Angiostrongylus species in wild carnivores in the Iberian Peninsula

Angiostrongylus dujardini infection in a coconut lorikeet (Trichoglossus haematodus) from a zoological garden in Switzerland

Angiostrongylus spp. (Metastrongyloidea) can cause severe disease in several animal species and humans. This report describes an infection with Angiostrongylus dujardini in a captive coconut lorikeet (Trichoglossus haematodus) from a zoo in Switzerland. The bird was reported being attacked by conspecifics, removed from the flock, and hospitalized. It showed lethargy, moderately reduced body condition, and lack of reaction to visual stimuli. Analgesic and antibiotic treatment were initiated but because of worsening of its general condition, the bird was euthanized the following day. Necropsy revealed multifocal, subcutaneous hemorrhages, diffusely reddened lungs and a moderately dilated right heart with several intraluminal nematodes embedded in a coagulum. Four worms were collected and microscopically examined. They were identified as adult females, measuring 19-21 mm long x 0.4-0.5 mm wide, with general morphological and morphometric characteristics consistent with angiostrongylid nematodes. In lung sections, multifocal collection of thin-walled embryonated eggs in variable stages of development was observed along with fully developed nematode larvae within the lumina of alveoli and lung vessels. Associated granulomatous infiltrates indicated a severe, multifocal, chronic, granulomatous pneumonia. The diagnosis of A. dujardini infection was formulated by morphological examination of adult and larval stages, supported by molecular analysis (PCR-amplification and sequencing of the ITS2, 5.8S and 28S rDNA flanking regions). This is the first report of A. dujardini infection in an avian species, providing evidence that birds can serve as accidental hosts of this parasite in addition to mammals, and that the parasite can reach maturity and multiply in the avian cardiorespiratory system.

A Taq-Man-based multiplex quantitative PCR for the simultaneous detection and quantification of Angiostrongylus vasorum, Crenosoma vulpis, and species of respiratory capillarids in canids

In recent years, Angiostrongylus vasorum, Crenosoma vulpis, Eucoleus aerophilus (syn. Capillaria aerophila) and Eucoleus boehmi (syn. Capillaria boehmi), commonly referred to as canine lungworms, have gained a growing interest worldwide as the result of their geographical expansion. Each of these nematode species differs considerably in its biology and pathogenicity. Despite their impact on dogs' health, these parasites are often underdiagnosed owing to diagnostic challenges. Here, we describe the development and validation of a Taq-Man-based multiplex quantitative PCR (qPCR) for the simultaneous detection of the main species of canine lungworms in faeces of infected dogs. Using 10-fold serial dilutions of synthetic gene block fragments containing individual sequence targets of each lungworm species, the analytical sensitivity of the assay ascertained was 1.84 ng/μl for A. vasorum, 3.08 ng/μl for C. vulpis and 0.79 ng/μl for Eucoleus spp. The sensitivity of the assays and their ability to detect mixed species infections were compared with microscopy-based techniques (faecal floatation and Baermann technique) applied to faecal samples submitted for lungworm testing through an accredited diagnostic laboratory at the Institute of Parasitology, University of Zurich, Switzerland, and from community dogs as part of a research project on canine endoparasites in Cambodia. The multiplex qPCR displayed high diagnostic sensitivity (42/46, 91.3%; 95% Confidence Interval (CI): 79.1-97.1%) and a diagnostic specificity of 100% (45/45, 95% CI: 90.6-100%), and was able to detect 42.9% additional mixed lungworm species infections compared with microscopy-based methods. Kappa statistics showed substantial agreement between the qPCRs and microscopy for mixed infections (κ = 0.72, 95% CI: 0.4-1) and Eucoleus spp. (κ = 0.65, 95% CI: 0.45-0.85) and almost perfect agreement for C. vulpis (κ = 0.85, 95% CI: 0.63-1) and A. vasorum (κ = 0.92, 95% CI: 0.84-1). This multiplex qPCR enables timely, accurate, and sensitive diagnosis of canine lungworm species in faecal samples and can be used to monitor the geographical distribution and emergence of these parasitic species, globally.

Comparative biology of parasitic nematodes in the genus Angiostrongylus and related genera

The rise to prominence of some Angiostrongylus species through associated emerging disease in humans and dogs has stimulated calls for a renewed focus on the biology of this genus and three related genera. Although significant research efforts have been made in recent years these have tended to focus on individual species and specific aspects such as diagnosis and treatment of disease or new records of occurrence and hosts. This comprehensive review takes a comparative approach, seeking commonalities and differences among species and asking such questions as: Which species belong to this and to closely related genera and how are they related? Why do only some species appear to be spreading geographically and what factors might underlie range expansion? Which animal species are involved in the life cycles as definitive, intermediate, paratenic and accidental hosts? How do parasite larvae find, infect and develop within these hosts? What are the consequences of infection for host health? How will climate change affect future spread and global health? Appreciating how species resemble and differ from each other shines a spotlight on knowledge gaps and provides provisional guidance on key species characteristics warranting detailed study. Similarities exist among species, including the basic life cycle and transmission processes, but important details such as host range, climatic requirements, migration patterns within hosts and disease mechanisms differ, with much more information available for A. cantonensis and A. vasorum than for other species. Nonetheless, comparison across Angiostrongylus reveals some common patterns. Historically narrow definitive host ranges are expanding with new knowledge, combining with very broad ranges of intermediate gastropod hosts and vertebrate and invertebrate paratenic and accidental hosts to provide the backdrop to complex interactions among climate, ecology and transmission that remain only partly understood, even for the species of dominant concern. Key outstanding questions concern larval dynamics and the potential for transmission outside trophic relations, relations between infection and disease severity in different hosts, and how global change is altering transmission beyond immediate impacts on development rate in gastropods. The concept of encounter and compatibility filters could help to explain differences in the relative importance of different gastropod species as intermediate hosts and determine the importance of host community composition and related environmental factors to transmission and range. Across the group, it remains unclear what, physiologically, immunologically or taxonomically, delimits definitive, accidental and paratenic hosts. Impacts of infection on definitive host fitness and consequences for population dynamics and transmission remain mostly unexplored across the genus. Continual updating and cross-referencing across species of Angiostrongylus and related genera is important to synthesise rapid advances in understanding of key traits and behaviours, especially in important Angiostrongylus species that are emerging causative agents of disease in humans and other animals.

A High Prevalence of Cardiopulmonary Worms Detected in the Iberian Wolf (Canis lupus): A Threat for Wild and Domestic Canids

Simple Summary

The Iberian wolf (Canis lupus signatus) is a recognized reservoir of some zoonotic parasites that cause diseases transmissible to domestic animals and/or humans. The objective of this study was to determine the diversity of species of cardiopulmonary nematode parasites that affect wolves in northwestern Spain, and to estimate their prevalence and the relationship between these parasites and various epidemiological variables. The cardiopulmonary systems of 57 wolves from Galicia were examined using dissection and cup sedimentation techniques, and the collected worms were then morphologically identified. The overall prevalence of infection by cardiopulmonary nematodes was 24.5%, and the parasite species identified were Angiostrongylus vasorum (19.3%), Crenosoma vulpis (7%) and Eucoleus aerophilus (3.5%). The latter is of zoonotic interest. A significant relationship was found between age and C. vulpis infection, which was only found in animals under one year of age. Our findings indicate that the Iberian wolf could play an important role in maintaining cardiopulmonary parasites in the wild, and they highlight a need to identify potential risks for veterinary and public health.

Abstract

Cardiopulmonary nematodes are highly pathogenic parasites affecting domestic and wild canids. As the result of conservation programs, the Iberian wolf (Canis lupus signatus) population has recently expanded, and its distribution range covers lands from where it had long disappeared. However, the exact epidemiological role of the wolf in the life cycle of zoonotic parasites causing diseases transmissible to pets and/or humans is largely unknown. This study sought to determine the diversity of cardiopulmonary nematode parasite species that affect wolves inhabiting northwestern areas of the Iberian Peninsula, and to estimate their prevalence and the relationship between these parasites and several epidemiological variables. For this purpose, we examined the cardiopulmonary systems of 57 wolves from Galicia (from the provinces A Coruña n = 15, Lugo n = 21, Ourense n =15 and Pontevedra n = 6) using techniques of dissection and cup sedimentation. Collected worms were then identified under a light microscope according to their morphological features. Three species of nematodes were detected: Angiostrongylus vasorum (the “French-heartworm”), Crenosoma vulpis and Eucoleus aerophilus, the latter being of zoonotic interest. The prevalence was 24.5% (14/57; 95% CI 13.3–35.6%) overall, 19.3% for A. vasorum (11/57; 95% CI 8.8–29.2%), 7% for C. vulpis (4/57; 95% CI 0.4–13.6%) and 3.5% for E. aerophilus (2/57; CI −1.1–9.1%). A significant relationship (p = 0.002) was found between age and the presence of C. vulpis, which was only found in juvenile animals. Furthermore, a higher prevalence of A. vasorum and/or C. vulpis was observed in wolves with a lower body condition score (40% and 20%, respectively), though the difference was not significant (p = 0.221 and p = 0.444, respectively). Our findings indicate a high “French-heartworm” and lungworm burden in the wolf population of northern Spain, and they identify a need for studies designed to elucidate the epidemiological role played by the Iberian wolf and to identify possible risks for veterinary and public health.

Comprehensive Map of Canine Angiostrongylosis in Dogs in Spain

Canine angiostrongylosis is an emerging disease caused by Angiostrongylus vasorum, mainly affecting wild carnivores and dogs. In Spain, there are studies reporting infections in foxes, wolves, and badgers in different regions of the country. However, there are hardly any publications on its prevalence in dogs. The aim of this study was to complete and update the epidemiologic map of A. vasorum in dogs in Spain. A total of 5619 canine blood samples from all autonomous cities and provinces of Spain were collected and tested for the presence of circulating A. vasorum antigens. The overall apparent prevalence of canine A. vasorum infection in Spain was 1.39%. No significant differences were found for sex or age, but significant differences between outdoor and indoor/outdoor dogs were found. A high prevalence was also observed in the northern third of the country, where an oceanic climate prevails, being humid and rainy and where abundant vegetation can be found, thus favoring the proliferation of intermediate hosts. The results suggest that A. vasorum canine infections are heterogeneously present in a large part of the territory, demonstrating its expansion throughout the country, and therefore, awareness and prevention campaigns for this disease should be promoted.

Angiostrongylosis in Animals and Humans in Europe

Lungworms in the genus Angiostrongylus cause disease in animals and humans. The spread of Angiostrongylus vasorum within Europe and the recent establishment of Angiostrongylus cantonensis increase the relevance of these species to veterinary and medical practitioners, and to researchers in parasitology, epidemiology, veterinary science and ecology. This review introduces the key members of the genus present in Europe and their impacts on health, and updates the current epidemiological situation. Expansion of A. vasorum from localized pockets to wide distribution across the continent has been confirmed by a rising prevalence in foxes and increasing reports of infection and disease in dogs, while the list of carnivore and mustelid definitive hosts continues to grow. The tropically distributed rat lungworm A. cantonensis, meanwhile, has been recorded on islands south of Europe, previously the Canary Islands, and now also the Balearic Islands, although so far with limited evidence of zoonotic disease. Other members of the genus, namely, A. chabaudi, A. daskalovi and A. dujardini, are native to Europe and mainly infect wildlife, with unknown consequences for populations, although spill-over can occur into domestic animals and those in zoological collections. The epidemiology of angiostrongylosis is complex, and further research is needed on parasite maintenance in sylvatic hosts, and on the roles of ecology, behaviour and genetics in disease emergence. Improved surveillance in animals and humans is also required to support risk assessments and management.

Habitat Characteristics as Potential Drivers of the Angiostrongylus daskalovi Infection in European Badger (Meles meles) Populations

From 2016 to 2020, an investigation was carried out to identify the rate of Angiostrongylus spp. infections in European badgers in Hungary. During the study, the hearts and lungs of 50 animals were dissected in order to collect adult worms, the morphometrical characteristics of which were used for species identification. PCR amplification and an 18S rDNA-sequencing analysis were also carried out. Global and local spatial autocorrelation methods were used to detect high-rated and low-rated infected animal clusters. We conducted a binary logistic regression analysis along with hierarchical agglomerative clustering to determine the relation between selected biotic and abiotic variables, and the prevalence of an A. daskalovi infection. We found a high prevalence (72%) and moderate mean intensity (14.1) of Angiostrongylus sp. infection. Morphology and sequencing revealed that all animals were infected by A. daskalovi. The results of both spatial autocorrelations suggested that the spatial distribution of infected badgers was more spatially clustered than random. The results of an analysis of the correlation between habitat characteristics and infection showed that the infected animals could be associated with dry and open landscape habitats without extended and connected canopy. It is suggested that the territorial behaviour of badgers and the landscape-directed aggregation of potential intermediate hosts might be the drivers of an A. daskalovi infection.

Angiostrongylus vasorum in Domestic Dogs in Castilla y León, Iberian Peninsula, Spain

Simple Summary

Canine angiostrongylosis is a vascular and pulmonary disease caused by Angiostrongylus vasorum. In Europe, there has been an increasing number of studies showing a rise in the studies in both domestic and wild canids. In Spain, angiostrongylosis is still little-known, and studies are scarce. The aim of this study was to analyze the presence of A. vasorum in 1475 domestic dogs from the autonomous region of Castilla y León (Spain). Antigens of this species were found in 0.75% of the tested dogs, most of which lived outdoors, a significant risk factor. The geographic information system (GIS) analysis showed that the infected animals mainly lived in areas with mild temperatures and climate during most of the year and close to water bodies: stagnant water; riverbanks or irrigated areas with a predominance of alder, holm oak and gall oak forests. One main conclusion was the need to carry out more studies in countries and areas with the presence of this parasite in order to know the prevalence in dogs and wild canids, as well as determine the environmental factors that influence its presence, to be able to take more effective measures to control this disease.

Abstract

Angiostrongylus vasorum is the causative agent of canine angiostrongylosis, a disease affecting domestic and wild canids. In Europe, it is an emerging disease, mainly reported in red foxes. In Spain, there are a few studies that address the prevalence and pathology of this disease. Castilla y León is the largest region of the Iberian Peninsula, whose extensive area is 94,224 km²; however, until now, there have been no epidemiological studies on this disease. Therefore, the aim of this study was to analyze the presence of antigens of A. vasorum in 1475 dogs from Castilla y León, showing an overall prevalence of 0.75%. The infected dogs were mainly outdoors, guard and hunting breed dogs and living in locations with mild climates close to areas of high edaphic humidity, such as stagnant water, irrigated crops or riverbanks, with the vegetation dominated by alders, holm oak and gall oak forests, where the intermediate hosts develop. It is necessary to carry out more in-depth studies on the epidemiology and pathology of this disease in Spain and Europe in order to carry out efficient control in both domestic and wild animals.

First epidemiological survey of Angiostrongylus vasorum in domestic dogs from Spain

Background

Angiostrongylus vasorum is the causative agent of canine angiostrongylosis, a disease that mainly affects domestic dogs and other wild carnivores. In Europe, the number of infected individuals is increasing, being located in central and southern countries. In Spain, several studies have reported high prevalence of A. vasorum in wild animals. However, there are no studies addressing the current situation of the disease or its distribution in domestic dogs, and reports from veterinary personnel are very limited. Considering these facts, the objective of the present study was to evaluate the prevalence of A. vasorum in different areas of Spain.

Methods

Between November 2018 and October 2019, blood was sampled from a total of 2024 domestic dogs from six zones of Spain with a climate that favours the establishment of the disease, where all dogs included in the study lived outdoors or had regular access to areas with vegetation and none had travelled outside the study area of interest in the past year. Details about their sex and age were collected. All dogs were tested for the presence of A. vasorum circulating antigens using Angio Detect^TM.

Results

The overall prevalence of canine angiostrongylosis in the studied areas of Spain was 1.73%. No differences in overall prevalence were found between males and females, neither between age groups. Regarding eco-epidemiological areas, the highest prevalence was recorded in the zones located in the north and northwest of Spain (1.86–2.74%), which correspond to the wetter climates and most abundant vegetation, and the lowest prevalence was detected in the zones located in the center and west of Spain (0.93–0.99%).

Conclusions

Our data suggest that angiostrongylosis is present in Spain in domestic dogs where previously infected wild animals existed or where climatic conditions are favourable for the establishment of the disease.

Cardiopulmonary nematode infections in wild canids: Does the key lie on host-prey-parasite evolution?

Cardiopulmonary nematodes are among the most pathogenic parasites of domestic and wild canids. The aim of this study was to describe the species diversity, prevalence and infection intensity of these parasites in the Iberian wolf (Canis lupus signatus) and the red fox (Vulpes vulpes) in the northwest of the Iberian Peninsula. 257 foxes and 74 wolves were necropsied between 2008 and 2014. Four nematode species were identified: Angiostrongylus vasorum, Eucoleus aerophilus, Crenosoma vulpis and Filaroides hirthi. This last species was only found in wolves, being the first time that is cited worldwide in this wild canid. The overall parasite prevalence was significantly higher in foxes (70%) than in wolves (28%). Specifically, prevalences in foxes and wolves were, respectively, 43% and 22% for A. vasorum, 33% and 5% for E. aerophilus, and 30% and 9% for C. vulpis. The prevalence of F. hirthi was 16%. The A. vasorum intensity was significantly higher in foxes than in wolves. Differences between host species in the risk of infection would be associated to diverging feeding behavior, and possibly reflects a parasite-host adaptation related to host's hunting strategies and cardiorespiratory requirements. This study revealed an association between infection and environmental factors, and highlighted a wide variation in the spatial distribution of A. vasorum. Our results indicate that cardiopulmonary parasites are widespread in wild canids in northwest Spain, and further agrees with other studies indicating the expansion of A. vasorum in Europe and, therefore, the urgent need to investigate infection in dogs in sympatric areas.

A grid-cell based fecal sampling scheme reveals: land-use and altitude affect prevalence rates of Angiostrongylus vasorum and other parasites of red foxes (Vulpes vulpes)

In view of the role of foxes as a reservoir for Angiostrongylus vasorum, a nematode of the heart and lungs of dogs and foxes, its occurrence across Switzerland was investigated in foxes applying a standardized sampling scheme for fox fecal samples. In 72 study areas, which consisted of three 1-km² grid cells, a total of 1481 samples were collected by walking transects following linear features in the terrain, and analyzed by a flotation-sieving method. The overall prevalence rate of A. vasorum in fecal samples was 8.8% (95% confidence interval, CI 7.4-10.3%), being significantly higher in the Swiss Plateau (11.4%, CI. 9.4-13.8%) compared with other bioregions, and more prevalent in areas with less than 50% of cultivated land (p = 0.043). Prevalence rates increased with decreasing altitudes being significantly higher below 400 m above sea level (20.6%, 95% CI 15.2-26.9%), while all samples collected above 900 m asl were negative. Eggs of Toxocara sp. (12.1%), Taeniidae (10.5%), Capillaria spp. (8.3%), Trichuris vulpis (5.5%), hookworms (5.3%), Toxascaris leonina (1.3%) and Strongyloides sp. (0.4%) were furthermore identified. Taeniid eggs were positively and Capillaria spp. negatively associated with the amount of cultivated land. The prevalence rates based on our fecal analyses were generally lower compared with previous studies from Switzerland which were based on fox necropsies. However, the grid cell-based sampling scheme with replicable transects for fox feces collection proved to be a suitable, non-invasive method for parasitic large-scale surveys providing information on the relative infectious pressure for the local dog population.

Annotated catalogue of species of Angiostrongylus and the related genera Gallegostrongylus, Rodentocaulus and Stefanskostrongylus (Nematoda: Metastrongyloidea, Angiostrongylidae)

This catalogue is concerned with the closely related angiostrongylid genera Angiostrongylus, Gallegostrongylus, Rodentocaulus and Stefanskostrongylus. Three species, Angiostrongylus cantonensis, A. costaricensis and A. vasorum, have attracted most attention because of their importance in human and domestic animal disease. Many of the remaining species are poorly known and the number of valid taxa is unclear. The catalogue lists all nomenclaturally available and unavailable genus-group and species-group names that have been applied to the above genera and the species included in them, indicating their current nomenclatural status and providing the rigorous nomenclatural basis for future work. The catalogue lists 14 published and nomenclaturally available genus-group names, with the above four treated as valid, the other ten being junior synonyms. There are 42 published species-group names: 36 are valid, two are junior synonyms, four are nomenclaturally unavailable. One additional species, described in Chabaudistrongylus (synonym of Angiostrongylus), is listed as incertae sedis in Angiostrongylidae. Also listed are two unpublished collection names. The catalogue provides bibliographic details for all published names, and for available names provides locations of type material, details of type localities, geographic distributions and details of type and other hosts, both definitive and intermediate, to the extent known. The catalogue is a work of nomenclature, not a revisionary taxonomic work. No new names or new combinations are proposed. The apparently new family-group synonymy of Cardionematinae with Angiostrongylidae is introduced, as are four genus-group synonymies, three with Angiostrongylus and one with Stefaskostrongylus.

The helminth parasite community of European badgers (Meles meles) in Ireland

The European badger (Meles meles) is Ireland's largest terrestrial carnivore. Since first being identified as a wildlife reservoir of bovine tuberculosis in 1974 there has been an increased research focus into the behaviour of these ecologically important mammals in the Republic of Ireland (ROI). However, to date there has never been an assessment of the helminth parasite community of Irish badgers. This study of 289 badgers found helminth infection to be endemic within the sample population and we report for the first time the prevalence, abundance, intensity and aggregation of helminth infection in ROI. Eight distinct helminth taxa were recorded: Aelurostrongylus falciformis, Crenosoma melesi, Eucoleus aerophilus, Species A, Strongyloides spp., Uncinaria criniformis, and two unidentifiable but morphologically distinct nematodes. All helminths belong to the taxon Nematoda, and this is the first report of an exclusively nematode community across the badger's Eurasian distribution. Infection was not significantly influenced by the host sex, region of origin or season of sampling.

The American mink (Neovison vison) is a competent host for native European parasites

The American mink (Neovison vison) is a mustelid native to North America that was introduced in Europe and the former USSR for fur farming. Throughout the last century, accidental or deliberate escapes of mink from farms caused the establishment of stable feral populations. In fact, the American mink is considered an invasive alien species in 28 European countries. The present study evaluates the gastrointestinal and cardiopulmonary helminth fauna of the American mink in Galicia (NW Spain) to understand its role as a potential reservoir for parasites affecting other autochthonous mustelids. In the period 2008-2014, fifty American mink (35 males and 15 females) of different ages (22 immature and 28 adults) from the provinces of Lugo, Ourense and Pontevedra were captured and sacrificed. Eight parasite species were found (6 nematodes and 2 trematodes) with the following prevalences: Molineus patens (68%), Aonchotheca putorii (54%), Crenosoma melesi (10%), Aonchotheca annulosa (8%), Angiostrongylus daskalovi (6%), Aelurostrongylus spp. (2%), Troglotrema acutum (2%) and an unidentified trematode (2%). Eighty-two per cent of the mink harboured helminths, including 15 animals (30%) infected by only one parasite species, 19 (38%) by two species, 5 (10%) by three species and 2 mink (4%) by four species. All helminth species identified are native to European mustelids. Statistical models were used to evaluate if animal characteristics (age, sex and weight), date and capture area influenced the prevalence, intensity or parasite richness. Statistical differences were detected only in models for intensity of M. patens, A. putorii and C. melesi. This is the first report of Angiostrongylus daskalovi, a cardiopulmonary nematode, and A. annulosa, a gastrointestinal nematode specific of rodents, in American mink. Moreover, although the fluke T. acutum has already been cited in American mink, to our knowledge, the present study represents the first report of this trematode in the lung.

Angiostrongylus vasorum in Romania: an extensive survey in red foxes, Vulpes vulpes

Background

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.

Results

Overall, the infection with A. vasorum has been found in 24 red foxes (4.2%) originating in four counties (Mureș, Hunedoara, Sălaj and Cluj). There was no significant difference between the prevalence in males and females, between juveniles and adults and between counties.

Conclusions

This is the first report of autochthonous infections of A. vasorum in Romania, showing a relatively low prevalence and extending eastwards the known distributional range of this parasite in Europe. The presence of autochthonous cases in domestic dogs in Romania remains to be confirmed by further studies.

A rare cardiopulmonary parasite of the European badger, Meles meles: first description of the larvae, ultrastructure, pathological changes and molecular identification of Angiostrongylus daskalovi Janchev & Genov 1988

Background

Angiostrongylus daskalovi is a rare cardiopulmonary nematode infecting badgers. The parasite was described in 1988 and, since then, found only once in mustelids in Europe. The present study aims to report new cases of patent A. daskalovi infection in badgers from northern Romania and to provide new information on its ultrastructure, molecular diagnosis, and pathology.

Methods

Eight road-killed or hunted badgers originating from Maramureș and Alba counties in Romania were collected and necropsied. Adults and larvae of cardio-pulmonary nematodes were collected and examined by light and scanning electron microscopy (SEM). Genomic DNA was extracted from adults and first-stage larvae (L1). PCR amplification of the internal transcribed spacer 2 (ITS2, ∼500 bp) of the rRNA gene was performed. Amplicons were purified, sequenced, and compared to those available in the GenBank database. Histopathological examination of the lungs was performed and lesions described.

Results

The necropsy revealed the presence of nematodes in the pulmonary arteries of three animals. All parasites were mature adults and the coproscopic examination showed the presence of eggs and L1 larvae in all three positive animals. Light microscopy examination confirmed the morphological and morphometric similarity of parasites to Angiostrongylus daskalovi. SEM highlighted the typical angiostrongylid structure of the rays of the copulatory bursa and the anterior extremity, with the presence of six sensory papillae surrounding the mouth opening in which a triangular tooth was visible. The first-stage larva (L1) of A. daskalovi is described here for the first time. Histopathological examination of the lungs showed chronic interstitial verminous pneumonia due to the presence of adult parasites. Molecular analysis showed 100 % nucleotide similarity to an Angiostrongylus sp. isolate originating from a badger from Spain, tentatively identified as A. daskalovi.

Conclusions

Our study unequivocally demonstrates the presence of A. daskalovi in European badgers from Romania, provides the first description of the larvae and reveals new data about the ultrastructure of adult parasites and their pathological impact, contributing to the understanding of the phylogenetic relationships with other congeneric species.

Angiostrongylus chabaudi (Biocca, 1957) in wildcat (Felis silvestris silvestris, S) from Romania

Angiostrongylus chabaudi is a rare cardio-pulmonary nematode infecting felids. Although almost 60 years have passed since the original description of the species in Italy, this parasite has been seldom found in domestic and wildcats in southern Europe. The present study aims to report a new case of patent A. chabaudi infection in a road-killed wildcat from Maramureș County in Northern Romania. The necropsy revealed the presence of parasites in the pulmonary arteries and the right ventricle, and the fecal examination showed the presence of L1 larvae. Parasites were morphologically and morphometrically characterized as A. chabaudi, showing 100 % nucleotide similarity to an Angiostrongylus sp. originating from a wildcat from Germany and 99 % to A. chabaudi from Italy. This study reports A. chabaudi for the first time in Eastern Europe, expanding knowledge about the distribution range of this species.

Seroprevalence of circulating Angiostrongylus vasorum antigen and parasite-specific antibodies in dogs from Portugal

Angiostrongylus vasorum is a nematode that lives in the pulmonary arteries and right cardiac ventricle of domestic dogs and wild canids. It is increasingly being reported in several European countries and North America. This parasite induces inflammatory verminous pneumonia, causing severe respiratory disease in dogs. In some instances, coagulopathies, neurological signs and even death may occur. Scant data are available regarding the occurrence of A. vasorum in Portugal. Therefore, sera of 906 shelter dogs from North to South mainland Portugal were collected. ELISAs to detect A. vasorum circulating antigen and specific antibodies against this parasite were performed. A total of six dogs [0.66 %, 95 % confidence intervals (CI) 0.24–1.43] were positive for both A. vasorum antigen and antibody detection, indicating an active infection, and 12 dogs (1.32 %, CI 0.68–2.30) were A. vasorum antibody-positive only. Regions with antigen- and antibody-positive animals overlapped and were distributed over nearly all sampled areas in the country. This is the first large-scale ELISA-based serological survey for A. vasorum in dogs from Portugal. The endemic occurrence of A. vasorum in dogs from different geographical areas of Portugal is therefore confirmed.

Detection of Angiostrongylus vasorum in Red Foxes (Vulpes vulpes) from Brandenburg, Germany

Angiostrongylus (A.) vasorum is a nematode that causes angiostrongylosis in domestic and wild canids. Red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) are suspected of providing a wildlife reservoir for A. vasorum infections in pet dogs. To obtain data on the occurrence of A. vasorum in wildlife, red fox and raccoon dog carcasses (hunted or found dead) were collected from January to September 2009 in the Federal State of Brandenburg, Germany. Lung tissue samples were subjected to DNA extraction and examined for the presence of A. vasorum DNA by means of real-time PCR. A. vasorum DNA was detected in 11 out of 122 (9.0 %) lungs of red foxes and in none of the lung samples of raccoon dogs. These data suggest that red foxes are a reservoir of A. vasorum infections for pet dogs in this area.

Cardiopulmonary helminths in foxes from the Pyrenees

The present survey was carried out to investigate the prevalence of cardiopulmonary helminths in red foxes in Pyrenees area and to evaluate the role of foxes in the eco-epidemiology of these nematodes. Hearts and entire respiratory tracts were obtained from 87 foxes from Vall d'Aran region, Pyrenees, Catalonia, north-eastern Spain. The cardiopulmonary tracts were dissected, flushed and examined for nematodes using sedimented flushing water. Of the 87 examined foxes, 53 (61%) were positive for cardiopulmonary helminths. The identified nematodes were Crenosoma vulpis (44.8%), Eucoleus aerophilus (29.9%) and Angiostrongylus vasorum (3.4%). Statistical differences were observed only on comparing age and C.vulpis prevalence, with young foxes being more infected than adults. The high prevalence of cardiopulmonary nematodes suggested that red foxes may play an important role in their transmission and maintenance in the studied area.

Species of Angiostrongylus (Nematoda: Metastrongyloidea) in wildlife: A review

Twenty-one species of Angiostrongylus plus Angiostrongylus sp. (Nematoda: Metastrongyloidea) are known currently in wildlife. These occur naturally in rodents, tupaiids, mephitids, mustelids, procyonids, felids, and canids, and aberrantly in a range of avian, marsupial and eutherian hosts including humans. Adults inhabit the pulmonary arteries and right atrium, ventricle and vena cava, bronchioles of the lung or arteries of the caecum and mesentery. All species pass first-stage larvae in the faeces of the host and all utilise slugs and/or aquatic or terrestrial snails as intermediate hosts. Gastropods are infected by ingestion or penetration of first-stage larvae; definitive hosts by ingestion of gastropods or gastropod slime. Transmission of at least one species may involve ingestion of paratenic hosts. Five developmental pathways are identified in these life cycles. Thirteen species, including Angiostrongylus sp., are known primarily from the original descriptions suggesting limited geographic distributions. The remaining species are widespread either globally or regionally, and are continuing to spread. Small experimental doses of infective larvae (ca. 20) given to normal or aberrant hosts are tolerated, although generally eliciting a granulomatous histopathological response; large doses (100-500 larvae) often result in clinical signs and/or death. Two species, A. cantonensis and A. costaricensis, are established zoonoses causing neurological and abdominal angiostrongliasis respectively. The zoonotic potential of A. mackerrasae, A. malaysiensis and A. siamensis particularly warrant investigation. Angiostrongylus cantonensis occurs in domestic animals, mammalian and avian wildlife and humans in the metropolitan areas of Brisbane and Sydney, Australia, where it has been suggested that tawny frogmouths and brushtail possums may serve as biosentinels. A major conservation issue is the devastating role A. cantonensis may play around zoos and fauna parks where captive rearing of endangered species programmes may exist and where Rattus spp. are invariably a problem.

Angiostrongylus chabaudi Biocca, 1957: a new parasite for domestic cats?

Background

Natural infection with a species of Angiostrongylus has been reported only once in wildcats from central Italy by Biocca in 1957. The causative species of this infection was identified as Angiostrongylus chabaudi. Following this report, this parasite had never been found in either wild or domestic cats.

Findings

The lungs and the pulmonary arteries of an adult female cat (Felis silvestris catus), road-killed in Sardinia, Italy, were macroscopically examined and dissected under a light microscope for the presence of parasites. A slender nematode was detected and its morphometrical features were consistent with those of A. chabaudi. Morphological data were supplemented by sequencing of the partial cytochrome oxidase c subunit 1 (cox1) gene, as well as the internal transcribed spacer 2 (ITS2) of the rDNA. Nucleotide sequences displayed 99% homology with the ITS2 sequence [GenBank KM216825.1] of a specimen of Angiostrongylus sp. recovered recently from the pulmonary artery of a wildcat in Germany and 91% with cox1 sequence [GenBank GU138118.1] of Angiostrongylus vasorum.

Conclusion

The results of the present study indicate, for the first time, that A. chabaudi may also infect domestic cats, and thus should be considered in the diagnosis of metastrongyloid species infecting their cardio-pulmonary system.

Recent advances in the epidemiology, clinical and diagnostic features, and control of canine cardio-pulmonary angiostrongylosis

The aim of this review is to provide a comprehensive update on the biology, epidemiology, clinical features, diagnosis, treatment, and prevention of canine cardio-pulmonary angiostrongylosis. This cardiopulmonary disease is caused by infection by the metastrongyloid nematode Angiostrongylus vasorum. The parasite has an indirect life cycle that involves at least two different hosts, gastropod molluscs (intermediate host) and canids (definitive host). A. vasorum represents a common and serious problem for dogs in areas of endemicity, and because of the expansion of its geographical boundaries to many areas where it was absent or uncommon; its global burden is escalating. A. vasorum infection in dogs can result in serious disorders with potentially fatal consequences. Diagnosis in the live patient depends on faecal analysis, PCR or blood testing for parasite antigens or anti-parasite antibodies. Identification of parasites in fluids and tissues is rarely possible except post mortem, while diagnostic imaging and clinical examinations do not lead to a definitive diagnosis. Treatment normally requires the administration of anthelmintic drugs, and sometimes supportive therapy for complications resulting from infection.

Extraintestinal nematodes of the red foxVulpes vulpesin north-west Italy

Extraintestinal nematodes of the red fox (Vulpes vulpes) are a wide group of parasites that infect wild and domestic carnivores and occasionally humans. Nematodes in the cardiopulmonary system, stomach, urinary apparatus and muscle tissue of 165 red foxes (Vulpes vulpes) from north-west Italy (Liguria and Piedmont) were investigated between 2009 and 2012. Of the cardiopulmonary nematodes, a high prevalence ofAngiostrongylus vasorumandEucoleus aerophilus(syn.Capillaria aerophila) was found, 78.2% and 41.8% respectively;Crenosoma vulpis(15.8%) andFilaroidesspp. (4.8%) were also found.Spirocerca lupi(23.5%),Aonchotheca putorii(syn.Capillaria putorii) (8.6%) andPhysalopteraspp. (2.5%) were detected in the stomach andPearsonema plica(syn.Capillaria plica) (56.8%) in the bladder.Eucoleus boehmi(syn.Capillaria boehmi)was also detected in the nasal cavities of one of the two foxes examined. A coprological examination revealed eggs ofE. aerophilus,A. putorii,S. lupi,Physalopteraspp. and eggs of intestinal parasites. Filarial worms were absent in all the 165 animals examined, nor was there evidence ofTrichinellaspp. in any of the foxes. The foxes were found to host a high prevalence of many species of extraintestinal nematodes. The prevalence ofA. vasorumin foxes found in the present study is among the highest in Europe. In addition, to the best of our knowledge,E. boehmiandFilaroidesspp. have never been reported before in this host in Italy.

Angiostrongylus vasorum in wolves in Italy

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Nematodes found in dead wolves in Rome province, Italy, were confirmed to be Angiostrongylus vasorum.

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Molecular evidence further showed homology with lungworm larvae in sympatric dogs.

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It is not known whether wolves represent ancentral hosts or are subject to more recent spill-over from dogs and foxes.

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The parasite is pathogenic, emerging, and should be borne in mind in wolf conservation programmes in endemic areas.

In the past decade, the parasitic nematode Angiostrongylus vasorum has attracted attention for its emergence in previously free areas and for the rise in clinical cases in domestic dogs. Italy is regarded as one of the countries where this potentially life-threatening parasite is spreading, especially due to bridging infections between wildlife and domestic dogs. The present article describes the presence of A. vasorum in wolves from Italy. Nematodes were observed in histological sections of three wolves found dead in Rome province, central Italy. Morphological and molecular identification of the nematodes, by polymerase chain reaction of rDNA ITS-2 and sequencing, confirmed the nematodes to be A. vasorum, with 99% genetic homology with A. vasorum from sympatric dogs. This is the second report of this species in wolves and the first in this host in Italy, and coincides with increasing records of A. vasorum in dogs and foxes in Italy. Implications for the epidemiology of this emerging parasite and for wildlife health are concisely discussed.

Parasite epidemiology in a changing world: can molecular phylogeography help us tell the wood from the trees?

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.