Angela Di Cesare

Canine and feline cardiopulmonary parasitic nematodes in Europe: emerging and underestimated

Cardiopulmonary nematodes of dogs and cats cause parasitic diseases of central relevance in current veterinary practice. In the recent past the distribution of canine and feline heartworms and lungworms has increased in various geographical areas, including Europe. This is true especially for the metastrongyloids Aelurostrongylus abstrusus, Angiostrongylus vasorum and Crenosoma vulpis, the filarioid Dirofilaria immitis and the trichuroid Eucoleus aerophilus (syn. Capillaria aerophila). The reasons of this emergence are little known but many drivers such as global warming, changes in vector epidemiology and movements in animal populations, may be taken into account. The purpose of this article is to review the knowledge of the most important heartworm and lungworm infections of dogs and cats in Europe. In particular recent advances in epidemiology, clinical and control are described and discussed.

Canine and Feline Infections by Cardiopulmonary Nematodes in Central and Southern Italy

Capillaria aerophila, Aelurostrongylus abstrusus, Angiostrongylus vasorum and Dirofilaria immitis are cardiopulmonary nematodes affecting dogs and cats and presently emerging in several countries. The results obtained in 2009 – 2010 during a study aiming to investigate the occurrence of these nematodes in regions from Central (Marche and Abruzzo regions – Sites A and B, respectively) and southern (Apulia – Site C) Italy are here reported. A total of 534 and 436 individual faecal samples collected from dogs and cats were examined, together with 471 and 34 faecal environmental samples taken from dog shelters and catteries. One hundred and ninety-two individual blood samples were also collected from dogs. Faeces were examined using copromicroscopical flotations and Baermann technique, whereas blood samples were tested by Knott’s method. Eggs of C. aerophila were detected in 1.48 % and 20 % (Site A), 8.67 % and 2.71 % (Site B), and 16.67 % and 0 % (Site C) of individual and environmental canine samples. C. aerophila was found in 2.90 % (Site A), 3.03 % (Site B) and 14.29 % (Site C) of individual cats. Larvae of A. vasorum were found in 0.96 % and 2.48 % of individual and environmental samples from Site B, respectively, while those of A. abstrusus in 1.82 % (Site A) and 9.96 % (Site B) of individual faeces. Microfilariae of Dirofilaria immitis, identified on the basis of key morphological and morphometric features, were detected in 2.56 % of samples collected from Site B. Despite the small sample size, these results indicate that cardiopulmonary nematodes occur in Central and southern Italy, thus they should be included in the differential diagnosis of pet cardiorespiratory diseases. Larger surveys are necessary to gain more information on the diffusion of these parasites, especially for C. aerophila and A. vasorum, for which the actual distribution is poorly known.

New Insights into Morphological and Biological Features of Capillaria aerophila (Trichocephalida, Trichuridae)

Capillaria aerophila is a trichuroid nematode affecting the respiratory system of dogs, cats, wild carnivores and, occasionally, humans. Animals become infected by ingesting larvated eggs or earthworms, which act as facultative intermediate hosts. The aim of this work is to present new insights into morphological and biological features of this neglected lungworm. Typical features of C. aerophila eggs, differentiating them from those of most known trichuroid whipworms (i.e. size, asymmetry of bipolar plugs and a wall with a network of anastomosing ridges), were detected upon light and scanning electron microscopy. Eggs of C. aerophila were used for in vitro development. Light microscopy showed typical features of C. aerophila eggs: size, asymmetry of bipolar plugs and a wall with a network of anastomosing ridges. All these features were confirmed upon SEM, in that C. aerophila eggs showed an outer densely striated and net-like shell. Eggs of T. vulpis, used for a comparative analysis, were bigger than those of C. aerophila and showed a thick and smooth wall at both light and scanning electron microscopy. Eggs started to develop after 35 days from shedding and mobile larvae were observed in the eggs after two months. The results of this study provide key information on the biological cycle of C. aerophila and present key morphological characters for the identification of eggs in faeces.

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.

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

Clinical features and conventional and molecular diagnostic procedures have been investigated and evaluated for the infection caused by the lungworm Aelurostrongylus abstrusus (Nematoda, Strongylida). Individual fecal samples from all cats living in a colony with suspected lungworm infection underwent coprological flotation with sugar and zinc sulfate solution and the Baermann migration method. Also, pharyngeal swabs collected for each animal were subjected to a diagnostic nested PCR assay specific for a region internal to the ribosomal Internal Transcribed Spacer 2 of A. abstrusus. Eighteen animals were positive at the Baermann method, while 12 and ten out of them were negative when feces were subjected to the flotation with sugar and zinc sulfate solution, respectively. The nested PCR assay yielded positive results when using the pharyngeal swabs from the 18 coprologically positive cats and from six more cats which were coprologically negative, thus indicating an overall infection rate of 24.4%. Twenty-two out of 24 infected cats showed clinical respiratory symptoms and the most common were general respiratory distress, cough, wheezing, sneezing, and nasal discharge. These results indicate that cat aelurostrongylosis is of clinical importance and, thus, needs to be included in differential diagnosis of feline respiratory diseases. The importance of the disease is discussed together with pros and cons of different conventional and innovative diagnostic approaches.

Infection by Eucoleus aerophilus in dogs and cats: is another extra-intestinal parasitic nematode of pets emerging in Italy?

The occurrence of the infection by the lungworm Eucoleus aerophilus (syn. Capillaria aerophila) in dogs and cats from Italy has been evaluated with conventional diagnostic procedures. Individual faecal samples from 569 dogs and 200 cats were undertaken to faecal flotation with sugar and zinc sulphate solution. Sixteen dogs (2.8%) and 11 cats (5.5%) scored positive for eggs of E. aerophilus when samples were processed with either of the two flotation solutions. Overall 14 of 16 dogs and eight of 11 cats infected by E. aerophilus showed respiratory symptoms and the most common were general respiratory distress, dry cough, wheezing and sneezing. These results indicate that E. aerophilus is not uncommon and that canine and feline capillariosis is of clinical importance. Given the impact that E. aerophilus infections may have upon animal health and its zoonotic potential, it is strongly advisable to routinely include this disease in the differential diagnosis of (cardio)-respiratory diseases of dogs and cats.

Environmental contamination by canine geohelminths

Intestinal nematodes affecting dogs, i.e. roundworms, hookworms and whipworms, have a relevant health-risk impact for animals and, for most of them, for human beings. Both dogs and humans are typically infected by ingesting infective stages, (i.e. larvated eggs or larvae) present in the environment. The existence of a high rate of soil and grass contamination with infective parasitic elements has been demonstrated worldwide in leisure, recreational, public and urban areas, i.e. parks, green areas, bicycle paths, city squares, playgrounds, sandpits, beaches. This review discusses the epidemiological and sanitary importance of faecal pollution with canine intestinal parasites in urban environments and the integrated approaches useful to minimize the risk of infection in different settings.

Efficacy and Safety of Imidacloprid 10%/Moxidectin 1% Spot-on Formulation in the Treatment of Feline Aelurostrongylosis

The objective of the present study was to evaluate the efficacy and safety of the antiparasitic spot-on formulation containing imidacloprid 10%/moxidectin 1% (Advocate®, Bayer) in the treatment of natural feline infection with the lungworm Aelurostrongylus abstrusus (Nematoda, Strongylida). The efficacy of Advocate® administered once was tested in comparison to a control oral formulation containing fenbendazole 18.75% (Panacur® Intervet) administered over three consecutive days based on larvae per gramme of faeces (LPG), measured on days 28 ± 2 following treatment and compared to counts on days −6 to −2. In total 24 cats treated either with Advocate® (n = 12) or with Panacur® (n = 12) were included. Mean LPG postbaseline (days 28 ± 2) were low in both treatment groups, i.e., 0 LPG for Advocate® and 1.3 LPG for Panacur®. Reduction of post-baseline larval counts showed Advocate® (100% reduction) to be superior in efficacy compared to the control product (99.29% reduction). No treated animals showed adverse events. This trial demonstrated that both Advocate® spot-on formulation and Panacur® oral paste are safe and effective in the treatment of aelurostrongylosis in cats. Future practical perspectives in feline medicine and the major advantages of the spot-on product compared to the oral paste are discussed.

Molecular Detection of Capillaria aerophila, an Agent of Canine and Feline Pulmonary Capillariosis

ABSTRACT Capillaria aerophila, a trichuroid nematode causing pulmonary infections in wild and domestic carnivores, is occasionally and potentially poorly recognized in infections of humans due to clinicopathological mimicry and a lack of accurate, robust laboratory diagnostics. The present work evaluated the efficiency of a DNA-based assay amplifying a partial cytochrome c oxidase subunit 1 (cox1) gene of C. aerophila in the diagnosis of lung capillariosis. Fecal samples from 34 dogs and 10 cats positive at parasitological examination for C. aerophila and other endoparasites (i.e., other lungworms, whipworms, roundworms, hookworms, tapeworms, and/or coccidia) and from 44 animals negative for C. aerophila but positive for other endoparasites were molecularly examined. Of the 44 samples positive for C. aerophila at copromicroscopy, 43 scored positive (i.e., 33/34 dogs and 10/10 cats) in seminested PCR, resulting in a sensitivity of 97 to 100%. Samples that were copromicroscopy negative for C. aerophila although positive for other endoparasites never produced a PCR product or nonspecific amplicons. The specific PCR amplification of C. aerophila (i.e., specificity of 100%) was confirmed by a nucleotide sequence analysis of the cox1 amplicons. The potential implications of the molecular diagnosis of lung capillariosis are discussed.

Development of the feline lungworms Aelurostrongylus abstrusus and Troglostrongylus brevior in Helix aspersa snails.

Aelurostrongylus abstrusus (Strongylida, Angiostrongylidae) and Troglostrongylus brevior (Strongylida, Crenosomatidae) are regarded as important lungworm species of domestic felids, with the latter considered an emerging threat in the Mediterranean region. The present study aimed to assess their concurrent development in the mollusc Helix aspersa (Pulmonata, Helicidae). Thirty snails were infested with 100 first-stage larvae (L1) of A. abstrusus and T. brevior, isolated from a naturally infested kitten. Larval development was checked by digesting five specimens at 2, 6 and 11 days post infestation. Larvae retrieved were morphologically described and their identification was confirmed by specific PCR and sequencing. All H. aspersa snails were positive for A. abstrusus and T. brevior, whose larval stages were simultaneously detected at each time point. In addition, snails were exposed to outdoor conditions and examined after overwintering, testing positive up to 120 days post infestation. Data herein presented suggest that A. abstrusus and T. brevior develop in H. aspersa snails and may eventually co-infest cats. Data on the morphology of both parasitic species in H. aspersa provide additional information on their development and identification, to better understand the population dynamics of these lungworms in receptive snails and paratenic hosts.