The common frog (Rana temporaria) as a potential paratenic and intermediate host for Angiostrongylus vasorum

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.

Wild Mesocarnivores as Reservoirs of Endoparasites Causing Important Zoonoses and Emerging Bridging Infections across Europe

Mesocarnivores are small- or mid-sized carnivore species that display a variety of ecologies and behaviours. In Europe, wild mesocarnivores are represented by the red fox (Vulpes vulpes), the golden jackal (Canis aureus), the European wildcat (Felis silvestris), the Mustelidae of the genera Meles, Martes, Mustela, Lutra, the invasive species of raccoon dog (Nyctereutes procyonoides), raccoons (Procyon lotor), and American mink (Neogale vison). These abundant animals thrive in various habitats and often develop their activity close to human settlements. Thus, they may play an important role in the introduction, maintenance, and transmission of major parasitic zoonoses and promote bridging infections with domestic animals. Against this background, this article reports and discusses some of the most important endoparasites of wild mesocarnivores living in Europe, on the basis of their actual role as reservoirs, spreaders, or sentinels. The data derived from epizootiological studies in different European countries, and the proven or speculated implications of the detected endoparasites in human and domestic animals' health, are discussed. Through older and recent literature review, the state-of-the-art knowledge on the occurrence and prevalence of the parasites under consideration is presented, showing further, warranted investigations and the need for surveillance and vigilance.

Angiostrongylus vasorum in Estonia: Multi-center study in dogs with clinical signs suggestive of canine angiostrongylosis, survey of potential risk behaviors among the dogs, and questionnaire survey of knowledge about the parasite among veterinarians

Angiostrongylus vasorum is a parasite that can cause life-threatening disease in dogs. In recent years, A. vasorum has been reported spreading into new areas, in particular towards northeastern Europe. Despite being detected in wildlife in Estonia, no studies have focused on A. vasorum in domestic dogs in the country. We conducted a multi-center study in 2018-2019: at eight small animal clinics, altogether 115 dogs that had clinical signs that could be suggestive of canine angiostrongylosis were enrolled for testing using a commercial A. vasorum antigen detection test. In addition, we collected information on potential risk behaviors for acquiring A. vasorum infection - eating potential intermediate hosts and paratenic hosts - among the dogs, using a questionnaire for dog owners. Moreover, we surveyed knowledge about A. vasorum among veterinarians authorized to work in Estonia. None (0.0%, 95% confidence interval 0.0-2.6) of the 114 dogs included in the study tested A. vasorum antigen positive. Two (2.0%) of the 102 dogs included in the risk behavior analysis had been seen to eat slugs and/or snails, and this behavior was considered possible for further 17 (16.7%) of the dogs. Four (3.9%) of the dogs had been seen to eat frogs, and this behavior was considered possible for further 14 (13.7%) of the dogs. Thirty-eight (90.5%) of the 42 veterinarians who participated in the questionnaire survey selected the correct host and 28 (66.7%) selected the correct vectors of the parasite, from the provided options. Our results indicate that A. vasorum was either not established or not common in dogs in Estonia in 2018-2019, but this needs to be interpreted with caution due to the limited sample size, possible false negative results in recently infected dogs and the limited sensitivity of the test applied. Most local veterinarians seemed to know the parasite, and this awareness and knowledge among veterinarians should be maintained and further improved. Taken the presence of the parasite in local wildlife, it is prudent to include A. vasorum infection in the list of differential diagnoses for dogs with clinical signs that could be suggestive of canine angiostrongylosis in Estonia.

The current situation of Angiostrongylus vasorum in Romania: a national questionnaire-based survey

Background

Angiostrongylus vasorum (Nematoda, Metastrongyloidea) is a vascular nematode that resides in the pulmonary arteries and the right side of the heart of a wide variety of carnivores, with an indirect life cycle using coprophagic gastropods as intermediate hosts. For domestic dogs, the infection with A. vasorum can be asymptomatic, but more frequently, it is associated with a wide range of clinical manifestations like cardio-respiratory signs, bleedings, neurological signs, and ocular problems which can lead to death when not treated accordingly. Angiostrongylosis was confirmed for the first time in Romania in red foxes (Vulpes vulpes) in 2017 and two years later a seroepidemiologic study was conducted among domestic dogs. However, to this date, no clinical canine angiostrongylosis cases were published in Romania. The aim of the present paper was to evaluate the knowledge about canine angiostrongylosis among veterinarians in Romania and to update the distribution of this disease using a national wide anonymous questionnaire.

Results

Overall, 147 unique responses were submitted, from 31 out of 42 counties. Twelve veterinarians (8%) from 8 counties (26%) acknowledged diagnosing a case of angiostrongylosis including 5 from the Bucharest and 1 from each of the remaining seven counties. All affected dogs had respiratory distress, 75% suffered cardiopathy, 16% coagulopathies and 8% neurological signs. Case diagnosis was based mostly on larval detection by coprology (67%) and serological antigen detection test (42%).

Conclusions

Romanian veterinarians are aware of canine angiostrongylosis and a significant number have clinical experience with the disease. Epidemiological studies are now needed to assess its distribution in the country, and further efforts are required to improve understanding of the disease, its diagnostic and treatment methods among veterinarians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03034-1.

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.

Co-Occurrence of Domestic Dogs and Gastropod Molluscs in Public Dog-Walking Spaces and Implications for Infection with Angiostrongylus vasorum: A Preliminary Study

Simple Summary

Angiostrongylus vasorum is a serious parasitic disease increasing in range and prevalence in Europe. The parasite passes through land slugs and snails before it can infect dogs but contact between dogs and these intermediate hosts is not well studied. We surveyed dogs and slugs/snails in parks and on streets in an urban A. vasorum hotspot area in southern England, United Kingdom, with the aim of determining the conditions under which they overlap. We counted 1672 slugs/snails and 763 dogs across seven sites. We found that habitat types in which the hosts were present differed, with dogs occurring 15× more often on hard surfaces (e.g., concrete) than woodland/scrub, but also occurring on natural grassland. Large numbers of slugs/snails were present 5.82× more often in woodland/scrub and natural grassland than on hard surfaces. Slug and snail species at risk of a greater likelihood of infection with A. vasorum were present 65.12× more often in woodland/scrub and 62.17× more often in amenity grassland than other habitats. The results suggest that contact between dogs and slugs/snails is most likely in amenity and natural grassland but that infection risk with A. vasorum is greatest in amenity grassland and woodland/scrub.

Abstract

Angiostrongylusvasorum is a helminth parasite of domestic dogs that is increasing in range and prevalence. Its lifecycle requires terrestrial gastropod mollusc (“gastropod”) intermediate hosts, but research is lacking regarding contact risk in situ. We studied co-occurrence between dogs and gastropods in dog-walking spaces in an A. vasorum hotspot in southern England, United Kingdom, with the aim of quantifying environmental and spatio-temporal overlap. We surveyed 390 quadrats and 180 point-counts along 3 km transects at seven sites, yielding 1672 gastropod and 763 dog observations. Common gastropods comprised Arion, Cornu, Monacha, Deroceras, Tandonia, Cochlicella, and Trochulus species. Habitat was the most important factor structuring both gastropod and dog presence and abundance. Likelihood ratio comparisons from conditional probability trees revealed that dogs were 15× more likely to be present on hardstanding surfaces than other habitats but were also present on natural and amenity grassland. Presence of gastropod species associated with high A. vasorum prevalence was 65.12× more likely in woodland/scrub and 62.17× more likely in amenity grassland than other habitats. For gastropods overall, high abundance was 5.82× more likely in woodland/scrub and natural grassland. The findings suggest co-occurrence is highest in amenity and natural grassland, but infection risk is greatest in amenity grassland and woodland/scrub.

Angiostrongylus vasorum in foxes (Vulpes vulpes) and wolves (Canis lupus italicus) from Abruzzo region, Italy

In Europe wildlife animals such as the red fox (Vulpes vulpes) are considered the main reservoir for Angiostrongylus vasorum as well as a potential threat for domestic dog infection. Though this parasite is endemic in fox populations, data on A. vasorum infection in wolves (Canis lupus italicus) are still scant, having only recently been described in Northwestern Spain, in Italy, in Croatia and in Slovakia. Based on the rising number of cases of canine lungworm infection in Central Italy (Abruzzo region), the aim of the present study was to investigate the infection by A. vasorum in fox and wolf populations sharing the same geographical area of dogs. From October 2008 to November 2019, A. vasorum specimens were collected, through routine post-mortem examination, from 56 carcasses (44 foxes and 12 wolves). Adult parasites were searched for in the right side of the heart and in pulmonary artery of all carcasses. First stage of larvae (L1) was searched in faeces using the Baermann technique and in lungs by tissue impressions. Overall, 230 adult specimens were collected and identified on a morphological basis. To confirm the morphological identification, 4 adult specimens (n = 3 from fox, n = 1 from wolf) were molecularly identified as A. vasorum by amplification of partial fragment of nuclear 18S rRNA (~1700 bp) genes. The anatomo-pathological and parasitological examinations indicated the presence of A. vasorum in 33 foxes (75%) and in 8 wolves (66.7%). The level of prevalence of infested wolves was higher than the previous one reported in other European countries. Interestingly, the prevalence of infection in foxes herein recorded was higher than that described in dogs (8.9%) living in the same geographical area. This result may confirm the hypothesis that the spread of canine angiostrongylosis is linked to fox populations infection.

Efficacy of orally administered combination of moxidectin, sarolaner and pyrantel (Simparica Trio™) for the prevention of experimental Angiostrongylus vasorum infection in dogs

BACKGROUND

Infection with Angiostrongylus vasorum may cause severe clinical disease, even death in dogs, however, due to the often non-specific clinical signs, diagnosis is not always straightforward. Regular prophylactic treatment may offer a safe means to protect dogs against infection. The efficacy of a novel oral endectocide containing moxidectin, sarolaner and pyrantel was investigated for the prevention of angiostrongylosis in dogs in three placebo-controlled, randomized, masked studies. The initial study (Study 1) determined the efficacious dosage of moxidectin in the combination product by evaluating three different dose levels, and two follow-up studies (Studies 2 and 3) confirmed the efficacy of the selected moxidectin dose.

METHODS

Animals were infected orally with 200 infective third-stage larvae (L3) of A. vasorum and were treated 28 days later with the combination product or with placebo. Timing of dosing relative to infection allowed for efficacy to be evaluated against the immature adult (L5) stage. Dogs in Study 1 received treatments with oral tablets to deliver 3, 12 or 24 µg/kg moxidectin in combination with 2 mg/kg sarolaner and 5.0 mg/kg pyrantel (as pamoate salt) or placebo. In Studies 2 and 3, Simparica Trio™ tablets were administered to provide minimum dosages of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5.0 mg/kg pyrantel (as pamoate salt). Efficacy of the combination product was calculated as the percent reduction in adult worm counts at necropsy relative to placebo.

RESULTS

In Study 1, the 3, 12 and 24 µg/kg moxidectin dosage in the combination product provided 7.2%, 54.5% and 94.7% efficacy against the immature adult stages of A. vasorum, respectively. Studies 2 and 3 confirmed that the efficacy of 24 µg/kg moxidectin combined with 1.2 mg/kg sarolaner and 5 mg/kg pyrantel in Simparica Trio™ was ≥ 92.9%. All three studies established that a single oral administration of 24 µg/kg moxidectin in the combination product provided effective prophylactic treatment for angiostrongylosis, reduced L1 production and fecal excretion and minimized the tissue damage to the lungs.

CONCLUSIONS

A single oral treatment of dogs with Simparica Trio™ providing moxidectin at a minimum dose of 24 µg/kg was efficacious in the prevention of angiostrongylosis.

The 'French heartworm' in Greece: A countrywide serological survey of Angiostrongylus vasorum infection by combined detection of circulating antigens and specific antibodies

Angiostrongylus vasorum is a nematode of the superfamily Metastongyloidea and was first described in the south of France in the nineteenth century where its biology was extensively studied in the 1960ies, leading to the common use of the byname "the French heartworm". The life cycle of the parasite is indirect including slugs and snails as intermediate hosts, while the adults live in the right heart and pulmonary arteries. Since then, many studies have been conducted in different European countries. However, there is scant knowledge regarding the prevalence and distribution of this parasite in Greece. Therefore, the objective of the present study was to investigate the current seroprevalence of A. vasorum in dogs in Greece. Overall 1000 apparently healthy and randomly selected dogs, presented in veterinary clinics, were involved at national level (n = 66 locations). Individual serum samples were obtained and tested using two in-house ELISAs by combining the detection of specific antibodies against the parasite and of circulating antigens of A. vasorum. Overall, 3.0% (n = 30, CI 95% 2.1 to 4.3%) of the sampled dogs were seropositive to at least one of the two ELISAs: 0.4% (n = 4, CI 95% 0.2 to 1.0%) were positive by both ELISAs, while 1.0% (n = 10, CI 95% 0.5 to 1.8%) were seropositive only for specific antibodies and 1.6% (n = 16, CI 95% 1.0 to 2.6%) were antigen-positive only. This is the first multicentric seroepidemiological study about A. vasorum in dogs from Greece. We showed that this parasite circulates in the local canine population and further studies should be carried out to elucidate its significance in the country.

Rare Case of Angiostrongylus Vasorum Intraocular Infestation in an Asymptomatic Dog

The presented clinical observation shows an atypical case of Angiostrongylus vasorum intraocular infection in an 18-month-old male beagle from north-eastern Slovakia. The dog presented with a motile worm in the anterior chamber of the right eye. No ocular signs or symptoms of a systemic disease were observed. The faecal examination using Baermann´s technique and fl otation was negative. Diagnosis was established following surgical removal of the worm. The specimen was determined as an A. vasorum female based on morphological features and confirmed by means of PCR technique and sequencing. To the best of our knowledge, the presented manifestation is the first ocular case of angiostrongylosis with absence of typical symptoms or signs 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.

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.

Survey-based pilot study into the chosen therapy and prophylaxis used by UK primary care veterinary surgeons against canine angiostrongylosis

Canine Angiostrongylosis (CA), a gastropod-borne parasitic infection caused by the metastrongyloid nematode Angiostrongylus vasorum, is an important cause of significant morbidity to domestic dogs across the UK as well as in other European countries. This study aimed to ascertain the frequency at which particular drugs were used by primary care practitioners in the UK for therapy against and prophylaxis for CA. Primary care veterinary clinicians were surveyed using an online questionnaire and face-to-face or telephone interviews. Eighty-six veterinary surgeons responded. The majority of practices (n = 52) included lungworm in their standard anthelmintic protocols; moxidectin was the most common drug used for prophylaxis (n = 71). Fenbendazole was the most frequently selected drug, by 45% of vets, for treatment of confirmed cases of CA despite it being unlicensed for this purpose in the UK and the absence of a clear treatment protocol. The results of this pilot study provide an initial insight into the approach taken by primary care practitioners in their approach to CA. This provides an important starting point for future studies investigating the decision-making for CA amongst UK veterinary surgeons, particularly to clarify whether in a larger cohort an unlicensed drug remains the treatment of choice. The absence of a clear protocol for fenbendazole means that treatment of dogs affected by CA may be suboptimal, increasing the risk of morbidity and mortality.

Genetic diversity and population structure of Angiostrongylus vasorum parasites within and between local urban foxes (Vulpes Vulpes)

Angiostrongylus vasorum is a nematode parasite of the pulmonary arteries and heart that infects domestic and wild canids. Dogs (Canis familiaris) and red foxes (Vulpes vulpes) are the most commonly affected definitive hosts. Recent studies suggest that angiostrongylosis is an emerging disease, and that red foxes may play an important role in the epidemiology of the parasite. Genetic analyses of parasites collected from dogs and foxes throughout Europe have shown that the same parasite haplotypes are commonly shared between different host species. However, the extent of genetic diversity within local A. vasorum populations and individual hosts is unknown. The objective of the present study was to assess the occurrence of genetic diversity among A. vasorum (a) recovered from different foxes within the Greater London area (a localised population, single worm per fox dataset); and (b) hosted within single foxes (multiple worms per fox dataset). During 2016, A. vasorum worms were collected from foxes culled for other purposes in London. DNA was extracted from each parasite and a partial fragment of the mitochondrial cytochrome oxidase subunit 1 (mtCOI) gene was amplified and sequenced. Sequences from the single worm dataset were compared with those published elsewhere. Combined, 19 haplotypes were described of which 15 were identified from foxes found in London, indicating that considerable genetic diversity can be detected within a local geographic area. Analysis of the multiple worm dataset identified 22 haplotypes defining worms recovered from just six foxes, emphasising the relevance of wild canines as reservoirs of genetic diversity. This is the first study to explore the genetic complexity of individual fox-hosted A. vasorum populations.

Respiratory and Cardiopulmonary Nematode Species of Foxes and Jackals in Serbia

As part of routine monitoring of foxes (Vulpes vulpes) and jackals (Canis aureus) on the territory of Vojvodina province (northern Serbia), an analysis of respiratory and cardiopulmonary parasitic nematodes was conducted. Both host species harbored Eucoleus aerophilus, E. boehmi and Crenosoma vulpis, whereas Angiostrongylus vasorum was found only in foxes. A high prevalence of infection (72.6 %) was noted for E. aerophilus in foxes. The remaining parasite species occurred less frequently in both host species. In all species where it could be quantified, a high degree of parasite aggregation within host individuals was noted. Single species infections were most common, whereas two and three species infections occurred less frequently in both host species. The distribution of abundance of E. aerophilus was affected by host sex, with abundances higher in male foxes. Sampling site and year influenced abundance variation in E. boehmi.

Angiostrongylus vasorum and Aelurostrongylus abstrusus: Neglected and underestimated parasites in South America

The gastropod-borne nematodes Angiostrongylus vasorum and Aelurostrongylus abstrusus are global causes of cardio/pulmonary diseases in dogs and cats. In the last decade, the number of reports on canine and feline lungworms has increased in several areas of Europe and North America. The unspecific clinical signs and prolonged course of these diseases often renders diagnosis challenging. Both infections are considered as emerging and underestimated causes of disease in domestic pets. In South America, little information is available on these diseases, apart from occasional reports proving the principle presence of A. vasorum and A. abstrusus. Thus, the purpose of this review is to summarize reports on infections in both domestic and wildlife animals in South America and to increase the awareness on gastropod-borne metastrongyloid parasites, which also include important zoonotic species, such as A. cantonensis and A. costaricensis. This review highlights the usefulness of diagnostic tools, such as the Baermann funnel technique, serology and PCR, and proposes to include these routinely on cases with clinical suspicion for lungworm infections. Future national epidemiological surveys are recommended to be conducted to gain a deeper insight into the actual epidemiological situation of gastropod-borne parasitoses in South America.

Faecal detection of the lungworms Crenosoma vulpis and Angiostrongylus vasorum and serological detection of A. vasorum in dogs from the Czech Republic

Dogs are definitive hosts for the lungworms Crenosoma vulpis and Angiostrongylus vasorum. Intermediate hosts are gasteropoda (Mollusca). In the past, lungworms in dogs were rarely identified in the Czech Republic and in neighbouring countries. A total of 253 dogs were sampled for faecal analysis performed by the Baermann method for isolation of first stage larvae (L1) of lungworms. A total of 193 serum samples were collected and analysed by ELISA for the detection of a circulating antigen and specific antibodies against A. vasorum. All dog owners were asked to fill out a questionnaire. Nine dogs (4.7%, 95% Confidence Interval, CI: 2.2–8.7%) were positive for the A. vasorum circulating antigen, seven dogs (3.6%, CI: 1.5–7.3%) had specific antibodies against A. vasorum; of these, three animals (1.6%, CI: 0.3–4.5%) were positive for both ELISAs. Most of them were under the age of three years. Only three of 13 seropositive dogs were not healthy, namely, in one dog vomitus was observed and two dogs were pyretic. Faecal samples of 5 dogs were positive for C. vulpis L1 (2.0%, CI: 0.6–4.6%). Angiostrongylus vasorum L1 were found in the faecal sample of one dog (0.4%, CI: 0.01–2.2%). This study illustrates the wide-spread occurrence of lungworms in the Czech Republic. Disease awareness of lungworms among animal owners and veterinarians should be implemented.

Canine angiostrongylosis in Sweden: a nationwide seroepidemiological survey by enzyme-linked immunosorbent assays and a summary of five-year diagnostic activity (2011-2015)

Background

For the first time in Sweden, Angiostrongylus vasorum was detected on the island of Sydkoster in foxes and dogs in 2003. After sporadic detection of the parasite in foxes in southern Sweden, the first positive canine faecal sample on the mainland was found in 2011. Since then a total of 2882 faecal samples have been analysed with the Baermann test at the National Veterinary Institute (SVA) during the years 2011–2015; 20 of them being positive. Contemporaneously, of over 525 fox necropsies, only three were found to be infected. To gather a more accurate knowledge of A. vasorum occurrence in Sweden, a large scale seroepidemiological survey was performed and totally 3885 serum samples from dogs were tested for both the presence of circulating antigens and of specific antibodies to A. vasorum.

Results

In total, 0.10% (n = 4, 95% Confidence Intervals, CI 0.03–0.26%) of the dogs were positive for both antigen and antibodies, whereas 0.51% (n = 20, CI 0.31–0.79%) of the tested dogs were only antigen positive and 0.88% (n = 34, CI 0.61–1.22%) only positive for specific antibodies. Seropositive animals, as well as the majority of A. vasorum-positive faecal samples tested during the same period, were spread over central and southern Sweden. Annual prevalence of positive faecal dog samples and of necropsied A. vasorum positive foxes (coming from southern Sweden) varied from 0.3 to 0.9% (overall: 0.7%, CI 0.4–1.1%) and 0.0 to 1.4% (overall: 0.3%, CI 0.1–0.9%), respectively.

Conclusions

The findings confirmed that A. vasorum has become established in various geographical areas of central and southern Sweden. Veterinarians and dog owners should be aware of the potential risks of infection in large areas of the country, since canine angiostrongylosis may be a fatal disease if left untreated.

Meerkats (Suricata suricatta), a new definitive host of the canid nematode Angiostrongylus vasorum

Angiostronglyus vasorum is a cardiopulmonary nematode infecting mainly canids such as dogs (Canis familiaris) and foxes (Vulpes vulpes). Natural infections have also been reported in mustelids and red pandas (Ailurus fulgens fulgens). We report the occurrence of natural A. vasorum infections in a group of captive meerkats (Suricata suricatta), housed at a university facility in Switzerland. A. vasorum first-stage larvae (L1) were initially identified in a pooled faecal sample. Individual samples, investigated with the Baermann-Wetzel technique, revealed that 41% (7/17) of the meerkats were infected, with ranges of 2–125 L1/g faeces. PCR and sequencing of part of the ITS-2 region resulted in 100% identity with A. vasorum. Infected animals did not show clinical signs. One meerkat died two days after diagnosis. Upon necropsy one adult specimen was recovered; histological examination of the lung revealed granulomatous pneumonia caused by A. vasorum larvae and eggs as well as intima and media hyperplasia and isolated arteriosclerosis of larger lung vessels. However, the cause of death was a spleen rupture with associated blood loss. All meerkats were topically treated with 10 mg imidacloprid/2.5 mg moxidectin per animal, after which they became negative in all follow up faecal examinations. Potential intermediate (gastropods) and paratenic hosts (birds) were collected from within or outside the meerkats enclosure. Gastropods were examined by PCR and bird samples by digestion. Four out of 193 (2.1%) gastropod samples were positive for A. vasorum, whereas none of the bird samples were positive. Meerkats, belonging to the Herpestidae, therefore are suitable definitive hosts for A. vasorum, with production and excretion of live L1. Meerkats kept in captivity in areas where A. vasorum is endemic and with potential contact to intermediate hosts are at risk of infection. Regular faecal examinations including Baermann-Wetzel technique should be considered.

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Meerkats are suitable definitive hosts for Angiostrongylus vasorum.

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This is the first case of A. vasorum in the Herpestidae family.

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A. vasorum larvae and eggs caused granulomatous pneumonia in an infected meerkat.

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2% of gastropods around the meerkats enclosure were positive for A. vasorum L3.

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Captive animal species in areas where A. vasorum is endemic are at risk of infection.

Repeated inoculations with the lung and heartworm nematode Angiostrongylus vasorum result in increasing larval excretion and worm burden in the red fox (Vulpes vulpes)

The French heartworm Angiostongylus vasorum is found in European red fox (Vulpes vulpes) and dog populations, where it appears to be spreading geographically. Once introduced into new areas, it establishes in local fox populations, typically to over 50% prevalence in a few years. High susceptibility and constant excretion of first stage larvae (L1) by the definitive hosts are prerequisites for sustaining high parasite biomass in a particular habitat. The present study explores the hypothesis that repeated ingestion of gastropods in nature will result in accumulation of adult worms and elevated excretion of L1 in feces. Experimentally infected foxes were subsequently inoculated via stomach tube once (9 weeks post initial inoculation) or twice (9 and 13 weeks post inoculation (wpi)) with 100 third stage A. vasorum larvae (L3) previously isolated from aquatic snails infected with L1 from a naturally infected dog. Despite large variation in fecal larval excretion for the individual animals within the groups, excretion of L1 was significantly higher in foxes twice inoculated as compared to foxes inoculated only once. With an outlier in the once inoculated group removed, excretion became significantly higher in the three times inoculated group. Establishment of adult worms varied and only a trend to higher worm burdens was found in the group of foxes inoculated three times. However, this became significant with the same single outlier removed. Overall, it appears that protective immunity to A. vasorum does not appear to occur in V. vulpes with animals exhibiting high infection intensities without obvious clinical signs. The increasing larval excretion in foxes being repeatedly exposed to A. vasorum L3 support the hypothesis that foxes under natural conditions may repeatedly ingest infected gastropods and remain a source of environmental contamination for several months, potentially contributing to the establishment of endemic foci through increasing L1 excretion.

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Foxes were experimentally infected with 100 Angiostrongylus vasorum larvae (L3).

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Two groups were later challenged once or twice.

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Increasing larval counts linked to time post infection and repeated inoculation.

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Data suggests role of foxes in rapid establishment of the parasite in new areas.

The effect of host age and inoculation dose on infection dynamics of Angiostrongylus vasorum in red foxes (Vulpes vulpes)

BACKGROUND

Infections and clinical cases of Angiostrongylus vasorum in dogs are found increasingly across Europe, thus rendering knowledge on its infection biology more important. We used red foxes as a carnivore model to examine the effect of host age and infection dose on the establishment of adult A. vasorum in single experimental infections.

METHODS

Fourteen juvenile and fourteen adult red foxes, free of metastrongyloid infections, were given a low (50) or high (200) dose of third-stage larvae (L3) of A. vasorum. Two groups of three foxes of each age group served as uninfected controls. Larval excretion by Baermann and blood parameters were followed for ten weeks. Worm counts were performed at necropsy by sequential perfusion, dissection and Baermann method.

RESULTS

The establishment rate (i.e. recovery in percentage of inoculation dose) of A. vasorum primary infections in red foxes was associated with host age and inoculation dose. In the low dose juveniles, 61% (range 52-72%) of the infection dose was recovered as worms in the pulmonary arteries and heart at necropsy while only 35% (21-50%) were recovered in the high dose. Corresponding establishment rates for adults were 39% (18-98%) and 8% (1-21%). In juveniles, a higher dose resulted in significantly higher adult worm counts, higher larval excretion and more pronounced pathophysiological changes, particularly in coagulation parameters. Earlier onset of patency was also found in the juveniles. In contrast, the larval excretion in high dose adults was very low and two infected animals never reached patency. However, a few adults showed only limited resistance as judged by excretion of larvae. The increase to very high larval excretion levels (> 4,000 larvae per g of faeces) after several months in a single animal, indicated that any potential acquired immunity does not affect worm fecundity.

CONCLUSIONS

Resistance to a primary A. vasorum infection was generally higher in older animals, and this age resistance was reflected in lower worm counts and reduced excretion of larvae. The juvenile red foxes were fully susceptible, as reflected in high establishment rates. Although severe clinical disease was never observed in the foxes, A. vasorum infections in red foxes appear to be chronic and moreover, to resemble infections in dogs. The results underline the red fox as a suitable model as well as natural reservoir for the parasite.

Performance of the Angio Detect™ in-clinic test kit for detection of Angiostrongylus vasorum infection in dog samples from Europe

Angiostrongylosis is a crucial differential diagnosis in any dog with respiratory, bleeding, neurological, or syncopal signs of unknown etiology in endemic areas. Many cases of angiostrongylosis have a fatal outcome; subclinical angiostrongylosis also has been reported. The most common method for supporting diagnosis of angiostrongylosis has been identification of Angiostrongylus vasorum first stage larvae in the feces by the Baermann-Wetzel method. Although considered as gold standard, this method has technical and sampling challenges and cannot detect infections during prepatency or in case of intermittent shedding of the larvae. A rapid in-clinic antigen test has been developed for serologic detection of A. vasorum infections using blood samples (Angio Detect™, IDEXX Laboratories Inc., Westbrook, Maine, USA). The study reported here was conducted to determine diagnostic sensitivity and specificity of the Angio Detect test kit by comparing Angio Detect testing results using serum or plasma samples with the results of Baermann-Wetzel testing using matched fecal samples. Samples from 214 dogs [with clinically suspected (N=195) or diagnosed angiostrongylosis (N=19)] were used for this evaluation. Baermann-Wetzel testing was performed independently at commercial reference laboratories or at university hospitals. All serum/plasma samples were blinded and randomized before testing with Angio Detect. The Angio Detect test was positive for 34 of the 35 cases found positive by the Baermann-Wetzel method; sensitivity of the Angio Detect test was 97.1% (95%CI: 85.1%-99.9%). The Angio Detect test was negative for 177 of 179 samples that were negative by the Baermann-Wetzel test; specificity was 98.9% (95%CI: 96.0%-99.9%). In cross-reactivity testing, all 89 samples from dogs confirmed to be infected with other common nematodes (Dirofilaria immitis, D. repens, Crenosoma vulpis, hookworms, ascarids, or whipworms) were all negative for A. vasorum by the Angio Detect antigen test. Angio Detect provides a rapid and reliable method for diagnosis of A. vasorum in clinically suspected dogs at risk for infection. The test requires minimal steps by the operator and provides results in 15min, allowing the clinician to initiate treatment for positive dogs before leaving the clinic.

Monthly administrations of milbemycin oxime plus afoxolaner chewable tablets to prevent Angiostrongylus vasorum infection in dogs

Background

Infection of dogs with the cardiopulmonary nematode Angiostrongylus vasorum may result in severe clinical disease therefore adequate prevention is necessary. A randomized, negative control, blinded study was conducted to evaluate the efficacy in the prevention of canine A. vasorum infection after monthly administrations of NexGard Spectra®, a novel chewable tablet formulation combining the insecticide and acaricide afoxolaner and the anthelmintic milbemycin oxime, in a multiple challenge (trickle infection) model.

Methods

Twenty beagle dogs were challenged orally with doses of approximately 32–43 third-stage larvae of A. vasorum once every other week on seven occasions (Study Days -7, 7, 21, 35, 49, 63 and 77). Ten dogs were administered NexGard Spectra® as close as possible to the minimum recommended dose of afoxolaner and milbemycin oxime, i.e. 2.5 mg/kg body weight and 0.5 mg/kg body weight, respectively, four times at monthly intervals (Study Days 0, 28, 56 and 84) while the remaining ten dogs served as untreated controls. For parasite recovery and count, dogs were euthanized humanely and necropsied six to eight days following the last treatment (Study Days 90–92). Beginning six weeks after first inoculation, faeces were collected on a bi-weekly basis and examined for first-stage larvae of A. vasorum.

Results

Untreated dogs harboured 39–95 adult A. vasorum (geometric mean, 66.4), while zero to 24 adult A. vasorum were recovered from the treated dogs (geometric mean, 3.4; P < 0.0001). Thus, efficacy of NexGard Spectra® administered at monthly intervals against incoming A. vasorum was 94.9 %. Compared to the untreated controls, larval excretion of the treated dogs was reduced by 99.9 % (P < 0.0001).

Conclusion

Results of this study demonstrate that NexGard Spectra®, when administered at monthly intervals, can effectively prevent canine A. vasorum infection.

Angiostrongylus vasorum Causing Severe Granulomatous Hepatitis with Concurrent Multiple Acquired PSS

A 14 mo old female Jack Russell terrier presented with a 12 hr history of vomiting and inappetence. She was subsequently diagnosed with multiple acquired portosystemic shunts during an exploratory celiotomy. Gross and histopathological hepatic abnormalities were consistent with chronic disease, including features suggestive of portal hypertension that was potentially caused by migrating and resident Angiostrongylus vasorum larvae. Fecal analysis and polymerase chain reaction of hepatic tissue confirmed the presence of Angiostrongylus vasorum . The dog recovered clinically following empirical treatment and supportive care. A lack of parasite burden was confirmed 9 wk postdiagnosis; however, serum biochemical analysis at that time was suggestive of ongoing hepatic dysfunction.

The development of Angiostrongylus vasorum (Baillet, 1866) in the freshwater snail Pomacea canaliculata (Lamarck, 1822)

Angiostrongylus vasorum is a parasitic nematode that infects the heart and pulmonary artery and its branches of domestic and wild canids. The parasite can use several species of terrestrial and aquatic molluscs as intermediate hosts, although susceptibility varies. Pomacea canaliculata is a mollusc found in lakes, swamps and rivers in South America. In this study, we evaluated the susceptibility, parasite growth, oviposition and larval development of 282 P. canaliculata infected with 500 A. vasorum first-instar larvae (L1). From day 5 post-infection (pi) to day 30 pi, seven specimens per day were sacrificed to recover the larval instars. We compared 50 egg masses from infected and uninfected molluscs to determine the number of eggs per clutch, the hatching rate and the growth of the molluscs. The percentage of recovered larvae ranged from 39.17% to 67.5%. First-stage larvae (L1) were found until day 19 pi, second-stage larvae (L2) were found from days 11 to 25 pi, and third-stage larvae (L3) were recovered only after day 19 pi. Infected snails exhibited the most eggs during spawning, although the rate of hatching and shell size were lower in the infected snails compared with controls. This is the first report of an experimental infection of P. canaliculata with A. vasorum, and the results confirm the non-specificity of the nematode in relation to the intermediate host and indicate the importance of epidemiological surveys of this parasite and mollusc.

A post-mortem study of respiratory disease in small mustelids in south-west England

Background

Stoat (Mustela erminea) and weasel (Mustela nivalis) populations in south-west England are declining whilst polecats (Mustela putorius), absent for over a century, are increasing. Little is known about the health status of these species nationally. This study aimed at investigating respiratory disease in specimens found dead in south-west England.

Results

Trauma caused by road traffic, predator attack or being trapped was the predominant cause of death in 42 stoats, 31 weasels and 20 polecats; most were in good physical condition. Skrjabingylus nasicola was present in all species (weasels 37 %, polecats 39 %, stoats 41 %) and infected animals showed no evidence of loss of body condition. Even in carcases stored frozen L₁ larvae were frequently alive and highly motile. Angiostrongylus vasorum infection was diagnosed in two stoats and one weasel: in stoats infections were patent and the lung lesions were likely of clinical significance. These are believed to be the first records of A. vasorum in small mustelids. Pleuritis and pyothorax was seen in two polecats, in one case due to a migrating grass awn. Histological examination of lungs showed granulomata in stoats (38 %), weasels (52 %) and polecats (50 %). Spherules consistent with Emmonsia spp. adiaspores were present in the granulomata of stoats (60 %), weasels (36 %) and polecats (29 %). Adiaspore diameter in all three species was similar (means: stoats 39 μm, weasels 30 μm, polecats 36 μm); these are markedly smaller than that normally recorded for E. crescens. Although they lie within the accepted range for spores of Emmonsia parva this arid-zone species is not found in Britain, thus raising a question over the identity of the fungus. Cases showing numerous granulomata but few or no adiaspores were Ziehl-Neelsen-stain negative for acid-fast bacilli and IHC negative for Mycobacterium spp. However, in some cases PCR analyses revealed mycobacteria, including Mycobacterium kumamotonense and Mycobacterium avium Complex. One stoat had numerous unidentified small organisms present centrally within granulomata.

Conclusions

Stoats, weasels and polecats in south-west England share several respiratory diseases, often of high prevalence, but the pathology would appear insufficient to impact on the health status of the populations and other ultimate causes of death should be investigated when examining these species.

Angiostrongylus vasorum in the eye: new case reports and a review of the literature

Background

Nematodes of the genus Angiostrongylus are important causes of potentially life-threatening diseases in several animal species and humans. Angiostrongylus vasorum affects the right ventricle of the heart and the pulmonary arteries in dogs, red foxes and other carnivores. The diagnosis of canine angiostrongylosis may be challenging due to the wide spectrum of clinical signs. Ocular manifestations have been seldom reported but have serious implications for patients.

Methods

The clinical history of three cases of infection with A. vasorum in dogs diagnosed in UK, France and Italy, was obtained from clinical records provided by the veterinary surgeons along with information on the diagnostic procedures and treatment. Nematodes collected from the eyes of infected dogs were morphologically identified to the species level and molecularly analysed by the amplification of the nuclear 18S rRNA gene.

Results

On admission, the dogs were presented with various degrees of ocular discomfort and hyphema because of the presence of a motile object in the eye. The three patients had ocular surgery during which nematodes were removed and subsequently morphologically and molecularly identified as two adult males and one female of A. vasorum.

Conclusions

Three new cases of canine ocular angiostrongylosis are reported along with a review of other published clinical cases to improve the diagnosis and provide clinical recommendation for this parasitic condition. In addition, the significance of migratory patterns of larvae inside the host body is discussed. Veterinary healthcare workers should include canine angiostrongylosis in the differential diagnosis of ocular diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1440-6) contains supplementary material, which is available to authorized users.

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.

Combined Serological Detection of Circulating Angiostrongylus vasorum Antigen and Parasite-specific Antibodies in Dogs from Hungary

The occurrence of the nematode Angiostrongylus vasorum, also known as the French heartworm, is increasingly being reported from various European countries. The adults of this parasite species live in the pulmonary arteries and right cardiac ventricle of wild canids and domestic dogs. Larval stages and eggs in the lungs induce inflammatory verminous pneumonia, causing severe respiratory disease in dogs. Furthermore, haematological and neurological signs and even death may occur. In Hungary, A. vasorum has been identified in red foxes, golden jackals and in two dogs and some slugs. In this first large-scale survey, 1247 sera from pet dogs were collected and tested by an ELISA for the detection of circulating antigen of A. vasorum and by a separate ELISA to detect specific antibodies against the parasite. A total of 1.36% (n = 17, 95 % confidence intervals, CI: 0.80 - 2.17 %) of the animals were positive in both ELISAs, while 1.76 % (n = 22, CI: 1.11 - 2.66 %) of the tested dogs were antigen-positive only and 2.73 % (n = 34, CI: 1.90 - 3.79 %) were positive for specific antibodies only. Regions with antigen- and antibody-positive animals overlapped and were distributed over nearly the whole sampled areas of the country. A considerable number of cases was observed in Budapest and also in the southern part of the country bordering Croatia, while in the most eastern part bordering Ukraine no positive samples were detected. These results confirm the endemic occurrence of A. vasorum in dogs originating from different parts of Hungary and the significant advantages of A. vasorum serology in epidemiological studies.

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.

The first report of Angiostrongylus vasorum (Nematoda; Metastrongyloidea) in Poland, in red foxes (Vulpes vulpes)

Angiostrongylus vasorum belongs to the superfamily of Metastrongyloidea. This nematode occurs in foxes, dogs and other predators. The Nematode A. vasorum place themselves in the pulmonary artery and its branches, and in the right ventricle and atrium of the heart. Numerous species of land snails are the intermediate hosts of the parasite. In 2013, lungs and hearts of 76 foxes shot in the Forest District Głęboki Bród in Augustowska Primeval Forest were parasitologically necropsied. Four of the examined foxes were infected with the nematode A. vasorum, a prevalence of 5.2%. In one fox pericardium there were 6 male and 6 female nematodes. In the remaining three foxes nematodes were localized in the pulmonary artery. In two foxes 2 specimens of nematodes were detected (male and female, and two females) while 1 female was detected in the other fox. This is the first report of the presence of the nematode A. vasorum in fox in Poland.

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.

Moving the boundaries to the South-East: first record of autochthonous Angiostrongylus vasorum infection in a dog in Vojvodina province, northern Serbia

Background

Angiostrongylus vasorum is a cardiopulmonary canine nematode, potentially fatal to its host. In the last decade, there has been an increasing number of autochthonous cases in areas previously considered non-endemic. However, information about the parasite’s occurrence and distribution among Central and Eastern (Southeastern) European countries are scarce. This paper reports the first recorded case of autochthonous A. vasorum infection in a hunting dog from Serbia.

Findings

In March 2013, a female hunting dog was presented to a veterinary clinic in Novi Sad, Serbia, for examination of a chronic skin problem. The dog had no history of respiratory or cardiovascular diseases. Faecal and urine samples were collected and examined for the presence of parasite ova/cysts. A modified Baermann test detected 8.8 larvae per gram of faeces. Based on their overall body length (mean 381.7 ± 15.9 μm; range from 342.5 to 404.3 μm; n = 12) and characteristic tail morphology, they were identified as the first-stage larvae of A. vasorum.

Conclusions

The spread of A. vasorum to the southeast of Europe is further confirmed after finding autochthonous infected dog from Serbia. Therefore, veterinary professionals in Serbia should consider A. vasorum in differential diagnosis of dogs.

First report of Angiostrongylus vasorum and Hepatozoon from a red fox (Vulpes vulpes) from West Virginia, USA

Angiostrongylus vasorum was identified in the lungs of a red fox (Vulpes vulpes) from West Virginia, United States (US), indicating a new geographical location for this metastrongylid nematode. The fox was euthanized and submitted for necropsy after displaying erratic behavior. We did not detect rabies virus or canine distemper virus from the fox. We observed bronchopneumonia associated with A. vasorum infection disseminated in both lungs. In addition, protozoal meronts were observed in the liver, spleen, and mesenteric lymph node, and were identified as Hepatozoon canis. Lymphoid depletion was also observed in the spleen and mesenteric lymph node. In addition to A. vasorum and H. canis infections, Eucoleus aerophilus eggs and adult worms were observed in the lungs of the fox. Severe lesions associated with A. vasorum infection were observed in the lungs and these were determined to be the likely cause of morbidity; however, synergistic effects among the multiple infections detected in this fox cannot be ruled out. This is the first report of an autochthonous A. vasorum infection in the US and from outside of Newfoundland Canada, the only place in North America where the parasite is known to be endemic. Additionally, this is the first report of a H. canis infection in a red fox from the US.

Insights into the immuno-molecular biology of Angiostrongylus vasorum through transcriptomics--prospects for new interventions

Angiostrongylus vasorum is a metastrongyloid nematode of dogs and other canids of major clinical importance in many countries. In order to gain first insights into the molecular biology of this worm, we conducted the first large-scale exploration of its transcriptome, and predicted essential molecules linked to metabolic and biological processes as well as host immune responses. We also predicted and prioritized drug targets and drug candidates. Following Illumina sequencing (RNA-seq), 52.3 million sequence reads representing adult A. vasorum were assembled and annotated. The assembly yielded 20,033 contigs, which encoded proteins with 11,505 homologues in Caenorhabditis elegans, and additional 2252 homologues in various other parasitic helminths for which curated data sets were publicly available. Functional annotation was achieved for 11,752 (58.6%) proteins predicted for A. vasorum, including peptidases (4.5%) and peptidase inhibitors (1.6%), protein kinases (1.7%), G protein-coupled receptors (GPCRs) (1.5%) and phosphatases (1.2%). Contigs encoding excretory/secretory and immuno-modulatory proteins represented some of the most highly transcribed molecules, and encoded enzymes that digest haemoglobin were conserved between A. vasorum and other blood-feeding nematodes. Using an essentiality-based approach, drug targets, including neurotransmitter receptors, an important chemosensory ion channel and cysteine proteinase-3 were predicted in A. vasorum, as were associated small molecular inhibitors/activators. Future transcriptomic analyses of all developmental stages of A. vasorum should facilitate deep explorations of the molecular biology of this important parasitic nematode and support the sequencing of its genome. These advances will provide a foundation for exploring immuno-molecular aspects of angiostrongylosis and have the potential to underpin the discovery of new methods of intervention.

Geographical, clinical, clinicopathological and radiographic features of canine angiostrongylosis in Irish dogs: a retrospective study

Background

Angiostrongylus vasorum infection is associated with high morbidity and mortality in dogs. Although recognised in Ireland, there are no large series of cases reported. The aim of this retrospective study was to identify pertinent clinical and geographical features in Irish dogs.

Results

The case records of dogs presenting to the University College Dublin Veterinary Hospital (1999-2010) were reviewed. A contemporaneous review of external faecal parasitology and post mortem submissions was also performed. A positive diagnosis of angiostrogylosis was identified in 49 dogs including 24 clinical, 10 post mortem and 15 external faecal sample cases. The majority (n = 44 (90%)) resided on the East Coast.

In the clinical cases, the median age was 20 months, 29% of cases were older than 2 years. Clinical features included cardiorespiratory (63%), coagulopathic (71%) and other (63%) signs. Cough (n = 10), dyspnoea (n = 5) and tachypnoea (n = 3) were the most common cardiorespiratory abnormalities. Of animals with evidence of coagulopathy, excessive haemorrhage from a wound (n = 5), airway haemorrhage (n = 9), epistaxis (n = 3), haematoma (n = 4), suspected haemarthrosis (n = 3), neurological signs (n = 2) and haematuria (n = 1) were found. Ten dogs were anaemic, of which two were severe (haematocrit ≤ 0.20 L/L). Ten animals had thrombocytopenia, with four severely affected (≤50 × 10⁹/L). PT and APTT values were prolonged in 4 (24%) of 17 and a BMBT was prolonged in 5 (63%) of 8 cases. Vague signs of exercise intolerance (n = 6), lethargy (n = 6) and weakness (n = 2) were identified, with two (8%) animals having only these signs. In one animal the diagnosis appeared to be incidental. Thoracic radiographs (n = 19) identified abnormalities in 100% of cases. Four (17%) animals died before or within 24 hours of treatment and post mortem examinations confirmed angiostrongylosis. Fenbendazole was administered in 19 cases, 18 (95%) recovered. Two animals were euthanised, one which failed to respond to therapy and another in which an ante mortem diagnosis had not been made.

Conclusions

Angiostrongylosis is not uncommon in Ireland, is not confined to young dogs or the East Coast and can present with a wide variety of signs, particularly coagulopathic, respiratory or neurological signs.

Imaging diagnosis: CT findings in a dog with intracranial hemorrhage secondary to angiostrongylosis

A seven-month-old Cocker Spaniel had a cough, acute lethargy, decreased responsiveness, and episodes of hyperexcitability. There were bilateral generalized increased lung sounds, bilateral episcleral hemorrhage, and systemic hypertension. Prolonged buccal mucosal bleeding time and elevated D-dimer concentrations were detected. Radiographically, there was a generalized moderate unstructured interstitial pattern. In thoracic CT images, there was a diffuse moderate hyperattenuating appearance of the bronchial walls and interstitium and diffuse areas of moderate bronchiectasis. The brain CT images were characterized by marked hyperattenuating well-defined masses. In addition, there were smaller hyperattenuating and hypoattenuating masses scattered throughout the cerebral and cerebellar parenchyma. A zinc sulphate flotation test confirmed large numbers of Angiostrongylus vasorum L1 larvae. Despite therapy the dog continued to deteriorate and underwent euthanasia. Postmortem examination confirmed the presence of multiple intracranial and extracranial hemorrhages. Angiostrongylosis should be considered as one of the differential diagnoses in dogs presenting with neurologic signs consistent with acute intracranial haemorrhage.

Effect of temperature on activity of third-stage larvae of Angiostrongylus vasorum

To evaluate the effect of temperature on the activity and mortality of the L3 of Angiostrongylus vasorum, 1,500 L3 were isolated from experimentally infected snails and distributed into five equal groups. Three groups were incubated at 37°C, 27°C, and 5°C. The remaining two groups were incubated at 27°C and 5°C for 10 days, at which time the temperature for the 27°C group was reduced to 5°C and the 5°C group increased to 27°C. Larva activity was observed daily and inactive larvae were removed. At 37°C, larvae survived up to 8 days. At 27°C, larvae were active until day 6. When subjected to a reduction in temperature from 27°C to 5°C beginning on day 10, the number of active larvae increased until day 13. Only on day 17 did the number of active larvae decline to zero. At 5°C, larvae remained active until day 15, surviving to 24 days. When temperature was increased from 5°C to 27°C beginning on day 10, larvae were found active until day 12 and maintained an intermediate level of activity to day 21. Survival of larvae was greater at lower temperatures, while high temperatures were associated with higher mortality.

Autochtonous infection of dogs and slugs with Angiostrongylus vasorum in Hungary

On the course of a helminthological survey of the dogs of Baranya County, Hungary Angiostrongylus vasorum infection was detected in two asymptomatic dogs. Identification of the parasite was based on morphology of the first-stage larvae (L1) isolated from droppings, and successful experimental infection with first stage larvae to laboratory reared Discus rotundatus and Lissachatina fulica snails, in order to exclude species of the family Filaroididae that have similar larvae to A. vasorum. While angiostrongylosis is widespread among foxes, this is the first report of A. vasorum infection in housedog in Hungary. In gardens, where infected dogs were being kept 91 specimens of 6 species of limacid and arionid slugs were collected of which 5 specimens of Arion lusitanicus were found to carry larvae of A. vasorum. Dogs usually do not ingest such large slugs willingly. Frogs are known to act as paratenic hosts in the life cycle of A. vasorum. Since one of the infected dogs harboured also infection with the intestinal trematode Alaria alata, of which frogs certainly play the role of the second intermediate host, therefore it is assumed that in this case the dog became infected with A. vasorum by eating frogs.