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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., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Angiostrongylus vasorum is a highly pathogenic metastrongylid nematode affecting dogs, which uses gastropod molluscs as intermediate hosts. The geographical distribution of the parasite appears to be heterogeneous or patchy and understanding of the factors underlying this heterogeneity is limited. In this study, we compared the species of gastropod present and the prevalence of A. vasorum along a rural-urban gradient in two cities in the south-west United Kingdom., Methods: The study was conducted in Swansea in south Wales (a known endemic hotspot for A. vasorum) and Bristol in south-west England (where reported cases are rare). In each location, slugs were sampled from nine sites across three broad habitat types (urban, suburban and rural). A total of 180 slugs were collected in Swansea in autumn 2012 and 338 in Bristol in summer 2014. A 10 mg sample of foot tissue was tested for the presence of A. vasorum by amplification of the second internal transcribed spacer (ITS-2) using a previously validated real-time PCR assay., Results: There was a significant difference in the prevalence of A. vasorum in slugs between cities: 29.4% in Swansea and 0.3% in Bristol. In Swansea, prevalence was higher in suburban than in rural and urban areas. Comparing the sampled slug fauna, Arion rufus was found in greater numbers in Swansea than Bristol, and was commonly infected (prevalence 41%). This, alongside the timing of slug collections in summer rather than autumn, could explain low infection prevalence in the Bristol sample. In the absence of Ar. rufus as a preferred host for A. vasorum, Ar. flagellus and Limacus maculatus appear to act as versatile hosts that are present in suburban and urban areas in Swansea (prevalence in Ar. flagellus 33%; in L. maculatus 44%) and in Bristol (prevalence in Ar. flagellus 0.9%). These slug species might provide A. vasorum with an alternative vehicle to reach the final host, when the main host Ar. rufus is scarce or absent., Conclusion: We conclude that the composition of the slug fauna varies spatially, and that this could help explain patchiness in the prevalence of A. vasorum. A suburban peak was found in the prevalence of infection in intermediate hosts, perhaps explained by a higher density of competent intermediate and/or definitive hosts.

The nematode Angiostrongylus vasorum is becoming more widely recorded globally, and is of increasing concern as a cause of disease in dogs. Apparent geographic spread is difficult to confirm due to a lack of standardized disease recording systems, increasing awareness among veterinary clinicians, and recent improvements in diagnostic technologies. This study examines the hypothesis that A. vasorum has spread in recent years by repeating the methods of a previous survey of the fox population. The hearts and lungs of 442 foxes from across Great Britain were collected and examined by dissection and flushing of the pulmonary circulation and microscopic inspection of tracheal scrapes. Sampling and parasite extraction methods were identical to an earlier survey in 2005 to ensure comparability. Prevalence of A. vasorum was 18·3% (exact binomial confidence bounds 14·9-22·3), compared with 7·3% previously (5·3-9·9, n = 546), and had increased significantly in most regions, e.g. 7·4% in the Northern UK (previously zero) and 50·8% in the south-east (previously 23·2%). Other nematodes identified were Crenosoma vulpis (prevalence 10·8%, CI 8·1-14·2) and Eucoleus aerophilus (31·6%, CI 27·3-36·2). These data support the proposal that A. vasorum has increased in prevalence and has spread geographically in Great Britain.

The nematode parasite Angiostrongylus vasorum is an increasingly important cause of respiratory and other diseases in dogs. Geographical spread from previously limited endemic foci has occurred rapidly. This paper investigates parasite epidemiology around the location of the first reported case in Scotland in 2009: by detection of A vasorum-specific DNA in gastropod intermediate hosts, and in dogs circulating DNA and specific antibodies, and first stage larvae in faeces. Overall prevalence in gastropods was 6.7 per cent (16/240), with parasite DNA found in slugs in the Arion ater and Arion hortensis species aggregates and the snail Helix aspersa (syn. Cornu aspersum). Of 60 dogs presenting with clinical signs compatible with angiostrongylosis, none tested positive using PCR on peripheral blood or Baermann test on faeces, and none of 35 tested for circulating anti-A vasorum antibodies were positive. PCR prevalence in gastropods was highest (11 per cent) in the park frequented by the canine angiostrongylosis index case. Molecular survey for infection in gastropods is a potentially informative and efficient method for characterising the distribution of A vasorum and therefore local risk of canine infection. However, there appears to be a complex relationship between prevalence in gastropods and emergence of canine clinical disease, which requires further work to advance understanding of parasite transmission and geographical disease spread., (British Veterinary Association.)

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.

Dogs infected with Angiostrongylus vasorum, a potentially lethal parasite parasitizing the heart and pulmonary arteries, may present severe respiratory, haematological and neurological signs. In this first large-scale seroepidemiological survey, 4003 sera originating from Germany and 4030 from the UK were tested by an ELISA for the detection of circulating antigen of A. vasorum, and by a separate ELISA detecting specific antibodies. In Germany, where mainly western federal states were sampled, 0·3% (n = 13, CI: 0·2–0·6%) of dogs were positive in both ELISAs, whereas in total 0·5% (n = 20, CI: 0·3–0·8%) were antigen-positive and 2·25% (n = 90, CI: 1·8–2·8%) were positive for specific antibodies. Regions with antigen- and antibody-positive animals were overlapping. In the UK, where mainly the south of the country was sampled, 0·97% (n = 39, CI: 0·7–1·3%) of dogs were antigen- and antibody positive. In total, 1·32% (n = 53, CI: 1·0–1·7%) were antigen-positive, and 3·2% (n = 129, CI: 2·7–3·8%) were positive for specific antibodies, again in overlapping regions. These results confirm the occurrence of A. vasorum in a random dog population originating from large parts of the countries investigated. The use of the tests alone or in combination was considered as a function of their sensitivities and specificities, in order to guide efficient clinical and epidemiological application.

This study reports the development of a real-time PCR assay and an indirect ELISA to improve on current detection of canine Angiostrongylus vasorum infection. A highly specific fluorescent probe-based, real-time PCR assay was developed to target the A. vasorum second internal transcribed spacer region and detected DNA in EDTA blood, lung tissue, broncho-alveolar larvage fluid, endotracheal mucus, pharyngeal swabs and faecal samples. PCR was fast (∼1 h), highly efficient when using EDTA blood samples, consistently detected a single molecule of parasite DNA and did not amplify DNA from other parasitic nematodes or definitive host species. An indirect ELISA was also developed using the soluble protein fraction from adult A. vasorum worms. Some cross-reactive antigen recognition was observed when tested against sera from dogs infected with Crenosoma vulpis (n = 8), Toxocara canis (n = 5) and Dirofilaria immitis (n = 5). This was largely overcome by setting the cut-off for a positive result at an appropriately high level. Field evaluation of the real-time PCR and ELISA was conducted by testing sera and EDTA blood from dogs with suspected A. vasorum infection (n = 148) and compared with the Baermann's larval migration test in faeces. Thirty-one dogs were positive by at least one test. Of these, 20 (65%) were detected by the Baermann method, 18 (58%) by blood PCR, 24 (77%) by ELISA and 28 (90%) by blood PCR and ELISA together. Combined testing using real-time PCR and ELISA therefore improved the detection rate of A. vasorum infection and holds promise for improved clinical diagnosis and epidemiological investigation.

Angiostrongylus vasorum is an emerging parasite of dogs and related carnivores throughout western Europe and presents a biosecurity threat to many countries worldwide. Infections are difficult to diagnose due to a high variability of clinical signs and can be fatal if left untreated. Previous attempts to develop indirect ELISA as a diagnostic test for antibody presence in dogs have been limited by cross-reactive recognition of antibodies to other endemic nematodes. This study compared the immuno-dominant soluble somatic proteins for first stage, third stage and adult A. vasorum using Western blotting. 2D electrophoresis and mass spectrometry were further used to identify specific immuno-dominant proteins (n=14) within the soluble fraction from whole adult worms. Proteins included an aspartyl protease inhibitor, representing a potential candidate for a recombinant-based ELISA and novel vaccine., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Infection with the nematode Angiostrongylus vasorum is an emerging cause of canine disease in Europe and part of North America, yet published data on its epidemiology in endemic areas are lacking. This study tested faecal samples from 897 dogs attending veterinary practices in the southern part of Great Britain, a long standing endemic focus. Among 790 dogs presenting with respiratory or other signs broadly suggestive of angiostrongylosis, 16% tested positive on a single Baermann's examination, compared with 2% of healthy dogs in the same catchment areas. Risk factors for positive tests included age (higher risk in younger dogs), season (more cases earlier in the calendar year), and worming history (lower risk if given milbemycin oxime in the past 12 weeks). Sex, neutering status and breed were not significant in terms of risk of testing positive. The most common clinical signs in infected dogs were respiratory, along with non-specific signs such as lethargy and exercise intolerance, while bleeding, neurological and gastrointestinal signs were also recorded. Around half the dogs sampled that showed signs of extra-pulmonary disease also had respiratory signs. Direct faecal smears and Baermann's tests read after one hour detected 56% and 83% of diagnosed cases respectively. The data confirm that A. vasorum is commonly associated with disease in endemic areas, which manifests with a broad range of signs at primary care level. Information on risk factors is useful in diagnosis and control, and forms a basis for further epidemiological investigation., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Angiostrongylus vasorum is an emerging parasite that is currently distributed through Western Europe and parts of South America. An isolated population is also present in Newfoundland, Canada. This presents a risk of onward spread into North America, but its origin is unknown. To ascertain the phylogeographic relationships and genetic diversity of A. vasorum within the western Palaearctic and eastern Nearctic ecozones, a total of 143 adult and larval nematode specimens were collected from foxes (Vulpes vulpes) and dogs (Canis lupus familiaris) in Canada, Denmark, France, Germany, Ireland, the Netherlands, Portugal and the United Kingdom, and a coyote (Canis latrans) in Canada. DNA was extracted and the second internal transcribed spacer and two mitochondrial loci were amplified and sequenced. Multiple haplotypes (n=35) based on combined mitochondrial sequences (1078bp) of the partial cytochrome oxidase subunit I (COI), large subunit ribosomal RNA (rrnL) and the complete nicotinamide adenine dinucleotide dehydrogenase 3 (NADH3) sequences, were observed throughout the Palaearctic countries sampled; however, only a single haplotype was observed for the Canadian A. vasorum population. The likely origin of A. vasorum in Newfoundland is therefore inferred to be within the western Palaearctic. There was no evidence of genetic segregation of parasites in dogs, foxes and coyotes, supporting the hypothesis that transmission occurs between wild and domestic canids. The transmission dynamics and population structure of this nematode are further discussed., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

Objective: The aim of this article is to review Angiostrongylus vasorum infection in dogs, including the life cycle, signalment, clinical signs, diagnosis, and treatment. Apparent changes in the epidemiology of this unique parasite are considered, alongside information available regarding its recent geographic spread., Etiology: A. vasorum is a metastrongyloid parasite capable of causing an array of clinical problems in dogs, including cardiorespiratory, coagulopathic, and neurologic signs. Currently, the parasite has a worldwide distribution; however, it usually arises in small pockets of enzootic foci. Recent reports suggest a changing distribution of this parasite, which has renewed interest in its epidemiology and in the risk of expansion to new areas including mainland North America., Diagnosis: A definitive diagnosis of angiostrongylosis is usually made using the modified Baermann technique either using feces or tracheobronchial secretions; however, this review also discusses novel methods such as serologic and molecular techniques., Therapy: Once a diagnosis of angiostrongylosis is made, prompt treatment should follow with anthelmintic drugs (such as moxidectin/imidacloprid, milbemycin oxime, or fenbendazole) and supportive care dependent upon the patient's clinical signs. Currently, there is no proven prophylactic regime., Prognosis: The prognosis appears to be very dependent upon the severity of clinical signs at presentation. A. vasorum can be fatal and death may be sudden. However, if a prompt diagnosis is made and appropriate treatment is administered complete clinical resolution is possible.

The parasitic nematode Angiostrongylus vasorum is an emerging challenge for companion animal and wildlife health, with reported increases in both distribution and incidence in Europe. To facilitate improved detection of this parasite, a SYBR green real-time polymerase chain reaction (PCR) was developed to amplify a region of the second internal transcribed spacer (ITS-2) of A. vasorum from both definitive and intermediate host samples. The PCR assay was capable of detecting a single of plasmid DNA containing the entire ITS-2 region, a single first stage larva (L1) in 200 microl canine EDTA blood, a single L1 in 200 mg of canine faeces and a single L3 in 10mg of Biomphalaria glabrata tissue. The assay exhibited a high level of specificity to A. vasorum and whilst it potentially amplifies DNA of other Angiostrongylus species, it did not amplify DNA from a range of other common canine parasitic nematodes. Field evaluation of the PCR assay was conducted by screening canine EDTA blood and faecal samples from suspected cases of A. vasorum infection and compared with Baermann's detection, and also by screening a range of gastropod species from an endemic area. Real-time quantitative PCR offers a more efficient means of detecting A. vasorum infection with a lower limit of detection than traditional diagnostic tests, and it therefore has important clinical and epidemiological applications.

The geographic range of Angiostrongylus vasorum is expanding, leading to increased disease. Although observed cases of canine pulmonary angiostrongylosis have been dutifully reported in the literature, the state of biological knowledge remains too poor to predict future patterns of spread with any confidence. Nevertheless, there is an urgent need to identify areas that are likely to be suitable for parasite establishment. Preliminary attempts to do this using a climatic envelope approach suggest that several new areas are open to colonisation, even without invoking climate change. The risk of parasite importation into these areas should be mitigated, e.g. by restricting movement of dogs unless tested or treated for A. vasorum, and monitored by focused surveillance of definitive and intermediate hosts. These efforts will benefit from newly developed diagnostic tests.

A 9-year-old, male, captive red panda (Ailurus fulgens fulgens) in an urban zoo in the United Kingdom presented with respiratory distress and weight loss. The animal was euthanatized, and a postmortem examination was performed. The lungs were diffusely consolidated with extensive mineralization. Microscopically, there was extensive obliteration of normal pulmonary architecture by sheets and coalescing nodules of partially mineralized fibrous tissue and granulomatous inflammation centered on large numbers of nematode larvae and eggs. First stage nematode larvae were isolated from lung tissue and were characterized as Angiostrongylus vasorum on the basis of their morphology and sequencing of the 18S ribosomal RNA gene and the entire second internal transcribed spacer. Although A. vasorum has previously been reported in red pandas in a zoological collection in Denmark, this study is the first reported case in the United Kingdom and occurs against a background of geographical spread and increased incidence of disease in domestic and wild canids. Angiostrongylus vasorum should be considered a differential diagnosis for respiratory disease in the red panda and taken into account when planning parasite and pest control programs for zoological collections.

Angiostrongylus vasorum is a nematode parasite of sylvan and domestic species of the family Canidae. It has a broad but patchy distribution worldwide, and there is evidence for geographical spread and increasing incidence of infection in recent years. While historically Angiostrongylus-like nematodes identified in dogs and foxes have been described as A. vasorum in Europe and Angiocaulus raillieti in South America, more recent taxonomic revision has amalgamated these into a single species, A. vasorum. Here we report, for the first time, the molecular characterization of isolates of A. vasorum from Germany, Portugal, Denmark and the United Kingdom on the basis of the mitochondrial COI gene and the second ribosomal internal transcribed spacer. When compared with isolates from Brazil, sequence analysis revealed 2 distinct genotypes. Estimated rates of evolution based on COI sequences for both nematode and host are consistent with the hypothesis that the presence of A. vasorum in South America is a result of an ancient evolutionary event. Angiostrongylus vasorum in South America potentially represents a separate species to that observed in Europe.

Recent reports suggest that the canine heartworm Angiostrongylus vasorum is expanding from traditional endemic foci in several parts of the world. We are ill placed to judge the causes and potential consequences of this expansion because of a lack of knowledge about fundamental aspects of the biology of the parasite. We call for a renewed focus on this important but neglected nematode.