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

A Retrospective Study of Sildenafil Administration in 55 Cats with Cardiopulmonary Disease (2009-2021)

Sildenafil is a drug used to successfully manage a variety of cardiopulmonary disorders in people and dogs, but there is limited information on its use in cats. The objective was to review the medical records of cats that received sildenafil as part of their clinical management. Medical records and pharmacy databases were searched for cats that received sildenafil for ≥24 h between 2009 and 2021, and data were collected from medical records. Fifty-five cats received sildenafil for ≥24 h and were included in the study: 43 with primary cardiac disease (acquired, n = 28; congenital, n = 15) and 12 with primary respiratory disease. Side effects possibly attributed to sildenafil were identified in two cats (systemic hypotension, n = 1; polydipsia, n = 1), and sildenafil was discontinued in the cat with hypotension. Sildenafil was discontinued in an additional three cats due to a lack of improvement in clinical signs. No cat was documented to develop worsening pulmonary edema within 72 h of starting sildenafil. Median duration of sildenafil administration was 87 days (range, 2-2362 days). Sildenafil administration in cats appeared to be generally well-tolerated. Studies are needed to determine whether sildenafil administration to cats with cardiopulmonary disease improves the quality of life or survival times.

Survey of Gastrointestinal Parasites and Lungworms in Cats and Dogs from Terceira and São Miguel Islands, Azores

Parasitic diseases can affect animal health and welfare, and they may also constitute a danger to public health, particularly in island ecosystems. Fecal samples were collected from 205 dogs and 115 cats on the islands of São Miguel and Terceira, Azores archipelago (Portugal), using the Willis flotation technique and modified Baermann method, for further analysis. The overall prevalence of gastrointestinal parasitism in dogs was 53%, with the following results: Ancylostomatidae (hookworms) (42.44%), Trichuris vulpis (17.56%), Toxocara canis (12.68%) and Cystoisospora spp. (4.39%). In cats, the overall prevalence was also 53%, with the following results: Toxocara cati (31.3%), Ancylostomatidae (30.43%), Cystoisospora spp. (14.78%) and Trichuris sp. (0.87%). The prevalence of lungworms was 0.49% in canines and 20.87% in felines, with Angiostrongylus vasorum and Aelurostrongylus abstrusus species being detected in dogs and cats, respectively. The present survey detected a high prevalence of gastrointestinal infection, in both dogs and cats, probably because the samples came mainly from kennels and catteries and due to the peculiar climatic conditions in this insular territory, with mild temperature and high relative humidity. A considerable prevalence of aelurostrongylosis was also detected (20.87%), so it should be included in the list of differential diagnoses of diseases concerning the respiratory tract in cats of the archipelago.

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

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

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

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

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

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

Clinical, Radiological, and Echocardiographic Findings in Cats Infected by Aelurostrongylus abstrusus

Cats infected by Aelurostrongylus abstrusus may show a plethora of clinical signs, and pulmonary hypertension (PH) seems to be one of the possible alterations induced by the infection; however, data on this association are scant and contradictory. Therefore, the aims of this study were to investigate the association between aelurostrongylosis and PH and to evaluate the correlation between the number of A. abstrusus larvae expelled in the faeces and the clinical, echocardiographic, and radiological alterations. Fifteen cats (i.e., eight males and seven females) older than 3 months and naturally infected by A. abstrusus with different parasitic loads, expressed as larvae per grams of faeces (l.p.g.), were enrolled in the study. Each animal underwent clinical, echocardiographic, and radiographic examinations. Most cats (i.e., 10/15) showed pathological patterns on thoracic radiograms; particularly, the alveolar pattern (four cats), interstitial-nodular pattern (five cats), and bronchial pattern (one cat). No significant echocardiographic findings of PH were detected. No correlation between the number of l.p.g. and the severity of clinical signs was observed, but a significant correlation with activated partial thromboplastin time (aPTT), radiographic alterations (interstitial nodular pattern), and ultrasonographic findings (RIVIDs) were noticed. These findings suggest that other factors such as animal age and health status, as well as comorbidity, may influence the presentation of the disease or the clinical manifestation and severity of the disease.

Ultrasonography of Parasitic Diseases in Domestic Animals: A Systematic Review

Simple Summary

The aim of this literature review was to summarize the current knowledge on the application of ultrasonography in diagnosis, staging and monitoring of helminthic diseases in domestic animals. We selected and analyzed 122 papers about the application of ultrasonography in parasitic disease in ruminants, equids, swine, and companion animals. Helminths can be recognized in ultrasound images by their morphology, size, and location. In some cases, the parasites are not directly seen by ultrasound, but the lesions caused by them can be easily visualized. Ultrasound imaging is taking on an increasingly important role in veterinary parasitology.

Abstract

The aim of this review was to summarize the current knowledge on the application of ultrasonography in diagnosis, staging and monitoring of helminthic diseases in domestic animals. Only peer reviewed papers written in English language were included in this systematic review. All papers concerning unicellular parasites, wild animals, non-domestic experimental animals, or ex vivo or in vitro applications of ultrasonography were excluded from the review. A total of 122 papers met the inclusion criteria. Among them 47% concerned nematodes, 37% cestodes, and 16% trematodes with the genus Dirofilaria, Echinococcus, and Fasciola the most represented, respectively. Helminths can be recognized in ultrasound images by their morphology, size, and location. In some cases, the parasite stages are not directly seen by ultrasound, but the lesions caused by them can be easily visualized. Ultrasound imaging is taking on an increasingly important role in the diagnosis, staging, monitoring, and control of parasitic diseases in veterinary medicine. However, it cannot replace the clinical approach and the diagnostic tests commonly used in veterinary parasitology.

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.

Left Pulmonary Artery Coarctation Associated with Pneumonia and Pulmonary Hypertension in a Cat

A five-month-old European shorthair female kitten was referred because of recurrent episodes of respiratory distress. Results of physical examination, thoracic radiography, and echocardiography led to a presumptive diagnosis of severe precapillary pulmonary hypertension (PH) and interstitial pneumonia associated with right-sided cardiac remodeling. The cat rapidly died because of respiratory insufficiency. Pulmonary and cardiovascular pathological findings evidenced left pulmonary artery coarctation, severe right-sided cardiac hypertrophy, and bilateral pneumonia. This is the first report of pulmonary artery coarctation associated with pneumonia and PH in a cat.

Airway Remodeling in Feline Lungs

Airway remodeling encompass structural changes that occur as the result of chronic injury and lead to persistently altered airway structure and function. Although this process is known in several human respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD), airway remodeling is poorly characterized in the feline counterpart. In this study, we describe the spontaneous pulmonary changes in 3 cats paralleling the airway remodeling reported in humans. We observed airway smooth muscle cells (ASMCs) hyperplasia (peribronchial and interstitial), airway subepithelial and interstitial fibrosis, and vascular remodeling by increased number of vessels in the bronchial submucosa. The hyperplastic ASMCs co-expressed α-SMA, vimentin and desmin suggesting that vimentin, which is not normally expressed by ASMCs, may play a role in airway thickening, and remodeling. ASMCs had strong cytoplasmic expression of TGFβ-1, which is known to contribute to tissue remodeling in asthma and in various bronchial and interstitial lung diseases, suggesting its involvement in the pathogenesis of ASMCs hyperplasia. Our findings provide histologic evidence of airway remodeling in cats. Further studies on larger caseloads are needed to support our conclusions on the value of this feline condition as an animal model for nonspecific airway remodeling in humans.

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.

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

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

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

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

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.

Felid Cardiopulmonary Nematodes: Dilemmas Solved and New Questions Posed

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