Dog Owners' Awareness of the Zoonotic Potential of Endoparasites of their Pets and Potential Risk Factors for Humans

Marko Ristić¹Aleksandar Višnjić^2,3*

• ¹University of Niš, Faculty of Agriculture Kruševac, Niš, Serbia
• ²Faculty of Medicine, University of Niš, Niš, Serbia
• ³University of Niš, Faculty of Medicine, Niš, Serbia

Modern medical science views health as a dynamic balance within the systems of the human organism and the environment. The concept of prevention is based on preserving a balance of a healthy individual in a secure environment (1,2).Public areas contaminated with geohelminths from dog faeces pose a risk to human health, especially in cities where parks, children's playgrounds and sand pits can be a source of oral or percutaneous infection for humans. Although they have exceptional clinical and epidemiological importance, the importance of these pathogens is very often minimized by doctors of veterinary medicine, physicians and the general public (3). Ten endoparasites (six at the species level and four at the genus level) were diagnosed in dog feces, soil and sand samples in the three main approached parks of the city of Nish in our previous research: protozoas of the specius Cystoisospora, nematodes (Toxocara canis, Toxascaris leonina, Ancylostoma caninum/Uncinaria stenocephala, Trichuris vulpis, Capillaria aerophila), trematoda Alaria alata and cestode (Dipyllidium caninum, Taenia spp) (1,4).For the majority of zoonotic parasites diagnosed in the three most visited public parks of the city of Niš in 2024, humans are a non-specific host. The biggest problem for doctors in differential diagnostics includes T. canis, C. aerophila, and A. alata, whose encysted larvae in the liver, lungs, kidneys, heart, and lymph nodes can calcify, necrotize, or degenerate, thus causing confusion even for the most experienced diagnosticians. Insufficient education about what to expect etiologically can result in serious errors in establishing a valid diagnosis (4,5).As reservoirs of infection, the greatest danger to human health involves stray dogs, which move freely and uncontrollably in city parks. Therefore, a long-term solution to this problem is necessary by adopting a strategy to regulate the number of abandoned dogs (5), with mandatory parasitological control of public areas and an appropriate social-medical approach to solving this current health and environmental problem in urban areas.Since humans and dogs share living space and have very close contact, and since the basic assumption is that many owners do not take adequate care of their pets, there is a possibility of transmission of parasitic diseases from dogs to humans. Therefore, it is necessary to raise public awareness about the necessity of implementing zoohygiene measures in dog breeding and the importance of causal planned deworming and anti-ectoparasite treatment. In addition, our goal would be also to start drawing up a Program of Health and Educational Measures to reduce the risk of human illnesses with zoonotic parasites from dog faeces in the public areas.The study represents a social-medical approach to the problem of contamination of public urban areas in the City of Niš with intestinal parasites from dog faeces. Accordingly, a survey was conducted on attitudes, behaviour and the level of education of dog owners and people staying in the parks of the city of Niš. The interview with people was carried out in three city parks during the months of February, March and April 2024.A total of 350 dog owners were surveyed -198 (56.57%) of them were female, and 152 were male (43.43%). In "Park Chair" there were examined 123 of them; 117 were interviewed in "Sveti Sava Park", while the remaining 110 respondents were interviewed in "Tvrđava Park". The research was conducted in concordance with the Declaration of Helsinki. All participants were informed about the study and they provided informed consent.In order to examine citizens' knowledge, attitudes and behaviour, a modified questionnaire was used for people who often visit parks (6)(7)(8).Survey method. People were surveyed in those three parks mentioned by employing the interview method. The sample was selected by the method of random selection. It was conducted with randomly selected respondents. It is important to emphasize that none of them asked to participate refused to answer the offered questions from the survey.In addition to socio-demographic characteristics, the questions refer to data on attitudes, behaviour and the level of education, as well as to the ownership of pets and possible risk factors for infection with zoonotic parasites.-Do they conduct regular coprological examinations of their dogs 4 times a year? The null hypothesis was tested with a significance threshold of p<0.05. The data were processed in the SPSS 18.0 software package (SPSS Inc., Chicago, IL, USA).A total of 350 dog owners were surveyed. 198 (56.57%) of them were female, and 152were male (43.43%) (Table 1).The average age of the respondents is 45.8±11.5 years. A slightly larger number of surveyed owners live in an apartment -52.86% (185/350), while 47.14% (165/350) live in a house. There are 108 respondents (30.86%) who have higher education (Table 1). Almost half of the dogs (48%) were acquired by their owners from kennels (i.e. dog breeders), 25% from friends, 13% from shelters, while 14% of the dogs were from the street.Dog owners have had their dogs for 7.8±2.5 years, on average.There were more females among the dogs, 52.86% (185/350), compared to males, 47.14% (165/350), with an average age of 6.5±3.2 years and the youngest dog being one year old and the oldest sixteen years old. The majority of dogs were canine-certified -70%(245/350). In terms of sterilization, a significantly higher number of females than males were sterilized (χ 2 =22.58; p<0.001). The largest number of respondents take their dog to a veterinarian when they have doubts about their dog's health (22.3%), 9.4% of respondents every 6-12 months, 56.3% of interviewed owners do not take their dogs to a veterinarian, and 12% every 1-3 months (Table 2). The most common reason for visiting a veterinary doctor is vaccination.The largest number of owners give tablets against internal parasites every six months (29%), 22% of owners every 3 months, and 21% of owners once a year. The greatest number of owners treat their dogs against fleas and other external parasites every 6 months (22%), while 21% of owners do so once a year (Table 2).One third of dog owners have their dogs vaccinated against infectious diseases each year (Table 2). The situation is slightly different with rabies vaccination, with a half of all dog owners surveyed getting it done every year. The largest number of interviewees (62%) travel with their dogs, a half of them even sleep with their pets, and a third of them take their dogs to the pet groomer.Regular coprological examinations of dogs are carried out by only a fifth of the surveyed owners, while 35% of them follow recommendations of veterinary doctors for the use of anthelmintics as a part of preparing the dog for vaccination, and only 19% of dog owners remove their pets' faeces from public areas (Table 2). More than a half of the interviewed dog owners regularly use both anti-endoparasitics and anti-ectoparasitics to treat their dogs.By comparing the characteristics of the surveyed groups of dog owners in relation to gender, age and educational profile, it has been determined that the distribution by gender was homogeneous (χ 2 =0.132; p=0.732). No statistically significant difference has been found in the place of residence (χ 2 =3.158; p=0.078), nor in the educational status between the studied groups (χ 2 =0.303; p=0.862). Women are more likely to take their dogs to dog shows (σ=-0.185; p=0.022) and more likely to remove dog faeces from public areas (σ=-0.253; p=0.002) (Table 3).In addition, women more often touch abandoned stray dogs and have contact with them (χ 2 =5.783; p=0.015) and very often visit friends who keep dogs (χ 2 =13.282; p=0.001). Older owners have owned their dogs for a longer period of time (σ=0.167; p=0.044), but they give tablets against internal parasites (σ =0.267; p=0.001) and external parasites (σ =0.177; p=0.032) to their dogs less often (Table 4).Younger dog owners are more likely to have their dogs vaccinated against infectious diseases (σ = -0.335; p<0.001) and rabies (σ =-246; p=0.002), more likely to take their dogs to dog shows (σ =-0.292; p<0.001), more likely to travel with their dogs (σ =-0.372; p<0.001) and more likely to remove faeces from public areas (σ =-0.311; p=0.002) (Table 4). Owners with higher educational status are more likely to take their dogs to a veterinarian (σ=0.315; p<0.001), more likely to treat their dogs against fleas and other external parasites (σ= -0.212; p=0.008), more likely to have their dogs vaccinated against infectious diseases (σ=0.298; p<0.001) and rabies (σ=0.247; p<0.002), and more likely to remove faeces from public areas (σ=0.308; p<0.001) (Table 5).A variety of recent studies have shown that the contamination of public areas with parasite eggs is common across the world (3)(4)(5)(6)(7)(8)(9). The level of contamination in Serbia is shown to be similar to other compared countries (1,2).Actually, the presence of a large number of zoonotic agents in the examined samples is conditioned by daily contact between owners' dogs (dogs kept in apartments and yards) and stray dogs in the territory of public city parks, which further increases the risk to human health (1)(2)(3)(4). Urbanization of cities leads to the expansion of the urban belt to peripheral parts of the city and weekend settlements where only foxes lived until recently. With the expansion of cities, stray dogs and owners' dogs come into close contact with foxes, which causes a significant change in the parasitofauna of dogs, which dogs eliminate through faeces on public surfaces and represent a source of infection for human beings (3).Based on the data from the obtained results, a half of the owners acquired a dog from kennels. Due to the fact that dog breeders are often the first line of information for future owners about dog deworming, all people who are professionally engaged in dog breeding should have the right attitude about dog deworming treatments. Through the research results, it can be noticed that the respondents are not adequately or at all familiar with diseases of parasitic etiology. Dogs staying at the shelter should also be adequately treated with antiparasitics, and future owners who take these dogs should receive recommendations on planned deworming.The highest risk comes from future owners who buy or get a dog from a friend because in this case their choice is related to a person who is actually their role model, which is why they decide to buy or take a dog from him/her. Our findings are very similar to recent researches on this topic in other countries as well (9)(10)(11). If the owner who provides the puppy has a bad attitude, i.e. is inadequately informed about deworming, new owners cannot be expected to carry out the treatments against parasites correctly and continuously (12)(13)(14)(15). It is also considered that those people who live in an apartment with a dog are more at risk, because they have closer contact with the pet, compared to the owners whose pets stay in the yard (16)(17)(18).The research results indicate that owners take their dogs to the veterinarian mostly when they have doubts about their health, which is not good for the pet at all. Considering that the owners are not able to recognize real symptoms of the disease and that very often their pet is taken care of by other family members, their understanding and assessments of the pet's symptomatology and health condition are debatable. Moreover, their assessments are mostly subjective in nature and differ from each other. In a large number of families, there is poor communication between individual members, which additionally causes a poor or unsatisfactory exchange of information about the pet and its health condition (19,20).The majority of owners answered that every 6 months they treat the dog against fleas and other external parasites. If there is cohabitation with a cat in the apartment, an additional problem is the danger of another pet suffering from flea infestation. Owners are not aware that the number of several fleas they have observed on the dog is not a real number, but indicates the presence of a significantly larger number of these ectoparasites (21)(22)(23)(24). Dogs that undergo grooming treatments are certainly also treated against ectoparasites, because groomers do it or inform the owners if they see fleas. Some owners take their dogs for a haircut precisely because of the presence of fleas or ticks (25,26). Owners who share a bed with their dogs are the most vulnerable group of dog owners. In this case, dogs literally leave developing forms of parasites in the bedding, some of which can even be inhaled into the organism of the owner.Slightly less than a half of the surveyed dog owners indicated that they share information about parasitic diseases with other owners (27,28). However, regardless of the level of their education, or the level of commitment to their pets, one gets the impression that the owners' awareness of parasites is still at a minimum, as a result of lack of information. In support of this claim is the fact that the dog is usually taken care of and fed by a large number of people from the family, who do not exchange information about the dog, nor do they try to upgrade their knowledge regarding certain health problems of their pet and the risks that such conditions carry with them (29,30).It has been found out from the research results that the majority of owners randomly treat their pets, without a previous parasitological examination, preventively against parasites by choosing the wrong antiparasitic. In order to avoid the problem of developing resistance to anthelmintics, which is caused by the owner's mistakes in the therapy and prophylaxis of parasitosis of pets, it is necessary to carry out regular coprological examinations immediately after acquiring the dog and during their stay with the owner.