Fleas are among the most important worldwide ectoparasites of dogs and cats. Besides being responsible for causing direct deleterious effects such as anaemia and dermatological problems, they are also responsible for the transmission of numerous pathogens, some of which are zoonotic [30]. In Portugal, flea-borne infections have been reported in both companion animals and humans [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28], highlighting the importance of public education regarding the measures to be taken to reduce the risk of exposure of dogs, cats, and humans to these ectoparasites and the pathogens they transmit. In the present study, a total of 550 companion animal owners in Mainland Portugal responded to a questionnaire regarding fleas, flea-borne pathogens, and their management: 38.5% were dog owners only, 28.7% were cat owners only, and 32.7% owned both animal species. Dog owners usually represent the largest percentage of participants in surveys conducted in the country [33, 34, 39], a trend that might be related to the fact that dogs are the most common pets in Portugal [9] and globally have greater access to veterinary care [41], which increases the frequency of interactions between dog owners and surveys.
Women made up 69.9% of the participants, which aligns with findings from previous studies on pet ownership, zoonoses, and parasite control awareness [35,36,37,38,39, 42]. This trend is likely related to a higher level of concern among women for the health and well-being of their pets. The mean age of pet owners who responded to the questionnaire was 40 years, and the majority had a secondary or higher level of education, which is similar to what was observed in other studies [35, 36, 38, 39]; this trend may reflect a greater interest among middle-aged adults and individuals with higher educational qualifications to participate in this kind of KP research studies. Geographically, the majority of participants were based in the Área Metropolitana de Lisboa (AML), whereas Algarve had the lowest response rate. Although the questionnaire was distributed through several veterinary clinics across Mainland Portugal, the number of participating clinics in the Algarve was relatively low, potentially influencing respondent numbers. This distribution pattern is consistent with previous national studies [34], [42] and may reflect regional variations in interest levels or cultural differences in pet care practices and perceptions.
Few studies have assessed companion animal owners’ level of knowledge regarding fleas and flea-borne pathogens [32, 35]. In a study from Hungary [32], most dog and cat owners were unaware that fleas can harm both animals and humans or that the environment can be a source of infestation, while in a study from Malaysia [35] about 40% of cat owners recognised fleas as pathogen vectors and were aware that infestations can originate from the environment. In addition, more than half of the Malaysian cat owners were also able to identify the size, food source, and movement of the fleas, which could be because most of the responders had previously experienced flea infestations in cats. In this study, over 70% of participants correctly identified the flea’s body colour and movement, while more than half recognised its size and diet, demonstrating a reasonable understanding of flea biology. Companion animal owners also recognised the environment, mainly outdoor spaces, and contact with infested animals as common sources of flea infestations, as well as the fact that fleas may remain active year-round, reflecting their awareness of the flea life cycle. Interestingly, cat-only owners were significantly more aware than the other two owner groups that fleas have a flat body shape, and that indoor environments and humans can also be a source of infestation. In contrast to previous studies [32, 35], most participants recognised fleas as vectors of pathogens affecting both animals and humans, with bites being the most commonly known transmission route. However, as in previous studies, only a few could name the specific etiological agents. Knowledge about pathogen transmission through scratches was significantly higher among cat-only owners. Although the identification of pathogens did not differ among the three groups, cat-only owners most frequently mentioned the etiological agents of cat-scratch disease and mycoplasmosis, while D. caninum was more frequently noted by dog-only and dog+cat owners, suggesting that some participants were able to correctly associate certain pathogens with the animal species they affect.
In this study, multivariate analysis confirmed trends observed in previous CPP questionnaires regarding sex, age, and education level. Specifically, a higher awareness of fleas and flea-borne pathogens was associated with participants who had higher education, were under 50 years of age (Kf only), and were female (Kp only). Knowledge was also higher among participants living in the AML, Centro, and Algarve regions. Interestingly, despite the low number of participants from the Algarve region, their greater knowledge may be linked to the participation of individuals particularly concerned about the seriousness of these ectoparasites.
The considerable ability of participants to recognise fleas, to associate flea presence with changes in animals’ behaviour, and to understand the role of these ectoparasites in pathogen transmission may be attributed to information provided by veterinarians or previous experiences with flea infestations in their companion animals. In fact, about two-thirds of the participants reported prior flea infestations, which may have prompted them to seek advice from veterinarians, the most common reported source of information on fleas and flea-borne pathogens, followed by social media and the internet. The acquisition of information about zoonotic infections from veterinarians emphasises their important role in raising the awareness of owners about the ways of transmission of the pathogens to their pets and themselves [35], although in some cases the proactivity of veterinarians in passing on knowledge has been considered negligible [36, 39]. Routine consultations provide an important opportunity for veterinarians to educate owners about the health risks fleas pose. To enhance the impact of these interactions, clear and simple educational materials, such as brochures, posters, and infographics, can be displayed in clinic waiting areas to reinforce key messages and support owner understanding. Curiously, and despite the fact that advertisements on TV about the application of ectoparasiticides to prevent arthropods and vector-borne infections was a common source of information identified in previous studies [36, 43], in the present study very few participants reported the use of this communication channel to obtain information about fleas and flea-borne pathogens. Similarly, the low demand for information on these topics from physicians (less than 10% of participants) suggests that healthcare professionals are not perceived as key sources of education on the risks of vector-borne zoonotic agents for pet-owning patients [44].
To effectively avoid and eliminate fleas, prevent flea-borne infections, and manage flea allergy dermatitis, an integrated control strategy should target both immature and adult flea stages. This strategy may involve using products containing insect growth regulators or juvenile hormone analogues, formulations with repellent or fast-killing properties, or those with combined effects on both the animal and its environment. To prevent and eliminate infestations, a range of products are available in various formulations, including collars, spot-on treatments, sprays, powders, shampoos, chewable or hard tablets, and injectables [30, 45].
ESCCAP recommends year-round flea prevention to cover the complete activity period of the ectoparasite, as exposure is difficult to avoid [31].
Portugal has a temperate Mediterranean climate [46], which likely creates favourable conditions for flea populations to persist throughout the year. This climate, characterized by mild winters and warm to hot summers, combined with the common outdoor access granted to pets, increases the risk of flea infestation and underscores the need for continuous preventive measures. Most participants stated that their companion animals were treated against fleas as a preventive measure, aligning with previous studies on ectoparasite control practices among dog and cat owners [33, 34, 39, 47]. About half of the participants treated their pets for ectoparasites every 3 to 4 months, followed by every 6 to 8 months, and once per month. The preference for spot-on treatments among cat owners aligns with other studies, likely due to their ease of application [47]. Similarly, oral tablets were less commonly referred to as being used by this group, probably because cats are considered to be difficult to medicate orally [47]. As the questionnaire did not include the active ingredient of the products used, the accuracy of their application according to the manufacturer’s recommendations cannot be assessed. Given that spot-on treatments were the most commonly used route among cat-only owners and owners of both animal species, and with few exceptions are effective for only 3–4 weeks, it is likely that many pets were not treated at the correct frequency. The same conclusion can be drawn for the administration of ectoparasites in tablet form, the second most commonly used product by dog owners and owners of both animal species, since the treatment schedule is between 4 and 12 weeks. Reasons for non-compliance may relate to a lack of awareness about the importance of continuous prevention, the absence of infestation (thus reducing adherence to long-term prevention protocols), or financial constraints, with the latter reported by 15.4% of participants. Flea treatment rates for all animals in the household were significantly lower among dog and cat owners than among those who owned only dogs or only cats, although the overall frequency of flea treatment did not differ significantly between these groups. A survey of dog owners in Thailand found that the cost of flea and tick prevention, especially in households with multiple dogs, was linked to less frequent use of preventive treatments. Most owners tended to use products only when their dogs were infested [37]. In the present study, only a small percentage of participants claimed to treat their animals only when fleas were detected.
Effective prophylactic treatment should be used in conjunction with environmental control to target all life stages. Mechanical environmental measures such as frequent vacuuming, washing pet bedding, and cleaning all areas that may harbour eggs can significantly reduce the household flea burden [6, 32, 50]. Interestingly, cleaning, vacuuming, and applying insecticides to the house and the animal’s resting places, along with brushing the animal, were the most frequently mentioned measures for controlling infestation, suggesting that many owners are aware of the importance of these practices in managing flea infestations. Cat-only owners were significantly more likely to choose the practice of cleaning areas with a possible higher risk of infestation and presented greater willingness to ask veterinarians for advice on preventing and controlling fleas. This, together with their greater knowledge of flea morphology and the fact that indoor environments and humans can also be sources of infestation, indicates a previous history of contact with fleas. In fact, 53.2% of the respondents of this group reported prior experience with fleas, which likely explains a greater motivation to apply preventative measures. Interestingly, a significantly higher proportion of participants in this group reported keeping their animals indoors from sunset to sunrise as a control measure. This may reflect confusion with other insects active during that time, such as mosquitoes and phlebotomine sand flies.
As mentioned earlier, multivariate analysis indicated that higher education was associated with greater knowledge of fleas and flea-borne pathogens. However, this knowledge did not lead to a higher adoption of protective practices. This discrepancy could be related to the perception that general protective measures against arthropods and arthropod-borne infections are also effective against fleas, suggesting that specific flea control measures may be unnecessary.
Conversely, higher practice scores were observed in owners under 60 years old, those living in the AML or Centro regions, and those owning only cats or only dogs. This may reflect a greater concern for preventive measures among middle-aged participants and individuals with higher knowledge of fleas and flea-borne pathogens. Additionally, owning a single species might lead to more focused and effective infestation prevention strategies.
Although over 30% of Portuguese households owned at least one dog or cat in 2022, respondents in this study came from only 86 of the 278 municipalities in Mainland Portugal. This limited geographical representation may have hindered a detailed analysis of how sociodemographic differences influence knowledge about fleas, the diseases they can cause, and management measures for these ectoparasites. As a result, the study’s ability to accurately identify trends in pet owners’ KP may have been affected. Future research should address this limitation by ensuring broader geographical representation, thereby strengthening the reliability of the findings.
Another limitation was the absence of including the residence of companion animal owners, as animals living in rural areas are more exposed to fleas, which may influence the awareness of the owners regarding these ectoparasites and their management.
