In Brazil, dengue is a daily habit. Yellow fever is a clinic visit.

A typical first trip to Brazil starts in Rio de Janeiro and adds Iguaçu Falls, Salvador, or a wildlife leg in the Amazon or the Pantanal. Dengue reaches all of them. The planning item is yellow fever, because the CDC's vaccine recommendation reaches well beyond the jungle, to the cities of Rio de Janeiro and São Paulo and to the falls. Malaria advice stays in the Amazon and the states around it.

Dengue is the everyday item

Brazil reports most of the dengue cases in the Americas, and all four dengue types are circulating in 2026, according to the Pan American Health Organization. The record year was 2024. By early June that year the health ministry counted more than 6 million probable cases and 3,542 confirmed deaths, the highest since its records began in 2000, and PAHO's tally of all reported cases for 2024 runs considerably higher. 2025 was a normal, non-epidemic year by comparison, with about 1.66 million probable cases.

This year is well below the record but still very high. PAHO data compiled by the European Centre for Disease Prevention and Control showed about 1.3 million cases by early September, again by far the most in the region.

The mosquito behind dengue and chikungunya, Aedes aegypti, bites in daylight, with peaks after sunrise and before sunset. Our dengue & Zika daily routine has the full schedule. On a Brazil trip it comes down to three habits.

Yellow fever reaches most of the map

The CDC recommends yellow fever vaccine for travelers 9 months and older going to the states of Acre, Amapá, Amazonas, Distrito Federal (including Brasília), Espírito Santo, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Minas Gerais, Pará, Paraná, Piauí, Rio de Janeiro (including the city and all coastal islands), Rio Grande do Sul, Rondônia, Roraima, Santa Catarina, São Paulo (including the city and all coastal islands) and Tocantins, to designated areas of Bahia, and to Iguaçu Falls. It does not recommend it for travel limited to areas not listed, including the cities of Fortaleza and Recife. Brazil does not require the vaccine for entry.

For the usual itineraries, that puts Rio, São Paulo, Iguaçu Falls, Brasília, Manaus and the Pantanal inside the recommendation. Salvador is less clear. Bahia is listed only for designated areas, so ask the clinic to check the CDC's map for the city.

PAHO counted 120 confirmed cases and 48 deaths in 2025. São Paulo state had 61 cases and 35 deaths, in 29 municipalities around Campinas, Bragança Paulista, Joanópolis and the Paraíba Valley. Most of the rest were in Pará and southern Minas Gerais. Only one patient had been vaccinated. The last 2025 case fell ill on June 22, and PAHO had no confirmed cases in the first seven weeks of 2026, though WHO later listed Brazil among the countries that reported cases between January and May 2026.

Malaria stays in the Amazon

The CDC's malaria map is much smaller. It reports transmission in all areas of Acre, Amapá, Amazonas, Rondônia and Roraima, and in Maranhão, Mato Grosso and Pará, where the capitals São Luís, Cuiabá and Belém see only rare cases. For the transmission areas it lists several prevention medicines. There is no malaria transmission in the cities of Rio de Janeiro, São Paulo or Brasília, or at Iguaçu Falls. Rare cases in rural and forested parts of eight other states, Rio de Janeiro and São Paulo among them, call for bite precautions only.

Manaus and the lodges around it are inside the medicine area. The Pantanal needs a closer look. Its northern side, including the Transpantaneira, is in Mato Grosso, which the CDC lists as a transmission state, while the southern side around Campo Grande is in Mato Grosso do Sul, a rare-case state where the CDC recommends bite precautions alone. Ask the clinic to check the CDC's map for your lodge. Our malaria-zone checklist covers the rest of the preparation.

Malaria mosquitoes bite from dusk to dawn. In the Amazon and the Pantanal, that means long sleeves at dusk, permethrin-treated clothing and a screened or netted bed. The same covers protect against the sand flies that spread leishmaniasis, which the CDC lists for Brazil, and the midges that spread Oropouche. Continuing to Peru's Amazon? Our Peru briefing covers its separate malaria and yellow fever lines.

Chikungunya and Oropouche

Chikungunya travels on the same day-biting mosquito as dengue and is active in all 26 states and the Federal District. Through early October 2026, PAHO counted about 136,000 suspected and 56,759 confirmed cases, with 58 deaths, a 41.6% drop from the same weeks of 2025. By August the most affected states were Bahia, Alagoas, Pernambuco, Mato Grosso do Sul and Minas Gerais. The CDC says vaccination may be considered for stays of about six months or more.

Oropouche is a virus spread mainly by the Culicoides paraensis biting midge. Brazil's outbreaks in 2024 and 2025 spread to the Atlantic coast states. PAHO counted 13,785 confirmed cases in 2024 and 11,888 through early August 2025, led by Espírito Santo and Rio de Janeiro state, with five deaths that year. Midges are weak fliers that bite ankles and lower legs at dawn and dusk, so repellent aimed low covers most of the exposure. Our biting-midge guide explains their habits.

Where you're going

Here is how the main stops compare in any month.

When to go

June to September, the southern winter, is the seasonal low for dengue and chikungunya in Rio, São Paulo and Iguaçu, and the dry season in the Pantanal, which is much easier for bites. February to May is the hard stretch in the southeast and center-west. Dengue peaked in late March in 2025, chikungunya kept rising into early April in 2026, and the 2025 yellow fever cases fell ill between early January and late June.

The Amazon is humid all year. In the northeast, chikungunya stayed active in Bahia into August and September 2026. PAHO's October update warns that South America's peak dengue season is approaching as El Niño intensifies, so a trip in the coming months calls for the full daytime routine.

What travelers report

Paraphrased from forum threads and reviews and linked so you can read them in full. None of them gives a year, and individual trips vary with season, weather and where you stay.

• Manaus area jungle trip

  A returning traveler titled their report 'Great Trip. Few Mosquitoes.' after a jungle trip from Manaus. TripAdvisor ↗

• Amazon Ecopark Jungle Lodge, near Manaus

  A guest described the stay as a mosquito-free jungle experience. TripAdvisor ↗

• Southern Pantanal (from Campo Grande) · dry season

  A visitor found fewer mosquitoes during the dry season but still advised bringing DEET or a similar repellent. TripAdvisor ↗

• Pantanal · July

  Asked about mosquitoes on a July trip, a reply said there are small insects in some places but not much in the dry season. TripAdvisor ↗

• Iguaçu Falls

  Answering a question about current mosquito levels at the falls, a poster said the Argentine side was worse than the Brazilian side on a recent visit. TripAdvisor ↗

One more rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them you were in Brazil and which states you visited. Dengue usually shows up within two weeks; malaria can take longer. That one sentence is what gets you the right test quickly.

Traveler questions