Gross and histopathological changes associated with Aelurostrongylus abstrusus and Troglostrongylus brevior in a kitten

Clinical efficacy of a parasiticide formulation containing eprinomectin, esafoxolaner and praziquantel (NexGard® Combo) in the treatment of natural feline aelurostrongylosis and troglostrongylosis

The metastrongyloids Aelurostrongylus abstrusus and Troglostrongylus brevior are primary causes of feline clinical respiratory disease. The present field trial evaluated the clinical efficacy of a spot-on formulation containing eprinomectin, esafoxolaner and praziquantel (NexGard® Combo) administered per label recommendations to cats affected with aelurostrongylosis and/or troglostrongylosis. Overall, 36 naturally infected cats were randomly assigned to Group 1 (G1) or Group 2 (G2) of 18 cats each. The two groups included 6 cats with A. abstrusus, T. brevior and mixed infection, each. All cats completed the study. Cats in G1 were treated on study Days (SDs) 0 and 28±2. Cats in G2 served as negative control until SD 56±2 and were then treated on SD 56±2 and 84±2. On SD 0/-7, 28±2 and SD 56±2 all cats were subjected to parasitological (quali-quantitative Baermann) and clinical examinations (physical exams and thoracic X-rays). Hematology and biochemistry analyses were performed on SD 0/-7 and SD 56±2. On SD 84±2 quali-quantitative Baermann, clinical examination and thorax radiography were performed on all G2 cats and on two G1 cats that still had radiographic alterations on SD 56±2. On SD 112±2 all G2 cats were subjected to parasitological and clinical evaluations and one cat from G1 that still had radiographic signs at SD 84±2 was clinically and radiographically evaluated. Efficacy criteria were the reduction of larval shedding in faeces and the clinical response in terms of pathological and radiographic scores after treatment compared to the baseline. An efficacy of 100 % based on LPG reduction was recorded after one (20/24 cats) or two (all 24 cats) treatments in cats with single infection by A. abstrusus or T. brevior. For cats with mixed infections, larval shedding was stopped after one (11/12 cats) or two (all 12 cats) treatments. Statistically significant clinical and radiographic improvement was evident in all study cats after 2 treatments. The present data show that two monthly treatments with NexGard® Combo stopped larval shedding and led to a significant clinical recovery and a complete resolution of radiographic abnormalities in cats infected with A. abstrusus and/or T. brevior.

Comparative analysis of diagnostic methods and risk factors for Aelurostrongylus abstrusus infection in brazilian cats

This study aimed to prospectively evaluate the risk factors of infection by Aelurostrongylus abstrusus in Brazilian cats with cough and/or radiographic changes, using as diagnostic tools the Baermann method (BM), polymerase chain reaction (PCR) of feces, bronchoalveolar lavage fluid (BALF), and cytology. Forty-three cats that were presented with cough or lung radiographic abnormalities compatible with bronchoalveolar disease were included in the study. After clinical evaluation, feces samples were collected to investigate lungworm parasitism through BM and PCR. BALF was performed to provide samples for cytology, bacteriology, and fungal culture. Stool PCR was considered the gold standard for diagnosis tests, and the other methods were evaluated by their agreement. PCR presented 74% (32/43) of positivity for A. abstrusus, while in the BM, 41% (18/43) were positive. BM showed sensitivity of 56.25% and specificity of 100% when compared with PCR. No larva was found in the cytological evaluation of 21 BALF samples. Lungworm is an important cause of bronchopulmonary disease in domestic cats in Brazil and should be included as a differential diagnosis when a cat is presented with cough or radiographic abnormalities. BM is a sensitive, non-invasive, and cheap technique to diagnose the disease, but it is not as sensitive as PCR.

Metastrongyloid Infection with Aelurostrongylus abstrusus, Troglostrongylus brevior, Oslerus rostratus and Angiostrongylus chabaudi in Feral Cats from the Canary Islands (Spain)

Lungworms are a major cause of feline respiratory disease, frequently underdiagnosed due to its presentation of symptoms being similar to that of other feline respiratory pathologies. Epidemiological data about these nematodes are scarce in the Canary Islands (Spain). Given the veterinary importance of these parasites, the aim of the present study was to improve the current epidemiological knowledge of the lungworm species that could be affecting feral cats in this archipelago. A total of 29 feral cats from La Gomera were analyzed. The respiratory tract of each animal was inspected and the nematodes obtained were identified by morphological keys and molecular techniques. Metastrongylids were detected to be widely distributed throughout the island with a prevalence of 55.2% (16/29). The species Aelurostrongylus abstrusus, Troglostrongylus brevior, Oslerus rostratus and Angiostrongylus chabaudi were identified. Also, coinfections with A. chabaudi and O. rostratus were detected in two animals. The present study shows a high diversity of lungworms in feral cats in La Gomera, with the first report of A. chabaudi and T. brevior for the Canary Archipelago and the first citation of A. chabaudi in cats for Spain. The wide distribution and high prevalence found in this study indicate a high risk of exposure to pulmonary infections in cats.

The giant African snail Achatina (Lissachatina) fulica Bowdich, 1822 as an intermediate host of Aelurostrongylus abstrusus (Railliet, 1898) in the Rio de Janeiro state, Brazil

Aelurostrongylus abstrusus is a metastrongilid nematode that causes feline aelurostrongylosis. The adult life stage parasitizes the lungs of wild and domestic felids. Terrestrial mollusks act as its intermediate host, and birds, amphibians, and small mammals act as paratenic hosts. Aelurostrongylus abstrusus presents a worldwide distribution, and in Brazil it has been recorded in most states. The present study investigates the occurrence of Aelurostrongylus abstrusus in terrestrial mollusks from urban areas of two out of the six Mesoregions of Rio de Janeiro state: Metropolitana and Centro Fluminense (46 municipalities). Larvae were recovered from the tissue of the mollusks collected during the surveys and identified based on morphology and sequences of the Internal Transcribed Spacer 2 (ITS2). In all, 2791 mollusks, belonging to 14 different species, were collected. Larvae of A. abstrusus were recovered from two species: Achatina fulica in 22 out of 46 municipalities, and from the slug Latipes erinaceus in 1 out of 46 municipalities. Aelurostrongylus abstrusus was recorded in half (50%) of the municipalities of the Metropolitana Mesoregion and in 44% of those of the Centro Fluminense Mesoregion. Results indicate a strong association between A. abstrusus and A. fulica, since 99% of the mollusks infected with A. abstrusus were A. fulica. This study recorded A. abstrusus in the Centro Fluminense Mesoregion and naturally parasitizing L. erinaceus for the first time. Despite the high number of mollusks infected with A. abstrusus and their wide distribution in Rio de Janeiro State, there are still few reports of infection in Brazilian felids, probably given that this is an under-diagnosed parasitosis in this country. Further studies in other regions of the Rio de Janeiro State, and other Brazilian States, focusing on intermediate and definitive hosts, particularly in the urban environments where they coexist, are needed. These studies will enable further understanding of the epidemiology and prevention of aelurostrongylosis.

Gastrointestinal parasites in dogs and cats in line with the One Health' approach

ABSTRACT Dogs and cats are frequently affected by gastrointestinal parasites of medical and veterinary concern. The correct diagnosis is pivotal to the treatment outcome, reducing the risk of environmental contamination and spreading of these pathogens. The aim of this study was to determine the prevalence of gastrointestinal parasites of domiciled dogs and cats in an urban area of Northeastern Brazil, as well as to discuss the findings from a “One Health” perspective. Fecal samples (n = 231) of dogs (n = 126) and cats (n = 105) were obtained directly from the environment after spontaneous defecation, and subsequently analyzed through the Mini-FLOTAC and Baermann techniques. Of all samples, 28.14% (65/231) presented immature forms of gastrointestinal parasites, with 31.75% (40/126) and 23.81% (25/105) of dogs and cats positive, respectively (x 2 = 1.413; p = 0.2345). Two genera of helminths (Ancylostoma and Toxocara) and two genera of protozoa (Cystoisospora and Entamoeba) were identified. Additionally, co-infections were observed in 15% (6/40) of positive dogs and 28% (7/25) of positive cats (p = 0.2207). None metastrongyloid larvae were detected. In conclusion, animals herein assessed presented a high prevalence of zoonotic gastrointestinal nematodes. Therefore, preventive measures against these neglected parasites should be stimulated.

Canine and Feline Parasitology: Analogies, Differences, and Relevance for Human Health

Cats and dogs are treated as family members by most pet owners. Therefore, a high quality of veterinary care and preventive medicine is imperative for animal health and welfare and for the protection of humans from zoonotic pathogens. There is a general perception of cats being treated as "small dogs," especially in the field of clinical parasitology. As a result, several important differences between the two animal species are not taken into proper consideration and are often overlooked. Dogs and cats are profoundly different under evolutionary, biological, ethological, behavioral, and immunological standpoints. These differences impact clinical features, diagnosis, and control of canine and feline parasites and transmission risk for humans. This review outlines the most common parasitoses and vector-borne diseases of dogs and cats, with a focus on major convergences and divergences, and discusses parasites that have (i) evolved based on different preys for dogs and cats, (ii) adapted due to different immunological or behavioral animal profiles, and (iii) developed more similarities than differences in canine and feline infections and associated diseases. Differences, similarities, and peculiarities of canine and feline parasitology are herein reviewed in three macrosections: (i) carnivorism, vegetarianism, anatomy, genetics, and parasites, (ii) evolutionary adaptation of nematodes, including veterinary reconsideration and zoonotic importance, and (iii) behavior and immune system driving ectoparasites and transmitted diseases. Emphasis is given to provide further steps toward a more accurate evaluation of canine and feline parasitology in a changing world in terms of public health relevance and One Health approach.

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.

Efficacy of a topical combination of eprinomectin, praziquantel, fipronil and (S)-methoprene against developing and adult Troglostrongylus brevior lungworms (Nematoda, Crenosomatidae) in cats

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Broadline® is 100 % effective against Troglostrongylus brevior in cats.

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A treatment has beneficial effects on pathology and health status of the cats.

The efficacy of the eprinomectin, praziquantel, fipronil and (S)-methoprene combination parasiticide Broadline® (Boehringer Ingelheim Animal Health) was evaluated against developing larval and adult stages of Troglostrongylus brevior, a metastrongyloid pulmonary nematode which is reported to parasitize domestic cats in southern Europe with increasing frequency.

Twenty four purpose-bred cats were experimentally infected with 100 third-stage T. brevior larvae each and randomly allocated to either remain untreated (control) or to be treated with the combination product when T. brevior were developing larval (6 days post inoculation, dpi) or adult nematodes (28 dpi) (eight cats per group). Treatments were administered topically at the minimum label dose of 0.12 mL/kg. Fecal samples of the cats were examined to confirm the presence of patent (adult) nematode infections prior to treatment at 28 dpi and to monitor the larval excretion. At necropsy (49 dpi), the weight of the pulmonary lymph nodes and lungs were determined, and T. brevior lungworms were recovered and counted.

All control animals and cats to be treated at 28 dpi excreted T. brevior larvae 24 dpi and 26 dpi while no larvae were excreted by the cats treated at 6 dpi. Following treatment at 28 dpi, T. brevior larval excretion decreased immediatetly and ceased prior to necropsy. Nematode counts demonstrated that treatment with the combination product was 100 % efficacious against both developing larval and adult T. brevior: no lungworms were recovered from any treated cat while all control animals harbored T. brevior (range, 6–52) (p < 0.001).

No treatment-related health problems or any other clinical signs were observed in the cats. However, significantly higher absolute and relative (organ weight to body weight ratio) pulmonary lymph node weights of the control animals compared with the treated cats at 6 dpi (p < 0.001 and p < 0.001, respectively) and at 28 dpi (p = 0.003 and p = 0.019, respectively) indicated the pathology of the T. brevior infection.

In conclusion, the combination product was demonstrated to be 100 % efficacious against developing larval and adult T. brevior. Furthermore, it was demonstrated that indicators of impaired respiratory and immune systems resultant from T. brevior infection can be prevented with an efficacious treatment when administered during the pre-patent period of infection or are improving substantially within three weeks of treatment of cats harboring adult lungworms.

First case report of nematode parasitic myelopathy in a wild feline in Brazil

Parasitic myelopathy caused by Gurltia paralysans in domestic cats is a disease commonly reported in several South American countries. The adult parasite is lodged in the meningeal veins and spinal cord, often causing clinical manifestations of vascular proliferation, thrombophlebitis, and medullary compression. Wild felines are believed to be the definitive hosts of this parasite. The infection occurs through the ingestion of paratenic hosts, but the life cycle of G. paralysans is not yet clearly understood. In this paper, we discuss a case of parasitic myelopathy in a margay (Leopardus wiedii) that died during post-surgical care. Necropsy revealed focal hemorrhages in the thoracolumbar spinal cord. A microscopic examination revealed adult nematodes and eggs inside the veins of subarachnoid space in spinal cord, suggesting G. paralysans infection. This is first description of parasitic myelopathy in a margay in Brazil.

Molecular Survey of Metastrongyloid Lungworms in Domestic Cats (Felis silvestris catus) from Romania: A Retrospective Study (2008-2011)

Background: Lungworms are recognized as important agents in the pathology of the respiratory system in domestic cats. While Aelurostrongylus abstrusus is worldwide known and studied, Troglostrongylus brevior has gained the attention of the scientific community only in the last decade. The pathogenicity of this species seems to be higher than A. abstrusus, causing more severe clinical presentations and being potentially fatal, especially in young animals. Methods: In this study, 371 DNA isolates of faecal samples were tested by multiplex polymerase chain reaction for the presence of A. abstrusus, T. brevior, and Angiostrongylus chabaudi. Results: The results showed that 30.2% and 6.7% of the investigated domestic cats were positive for A. abstrusus and T. brevior respectively, stressing out the importance of these parasites as agents of respiratory conditions in domestic cats from Romania. None of the samples were positive for A. chabaudi. The age, the outdoor access, and the lack of deworming were identified as significant risk factors for infection with A. abstrusus. Conclusions: This paper represents the first report of T. brevior in domestic cats from Romania. Moreover, it presents the most northern localization in Europe of T. brevior.

First report of Aelurostrongylus abstrusus in St. Kitts

A 4-month-old intact male domestic shorthair kitten living in St Kitts, West Indies presented with respiratory distress, cachexia, and mucopurulent nasal discharge. Thoracic radiographs revealed a diaphragmatic hernia. The diaphragmatic hernia as well as subpleural pulmonary nodules suspicious for verminous pneumonia were identified during a postmortem examination. Histology showed multifocal to coalescing pyogranulomatous and eosinophilic pneumonia centered on larvae and morulated eggs. The lesion and nematode morphology were consistent with Aelurostrongylus abstrusus. Although Aelurostrongylus abstrusus has been reported worldwide, this is the first report of a metastrongyloid lungworm in cats in St. Kitts and for the West Indies. This case report should increase the awareness of A. abstrusus pneumonia in cats from St. Kitts and other locations in the eastern Caribbean.

Survey of lungworm infection of domestic cats in Hungary

From 61 settlements of 12 Hungarian counties, 303 domestic cats were included in this survey. Between autumn 2016 and spring 2018, fresh faecal samples were randomly collected and examined by flotation and by the Baermann-Wetzel method for the presence of lungworm infection. No eggs of Eucoleus aerophilus were detected. Morphological identification of first instar larvae (L1) was also carried out. In the faeces of 60 cats (19.8%) from 17 settlements and Budapest, L1 of Aelurostrongylus abstrusus were found. More than half of the cats were from the western part of the country. The average number of larvae per gram of faeces was 190.2 ± 304.88. These results are in line with the former findings on the prevalence of aelurostrongylosis of domestic cats in Hungary. In addition, Oslerus rostratus was also found for the first time in the faecal samples of three cats from the eastern part of the country, infected also with Ae. abstrusus. The average age (2.51 ± 1.26 years) of infected cats indicates that lungworm infection is more common among younger cats. No relationship was found between the lung-worm infection and the sex of cats. Non-neutered cats had a significantly higher proportion of lungworm infections. Two-thirds of the infected cats were apparently healthy, and only 19 individuals showed clinical signs of respiratory disorders.

Occurrence of canine and feline extra-intestinal nematodes in key endemic regions of Italy

Extra-intestinal nematodes of companion animals are of growing concern in veterinary medicine for their pathogenic potential and the current expansion throughout Europe. The present study has evaluated the occurrence of major canine and feline extra-intestinal nematodes in regions of Italy having epidemiological relevance. Associations of various recorded parameters related to the examined animals have been statistically evaluated, along with a comparative analysis with the most recent epidemiological data. Overall, 1055 dogs and 1000 cats were tested. Among extra-intestinal nematodes Angiostrongylus vasorum was the most common in dogs followed by Capillaria aerophila and Dirofilaria spp.; Aelurostrongylus abstrusus was the most recorded parasite in cats, followed by C. aerophila and Troglostrongylus brevior. The statistical analysis revealed that outdoor access is associated with A. vasorum, A. abstrusus and T. brevior infections, that were also more prevalent in animals with cardio-respiratory signs. Moreover, cats aged less than 12 months had more chances to be infected by lungworms. The data herein presented confirm the occurrence and the possible risk of expansion of different extra-intestinal parasitoses of dogs and cats in Italy, underlining the importance of a constant epidemiologic vigilance and of appropriate control methods.

Feline Troglostrongylosis: Current Epizootiology, Clinical Features, and Therapeutic Options

Parasitic bronchopneumonia plays an important role in feline respiratory medicine, thus it is receiving growing attention by researchers and practitioners. In recent years, Troglostrongylus brevior, a lungworm usually infecting wild felids, has been recognized as an agent of the lower respiratory tract in domestic cats. In particular, as a likely consequence of a spill-over from wild reservoirs (e.g., the European wildcat), T. brevior infection is increasingly reported in cats from Mediterranean and Balkan countries. This parasitic nematode has an indirect life cycle, and its biology overlaps that of the better known "cat lungworm" Aelurostrongylus abstrusus. In fact, cases of co-infections caused by both lungworms are not infrequent in domestic cats. Knowledge on clinical features of troglostrongylosis is still incomplete. Available data indicates that clinical signs and radiographic evidence are severe especially in kittens and young cats, are non-specific and often overlap with those of other feline respiratory diseases, such as feline bronchial disease/asthma, or infectious pneumonia. These characteristics make a definitive diagnosis of troglostrongylosis challenging, this disease requires a timely ancillary therapy and an appropriate anthelminthic treatment. As feline troglostrongylosis is an emerging parasitic disease of domestic cats, it should be included in differential diagnosis for lower respiratory tract disease in cats from regions where this parasite is present but also where it is unexpected. This article reviews current knowledge on the pathogenic role of T. brevior in domestic cats and resulting respiratory illness, with a special focus on clinical aspects, diagnosis, and management of the disease.

Novel approach to study gastropod-mediated innate immune reactions against metastrongyloid parasites

The anthropozoonotic metastrongyloid nematodes Angiostrongylus cantonensis and Angiostrongylus costaricensis, as well as Angiostrongylus vasorum, Crenosoma vulpis, Aelurostrongylus abstrusus and Troglostrongylus brevior are currently considered as emerging gastropod-borne parasites and have gained growing scientific attention in the last years. However, the knowledge on invertebrate immune responses and on how metastrongyloid larvae are attacked by gastropod immune cells is still limited. This work aims to describe an in vitro system to investigate haemocyte-derived innate immune responses of terrestrial gastropods induced by vital axenic metastrongyloid larvae. We also provide protocols on slug/snail management and breeding under standardized climate conditions (circadian cycle, temperature and humidity) for the generation of parasite-free F0 stages which are essential for immune-related investigations. Adult slug species (Arion lusitanicus, Limax maximus) and giant snails (Achatina fulica) were maintained in fully automated climate chambers until mating and production of fertilized eggs. Newly hatched F0 juvenile specimens were kept under parasite-free conditions before experimental use. An improved protocol for gastropod haemolymph collection and haemocyte isolation was established. Giemsa-stained haemolymph preparations showed adequate haemocyte isolation in all three gastropod species. Additionally, a protocol for the production of axenic first and third stage larvae (L1, L3) was established. Haemocyte functionality was tested in haemocyte-nematode-co-cultures. Scanning electron microscopy (SEM) and light microscopy analyses revealed that gastropod-derived haemocytes formed clusters as well as DNA-rich extracellular aggregates catching larvae and decreasing their motility. These data confirm the usefulness of the presented methods to study haemocyte-mediated gastropod immune responses to better understand the complex biology of gastropod-borne diseases.

Troglostrongylus brevior: a new parasite for Romania

Background

The genus Troglostrongylus includes nematodes infecting domestic and wild felids. Troglostrongylus brevior was described six decades ago in Palestine and subsequently reported in some European countries (Italy, Spain, Greece, Bulgaria, and Bosnia and Herzegovina). As the diagnosis by the first-stage larvae (L1) may be challenging, there is a possibility of confusion with Aelurostrongylus abstrusus. Hence, the knowledge on the distribution of this neglected feline parasite is still scarce. The present paper reports the first case of T. brevior infection in Romania. In July 2017, a road-killed juvenile male Felis silvestris, was found in in Covasna County, Romania. A full necropsy was performed and the nematodes were collected from the trachea and bronchioles. Parasites were sexed and identified to species level, based on morphometrical features. A classical Baermann method was performed on the lungs and the faeces to collect the metastrongyloid larvae. Genomic DNA was extracted from an adult female nematode. Molecular identification was accomplished with a PCR assay targeting the ITS2 of the rRNA gene.

Results

Two males and one female nematodes were found in the trachea and bronchioles. They were morphologically and molecularly identified as T. brevior. The first-stage larvae (L1) recovered from the lung tissue and faeces were morphologically consistent with those of T. brevior. No other pulmonary nematodes were identified and no gross pulmonary lesions were observed.

Conclusions

This paper represents the first report of Troglostrongylus brevior infection in Romania, so far representing the second northernmost location for this genus in Europe. The diversity of species infecting wild and domestic felids and the differences regarding the clinical significance of these nematodes highlight the need for a more intense surveillance and proper diagnosis of feline lungworm infections, especially in countries where more species were demonstrated to be present. Furthermore, an increased awareness between clinicians is needed for a correct diagnostic approach to feline lungworm diagnosis.

Single and mixed feline lungworm infections: clinical, radiographic and therapeutic features of 26 cases (2013-2015)

Objectives The aim of this study was to retrospectively describe clinical, radiographic and therapeutic features of feline lungworm infection. Methods Medical records of cats with lungworm diagnosis, thoracic radiography and without concurrent diseases between 2013 and 2015 were reviewed. Collection of data included physical examination, haematology, serum biochemistry, therapy with a variety of anthelmintics and outcomes. Results Thirty-seven records were recovered and 26 were included in the study. Single infections by Aelurostrongylus abstrusus (n = 15), Troglostrongylus brevior (n = 3) and Capillaria aerophila (n = 1) and coinfections by T brevior/ A abstrusus (n = 6) and T brevior/ C aerophila (n = 1) were diagnosed. The most common respiratory signs were coughing (n = 12), increased vesicular sounds (n = 10), dyspnoea (n = 9), such as laboured breathing, orthopnoea or open-mouth breathing, and tachypnoea (n = 6). Two cats were subclinically infected. The most common laboratory abnormality was anaemia (n = 7). Radiographic patterns recorded were interstitial (n = 24), bronchial (n = 21), alveolar (n = 10) and vascular (n = 2). Twenty-five cats had a complete recovery within 2-6 weeks of therapy. One kitten died 7 days after the diagnosis. Conclusions and relevance Lungworms should always be included in the differential diagnosis in cats living in endemic areas and presenting with respiratory signs and radiographic abnormalities. A copromicroscopic examination should be considered as the first diagnostic step for all cats at risk of lungworm infections. In most cases, timely therapy with a variety of anthelmintics guarantees recovery.

Mitochondrial haplotypes of Aelurostrongylus abstrusus and Troglostrongylus brevior (Nematoda, Metastrongyloidea) from domestic and wild felids

The lungworm Aelurostrongylus abstrusus is the most important respiratory parasite of domestic cats. Pulmonary aelurostrongylosis has been reported in wild felids, though unequivocally evidence of wildlife infection by A. abstrusus is scant. Recently, Troglostrongylus brevior, a lungworm usually infecting wild felids, has been described in domestic cats from Mediterranean areas. The present work evaluates the sequence variation of an informative region within the gene encoding the mitochondrial cytochrome c oxidase subunit 1 of A. abstrusus and T. brevior, in order to provide novel information on the genetic make-up of these lungworms. Parasitic stages of A. abstrusus and T. brevior were collected from domestic and wild hosts (i.e., domestic cat, European wildcat, caracal, serval, and lion) from Italy, Greece, and South Africa. Five (HI-HV) and four (HI-HIV) haplotypes were recorded for A. abstrusus and T. brevior, respectively, mostly shared between domestic and wild felids in different geographical areas. The phylogenetic analysis showed that all haplotypes of A. abstrusus and T. brevior clustered as monophyletic groups with a strong nodal support, indicating that all haplotypes identified were distinct from each other. All sequence types represent two distinct species, A. abstrusus and T. brevior, and these genetic convergences are also detected within and among populations of these nematodes, irrespective of their hosts and geographical origin. The occurrence of A. abstrusus and T. brevior haplotypes in different hosts from the same regions and between different countries indicates that the same lungworm populations circulate in domestic and wild hosts under the same routes of transmission.

OCCURRENCE OF LUNGWORMS IN EUROPEAN WILDCATS (FELIS SILVESTRIS SILVESTRIS) OF CENTRAL ITALY

The increasing focus on infections in domestic cats ( Felis catus ) has raised questions about lungworm distribution in wild hosts. To enhance knowledge of the occurrence of lungworms in enzootic regions of central Italy, we examined the carcasses of 16 European wildcats ( Felis silvestris silvestris). Adult nematodes, feces, respiratory flushings, and pulmonary tissues were collected at necropsy and then microscopically and genetically analyzed. Fourteen wildcats had single or mixed lungworm species. Aelurostrongylus abstrusus was the most common parasite retrieved, followed by Troglostrongylus brevior. In addition, three specimens of Angiostrongylus chabaudi were found in the pulmonary arteries of one wildcat. Histologically, the most common lesions were a mild-to-severe chronic catarrhal bronchitis and a chronic interstitial pneumonia with smooth muscle hypertrophy, associated with T. brevior and A. abstrusus , respectively. These results demonstrate that the European wildcats may harbor several species of lungworms that may impair their health and welfare. Also, F. s. silvestris is a potential reservoir for respiratory nematodes in domestic cats.

Diagnosis and management of lungworm infections in cats: Cornerstones, dilemmas and new avenues

PRACTICAL RELEVANCE

Respiratory parasites infecting domestic cats are attracting increased attention in feline clinical practice. In addition to the most commonly recognised 'cat lungworm' Aelurostrongylus abstrusus, Troglostrongylus brevior and Capillaria aerophila are now considered important pathogens of the respiratory tract of cats.

GLOBAL IMPORTANCE

These parasites are being increasingly diagnosed in several regions of the world and a continuous update on epidemiological changes and advances in diagnosis and control is of practical importance.

AIMS

This article reviews current knowledge of lungworms affecting cats, with a special focus on recent insights into diagnosis and management of the diseases they cause. The article also explores some potential new avenues for control of feline parasitic respiratory diseases, and highlights some key areas requiring further research.

Troglostrongylus brevior in an Eurasian lynx (Lynx lynx) from Bosnia and Herzegovina

Background

In the past few years the interest of the scientific community on lungworms of the genus Troglostrongylus has grown due to the increased number of unexpected cases of infections with Troglostrongylus brevior in domestic cats from Mediterranean Europe, likely due to a spill-over from wild reservoirs. Thus, there is a merit to increase our knowledge on the occurrence of this parasite in felids from European regions. The present paper describes lung lesions associated with T. brevior infection in the endangered Eurasian lynx (Lynx lynx) from Bosnia and Herzegovina.

Findings

The carcass of an illegally killed 3-year-old male Eurasian lynx was presented for necropsy at the Faculty of Veterinary Medicine of Sarajevo (Bosnia and Herzegovina). Grossly, multiple, multinodular, consolidated and firm, tan to grey areas, occupying the caudal third of caudal lung lobes, were observed. At cut section, the catarrhal fluid was draining from the airways. Larvae of T. brevior were found in tracheal scraping. The histopathological examination revealed multifocal to coalescing areas, centered on bronchi and bronchioles, and expanded alveoli filled with necrotic debris, degenerated inflammatory cells, mostly neutrophils and macrophages, and multiple cross sections of parasite larvae and thin-walled morulated eggs of lungworms. The paraffin-embedded lung samples were molecularly positive for T. brevior.

Conclusion

This paper describes the first record of T. brevior in the Eurasian lynx and the associated host lung pathology. Given its pathogenic potential and the lack of data on troglostrongylosis in lynx populations, the occurrence and impact of Troglostrongylus spp. on wildlife health as well as the role of L. lynx as reservoir of infection for other felids, should be further investigated.

Occurrence of Aelurostrongylus abstrusus and Troglostrongylus brevior in domestic cats in Greece

Background

Despite the evidence that Mediterranean Europe offers suitable conditions for the biology of felid respiratory metastrongyloids, no updated data on the presence of felid lungworms are available for Greece. Although the cat lungworm Aelurostrongylus abstrusus is considered as enzootic in domestic cats (Felis silvestris catus) living in some areas of continental Greece, conversely, Troglostrongylus brevior, has only been reported in the island of Crete. The present study aimed to evaluate the occurrence of Aelurostrongylus abstrusus and Troglostrongylus brevior in domestic cats from four different Greek locations including islands where European wildcats (Felis silvestris silvestris), believed to be the natural reservoir of T. brevior, are considered absent.

Methods

Faeces were collected from 125 stray cats in the city of Athens, and in Crete, Mykonos and Skopelos Islands, and examined by copromicroscopic techniques for the presence of lungworm larvae. When present, larvae were morphologically and molecularly identified.

Results

The occurrence of A. abstrusus and T. brevior was confirmed in 10 (8 %) and 7 (5.6 %) of the samples, respectively. In particular, T. brevior was detected in domestic cats in the city of Athens, and in Mykonos and Skopelos Islands, where wildcats are not present.

Conclusions

This information illustrates that T. brevior may infect domestic cats regardless of the presence of the natural host. Considering the relevant clinical impact of this nematode especially in young animals, it is advisable to include troglostrongylosis in the differential diagnosis of cat respiratory diseases also where this parasite is unexpected.

Felid Lungworms and Heartworms in Italy: More Questions than Answers?

Nematodes infecting the cardiorespiratory system of cats have recently stimulated high scientific interest. Over the past few years, different aspects of these parasites have been clarified and various issues elucidated. This increased knowledge has improved awareness on this topic but, at the same time, some dilemmas have not been solved and new questions have been raised. In this review, we underline and discuss current knowledge of, and new doubts relating to, feline lungworms and heartworms, with the aim of stimulating new studies to fill gaps of basic (i.e., epidemiology and biology) and applied (i.e., clinical aspects) knowledge of the old and new parasites affecting the cardiorespiratory system of cats.

Irreversible pulmonary hypertension associated with Troglostrongylus brevior infection in a kitten

A four month-old kitten was referred at the Veterinary Teaching Hospital of Teramo, Italy. Physical examination, echocardiography, thoracic radiography, copromicroscopy and biomolecular assays led to a diagnosis of severe parasitic bronchopneumonia by Troglostrongylus brevior complicated by pulmonary hypertension. A single administration of a spot on solution containing imidacloprid 10%/moxidectin 1% was effective in stopping larval shedding but clinical, radiographic and echocardiographic signs of bronchopneumonia and pulmonary hypertension still persisted after further follow-ups.While cases of pulmonary hypertension are known in infections by Aelurostrongylus abstrusus, this is the first report of irreversible pulmonary hypertension in a kitten with troglostrongylosis.

Respiratory nematodes in cat populations of Italy

The occurrence of common respiratory parasites of domestic cats (the metastrongyloid "cat lungworm" Aelurostrongylus abstrusus and the trichuroid Capillaria aerophila) and of neglected respiratory nematodes of felids (Troglostrongylus brevior, Angiostrongylus chabaudi and Oslerus rostratus) was here evaluated in two and three geographical sites of Northern and Central Italy, respectively. In 2014-2015, individual fecal samples of 868 domestic cats were examined microscopically and genetically, and epidemiological data related to parasitic infections were evaluated as possible risk factors by binary logistic regression models. The most common parasite was A. abstrusus in both mono- and poli-specific infections, followed by T. brevior and C. aerophila, while cats scored negative for other parasites. Cats positive for A. abstrusus (1.9-17 % infection rate) and C. aerophila (0.9-4.8 % infection rate) were found in all examined sites, while cats scored positive for T. brevior (1-14.3 % infection rate) in four sites. Also, T. brevior was here found for the first time in a domestic cat from a mountainous area of Northern Italy. The occurrence of lungworms was statistically related to the presence of respiratory signs and more significant in cats with mixed infection by other lungworms and/or intestinal parasites. Cats living in site C of Central Italy resulted statistically more at risk of infection for lungworms than cats living in the other study sites, while animals ageing less than 1 year were at more risk for troglostrongylosis. Finally, the presence of lungworms was more significant in cats with mixed infection by other lungworms and/or intestinal parasites. These results are discussed under epidemiological and clinical points of views.

Metastrongyloid infection by Aelurostrongylus abstrusus, Troglostrongylus brevior and Angiostrongylus chabaudi in a domestic cat

The "cat lungworm", Aelurostrongylus abstrusus, affects cats worldwide. Recently, other cardio-pulmonary parasites, e.g. Troglostrongylus brevior and Angiostrongylus chabaudi, have been isolated from cats either for the first time or a long time after they were first described. This paper describes the first known mixed infection by A. abstrusus, T. brevior and A. chabaudi in a domestic cat. Biological and epidemiological implications of old and "new" metastrongyloid-caused infections in cats are discussed.

Cardio-Pulmonary Parasitic Nematodes Affecting Cats in Europe: Unraveling the Past, Depicting the Present, and Predicting the Future

Various cardio-pulmonary parasitic nematodes infecting cats have recently been fascinating and stimulating the attention of the Academia, pharmaceutical companies, and veterinary practitioners. This is the case of the metastrongyloids: Aelurostrongylus abstrusus and Troglostrongylus brevior, the trichuroid: Capillaria aerophila (syn. Eucoleus aerophilus), and the filarioid: Dirofilaria immitis. Apparently, these parasites have been emerging in several European countries, thus, gaining an important role in feline parasitology and clinical practice. Under a practical standpoint, a sound knowledge of the biological, epidemiological, and clinical impact of cardio-respiratory parasitoses affecting cats, in addition to a potential risk of introduction, establishment, and spreading of “new” parasites in Europe is mandatory in order to understand the present and future impact for feline medicine and to address new strategies of control and treatment. The purpose of the present article is to review the current knowledge of heartworm and lungworm infections in cats, discussing and comparing past and present issues, and predicting possible future scenarios.

First report of Troglostrongylus brevior in a kitten in Greece

The first case of a natural infestation with Troglostrongylus brevior in a kitten in Greece is described here. A ∼40-day-old stray cat was referred to a private veterinary clinic with signs of respiratory distress. First stage larvae of a metastrongyloid nematode were observed in the wet mount faecal preparation. Despite an anthelmintic treatment, the respiratory signs worsened and the kitten died 2 days later. The larvae in the faeces were identified morphologically and genetically as T. brevior. The present evidence suggests a vertical or direct infestation of the kitten and a severe pathogenic role of T. brevior in young cats. This report expands the recent published cases of troglostrongylosis in domestic cats to a wider geographical distribution and opens new questions on the apparent spreading of T. brevior from wild to domestic hosts.

Feline lungworm Oslerus rostratus (Strongylida: Filaridae) in Italy: first case report and histopathological findings

Oslerus rostratus syn. Anafilaroides rostratus (Strongylida: Filaroididae) is a metastrongyloid transmitted by snails, which localizes in peri-bronchial tissues and in the lung parenchyma of wild as well as domestic cats. In Europe, this nematode has been reported only on two occasions, being diagnosed in cats from Majorca Island and in northern Spain. Here, we describe a case of O. rostratus infection in a necropsied 4-year-old cat in Sicily (southern Italy). At the inspection of lungs, slender and greyish nematodes (four females and two males) were found embedded in the peri-bronchial tissues and in the bronchial walls. Parasites were morphological and molecularly identified as O. rostratus, with their 18S sequences being identical among them and showing a high homology (99%) with those available in public databases. At the histology, nematodes were encapsulated in a pseudo-cystic formation surrounded by an interstitial inflammatory process and fibrous tissue. Lung lesions were mainly represented by peri-luminal fibrosis, hyperplasia and hypertrophy of the bronchial mucosa and glands, respectively. This first record of O. rostratus infection from Italy indicates that this parasite should be included in the differential diagnosis of feline of lungworm infection.

Pathological and histological findings associated with the feline lungworm Troglostrongylus brevior

Troglostrongylus brevior is a neglected feline lungworm species, which has been increasingly reported in the Mediterranean area, although scant data are available on the respiratory alterations it causes in cats. Therefore, we describe the gross and histological lesions of a 20-week old kitten that succumbed due to the onset of a fulminant respiratory failure. At necropsy, a catarrhal exudate was observed in the airways, along with nematodes in the trachea and bronchi. The lungs were processed for histological examination and serial pulmonary sections were performed. A total of 14 nematodes were collected, being all morphologically and molecularly identified as T. brevior. Lungworms were histologically localized within the bronchial lumen, surrounded by an eosinophilic infiltrate. The presence of T. brevior in the airways has been histologically documented for the first time and its life-threatening potential is discussed.