Aelurostrongylus abstrusus in a feline colony from central Italy: clinical features, diagnostic procedures and molecular characterization

A Comparison of Copromicroscopic and Molecular Methods for the Diagnosis of Cat Aelurostrongylosis

Simple Summary

Feline aelurostrongylosis is a worldwide distributed parasitic disease of domestic cats caused by the nematode Aelurostrongylus abstrusus. Cats may have a subclinical infection with this parasite or may show signs that overlap with those of many other respiratory conditions of cats, either parasitic or not. The diagnosis of feline aelurostrongylosis currently relies on fecal examinations, though this approach has some limits that can be overcome by innovative molecular techniques. Therefore, the present study has investigated the diagnostic reliability of a PCR assay performed on different samples collected from cats from Italy and Greece. The results of the study confirmed that PCR is highly sensitive and specific for the diagnosis of A. abstrusus infections in domestic cats.

Abstract

The gold standard method for the diagnosis of cat aelurostrongylosis is the detection of Aelurostrongylus abstrusus first stage larvae with the Baermann’s examination. Nevertheless, molecular assays have shown higher diagnostic performances compared to copromicroscopy. This study evaluated the usefulness of an A. abstrusus species-specific PCR on different biological samples collected in clinical settings from 100 privately-owned cats in Italy (n. 60) and Greece (n. 40). A fecal sample was collected from each animal and a pharyngeal swab was also obtained for cats from Italy. All stool samples were subjected to flotation and Baermann’s test. The cats were categorized in three groups based on the results of copromicroscopy, i.e., Group A (n. 50 cats with A. abstrusus infection regardless of positivity for other helminths), Group B (n. 25 cats negative for A. abstrusus but positive for at least one of any other helminth), Group C (n. 25 cats negative for any helminth). DNA was extracted from individual aliquots of feces, flotation supernatant, Baermann’s sediment and the pharyngeal swab and then subjected to a PCR specific for A. abstrusus. At least one fecal aliquot or the pharyngeal swab scored positive by the A. abstrusus-specific PCR for 48/50 (96%) cats enrolled in Group A; in particular, 38/50 (76%), 35/50 (70%), 41/50 (82%) and 21/25 (84%) DNA extracts from feces, flotation supernatant, Baermann’s sediment and pharyngeal swabs were positive by PCR. These results confirm that molecular tools are highly sensitive and specific and indicate that pharyngeal swabs are the most suitable sample for molecular analysis in clinical settings.

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.

Do All Roads Lead to Rome? The Potential of Different Approaches to Diagnose Aelurostrongylus abstrusus Infection in Cats

An infection with the cat lungworm, Aelurostrongylus abstrusus, can be subclinical, but it can also cause severe respiratory clinical signs. Larvae excretion, antibody levels, clinical assessment findings of the respiratory system and diagnostic imaging findings were recorded and compared for six cats with experimental aelurostrongylosis. In five cats, patency started 33-47 days post infection (pi), but two cats excreted larvae only in long intervals and low numbers. Positive ELISA results were observed in four cats with patent aelurostrongylosis, starting between five days before and 85 days after onset of patency. One seropositive cat remained copromicroscopically negative. Mild respiratory signs were observed in all cats examined. A computed tomographic (CT) examination of the lungs displayed distinct alterations, even in absence of evident clinical signs or when larvae excretion was low or negative. The thoracic radiograph evaluation correlated with the CT results, but CT was more distinctive. After anthelmintic treatment in the 25th week post infection, pulmonary imaging findings improved back to normal within 6-24 weeks. This study shows that a multifaceted approach, including diagnostic imaging, can provide a clearer diagnosis and monitoring of disease progression. Furthermore, a CT examination provides an alternative to post mortem examination and worm counts in anthelmintic efficacy studies.

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.

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.

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.

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.

Seroprevalence of antibodies against the cat lungworm Aelurostrongylus abstrusus in cats from endemic areas of Italy

Aelurostrongylus abstrusus (Nematoda, Metastrongyloidea) is a worldwide occurring lungworm causing verminous pneumonia in cats. To date the Baermann method is the most used procedure to diagnose A. abstrusus infection by isolating first stage larvae from faeces, though its sensitivity and specificity can be impaired by several factors. An enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against A. abstrusus has been recently developed as a diagnostic alternative. The present study evaluated the seroprevalence for A. abstrusus infection in cats from two endemic areas of Italy. Overall, 250 sera were sampled and tested for the presence of antibodies against A. abstrusus. Based on the results obtained from 20 cats proven to be infected by A. abstrusus using Baermann technique and molecular methods, and from 20 negative cats (Subset A), a cut off value of 0.347 optical density (OD) was determined, leading to a sensitivity of 95% and a specificity of 100%. Two-hundred and ten cats (142 and 68 from Abruzzo and Umbria regions, respectively) were included in Subset B (i.e. 202 negative by Baermann examination and 8 positive for Troglostrongylus brevior). Antibodies against A. abstrusus were detected in forty-five (21.4%, 95% CI: 16.1-27.6%) samples. This study confirms the occurrence of A. abstrusus in endemic areas of Italy and indicates that one-fifth of randomly selected cats have or had a lungworm infection with production of antibodies.

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.

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.

Larval development of Aelurostrongylus abstrusus in experimentally infected Rumina decollata snails

Aelurostrongylus abstrusus is a lungworm distributed worldwide that affects wild and domestic cats, causing bronchopneumonia of varying intensity. Snails serve as intermediate hosts. The aim of the present study was to assess the larval development of A. abstrusus in R. decollata snails and to investigate its potential as an intermediate host. For this purpose, first-stage larvae (L1) of A. abstrusus were obtained from the faeces of naturally infected cats. Doses of 500 L1/snail were given to 24 R. decollata snails, placed on the soil of the breeder chamber, and maintained under laboratory conditions. Three snails were killed at 8, 10, 12, 16, 22, 26, 45 and 55 days post-infection (dpi), and the muscular foot and visceral body were separately digested by an artificial digestion technique. The morphometric parameters of different larval stages were recorded. The mean number of larvae reaching the infective stage at the end of the study (L3) was 262 larvae/snail. The greatest development to L3 was recorded from days16 to 55 pi, during which the isolation was maximum. A. Abstrusus L3 were isolated from the viscera, but isolation from the snail foot was significantly higher. Our results showed for the first time the ability of A. Abstrusus larvae to develop in R. decollata, thus serving as a potential intermediate host.

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.

Fatal aelurostrongylosis in a kitten in Serbia

This paper describes a case of aelurostrongylosis in a four-month old female domestic cat (Felis catus) from South Banat, Serbia. The kitten that had died suddenly without signs of illness was autopsied in the Veterinary Specialised Institute "Pančevo". The macroscopic finding was typical of granulomatous pneumonia and subsequently, histopathology revealed verminous pneumonia. Based on the parasite morphology, it was confirmed that the lung lesions were caused by Aelurostrongylus abstrusus. The present finding contributes to the knowledge of the prevalence of this underestimated parasite in the Balkan Peninsula.

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.

Epidemiological survey of zoonotic helminths in feral cats in Gran Canaria island (Macaronesian archipelago-Spain)

The presence of zoonotic parasites in feral cats have been widely considered all over the world. In Gran Canaria (Macaronesian archipelago, Canary Islands, Spain) the number of feral cats has grown out of control in urban and rural areas. 48 of Felis catus captured in different Gran Canaria areas were studied. Animals were necropsied and several organs were systematically examined in order to collect and identify macroscopic parasites. In addition, coprological tests were done in 28 cats. There were no statistically significant differences in the prevalence rate among sex, age or capture area, showing an overall prevalence of helminths of 77.1%. The most common tapeworms were Dipylidium caninum (64.6%) and Taenia taeniaeformis (31.3%), followed by the nematodes Toxocara cati (20.8%), Ancylostoma tubaeforme (18.8%), Aelurostrongylusabstrusus (10.4%) and Trichuris vulpis (2.08%). We also find several eggs of Alaria alata in the small intestine of one cat (2.08%), being the first description of this trematode in cats in the Canary Islands. Aproximatelly, 40% of the studied cats harboured more than one parasite. High rates of zoonotic species found in these animals suggest the need of controling parasitic infections and preventive measures against them.

Multiparasitism in a wild cat (Leopardus colocolo) (Carnivora: Felidae) in southern Brazil

Abstract Parasitic diseases reflect the health and balance of ecosystems, affecting not only individuals but also entire populations or communities. The aim of this study was to report on the diversity of parasitic helminths detected in the feces of a wild feline in southern Brazil. Parasites were obtained from fecal samples, and four techniques were used for parasitological examination: direct examination, centrifugal flotation with zinc sulfate (Faust technique), simple sedimentation (Hoffman technique) and Baermann-Moraes. The parasites were identified through micrometry and morphology, as follows: Ancylostoma sp., Toxocara sp., Trichuridae, Aelurostrongylus abstrusus, Alaria sp., and Spirometra sp. We recorded the genus Ancylostoma parasitizing L. colocolo for the first time.

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.

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.

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.

Detection of feline Mycoplasma species in cats with feline asthma and chronic bronchitis

Little is known about the aetiology of inflammatory lower airway disease in cats. The aim of this study was to investigate the role of Mycoplasma species in cats with feline asthma (FA) and chronic bronchitis (CB). The study population consisted of 17 cats with FA/CB, and 14 sick cats without clinical and historical signs of respiratory disease, which were euthanased for various other reasons. Nasal swabs, nasal lavage and bronchoalveolar lavage fluid (BALF) samples were taken from patients from both groups. Mycoplasma species culture with modified Hayflick agar and Mycoplasma polymerase chain reaction (PCR) were performed on all samples followed by sequencing of all Mycoplasma species-positive samples for differentiation of subspecies. PCR testing detected significantly more Mycoplasma species-positive BALF samples than Mycoplasma culture (P = 0.021). When cats with oropharyngeal contamination were excluded from comparison, the numbers of Mycoplasma species-positive BALF samples in the group with FA/CB (6/17) and the control group (4/9) were not significantly different (P = 0.6924). While all nasal samples of the cats with FA/CB were negative for Mycoplasma organisms, five samples in the control group (P = 0.041) were positive on PCR. Sequencing revealed Mycoplasma felis in all PCR-positive samples. Mycoplasma species can be detected in the lower airways of cats with FA/CB, as well as in the BALF of sick cats without respiratory signs. Further studies are warranted to investigate the possibility that Mycoplasma species represent commensals of the lower respiratory tract of cats.

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

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

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.

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

Aelurostrongylus abstrusus affects the respiratory system of domestic cats worldwide, causing different clinical signs. Recently, Troglostrongylus brevior, a parasite found only in feral and wild animals until 2010, has been regarded as a cause of potentially severe bronchopneumonia in domestic cats. The life cycle of both nematodes involves the same intermediate (i.e. land mollusks) and paratenic hosts (i.e. lizards, birds and small mammals). Biological and epidemiological drivers may cause the spreading of A. abstrusus along with a possible emergence of T. brevior from marginal areas and limited hosts. Given the merit in increasing knowledge on these potentially emerging nematodes, the present paper describes clinical features and the first post mortem gross and histopathological observations in a case of mixed infection by A. abstrusus and T. brevior in a kitten.

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.

Simultaneous detection of the feline lungworms Troglostrongylus brevior and Aelurostrongylus abstrusus by a newly developed duplex-PCR

In addition to Aelurostrongylus abstrusus (Strongylida: Angiostrongylidae), referred to as the feline lungworm, Troglostrongylus brevior (Strongylida: Crenosomatidae) has recently been identified as an agent of bronco-pulmonary infestations in cats. These two parasites have a similar biology, share ecological niches, potentially co-infesting cats, but are difficult to be differentiated due to the morphological similarities of their first-stage larvae (L1). This paper describes a molecular tool, based on single-step duplex polymerase chain reaction (duplex-PCR) on the ribosomal internal transcribed spacer 2 region (ITS-2) for the simultaneous detection and differentiation of T. brevior and A. abstrusus. L1 of both species were collected from faecal samples, morphologically identified, and single larval specimens isolated. An aliquot of faeces was used as a test sample for a case of mixed natural infestation. The duplex-PCR was performed using species-specific forward primer sets for the ITS-2 region (i.e., A. abstrusus: 220bp; T. brevior: 370bp). The detection limit of the molecular assay was also assessed by serial dilutions of DNA from single larvae of both species (from ≈ 4.0 to 4.0 × 10(-5) μg/μl). The duplex-PCR carried out on individual DNA samples was able to detect as low as 5.2 × 10(-3) μg/μl of DNA for A. abstrusus, 4.9 × 10(-3)μg/μl for T. brevior, and as low as 4.0 × 10(-3) μg/μl for samples containing both species. Species-specific bands of the expected sizes and two bands were simultaneously amplified from the faecal sample containing both species. The phylogenetic analyses of the ITS-2 sequences here examined and those available for other metastrongyloids were concordant in clustering them with those of other Troglostrongylus brevior and A. abstrusus sequences available in GenBank database. This molecular approach proved to be effective and highly sensitive for the simultaneous detection of the two lungworms species and it might be used for molecular epidemiological studies and for monitoring therapeutic protocols.

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 use of pooled fecal samples for the diagnosis of protostrongylid infections in sheep

The Baermann-Wetzel method is the recommended test for the diagnosis of lungworm infections. The objective of this study was to evaluate the use of pooled fecal samples for the diagnosis of protostrongylid infections in sheep flocks and to investigate the sensitivity of the pooled Baermann-Wetzel technique in relation to individual analysis, which is time consuming and expensive. Fecal samples were taken from 10 sheep flocks positive for protostrongylids located in northwestern Spain. Ten pools composed of 6 individual fecal samples, chosen at random from the entire flock sampling, were performed for each flock at the same time as individual analyses. Protostrongylid larvae were detected in 56 pools, with a 56% flock sensitivity. Flock sensitivity was positively associated with the within-flock prevalence (P<0.001), but not with the mean larvae output. A high sensitivity (78.3%) has been observed in flocks with medium or high prevalence, so pooled fecal samples can be used in those flocks that require an effective treatment regimen against these nematodes.

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.

Evidence for direct transmission of the cat lungworm Troglostrongylus brevior (Strongylida: Crenosomatidae)

Metastrongyloids of cats are emerging pathogens that may cause fatal broncho-pulmonary disease. Infestation of definitive hosts occurs after ingestion of intermediate or paratenic hosts. Among metastrongyloids of cats, Troglostrongylus brevior and Troglostrongylus subcrenatus (Strongylida: Crenosomatidae) have recently been described as agents of severe broncho-pulmonary disease. Here, we provide, for the first time, observational evidence suggesting the direct transmission of T. brevior from queen cat to suckling kittens. This new knowledge will have a significant impact on current scientific information of this parasite and shed new light into the biology and epidemiology of metastrongyloid nematodes.

Parasitic infections of domestic cats, Felis catus, in western Hungary

During 2011, faeces from 235 owned domestic cats from a rural area in western Hungary were examined using standard coproscopical techniques. The overall prevalence of cats with endoparasites was 39.6% (95% CI 33.3-46.1). The most frequently identified faecal forms were those of ascarids (Toxocara, 17.4%; Toxascaris 7.2%), followed by those of Aelurostrongylus lungworms (14.5%), hookworms (11.1%), taeniid cestodes (4.7%), Cystoisospora coccidians (4.3%), and capillarids (3.8%). Single and multiple infections with up to five parasites concurrently were founded in 24.7% and 14.9% of the cats, respectively. Mixed endoparasite infections were recorded more frequently (p=0.0245) in cats greater than one year old compared to younger cats. Young cats (≤ 1 year) were parasitized more frequently (p<0.05) with ascarids and Cystoisospora spp. but demonstrated infections of hookworms, lungworms and taeniid cestodes less often than the older cats. Cats with taeniid infection were more likely (p<0.05) to harbour Toxocara, hookworm, Aelurostrongylus, and capillarid infections than cats without taeniid cestodes. Cats of owners who claimed the use of wormers were less frequently helminth-positive compared to cats whose owners did not use anthelmintics (21.2% vs. 44.4%; p=0.001). A subset of 115 faecal samples screened by a coproantigen ELISA revealed Giardia-specific antigen in 37.4% samples. Giardia cysts were found by immunofluorescent staining in 30 of the 43 samples tested positive for Giardia by ELISA. In addition, ectoparasites collected from 82 cats by body search and combing were identified. Fleas (1-30 per cat), biting lice (Felicola subrostratus), and ticks (1-5 per cat) were isolated from 58, 1 and 43 cats, respectively. Ctenocephalides felis was identified on all flea infested cats while single specimens of C. canis and Pulex irritans were recovered from three and two cats, respectively. All but one tick collected were adult Ixodes ricinus; the single other tick was a nymph of I. canisuga. By providing basic data on the epidemiology of parasitic infections, the results of this survey should emphasize the need of attending to parasites of cats from the veterinary point of view with respect to both appropriate diagnostics and control.

Troglostrongylus brevior and Troglostrongylus subcrenatus (Strongylida: Crenosomatidae) as agents of broncho-pulmonary infestation in domestic cats

BACKGROUND

Aelurostrongylus abstrusus is currently regarded as the main metastrongyloid infesting domestic cats, whereas the reports of Troglostrongylus spp. in domestic and wild felids largely remain anecdotic. This paper reports on pulmonary infestation caused by Troglostrongylus brevior and Troglostrongylus subcrenatus in two kittens and describes, for the first time, associated clinical presentations and pathological features. Morphometrical, molecular and phylogenetic analyses have also been conducted to differentiate here the examined Troglostrongylus species from A. abstrusus, towards a clearer delineation of metastrongyloids affecting cats.

METHODS

Two kittens were referred for respiratory distress and hospitalized with a diagnosis of severe aelurostrongylosis, based on the presence of metastrongyloid larvae in the faeces. Despite prompt treatment, kittens died within 48 hours. Both kittens were submitted to necropsy to determine the cause of death.

RESULTS

At necropsy, nematode specimens were found in the trachea, bronchi and bronchioles and were associated with respiratory signs (i.e., dyspnoea, polypnea, severe coughing and nasal discharge). Morphology and measurements of adult parasites found allowed the unequivocal identification of T. brevior and T. subcrenatus, even if first stage larvae were rather similar to those of A. abstrusus. Briefly, T. brevior and T. subcrenatus larvae were shorter in length and lacking the typical knob-like terminal end of A. abstrusus. Molecular and phylogenetic analyses corroborated morphological identification and provided data on mitochondrial and ribosomal DNA genes of T. brevior.

CONCLUSIONS

Data presented here indicate that T. brevior and T. subcrenatus may cause major respiratory distress in domestic cats. Consequently, these two species should be included, along with A. abstrusus, in the differential diagnosis of cat bronchopulmonary affections and treatment protocols need to be evaluated. Through research on the biology, epidemiology and control of Troglostrongylus spp. infestations in domestic cats are advisable to implement current knowledge on these neglected metastrongyloids.

Improved detection of canine Angiostrongylus vasorum infection using real-time PCR and indirect ELISA

This study reports the development of a real-time PCR assay and an indirect ELISA to improve on current detection of canine Angiostrongylus vasorum infection. A highly specific fluorescent probe-based, real-time PCR assay was developed to target the A. vasorum second internal transcribed spacer region and detected DNA in EDTA blood, lung tissue, broncho-alveolar larvage fluid, endotracheal mucus, pharyngeal swabs and faecal samples. PCR was fast (∼1 h), highly efficient when using EDTA blood samples, consistently detected a single molecule of parasite DNA and did not amplify DNA from other parasitic nematodes or definitive host species. An indirect ELISA was also developed using the soluble protein fraction from adult A. vasorum worms. Some cross-reactive antigen recognition was observed when tested against sera from dogs infected with Crenosoma vulpis (n = 8), Toxocara canis (n = 5) and Dirofilaria immitis (n = 5). This was largely overcome by setting the cut-off for a positive result at an appropriately high level. Field evaluation of the real-time PCR and ELISA was conducted by testing sera and EDTA blood from dogs with suspected A. vasorum infection (n = 148) and compared with the Baermann's larval migration test in faeces. Thirty-one dogs were positive by at least one test. Of these, 20 (65%) were detected by the Baermann method, 18 (58%) by blood PCR, 24 (77%) by ELISA and 28 (90%) by blood PCR and ELISA together. Combined testing using real-time PCR and ELISA therefore improved the detection rate of A. vasorum infection and holds promise for improved clinical diagnosis and epidemiological investigation.

Lower respiratory tract infections in cats: reaching beyond empirical therapy

PRACTICAL RELEVANCE

Lower respiratory tract infections (LRTIs) in cats can be due to bacteria, parasites, fungi and viruses. This review details the practical investigation of these infections and highlights specific therapy where possible. The aim is to avoid the all-too-frequent temptation in practice to treat cats with lower respiratory tract signs empirically for feline bronchial disease (FBD)/asthma. This is potentially hazardous as immunosuppressive therapy for FBD/asthma could exacerbate disease due to a LRTI. Empirical treatment of suspected LRTI is also difficult to recommend given the wide range of potential pathogens.

CLINICAL CHALLENGES

Making a clinical ante-mortem diagnosis of LRTI in a cat can be challenging. Consistent historical, clinical, haematological and radiographic abnormalities are often lacking and findings may be non-specific. Astute clinical acumen, thorough investigation and high quality laboratory analysis are usually required for a diagnosis. Bronchoalveolar lavage, if feasible, and tests for lungworm should be routine in cats with lower respiratory tract signs. Lung fine needle aspiration may be useful in cases of diffuse or nodular pulmonary disease. Histopathology is rarely employed in ante-mortem investigations.

EVIDENCE BASE

The authors have reviewed a substantial body of literature to provide information on many of the reported bacterial, parasitic, fungal and viral pathogens, including some that occur in Asia. Attention has been given to specific therapy for each pathogen, with evidence-based comments when there is a deviation from routine recommendations.