Feline pulmonary nematodes; new challenges for veterinary practitioners

Pulmonary parasitic diseases have become a frequent feline condition. Aelurostrongylus abstrusus, Troglostrongylus brevior and Capillaria aerophila appear to be the main pathogenic factors. Felines that are affected may display respiratory as well as non-specific symptoms. Diagnostic methods include copromicroscopic, serological and molecular detection, whereas the treatment should be both symptomatic and elective.

CPD article: Felid lungworms: from complete strangers to major parasites

The parasitic nematodes Aelurostrongylus abstrusus, Troglostrongylus brevior and Capillaria aerophila affect the respiratory system of cats and are a primary cause of respiratory disease in cats in many countries. While they have been underestimated for a long time, in recent years academics and veterinarians have become more aware of their importance, and now felid lungworms are recognised as primary agents of respiratory disease. Therefore, timely diagnosis and treatment, and efficacious prevention methods are a priority in feline clinical practice. Recent data have unveiled many features of diseases caused by these nematodes, and this article reviews and discusses practical and clinical knowledge, as well as recent updates on clinical management of aelurostrongylosis, troglostrongylosis and capillariosis in cats.

Endoparasites of European Wildcats (Felis silvestris) in Greece

The European wildcat (Felis silvestris) is the only wild felid living in Greece. Wildcat populations are declining due to anthropogenic and phenological unfavourable conditions, and parasites may have an additional negative impact. In the present study, the occurrence of endoparasites in wildcats in Greece and the potential threats posed to wildcats, domestic animals, and humans in the study areas has been investigated. In a six-year period, 23 road-killed wildcats and 62 wildcat faecal samples were collected from different areas of the country. Necropsy for the detection of endoparasites and standard parasitological examinations of faecal samples were performed. Parasites were morphologically identified and, in selected cases, molecularly analysed. All necropsied wildcats (100%) were infected by three to 10 different parasite taxa, with the most prevalent being Taenia taeniaeformis (73.9%), Toxocara cati (60.9%), Angiostrongylus chabaudi (56.5%), Ancylostoma tubaeforme (39.1%), Cylicospirura spp. (34.8%), Troglostrongylus brevior (34.8%), and Capillaria aerophila (33.8%). Of the 62 faecal samples examined, 53 (85.5%) were positive for one or more parasite elements (larvae, eggs, or oocysts). The most frequent were T. cati (45.2%), A. chabaudi (29%), C. aerophila (24.2%), and Ancylostomatidae (17.7%). This is the first survey on endoparasites affecting wildcats in Greece. Some of the parasites here found are frequent in domestic and wild felids, while others, i.e., Oslerus rostratus and Cylicospirura petrowi, were described for the first time in the European wildcat. Most of them have a significant pathogenic potential, causing severe to hazardous diseases to infected felids and some, under specific circumstances, can also threaten human health.

Cat Respiratory Nematodes: Current Knowledge, Novel Data and Warranted Studies on Clinical Features, Treatment and Control

The nematodes Aelurostrongylus abstrusus, Troglostrongylus brevior and Capillaria aerophila are the most important parasites inhabiting the airways of cats. They are receiving growing attention from academia, pharmaceutical companies and veterinarians, and are now considered a primary cause of respiratory diseases in feline clinical practice and parasitology. In the past few years, several studies have been conducted in both natural and experimental settings to increase knowledge, provide new insights and fill gaps on respiratory parasitoses of cats. Awareness and knowledge of clinical scenarios towards appropriate and timely diagnosis and prompt and efficacious treatment options have become a priority to investigate. At the same time, chemopreventative approaches have been evaluated to assess the geographical spreading of these parasites and the rise in the number of clinical cases in cat populations of different countries. Given the intense accumulation of novel data, this review presents and discusses the state of the art and the latest updates on the clinical features, treatment, and control of major respiratory parasitoses of cats. Moreover, food for thought is also provided with the aim of spurring on new studies in the near future.

The Prevalence of Endoparasites in Slovakian Household Dogs and Cats

Pets play a pivotal role as definitive or reservoir hosts for many zoonotic parasites. Dogs and cats without any clinical signs may be a carrier for the infection. In a one-year-study, collected fecal samples of 257 dogs and 50 cats were examined coproscopically for the endoparasite infections. Out of 307 investigated fecal samples 107 (34.9%) were positive for the presence of the propagative stages of endoparasites. In 257 of dogs fecal samples, 12 different species of endoparasites were detected: Giardia spp., Cystoisopsora spp., Sarcocystis spp., Hammondia/Neospora-like, Angiostrongylus vasorum, Capillaria aerophila, Crenosoma vulpis, Toxocara canis, Toxascaris leonina, Trichuris vulpis, Strongyloides stercoralis and eggs from the family Ancylostomatidae. Only 4 different parasitic species were found in 50 domestic cats’ fecal samples - Giardia spp., Cystoisopsora spp., T. cati and larvae of Aelurostrongylus abstrusus. It was confirmed that a significant differences were found in relation to age for Giardia spp., T. canis, S. stercoralis and family Ancylostomatidae. Close and frequent contact between younger pets and people increases the risks for the transmission of zoonotic diseases.

Efficacy of milbemycin oxime/afoxolaner chewable tablets (NEXGARD SPECTRA®) against Capillaria aerophila and Capillaria boehmi in naturally infected dogs

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 < 0.05 for both time points). Twelve of the 13 dogs in the NEXGARD SPECTRA® 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.

An Unusual Case of Mixed Respiratory Capillariosis in a Dog

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.

INFECÇÃO PARASITÁRIA PULMONAR EM Puma yagourandi: RELATO DE CASO (Pulmonary parasitic infection in Puma yagourandi: case report)

Aelurostrongylus abstrusus é um nematódeo pouco diagnosticado na rotina veterinária, onde os parasitas adultos têm como localização as vias aéreas de felinos e a postura de ovos pode acontecer no parênquima pulmonar ou em pequenos vasos alveolares, os quais eclodem as larvas de primeiro estágio (L1), que ao serem deglutidas são eliminadas com as fezes. No ambiente, as larvas encontram os hospedeiros intermediários, podendo ainda se disseminar por diversos hospedeiros paratênicos. Os felinos se infectam através da ingestão dos moluscos contendo as larvas infectantes (L3) ou ingerindo os hospedeiros paratênicos, e após a digestão, as larvas atingem os pulmões migrando pelo sistema circulatório e linfático, onde evoluem para adultos. A maioria das infecções são assintomáticas, entretanto, em casos mais graves os animais podem desenvolver complicações, como pneumonia, efusão pleural, piotórax, entre outras, podendo ser fatais. O presente trabalho teve por objetivo descrever as alterações de um caso de infecção natural por A. abstrusus em gato mourisco (Puma yagourandi), diagnosticado pelos Laboratórios de Doenças Parasitárias dos Animais (DOPA) e Patologia Veterinária (LPV) da Universidade Federal do Paraná (UFPR), Setor Palotina. O felino que havia sido vítima de atropelamento, chegou ao Hospital Veterinário da UFPR já morto sendo prontamente encaminhado a necropsia. Na análise macroscópica, o pulmão apresentava áreas multifocais a coalescentes moderadamente avermelhadas e hipocrepitantes, além de presença multifocal de estruturas parasitárias ao corte. Na análise histopatológica, foi observada uma pneumonia granulomatosa multifocal moderada, composta por linfócitos, macrófagos, plasmócitos e células gigantes do tipo Langerhans. No lúmen bronquial, no centro do infiltrado, notou-se a presença de um parasita de forma arredondada, de aproximadamente 350 µm de diâmetro, com cavidade celomática, trato digestório musculoso e aparelho reprodutivo bem evidente, com múltiplos ovos larvados em seu interior, camada muscular delgada e cordões laterais paralelos evidentes (compatíveis com A. abstrusus). No lúmen dos bronquíolos havia grande quantidade de ovos em diferentes estágios de desenvolvimento larval, medindo de 80 a 150 µm de diâmetro. O epitélio bronquial e a camada muscular das arteríolas estavam moderadamente espessados com aumento no número de camadas celulares (hiperplasia) e no lúmen dos alvéolos, havia moderada quantidade de macrófagos espumosos. Durante a necropsia, foram coletados espécimes de parasitas provenientes do pulmão, assim como, amostra de lavado traqueobronquioalveolar, ambas foram encaminhadas ao DOPA. As amostras foram analisadas através do método parasitológico direto, com auxílio do microscópio de luz, estereomicroscópico e chaves para a identificação de nematódeos (VICENTE et al, 1997). Na amostra de lavado traqueobronquioalveolar, foi possível visualizar ovos larvados e larvas que foram identificadas e classificadas como A. abstrusus, assim como os espécimes adultos. A aelurostrongilose felina é uma doença negligenciada, subdiagnosticada e, grande parte das infecções são assintomáticas e acabam sendo um achado anatomopatológico, como no presente estudo. Desta forma, torna-se importante realizar o acompanhamento coproparasitológico dos felinos para realização do diagnóstico precoce e diagnóstico diferencial para outras infecções respiratórias como Trogostrongylus brevior, Capillaria aerophila e Angyostrongylus vasorum (que apresenta potencial zoonótico).

Clinical-parasitological screening for respiratory capillariosis in cats in urban environments

SummaryRespiratory capillariosis is a widely distributed zoonotic parasitic disease caused by the nematode Capillaria 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.

Conquering Switzerland: the emergence of Angiostrongylus vasorum in foxes over three decades and its rapid regional increase in prevalence contrast with the stable occurrence of lungworms

Angiostrongylus vasorum, Crenosoma vulpis and Capillaria aerophila are the most common lungworms of domestic and wild canids. We investigated the short- and long-term lungworm prevalence changes in the Swiss fox population with a focus on A. vasorum. Between 2012 and 2017, lungs and hearts of 533 foxes from north-eastern Switzerland were necropsied and blood samples tested for circulating A. vasorum antigen. Angiostrongylus vasorum prevalence increased steadily from 21.5% in 2012 to 81.8% in 2017. In contrast, C. aerophila and C. vulpis prevalences fluctuated between 41.8 and 74.7%, and 3.6 and 14.9%, respectively. Based on 3955 blood samples collected between 1986 and 2017 from three geographic areas and during four time periods, antigen seropositivity increased from 2.4 to 62.0%. In north-eastern Switzerland, seropositivity was initially low (1.9 and 1.7% in the first two time periods) but increased in the following two decades to 22.2 and 62.0%, respectively. Our findings depict the spectacular expansion of A. vasorum in the past three decades. Regionally, the prevalence in foxes increased 4-fold within 6 years in some regions. This underpins the important role of foxes as reservoir hosts, likely explaining the increasing number of cases of canine angiostrongylosis in Switzerland. Our findings are representative of central Europe and may help anticipating future developments in areas where A. vasorum is present but (still) infrequent.