Diagnosis and risk factors of Aelurostrongylus abstrusus (Nematoda, Strongylida) infection in cats from Italy

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.

Molecular prevalence, phylogenetic characterization, and epidemiological risk factors of pulmonary nematodes in domestic cats in Türkiye

Aelurostrongylus abstrusus, Oslerus rostratus, and Troglostrongylus brevior are nematodes found in the respiratory system of domestic cats and cause a variety of symptoms. All three parasites use the same hosts and niches, and the morphological measurements of their L1s excreted in faeces overlap with each other. In this study, 300 cats brought to Ondokuz Mayıs University Veterinary Teaching Animal Hospital were screened for lungworms by morphological measurements and molecular analyses. The prevalence of the lungworms was found as 1.33% (4/300) for A. abstrusus, 0.66% (2/300) for O. rostratus, and 0.33% (1/300) for T. brevior. Molecular identification of A. abstrusus, T. brevior, and O. rostratus in domestic cats was carried out for the first time in Türkiye within the present study. This study also reveals the risk factors of lungworm positivity in domestic cats in Türkiye.

Diagnostic challenges for Aelurostrongylus abstrusus infection in cats from endemic areas in Italy

BACKGROUND

The lungworm Aelurostrongylus abstrusus infects wild and domestic feline species worldwide and is considered a primary respiratory parasite of cats. Definitive diagnosis is based on the identification of first-stage larvae (L1s) released in faeces approximately 5 to 6 weeks after infection. More recently, serology has been shown to be a diagnostic alternative for A. abstrusus infection in cats. The present study aimed at evaluating the diagnostic performance of serological antibody detection compared to faecal examination for A. abstrusus infection in a population of cats with known infection status from endemic areas in Italy and to identify factors (larval scores, age, co-infections with other helminths) that may influence test sensitivity and specificity of serology.

METHODS

All cats resulting positive using the Baermann technique (n = 78) were tested with the A. abstrusus ELISA. An additional 90 serum samples from cats living in three geographical areas with infection prevalence > 10%, but that resulted negative on Baermann, were also tested.

RESULTS

Among 78 cats copromicroscopically positive for L1s of A. abstrusus (Group 1), 29 (37.2%) were seropositive in ELISA. Of the 90 cats from Group 2 (cats living in three geographical areas in Italy with A. abstrusus prevalence > than 10%, but negative on Baermann examination), 11 (12.2%) were positive on ELISA. The overall seroprevalence was 23.8%. There was no statistical difference either between average optical density (OD) values of cats excreting > 100 L1s vs. cats excreting < 100 L1s (0.84 vs. 0.66; P value = 0.3247) or comparing the OD values with age of infected cats. Few Baermann-negative cats positive for Toxocara cati or hookworms were seropositive, supporting lack of cross-reactivity to these nematodes.

CONCLUSIONS

Results from the present study suggest that relying solely on faecal examination may underestimate prevalence of A. abstrusus infection in cats and that field surveys based on antibody detection are useful for establishing true prevalence of infected and/or exposed animals.

Epidemiological Survey on Gastrointestinal and Pulmonary Parasites in Cats Around Toulouse (France)

Various feline parasites are potentially zoonotic thus establishing factors associated with parasitism is of animal and public health interest. The aim of this study was to determine the prevalence of endoparasites in client-owned cats, living in the area of Toulouse, France, over the period 2015 - 2017, and to investigate possible risk factors. A total of 498 faecal samples from cats of the University Animal Hospital of Ecole Nationale Vétérinaire de Toulouse were analysed, 448 from cats presented for consultation and 50 at post-mortem. Analysis was performed using a commercial flotation enrichment method with a hypersaturated sodium chloride solution and Baermann technique. Further examination of the gastrointestinal tract contents was conducted on necropsied cats. Overall, 11.6 % of cats were positive for endoparasites; 50 (11.2 %) consultation cases and 8 (16 %) post-mortem cases, with no significant difference in prevalence between the groups. Amongst infected cats, most were infected by a single species of parasite and 10.3 % (n=6) were infected with two or more. The most common parasite was Toxocara cati with a prevalence of 9.4 % (n=47). Other endoparasites encountered were: Cystoisospora sp 1.0 % (n=5), Aelurostrongylus abstrusus 1.0 % (n=5), Strongyloides sp 0.6 % (n=3), Dipylidium caninum 0.4 % (n=2), Aonchotheca putorii 0.2 % (n=1), Ancylostomatidae 0.2 % (n=1) and Toxascaris leonina 0.2 % (n=1). The examination of the gastronintestinal tract contents of the necropsied cats revealed Mesocestoides sp 0.4 % (n=2) and Tænia (Hydatigera) tæniaeformis sensu lato 0.2 % (n=1) which are seldomly diagnosed by flotation methods. In this study, increasing age and neutered status were statistically associated with reduced odds of infection by endoparasites (helminth and coccidian). Predictors of significantly increased risk included being male, intact, and not receiving regular anthelmintic treatment. The same risk factors were highlighted specifically for Toxocara cati infections, with rural location being an additional risk factor for infection.

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.

Causes and Lesions of Fatal Pneumonia in Domestic Cats

Pneumonia in cats may cause severe lung injury and consequent death. We describe the post-mortem findings and aetiologies of naturally fatal pneumonia in 78 domestic cats, using gross and histopathological examinations, immunohistochemistry and microbiological techniques. Morphological patterns found were bronchopneumonia (27/78), interstitial (15/78), bronchointerstitial (13/78), granulomatous (8/78), aspiration (8/78) and pyogranulomatous (5/78) pneumonia, and pleuropneumonia (2/78). Bacterial pneumonia was identified as the most common cause (32/78), followed by viral (15/28 feline calicivirus, 10/28 felid alphaherpesvirus 1 and 3/28 both viruses), aspiration (8/78), fungal (5/78) and parasitic pneumonia (5/78). Co-infection with feline immunodeficiency virus and feline leukaemia virus was found in 54 cats. Viral infections involved cats of all ages, indicating the importance of investigating viral causes in cats with respiratory diseases, including in adult and ageing cats.

Causes of Death in Stray Cat Colonies of Milan: A Five-Year Report

Simple Summary

Cats have been closely linked to humans for thousands of years. Nowadays, stray cats are frequently hosted in colonies, protected, and enrolled in programs of trap–neuter-–return to control population increase. Italian public veterinary services work in collaboration with voluntary colony caretakers and are responsible for neutering and monitoring the health of colony cats. This retrospective study, conducted by the Anatomical Pathology Unit of the Teaching Veterinary Hospital of Milan in collaboration with the public veterinary services, was undertaken because of the limited information available regarding causes of death of colony cats. The study reports on and statistically analyzes the causes of death of colony cats in the city of Milan as assessed by necropsy. Inflammatory processes including those consistent with the most relevant feline infectious diseases were most common in kittens and young cats. Trauma was more frequent in adult cats, while organ failure was the most common cause of death in aged cats. Considering the possible animal welfare issues deriving from colony cats, awareness of the most common causes of death and collaboration between university veterinary pathologists and public veterinary services represent an essential contribution to health monitoring of colony cats and can assist in the rapid detection of possible emerging animal welfare concerns.

Abstract

The presence of cats in urban environments has a long history. In Italy, stray cats are protected by national and regional laws, and programs of neutering and reintroduction to colonies are ongoing. Colony cats have been widely studied from a behavioral perspective, while surveys regarding their causes of death are limited, although they may provide relevant information related to public health and cat welfare. This retrospective study provides pathological descriptions and statistical analyses of the causes of death of 186 cats from 100 colonies in the city of Milan. Inflammatory processes represent the primary cause of death (37.7%) and include common feline infectious diseases such as feline panleukopenia (67.5%), particularly in kittens, and feline infectious peritonitis (32.5%), most common in adult cats. Trauma was found to be a common cause of death of young/adult cats (14%) with a generally good body condition, while severe parasitosis was less represented (2.6%). The death of old cats was statistically associated with organ failure (24.7%), particularly renal failure, and tumors (11.8%). Knowledge of the most common causes of death of colony cats could make an important contribution to the health monitoring of these cats and sanitary control of their habitats and provide information on possible related emerging animal welfare concerns.

Aelurostrongylus abstrusus Antibody Seroprevalence Reveals That Cats Are at Risk of Infection throughout Germany

Cats infected with the metastrongylid nematode Aelurostrongylus abstrusus may show clinical signs ranging from mild to severe respiratory disease or remain unobserved, despite damages present in the lung tissue. This study aimed to determine the seroprevalence and distribution of A. abstrusus in cats by testing serum samples from all over Germany to identify potential risk areas and strengthen disease awareness accordingly. Sera of 2998 cats were screened for the presence of antibodies against A. abstrusus by ELISA, and the data were evaluated by a geographic information system to visualise the regional distribution of the analysed samples. Overall, 12.0% of the samples tested positive (361/2998 cats, 95% confidence interval: 10.9–13.3%). Seropositive cats were identified throughout the country, suggesting that all cats in Germany with outdoor access are at risk of A. abstrusus infection and that the infection is overall underdiagnosed. Increased testing for A. abstrusus infection would allow earlier detection of infected animals, hence improving the life quality and health of cats and preventing potential death under anaesthesia.

Autochthonous Angiostrongylus cantonensis, Angiostrongylus vasorum and Aelurostrongylus abstrusus infections in native terrestrial gastropods from the Macaronesian Archipelago of Spain

The presence of zoonotic relevant Angiostrongylus cantonensis infections has recently been reported in rat final hosts and gastropod intermediate hosts in Tenerife, Spain. However, data on A. cantonensis, Angiostrongylus vasorum and Aelurostrongylus abstrusus prevalences in endemic gastropods for other islands of the Macaronesian Archipelago are still missing. In order to fill this gap, we conducted an epidemiological study on terrestrial native slug (Plutonia lamarckii) and snail (Cornu aspersum, Theba pisana, Rumina decollata) species in 27 selected locations of Tenerife, Gran Canaria, El Hierro, Lanzarote, La Palma and Fuerteventura. Overall, 131 terrestrial gastropods were collected in winter/spring season 2018/2019 and examined for the presence of metastrongyloid lungworm larvae via artificial digestion. The current data revealed a total prevalence of 4.6% for A. vasorum, 3.8% for A. abstrusus and 0.8% for A. cantonensis. In Tenerife, three lungworm species were detected, thereby re-confirming A. cantonensis endemicity for this island. Prevalences of snails (C. aspersum) originating from El Hierro were 5% for A. abstrusus and 15% for A. vasorum, respectively, with larval burdens up to 290 larvae per specimen. This epidemiological study indicates the presence of human, canine and feline lungworm species in Macaronesia, Spain. The current data-particularly those on anthropozoonotic A. cantonensis-call for a regular large-scale monitoring on intermediate hosts, paratenic hosts and definitive hosts to prevent further spread of lungworm-related diseases in humans and animals.

Aelurostrongylus abstrusus Infections in Domestic Cats (Felis silvestris catus) from Antioquia, Colombia

Although Aelurostrongylus abstrusus infections in domestic cats (Felis silvestris catus) have sporadically been reported in Colombia, there is still no data available on epidemiology nor on the biology of this neglected lungworm parasite. Thus, this epidemiological study aimed to evaluate the occurrence of patent A. abstrusus infections in domestic cats from the Colombian Federal State of Antioquia. In total, 473 fecal samples of indoor/outdoor domestic cats were collected and analyzed thereafter by the Baermann funnel migration technique for the presence of A. abstrusus first stage larvae 1 (L1). The occurrence of A. abstrusus was confirmed in 0.4% (2/473) of investigated cats. Due to the presence of patent A. abstrusus infections in investigated cats, it is unfailing to include this lungworm within differential diagnoses of feline pulmonary disorders. Despite the fact that the Baermann funnel technique is currently the cheapest and the gold standard diagnostic tool for feline aelurostrongylosis, this technique is still unknown by Colombian veterinary surgeons and rarely utilized in small animal veterinary clinics. The current survey intends to generate awareness on this neglected parasitosis and to be considered as a baseline study for future surveys monitoring feline aelurostrongylosis not only in domestic/stray cats but also in endemic wild felid species of Colombia.

Fatal Pulmonary Hypertension and Right-Sided Congestive Heart Failure in a Kitten Infected with Aelurostrongylus abstrusus

Simple Summary

Infections caused by lungworms are an emerging issue in feline medicine. Clinical features in cats may vary from subclinical infections to a severe disease, occasionally including fatal pneumonia, depending on different factors, e.g., lungworm species, parasitic burden, and age of the animal. A case of infection caused by Aelurostrongylus abstrusus in a domestic kitten presenting acute dyspnoea and ascites is presented here. Clinical, radiological, echocardiographic, parasitological, molecular, and pathological data are described. This is the first report of life-threatening pulmonary hypertension inducing congestive heart failure caused by A. abstrusus infection in a domestic kitten.

Abstract

Aelurostrongylus abstrusus is considered the most important respiratory nematode of domestic cats worldwide. This parasite inhabits the alveoli, alveolar ducts, and bronchioles and causes a subacute to chronic respiratory clinical disease. Clinical signs may occur in domestic cats of any age, though they are more often described in young animals. Physical examination, echocardiography, thoracic radiography, pulmonary and cardiac pathological findings, classical, and molecular parasitological analysis of a six-month-old kitten referred at the Veterinary Teaching Hospital of the University of Pisa (Italy) led to a diagnosis of parasitic bronchopneumonia caused by A. abstrusus, which was complicated by severe pulmonary hypertension (PH) and right-sided congestive heart failure (R-CHF) that caused the death of the animal. Cases of reversible PH associated with A. abstrusus infection have been seldom reported in cats. This is the first report of fatal PH and R-CHF in a kitten with clinical aelurostrongylosis.

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.

Controlled field study evaluating the clinical efficacy of a topical formulation containing emodepside and praziquantel in the treatment of natural cat aelurostrongylosis

BACKGROUND

Aelurostrongylus abstrusus is the most important nematode affecting the respiratory tract of cats in terms of prevalence and clinical relevance. The aim of this randomised controlled field study was to confirm the efficacy of the spot-on containing emodepside/praziquantel (Profender, Bayer Animal Health) in the treatment of aelurostrongylosis.

METHODS

Seventeen cats with aelurostrongylosis and presenting with clinical and/or radiographic signs were included in the study. Eight cats received two biweekly doses of emodepside/praziquantel, while nine cats were allocated to a control group and received a rescue treatment at the end of the study. Clinical response was the primary outcome, while the secondary end point was the reduction of larval shedding in faeces.

RESULTS

Two weeks after the first application, the cats showed a significant, though partial, recovery of clinical signs with complete clinical and parasitological resolution. The resolution of inflammatory leucogram and a significant reduction of radiographic lesions were observed two weeks after the second treatment. Red blood cells and albumin values significantly increased after eight weeks from the second application, together with the complete regression of radiographic patterns.

CONCLUSION

Two applications of this spot-on solution two weeks apart assured complete cessation of larval shedding and led to a complete clinical, clinicopathological and radiographic recovery.

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.

The invasive giant African snail Lissachatina fulica as natural intermediate host of Aelurostrongylus abstrusus, Angiostrongylus vasorum, Troglostrongylus brevior, and Crenosoma vulpis in Colombia

BACKGROUND

Several metastrongyloid lungworms are unreported pathogens in Colombia. Angiostrongylus vasorum and Crenosoma vulpis target the cardiopulmonary system of domestic and wild canids. Aelurostrongylus abstrusus and Troglostrongylus brevior infect felids and considering that six wild felid species exist in Colombia, knowledge of feline lungworm infections is important for their conservation. The zoonotic metastrongyloids Angiostrongylus costaricensis and Angiostrongylus cantonensis can cause severe gastrointestinal and neurological diseases. Angiostrongylus costaricensis has been reported in Colombia, while Ang. cantonensis is present in neighbouring countries. Research on the epidemiology of metastrongyloids in Colombia and South America more broadly requires evaluating the role that gastropods play as intermediate hosts in their life cycles. This study assessed the prevalence of metastrongyloid larvae in populations of the invasive giant African snail, Lissachatina fulica, in Colombia.

METHODOLOGY/PRINCIPAL FINDINGS

A total of 609 Lissachantina fulica were collected from 6 Colombian municipalities. The snails were then cryo-euthanized, artificially digested and the sediments examined microscopically for the presence of metastrongyloid larvae. Based on morphological characteristics 53.3% (56/107) of the snails from Puerto Leguízamo (Department of Putumayo) were infected with Ael. abstrusus larvae, 8.4% (9/107) with Ang. vasorum larvae, 6.5% (7/107) with T. brevior larvae and 5.6% (6/107) with C. vulpis larvae, being the region with highest prevalences of the four species. Snails from Andes (Department of Antioquia) and Tulúa (Department of Valle del Cauca) were positive for Ang. vasorum larvae with a prevalence of 4.6 (11/238) and 6.3% (4/64), respectively. Species identifications were confirmed by PCR and sequencing.

CONCLUSIONS/SIGNIFICANCE

This epidemiological survey reports for first time the presence of Ael. abstrusus, T. brevior, C. vulpis and Ang. vasorum in L. fulica in a number of regions of Colombia.

Prevalence survey of gastrointestinal and respiratory parasites of shelter cats in northeastern Georgia, USA

The goal of this study was to assess the prevalence of gastrointestinal and respiratory parasites of shelter cats from northeast Georgia, thus promoting a more targeted approach in parasite diagnosis and treatment. Fecal samples of cats kept in a shelter located in Lavonia, northeastern Georgia, USA, were processed for the presence of parasites using double centrifugation sugar flotation (n = 103) and Baermann techniques (n = 98). Flotation revealed eggs of Toxocara cati (17.5%), Ancylostoma sp. (11.7%), Taeniidae (3.9%), Spirometra mansonoides (2.9%), Mesocestoides sp. (1%), Dipylidium caninum (1%), and Eucoleus aerophilus (1%), and oocysts of Cystoisospora felis (16.5%), and Cystoisospora rivolta (8.7%). Baermann diagnosed Aelurostrongylus abstrusus larvae in 5 cats (5.1%), while fecal flotation alone identified only 2 of these infections. Taeniidae eggs were identified to species-level by PCR and sequencing targeting the cytochrome oxidase c subunit 1 (cox1) of the mitochondrial DNA. All isolates belong to Hydatigera taeniaeformis sensu stricto, which is the first unequivocal report of the species in North America. Overall, 45.6% of the cats were infected with at least one parasite. This prevalence of infection is much higher than what is generally reported in client owned animals, highlighting the importance of using appropriate fecal diagnostic techniques to detect gastrointestinal and respiratory parasites on newly adopted cats. Correct diagnosis may direct appropriate treatment and control strategies, which would mitigate the risk of infection of other animals in household, and human exposure to zoonotic parasites.

Prevalence of feline lungworm Aelurostrongylus abstrusus in England

Infection of cats with lungworm Aelurostrongylus abstrusus has recently been documented in the UK. Here, we aimed to study the prevalence of A. abstrusus in fecal samples from cats across England. A total of 950 fecal samples were collected from cats together with information on their age, breed, gender, geographic region, lifestyle, and treatment history. A total of 17 (1.7%) cats were positive for A. abstrusus based on species-specific morphological features of the larvae isolated by Baermann's technique. There was no statistically significant difference in the proportion of positive samples between females (506; 53.2%) and males (444; 46.7%). Multiple regression analysis showed that prevalence of feline lungworm was significantly different across geographic regions: in comparison with East Midlands, some regions had shown significantly increased odds of A. abstrusus-positive samples (South East [odds ratio [OR] = 7.68; 95% confidence interval [CI] = 1.70 to 32.76; p = .01]; West Midlands [OR = 6.20; 95% CI = 1.21 to 26.84; p = .02]), while other regions had also increased odds although not statistically significant (Greater London [OR = 9.63; 95% CI = 0.43 to 84.05; p = .07]; North West [OR = 4.25; 95% CI = 0.59 to 20.89; p = .09]; South West [OR = 2.48; 95% CI = 0.12 to 17.64; p = .43]; and North East [OR = 1.88; 95% CI = 0.10 to 12.24; p = .57]). Keeping cats inside was protective against the risk of infection compared with those having outdoor access (OR = 0.09; 95% CI = 0.01 to 0.48; p = .02). On the other hand, age, breed, gender and deworming history did not have any significant effect on the likelihood of infection. Our data indicate that A. abstrusus is a parasite of potential significance in cats, in particular those from certain geographic regions in England. To reduce the spread of this parasite, an integrated feline lungworm control program needs to be implemented.

Seroprevalence, biogeographic distribution and risk factors for Aelurostrongylus abstrusus infections in Swiss cats

The metastrongyloid nematode Aelurostrongylus abstrusus is a worldwide occurring feline lungworm. The spectrum of clinical signs in infected cats ranges from mild (e.g. nasal discharge or cough) to severe respiratory distress. The aim of this seroepidemiological study was to define prevalence and risk factors for A. abstrusus infections in Swiss cats, to assess the biogeographic distribution and to investigate the influence of temperature and altitude on the occurrence of this parasite. Sera of 4067 domestic cats were collected from all over Switzerland, tested for the presence of antibodies against A. abstrusus by a novel ELISA and the results correlated with biogeographic aspects. A subsample of 1000 datasets was used for risk factor analyses. Overall, 10.7% (434/4067, 95% confidence intervals [CI]: 9.7-11.7%) of the cats were tested positive, with variations from 0.0% to 20.0% among ten different biogeographic regions. Differences were significant between the Western (13.9%, CI: 11.4-16.7%) and the Eastern (9.2%, CI: 8.0-10.5%) Swiss Plateau, possibly attributable to the suitability of the areas for intermediate hosts. In total 90.3% (392/434) of the seropositive cats originated from regions lower than 700 m above sea level. Correspondingly, 98.9% (429/434) of positive samples were obtained from regions with a mean temperature higher than -2 °C in January, suggesting altitude and temperature being limiting factors for A. abstrusus infections in Switzerland. Concerning individual risk factors, prevalence was higher in intact (15.5%, CI: 9.5-23.4%) than in neutered cats (5.8%, CI: 7.9-10.4%). Young adult cats (aged 11-22 months) were significantly more often seropositive (10/76, 13.2%, CI: 6.5-22.9%) than kittens aged 1-10 months (1/34, 2.9%, CI: 0.1-15.3%) or adult and senior cats > 22 months (58/889, 6.5%, CI: 5-8.4%). Outdoor cats and cats presenting respiratory signs tend to be more often positive than indoor cats (p =  0.077) and animals without respiratory signs (p = 0.086), respectively. We here confirm that the use of a serological test can contribute to improve the identification of infected animals, through evaluation of risk factors on a population level and for a better management on an individual level, overcoming the challenges represented by faecal examinations and the correlated underestimation of the occurrence of A. abstrusus in cats.

One-year parasitological screening of stray dogs and cats in County Dublin, Ireland

To date, there are no recent studies identifying the prevalence of parasites of human and veterinary importance in dogs and cats in Ireland. The interaction between pets and wildlife species in the environment is an important source of parasite exposure to canids and felines, and one likely to be heightened in the stray animal population. This study aimed to establish the prevalence of endoparasites in unowned dogs and cats in County Dublin, Ireland. Feces from stray dogs (n= 627) and cats (n= 289) entering a rehoming centre were collected immediately after defecation. The main parasitic agents detected were ascarids (15.52 and 30.26%),Cystoisospora(3.27 and 3.69%),Giardiaspp. (6.02 and 1.84%) and lungworms (0.64 and 2.08%), in dogs and cats respectively. Animals younger than 3 months of age were more likely to be infected with ascarids (P< 0.001) andCystoisosporaspp. (P= 0.008 andP= 0.014) than older animals. All lungworms were morphologically identified and dogs were infected withAngiostrongylus vasorum(0.48%) andCrenosoma vulpis(0.16%) whereas cats were only infected withAelurostrongylus abstrusus(2.08%). This represents the first prevalence study of stray animals in Ireland. Data collected will inform the treatment and in addition, the future monitoring and control studies of parasite populations.

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.

Angiostrongylus vasorum and Aelurostrongylus abstrusus: Neglected and underestimated parasites in South America

The gastropod-borne nematodes Angiostrongylus vasorum and Aelurostrongylus abstrusus are global causes of cardio/pulmonary diseases in dogs and cats. In the last decade, the number of reports on canine and feline lungworms has increased in several areas of Europe and North America. The unspecific clinical signs and prolonged course of these diseases often renders diagnosis challenging. Both infections are considered as emerging and underestimated causes of disease in domestic pets. In South America, little information is available on these diseases, apart from occasional reports proving the principle presence of A. vasorum and A. abstrusus. Thus, the purpose of this review is to summarize reports on infections in both domestic and wildlife animals in South America and to increase the awareness on gastropod-borne metastrongyloid parasites, which also include important zoonotic species, such as A. cantonensis and A. costaricensis. This review highlights the usefulness of diagnostic tools, such as the Baermann funnel technique, serology and PCR, and proposes to include these routinely on cases with clinical suspicion for lungworm infections. Future national epidemiological surveys are recommended to be conducted to gain a deeper insight into the actual epidemiological situation of gastropod-borne parasitoses in South America.

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.

Case report: Severe and progressive bronchopneumonia by Aelurostrongylus abstrusus in an adopted stray cat from Portugal

The cat lungworm Aelurostrongylus abstrusus is the most common respiratory parasite of cats. This nematode has a worldwide distribution and is considered an emerging pathogen. Respiratory signs overlap with those of other pathologies, and some agents which co-exist in the same animal may concur in the clinical scenario. Nonetheless, feline verminous bronchopneumonia is underestimated by practitioners and is not commonly included in differential diagnosis in routine practice. The present report describes the clinical presentation of a 6-month old stray cat from central Portugal, which developed respiratory distress. A clinical improvement of lower respiratory signs was achieved after a course of doxycycline and prednisolone course. However, a relapse with a progressive decline in the respiratory functions occurred two weeks later. A further investigation led to the identification of an A. abstrusus infection that was treated with fenbendazole. Ten days after the treatment the cat became negative for A. abstrusus and further analyses performed in the followings 2 months showed improvement of the animal's pulmonary condition and negative results at the faecal examinations. These findings indicate that veterinarians should include aelurostrongylosis in the differential diagnosis of feline respiratory distress even in non-endemic regions and should perform appropriate diagnostics procedures in the presence of compatible signs.

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.

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.

Natural infection of the feline lungworm Aelurostrongylus abstrusus in the invasive snail Achatina fulica from Argentina

The giant African snail Achatina fulica is an invasive mollusk native to Africa, the first record in Argentina was in Puerto Iguazú, in northeastern Argentina in 2010. Recently it was reported in Corrientes Province. This snail can act as an intermediate host of Metastrongyloidea nematodes of importance in public health as: Angiostrongylus cantonensis, Angiostrongylus costaricensis and Angiostrongylus vasorum. Taking into account the presence of A. fulica in Argentina, the objectives of this study is to assess the presence of Metastrongyloidea nematodes in this mollusk species in Puerto Iguazú, Misiones, close to the international border with Brazil and Paraguay. A total of 451 samples were collected from February 2014 to November 2015. The snails were processed using a digestion technique to recover the parasites. A total of 206 nematodes larvae were founded in the digestion solution of 10 hosts (P=2%; MA=0.5; MI=21). Third larval stage (L3) nematodes identified as Aelurostrongylus abstrusus were founded parasitizing the snails. No other larval stage was observed. This species has veterinary importance because it causes 'aelurostrongilosis', also known as feline strongyloidosis. This study constitutes the first record of a Metastrongyloidea nematode in A. fulica in Argentina and also highlights the susceptibility of this mollusk as intermediate host of other helminthes of health importance. The present study suggests that there is a need to establish an epidemiological monitoring system in order to prevent the possible installation of an infected mollusks focus.

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.

Relation between Aelurostrongylus abstrusus larvae excretion, respiratory and radiographic signs in naturally infected cats

A study was carried out to assess the possible relation between the number of Aelurostrongylus abstrusus larvae per gram of feces (LPG) with respiratory signs and radiographic findings in naturally infected cats. Out of 196 owned cats, 52 (26.5%) were found infected with A. abstrusus. Positive cats were divided into 4 age groups (1, 2-6 months; 2, 7-11 months; 3, 1-5 years and, 4, >6 years). Thoracic radiographs in double orthogonal views were carried out and cats were ranked on the basis of the respiratory signs (0, no symptoms; 1, mild; 2, moderate and 3, severe symptoms) and radiographic changes. Data showed that increasing LPGs were associated with higher probability to develop more severe symptoms, although some asymptomatic cats had high number of LPGs. Radiographic score and LPGs decreased with increasing cat age. A. abstrusus should be included in the differential diagnosis of lung diseases also in cats with mild respiratory symptoms.

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.

Efficacy of Emodepside/Praziquantel Spot-on (Profender®) against adult Aelurostrongylus abstrusus Nematodes in Experimentally Infected Cats

The adulticidal efficacy of a topical combination of emodepside 2.1 % (w/v) plus praziquantel 8.6 % (w/v) (Profender® spot-on for cats, Bayer) against adult Aelurostrongylus abstrusus nematodes was evaluated in two randomised, placebo-controlled laboratory efficacy studies. Each study involved 16 cats experimentally inoculated with L3 (800 and 600 each in studies no. 1 and 2, respectively) and randomised into two study groups of 8 cats each after onset of patency. While cats in the treatment group in study no. 1 received a single spot-on application at the minimum therapeutic dose (3 mg/kg emodepside and 12 mg/kg praziquantel), cats in study no. 2 were treated twice with an interval of 14 days. The faecal output of first stage larvae was monitored throughout the study. Necropsy was conducted 4 or 5 weeks after the (first) treatment and the worm counts were used for efficacy calculations. The control groups showed a geometric mean of the total worm count (live and dead worms) of 28.8 (study no. 1) and 17.6 (study no. 2), respectively. All control animals were infected. While the single treatment in study no. 1 resulted in a reduction of the total worm burden by 73.0 % (p = 0.0070), the treatment protocol in study no. 2 was 99.2 % effective (p = 0.0035). Based on live worm counts, the efficacy in study no. 2 was 100 % (p = 0.0030). It is concluded that two applications of Profender® spot-on given two weeks apart represent a safe and highly efficacious treatment regime against feline aelurostrongylosis.

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.

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.

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.

Lungworm disease in cats: ABCD guidelines on prevention and management

OVERVIEW

Cardiopulmonary nematodes are emerging parasites of cats in Europe. A number of helminth parasites may be involved. The most prevalent lungworm in domestic cats is Aelurostrongylus abstrusus. Oslerus rostratus and Troglostrongylus species are found mainly in wild cats. The trichurid Capillaria aerophila has a low host specificity and is not uncommon in cats. Additionally the lung flukes Paragonimus species are reported in many species outside of Europe, including cats.

CLINICAL SIGNS

Lungworm infections may be asymptomatic, or cause mild to severe respiratory signs, dependent on the worm species and burden; mixed infections are observed. Kittens can be vertically infected and may develop a more severe disease. Affected cats show a productive cough, mucopurulent nasal discharge, tachypnoea, dyspnoea and, in severe cases, respiratory failure and death.

MANAGEMENT

Early diagnosis and treatment greatly improves the prognosis. First-stage larvae can be easily detected in fresh faecal samples; the Baermann migration method is the enrichment technique of choice, but takes 24 h. Lungworm larvae can be found in tracheal swabs and bronchoalveolar lavage fluid, but with less sensitivity than in faeces. Molecular methods have been developed that exhibit high specificity and sensitivity, and allow diagnosis in the prepatent phase. Treatment options include fenbendazole paste, milbemycin oxime/praziquantel and various spot-on formulations. Severe cases should receive prompt medical care in an intensive care unit.

PREVENTION

Avoiding predation is at present the only preventive measure for pulmonary worms with indirect life cycles.

ZOONOTIC RISK

C aerophila has zoonotic potential, causing severe pulmonary disease in humans. Some Paragonimus species are also of zoonotic concern.

Occurrence of Aelurostrongylus abstrusus (Railliet, 1898) in Danish cats: A modified lung digestion method for isolating adult worms

As Aelurostrongylus abstrusus has not previously received any attention in Denmark, the study investigated the occurrence of A. abstrusus amongst outdoor cats from three regions (Zealand, Møn and Falster). Faeces and lungs were collected from a total of 147 feral (n=125) and domesticated cats (n=22) that were euthanized for reasons outside of this project. Using a modified Baermann technique 13.6% of the cats was found to be positive. A new lung digestion technique was developed to isolate eggs, L1 and adult worms from the lungs and this revealed a prevalence of 15.6% although with regional differences. There was no difference between feral and domesticated cats just as sex and age did not appear to influence prevalence and worm burden. Lungs from 87% of the positive cats had the gross appearance compatible with A. abstrusus and the severity of lung damage was proportional to LPG and number of adult worms. Within the current range of worm burdens (0-22) with a mean intensity of 7 per cat, there was a correlation with faecal excretion levels of L1 that ranged from 0-39,000 with a mean of 3586 per cat. The results did not indicate that the infection levels of the naturally infected cats were substantially affected by acquired immunity, but further studies are needed to determine the importance of host immune responses in regulating parasite populations.

Parasites of domestic owned cats in Europe: co-infestations and risk factors

BACKGROUND

Domestic cats can be infested by a large range of parasite species. Parasitic infestations may cause very different clinical signs. Endoparasites and ectoparasites are rarely explored in the same study and therefore multiparasitism is poorly documented. The present survey aimed to improve knowledge of the prevalence and risk factors associated with ecto- and endoparasite infestations in owned cats in Europe.

METHODS

From March 2012 to May 2013, 1519 owned cats were included in a multicenter study conducted in 9 veterinary faculties throughout Europe (Austria, Belgium, France, Hungary, Italy, Romania and Spain). For each cat, ectoparasites were checked by combing of the coat surface associated with otoscopic evaluation and microscopy on cerumen samples. Endoparasites were identified by standard coproscopical examinations performed on fresh faecal samples. Risk factors and their influence on parasitism were evaluated by univariate analysis followed by a multivariate statistical analysis (including center of examination, age, outdoor access, multipet status, and frequency of treatments as main criteria) with logistic regression models.

RESULTS

Overall, 50.7% of cats resulted positive for at least one internal or one external parasite species. Ectoparasites were found in 29.6% of cats (CI95 27.3-32.0%). Otodectes cynotis was the most frequently identified species (17.4%), followed by fleas (15.5%). Endoparasites were identified in 35.1% of the cats (CI95 32.7-35.7%), including gastro-intestinal helminths in 25.7% (CI95 23.5-28.0), respiratory nematodes in 5.5% (CI95 4.2-7.0%) and protozoans in 13.5% (CI95 11.8-15.3%). Toxocara cati was the most commonly diagnosed endoparasite (19.7%, CI95 17.8-21.8%). Co-infestation with endoparasites and ectoparasites was found in 14.0% of the cats, and 11.9% harbored both ectoparasites and gastro-intestinal helminths.Age, outdoor access, living with other pets, and anthelmintic or insecticide treatments were significantly associated with the prevalence of various parasites.

CONCLUSIONS

This survey demonstrates that parasitism is not a rare event in European owned cat populations. The prevalence of multi-parasitism is significantly greater than expected by chance and hence there is tendency for some individual cats to be more prone to infestation by both endo- and ectoparasites due to common risk factors.

Efficacy of a novel topical combination of fipronil, (S)-methoprene, eprinomectin and praziquantel against larval and adult stages of the cat lungworm, Aelurostrongylus abstrusus

The efficacy of a novel topical combination of fipronil 8.3% w/v, (S)-methoprene 10% w/v, eprinomectin 0.4% w/v, and praziquantel 8.3% w/v (BROADLINE(®),(1) Merial) against larval and adult Aelurostrongylus abstrusus lungworms in cats was assessed in a controlled laboratory study. The study included 48 purpose-bred, short-haired cats which were each inoculated with 225 infective A. abstrusus larvae. The cats were formed into eight blocks based on pre-treatment bodyweight and were then, within each block, randomly allocated to one of six treatment groups: untreated control; treated once when A. abstrusus were expected to be third-stage larvae (4 days post inoculation [dpi]), fourth-stage larvae (7 dpi), immature adults (14 dpi) or adult nematodes (32 dpi), or treated twice, once when A. abstrusus were expected to be third-stage larval and once again when A. abstrusus were expected to be adult nematodes (4 dpi+32 dpi). Cats weighing ≥ 0.8-2.5 kg received one 0.3 mL applicator and cats weighing >2.5-7.5 kg received one 0.9 mL applicator. For determination of the efficacy of treatments, lungworm larval counts were established on faecal samples collected from all cats 32, 39, 46, 53 and 60 dpi. At each occasion from 46 dpi on, cats treated with fipronil, (S)-methoprene, eprinomectin and praziquantel had significantly lower A. abstrusus larval counts than the untreated controls with percentage reductions of 91.6% (cats treated 14dpi; P=0.012), ≥ 98.9% (cats treated either 4 dpi, 7 dpi or 32 dpi; P<0.001) or >99.9% (cats treated 4 dpi+32 dpi; P<0.001) at 60 dpi. Thus, the novel topical combination of fipronil, (S)-methoprene, eprinomectin and praziquantel was highly effective in the prevention and treatment of A. abstrusus lungworm infection in cats.

New insights on metastrongyloid lungworms infecting cats of Sardinia, Italy

In addition to the well-known Aelurostrongylus abstrusus (Strongylida: Angiostrongylidae), Troglostrongylus brevior (Strongylida: Crenosomatidae) has recently been diagnosed as a causative agent of bronco-pulmonary infections of cats in Spain and Italy. However, information concerning the impact of this species of lungworm on feline population is limited to a few case reports. From July 2011 to May 2013 an epidemiological survey was carried out on Sardinia island (Italy), where 107 individual faecal samples were examined by Baermann technique, and first-stage larvae were identified based on their morphology and characterization of molecular markers. The 29.9% (32/107) of cats examined were infested by broncho-pulmonary nematodes and, although A. abstrusus was the most frequently detected (n=27; 25.2%), larvae of T. brevior were also found (n=7; 6.5%). In addition, two cats (1.9%) were co-infested by both species. Overall metastrongyloid infection was higher in female cats (n=22; 38.6%) than in males (n=10; 20%) (χ(2)=4.39; p=0.036). The mean age of positive animals was 21.1 (±29.8) months, being infected animals from 2 months to 10 years of age. Of the 32 animals that scored positive for lungworms only 6 (18.8%) displayed a respiratory condition associated with lungworm infestations. Biomolecular characterization confirmed the morphological diagnosis of A. abstrusus. Positive samples that were identified at genus level as Troglostrongylus spp. were molecularly characterized as T. brevior. This study represents the first epidemiological survey on metastrongyloid lungworms of domestic cats in Sardinia and the first report of T. brevior on this island.

Clinical, laboratory and pathological findings in cats experimentally infected with Aelurostrongylus abstrusus

Aelurostrongylus abstrusus parasitizes the respiratory tract and can heavily affect the breathing and general condition of cats. Experimental infections of six cats were initiated by intragastric administration with 100 or 800 third-stage larvae (L3) obtained from the terrestrial snail Helix aspersa. First-stage larvae were isolated from faecal samples after 35-41 days post infection (dpi) in five animals and until end of study (84 dpi) in two cats. Cough and respiratory sounds were observed starting from 28 to 41 dpi and dyspnoea and panting starting from 52 dpi. All cats had enlarged lymph nodes and, starting from 56 dpi, reduced body weight, and four cats showed intermittent reduced general condition with apathia and anorexia. Eosinophilia and leucocytosis partially with massive lymphocytosis, and occasional basophilia and monocytosis were observed. Mild anaemia was present in five cats, while alterations in coagulation parameters suggested stimulation of the coagulation cascade with increased consumption of coagulation factors (delayed PT, hypofibrinogenemia). Adult A. abstrusus specimens were isolated from the five patent cats at necropsy and all six cats showed pathological changes in the lungs, including disseminated inflammatory cell infiltrates, often associated with incorporated larvae and eggs. There was some degree of overlap between the severity and the inoculation doses. Infections starting from 100 L3 of A. abstrusus had an impact on the lung tissues and on the health of the cats, despite the presence of only mild haematological abnormalities. Due to the worldwide occurrence of feline lung worms, parasitic infections should be considered in the differential diagnosis of lung diseases regardless of the presence of clinical signs and larval excretion.

Lungworms of the genus Troglostrongylus (Strongylida: Crenosomatidae): neglected parasites for domestic cats

Feline lungworms belonging to the Troglostrongylus genus have been neglected for a long time. However, recent reports of Troglostrongylus brevior and Troglostrongylus subcrenatus in domestic cats have stimulated the interest of the scientific community on these lungworms. Troglostrongylus spp. have an indirect life cycle, which overlaps that of the better known Aelurostrongylus abstrusus. Nonetheless, adult worms of both genera have a distinct morphology and localization within the respiratory system of definitive hosts and, potentially, a different epidemiology and pathogenicity. As copromicroscopy has a low specificity for metastrongyloids due to the similarities of first-stage larvae, specific morphometrical keys and/or PCR diagnostic tools are advocated. Accordingly, more clinical studies and necropsy data are needed to elucidate the impact of Troglostrongylus spp. on the health of domestic cats. This article reviews current information on Troglostrongylus spp. as well as data on their occurrence in Europe and reports specific key morphological characters for the identification of adults and larvae, which is important to refine their diagnosis and for a better understanding of the feline lungworm infections.

Mixed infection by Aelurostrongylus abstrusus and Troglostrongylus brevior in kittens from the same litter in Italy

Parasitic nematodes affecting the respiratory system of felids are spreading in endemic regions and emerging in previously free areas and/or hosts. This is particularly the case of the cat lungworm Aelurostrongylus abstrusus, which can cause respiratory signs in cats all over the world. Additionally, Troglostrongylus brevior has been recently found in domestic cats from Ibiza Island in Spain and Southern Italy. The present paper describes the first mixed infection by these lungworms in kittens belonging to the same litter. Two ∼10-11 weeks old kittens were found infected by A. abstrusus and T. brevior at a copromicroscopical examination. The identity of larvae shed by faeces were confirmed with an already validated PCR specific for A. abstrusus and a novel DNA-based assay specific for T. brevior. One kitten showed severe respiratory signs and died despite an anthelmintic treatment, while the other had a subclinical infection and recovered after a parasiticide administration with milbemycin oxime. New insights into epidemiology, biology, clinical aspects and control of these parasitoses are discussed.

Feline lungworms: what a dilemma

Aelurostrongylus abstrusus is regarded as the major lungworm infecting Felis catus, although other, albeit poorly studied, nematodes have been described from the respiratory system of domestic cats. Recent records of these neglected parasites have renewed the attention of the scientific community, but their actual role in respiratory disease in cats is blurred. The epidemiology, pathogenic role, and diagnosis of Troglostrongylus spp., Oslerus rostratus, and Capillaria aerophila in domestic cats are far from being clarified. Indeed, recent studies have provided novel information but have also given rise to relevant doubts. We discuss here the state of current knowledge regarding felid lungworms together with the dilemmas recently roused in the scientific literature.

Prevalence of faecal-borne parasites in colony stray cats in northern Italy

Endoparasitic infections are common in stray cats. Many of these parasites are responsible for zoonoses, and stray cats can be a source of environmental contamination. The prevalence of parasites in 139 stray colony cats in the city of Milan, northern Italy, was investigated by faecal examination. The overall prevalence of endoparasites was 50.4%, with 11 different parasites found. Parasites with zoonotic potential were detected in 49.6% of cats. Concurrent infections with two or more zoonotic parasites were recorded in 14.3% of cats. Among the parasites found, the most common was Toxocara cati (33.1%; P <0.0001). The other species found by coproscopic examination were: Ancylostoma tubaeformae (7.2%), Isospora species (4.3%), Trichuris vulpis (2.9%), Dipylidium caninum (2.9%), Aelurostrongylus abstrusus (2.9%), Eucoleus aerophilus (syn Capillaria aerophila) (1.4%), Spirometra species (1.4%), Taenia pisiformis (0.7%) and Hymenolepis nana (0.7%). Coproantigen specific for Giardia duodenalis was detected in 2.9% of the samples. Pseudoparasites (eggs of mites) were found in 4.3% of the samples. No sample contained Toxoplasma gondii oocysts, despite the fact that 70 cats tested positive for T gondii-specific IgG antibodies, and none of the diarrhoetic samples tested positive for Cryptosporidium species oocysts. Variables linked to infection were body condition score (BCS), the presence of diarrhoea and infection with G duodenalis. Cats infected with G duodenalis were more likely to have a low BCS (odds ratio (OR) = 11.5, P = 0.02) and diarrhoea (OR = 30.7, P = 0.0007). The results of the present study confirm that endoparasitic infections, most of which have zoonotic potential, are distributed in stray colony cats of Milan.

Larval development of the feline lungworm Aelurostrongylus abstrusus in Helix aspersa

The cat lungworm Aelurostrongylus abstrusus affects the domestic cat and other felids all over the world. Feline aelurostrongylosis is of importance in clinical feline medicine and is gaining more and more attention for the present expansion in the geographical range of A. abstrusus. Global warming and changes in phenology of snail intermediate hosts have been incriminated in this spreading. Helix aspersa, a potential vector of A. abstrusus, is endemic in most regions of the world, where it has become recently a pest outside its native Mediterranean range. The present work evaluated key features of larval development of A. abstrusus in H. aspersa at two different temperature conditions. The results showed that A. abstrusus may reach the infective stage in muscular foot and viscera of H. aspersa and that environmental temperatures may influence the biological cycle of the cat lungworm. In particular, the higher the average temperature, the higher the rate of larval development, i.e., about 50% of larvae of A. abstrusus reached the infective stage between temperatures of 18.8-29.5 °C, while only 17.8% of larvae completed their development at temperatures of 6.7-22 °C. Biological and epidemiological implications are discussed.

Evaluation of the efficacy of selamectin spot-on in cats infested with Aelurostrongylus abstrusus (Strongylida, Filariodidae) in a Central Italy cat shelter

In recent years Aelurostrongylus abstrusus has often been reported in Italy. This lungworm is very common in cat colonies due to its route of transmission. Deciding a therapeutic approach can be difficult in such colonies, because there is no certainty whether oral medicines administered with food, or with what dose, will be taken. In this field study, stool samples were taken from 42 cats and analysed for A. abstrusus L1 larvae with Baermann technique. Ten cats testing positive were treated with a spot-on formulation of selamectin 45 mg. Clinical examinations and laboratory tests, repeated four times in two months, demonstrated the success of the treatment in 9 of the 10 cats. Improvements in respiratory signs and general clinical condition were reported after treatment.