First report of Eucoleus boehmi infection in a dog from Portugal

Integrated Taxonomic Approaches to Gastrointestinal and Urinary Capillariid Nematodes from Wild and Domestic Mammals

Fine nematodes of the family Capillariidae parasitize various organs and tissues in fish, amphibians, reptiles, avians, and mammals. Currently classified into more than 20 genera, these nematodes are primarily distinguished based on the caudal structures of male worms. Morphological and molecular analyses were conducted on 15 mammal-parasitic species belonging to the genera Aonchotheca (A. putorii, A. suzukii n. sp., A. suis n. comb. (syn. Capillaria suis), A. riukiuensis, and A. bilobata), Pearsonema (P. neoplica n. sp., P. feliscati, P. iharai n. sp., and P. toriii n. sp.), Liniscus (L. himizu), Calodium (C. hepaticum), Echinocoleus (E. yokoyamae n. sp.), and Eucoleus (E. kaneshiroi n. sp., E. aerophilus, and Eucoleus sp.), using specimens from various wild and domestic animals in Japan and brown rats in Indonesia. As demonstrated in this study, nearly complete SSU rDNA sequencing is a powerful tool for differentiating closely related species and clarifying the phylogenetic relationships among morphologically similar capillariid worms. Additionally, most capillariid worms detected in dogs and cats are suspected to be shared with their respective wildlife reservoir mammals. Therefore, molecular characterization, combined with the microscopic observation of these parasites in wildlife mammals, provides a robust framework for accurate species identification, reliable classification, and epidemiological assessment.

Prevalence of Capillaria spp. and other endoparasites of hunting dogs from southern Italy

Gastrointestinal and cardiopulmonary nematodes are frequently detected in dogs worldwide, posing a potential zoonotic risk. Some parasites, such as Capillaria aerophila and Capillaria boehmi, are often less considered being misdiagnosed with other trichurids. Here, we evaluated the occurrence of Capillaria spp. as well as of other endoparasites in hunting dogs from Basilicata region, Southern Italy. Individual faecal samples were collected from hunting dogs (n = 443) and examined by Mini-FLOTAC® flotation method. Additionally, 49 of the above samples were evaluated by the Baermann-Wetzel technique, and 90 sera samples were subjected to the Angio Detect™ test (IDEXX Laboratories Inc., Westbrook, Maine, USA). Out of 443 faecal samples, 251 (i.e., 56.6 %) scored positive for at least one parasite species, with hookworms being the most prevalent nematodes (i.e., 39.3 %), followed by C. aerophila (i.e., 20.5 %), Trichuris vulpis (i.e., 12.6 %) and Toxocara canis (i.e., 11.3 %). At the Baermann-Wetzel technique, 8.2 % (n = 4/49) of the faecal samples scored positive for Angiostrongylus vasorum, 4.1 % for Ancylostomatidae (n = 2/49) and 2.0 % for Strongyloides spp. (n = 1/49). A single serum sample scored positive for A. vasorum at the Angio Detect™ test. The results indicate that hunting dogs may harbour a high diversity of endoparasites, including those of zoonotic concern. Moreover, it is hypothesized that the occurrence of C. aerophila and C. boehmi may compromise the overall hunting performance due to the respiratory distress and impairment of scenting abilities. Therefore, control measures should be implemented to protect both dogs as well as humans living in close contact with them.

Eucoleus aerophilus (syn. Capillaria aerophila) infection in zoo-housed arctic foxes (Vulpes lagopus)

PURPOSE

Eucoleus aerophilus (syn. Capillaria aerophila) (Nematoda: Capillariidae) is a common endoparasite of free-ranging canids. In zoological gardens, reports on E. aerophilus-infections are scarce. We here present a case series of E. aerophilus infections in zoo-held arctic foxes with the aim to provide assistance for zoo veterinarians for future cases.

METHODS

A total of five zoo-born and -housed arctic foxes (Vulpes lagopus) were presented with coughing periods and strong phlegm, four of them showing rapid deteriorations at different time points including dyspnoea leading to death. Coproscopical analysis of pooled and individual faecal samples and necropsies were performed.

RESULTS

Faecal analysis showed shedding of typical capillariid eggs, which corroborated the suspicion of respiratory capillariosis. Multiple attempts of deworming using different anthelmintic treatment protocols (fenbendazole; milbemycinoxime and praziquantel; ivermectin; levamisole; selamectin; moxidectin and imidacloprid) did neither result in negative egg shedding periods nor in improvement of clinical symptoms. A regime performed with fenbendazole (100 mg/kg bodyweight per os over 14 days) resulted in cessation of egg shedding. At necropsy of four animals, multifocal chronical granulomatous pneumonia was diagnosed, associated with a massive infection with adult nematodes detected in trachea, bronchi and bronchioles and bacterial infections. Morphological analysis of extracted nematodes identified E. aerophilus, which was confirmed by molecular analysis based on the 18S rRNA gene.

CONCLUSION

We here show clinical and necropsy data and morphological and molecular worm identifications and call for further parasitological research in ex situ populations of arctic foxes to assess the impact of parasites on this species.

A case of a dog refractory to different treatments for pulmonary capillariasis

Pulmonary capillariasis is a parasitic disease caused by the nematode Eucoleus aerophilus which affects wild and domestic carnivores. Currently, there are no anthelmintics approved for use in the treatment of dogs infected with E. aerophilus. The use of several anthelmintics has been reported in a few case reports and field efficacy studies in cats; much less is known on the treatment of dogs infected with E. aerophilus. The paper describes a case of a 4-month-old, mixed breed intact male referred to the Veterinary Teaching Hospital (VTH) of the Department of Veterinary Medical Science of the University of Bologna for a routine vaccination and tested positive for E. aerophilus. The dog has not been responding to three different administered treatments, such as moxidectin, fenbendazole, and milbemycin oxime. Eighteen months after the first fecal examination, owner has brought in the dog for a routine visit; a coprological examination was requested and performed resulting negative for parasites. Veterinary practitioners, parasitologists, diagnostic laboratories, and dog owners need to be aware of the increased danger of possible treatment failure when attempting to control parasitic infections for which there are no approved anthelmintics with established efficacies available for use.

Capillaria boehmi (syn. Eucoleus boehmi): Challenging treatment of a rarely diagnosed nasal nematode in dogs and high prevalence in Swiss foxes

Despite morphological differences of eggs and adults, Capillaria boehmi infections have been occasionally misdiagnosed as C. aerophila infections in the past. Capillaria boehmi is found in the nasal and paranasal sinuses of wild canids and dogs, which may suffer from nasal discharge, sneezing, epistaxis and, importantly, their scent can be impaired. In this study we present three challenging cases of nasal capillariosis in dogs, report and review the variable success of anthelmintic treatments and investigate C. boehmi prevalence in Swiss red foxes, considered as potential wild life reservoir. Out of two females and one male dog (all scent hounds, aged 3-9 years and weighing 19-31 kg), two dogs were previously coproscopically misdiagnosed with Trichuris infections. Two dogs showed clinical signs such as sneezing, coughing and impaired scent. From one dog adult living C. boehmi were obtained by nasal lavage. The identity of worms and eggs of all three dogs were genetically confirmed (18S rRNA, 100 % identity in 578 base pairs). Dogs 1-3 were followed-up for overall 54, 8, and 67 months, respectively. All dogs repeatedly excreted C. boehmi eggs in faecal samples despite treatments with the following compounds, in various dosage and retreatment protocols: fenbendazole, milbemycin oxime (orally), moxidectin/imidacloprid/ (spot-on) and levamisole (intramuscularly). The different anthelmintic compounds showed variable success regarding their effect on clinical outcome and on stopping egg excretion. Reinfections due to a contaminated environment could not be fully excluded. In winter 2016 and 2017, 218 foxes from the canton of Zurich, Switzerland, were examined. Tissues of nasal and paranasal sinuses were investigated for adult Capillaria specimens and eggs. We describe for the first time C. boehmi infections in Switzerland, observing a high prevalence (190/218, 87.2 %). Overall, 107 of 126 adults (84.9 %, 95 % Confidence Interval, CI: 77.5-90.7 %) and 83 of 92 youngsters (90.2 %, CI: 82.2-95.4 %) were infected. The presence of C. boehmi did not correlate with age (P = 0.209), but correlated significantly with sex: male foxes (102 of 107, 95.3 %, CI: 89.4-98.5 %) were significantly (P = 0.001) more often infected than females (88 of 111, 79.3 %, CI: 70.5-86.4 %). Worm burden ranged from 1 to 72 adult specimens (geometric mean: 5.7). In conclusion, C. boehmi infections can be mis- and/or underdiagnosed in dogs. Appropriate anthelmintic treatments, preventing coprophagia and egg contamination of the surroundings and performing coproscopic controls after treatments are fundamental aspects. Potentially, nasal washing may represent an auxiliary alternative. However, the successful elimination of C. boehmi infections in dogs remains challenging.

First morphological and molecular analysis of Eucoleus boehmi like eggs in dogs from Argentina

The canid parasites Eucoleus aerophilus (syn. Capillaria aerophila) and Eucoleus boehmi (syn. Capillaria boehmi) parasitize the lower and the upper respiratory tract, respectively. Reports and descriptions of these nematodes are scarce in Argentina, possibly due to misdiagnosis of morphologically similar trichuroids eggs, and the lack of knowledge about the species of Eucoleus in this geographical area. Scanning electron microscopy is a useful tool for identification of E. boehmi eggs based on the characteristics of the shell structure which differentiate between species. Molecular analysis complements morphological identification. Until now, there are no studies based on the analysis of E. boehmi eggs in Argentina. The aim of the present work was to study by morphological, morphometric, and molecular analysis, eggs attributable to E. boehmi isolated from dogs naturally infected in Mar del Plata city, Argentina. Eggs isolated from two dog fecal samples were analyzed by light and scanning electron microscopy. A fragment of mitochondrial DNA (mtDNA) of the cytochrome c oxidase subunit I gene (cox1) from eggs was sequenced, and phylogenetic analysis was performed in this study. According to morphological results based on the wall surface ultrastructure, the eggs studied were assigned to E. boehmi. Molecular analysis supported the morphological identification. The divergence of 9-12% with the European isolated could suggest a new geographical genetic variation of E. boehmi, but also question the possible existence of cryptic species. This is the first characterization of E. boehmi eggs in dogs from Argentina.

High prevalence of Eucoleus boehmi (syn. Capillaria boehmi) in foxes from western Austria

Eucoleus boehmi (syn. Capillaria boehmi) is a canine trichuroid nematode affecting the upper respiratory airways (i.e., nasal cavity and paranasal sinuses) of dogs, foxes, and wolves. In the past few years, reports in dogs and wild canids have increased from across Europe, but data on its occurrence and distribution in Austria is scanty. A total of 47 red foxes (Vulpes vulpes) from the two westernmost provinces (Tyrol and Vorarlberg) of Austria were therefore examined for the presence of E. boehmi at necropsy. Eggs and adult nematodes were identified morphologically and molecularly (cox1) as E. boehmi. These nematodes were found in 26 (78.8 %) and 13 (92.9 %) foxes from Tyrol and Vorarlberg, respectively, with an overall prevalence of 83.0 % (39/47). The prevalence rate of infection recorded in this study is among the highest in Europe. These results suggest that foxes may represent an important source of infection for dogs and other canids, but further studies are needed to elucidate the transmission dynamics.

Red fox (Vulpes vulpes) as a potential reservoir host of cardiorespiratory parasites in Bosnia and Herzegovina

Red fox (Vulpes vulpes) is considered as reservoir of different cardiorespiratory parasites of veterinary and medical importance. Since data on cardiorespiratory parasites in foxes in Bosnia and Herzegovina are still lacking, the aims of the present study were to (i) investigate the prevalence and geographical distribution of these parasites, (ii) determine genetic diversity of detected parasite species, and (iii) to estimate the role of foxes in the transmission cycle to companion animals and humans. Four species, morphologically and molecularly identified as Eucoleus boehmi (64.6%; 51/79), Eucoleus aerophilus (69.7%; 154/221), Crenosoma vulpis (45.7%; 101/221) and Linguatula serrata (1.3%; 1/79) were retrieved from nasal cavity and lungs in 184 (83.3%) animals. The occurrence of heartworms, Angiostrongylus vasorum and Dirofilaria immitis was not detected by necropsy or PCR. Furthermore, three distinct haplotypes of E. aerophilus (I, III, XV) and two of C. vulpis (I, II) previously reported in pet animals and wild carnivores were confirmed in this study. A new haplotype of C. vulpis (designated as haplotype V) was also identified based on 12S rRNA gene for the first time. The present study indicates a high prevalence and wide distribution of nasal and lung nematodes in fox population in Bosnia and Herzegovina, and supports the existence of transmission patterns between wildlife and pet animals.