At Machu Picchu, the bites come from tiny flies on the terraces.
- Travel clinic CDC recommends medicine or vaccines for some areas · which ones
- No CDC travel notice for mosquito-borne disease
Cusco tends to be too high for mosquitoes to be much trouble, and the CDC recommends neither malaria medicine nor yellow fever vaccine for the city, the Inca Trail or Machu Picchu. What visitors bring home are itchy welts from daytime flies at the site, so cover your legs and stay off the grass.
A few, mostly in Aguas Calientes at dusk. The bites most visitors bring home come from tiny flies on Machu Picchu's grass terraces, which bite in daylight in every month and itch for days. The CDC recommends neither malaria medicine nor yellow fever vaccine for the city of Cusco, the Inca Trail or Machu Picchu.
The flies on the terraces
Visitors describe tiny flies on the citadel's grass terraces that bite unnoticed during the day and leave welts that show up hours later. Most call them sand flies, though no study has identified them. The sand flies that spread leishmaniasis in Peru bite from dusk to dawn, so flies biting in open midday sun are more likely black flies or biting midges. Our biting-midge guide explains how midges behave.
Wear long trousers and socks rather than cropped pants, plus long sleeves, and put an EPA-registered repellent (picaridin 20%, DEET 20–30%, oil of lemon eucalyptus 30% or IR3535) on your ankles, neck and hands before you enter. Reapply after a few hours, and don't sit or lie on the grass. If you're bitten, try not to scratch, since scratched bites can scar.
Cusco is high. Aguas Calientes isn't.
Elevation decides the CDC's advice in Peru. Its malaria area is everything below 8,200 ft (2,500 m) east of the Andes, and its yellow fever recommendation covers areas below 7,550 ft (2,300 m) in Cusco region and nine others. Cusco, at about 11,200 ft (3,400 m), and the Sacred Valley sit well above both lines. Aguas Calientes, at about 6,600 ft (2,000 m), sits below both, and the Santa Teresa and Hidroeléctrica end of the Salkantay trek is lower still.
What CDC says: its Peru page lists "the highland tourist areas (the city of Cusco, Machu Picchu, Lake Titicaca)" as free of malaria transmission, and says yellow fever vaccine is not recommended for travel limited to "the highland tourist areas (the city of Cusco, the Inca Trail, and Machu Picchu)." It doesn't name Aguas Calientes, Santa Teresa or Hidroeléctrica. What we suggest you do with this: if you'll sleep in any of them, ask a travel clinic 4–6 weeks before departure to check those stops against the CDC's maps. Peru does not require the vaccine for entry.
Dengue stays in the low jungle
Cusco region's dengue sits almost entirely below the tourist circuit. Through late September (epidemiological week 38), Peru's national epidemiology center counted about 450 cases in the region, a rate about a sixth of the national one. Most came from the low jungle of La Convención province, led by Santa Ana (Quillabamba) with 215. The city of Cusco had 3, and all the region's smaller districts combined, Machu Picchu, Santa Teresa and the Sacred Valley among them, had 4. Leishmaniasis follows the same low-jungle pattern, and Machu Picchu district wasn't on the 2026 list.
Continuing to Puerto Maldonado, Manu or Quillabamba changes the advice, and our Peruvian Amazon briefing covers it. Up in Cusco, the thin air is a bigger health question than insects. Cusco also has cases in Peru's 2026 measles outbreak, and the CDC's global measles notice asks all international travelers to be fully vaccinated with MMR.
When to go
The terrace flies bite in every month, and Cusco is low-risk in any season. The dry season, roughly May to September, is the main travel window, and the rainy months run about November to March. The Classic Inca Trail usually closes each February for maintenance.
Where you're going
The citadel & its grass terraces
CDC names Machu Picchu as outside both its malaria area and its yellow fever recommendation. The flies work the grass terraces by day in every month, so keep off the grass and keep your ankles covered.
Aguas Calientes
The town below the site, at about 6,600 ft (2,000 m), isn't named by CDC and sits below its elevation lines. Its outdoor restaurants have a reputation for mosquitoes at dusk, so wear repellent to dinner.
The Classic Inca Trail
CDC does not recommend yellow fever vaccine for the Inca Trail. The trail has a reputation for few bites, nights included, with the flies waiting at the site itself.
Santa Teresa & Hidroeléctrica
The low valley at the end of the Salkantay trek isn't named by CDC and sits below its yellow fever and malaria lines. Santa Teresa district reported 4 leishmaniasis cases in 2026, so put this stop on the clinic list.
Our Peru briefing covers Lima and the rest of the country.
The Machu Picchu kit
- Picaridin 20% travel sprays: odorless, layers over sunscreen and fits a daypack for a top-up on the terraces.
- Permethrin 0.5% for trousers and socks: treat them at home 48 hours before you fly. It goes on clothing, never on skin.
- An antihistamine and hydrocortisone cream for the bites you didn't feel at the time.
What travelers report
Paraphrased from TripAdvisor threads and reviews and linked so you can read them in full. None gives a year, and bite luck at the site varies a lot from one visitor to the next.
- Machu Picchu
Replies to a traveler worried about sand flies said experiences vary widely: some got no bites, while others found bites hours or days later without noticing anything at the site. The advice was long sleeves and pants, repellent on exposed skin, staying off the grass terraces where the flies gather, and carrying antihistamines. TripAdvisor ↗
- Machu Picchu (site review)
A reviewer of the Machu Picchu site led the review with a warning to beware of the sand flies. TripAdvisor ↗
- Sacred Valley
In a thread about sand flies and mosquitoes in the Sacred Valley, a reply said visitors will find mosquitoes, but more at Machu Picchu than in the Sacred Valley. TripAdvisor ↗
- Classic Inca Trail
In a thread asking about bugs on the Inca Trail at night, a hiker said they had no bugs at night while on the trail. TripAdvisor ↗
- Machu Picchu
A traveler started a thread asking for help with scarring left by sand-fly bites from Machu Picchu. TripAdvisor ↗
One rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them where you were in Peru, including any nights in Aguas Calientes or the jungle.
Traveler questions
Do I need malaria pills or a yellow fever vaccine for Machu Picchu?
Not for Cusco, the Inca Trail or the site itself, according to the CDC. It lists the city of Cusco and Machu Picchu among the highland tourist areas with no malaria transmission, and says yellow fever vaccine is not recommended for travel limited to the city of Cusco, the Inca Trail and Machu Picchu. Peru does not require the vaccine for entry. If you're sleeping in Aguas Calientes, hiking down to Santa Teresa or adding the Amazon, see a travel clinic 4–6 weeks before departure.
What are the tiny biting flies at Machu Picchu?
No study has identified them. Visitors usually call them sand flies, but the sand flies that spread disease in Peru bite from dusk to dawn, and these bite in daylight out in the open, which fits black flies or biting midges better. The same routine works either way, with long trousers and socks, long sleeves, repellent on ankles, neck and hands, and no sitting on the grass terraces.
Is Aguas Calientes inside the CDC's yellow fever or malaria areas?
The CDC's Peru page doesn't say. It excludes Machu Picchu by name but doesn't mention Aguas Calientes, which sits at about 6,600 ft (2,000 m), below the 7,550 ft (2,300 m) yellow fever line and the 8,200 ft (2,500 m) malaria line it draws east of the Andes. Santa Teresa and Hidroeléctrica sit lower still. If you'll sleep in either, ask a travel clinic to check them against the CDC's maps.
Are there mosquitoes in Cusco?
Very few. The city sits at about 11,200 ft (3,400 m), which tends to be too high and cold for mosquitoes to be much of a problem, and the CDC lists no malaria there. Cusco region's dengue cases come almost entirely from its low jungle districts, far below the city. At that altitude, the thin air is the bigger health question.
Sources
Health authorities, surveillance reports and news coverage of official bulletins used for this briefing, last checked October 2026. Traveler reports are linked where they appear. This page summarizes public-health guidance and is not medical advice.
- CDC destination page for travelers
- Government source (dge.gob.pe)
- Government source (dge.gob.pe)
- Government source (dge.gob.pe)
- Government source (cdn.www.gob.pe)
- Pan American Health Organization (PAHO)
- Pan American Health Organization (PAHO)
- CDC Travel Health Notice
- Peer-reviewed study (PubMed Central)
- CDC Yellow Book 2026
- millionmilesecrets.com
- Government source (epipublic.dge.gob.pe)
- Government source (epipublic.dge.gob.pe)
- Pan American Health Organization (PAHO)
- Pan American Health Organization (PAHO)
- Health authority (consultorsalud.com)
- Government source (cdn.www.gob.pe)
- rpp.pe
- Government source (cdn.www.gob.pe)
- exitosanoticias.pe
- European Centre for Disease Prevention and Control
- World Health Organization
- Government source (gob.pe)
- Government source (gob.pe)
- CDC Travel Health Notice