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

Regional distribution of feline lungworm Aelurostrongylus abstrusus in cats from Spain

Aelurostrongylus abstrusus, a respiratory nematode affecting worldwide cats, has different prevalence across Europe. This study aims to evaluate the rates of positivity of this parasite in the different regions of Spain, analyzing fecal samples sent to a reference laboratory for the Baermann-Wetzel technique, between 2017 and 2023. The estimated overall infection rate in Spain was 9.4 %, being the positive cases distributed throughout all climatic regions of the country, highlighting the wide distribution of this parasite. The northwestern region had the highest infection rate (19.5 %) and the central region the lowest (5 %). Winter was the season with the highest detection rate (11.6 %) and young cats (<1 year old) were 5.29 times more likely to be positive than older cats (p < 0.05). These findings highlight the wide distribution of A. abstrusus throughout the different climatic regions of Spain, being important to include it as a differential diagnosis in the investigation of respiratory processes in cats.

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.

Angiostrongylus vasorum, Aelurostrongylus abstrusus, Crenosoma vulpis and Troglostrongylus brevior Infections in Native Slug Populations of Bavaria and Baden-Wuerttemberg in Germany

Angiostrongylus vasorum, Crenosoma vulpis, Aelurostrongylus abstrusus and Troglostrongylus brevior can cause severe cardiovascular and pulmonary symptoms in companion animals and wildlife. Recently, these nematodes were reported to spread within Europe and South America. The reasons behind this are still unknown, but obligate gastropod intermediate host populations might play a role. Therefore, lungworm infections in terrestrial slug populations in selected geographic areas of the Federal States of Bavaria and of Baden-Wuerttemberg, Germany, were studied. In total, 517 slugs (462 Arion spp., 51 Deroceras reticulatum, one Limax maximus, and three unknown slug species) were collected in the summer and autumn seasons, artificially digested and microscopically and molecularly analyzed for the presence of metastrongyloid lungworm larvae. Overall, gastropods showed a prevalence of 11.61% (60/517) for A. vasorum, 1.74% (9/517) for A. abstrusus, 0.77% (4/517) for C. vulpis and 0.97% (5/517) for T. brevior infections, respectively. In Obrigheim (Baden-Wuerttemberg), a hyperendemic focus of canine angiostrongylosis was identified. Here, gastropod infection rates rose from 13.60% (17/125) to 62.96% (34/54) within a few months. In total, 25.61% (84/328) of analysed terrestrial gastropods from Baden-Wuerttemberg were positive for metastrongyloids. In contrast, Bavarian gastropods showed a much lower prevalence of 4.76% (9/189). For the first time, the presence of T. brevior was confirmed for Arion spp. in Baden-Wuerttemberg via molecular analyses. Overall, the current data confirm that canine angiostrongylosis occurs in hyperendemic foci in certain geographic areas with high infection rates in intermediate host populations. As a result, the prevalence for a specific region can rise remarkably within a short period of time. Thus, for a better understanding of lungworm epidemiology in Germany and to protect dogs from angiostrongylosis in hyperendemic foci, it seems mandatory to enhance current efforts on Metastrongyloidea-targeted monitoring on a geographical and time span-related level.

New insights into the distribution of cardio-pulmonary nematodes in road-killed wild felids from Romania

Background

The population of wild felids is large and stable in Romania with many carnivore habitats being protected. Felids can be infected with a wide variety of cardio-pulmonary nematodes and can act as reservoirs of infection for domestic cats. The aim of this study was to evaluate the distribution and species diversity of cardio-pulmonary nematodes in wild felids from Romania.

Methods

A total of 54 wild felids (7 Lynx lynx and 47 Felis silvestris) were legally collected from different locations in Romania and analysed by complete parasitological necropsy. The entire respiratory tract was longitudinally opened and checked for the presence of nematodes. Detected nematodes were collected and morphologically identified to species level.

Results

Two Eurasian lynxes and 29 European wildcats were positive for cardio-pulmonary nematodes. Eurasian lynxes were infected with two species of cardio-pulmonary nematodes, Eucoleus aerophilus and Troglostrongylus brevior, while in wildcats the dominant parasite was E. aerophilus (34.0%) followed by Angiostrongylus chabaudi (23.4%) and T. brevior (14.9%). Dirofilaria immitis and Aelurostrongylus abstrusus were each detected in two wildcats (4.3%).

Conclusions

The present study expanded the epidemiological knowledge on felid cardiopulmonary nematodes in Romania. We confirmed the presence of A. abstrusus in wildcats and a patent infection with T. brevior in Eurasian lynx.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05281-z.

Efficacy of a spot-on combination containing 10% w/v imidacloprid and 1% w/v moxidectin for the treatment of troglostrongylosis in experimentally infected cats

Background

Parasitic bronchopneumonia in domestic cats in Europe, which can manifest with moderate to severe clinical signs, is frequently caused by Troglostrongylus brevior. Data on epizootiological and clinical relevance of cat troglostrongylosis have been published in the last decade but treatment options are still limited. Promising effectiveness data have been generated from clinical cases and field trials for a spot-on formulation containing 1% w/v moxidectin and 10% w/v imidacloprid (Advocate^®, Elanco Animal Health). Therefore, two studies have been conducted to confirm under experimental conditions the efficacy of moxidectin 1% contained in Advocate^® for the treatment of cat troglostrongylosis.

Methods

Sixteen and 20 cats experimentally infected with T. brevior were included in two separate studies, i.e., Study 1 and 2, respectively. Cats were infected with T. brevior third-stage larvae via gastric tube. In both studies cats were randomized to untreated (control, Group 1) and treatment (Group 2) groups. In Study 1 and Study 2, the two groups comprised eight and 10 cats each. Treated cats received Advocate^® spot-on twice at a 4-week interval. The primary efficacy criterion was the number of viable adult T. brevior counted at necropsy. Throughout the trial, the fecal shedding of first-stage larvae (L1) was assessed in treated and untreated control cats.

Results

The experimental model was successful in both studies, as all cats started shedding T. brevior L1 within 25 days post-infection. At necropsy, T. brevior adults were found in 4/8 and 4/10 cats of the control groups in Study 1 and 2, respectively, while none of the treated cats harbored adult worms. The necropsy worm counts in controls did not meet relevant guideline requirements for adequacy of infection, with fewer than six infected cats in the control groups, thus limiting conclusions on treatment efficacy. The fact that 6/8 and 8/10 control cats in Study 1 and 2, respectively, shed L1 up to necropsy while larval shedding ceased in all treated animals after the first treatment provides supporting evidence on the level of efficacy. No remarkable adverse events were recorded in the two studies.

Conclusion

These results indicate that Advocate^® spot-on is a safe and effective option for treating cats infected by T. brevior.

Graphical Abstract

Occurrence of Aelurostrongylus abstrusus in domestic cats in Vilhena, Rondônia, Brazil

Aelurostrongylosis, caused by the metastrongylid nematode Aelurostrongylus abstrusus, is an underestimated feline respiratory disease. Cats infected by A. abstrusus may show subclinical to severe clinical signs. Aelurostrongylus abstrusus has a worldwide distribution. Nevertheless, studies on this parasite in Brazil are scarce, and most have been conducted in the southern regions. This study investigated the occurrence of A. abstrusus in cats in Vilhena, Rondônia, Brazil, from April 2020 to February 2021. Three consecutive individual fecal samples from 101 cats were examined using Baermann and Hoffman tests. Two cats (1.98%) scored positive for A. abstrusus, one with the Baermann examination, and one with the Hoffman technique. No other lungworms were retrieved. The clinicopathological and epizootiological implications are described and discussed.

A Molecular Survey on Neglected Gurltia paralysans and Aelurostrongylus abstrusus Infections in Domestic Cats (Felis catus) from Southern Chile

Gurltia paralysans and Aelurostrongylus abstrusus are neglected metastrongyloid nematode species which infect domestic and wild cats in South American countries and in Chile, but no epidemiological studies on concomitant infections have been conducted in Chile so far. The aim of this study was not only to evaluate the occurrence of concomitant infections, but also to identify epidemiological risk factors associated with of G. paralysans and A. abstrusus infections in urban domestic cats (Felis catus) from Southern Chile. Blood samples from clinically healthy domestic cats from three cities of Southern Chile-Temuco, Valdivia, and Puerto Montt-were analyzed by an experimental semi-nested PCR protocol. A total of 171 apparently healthy domestic cats in Temuco (n = 68), Valdivia (n = 50), and Puerto Montt (n = 53) were sampled and analyzed. A total of 93 domestic cats (54.4%) were positive for G. paralysans, and 34 (19.9%) were positive for A. abstrusus infections. From those animals, 34 (19.9%) were co-infected. Cats positive with G. paralysans were found in all three cities; 47.2% in Puerto Montt, 48% in Valdivia, and 64.7% in Temuco. Levels of infection for A. abstrusus in the population under study were 4% (Valdivia), 10% (Puerto Montt), and 32.4% (Temuco). The present large-scale epidemiological study confirmed the presence of these neglected nematodes in domestic cat populations in Southern Chile, and described the possible risk factors associated with feline gurltiosis and aelurostrongylosis.

The Influence of Temperature on the Larval Development of Aelurostrongylus abstrusus in the Land Snail Cornu aspersum

The metastrongyloid Aelurostrongylus&nbsp;abstrusus has an indirect lifecycle involving gastropod intermediate hosts. The widespread snail Cornu&nbsp;aspersum is an efficient intermediate host of A. abstrusus. As the temperature may influence the developmental rate of metastrongyloids from first (L1) to the third infective larval stage (L3) inside molluscs, this study evaluated the effect of two controlled temperatures on the development of A. abstrusus in C. aspersum. Overall, 300 snails were infected with 500 L1 of A. abstrusus and kept at ∼25 °C. Fifteen days post infection (D15), the overall developmental rate to L3 (0.8%) was assessed in a subset of 20 snails. The remaining gastropods were divided in 2 groups, i.e., 180 still kept at ∼25 °C (G1) and 100 hibernated at ∼4 °C (G2). On D30, the larval development was evaluated in 20 snails from each group, while another batch of 80 snails was selected random from G1 and hibernated at ∼4 °C (G3). The larval developmental rate was determined digesting 20 snails from each of the three groups on D45, D60, and D75. The higher mean developmental rate was registered in G1 (3.8%) compared to G2 (1.9%) and G3 (2.3%), indicating that the development to L3 of A. abstrusus in C. aspersum is positively influenced by the increase of temperature.

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.

First Case of Clinical Cat Aelurostrongylosis in the Brazilian Amazon: Clinical and Molecular Insights

Aelurostrongylus abstrusus is the most important respiratory parasite infecting domestic cats worldwide. Nevertheless, most records and epizootiological data come from Europe, whilst poor and fragmentary information are available for other regions, including the Americas. The present article describes the first description of cat aelurostrongylosis from Amazonia, Brazil. Eighty-one cats, 13 from a shelter and 68 admitted at the Teaching and Research Unit in Veterinary Medicine (UV) at the Federal University of Acre (UFAC), Brazil, were included in the study. For all cats, three faecal samples from consecutive defecations were examined using the Baermann’s technique. Nematode first stage larvae (L1), retrieved in 2/81 (2.5%) samples, were microscopically identified as A. abstrusus and then subjected to a molecular assay able to identify the three most important species of metastrongyloids infecting felids. This test confirmed the A. abstrusus identity in one sample, while the second scored negative. The cat with confirmed aelurostrongylosis showed radiographic changes, i.e., an interstitial pattern, compatible with the infection. The other cat, which scored positive at the Baermann’s examination, was apparently healthy at the physical examination and showed no thoracic alterations. The occurrence of A. abstrusus in domestic cats from Brazilian Amazon is herein demonstrated for the first time. Clinical, epizootiological and molecular implications are discussed.

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 Bravecto® Plus spot-on solution for cats (280 mg/ml fluralaner and 14 mg/ml moxidectin) for the prevention of aelurostrongylosis in experimentally infected cats

Background

The feline lungworm Aelurostrongylus abstrusus affects the lower respiratory tract in cats worldwide. As infections may lead to chronic respiratory changes or even death, preventive treatment in cats with outdoor access is warranted.

Methods

The preventive efficacy of a spot-on solution (Bravecto® Plus spot-on solution for cats, MSD) against cat aelurostrongylosis was evaluated using three different preventive treatment regimes in a negative controlled, randomized and partially blinded laboratory efficacy study with 31 purposed-bred cats. The minimum recommended dose of 2.0 mg moxidectin + 40 mg fluralaner/kg bodyweight was applied once 12 (Group [G]1), 8 (G2) or 4 (G3) weeks before experimental infection with 300 third-stage larvae (L3) of A. abstrusus. Another group served as untreated control (G4). Individual faecal samples were analysed as of day 30 post infection (pi) to monitor larvae excretion. Necropsy was performed at days 47–50 pi. The lungs were examined macroscopically for pathological findings and (pre-)adult worms were counted to assess preventive efficacy.

Results

Beginning at day 32–40 pi, all cats of the control group were constantly shedding larvae of A. abstrusus, whereas only one animal of G1 excreted larvae at several consecutive days. In addition, two cats of G1 and G3 and three of G2 were positive on a single occasion. The geometric mean (GM) of the maximum number of excreted larvae was 7574.29 in the control group compared to 1.10 (G1), 1.19 (G2) and 0.53 (G3), resulting in a GM reduction of > 99.9% in all treatment groups. All lungs of the control animals showed severe or very severe alterations at necropsy, while in 94.44% of the treated cats lung pathology was rated as absent or mild. The GM number of (pre-)adult A. abstrusus retrieved from the lungs was 26.57 in the control group, 0.09 in G1 and 0.00 in G2 and G3. Thus, GM worm count reduction was 99.66% in G1 and 100% in G2 and G3.

Conclusions

A single application of Bravecto® Plus spot-on solution at a dose of 2.0 mg moxidectin + 40 mg fluralaner/kg bodyweight reliably prevents cat aelurostrongylosis for at least 12 weeks.

Felid Cardiopulmonary Nematodes: Dilemmas Solved and New Questions Posed

In the past decade cardiopulmonary nematodes affecting felids have become a core research topic in small animal parasitology. In the late 2000s, an increase in studies was followed by unexpected findings in the early 2010s, which have stimulated research teams to start investigating these intriguing parasites. Prolific scientific debate and exchanges have then fostered field and laboratory studies and epi-zootiological surveys. New data have improved basic and applied knowledge, solved dilemmas and posed new questions. This article discusses the past and present background to felid cardiopulmonary nematodes after the last few years of intense scientific research. New data which have demonstrated the key role of Aelurostrongylus abstrusus and Troglostrongylus brevior in causing respiratory infections in domestic cats, and on the nil to negligible current importance of other species, i.e., Troglostrongylus subcrenatus, Oslerus rostratus and Angiostrongylus chabaudi, are presented. Biological information and hypothesized alternative routes of infection are analysed and discussed. Novel identification and taxonomical data and issues are reported and commented upon. On the whole, recent biological, ecological and epi-zootiological information on felid meta-strongyloids is critically analysed, with the aim to answer outstanding questions, stimulate future studies, and underline new research perspectives.

First record of Hepatozoon spp. in domestic cats in Greece

Feline hepatozoonosis is an emerging disease of domestic and wild felids though there is limited knowledge of this infection, e.g. regarding geographical distribution and parasite species involved. The present study evaluated microscopically and molecularly the occurrence of Hepatozoon spp. in domestic cats from insular (Crete, Mykonos and Skopelos) and continental (prefectures of Attica and Thessaloniki) Greece. Out of 282 cats examined, 72 (25.5 %) scored positive by PCR for Hepatozoon spp. and of them, 9 (12.5 %) showed gamonts on the blood smear microscopic examination. Sequences obtained from 35 of the amplicons proved the presence of two haplotypes of Hepatozoon felis. One, herein called H1 (34/35 amplicons) resulted 100 % identical with H. felis from Italy and isolates from other continents, and ∼98 % similar with a H. felis isolate causing severe clinical signs in Austria. The haplotype H2, found in a cat in Skopelos, had ∼94 % identity with H1, with H. felis isolates from Italy, Israel, Spain, a ∼92 % identity with the isolate from Austria, and ∼94-98 % with isolates from South Africa. These are the first records of H. felis in cat populations from Greece and indicate that the infection may be present at high prevalences in different regions of the country. Furthermore, the results of the molecular and phylogenetic analysis support a recent hypothesis indicating the existence of a species-complex classification for H. felis. Further studies aiming at elucidating the genetic make-up of Hepatozoon populations and possible variations in terms of geographic distribution and clinical relevance are necessary. The importance of a continuous epizootiological monitoring is crucial for the establishment of preventative and control measures protecting the health of cats living in or travelling to enzootic areas.

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.

Troglostrongylus brevior is the dominant lungworm infecting feral cats in Jerusalem

Feline lungworms infect the respiratory tract of wild and domestic cats, causing infection often associated with clinical disease. Until recently, Aelurostrongylus abstrusus has been considered the most relevant species of lungworm, while Troglostrongylus brevior was considered of less significance. Fecal samples of feral cats from Jerusalem, Israel, collected over a year, were examined for first stage lungworm larvae (L1) using the Baermann method. Positive samples were morphologically identified, and their species identity was molecularly confirmed. Forty of 400 (10.0%) cats were lungworm-positive, of which 38/40 (95.0%) shed Troglostrongylus brevior and 6/40 (15.0%) shed Aelurostrongylus abstrusus. Four cats (10.0%) had mixed infections with both lungworm species. L1 shedding was associated with clinical respiratory signs in 11 (19.0%) T. brevior shedding cats of a total of 58 cats manifesting respiratory signs, while 23/342 (6.7%) cats without respiratory signs were L1-positive (p = 0.006). Non-respiratory clinical signs were also found to be more prevalent in L1 shedders (p = 0.012). A young kitten ≤ 4 weeks of age shed T. brevior L1 larvae. DNA sequences of both lungworm species using the ribosomal internal transcribed spacer 2 (ITS2) locus were > 99% similar to other sequences deposited in GenBank, suggesting that T. brevior and A. abstrusus ITS2 sequences are both highly conserved. In conclusion, L1 shedding in feral cats from Jerusalem were mostly caused by T. brevior with only a small proportion involving A. abstrusus, different from many studies from other geographical regions.

Transmammary transmission of Troglostrongylus brevior feline lungworm: a lesson from our gardens

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Transmammary transmission of Troglostrongylus brevior in domestic cats is suggested.

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Snails, rats and lizards play a role in the epidemiology of this feline lungworm.

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Observational parasitology is important in studying events that may occur in small ecological niches around us.

Feline lungworms such as Aerulostrongylus abstrusus and Troglostrongylus brevior are snail-borne pathogens causing respiratory disease in domestic cats. Paratenic hosts such as rodents and reptiles have also been implicated in the epidemiology of these parasites. Although A. abstrusus has been recognized for a long time as the most prevalent lungworm among cats worldwide, T. brevior is of major concern in kittens. Bearing in mind that disease due to T. brevior occurs mainly in pediatric patients younger than 6 months of age, the diagnosis of this parasite in two kittens presenting severe respiratory disease from the garden of one of the authors inspired us to investigate the potential routes of transmission for T. brevior in domestic cats. Of the three queens (A, B and C) that delivered kittens (n = 8), only cat A was positive for T. brevior, presenting her two kittens severe respiratory clinical signs, which lead to the exitus in one of them, 18 days of age. In addition, three kittens, the offspring of queen B, turned to be positive at the coprological examination after suckling from queen A, whereas those from queen C (that suckled only on their own mother) remained negative. A series of coprological, histological and molecular tests were conducted to confirm the presence of T. brevior in the patients as well as in the other cats cohabiting the same garden. Adult nematodes were retrieved from the trachea and bronchi of the dead kitten (kitten 1A), and larvae at the histology of the lung and liver parenchyma associated with bronco pneumonitis and lymphocytic pericholangitis, respectively. Cornu aspersum (n = 60), Eobania vermiculata (n = 30) snails (intermediate hosts) as well as lizards and rats (potential paratenic hosts) were collected from the same garden and processed through tissue digestion and molecular detection. Troglostrongylus brevior larvae were recovered through tissue digestion from two C. aspersum (3.33 %) and it was confirmed by PCR-sequencing approach, which also detected T. brevior DNA in the liver and lungs of one rat and in the coelomatic cavity of one gecko lizard. During the COVID-19 lockdown, when scientists spent more time at home, we grasp the opportunity to decipher T. brevior biology and ecology starting in a small ecological niche, such as the garden of our house. Data herein presented led us to suggest: i) the transmammary transmission of T. brevior in domestic cats; ii) the role of intermediate and paratenic hosts (including reptiles) in the epidemiology of the infection which they transmit; as well as iii) the importance of observational parasitology in studying any event that certainly occurs in small ecological niches, as it could be in our home gardens.

Feline lungworms in Greece: copromicroscopic, molecular and serological study

Aelurostrongylus abstrusus (Nematoda, Metastrongyloidea) causes verminous pneumonia in cats worldwide. This study evaluated the seroprevalence of A. abstrusus antibodies in 220 stray and free-roaming cats from insular (Mykonos, Crete, Skopelos) and continental (Thessaloniki, Attica) Greece. The results were compared with morphological and biomolecular identification of first-stage larvae (L1) in faeces. Positive cats were observed in all 5 areas: 13/97 (13.4%), 1/32 (3.1%), 7/26 (26.9%), 3/18 (16.7%) and 5/47 (10.6%) cats tested positive for A. abstrusus L1 by Baermann examination, and 33/97 (34.0%), 7/32 (21.9%), 6/26 (23.1%), 3/18 (16.7%) and 11/47 (23.4%) were seropositive, in Mykonos, Crete, Skopelos, Thessaloniki and Attica, respectively. Troglostrongylus brevior L1 were found in 12/97 (12.4%), 3/26 (11.5%) and 2/47 (4.3%) cats from Mykonos, Skopelos and Attica respectively. Six of the 220 cats (2.7%), i.e. 4/97 (4.1%) from Mykonos and 2/26 (7.7%) from Skopelos, shed L1 of both A. abstrusus and T. brevior. Sixty samples were ELISA-positive (27.3%, 95% CI: 21.5-33.7%), of which 21 (35%) tested copromicroscopically positive (19 monospecific infections and 2 mixed with Troglostrongylus brevior), and 5 were positive for T. brevior L1 only. Among seronegative cats (n = 140), L1 of A. abstrusus were additionally detected in 8 (5.7% out of 140) cats (i.e. 4 monospecific infections and 4 mixed with T. brevior), and in 6 (4.3% out of 140) cats, L1 of T. brevior as monospecific infection were detected. This study confirms the presence of lungworms in Greece and suggests that the number of cats infected with/exposed to metastrongylids is higher than detected by faecal examinations.

Intermediate gastropod hosts of major feline cardiopulmonary nematodes in an area of wildcat and domestic cat sympatry in Greece

Background

The metastrongyloid nematodes Aelurostrongylus abstrusus, Troglostrongylus brevior and Angiostrongylus chabaudi are cardiopulmonary parasites affecting domestic cats (Felis catus) and wildcats (Felis silvestris). Although knowledge on these nematodes has been improved in the past years, gaps in our knowledge of their distribution and role of gastropods as intermediate hosts in Europe still exist. This study reports on the presence of these nematodes and their intermediate hosts in an area in Greece where domestic cats and wildcats occur in sympatry.

Methods

Terrestrial gastropods were collected in the field and identified morphologically and by mitochondrial DNA-sequence analysis. Metastrongyloid larvae were detected by artificial digestion, morphologically identified to the species and stage level and their identity was molecularly confirmed.

Results

Aelurostrongylus abstrusus was found in the snails Massylaea vermiculata and Helix lucorum, T. brevior in the slug Tandonia sp., and A. chabaudi in the slug Limax sp. and the snails H. lucorum and M. vermiculata.

Conclusions

To the best of our knowledge this study provides the first reports of (i) terrestrial gastropods being naturally infected with A. chabaudi, (ii) T. brevior naturally infecting terrestrial gastropods in Europe, and (iii) A. abstrusus naturally infecting terrestrial gastropods in Greece. Furthermore, the present study describes for the first time developmental stages of A. chabaudi and T. brevior in naturally infected gastropods. The biological characteristics of various intermediate gastropod hosts that could influence the distribution and expansion of feline cardiopulmonary nematodes are discussed, along with epizootiological implications and perspectives.

An initial coprological survey of parasitic fauna in the wild Amur leopard (Panthera pardus orientalis)

The Amur leopard, one of nine recently recognized subspecies of leopard, is still the most threatened by a stochastic procession of extinction. Evaluation of the potential danger to the conservation of the Amur leopard originating from disease urgently needs to be studied. Unfortunately, research on the potential risk to Amur leopards caused by disease is rare. In terms of parasitic diseases that affect this species, even basic data for parasitic fauna are absent. The aim of this study is to acquire this knowledge to improve the general understanding of Amur leopard parasites. Seven parasite species, including 3 nematodes (Toxocara cati, a capillarid-type parasite, and a Metastrongyloidea-type parasite), 2 cestodes (Spirometra sp. and Taenia sp.), 1 trematode (Paragonimus sp.), and 1 protozoan (Cystoisospora felis), were found in this research. Toxocara cati occurred most frequently, followed by Spirometra sp.

The effect of the hibernation on the larval development of Troglostrongylus brevior in the land snail Cornu aspersum

Troglostrongylus brevior, a lungworm affecting wild felids, has been increasingly reported in domestic cats from Europe. Troglostrongylosis is a relevant disease that may result in a potentially life-threatening bronchopneumonia, especially in kittens. The life cycle of T. brevior is indirect with terrestrial gastropods acting as intermediate host. The widely distributed spread land snail Cornu aspersum (former Helix aspersa) is competent for T. brevior development and may transmit the nematode in natural conditions. The present study evaluated the larval development of T. brevior in C. aspersum at two different environmental temperature conditions, with a focus on the effect of hibernation. One hundred and seventy snails were infected with 500 first stage larvae (L1) of T. brevior and kept in vivaria at 25 ± 2 °C. Fifteen days post infection (p.i.), 20 specimens were digested to evaluate the overall larval developmental rate from L1 to L3 (2.5 % on days 15 p.i.) and then the snails were divided in two groups, i.e. G1 kept at 25 ± 2 °C and G2 that were hibernated at 4 ± 2 °C. The developmental rate of T. brevior was evaluated in these groups on 30 and 60 days p.i. by snail digestion at each time-point. An additional batch of 40 snails (G2-1) was hibernated on D15 and digested on D60. Larvae recovered were morphologically and morphometrically examined. The infective third larval stage (L3) was detected in the muscular foot of C. aspersum at different rates depending on the environmental temperature. In particular, T. brevior showed a higher developmental rate in hibernated snails (G2: 6.9 % and 14.1 % on days 30 and 60 p.i; G2-1: 4%; G2 + G2-1 overall mean percentage: 9%) compared to non-hibernated snails (G1: 4% and 5.2 % on days 30 and 60 p.i.), indicating that lower temperatures may positively influence the developmental in C. aspersum. These data are suggestive for a seasonal pattern of T. brevior infections under field conditions, with snails containing higher parasitic burdens after their natural hibernation occurring in winter. Studies on the larval development of T. brevior in other mollusc species in field surveys evaluating differences in developmental rates and transmission patterns in different seasons are warranted.

Efficacy of imidacloprid 10%/moxidectin 1% spot-on formulation (Advocate®) in the prevention and treatment of feline aelurostrongylosis

Background

In three randomized, controlled laboratory efficacy studies, the efficacy in the prevention of patent infections of a topical combination of imidacloprid 10%/moxidectin 1% (Advocate® spot-on formulation for cats, Bayer Animal Health GmbH) against larval stages and immature adults of Aelurostrongylus abstrusus, as well as the treatment efficacy of a single or three monthly treatments against adult A. abstrusus, were evaluated.

Methods

Cats were experimentally inoculated with 300–800 third-stage larvae (L3). Each group comprised 8 animals and the treatment dose was 10 mg/kg bodyweight (bw) imidacloprid and 1 mg/kg bw moxidectin in each study. Prevention of the establishment of patent infections was evaluated by two treatments at a monthly interval at three different time points before and after challenge infection. Curative efficacy was tested by one or three treatments after the onset of patency. Worm counts at necropsy were used for efficacy calculations.

Results

In Study 1, the control group had a geometric mean (GM) of 28.8 adult nematodes and the single treatment group had a GM of 3.4 (efficacy 88.3%). In Study 2, the control group had a GM of 14.3, the prevention group had a GM of 0 (efficacy 100%), while the treatment group had a GM of 0.1 (efficacy 99.4%). In Study 3, the GM worm burden in the control group was 32.6 compared to 0 in all three prevention groups (efficacy 100% for all of those groups).

Conclusions

The monthly administration of Advocate® reliably eliminated early larval stages and thereby prevented lung damage from and patent infections with A. abstrusus in cats. Regarding treatment, a single application of Advocate® reduced the worm burden, but it did not sufficiently clear the infection. In contrast, three monthly treatments were safe and highly efficacious against A. abstrusus.

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.

Effect of different temperatures on survival and development of Aelurostrongylus abstrusus (Railliet, 1898) larvae

Aim of the study was to get in-depth information on Aelurostrongylus abstrusus first-stage larvae (L1s) survival at different temperatures and to assess the capability of these larvae to develop into the third infective stage (L3s). Faeces of a naturally infected cat were split into two aliquots: the first was divided in subsamples assigned to four groups (F1-F4); from the second aliquot, L1s were extracted by Baermann technique, suspended in water and divided into four groups (W1-W4). Groups were stored at different temperatures (F1/W1 -20 ± 1°C; F2/W2 +4 ± 1°C; F3/W3 +14 ± 1°C; and F4/W4 +28 ± 1°C) and L1s vitality assessed every seven days. The capability of L1s stored in water to develop into L3s in snails was evaluated at the beginning and every 21 days. The L1s of W2 and F2 groups remained viable for a longer period (231 and 56 days, respectively) compared to those of other groups. The capability of L1s to moult into L3s in snails showed a decreasing trend; the group W2's L1s maintained the capability to moult into L3s for the longest time (day 189) compared to the other groups. The time of survival of A. abstrusus L1s is influenced by temperature. However, the species seems to be more resistant to temperature variations than other feline lungworms, and this may explain its wider distribution across Europe.

Efficacy of a moxidectin/imidacloprid spot-on formulation (Advocate®) for the treatment of Troglostrongylus brevior in naturally infected cats in a field study in Greece

Background

Troglostrongylus brevior is a lungworm of wild felids that recently has been recognized as agent of severe respiratory disease in domestic cats in Mediterranean and Balkan countries. Nevertheless, the information on treatment options for feline troglostrongylosis is still poor. The aim of this pilot field trial was to evaluate the efficacy of the spot-on formulation containing 1% w/v moxidectin and 10% w/v imidacloprid (Advocate^® spot-on solution for cats, Bayer Animal Health GmbH) in the treatment of T. brevior infection in naturally infected cats in Greece.

Methods

The trial was a negative control, multicentre, clinical efficacy study conducted according to the standards of Good Scientific Practice (GSP). Sixteen cats in two study sites, naturally infected with T. brevior, were allocated to an untreated control group (G1, n = 8) or a treatment group (G2, n = 8), according to a randomization list. Animals assigned to G2 were treated with Advocate^® for cats on days 0 and 28 at the recommended dose rate and animals assigned to G1 received a rescue treatment with the same product on days 56 and 84. Efficacy was assessed on days 28 and 56 in G2 and on days 84 and 112 in G1 by faecal larval counts. The primary efficacy criterion was the absence of T. brevior first-stage larvae (L1) following treatment. Other efficacy parameters were the quantitative comparison of L1 presence before (baseline) and after one or two treatments in both groups.

Results

All G2 cats were negative for T. brevior L1 at the first post-treatment evaluation (100% efficacy) while G1 cats were persistently shedding L1. The difference of the mean number of L1 per gram between G2 and G1 was statistically significant (P < 0.001). All G1 cats were negative (100% efficacy) for T. brevior L1 at the first post-rescue-treatment evaluation. Therefore, treatment efficacy at study completion was 100% in both groups in terms of stopping the L1 shedding in the faeces of the animals. No adverse effects were observed during the study.

Conclusions

These results indicate that Advocate^® spot-on solution for cats represents an option for treating cats naturally infected with T. brevior.

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.

Comparison of clinical and imaging findings in cats with single and mixed lungworm infection

OBJECTIVES

This study has compared clinical and imaging features in 52 cats naturally infected by respiratory nematodes Aelurostrongylus abstrusus, Troglostrongylus brevior and Capillaria aerophila, and in both monospecific and mixed infections.

METHODS

Medical records of cats with a lungworm disease were retrospectively reviewed. Cats with clinical examination findings, haematobiochemical analysis and thoracic radiography were included in the study and clinical and radiographic scores were assigned. For eight cats CT of the thorax was also available and analysed. A statistical analysis was performed to investigate the potential correlation between clinical and radiographic score, and to evaluate the effect of age, sex and infection on clinical and radiographic severity.

RESULTS

Monospecific infections by A abstrusus (32/52), T brevior (6/52) and C aerophila (5/52) and coinfections by T brevior/ A abstrusus (7/52), T brevior/ C aerophila (1/52) and A abstrusus/ C aerophila (1/52) were diagnosed. Cats with mixed infections showed higher clinical scores compared with cats with monospecific parasitoses ( P <0.05), while no differences were observed for radiographic scores. No correlation between clinical and radiographic scores was found (rs = 0.50), and these scores were not affected by patient age or sex. CT, performed on cats infected with A abstrusus, T brevior or A abstrusus/T brevior, provided additional information in cats with mild radiographic signs.

CONCLUSIONS AND RELEVANCE

This study indicates that clinical parameters may be more severe in mixed infections than in monospecific parasitoses. A significant correlation between clinical and radiographic score was not detected, while several subclinically infected cats showed radiographic changes. In cats with mild-to-moderate lung patterns, the ventrodorsal/dorsoventral projection showed lesions that are not visible in the lateral projections, especially in the caudal lobes.

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.

Pilot study evaluating the efficacy of a topical formulation containing emodepside and praziquantel in the treatment of natural feline troglostrongylosis

Background

Troglostrongylus brevior, a lungworm usually affecting wild felids, has been recently recorded in a number of cases in domestic cats, mainly in Mediterranean areas. Although feline troglostrongylosis is a severe and life-threatening disease, especially in young cats, treatment options are very limited. The present study evaluated the efficacy and safety of a spot-on formulation containing emodepside 2.1% and praziquantel 8.6% (Profender^®, Bayer), which is licensed for treatment of the more common cat lungworm Aelurostrongylus abstrusus, for the treatment of natural troglostrongylosis.

Methods

Sixteen cats enrolled in the study were 1:1 allocated to two groups, i.e. Group T, treated with Profender^® spot-on on days 0 and 14 (± 2) at the recommended clinical dose, and Group C which remained untreated. After study completion, the control cats received two rescue treatments with Profender^® on days 28 (± 2) and 42 (± 2). The primary efficacy criterion was the absence of T. brevior L1 following treatment. Other efficacy parameters were the quantitative comparison of L1 presence before (baseline) and after treatment in both groups, and the comparison of clinical signs pre- and post-treatment.

Results

In terms of stopping larval shedding, Profender^® showed an efficacy of 97% and 97.5% (arithmetic and geometric means, respectively) for group T, 97.1% and 98.5% for group C after one administration, and 100% for both groups after two doses. Overall, 12 cats showed clinical signs related to T. brevior. Specifically, 9 were clinically affected before treatment while clinical signs appeared after the first treatment in 3 cats. At the end of the study, all symptomatic cats fully recovered with the exception of 3 cats that showed clinical signs similar to those observed at the pre-treatment examination at the end of the study.

Conclusions

This study shows that Profender^® is effective against T. brevior.

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.

Feline gastrointestinal parasitism in Greece: emergent zoonotic species and associated risk factors

BACKGROUND

Feline gastrointestinal parasitism constitutes an issue of concern for veterinarians since parasites are widespread and affect animals' health and welfare. Furthermore, some of these pathogens have zoonotic potential. To provide detailed data on the current epizootiology of feline endoparasitism, a multicentric survey was conducted during 2016.

METHODS

Faeces from 1150 cats were collected from all regions of Greece and examined by sedimentation and flotation techniques. Possible risk factors including gender, age, ownership status, living conditions and co-infections with other parasites were assessed using binary regression models for each one of the most prevalent parasites.

RESULTS

The overall gastrointestinal parasite prevalence in cats was 50.7%. The study population consisted of cats of both sexes, different age groups, ownership status and living conditions. A total of 10 gastrointestinal parasitic species were detected and up to 5 different parasites were isolated in the same faecal sample. The most frequently identified parasites were Toxocara cati (n = 278; 24.2%), followed by Cystoisospora spp. (n = 189; 16.4%), Ancylostomatidae (n = 186; 16.2%), Aelurostrongylus abstrusus (n = 40; 3.5%), Giardia spp. (n = 26; 2.3%), Joyeuxiella pasqualei (n = 14; 1.2%), Capillaria aerophila (n = 8; 0.7%), Dipylidium caninum (n = 3; 0.2%), Toxascaris leonina (n = 2; 0.1%) and Troglostrongylus brevior (n = 2; 0.1%). The occurrence of co-infections was 11.6%. Concerning risk factors, the likelihood of T. cati infection was higher for female cats living outdoors and for cats being infected with Cystoisospora spp. In the same frame, young, stray, male and free of A. abstrusus cats were more likely to be infected with Cystoisospora spp. Correspondingly, stray, infected with Giardia spp. but free of Cystoisospora spp. cats were more likely to be infected with Ancylostomatidae. Regarding A. abstrusus infection, a higher probability was reported for cats living outdoors and for cats free of Cystoisospora spp., while Giardia spp. infections were more common in young and co-infected with Ancylostomatidae animals.

CONCLUSIONS

The prevalence of parasitized cats in Greece was high and thus consideration should be paid to control the risk factors, to implement targeted preventive antiparasitic treatments and educate cat owners on the value of prevention for the health and welfare of their cats.

Clinical evaluation of outdoor cats exposed to ectoparasites and associated risk for vector-borne infections in southern Italy

BACKGROUND

Cats can be carriers of infected arthropods and be infected with several vector-borne pathogens (VBP) but there is limited knowledge about their pathogenic role in cats.

RESULTS

A cross-sectional controlled study investigated the clinical status and antibody (Bartonella henselae, Rickettsia conorii, Ehrlichia canis, Anaplasma phagocytophilum, Babesia microti and Leishmania infantum) and/or blood PCR (Mycoplasma spp., Bartonella spp., Rickettsia spp., Ehrlichia/Anaplasma spp., piroplasmids, L. infantum, Hepatozoon felis) prevalence in 197 cats. Outdoor cats lacking ectoparasiticide treatment or hosting ectoparasites (study group [SG], n = 134) and indoor cats treated against ectoparasites (control group [CG], n = 63) were enrolled. Clinical data and retroviral co-infections were compared between the two groups. Multivariable analysis tested associations between variables and VBP exposure. Lymphadenia, stomatitis, and various haematological abnormalities were statistically more frequent in SG. Antibodies against R. conorii, B. henselae, A. phagocytophylum, B. microti, E. canis and L. infantum were detected. Bartonella henselae, Bartonella clarridgeiae, Mycoplasma haemofelis, "Candidatus Mycoplasma haemominutum" and "Candidatus Mycoplasma turicensis" DNA were identified. Very high antibody (87.8%) and PCR (40.1%) positivity to at least one pathogen were detected and were significantly higher in SG. Co-infections were confirmed in about one-third of the cats and were more frequent in SG cats. Molecular and overall (antibody and PCR) positivity to Bartonella and antibody positivity to R. conorii were higher in SG. Multivariable analysis found significant associations of Bartonella spp. infection with Feline Immunodeficiency Virus (FIV) infection and increased globulins, and of Mycoplasma spp. infection with adult age, FIV infection, anaemia, and increased creatinine.

CONCLUSIONS

A very high prevalence of exposure to zoonotic VBP was found in cats, with Rickettsia and Bartonella infections being most prevalent. Some risk factors were documented namely for Mycoplasma spp. and Bartonella spp. The lifestyle of cats is clinically relevant and requires specific preventative measures to protect their health.

Troglostrongylus brevior: a feline lungworm of paediatric concern

The immature immune system of cats in their paediatric age (i.e., first six months of life) favours the establishment of infectious respiratory tract diseases mainly caused by well recognized viruses and bacteria species. Conversely, lungworm infections are less investigated during respiratory disorders in kittens. In the last decade, Troglostrongylus brevior has been found affecting the respiratory tract of cats, along with the better-known Aelurostrongylus abstrusus. Given the scant data available on the epidemiology of feline troglostrongylosis, faecal samples from 575 domestic animals living in three Italian municipalities (i.e., Bari, Messina and Siena) were screened for lungworm infection by Baermann and molecular tecniques. Animals were grouped according to their age as ≤6 months (i.e., paediatric patients), 6-24 months, or >24 months. Paediatric cats were further sub-divided in infant (2-6 weeks), weanling (6-12 weeks) and juvenile (3-6 months). Of the 575 animals tested, 241 (42.0%) were younger than 6 months, 188 (33%) were 6-24-month-old and 146 (25%) were older than 24 months. Lungworm infection was diagnosed in 84 (14.6%) of the examined cats. Of the 49 (20.3%) paediatric animals positive for lungworms, T. brevior was the nematode species most frequently diagnosed (n = 44; 89.8%), followed by A. abstrusus (n = 2; 4.1%), and three cats (6.1%) were co-infected by both species. The diagnosis of T. brevior infection was significantly associated with animals aging ≤6 months (18.2%; P < 0.01) than elder cats. Indeed, the prevalence of infection by T. brevior decreased in animals aging 6-24 months (3.2%) being not detected in cats older than two years. Results of this study indicate that paediatric cats are at higher risk of T. brevior infection compared to adults (P < 0.01).

Endoparasites of Wild Mammals Sheltered in Wildlife Hospitals and Rehabilitation Centres in Greece

Wildlife parasitic diseases represent an important field of investigation as they may have a significant impact on wild animals’ health and fitness, and may also have zoonotic implications. This study aimed to investigate the occurrence of endoparasites in wild mammals admitted to wildlife hospitals and rehabilitation centres in Greece. Sixty-five animals belonging to 17 species and originated from various areas of continental and insular Greece were included in the survey. The most numerous animal species examined were hedgehogs (n = 19), red foxes (n = 16), and European roe deer (n = 6). Faecal samples were collected individually and examined by floatation and sedimentation method. Parasites were found in 46 (70.7%) of the animals. Most parasites found in canids, felids, and ruminants are of great relevance to the domestic animals’ health and some of them are also of zoonotic importance. To the best of the author’s knowledge, this is the first report of endoparasites in hedgehogs, roe deers, fallow deers, badgers, and bats, and the first report of the pulmonary nematode Troglostrongylus brevior in a wild cat in Greece. The significance of the parasites found in each animal species in regard to their health and their relevance to domestic animals and human health is discussed.

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.

Occurrence and zoonotic potential of endoparasites in cats of Cyprus and a new distribution area for Troglostrongylus brevior

The present study investigated for the first time the occurrence of pulmonary and intestinal parasites of cats in Cyprus. Cats from five districts of Cyprus (Lefkosia, Lemesos, Larnaka, Pafos and Ammochostos) were examined by classical parasitological methods and the identity of lungworm larvae, whenever present, was confirmed by PCR-coupled sequencing. A total of 185 cats, 48 living exclusively indoors and 137 with outdoor access, were included in the study. Parasites were found in 66 (35.7%) of the examined cats, i.e. Toxocara cati (12%), Cystoisospora rivolta (12%), Joyeuxiella/Diplopylidium spp. (7%), Giardia spp. (6.5%), Troglostrongylus brevior (5%), Cystoisospora felis (2.5%), Aelurostrongylus abstrusus (2%), Taenia spp. (0.5%) and Dipylidium caninum (0.5%). Mixed infections were recorded in 18 cats. Cats that lived exclusively indoors or had received an antiparasitic treatment in the last 6 months were less likely to be infected (p < 0.05). Moreover, cats younger than 1 year old were more likely to shed first-stage larvae of T. brevior (p = 0.04). The present study shows that cats in Cyprus are infected at a high percentage by a variety of parasites that potentially affect their health and also, in some cases (i.e. T. cati, D. caninum, Giardia spp.), may have an impact on human health. Moreover, it was revealed that T. brevior, a lungworm of emerging significance, is present on the island, rendering Cyprus the easternmost distribution border of this parasite in Europe to date.

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.

Larval development of Angiostrongylus chabaudi, the causative agent of feline angiostrongylosis, in the snail Cornu aspersum

Nematodes of the Angiostrongylidae family, such as Angiostrongylus vasorum and Angiostrongylus cantonensis, may cause potentially life-threatening diseases in several mammal species. Alongside these well-known species, Angiostrongylus chabaudi has been recently found affecting the cardiopulmonary system of domestic and wild cats from Italy, Germany, Greece, Romania and Bulgaria. Nonetheless, significant gaps in the understanding of A. chabaudi epidemiology include the lack of information of species acting as intermediate host and of the morphological description of larval stages. Cornu aspersum (n = 30) land snails were infected with 100 first-stage larvae of A. chabaudi collected from a naturally infected wildcat in Romania. Larvae at different developmental stages were found in 29 out of 30 (96·7%) infected snails and a total of 282 (mean 9·8 ± 3·02 larvae per each specimen) were collected from the gastropods. Here we demonstrate that A. chabaudi develops in snails and report C. aspersum as potential intermediate host for this parasitic nematode. Findings of this study are central to understand the ecological features of feline angiostrongylosis and its epidemiology within paratenic and intermediate hosts.

Lungworms and gastrointestinal parasites of domestic cats: a European perspective

With the exception of Aelurostrongylus abstrusus, feline lungworms have been poorly studied. Information on their distribution is patchy and mostly limited to case reports. In this study, the occurrence of feline lungworms and co-infecting gastrointestinal parasites has been investigated in 12 European countries (i.e. Austria, Belgium, Bulgaria, France, Greece, Hungary, Italy, Portugal, Romania, Spain, Switzerland and the United Kingdom). An average of 10 domestic cats, with regular outdoor access, was sampled each month for 12months, and freshly passed faeces were collected. Stools were processed using a McMaster assay and a quantitative Baermann-Wetzel method. Animals positive for lungworms and/or gastrointestinal parasites were treated with a formulation containing fipronil, (S)-methoprene, eprinomectin, and praziquantel (Broadline®, Merial), and re-sampled 28days post-treatment. The association between lungworm infection and risk factors was analysed using statistical medians/means and the efficacy of the treatment against each lungworm species was assessed. Of 1990 cats sampled, 613 (30.8%) were positive for at least one parasite, while 210 (10.6%) were infected by lungworms. The prevalence of lungworm infection varied between the sampled sites, with the highest recorded in Bulgaria (35.8%) and the lowest in Switzerland (0.8%). None of the cats from Austria or the United Kingdom were infected by lungworms. Aelurostrongylus abstrusus was the species most frequently detected (78.1%), followed by Troglostrongylus brevior (19.5%), Eucoleus aerophilus (14.8%) and Oslerus rostratus (3.8%). The overall efficacy of the treatment was 99% for A. abstrusus and 100% for T. brevior, O. rostratus and E. aerophilus. Data presented provide a comprehensive account of the diagnosis, epidemiology and treatment of feline lungworms in Europe, as well as of the occurrence of co-infections by gastrointestinal parasites.

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.

Detection of specific antibodies in cats infected with the lung nematode Aelurostrongylus abstrusus

Feline aelurostrongylosis, caused by the metastrongylid nematode Aelurostrongylus abstrusus, is an underestimated respiratory parasitosis. Its diagnosis currently mainly relies on the isolation of first stage larvae from fresh faecal samples. The aim of our study was to develop a serological test for the detection of specific antibodies against A. abstrusus by ELISA. We used recombinant major sperm protein (MSP) of the bovine lungworm Dictyocaulus viviparus as detection antigen and evaluated two different ELISA plates (Maxisorp and Immobilizer™ Amino-plate, Nunc Roskilde, Denmark) with two different enzyme systems [alkaline phosphatase (AP) and horseradish peroxidase (HRP)]. Sera from cats experimentally (n=54) and naturally (n=17) infected with A. abstrusus and from randomly selected cats with different medical issues (n=160) were used to determine sensitivity and specificity. Furthermore, cross-reactions were evaluated using sera from cats naturally (n=71) and experimentally (n=8) infected with different nematodes. A sensitivity of 100% was obtained with sera from experimentally infected cats at 10 weeks post infection using MSP on the Immobilizer™ Amino-plate with HRP, while it ranged between 90.5 and 95.2% in the other ELISA set-ups. Using sera from naturally infected cats, a sensitivity of 88.2% (95% confidence interval: 63.6-98.5%) was achieved in all four set-ups. The specificity was 85.2-94.4% in sera from uninfected cats prior to experimental infection and 68.1-90% in randomly selected cats depending on the plate and enzyme system. The number of seropositive cats increased over time post infection. Serological follow-up showed a decrease of antibody levels within 30days after anthelmintic treatment. Seropositive reactions were observed with sera from stray cats naturally infected with Toxocara cati, Capillaria sp., hookworms and Taeniidae; however, coproscopic false negative A. abstrusus findings cannot be excluded. The serological detection of specific antibodies against A. abstrusus using ELISA requires a single serum sample and therefore represents a valid alternative for reliable individual diagnosis of A. abstrusus in cats and facilitates mass screening, overcoming the usually difficult collection of cat faeces.

Updates on feline aelurostrongylosis and research priorities for the next decade

Feline aelurostrongylosis, caused by the metastrongyloid nematode Aelurostrongylus abstrusus, is an important gastropod-borne parasitic lung disease in cats. Infection with A. abstrusus is widespread globally, but the increasing awareness of this parasite and the advent of more sensitive diagnostics have contributed to the apparent increase in its prevalence and geographic expansion. Clinical features may range in severity from subclinical to life-threatening respiratory disease. Parasitological standard techniques, such as visualization of the nematode first larval stage in faecal and respiratory (bronchial mucus or pleural fluid) samples, remain the mainstays of diagnosis. However, diagnosis is evolving with recent advances in serological and molecular testing, which can improve the time to initiation of effective anthelmintic therapy. Despite numerous anthelmintics that are now available as treatment options, the role of host immunity and lifestyle factors in selecting cats that may benefit from more targeted anthelmintic prophylaxis or treatment practice remains unclear and is likely to guide therapeutic choices as newer data become available. This review summarizes the biology, epidemiology, pathophysiology, diagnosis and treatment options currently available for feline aelurostrongylosis.

Aelurostrongylus abstrusus in wild felids of South Africa

The increasing interest on respiratory nematodes of domestic cats (Felis silvestris catus) has recently stimulated several studies on their epidemiology and geographic distribution. At the same time, there are still important gaps in our knowledge of the infections caused by respiratory nematodes in wild felids. The present study investigated the occurrence of pulmonary parasites in wild hosts housed in sanctuaries and protected areas of South Africa. Faecal samples collected from seven species of wild felids living in three study sites were copromicroscopically and genetically examined. Of twenty-one samples six, i.e. three from caracals (Caracal caracal), two from lions (Panthera leo) and one from a serval (Leptailurus serval), scored positive for the metastrongyloid Aelurostrongylus abstrusus at copromicroscopic and/or molecular tests. No other lungworms were recorded. The occurrence of the cosmopolitan cat lungworm A. abstrusus in wild hosts has been so far questioned. Importantly, the present findings represent an unequivocal evidence of the capability of A. abstrusus to infect some species of wild felids. Further studies are warranted to understand the epidemiological patterns of lungworms in wild and domestic felids, and to better investigate the impact of these parasitoses on health and welfare of wild animals.

First evidence of the European wildcat (Felis silvestris silvestris) as definitive host of Angiostrongylus chabaudi

Angiostrongylus chabaudi (Strongylida, Angiostrongylidae) is a parasitic nematode described for the first time last century from the pulmonary arteries of six European wildcats (Felis silvestris silvestris) in central Italy. Since then, this parasite remained practically unknown until recently, when immature A. chabaudi have been reported from one wildcat in Germany and two domestic cats (Felis silvestris catus) in Italy. The present report describes the first record of A. chabaudi in Greece and, most importantly, the first known case of patent infection by A. chabaudi. The necropsy of a road-killed F. s. silvestris found near the lake Kerkini, in the municipality of Serres (Macedonia, Greece), revealed the presence of nematodes of both sexes in the right ventricle and the pulmonary artery of the heart. All parasites were mature adults and numerous eggs were present in the uteruses of females. The morphological characteristics of the parasites were consistent with those of A. chabaudi. Moreover, Angiostrongylus-like first stage larvae (L1) were present in the faeces of the animal that was negative for any other cardio-pulmonary parasite. Genetic examination of adult parasites and L1 confirmed the morphological identification as A. chabaudi. Histopathological examination of the lungs showed severe, multifocal to coalescing, chronic, interstitial granulomatous pneumonia due to the presence of adult parasites, larvae and eggs. These findings demonstrate for the first unequivocal time that this nematode reproduces in the European wildcat which should be ultimately considered a definitive host of A. chabaudi. Finally, the L1 of A. chabaudi are described here for the first time, opening new prospects for further studies on this neglected parasite.