The first clinically manifested case of angiostrongylosis in a dog in Slovakia

Comprehensive Map of Canine Angiostrongylosis in Dogs in Spain

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

Hemostatic Dysfunction in Dogs Naturally Infected with Angiostrongylus vasorum—A Narrative Review

This narrative review aims to describe Angiostrongylus vasorum-induced hemostatic dysfunction of dogs with emphasis on clinical and laboratory findings as well as potential therapeutic strategies for the bleeding patient. Canine angiostrongylosis (CA) is a disease with potentially high morbidity and mortality in endemic areas and with fatal outcome often associated with either severe respiratory compromise, pulmonary hypertension and right-sided heart failure, or hemostatic dysfunction with severe bleeding. The most common signs of hemorrhage are hematomas, petecchiation, ecchymoses, oral mucosal membrane bleeding and scleral bleeding, while intracranial and pulmonary hemorrhage are among the most severe. The pathophysiological mechanisms underlying hemostatic dysfunction in these patients are presently researched. While the larval effect on platelets remains unknown, the parasite appears to induce dysregulation of hemostatic proteins, with studies suggesting a mixture of pro-coagulant protein consumption and hyperfibrinolysis. Importantly, not all dogs display the same hemostatic abnormalities. Consequently, characterizing the hemostatic state of the individual patient is necessary, but has proven difficult with traditional coagulation tests. Global viscoelastic testing shows promise, but has limited availability in general practice. Treatment of A. vasorum-infected dogs with hemostatic dysfunction relies on anthelmintic treatment as well as therapy directed at the individual dog’s specific hemostatic alterations.

Serological and faecal detection of Angiostrongylus vasorum in dogs from Austria

Canine angiostrongylosis is a potentially lethal parasitic disease that can manifest itself with a broad spectrum of clinical signs, including respiratory distress, neurological and bleeding disorders, or non-specific signs. The occurrence of Angiostrongylus vasorum is widely reported in Europe, but very little is known about its presence in Austria. In this first large-scale survey, 1279 sera were collected from Austrian dogs and tested by an ELISA for the detection of circulating antigen of A. vasorum (sensitivity: 95.7%, specificity 94.0%) and by a separate ELISA detecting specific antibodies (sensitivity 81.0%, specificity 98.8%). Furthermore, 1040 faecal samples were tested for the presence of lungworm first stage larvae (L1). One dog (0.1%, 95% confidence intervals [CI]: 0.0-0.4%) was positive in both ELISAs, while 1.2% (n = 15, CI: 0.7-1.9%) of the tested dogs were antigen-positive and 1.5% (n = 19, CI: 0.9-2.3%) were positive for specific antibodies. Overall, 13 dogs (1.3%; CI: 0.7-2.1%) were positive for A. vasorum L1 while 31 dogs were positive for Crenosoma vulpis L1 (3.0%; CI: 2.0-4.2%). One dog shed L1 from both A. vasorum and C. vulpis (0.1%, CI: 0.0-0.5%). Dogs positive for A. vasorum originated from northeast, southeast and south Austria (antigen and/or antibody detection), but also from north, west and southwest Austria (antibody detection) and from northeast and west Austria (L1 detection). One of 88 blood samples (1.1%, CI: 0.0-6.2%) submitted from the eastern part of Austria was positive by a rapid assay for A. vasorum antigen detection (Angio Detect™). Crenosoma vulpis positive samples originated from northwest, north, northeast, south and west Austria. These results confirm the very sporadic occurrence of A. vasorum in the investigated areas of the country. However, due to the substantial infectious pressure from the surrounding countries and the free circulation of dogs and foxes acting as wildlife reservoirs and due to clinical relevance for infected dogs, it is crucial to maintain disease awareness also in areas where the parasite has not yet been detected.

Highly Variable Clinical Pictures in Dogs Naturally Infected with Angiostrongylus vasorum

Canine angiostrongylosis by Angiostrongylus vasorum is increasingly reported in both enzootic and previously free areas. The complex pathogenesis of the disease makes the clinical workup challenging. Infected dogs show highly variable clinical pictures, characterized by subclinical to life-threatening general, cardio-respiratory, neurological and/or gastrointestinal signs. The present study reports the high variability of clinical pictures from 36 dogs across central and southern Italy that were naturally infected by A. vasorum. Of them, 23 (63.9%) presented at least one clinical sign, while 13 (36.1%) were subclinically infected and apparently healthy. Overall, 19 dogs (52.8%) showed cardiorespiratory signs, 14 (38.9%) had non-specific abnormalities, 2 (5.6%) presented coagulation disorders and 1 (2.8%) had a severe neurological condition. Importantly, four dogs presenting with clinical signs had neither cough nor dyspnea. These results underline that angiostrongylosis should be included in the differential diagnosis, even when dogs display only non-specific clinical signs. The proportion of apparently healthy dogs highlights the relevance of routine copromicroscopic and/or antigenic tests in enzootic areas to avoid the sudden onset of potentially life-threatening signs.

Dirofilaria spp. and Angiostrongylus vasorum: Current Risk of Spreading in Central and Northern Europe

In the past few decades, the relevance of Dirofilaria immitis and Dirofilaria repens, causing cardiopulmonary and subcutaneous dirofilariosis in dogs and cats, and of Angiostrongylus vasorum, causing canine angiostrongylosis, has steadily increased in Central and Northern Europe. In this review, a summary of published articles and additional reports dealing with imported or autochthonous cases of these parasites is provided for Central (Austria, Czechia, Germany, Hungary, Luxemburg, Poland, Slovakia, Slovenia, and Switzerland) and Northern (Denmark, Finland, Iceland, Norway, and Sweden) Europe. Research efforts focusing on Dirofilaria spp. and A. vasorum have varied by country, and cross-border studies are few. The housing conditions of dogs, pet movements, the spread of competent vectors, and climate change are important factors in the spread of these nematodes. Dogs kept outside overnight are a major factor for the establishment of Dirofilaria spp. However, the establishment of invasive, diurnal, synanthropic, competent mosquito vectors such as Aedes albopictus may also influence the establishment of Dirofilaria spp. The drivers of the spread of A. vasorum remain not fully understood, but it seems to be influenced by habitats shared with wild canids, dog relocation, and possibly climatic changes; its pattern of spreading appears to be similar in different countries. Both Dirofilaria spp. and A. vasorum merit further monitoring and research focus in Europe.

Simultaneous Exposure to Angiostrongylus vasorum and Vector-Borne Pathogens in Dogs from Italy

Several drivers have recently fostered the expansion of Angiostrongylus vasorum throughout Europe, where Vector-Borne Pathogens (VBPs) are also spreading. However, the level of simultaneous risk of infection is still unknown in canine populations. This study evaluated the simultaneous exposure to A. vasorum and major canine VBPs in dogs of Italy. Sera of 294 dogs were subjected to two ELISAs, detecting A. vasorum circulating antigens and antibodies against the parasite, and to the following assays: (i) SNAP® 4DX (IDEXX Laboratories Inc.) detecting Dirofilaria immitis antigens, and antibodies vs. Borrelia burgdorferi, Anaplasma spp. and Ehrlichia spp. and (ii) IFAT for the detection of antibodies vs. Leishmania infantum, Babesia canis and Rickettsia conorii. Twenty-two (7.5%, CI: 4.8-11.1%) and six (2%, CI: 0.7-4.4%) dogs scored positive for circulating A. vasorum antibodies and antigens, respectively. Seventeen dogs (5.8%, CI: 3.4-9.1%) were positive for A. vasorum antibodies + at least one VBP, three (1%, CI: 0.2-3%) for A. vasorum antigen + at least one VBP, while one dog (0.3%, CI: 0.01-1.88%) was positive for A. vasorum antigen + A. vasorum antibodies + B. canis antibodies. These results show that dogs living in different regions of Italy are at risk of simultaneous infections with both A. vasorum and VBPs. Despite the same scenario being likely in other countries of Europe, the current knowledge is scant. Therefore, further studies are warranted to amplify current epizootiological information and to understand whether control programs should be improved.

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.

GIS-based environmental analysis of fox and canine lungworm distribution: an epidemiological study of Angiostrongylus vasorum and Crenosoma vulpis in red foxes from Slovakia

Over a period of intervening years, the distribution of two canine cardiopulmonary metastrongylid nematodes, Angiostrongylus vasorum and Crenosoma vulpis, has been recognised in Central Europe. Here, we report the first epidemiological research conducted in red foxes from Slovakia and the potential influence of selected environmental variables on the parasites' occurrence, quantified by logistic regression. The environmental models revealed that distribution of C. vulpis is not significantly influenced by any environmental variables, and the parasite is present in the whole area under study. Models for A. vasorum revealed some weak influence of environmental variables, as it tends to occur in drier areas with lower proportion of forest. Moreover, A. vasorum shows a typical spatial clustering and occurs in endemic foci identified mainly in the eastern part of Slovakia. A cluster of A. vasorum infection foci was also found in the north-eastern region, where the average winter air temperature regularly falls below - 10 °C.

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.

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.

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

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

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.