Mosquitoes in Portugal: mostly a sleep problem, with two newcomers to know
Lisbon has just released tens of thousands of sterile mosquitoes to fight an invader most visitors have never heard of. What actually bites in Portugal, where the Asian tiger mosquito has spread, why Madeira is a different file, and what to ask for at the farmácia.
Mainland Portugal is a comfort question, not a health one. No locally acquired dengue, chikungunya or Zika has been reported there, and the common house mosquito mostly costs you sleep from May to October. The newcomer is the Asian tiger mosquito, a daytime biter now recorded in at least 28 mainland municipalities, Lisbon included. Madeira is a different file: the dengue mosquito lives in Funchal, behind a 2,000-case outbreak in 2012 and two local cases in 2025. Bringing a dog? Sandflies spread leishmaniasis to dogs across the country, so see a vet before you arrive.
Why Lisbon is releasing mosquitoes
On 24 September 2026, researchers released 30,000 sterile male Asian tiger mosquitoes in Lisbon's Alvalade parish, the final batch of a first trial phase. Male mosquitoes don't bite. They mate with wild females, the eggs never hatch, and over successive releases the local population should shrink. The first phase measures how far the sterile males travel and how long they live in a real city; a second phase, comparing a release area with an untreated one, is planned for May 2027 if the results hold up.
The partners are Portugal's national health authority (DGS) and health institute (INSA), Lisbon city council, the Alvalade parish council and the public-health unit of the Santa Maria hospital group, with funding from the International Atomic Energy Agency, which backs the sterile insect technique worldwide. For a visitor, the headline isn't alarming; it's informative. You don't run a project like this for a mosquito that isn't there.
The newcomer's passport
Aedes albopictus, the Asian tiger mosquito, arrives the way it has arrived across southern Europe: as eggs in used tyres and potted plants, then a few backyards at a time. Portugal's mosquito surveillance network (REVIVE, run by INSA) has stamped each new arrival:
Sources: INSA REVIVE 2025 report (April 2026); RTP, 14 September 2026.
Two things make this species different from the mosquitoes Portugal already had. It bites by day, mainly in the morning and late afternoon, with adults around from April or May into November. And it's the species that carried the locally acquired dengue and chikungunya outbreaks France and Italy have seen in recent summers. Portugal hasn't had a single locally acquired case on the mainland, and DGS rates the tiger mosquito's presence at level 1 of 3. So the practical upshot is modest: if something bites your ankles at lunch on an Algarve terrace or in a Lisbon garden, that's probably the newcomer, and a coat of repellent in the morning handles it.
Who bites when
The tiger mosquito
Small, black with bright white stripes, low and fast. Breeds in tiny pockets of water: saucers under plant pots, gutters, bottle caps, tyres.
Peaks in the morning and late afternoon, April or May to November.
The house mosquito
Culex pipiens is the most common mosquito in every region of Portugal, active all season with peaks in July and October. Females overwinter indoors, which explains the odd January whine in an apartment.
Near coastal salt marshes and lagoons, a second night shift, Ochlerotatus caspius, bites harder still.
Night biters are where most Portugal holidays actually suffer. The fixes are the boring ones from our Dutch bedroom-war briefing: windows shut at dusk with the lights on, a plug-in vaporizer for the bedroom, and a fan across the bed. Outdoors, one coat of picaridin or DEET at dinner time covers the terrace hours.
Madeira is a different file
The dengue mosquito lives here. Aedes aegypti, the main carrier of dengue worldwide, was found in Funchal in 2005 and is now established in Funchal and Câmara de Lobos. In 2012 it drove an outbreak of more than 2,000 cases (121 hospitalised, no deaths), with dozens more exported to the mainland and elsewhere in Europe. In January 2025 dengue virus turned up again in mosquitoes in Funchal, and two locally acquired cases were reported that February; no positive mosquito samples have been found since. ECDC's 2025 count lists exactly those two cases.
That's not a reason to skip Madeira; the island's health authorities run one of the most watched mosquito programs in Europe precisely because of 2012. It is a reason to bring tropical habits to a European island: repellent at breakfast, over sunscreen, re-applied through the day, because Aedes aegypti bites in daylight. The full routine is in our dengue-zone daily plan. Traveling with small children? The age rules are in our babies and kids guide.
The dog paragraph
Sandflies, not mosquitoes, are Portugal's real pet risk. Leishmaniasis is endemic, dogs are its main reservoir, and the tiny sandfly Phlebotomus perniciosus spreads it between dusk and dawn from about May to October. In a 2021 national study, 12.5% of 1,860 dogs tested positive for antibodies, with higher odds for dogs living inland, dogs aged two or older, and dogs without repellent protection. Book a vet visit before you travel: ask about an insecticidal collar or spot-on rated for sandflies and about vaccination, and keep evening walks short in sandfly season. People catch it far more rarely (221 visceral cases in Portuguese public hospitals from 2010 to 2020), and the same night-time repellent that handles mosquitoes covers sandfly bites.
West Nile, briefly
West Nile virus circulates in Portugal mostly among birds and horses: veterinary authorities recorded 13 equine cases in Ribatejo and Alentejo in 2023 and confirmed circulation in the Santarém, Setúbal, Évora, Beja and Portalegre districts in 2024, and again in 2025. Human cases are rare: the last confirmed one was in the Algarve in 2015. Your dusk repellent already covers it, and it's the same quiet footnote we give mainland Greece.
The farmácia card
Portuguese pharmacies and supermarkets stock plenty of repellent, mostly DEET and IR3535. Picaridin, sold in Europe as icaridina, is harder to find: in consumer group DECO PROteste's June 2026 comparison of 11 repellents on Portuguese shelves, one was icaridin-based (Parasidose 20%), alongside DEET products from Autan, Jungle Formula and Previpiq, IR3535 sprays from Wells and Bodyguard, and a 10% lemon eucalyptus spray from Decathlon's Forclaz line. Repellents in Portugal are authorized by the DGS, so anything on a pharmacy shelf is legitimate. If you prefer picaridin, pack your own: a 100 ml bottle rides in your carry-on.
The Portugal kit
- One 3.4 oz (100 ml) picaridin spray for terrace evenings and tiger-mosquito mornings; local shelves lean DEET.
- A plug-in vaporizer for the bedroom: buy it on arrival at any supermarket or farmácia.
- Madeira: make repellent at breakfast, over sunscreen, a daily habit.
- Dogs: vet-prescribed sandfly protection, fitted before the trip.
Traveler questions
Are there mosquitoes in Lisbon?
Yes. The common house mosquito bites at night from about May to October, and since 2023 the Asian tiger mosquito, a daytime biter, has been found in Lisbon and Oeiras. No locally acquired mosquito-borne disease has been reported on mainland Portugal, so for visitors it is a comfort question: a repellent for evenings and a plug-in vaporizer for the bedroom.
Is there dengue in Portugal?
Not on the mainland, where no locally acquired cases have been reported. Madeira is different: the dengue mosquito Aedes aegypti has lived in Funchal since about 2005, caused an outbreak of more than 2,000 cases in 2012, and two locally acquired cases were reported in Funchal in early 2025. On Madeira, use repellent during the day as well as in the evening.
Do I need mosquito repellent in the Algarve?
Mostly for comfort. Evenings from May to October bring house mosquitoes, salt-marsh mosquitoes bite hard near coastal lagoons, and the Asian tiger mosquito has been recorded in a dozen Algarve municipalities including Faro, Lagos, Portimão, Albufeira and Tavira. One bottle of picaridin or DEET covers a typical holiday.
What mosquito repellent can I buy in Portugal?
Pharmacies and supermarkets mostly sell DEET products (for example Autan Tropical, Jungle Formula and Previpiq), IR3535 products, and a few lemon eucalyptus sprays. Icaridin, the European name for picaridin, is harder to find: only one of the 11 repellents in DECO PROteste's June 2026 comparison used it. Ask for repelente com icaridina, or pack your own.
Is leishmaniasis a risk for dogs in Portugal?
Yes. Leishmaniasis is endemic in Portugal, dogs are its main reservoir, and sandflies spread it between dusk and dawn from about May to October. A 2021 national study found 12.5% of dogs tested positive for antibodies. Ask a vet about an insecticidal collar or spot-on and vaccination before you arrive, and avoid dusk-to-dawn walks in sandfly season.
Sources: INSA REVIVE 2025 report; DGS guidance 003/2024; ECDC dengue and chikungunya surveillance (as of 21 October 2026); DECO PROteste repellent comparison (June 2026); Rocha et al. 2024 and Almeida et al. 2022 on leishmaniasis; DGAV equine West Nile notices. Health information summarizes official sources and is not medical or veterinary advice.