The occurrence and prevalence of parasites in dogs can be influenced by many factors. Toxocarosis (T. canis) occurs especially in young dogs. In our group of 391 coprological examined individuals, 9.3% of dogs less than 1 year, 4.3% of dogs aged 1–7 years and 1.9% of dogs over 7 years were infected with this parasite. Dangerous accumulation of Toxocara eggs occurs even during limited excretion because these are extremely resistant and survive in the environment for a long time. Environmental contamination and transmission of T. canis eggs to humans is an internationally known epidemiological risk . Informing and educating dog owners through veterinarians play a key role in reduction the amount of T. canis eggs in the environment . We cannot leave out the risk of resistance to pyrantel in ascarids and hookworm in dogs and cats [27, 28]. Although mono-component VMPs are used less commonly (6.7%) due to using of pyrantel embonate in 69.8% cases from using of mono-component VMPs the responsible vet should give recommendations on how to limit further selection for resistance to anthelmintics. We confirmed Giardia spp. cysts only in dogs less than 1 year, the percentage reached to 1.9%. Zoonotic potential of Giardia is limited, but confirmed transmission of specific assemblage C from dog to human indicates a risk for immunodeficiency patients . Using molecular biological methods we have focused on dangerous zoonotic tapeworms. Echinococcus multilocularis eggs were not found in any of the investigated dogs, nevertheless, it is necessary to familiarize owners through veterinarians with the need for prevention, especially in dogs with the possibility of hunting rodents. The finding of the second zoonotic tapeworm Taenia crassiceps was surprising and alarming. Taeniid eggs were detected by PCR in 4 dogs, in one of them eggs were revealed microscopically by flotation. T. crassiceps was confirmed by PCR in three dogs, 12 years, 3 years and 7 months of age. The dogs, 12 years and 3 years, lived in the house with the possibility of walks. Dog owners reported frequent running away without control with the possibility of predation. The dogs were dewormed twice and four times a year, respectively, with VMP containing combination of praziquantel, pyrantel and febantel or fenbendazole. Seven months old dog was kept freely in the garden and treated five times in one-month interval. However, a non-tapeworm product (selamectin) was used for the last treatment. The confirmed occurrence of T. crassiceps alerts to choice suitable VMP and using coprological examination regularly.
Excreted eggs of T. crassiceps may cause cysticercosis, especially in individuals with weakened immunity, and endanger the health of not only animals but also humans [23, 29]. For this reason the owners could underestimate risk of zoonosis and the risk of parasitosis should be suppressed by regular laboratory tests and corresponding therapy. Fast screening test of taeniid eggs could be great benefit for veterinary practice because they could stop shedding of danger eggs.
The parasites pathogenic for dogs without zoonotic potential were also diagnosed in investigated dogs. Lungworms Angiostrongylus vasorum (1.7%) and Crenosoma vulpis (0.9%) were detected by larvoscopy testing, similar results were obtained in 2017 . As lungworms in the dogs were rarely identified in the Czech Republic in the past, disease awareness of lungworms among animal owners and veterinarians should be implemented . Based on the investigated group of individuals, the vast majority of dogs may occasionally become infected during a walk. The responses of owners show that the frequency of administration of endoparasitics is chosen randomly regardless of way of life, usually one to four times a year, most often 1–2 times a year. Frequency of administration does not take into account any risk factors, whether dog age or the possibility of rodent hunting and free movement in nature, which significantly increase the risk of infection. By questionnaire action in Germany, frequency of dogs deworming was found 2.07 times a year although questionnaire responses showed that 62% of the animals were at risk for their age and behaviour. For this risk group, it is recommended to perform a coprological examination or to administer an anthelmintic at monthly intervals according to ESCCAP (European Scientific Counsel Companion Animal Parasites) . Proper choice of antiparasitic and appropriate frequency of its administration is essential to prevent excretion of parasite eggs and contamination of the environment with them. Wide range of freely accessible antiparasitic veterinary medicinal products is available without a prescription to be gained and used by dog´s owner. However, intended effect will not occur if veterinary medicinal products are used without consulting the veterinarian, i.e. without adequate knowledge when owners did not have a respect to criteria for deworming age of dogs or type of breeding including possibility of predation. Stipulating certain VMPs as prescription only, is one of the National Agency risk management tools influencing the handling of VMPs in practice.
As for the results presented, actual prevalence of endoparasitosis of dogs will be probably higher considering that we have possibility to examine one sample of faeces per dog only. It should be noted that dogs studied belong to owners that are more likely to co-operate with vets.
In the Czech Republic, consumption of VMPs with antiparasitic active substances is monitored similarly as in other EU countries by the National Agency, the Institute for State Control of Veterinary Biologicals and Medicines, as listed below.
Between the years 2015 and 2018 in the Czech Republic, 3,267,186 to 4,699,352 therapeutically doses of antiparasitics were used for treatment of dogs. Most frequently, VMPs were administered in the pharmaceutical form as tablet; approximately 2,898,493 to 4,395,305 doses of endoparasitics were used and approximately 2,763 to 25,149 doses of endectoparasitics. Pharmaceutical form as oral paste, suspension or gel was used in 147,038 to 237,210 therapeutically doses. Endectoparasitic in pharmaceutical form as spot-on was administered to 53,368 to 100,373 therapeutically doses. In terms of the reported total consumption of antiparasitics for dogs in the Czech Republic, the proportion of the pharmaceutical forms corresponds to the pharmaceutical forms in the monitored group, similarly rate of the consumption of combined VMPs to the consumption of mono-component VMPs. Various combinations of active substance as praziquantel with pyrantel embonate, fenbendazole, febantel, oxantel, emodepside or milbemycin-oxime were administered orally in tablets to approximately 2,766,649–4,380,478 therapeutical doses, of which the combination of praziquantel with pyrantel embonate and fenbendazole or febantel was administrated to 182,853–3,668,126 therapeutical doses.