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The important points, first
- Ticks and fleas do not stop when summer ends: in mild climates and indoors they can be active in autumn and winter too.
- Protection should be planned with your veterinarian based on your pet’s lifestyle, not on a one-size-fits-all calendar.
- Follow the interval stated on the product and treat all pets in the household at the same time.
- Never use a dog parasite product on a cat: some are toxic to cats.
- When worm risk is unknown, ESCCAP advises treatment or a faecal test at least 4 times a year.
Ticks do not take a winter break
According to ESCCAP, tick activity is seasonal but the season is long: in Italy and central Europe there are two peaks, one from March to June and one from August to November. In warmer climates some species, such as the brown dog tick Rhipicephalus sanguineus, can feed all year round and complete their life cycle indoors or in kennels; others, such as Dermacentor reticulatus, look for hosts even in midwinter.
A study carried out in Germany between 2020 and 2022 found ticks active in every month of the year: in winter 2020/21 a third of the ticks collected from dogs and cats were Ixodes ricinus, a species once thought to be rarely active in the cold. The authors recommend year-round control for pets with outdoor access. Ticks found on an animal should be removed as soon as possible with a purpose-designed tool, without oil, alcohol or ether.124
Fleas multiply indoors too
Adult fleas live on the animal, but eggs and larvae fall into the environment, especially where the pet rests. ESCCAP explains that in homes with central heating or carpets, development can continue regardless of the season: infestations peak in summer and autumn but can occur throughout the year.
Risk depends on lifestyle. For a cat that never goes outside, ESCCAP suggests regular coat checks with a flea comb and treatment only if fleas are found. For dogs and cats with regular outdoor access it advises ongoing prevention, together with daily vacuuming. In multi-pet homes, for hunting or breeding dogs, and for pets with flea allergy, it recommends continuous year-round protection.1
Intestinal worms: frequency depends on risk
ESCCAP worm guidelines recommend lifelong control, because few worm infections are strictly age-related. Frequency should be set with your veterinarian based on the individual animal: raw meat feeding, hunting, outdoor access, young children or vulnerable people at home. When risk is unknown, the general recommendation is to treat or test faeces at least four times a year: one or two treatments a year are not enough to prevent infections.
Some dog and cat worms, such as Toxocara, can also infect people, particularly children. Recommended measures include washing hands after handling pets and before eating, picking up faeces promptly and not composting them, grooming dogs regularly, washing raw fruit and vegetables, not feeding untreated raw meat and not letting pets drink from puddles. In areas where heartworm occurs, your veterinarian may advise specific prevention during mosquito season.3
How to use parasite products without mistakes
ESCCAP states that each pet should have a plan agreed between owner and veterinarian. How long protection lasts varies from product to product, and sometimes between tick species: the right interval is the one on the product leaflet, not “once a month” by default. Check your pet carefully towards the end of the protection period to spot whether the product is wearing off.
Common causes of failure listed by ESCCAP include not treating all household animals at the same time, wrong application or intervals, not realising that bathing and shampooing can reduce the efficacy of spot-on products, and overlooking places where fleas develop. Above all: some concentrated pyrethroids registered for dogs only are toxic to cats. Never use them on cats and, in homes with both dogs and cats, follow the label warnings carefully.13
Sources and checks
Numbers in the text lead to the exact source. Commercial blogs and social posts are not used as evidence.
- 1Veterinary guideline
ESCCAP Guideline 03: Control of Ectoparasites in Dogs and Cats (7th edition, 2022)
European Scientific Counsel Companion Animal Parasites (ESCCAP) · Tick and flea seasonality, indoor flea development, risk scenarios, causes of failure, toxicity of some pyrethroids to cats.
Link checked on 15 Sept 2026 - 2Veterinary guideline
Controllo degli ectoparassiti del cane e del gatto (linea guida ESCCAP n. 3, versione italiana)
ESCCAP · versione italiana · Two tick activity peaks in Italy (March–June, August–November); R. sanguineus present all year in southern Europe. 2012 edition.
Link checked on 15 Sept 2026 - 3Veterinary guideline
ESCCAP Guideline 01: Worm Control in Dogs and Cats (7th edition, 2025)
European Scientific Counsel Companion Animal Parasites (ESCCAP) · Lifelong control, individual risk assessment, at least 4 treatments or tests a year when risk is unknown, zoonosis prevention.
Link checked on 15 Sept 2026 - 4Peer-reviewed research article
Winter activity of questing ticks (Ixodes ricinus and Dermacentor reticulatus) in Germany — Evidence from quasi-natural tick plots, field studies and a tick submission study
Ticks and Tick-borne Diseases (2023) · PubMed PMID 37399628 · Tick activity in every month of the year and recommendation of year-round control for outdoor pets. Study partly industry-funded.
Link checked on 15 Sept 2026
This guide does not recommend products or doses. The choice of parasite product and treatment frequency should be decided with your veterinarian, based on your pet and where it lives.