Concept: Angiostrongylus vasorum
BACKGROUND: Dirofilaria immitis and Angiostrongylus vasorum are both important potentially fatal canine nematodes with overlapping endemic areas, especially in Europe. The preadult and adult stages of both species are living in the Arteria pulmonalis and the right heart, and diagnostically detectable circulating parasite antigens have been demonstrated for both species. For the detection of D. immitis infections, a variety of commercial tests have been developed, however, they have not been evaluated for cross-reactions against circulating antigens of A. vasorum. METHODS: In this study, potential cross-reactions of sera from 16 dogs, which were experimentally infected with A. vasorum and which had circulating antigens as confirmed by a species-specific ELISA, were evaluated for the detection of A. vasorum antigen in six commercially available D. immitis test kits. RESULTS: In three fast tests (Witness® Dirofilaria, SensPERT® Canine Heartworm, SNAP® 4Dx® Plus), all sera were negative. One fast membrane ELISA (SNAP® HTWM RT Test) was positive with four sera (25 %), and one serum delivered a non-valid result twice. In the PetChek® HTWM PF Test, depending on the interpretation protocol, 5 or 8 dogs (31.2 – 50 %) were positive. With the DiroCHEK®-ELISA, a single A. vasorum-infected dog (6.2 %) tested positive. CONCLUSIONS: Due to potential cross-reactions with A. vasorum in commercially available test kits for the detection of D. immitis antigen, the simultaneous use of highly specific diagnostic methods for the differentiation of these two canine heart worms is recommended.
SUMMARY Molecular phylogeography has revolutionised our ability to infer past biogeographic events from cross-sectional data on current parasite populations. In ecological parasitology, this approach has been used to address fundamental questions concerning host-parasite co-evolution and geographic patterns of spread, and has raised many technical issues and problems of interpretation. For applied parasitologists, the added complexity inherent in adding population genetic structure to perceived parasite distributions can sometimes seem to cloud rather than clarify approaches to control. In this paper, we use case studies firstly to illustrate the potential extent of cryptic diversity in parasite and parasitoid populations, secondly to consider how anthropogenic influences including movement of domestic animals affect the geographic distribution and host associations of parasite genotypes, and thirdly to explore the applied relevance of these processes to parasites of socio-economic importance. The contribution of phylogeographic approaches to deeper understanding of parasite biology in these cases is assessed. Thus, molecular data on the emerging parasites Angiostrongylus vasorum in dogs and wild canids, and the myiasis-causing flies Lucilia spp. in sheep and Cochliomyia hominovorax in humans, lead to clear implications for control efforts to limit global spread. Broader applications of molecular phylogeography to understanding parasite distributions in an era of rapid global change are also discussed.
Angiostrongylus vasorum is a highly pathogenic metastrongylid nematode affecting dogs, which uses gastropod molluscs as intermediate hosts. The geographical distribution of the parasite appears to be heterogeneous or patchy and understanding of the factors underlying this heterogeneity is limited. In this study, we compared the species of gastropod present and the prevalence of A. vasorum along a rural-urban gradient in two cities in the south-west United Kingdom.
In the last decade serological tests for detection of circulating Angiostrongylus vasorum antigen and specific antibodies have been developed and adopted for individual diagnosis and epidemiological studies in dogs. Although confirmed positive at necropsy, antigen detection was not possible in single experimentally, as well as naturally infected dogs, possibly due to immune complex formation. The aim of this study was to evaluate the effect of heat treatment on detection of A. vasorum antigen in sera of experimentally (n = 21, 119 follow-up sera) and naturally (n = 18) infected animals. In addition, sera of dogs showing clinical signs consistent with angiostrongylosis (n = 10), of randomly selected dogs (n = 58) and of dogs with other parasitic infections (n = 15) were evaluated. Sera were subjected to heat treatment at 100 °C after addition of 0.5 M EDTA (dilution 1:5) and tested with ELISAs for detection of circulating A. vasorum antigen before and after treatment.
Angiostrongylus vasorum is a nematode residing in the heart and pulmonary vessels of dogs and wild carnivores. In Europe the red fox is its reservoir, while only three records from wolves have been published. Angiostrongylus vasorum has a worldwide distribution, and many pieces of evidence demonstrate that it is spreading from endemic areas to new ones. In Italy, A. vasorum was reported with increasing frequency in dogs and foxes in the last decades, and now it is considered endemic throughout the country. Angiostrongylus vasorum can be asymptomatic or cause respiratory and circulatory disorders, at times causing severe disseminated infections.
Angiostrongylus vasorum is the causative agent of canine angiostrongylosis, a severe snail-borne disease of dogs. Red foxes are important natural reservoirs of infection, and surveys of foxes provide a more objective picture of the parasite distribution. Our aim was to investigate the possibility of the presence of A. vasorum in red foxes from the western part of Romania and to analyse the risk factors related to the sex, age and geographic origin of the foxes. Between July 2016 and April 2017, 567 hunted red foxes from 10 counties of western Romania were examined by necropsy for the presence of lungworms.
In Italy, Angiostrongylus vasorum, an emergent parasite, is being diagnosed in dogs from areas considered free of infection so far. As clinical signs are multiple and common to other diseases, its diagnosis can be challenging. In particular, in areas where angiostrongylosis and dirofilariosis overlap, a misleading diagnosis of cardiopulmonary dirofilariosis might occur even on the basis of possible misleading outcomes from diagnostic kits.
Angiostrongylus vasorum (A. vasorum) is an important emerging disease of canidae. Cardiorespiratory signs are common in affected dogs, therefore thoracic imaging is critical for diagnosing and monitoring disease. Descriptions of thoracic computed tomography (CT) findings in dogs naturally infected with A. vasorum are currently lacking. Aims of this multicenter, retrospective study were to describe thoracic CT findings in a group of dogs with confirmed disease, determine whether any changes were consistent among dogs, and propose standardized terms for describing thoracic CT findings. Nine UK-based referral centers' clinical and imaging databases were searched for dogs that had a confirmed diagnosis of A. vasorum, and had undergone thoracic CT examination. Eighteen dogs, from seven of the centers, fulfilled the inclusion criteria. The lung lobes were divided into the following three zones and the CT changes described in each: pleural (zone 1), subpleural (zone 2), and peribronchovascular (zone 3). The predominent abnormality was increased lung attenuation due to poorly defined ground-glass opacity or consolidation. There were regions of mosaic attenuation due to peripheral bronchiectasis. Nine/18 (50%) dogs showed hyperattenuating nodules of varying sizes with ill-defined margins. The distribution always affected zones 1 and 2 with varied involvement of zone 3; this resulted in clear delineation between zones 2 and 3. Tracheobronchial lymphadenomegaly was frequently noted. Findings were nonspecific and there was considerable overlap with other pulmonary conditions. However, authors recommend that A. vasorum be considered a likely differential diagnosis for dogs with a predominantly peripheral distribution of lung changes.
Angiostrongylus vasorum infections are the cause of severe cardiopulmonary diseases in dogs. In the past, canine angiostrongylosis has largely been neglected in Europe, although some recent studies indicated an expansion of historically known endemic areas, a phenomenon that might also apply to Crenosoma vulpis. The aim of the present study was to analyse temporal and spatial trends of canine A. vasorum and C. vulpis infections and to perform GIS-supported risk factor analysis to evaluate the role of landscape, age and seasonality in the life-cycle of these nematodes.
Phagocyte-derived extracellular traps (ETs) were recently demonstrated mainly in vertebrate hosts as an important effector mechanism against invading parasites. In the present study we aimed to characterize gastropod-derived invertebrate extracellular phagocyte trap (InEPT) formation in response to larval stages of important canine and feline metastrongyloid lungworms. Gastropod haemocytes were isolated from the slug species Arion lusitanicus and Limax maximus, and the snail Achatina fulica, and exposed to larval stages of Angiostrongylus vasorum, Aelurostrongylus abstrusus and Troglostrongylus brevior and investigated for gastropod-derived InEPT formation.