Summary: Respiratory capillariosis is a widely distributed zoonotic parasitic disease caused by the nematodeCapillaria aerophila(Trichocephalida, Trichuridae) that commonly infects wild carnivores but also cats and dogs. This retrospective study aims to describe cases of respiratory capillariosis in cats from the city of Belgrade, Serbia. Between 2015 and 2019, a total of 155 pet cats with or without respiratory symptoms were submitted to physical examination and parasitological examination of the feces. All cats lived indoor but had free access to outdoor. In suburban settlements, wild carnivores commonly share their living environments with owned cats and dogs. It can be assumed that more intense urbanization spreading into the natural habitats of will carnivores creates the opportunity for closer and more frequent contacts between the population of cats and feral carnivores which might increase the risk of feline contamination. The findings confirm the existence of capillaries in cats in urban areas of the city of Belgrade, contribute to a better understanding of the epidemiology of this nematode and warn that, because of close contacts between cats of pets and humans, capillaries can cause human infection.

Acanthocheilonema (Dipetalonema) reconditum is a less pathogenic species of filaria from the superfamily Filarioidea, and which parasitizes in the subcutaneous connective tissue of dogs, hyenas and jackals. The results of epidemiological studies indicate the zoonotic potential of A. reconditum, bearing in mind it can cause infections with clinical disorders in humans. This filaria is spread globally and it is mostly described in geographical areas such as the Mediterranean Basin, the Middle East, South Africa, South America and Oceania, where it is the only or is the most common filaria that infects dogs. The prevalence and distribution of A. reconditum depend mainly on the vector population, impact of environmental factors, and lifestyle of pets and their owners. Apart from the standard parasitological techniques for differential diagnostics of filariae, more attention is being dedicated to the development of protocols that are based on the simultaneous detection of specific DNA regions in each type of individual filaria. Due to its importance for public health, effective vector control is required, as well as regular preventive examinations, reliable diagnostics and therapy for A. reconditum in dogs, and continuous cooperation between veterinary and medical surgeons.

Canine filariosis is an emerging vector-borne parasitic disease of veterinary and public health importance, caused primarily by D. immitis and D. repens. The present study investigated the prevalence, risk factors, diagnostic performance of different methods, and molecular characteristics of filarial infections in dogs from the Republic of Srpska (Bosnia and Herzegovina). Blood samples from 418 dogs collected between 2020 and 2024 were examined using a modified Knott test, antigen enzyme-linked immunosorbent assay, and polymerase chain reaction-based methods. Overall, 21.3% of dogs were positive for at least one filarial species. D. repens was the most prevalent species (13.40%), followed by D. immitis (10.8%) and A. reconditum (1.4%). Coinfections with D. immitis and D. repens were detected in 3.35% of dogs, while triple infections occurred in 0.5%. Several individual and environmental factors were associated with an increased risk of infection, including poor body condition, mixed-breed status, inadequate parasite control, and specific movement histories. PCR showed the highest diagnostic performance for all detected species, outperforming both microscopy and antigen testing. Phylogenetic analysis revealed genetic diversity among the detected isolates and demonstrated their relationship to strains previously reported from other European countries. These findings confirm the endemic presence of canine filarial infections in the Republic of Srpska and emphasize the importance of molecular diagnostics, surveillance programs, and preventive measures for effective disease control.

Pearsonema plica is a nematode commonly found in wild carnivores and occasionally in domestic dogs, where infections are often overlooked. This cross-sectional study investigated its prevalence in 88 hunting dogs from five districts in Serbia between October 2021 and May 2024. Urine samples were examined via light microscopy, and molecular analyses (PCR and sequencing of the 18S rRNA gene). Presence of P. plica eggs was found in 20.45% of the tested dogs. Phylogenetic analysis clustered the obtained isolates with reference sequences of P. plica. Hunting activity within two months prior to sampling and irregular or infrequent deworming were significantly associated with higher infection rates. Dogs showing urinary symptoms were more likely to test positive. This study provides the first molecularly confirmed data on P. plica infection in hunting dogs in Serbia and indicates that urinary capillariosis in dogs and the need for greater clinical awareness. However, due to the limited sample size and potential sampling bias, the results should be interpreted with caution. Further large-scale and longitudinal studies are needed to better understand the epidemiology and clinical relevance of this infection in domestic dogs.