlife image — vivid green body, red eyes, orange feet, blue flanks — and entirely harmless. Nocturnal; found on vegetation near ponds, streams, and waterfalls in lowland rainforest. Night hikes at Tortuguero, La Selva, and Osa Peninsula consistently produce sightings. A photograph of a red-eyed tree frog in the wild on your phone is the Costa Rica wildlife trophy.

🦜 Resplendent Quetzal

The resplendent quetzal (Pharomachrus mocinno) — the most spectacular bird in the Americas, worshipped by the Maya and Aztec as a deity, the male with a 90 cm iridescent green tail — inhabits the cloud forests of Monteverde, Chirripó, and the Cerro de la Muerte at 2,500–3,000 m altitude. January–April breeding season is best. No DEET required at these altitudes — the cold and altitude put you above the mosquito zone entirely.

🦥 Three-Toed Sloth

The three-toed sloth (Bradypus variegatus) moves so slowly that algae grows in its fur, turning it green and providing camouflage. They spend 15–20 hours per day in a single cecropia tree. Spotting one in the wild — usually a grey-green smudge 20 metres up a tall tree — is a skill that a good naturalist guide makes look effortless. The canopy walkway at Manuel Antonio and the sloth sanctuary near Puerto Limón on the Caribbean coast offer reliable sightings.

🐊 American Crocodile

The Tárcoles River bridge on the Pacific highway is the easiest place in the world to see large American crocodiles — 50–80 individuals typically haul out below the bridge, some exceeding 4 metres. This requires only parking your car and walking to the railing. Do not enter the water. Do not approach the riverbank. Do not let children lean over the railing. The crocodiles are entirely wild and entirely indifferent to your welfare.

🦎 Jesus Christ Lizard

The common basilisk (Basiliscus basiliscus) can run across the surface of water on its hind legs for up to 10 metres before sinking — hence its nickname. Found near virtually every waterfall on this list, basking on streamside rocks or exploding from the vegetation at approaching footsteps in a spray of water and scrambling legs. One of the most entertaining and reliably spotted wildlife encounters in Costa Rica. No health risk, completely harmless.