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Background Capillaria aerophila and Capillaria boehmi parasitize the respiratory system of wild and domestic carnivores. Capillaria aerophila inhabits the trachea and bronchi of dogs and cats, while C. boehmi affects the nasal cavities and sinuses of dogs. In dogs the infection may be subclinical or characterized by varying respiratory distress. Methods The present study evaluated the efficacy of an oral formulation containing milbemycin oxime and afoxolaner (NEXGARD SPECTRA®) in dogs naturally infected with C. aerophila and/or C. boehmi from three enzootic areas of Italy. Dogs were enrolled pending fecal examination and molecular confirmation of respiratory capillarioses. Dogs were allocated in two groups: Group 1 (G1, 25 dogs), treated with a negative control product with no anthelmintic activity (afoxolaner, NEXGARD®), and Group 2 (G2, 26 dogs), treated with NEXGARD SPECTRA®. At the day of treatment administration (Day 0), all dogs were clinically examined. Dogs were again subjected to clinical and fecal examinations at Days 28 (± 4) and 56 (± 2). The primary criterion for treatment efficacy was the reduction of fecal Capillaria egg counts in G2 compared with G1. The regression of/recovery from baseline clinical signs was considered as a further efficacy criterion. Results Percentage reduction of fecal Capillaria egg counts in the NEXGARD SPECTRA® group compared to the control group was > 97% on Day 28 and 100% on Day 56, respectively (p ® group with respiratory signs prior to treatment were free of clinical signs at the end of the study. Conversely, the six control group dogs with respiratory signs prior to treatment remained symptomatic. Conclusions Results of the present study showed that NEXGARD SPECTRA® was safe and highly efficacious in the reduction of C. aerophila and C. boehmi eggs after one treatment with a complete reduction of the egg output after the second administration associated with a recovery from respiratory signs. Graphical Abstract

Nematodes belonging to the genus Capillaria infect a range of domestic and wild animals. Capillaria aerophila and Capillaria boehmi cause respiratory parasitoses in dogs and wild carnivores, e.g., foxes and mustelids, although they are often overlooked in canine clinical practice. The present report describes an unusual case of a severe and mixed infection by C. aerophila and C. boehmi in a privately housed dog that showed acute and life-threatening respiratory and neurological signs. Clinic-pathologic and epizootiological implications are described and discussed.

Dogs can be infected by several nematodes of the Trichuridae family. Trichuridae eggs are all similar, barrel shaped with polar plugs, and misdiagnosis among different species can occur. The most common species is Trichuris vulpis, while the respiratory parasites Eucoleus boehmi (syn. Capillaria boehmi) and Eucoleus aerophilus (syn. Capillaria aerophila) are rarely observed in pets. E. boehmi is reported for the first time in this study in north-western Italy with other Trichuridae. Dog faecal samples (270) were examined by flotation. E. boehmi (2.2%), E. aerophilus (4.4%) and T. vulpis (12.2%) were found; identification was done with measurements and through observation of morphological characters already known. The specific identification of E. boehmi was confirmed using scanning electron microscopy: its egg shell shows a dense network with a fine mesh, surrounding small pits, on the contrary E. aerophilus eggs present a thick mesh with wide depressions, while T. vulpis eggs surface is smooth.

The efficacy and safety of a spot-on formulation containing 10% imidacloprid and 2.5% moxidectin (Advocate®, Bayer Animal Health GmbH, Leverkusen, Germany) were evaluated in a pilot trial for the treatment of canine nasal capillariosis caused by Capillaria boehmi (syn. Eucoleus boehmi). Sixteen dogs copromicroscopically positive for C. boehmi eggs were confirmed, either by rhinoscopy or species-specific PCR-coupled sequencing assays, as being affected by nasal capillariosis. The animals were randomly allocated to two different study groups, i.e. one (Group T) treated with Advocate® and one (Group C) left untreated, in a ratio of 1:1. The animals underwent clinical examination and quantitative copromicroscopy for C. boehmi eggs on Days -6 and -2 (baseline) and Day 28 ± 2 (post-baseline). Animals in Group T received Advocate® on Day 0. On Day 28 ± 2 the efficacy of the treatment (Group T) or the persistence of the infection (Group C) was confirmed by rhinoscopy or, alternatively, by molecular procedures. Seven of the eight dogs in Group T were negative on Day 28 ± 2 (reduction of baseline faecal egg counts by 99.14%), while for one dog a second treatment on Day 28 ± 2 was necessary to clear the infection, as demonstrated on Day 56 ± 2 (reduction of baseline faecal egg counts by 100% in Group T). Seven animals in Group C received a rescue dose of Advocate® on Day 28 ± 2 and scored microscopically and molecularly negative for the parasite on Day 56 ± 2, thus increasing the reduction of post-baseline egg counts to 99.57% after a single administration. These promising results show that Advocate® spot-on is an effective formulation for the treatment of canine nasal capillariosis under field conditions.

A 4-year-old, spayed-female great Dane was referred for surgical treatment of a suspected meningioma, diagnosed on magnetic resonance imaging 10 days prior to presentation. The suspected meningioma was removed via image-guided stereotactic craniotomy. Histopathological diagnosis was severe, locally extensive, chronic meningoencephalitis with an intralesional nematode egg. The egg was morphologically consistent with Eucoleus boehmi, and aberrant migration into the cranial cavity was the presumed cause of this lesion. Three faecal samples were collected and revealed 4+ E. boehmi eggs. Treatment involved 110 mg/kg fenbendazole (Panacur, Intervet) orally twice daily for 14 days. Nematodes including E. boehmi are a previously un-recognised source of intracranial disease in dogs, and should be considered as a differential for mass-like lesions visualised by magnetic resonance imaging.

Background Capillaria aerophila, Capillaria boehmi and Trichuris vulpis are trichuroid nematodes affecting wild and companion animals all over the World. The canine intestinal whipworm, T. vulpis, is the most common and well- known in veterinary practice, whereas the respiratory C. aerophila and C. boehmi have been rarely reported in pets as a likely consequence of overlapping morphometric and morphological features of the eggs, which impair a correct etiological diagnosis. Findings In December 2011, a mixed infestation by T. vulpis, C. aerophila and C. boehmi was diagnosed in an asymptomatic dog living in central Italy. Morphometric and morphological findings and pictures of the eggs found at the copromicroscopic analysis are herein reported. Conclusions The present work demonstrates that when trichuroid eggs are found in a faecal sample from a dog, a careful morphological and morphometric analysis of individual parasite elements is mandatory. Key diagnostic features (i.e., size, wall surface pattern and aspects of plugs) should be carefully examined when eggs with overlapping shape and appearance are detected. In conclusion, given the importance in clinical practice of canine trichuroids and the zoonotic potential of C. aerophila, these nematodes should be included into the differential diagnosis of intestinal and respiratory parasitoses of dogs by a thorough microscopic analysis of all trichuroid ova present in microscopic fields.