Buenos Aires went from record dengue to almost none. Summer still calls for repellent.
- No CDC travel notice for mosquito-borne disease
The city and province had about 132,000 dengue cases in the 2023/24 season and a few dozen in 2025/26, and every confirmed case so far in the 2026/27 season was in a traveler. No vaccine or malaria medicine is needed. Pack repellent from home and use it from February on.
Yes, mostly from February to April, late in the southern summer, which is also dengue season. The last season was tiny, with 32 confirmed cases in the city, and the confirmed cases so far in the 2026/27 season are all in travelers. For a December–April trip, plan on daytime repellent from February, and pack it from home.
From a record season to a tiny one
The 2023/24 season was Argentina's largest since dengue re-emerged in 1997. By the health ministry's preliminary count, the City of Buenos Aires had 25,346 cases and Buenos Aires province 106,932. Shops ran out of repellent during that outbreak.
The 2025/26 season, which ended in late July, looked nothing like it. Argentina's national epidemiological bulletin counted 32 laboratory-confirmed cases in the city, 23 of them without travel history, plus 29 probable cases, and 16 confirmed in the province. Chikungunya, which hit the northwest hard in 2026, reached the city with 13 cases and the province with 51.
The 2026/27 season began in August. By mid-October the ministry had confirmed 1 case in the city and 3 in the province, all in travelers, plus 1 probable case without travel history in the province. Its scenarios for the national season range from under 20,000 to more than 600,000 cases, and it says the early data can't predict which. PAHO warned in October that El Niño is intensifying ahead of South America's peak season, so check the latest bulletin before a February–April trip.
Two mosquitoes, two problems
The dengue mosquito, Aedes aegypti, breeds in containers around homes and patios in summer and bites in daylight, with peaks after sunrise and in the late afternoon. From February on, put repellent on in the morning and again before an evening outdoors in Palermo's parks, at a patio asado or on a delta boat trip at Tigre. Our dengue & Zika routine has the full schedule.
The swarms that made headlines in February 2024 were a different species. After heavy rain, the floodwater mosquito Aedes albifasciatus hatched in huge numbers from flooded ground around the metro area. Researchers quoted in the Argentine press described it as a wild species that doesn't transmit dengue, larger and more aggressive, with a more painful bite, and said such swarms fade within about a week to 10 days. If you land during one, cover up at dusk and keep the windows closed.
The ministry's August 2026 bulletin also confirmed 5 cases of St. Louis encephalitis, another mosquito-borne virus, in Buenos Aires province in 2025/26. It confirmed no locally acquired West Nile cases in Argentina; its one confirmed case, treated in the province, was a visitor from Kansas. Those are small numbers, and the same repellent routine covers them.
No vaccine for the city
What CDC says: its Argentina page has no malaria section, and says yellow fever vaccine "is not recommended for travel limited to provinces and areas not listed above," which covers the City and Province of Buenos Aires. It recommends the vaccine only for Misiones and Corrientes, and "Chikungunya vaccination is generally not recommended." What we suggest you do with this: there's nothing to book for Buenos Aires alone. If Iguazú Falls is on the route, see a travel clinic 4–6 weeks before departure; our Iguazú Falls briefing covers it.
Where you're going
Palermo & Recoleta
Parks and leafy blocks. City figures apply here, with 32 confirmed dengue cases in 2025/26. From February on, put on repellent before an afternoon in the Palermo parks.
San Telmo & La Boca
The historic south side, with no neighborhood dengue figures published. The daytime routine is the same as anywhere in the city.
Costanera Sur & Puerto Madero
A riverside wetland reserve beside the docks, likely buggier at dusk than the rest of the city. Go earlier in the day, or bring repellent and long sleeves.
Tigre & the Paraná Delta
Islands and channels in Buenos Aires province, which had 16 confirmed dengue cases in 2025/26. Floodplain like this likely suits floodwater mosquitoes, so put on repellent before an evening boat trip.
Our Argentina briefing covers Mendoza and Patagonia.
The Buenos Aires kit
- Picaridin 20% travel sprays: odorless, layers over sunscreen and fits a day bag for parks and the delta. One 3.4 oz bottle covers about a week of daily use for one person.
- A full-size backup in the checked bag for a family or a February–March stay.
- A light long-sleeved layer for dusk if you land during a floodwater swarm.
What travelers report
Paraphrased from TripAdvisor threads and linked so you can read them in full. Only one is dated, to February 2024, the summer of the swarms, and most weeks are much calmer.
- Buenos Aires · February · 2024
In a February 2024 thread about a mosquito invasion, posters cited press reports of a mosquito population peak and a high official dengue-risk rating for the city, and noted that the swarming species was not the one that carries dengue, though that one was present too. TripAdvisor ↗
- Buenos Aires · late February to early March
A traveler who attracts mosquitoes asked about a six-day visit at the end of February and start of March. A destination expert said to expect mosquitoes then, with numbers depending on the preceding weeks' weather, said yellow fever shots and malaria pills were not needed, and called dengue a very slim but present risk; another reply advised bringing repellent from home because shortages were likely. TripAdvisor ↗
- Buenos Aires
A poster in the city said bug spray could not be found and asked travelers heading home to leave their spare DEET. TripAdvisor ↗
One rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them you were in Buenos Aires, plus anywhere else in Argentina you went.
Traveler questions
Is there dengue in Buenos Aires right now?
Very little. The city had 32 laboratory-confirmed cases in the whole 2025/26 season, and by mid-October 2026 the new season had 1 confirmed case in the city and 3 in the province, all in travelers. The health ministry's scenarios for 2026/27 range from under 20,000 to more than 600,000 cases nationally, and it says the early data can't predict which. Check the latest Boletín Epidemiológico Nacional before a February–April trip.
Do I need vaccines or malaria pills for Buenos Aires?
The CDC lists no malaria for Argentina and does not recommend yellow fever vaccine for travel limited to provinces outside its list, which covers the City and Province of Buenos Aires. It recommends the vaccine for Misiones and Corrientes, so adding Iguazú Falls changes the answer. Argentina does not require it for entry, and the CDC says chikungunya vaccination is generally not recommended.
What was the 2024 mosquito invasion?
In February 2024, after heavy rain, swarms of a floodwater mosquito, Aedes albifasciatus, hatched from flooded ground around the metro area. Researchers quoted in the Argentine press described it as a wild species that doesn't transmit dengue, with a more painful bite, and said such swarms fade within about a week to 10 days. If you land during one, cover up at dusk and keep the windows closed.
When are mosquitoes worst in Buenos Aires?
Late summer. December and early January are usually quiet, and dengue risk builds from February to a peak in March and April. Floodwater swarms follow heavy rain, so a wet spell matters more than the date. Parks, the Costanera Sur wetlands and the delta at Tigre are the likeliest spots for evening bites.
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 (argentina.gob.ar)
- Government source (argentina.gob.ar)
- Government source (argentina.gob.ar)
- Pan American Health Organization (PAHO)
- CDC Travel Health Notice
- ambito.com
- minutouno.com
- news.agrofy.com.ar
- Pan American Health Organization (PAHO)
- Pan American Health Organization (PAHO)
- European Centre for Disease Prevention and Control
- CDC destination page for travelers