Efficacy of Bravecto® Plus spot-on solution for cats (280 mg/ml fluralaner and 14 mg/ml moxidectin) in the prevention of feline Aelurostrongylus abstrusus infection evaluated in a multi-diagnostic approach

BACKGROUND

Aelurostrongylus abstrusus is one of the most important respiratory nematodes of felines. Infections may lead to respiratory clinical signs with varying severity or even death, emphasizing the need for preventive treatment of cats with outdoor access to circumvent patent infections.

METHODS

Therefore, the preventive efficacy of a spot-on formulation of 280 mg/ml fluralaner and 14 mg/ml moxidectin (Bravecto® Plus spot-on solution for cats, MSD) against A. abstrusus was evaluated in a negative controlled, randomized and partially blinded efficacy study with 28 purpose-bred cats in a non-terminal design. In three different treatment regimes, the minimum recommended dose of 40 mg fluralaner and 2.0 mg moxidectin/kg bodyweight (BW) was administered once at 12, 8 or 4 weeks (study group G1, G2 and G3, respectively) prior to experimental infection with 300 third-stage A. abstrusus larvae, while G4 served as placebo-treated control.

RESULTS

From 30 to 46 days post infection (dpi; SD 114 to 130), faeces were sampled to monitor first-stage larvae (L1) excretion for efficacy determination. Secondary efficacy criteria, including respiratory parameters, serological antibody levels and computed tomography (CT) findings, were assessed once before enrolment (SD -7 to -1) and before infection (SD 75 to 83). After infection, CT evaluation was performed once at 47-50 dpi (SD 131 to 134), and respiratory parameters and antibody levels were regularly assessed twice or once a week, respectively (1 up to 78 dpi, SD 85 up to 162). All animals in the control group excreted L1 by 33-37 dpi and remained positive throughout the study period from 41 to 46 dpi (SD 125 to 130). In the treatment groups, only one animal each of G1 and G2 excreted L1 at two consecutive days, and four cats of G1, two of G2 and three of G3 were positive on single occasions. While the geometric mean (GM) of the maximum number of excreted L1 per 5 g of faeces was 7380.89 in the control group (G4), GMs were significantly lower in the treatment groups with 1.63 in G1, 1.37 in G2 and 0.79 in G3. Thus, based on GMs, the reduction in excreted L1 exceeded 99.9% in all three treatment groups. Based on CT severity scores, all lungs of the animals of the control group showed severe pulmonary changes post infection, whereas lungs of the cats of the treatment groups were either unaltered (4 animals), mildly (11 animals), or moderately altered (5 animals). Moreover, seroconversion was observed in all cats of the control group, but not in those of the treatment groups.

CONCLUSIONS

The combination of diagnostic methods used in this non-terminal study yielded coherent and reliable results. A single administration of Bravecto® Plus spot-on solution for cats was well tolerated and effective in the prevention of aelurostrongylosis for at least 12 weeks.

First report of apparent praziquantel resistance in Dipylidium caninum in Europe

Dipylidium caninum is a common tapeworm of dogs. Two cases of praziquantel resistance have been described in D. caninum in the United States. No further reports have been published to the authors’ knowledge. Here, the case of a dog imported to Switzerland from Spain with a history of chronic excretion of tapeworm proglottids and unresponsiveness to praziquantel treatments is reported. Clinical signs were mild (restlessness, tenesmus, anal pruritus, squashy feces) and flea infestation could be ruled out. Infection with D. caninum was confirmed through morphological and genetic parasite identification. Different subsequently applied anthelmintic compounds and protocols, including epsiprantel, did not confer the desired effects. Proglottid shedding only stopped after oral mebendazole administration of 86.2 mg kg−1 body weight for 5 consecutive days. Clinical signs resolved and the dog remained coproscopically negative during a follow-up period of 10 months after the last treatment. This case represents the first reported apparent praziquantel and epsiprantel resistance in D. caninum in Europe. Treatment was extremely challenging especially due to the limited availability of efficacious alternative compounds.

Intraocular Parafilaria bovicola infection and surgical removal in a mixed breed heifer

An approximately 1.5-year-old mixed breed heifer was presented for evaluation and treatment due to ocular pain affecting the right eye secondary to a live nematode within the anterior chamber. Ophthalmic examination revealed marked blepharospasm, evidence of chronic keratitis, uveitis, and a single, white, approximately 2.5 cm long, 0.5 mm thick, living parasite. The heifer underwent general anesthesia, and the parasite was removed using passive aqueous humor outflow following a stab incision into the anterior chamber. Twenty-four hours after removal of the intraocular parasite, the heifer displayed a significant improvement in ocular comfort, corneal edema, and uveitis. The nematode was identified via genetic analyses as Parafilaria bovicola, a filarial parasite of cattle. The heifer was discharged 5 days following nematode removal with a marked improvement in all ocular signs and apparently normal vision. To the authors' knowledge, there are no previous reports of confirmed intraocular filariosis caused by P. bovicola in the veterinary literature, nor are there reports detailing surgical removal of intraocular parasites in bovids.

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

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

Case report: Infection with Dicrocoelium dendriticum in a Japanese Chin dog

Dicrocoelium dendriticum is a trematode colonising the bile ducts of herbivores. Coproscopic findings in dogs are usually considered gastrointestinal passages of eggs after ingestion of unheated liver tissue or infected ruminant faeces. Here, a Japanese Chin presented with diarrhoea and weight loss. Eggs comparable to D. dendriticum were detected in faeces and infection was confirmed via PCR and by ruling out differential diagnoses. Egg excretion continued for a period of 10 months. Praziquantel (50 mg/kg body weight [BW]) was administered orally for four consecutive days. Egg excretion 10 days after treatment entailed further treatments with 100 mg/kg BW, again for four days. Faecal samples were negative ten days and four weeks afterwards, diarrhoea resolved, and the dog gained weight. In cases of repeated coproscopic positivity for D. dendriticum, an infection with dogs acting as definitive hosts should be considered. Treatment with praziquantel at a higher dosage may be required.

Dynamics of protozoal excretion in the faeces of calves during the first 28 days after arrival at the fattening farm indicate infection before regrouping and show poor temporal correlation with diarrhoea

BACKGROUND

Calves in dairy cattle production in Switzerland are transported to a fattening farm at the age of 3-5 weeks, and frequently suffer from diarrhoea within the first 14 days after arrival. To characterise the role of intestinal protozoa in this, we investigated the excretion dynamics of Eimeria, Cryptosporidium and Giardia during the first 28 days after the arrival and regrouping of calves at fattening farms.

METHODS

A total of 610 faecal samples from 122 calves (mean age 37.3 days; mean body weight 79.8 kg) were collected on seven different fattening farms during the first 28 days after the arrival and regrouping of the animals. The farms were visited between January and April (cold season; n = 4) and between June and August (warm season; n = 3). The samples were collected rectally on days 1, 4, 7, 14 and 28, assessed for consistency, and analysed using the McMaster method for quantitative determination of the number of Eimeria oocysts per gram of faeces (OPG), flotation for morphological differentiation of the unsporulated Eimeria oocysts, a concentration method for the semi-quantitative determination of Giardia cysts, and modified Ziehl-Neelsen staining for semi-quantitative determination of Cryptosporidium oocysts.

RESULTS

Overall, 50.8% (62/122) of the animals had diarrhoea during the study period. However, the faecal excretion of protozoal pathogens was neither associated with diarrhoea nor with body weight gain of the animals. Altogether, 90.2% (110/122) of the calves were Eimeria positive. Eimeria zuernii was excreted by 51 (41.8%) and Eimeria bovis by 68 (55.7%) animals. In the warm season more animals tested positive for Eimeria and OPGs were higher than in the cold season. There was no correlation between the age of the calves and the OPG values. Overall, 64.8% (79/122) of the calves excreted Eimeria oocysts within the first 7 days, indicating that they had been infected with the parasite on the dairy farm of origin. Eighty-nine calves (73.0%) excreted Giardia cysts, with more positive animals in the cold (80.3%) compared with the warm season (64.3%). Only Giardia duodenalis assemblage E was identified. Cryptosporidium oocysts were microscopically detected in 14 animals (11.5%) on five farms. Cryptosporidium spp. were present in a total of 12 animals, i.e. Cryptosporidium parvum in nine, Cryptosporidium ryanae in two, and Cryptosporidium bovis in one animal.

CONCLUSIONS

A better understanding of the temporal dynamics of protozoal infections in calves is helpful for the implementation of appropriate measures to protect the health of these animals at a critical phase in their lives. Our results indicate that factors other than those examined in the present study contributed to the onset of diarrhoea in the calves.

Strongyle faecal egg counts in Swiss horses: A retrospective analysis after the introduction of a selective treatment strategy

The standard parasite management of horses based on regular anthelmintic treatments, now practiced for decades has resulted in a worrying expansion of resistant helminth populations, which may considerably impair control on the farm level. The aim of the present study was to obtain a retrospective (year 2010 - 2016) nationwide analysis of faecal egg count (FEC) data from the Swiss adult horse population, related to horse age and geographic region. Thirteen labs provided a total of 16,387 FEC data of horses aged four to 39 years (average: 13.6 years). The annual number of performed FEC tests increased from 38 to 4,939 within the observation period. Independent of the annual sample size the yearly patterns of the FEC were very similar. Seventy-eight percent (n = 12,840) of the samples were negative and 90 % (n = 14,720) showed a FEC below 200 strongyle eggs per gram (EPG) of faeces. The annual mean strongyle FEC ranged between 60 and 88 EPG with a total mean of 75 EPG. Horses aged 4-7 years showed a significantly (p < 0.00001) higher mean FEC compared with the other age groups, differences were not significant among the older horses. Based on ZIP codes, samples were allocated by 70.0 %, 6.0 % and 0.2 % to the German-, French- and Italian-speaking regions of Switzerland, respectively. With 222 EPG the mean FEC in the French part of Switzerland was significantly higher (p < 0.05) than in the German-speaking region (60 EPG). Eggs of Parascaris spp., anoplocephalids and Strongyloides westeri were found in 0.36 %, 0.32 % and 0.01 % of the samples, respectively. Based on 3,813 questionnaire feedbacks from owners in 2017 covering a total of 12,689 horses, sixty-eight percent (n = 8,476) were dewormed without diagnosis, two percent (n = 240) were not dewormed at all, whereas for 30 % (n = 3,721) the selective anthelmintic treatment (SAT) concept was applied. The SAT implementation rate differed significantly (p < 0.0005) between regions, with 33 %, 20 % and 25 % for the German-, French- and Italian-speaking areas, respectively. The rate of horses spending 16-24 h on pasture per day was significantly higher in the French-speaking region compared to the German-speaking part of Switzerland (p < 0.0001). In addition, pasture hygiene was practiced at a significantly lower rate in the French-speaking part compared to the German- and Italian-speaking regions (both p < 0.0001). Overall, the shift towards the SAT-concept represents a very promising development with respect to mitigating the further spread of anthelmintic resistance.

Diagnostic challenges for Aelurostrongylus abstrusus infection in cats from endemic areas in Italy

BACKGROUND

The lungworm Aelurostrongylus abstrusus infects wild and domestic feline species worldwide and is considered a primary respiratory parasite of cats. Definitive diagnosis is based on the identification of first-stage larvae (L1s) released in faeces approximately 5 to 6 weeks after infection. More recently, serology has been shown to be a diagnostic alternative for A. abstrusus infection in cats. The present study aimed at evaluating the diagnostic performance of serological antibody detection compared to faecal examination for A. abstrusus infection in a population of cats with known infection status from endemic areas in Italy and to identify factors (larval scores, age, co-infections with other helminths) that may influence test sensitivity and specificity of serology.

METHODS

All cats resulting positive using the Baermann technique (n = 78) were tested with the A. abstrusus ELISA. An additional 90 serum samples from cats living in three geographical areas with infection prevalence > 10%, but that resulted negative on Baermann, were also tested.

RESULTS

Among 78 cats copromicroscopically positive for L1s of A. abstrusus (Group 1), 29 (37.2%) were seropositive in ELISA. Of the 90 cats from Group 2 (cats living in three geographical areas in Italy with A. abstrusus prevalence > than 10%, but negative on Baermann examination), 11 (12.2%) were positive on ELISA. The overall seroprevalence was 23.8%. There was no statistical difference either between average optical density (OD) values of cats excreting > 100 L1s vs. cats excreting < 100 L1s (0.84 vs. 0.66; P value = 0.3247) or comparing the OD values with age of infected cats. Few Baermann-negative cats positive for Toxocara cati or hookworms were seropositive, supporting lack of cross-reactivity to these nematodes.

CONCLUSIONS

Results from the present study suggest that relying solely on faecal examination may underestimate prevalence of A. abstrusus infection in cats and that field surveys based on antibody detection are useful for establishing true prevalence of infected and/or exposed animals.

A pilot study for the isolation of Eimeria spp. oocysts from environmental straw samples in comparison with individual faecal examination of fattening calves

The diagnosis of eimeriosis in calves mainly relies on the presence of diarrhoea and the excretion of Eimeria oocysts in the faeces. Restraining the animals to collect rectal samples for diagnostic purposes is stressful and time-consuming. The aim of this study was to evaluate a method for the quantification of oocysts in environmental barn straw samples. To investigate the recovery rate of the method, straw and Eimeria negative faeces were spiked with Eimeria oocysts in plastic bags and mixed with water and 0.05% Tween 20 (v/v); the liquids were filtered twice through sieves (mesh size 300 and 52 μm), centrifuged and the number of oocysts in the sediment determined using a McMaster counting chamber. A recovery rate of 52.4% (95% confidence interval: 48.2-56.5%) was obtained. In the following, field straw (n = 156) and individual faecal samples (n = 195, also analysed by McMaster counting chambers) were collected on four different farms. Eimeria oocysts were present on all farms in faecal (84/195, 43.1%) and straw samples (119/156, 76.3%). In 37 (23.7%) straw samples, sporulated oocysts were observed, with a sporulation rate ranging from 0 to 40%. Despite high variability between farms and examination days, mean numbers of oocysts in the straw positively correlated with mean numbers of oocysts excreted in the faeces (ρ_Spearman = 0.60). The examination of environmental straw samples may represent an easy-to-perform, non-invasive, inexpensive preliminary diagnostic approach for surveillance of eimeriosis at group level, having the potential to assess the infection pressure.

Helminths and their management in Swiss Army horses: differences between riding horses and pack horses evidence the need of improvement

INTRODUCTION

Intestinal helminth management in horses has both clinical and epidemiologic relevance, in additional association with anthelmintic resistance. The Swiss Army employs military owned riding horses and privately owned pack horses, which are brought together for service periods up to 12 weeks. We compared husbandry conditions and intestinal helminth management of both groups via questionnaire and analysed faecal samples of 53 riding horses and 130 pack horses using combined sedimentation/flotation, the McMaster method and larval cultures. Riding horses only had cyathostomin infections (prevalence: 60,4 %), while pack horses harboured cyathostomins (71,5 %), Parascaris sp. (6,9 %) and Strongylus vulgaris (1,5 %). Regression models combining faecal sample results with questionnaire data unveiled correlations of husbandry practices with parasite frequencies identifying risk and protective factors. Pasture management, hygiene and deworming practices were highly variable for pack horses, while for riding horses there was an overall concept. This included a selective deworming strategy with faecal egg counts (FECs) of strongyles prior to deworming, applying a threshold of 200 eggs per gram of faeces (epg). Anthelmintic treatments based on FECs, weekly faeces removal on pastures (pastures), the use of macrocyclic lactones and deworming horses regularly were identified as protective factors regarding the 200 epg threshold for strongyle eggs. Accordingly, the mean epg for strongyle eggs between the groups (111 and 539 in riding and pack horses, respectively) was significantly different (p < 0,001). Overall, intestinal helminth management in pack -horses showed room for improvement regarding pasture hygiene, the used anthelmintics and the frequency of deworming, from which all Swiss Army horses would benefit, as they share pastures during their -service, therefore entailing the risk of parasite transmission.

Strongyloides stercoralis in Swiss dogs - a retrospective study suggests an increasing occurrence of this potentially zoonotic parasite as a consequence of dog imports

INTRODUCTION

Strongyloides stercoralis is a worldwide occurring nematode infecting canids and primates (including humans), responsible for a largely underestimated zoonotic disease. We here present 18 cases including overall 20 dogs affected by S. stercoralis, diagnosed in Switzerland between 2010 and 2020. The Baermann examination was positive for S. stercoralis larvae in 10, suspicious in 4, negative in one and not performed in 2 dogs. In 3 dogs the infection was identified only at necropsy by histology or by direct faecal or mucosal smears from intestinal tissue. Confirmation of suspected, necropsied and Baermann-negative dogs relied on genetic analyses. Twelve dogs had a history of import from Eastern Europe (n=4), the Mediterranean basin (n=5) or Germany (n=3). They were 7 weeks to 9,5 months old, and also the dogs supposedly born in Switzerland were younger than one year (except two, aged 15 months and 14 years). Thirteen dogs were males and 6 females (1 unknown). The most represented breeds were Chihuahuas (n=5), French Bulldogs (n=4) and Pomeranians (n=3). The most frequent clinical sign and reason for presentation was diarrhoea, occurring in 11/20 animals. Further gastrointestinal symptoms were vomiting, anorexia/hyporexia, adipsia, dehydration, tense abdomen and tenesmus. Respiratory symptoms were the second most frequent, with coughing in 7/20 animals, followed by tachypnoea/dyspnoea in 5 and (reverse) sneezing in 3 dogs. Treatment with 50 mg/kg BW fenbendazole p.o. over 5 days was successful in 4 cases in which a follow-up examination was performed 3-6 weeks later; prolonged treatment over 21 days was also effective. Ivermectin off-label protocols described in the literature, e.g. 0,8 mg/kg BW s.c. or 0,5 mg/kg BW i.m. repeated after 2 weeks, were successful based on control examinations performed 3-10 weeks later. Strongyloides stercoralis infections are clinically relevant, potentially zoonotic and need to be included in differential diagnoses in case of canine gastrointestinal and respiratory disorders, especially in young and imported dogs.

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.

The Angiostrongylus vasorum Excretory/Secretory and Surface Proteome Contains Putative Modulators of the Host Coagulation

Angiostrongylus vasorum is a cardiopulmonary nematode of canids and is, among others, associated with bleeding disorders in dogs. The pathogenesis of such coagulopathies remains unclear. A deep proteomic characterization of sex specific A. vasorum excretory/secretory proteins (ESP) and of cuticular surface proteins was performed, and the effect of ESP on host coagulation and fibrinolysis was evaluated in vitro. Proteins were quantified by liquid chromatography coupled to mass spectrometry and functionally characterized through gene ontology and pathway enrichment analysis. In total, 1069 ESP (944 from female and 959 from male specimens) and 1195 surface proteins (705 and 1135, respectively) were identified. Among these were putative modulators of host coagulation, e.g., von Willebrand factor type D domain protein orthologues as well as several proteases, including serine type proteases, protease inhibitors and proteasome subunits. The effect of ESP on dog coagulation and fibrinolysis was evaluated on canine endothelial cells and by rotational thromboelastometry (ROTEM). After stimulation with ESP, tissue factor and serpin E1 transcript expression increased. ROTEM revealed minimal interaction of ESP with dog blood and ESP did not influence the onset of fibrinolysis, leading to the conclusion that Angiostrongylus vasorum ESP and surface proteins are not solely responsible for bleeding in dogs and that the interaction with the host's vascular hemostasis is limited. It is likely that coagulopathies in A. vasorum infected dogs are the result of a multifactorial response of the host to this parasitic infection.

Fox Serum Proteomics Analysis Suggests Host-Specific Responses to Angiostrongylus vasorum Infection in Canids

Dogs infected with the cardiopulmonary nematode Angiostrongylus vasorum may suffer from respiratory distress and/or bleeding disorders. Descriptions of clinical signs in foxes are rare, despite high prevalence. To evaluate the impact of infection on coagulation and immune response, serum proteins from eight experimentally infected foxes before and after inoculation (day 0, 35, 84, 154) were subjected to differential proteomic analyses based on quantitative data and compared to available data from dogs. The number of proteins with differential abundance compared to the uninfected baseline increased with chronicity of infection. Bone marrow proteoglycan, chitinase 3-like protein 1 and pulmonary surfactant-associated protein B were among the most prominently increased proteins. The abundance of several proteins involved in coagulation was decreased. Enriched pathways obtained from both increased and decreased proteins included, among others, "platelet degranulation" and "haemostasis", and indicated both activation and suppression of coagulation. Qualitative comparison to dog data suggests some parallel serum proteomic alterations. The comparison, however, also indicates that foxes have a more adequate immunopathological response to A. vasorum infection compared to dogs, facilitating persistent infections in foxes. Our findings imply that foxes may be more tolerant to A. vasorum infection, as compared to dogs, reflecting a longer evolutionary host-parasite adaptation in foxes, which constitute a key wildlife reservoir.

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.

Aelurostrongylus abstrusus Antibody Seroprevalence Reveals That Cats Are at Risk of Infection throughout Germany

Cats infected with the metastrongylid nematode Aelurostrongylus abstrusus may show clinical signs ranging from mild to severe respiratory disease or remain unobserved, despite damages present in the lung tissue. This study aimed to determine the seroprevalence and distribution of A. abstrusus in cats by testing serum samples from all over Germany to identify potential risk areas and strengthen disease awareness accordingly. Sera of 2998 cats were screened for the presence of antibodies against A. abstrusus by ELISA, and the data were evaluated by a geographic information system to visualise the regional distribution of the analysed samples. Overall, 12.0% of the samples tested positive (361/2998 cats, 95% confidence interval: 10.9–13.3%). Seropositive cats were identified throughout the country, suggesting that all cats in Germany with outdoor access are at risk of A. abstrusus infection and that the infection is overall underdiagnosed. Increased testing for A. abstrusus infection would allow earlier detection of infected animals, hence improving the life quality and health of cats and preventing potential death under anaesthesia.

Spread of anthelmintic resistance in intestinal helminths of dogs and cats is currently less pronounced than in ruminants and horses - Yet it is of major concern

Anthelmintic resistance (AR) has thus far only rarely been reported for intestinal helminths of dogs and cats, in contrast to parasites of livestock and horses. We highlight possible reasons for this striking and important discrepancy, including ecological, biological and genetic factors and/or intervention regimens of key intestinal helminths concerning both host groups. In view of the current knowledge related to the genetics, mechanisms and principles of AR development, we point at issues which in our view contribute to a comparatively lower risk of AR development in intestinal helminths of dogs and cats. Finally, we specify research needs and provide recommendations by which, based on the available information about AR in ruminant and equine helminths, the development of AR in dog and cat helminths may best be documented, prevented or at least postponed.

Do All Roads Lead to Rome? The Potential of Different Approaches to Diagnose Aelurostrongylus abstrusus Infection in Cats

An infection with the cat lungworm, Aelurostrongylus abstrusus, can be subclinical, but it can also cause severe respiratory clinical signs. Larvae excretion, antibody levels, clinical assessment findings of the respiratory system and diagnostic imaging findings were recorded and compared for six cats with experimental aelurostrongylosis. In five cats, patency started 33-47 days post infection (pi), but two cats excreted larvae only in long intervals and low numbers. Positive ELISA results were observed in four cats with patent aelurostrongylosis, starting between five days before and 85 days after onset of patency. One seropositive cat remained copromicroscopically negative. Mild respiratory signs were observed in all cats examined. A computed tomographic (CT) examination of the lungs displayed distinct alterations, even in absence of evident clinical signs or when larvae excretion was low or negative. The thoracic radiograph evaluation correlated with the CT results, but CT was more distinctive. After anthelmintic treatment in the 25th week post infection, pulmonary imaging findings improved back to normal within 6-24 weeks. This study shows that a multifaceted approach, including diagnostic imaging, can provide a clearer diagnosis and monitoring of disease progression. Furthermore, a CT examination provides an alternative to post mortem examination and worm counts in anthelmintic efficacy studies.

Investigation of the occurrence of Angiostrongylus vasorum in coyotes in southern Ontario, Canada

In North America, the only endemic focus for Angiostrongylus vasorum (French heartworm) was historically thought to occur in the southeastern part of the island of Newfoundland. However, reports of A. vasorum infection in wild canids in West Virginia, USA, and Nova Scotia, Canada, suggest the introduction of the parasite to mainland North America. We screened for A. vasorum in coyotes from across southern Ontario. Additionally, we evaluated the performance of ELISAs for detection of circulating A. vasorum antigen (Ag-ELISA) and antibodies against A. vasorum (Ab-ELISA) designed for use in sera or blood of foxes for use with coyotes in this region. Autopsies were performed on 397 coyotes, and lung tissue extract prepared from each carcass was tested via both ELISAs. The sensitivity and specificity for both tests were estimated in the absence of a gold standard using a 2-test single population Bayesian model; sensitivity and specificity priors were based on the performance of the assays in foxes in Switzerland. Eight coyotes tested positive for A. vasorum antigen; no animal was antibody positive. The estimated sensitivity and specificity of the Ag-ELISA were 90.8% (95% credible interval [CrI]: 83.8–95.6%) and 95.5% (95% CrI: 93.4–97.2%), respectively. For the Ab-ELISA, the estimated sensitivity and specificity were 41.9% (95% CrI: 32.1–51.9%) and 98.0% (95% CrI: 96.3–99.0%), respectively. Based on these findings and negative postmortem data for the same animals, there is insufficient evidence to suggest the presence of A. vasorum in southern Ontario coyotes.

Serum amyloid A levels and alpha 2 and gamma globulins on serum protein electrophoresis in cats exposed to and infected with Leishmania infantum

Background

Dogs are the main reservoir hosts of Leishmania infantum; nevertheless, recent investigations indicate a likely role for cats in the epidemiology of Leishmania infection. Feline leishmaniosis (FeL) remains poorly characterised, partly due to the lack of suitable diagnostic tools. This study aimed to compare serum amyloid A (SAA) levels and serum protein electrophoresis (SPE) profiles (specifically, alpha 2 and gamma globulins) in cats naturally exposed to or infected by L. infantum from southern Italy versus those of healthy controls and versus cats with neoplastic or inflammatory conditions from non-endemic areas.

Methods

Serum or plasma samples from four cohorts of cats were analysed for SAA levels and by SPE: (i) G1: healthy controls from Leishmania-non-endemic regions of Switzerland; (ii) G2: cats pre-diagnosed with neoplastic or inflammatory conditions available from the University of Cambridge sample archive; (iii) G3: L. infantum-seropositive, quantitative (q)PCR-negative cats from southern Italy; (iv) G4: L. infantum-seropositive and qPCR-positive cats from southern Italy. SAA data were assessed for normality and homoscedasticity using the Shapiro–Wilk and Levene’s tests, respectively; the Kruskall–Wallis test, followed by Dunn’s test with Bonferroni correction were subsequently used to compare SAA serum levels between groups. A weighted generalised linear model with a binomial distribution was used to assess statistically significant differences in the numbers of animals displaying elevated gamma globulins and increased alpha 2 globulins between groups.

Results

Overall, 68 samples were analysed (G1: n = 16, G2: n = 20, G3: n = 20, G4: n = 12). Cats suffering from neoplastic and inflammatory conditions (G2 ) showed significantly higher SAA levels than healthy controls (G1) (median values [interquartile range]: G1: 0.00 [0.00–0.00] mg/l versus G2: 0.85 [0.00–49.55] mg/l). G2, G3 and G4 cats showed higher percentages of individuals with increased alpha 2 globulins (percentages ± standard error: G1 = 20.0% ± 10.3, G2 = 80.0% ± 8.9, G3 = 70.0% ± 10.2, G4 = 75.0% ± 12.5) and gamma globulins (G1 = 0.0% ± 0, G2 = 65.0% ± 10.7, G3 = 50.0% ± 11.2, G4 = 58.3% ± 14.2) than healthy control cats (G1). For all three markers, no significant difference between cats within G2, G3 and G4 was recorded.

Conclusions

This study indicates that the proportions of animals with elevated levels of alpha 2 and gamma globulins are significantly higher in cats exposed to and infected with L. infantum. Levels of SAA and alpha 2 and gamma globulins may not be used to differentiate between L. infantum infection or exposure, and neoplastic and/or inflammatory conditions.

Graphic Abstract

Lungworms (Metastrongylus spp.) and intestinal parasitic stages of two separated Swiss wild boar populations north and south of the Alps: Similar parasite spectrum with regional idiosyncrasies

Metastrongylus sp. is a lungworm with worldwide distribution in wild boars and other suids. In Switzerland, two wild boar populations are geographically divided by the Alps. We investigated 84 wild boars, 52 from north and 32 from south of the Alps, different in sex and age (juveniles, subadults, adults), shot between September and December 2018. The lungs were macroscopically examined and dissected for the detection of Metastrongylus specimens. Additionally, faecal samples were obtained from 55 animals and analysed by sedimentation/flotation and the mini-FLOTAC® method. Overall, 12′774 Metastrongylus sp. specimens were isolated: prevalence was 77.4% and mean burden 196.5 (range: 1–2589), with no significant differences between north (80.8%, 218.0) and south (71.9%, 157.4) nor between sexes and age groups. Macroscopically, dense nodular lesions associated with Metastrongylus sp. were present in 19 out of 65 (33.9%) positive lungs. Five Metastrongylus sp. were detected: M. pudendotectus (67.9%), M. salmi (63.1%), M. confusus (56%), M. apri (44%) and M. asymmetricus (17.9%), with a significant difference (p = 0.012) between north (32.7%) and south (62.5%) for M. apri. The lungworm population was female biased. The number of Metastrongylus sp. eggs in faecal samples did not correlate with worm burdens. Furthermore, the following endoparasites were detected: Isospora suis/Eimeria sp. (74.5%), Strongyloides suis (27.3%%), Trichuris suis (20.0%), Hyostrongylus rubidus/Oesophagostomum sp. (18.2%), Globocephalus sp. (9.1%), Capillaria sp. (7.3%), Ascaris suum (3.6%), Giardia sp. (3.6%) and Balantidium coli (1.8%), with significant differences for S. suis (north 36.1% > south 10.5%) and Globocephalus sp. (only south, 26.3%). Although geographically separated, both Swiss wild boar populations share similar parasite spectra, while also showing some regional idiosyncrasies partially explained by ecological and climatic factors. Despite their clinical relevance being unknown, accurate knowledge concerning the distribution of endoparasites in the wildlife reservoir is relevant to better understand risk factors for the domestic pig population.

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12′774 Metastrongylus sp. were isolated from wild boars north and south of the Alps.

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Metastrongylus prevalence was 77.4%, mean burden 196.5, five species were detected.

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No significant differences between wild boar sexes and age groups.

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Overall, similar parasite spectra with regional idiosyncrasies were identified.

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Known parasite occurrence is relevant to evaluate risk factors for domestic pigs.

Quantitative proteomics analysis of Angiostrongylus vasorum-induced alterations in dog serum sheds light on the pathogenesis of canine angiostrongylosis

Blood contains hundreds of proteins, reflecting ongoing cellular processes and immune reactions. Infections with the blood-dwelling cardiopulmonary nematode Angiostrongylus vasorum in dogs manifest with a broad spectrum of clinical signs including respiratory distress, bleeding diathesis and neurological signs, and are associated with a perturbed blood protein profile in dogs. However, current knowledge does not completely explain the observed pathologies induced by A. vasorum infections, including bleeding disorders. Using sera from experimentally infected dogs, dog serum proteome was analysed by quantitative mass spectrometry methods over several time points before and after inoculation. Following computational analysis, we identified 139 up- and downregulated proteins after infection (log2 ratio cut-off ≥ 1.0; q-value ≤ 0.05). Among upregulated proteins were chitinase 3-like 1 and pulmonary surfactant-associated protein B (log2 fold-changes ≥ 5). Pathway enrichment revealed the complement (especially the lectin pathway) and coagulation cascades as significantly affected upon analysis of downregulated proteins. Among them were mannan-binding lectin serine peptidases, ficolin, and coagulation factor XIII-B. These results bring new elements towards understanding the underlying pathomechanisms of bleeding diatheses observed in some A. vasorum-infected dogs.

Genetic diversity of the cardiopulmonary canid nematode Angiostrongylus vasorum within and between rural and urban fox populations

Angiostrongylus vasorum is an emerging parasitic cardiopulmonary nematode of dogs, foxes, and other canids. In dogs, the infection causes respiratory and bleeding disorders along with other clinical signs collectively known as canine angiostrongylosis, while foxes represent an important wildlife reservoir. Despite the spread of A. vasorum across various countries in Europe and the Americas, little is known about the genetic diversity of A. vasorum populations at a local level in a highly endemic area. Thus, in the present study, we investigated the genetic diversity of 323 adult A. vasorum nematodes from 64 foxes living in the canton of Zurich, Switzerland. Among those, 279 worms isolated from 20 foxes were analyzed separately to investigate the genetic diversity of multiple worms within individual foxes. Part of the mitochondrial cytochrome c oxidase subunit I (mtCOI) gene was amplified and sequenced. Overall, 16 mitochondrial haplotypes were identified. The analysis of multiple worms per host revealed 12 haplotypes, with up to 5 different haplotypes in single individuals. Higher haplotype diversity (n = 10) of nematodes from foxes of urban areas than in rural areas (n = 7) was observed, with 5 shared haplotypes. Comparing our data with published GenBank sequences, five haplotypes were found to be unique within the Zurich nematode population. Interestingly, A. vasorum nematodes obtained from foxes in London and Zurich shared the same dominating haplotype. Further studies are needed to clarify if this haplotype has a different pathogenicity that may contribute to its dominance. Our findings show the importance of foxes as a reservoir for genetic parasite recombination and indicate that high fox population densities in urban areas with small and overlapping home ranges allow multiple infection events that lead to high genetic variability of A. vasorum.

Feline lungworms in Greece: copromicroscopic, molecular and serological study

Aelurostrongylus abstrusus (Nematoda, Metastrongyloidea) causes verminous pneumonia in cats worldwide. This study evaluated the seroprevalence of A. abstrusus antibodies in 220 stray and free-roaming cats from insular (Mykonos, Crete, Skopelos) and continental (Thessaloniki, Attica) Greece. The results were compared with morphological and biomolecular identification of first-stage larvae (L1) in faeces. Positive cats were observed in all 5 areas: 13/97 (13.4%), 1/32 (3.1%), 7/26 (26.9%), 3/18 (16.7%) and 5/47 (10.6%) cats tested positive for A. abstrusus L1 by Baermann examination, and 33/97 (34.0%), 7/32 (21.9%), 6/26 (23.1%), 3/18 (16.7%) and 11/47 (23.4%) were seropositive, in Mykonos, Crete, Skopelos, Thessaloniki and Attica, respectively. Troglostrongylus brevior L1 were found in 12/97 (12.4%), 3/26 (11.5%) and 2/47 (4.3%) cats from Mykonos, Skopelos and Attica respectively. Six of the 220 cats (2.7%), i.e. 4/97 (4.1%) from Mykonos and 2/26 (7.7%) from Skopelos, shed L1 of both A. abstrusus and T. brevior. Sixty samples were ELISA-positive (27.3%, 95% CI: 21.5-33.7%), of which 21 (35%) tested copromicroscopically positive (19 monospecific infections and 2 mixed with Troglostrongylus brevior), and 5 were positive for T. brevior L1 only. Among seronegative cats (n = 140), L1 of A. abstrusus were additionally detected in 8 (5.7% out of 140) cats (i.e. 4 monospecific infections and 4 mixed with T. brevior), and in 6 (4.3% out of 140) cats, L1 of T. brevior as monospecific infection were detected. This study confirms the presence of lungworms in Greece and suggests that the number of cats infected with/exposed to metastrongylids is higher than detected by faecal examinations.

Field safety and efficacy of an orally administered combination of sarolaner, moxidectin and pyrantel (Simparica Trio®) for the prevention of angiostrongylosis in dogs presented as veterinary patients

Background

Infection with the cardiopulmonary nematode Angiostrongylus vasorum may cause severe disease in dogs, therefore prophylactic treatments are necessary to prevent infection in dogs at risk. A clinical field study was conducted to demonstrate the efficacy and safety of an oral combination of sarolaner, moxidectin and pyrantel (Simparica Trio^®) for the prevention of A. vasorum infection in dogs (prevention study). A survey study was conducted concurrently to determine the infection pressure in the same areas.

Methods

Prevention and survey studies were both conducted at the same veterinary clinics in endemic hot spots for A. vasorum in Denmark and Italy. The prevention study was a randomized, placebo controlled, double masked study where 622 client-owned dogs were treated and tested at 30 days intervals for 10 months. In the survey study 1628 dogs that were at risk of infection and/or were suspected to be infected were tested by fecal and/or serological methods, and the percent of dogs positive for A. vasorum was calculated.

Results

In the prevention study, there were no adverse events related to treatment with Simparica Trio^®. Two placebo-treated animals became infected with A. vasorum during the 10-month study period, while none of the dogs in the combination product-treated group became infected. In the survey study, 12.2% of the study dogs were found positive to A. vasorum, indicating high exposure to the parasite during the period of the prevention study.

Conclusions

Monthly oral treatment with the combination of sarolaner, moxidectin and pyrantel (Simparica Trio^®) was 100% effective in the prevention of natural infection with A. vasorum in dogs in highly endemic areas. In endemic areas, A. vasorum occurrence in dogs at risk is considerable.

Capillaria boehmi (syn. Eucoleus boehmi): Challenging treatment of a rarely diagnosed nasal nematode in dogs and high prevalence in Swiss foxes

Despite morphological differences of eggs and adults, Capillaria boehmi infections have been occasionally misdiagnosed as C. aerophila infections in the past. Capillaria boehmi is found in the nasal and paranasal sinuses of wild canids and dogs, which may suffer from nasal discharge, sneezing, epistaxis and, importantly, their scent can be impaired. In this study we present three challenging cases of nasal capillariosis in dogs, report and review the variable success of anthelmintic treatments and investigate C. boehmi prevalence in Swiss red foxes, considered as potential wild life reservoir. Out of two females and one male dog (all scent hounds, aged 3-9 years and weighing 19-31 kg), two dogs were previously coproscopically misdiagnosed with Trichuris infections. Two dogs showed clinical signs such as sneezing, coughing and impaired scent. From one dog adult living C. boehmi were obtained by nasal lavage. The identity of worms and eggs of all three dogs were genetically confirmed (18S rRNA, 100 % identity in 578 base pairs). Dogs 1-3 were followed-up for overall 54, 8, and 67 months, respectively. All dogs repeatedly excreted C. boehmi eggs in faecal samples despite treatments with the following compounds, in various dosage and retreatment protocols: fenbendazole, milbemycin oxime (orally), moxidectin/imidacloprid/ (spot-on) and levamisole (intramuscularly). The different anthelmintic compounds showed variable success regarding their effect on clinical outcome and on stopping egg excretion. Reinfections due to a contaminated environment could not be fully excluded. In winter 2016 and 2017, 218 foxes from the canton of Zurich, Switzerland, were examined. Tissues of nasal and paranasal sinuses were investigated for adult Capillaria specimens and eggs. We describe for the first time C. boehmi infections in Switzerland, observing a high prevalence (190/218, 87.2 %). Overall, 107 of 126 adults (84.9 %, 95 % Confidence Interval, CI: 77.5-90.7 %) and 83 of 92 youngsters (90.2 %, CI: 82.2-95.4 %) were infected. The presence of C. boehmi did not correlate with age (P = 0.209), but correlated significantly with sex: male foxes (102 of 107, 95.3 %, CI: 89.4-98.5 %) were significantly (P = 0.001) more often infected than females (88 of 111, 79.3 %, CI: 70.5-86.4 %). Worm burden ranged from 1 to 72 adult specimens (geometric mean: 5.7). In conclusion, C. boehmi infections can be mis- and/or underdiagnosed in dogs. Appropriate anthelmintic treatments, preventing coprophagia and egg contamination of the surroundings and performing coproscopic controls after treatments are fundamental aspects. Potentially, nasal washing may represent an auxiliary alternative. However, the successful elimination of C. boehmi infections in dogs remains challenging.

Efficacy of imidacloprid 10%/moxidectin 1% spot-on formulation (Advocate®) in the prevention and treatment of feline aelurostrongylosis

Background

In three randomized, controlled laboratory efficacy studies, the efficacy in the prevention of patent infections of a topical combination of imidacloprid 10%/moxidectin 1% (Advocate® spot-on formulation for cats, Bayer Animal Health GmbH) against larval stages and immature adults of Aelurostrongylus abstrusus, as well as the treatment efficacy of a single or three monthly treatments against adult A. abstrusus, were evaluated.

Methods

Cats were experimentally inoculated with 300–800 third-stage larvae (L3). Each group comprised 8 animals and the treatment dose was 10 mg/kg bodyweight (bw) imidacloprid and 1 mg/kg bw moxidectin in each study. Prevention of the establishment of patent infections was evaluated by two treatments at a monthly interval at three different time points before and after challenge infection. Curative efficacy was tested by one or three treatments after the onset of patency. Worm counts at necropsy were used for efficacy calculations.

Results

In Study 1, the control group had a geometric mean (GM) of 28.8 adult nematodes and the single treatment group had a GM of 3.4 (efficacy 88.3%). In Study 2, the control group had a GM of 14.3, the prevention group had a GM of 0 (efficacy 100%), while the treatment group had a GM of 0.1 (efficacy 99.4%). In Study 3, the GM worm burden in the control group was 32.6 compared to 0 in all three prevention groups (efficacy 100% for all of those groups).

Conclusions

The monthly administration of Advocate® reliably eliminated early larval stages and thereby prevented lung damage from and patent infections with A. abstrusus in cats. Regarding treatment, a single application of Advocate® reduced the worm burden, but it did not sufficiently clear the infection. In contrast, three monthly treatments were safe and highly efficacious against A. abstrusus.

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.

First case of a natural infection in a domestic cat (Felis catus) with the canid heart worm Angiostrongylus vasorum

Cardiopulmonary nematodes in cats include different parasite species affecting feline lungs and the heart, with the metastrongyloid Aelurostrongylus abstrusus being the most frequent feline lungworm worldwide. The present case report describes an 11-month-old male neutered European short hair cat which presented with generalised subcutaneous oedema and pleural and peritoneal effusions. According to clinical examination, abdominal imaging and laboratory analyses, a tentative diagnosis of severe glomerulopathy with massive proteinuria was made. Due to worsening of the clinical signs despite therapeutic interventions and a poor prognosis, the cat was euthanised. Necropsy and histological examinations revealed severe bilateral collagenofibrotic glomerulopathy, generalised oedema and a focal verminous pneumonia with thrombosis in arterial lung vessels containing nematode cross sections. A serum sample was tested for the presence of antibodies against the cat lungworm A. abstrusus, resulting negative. Genetic analyses confirmed the presence of nematode DNA; after exclusion of common lung and heart parasites occurring in cats, DNA of the canid heart worm nematode Angiostrongylus vasorum was identified. This is the first description of a naturally occurring infection with A. vasorum in a cat. Previous experimental studies demonstrated the development of adult male and female A. vasorum worms containing eggs in cats, but no larval excretion in the faeces. Although cats did not become patent, A. vasorum infections were clinically relevant. As A. abstrusus and A. vasorum are both gastropod transmitted nematodes, they may share the same intermediate hosts within overlapping areas. In addition, especially chronic A. abstrusus infected cats become non-patent and do not excrete L1. Considering that patent A. vasorum infections are widespread in the dog and fox population in Switzerland (and several other countries) but are apparently not patent in cats, we cannot exclude that infections with A. vasorum may occur more frequently than expected.

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Angiostrongylus vasorum is a cardiopulmonary nematode of dogs and other canids

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First natural infection of a cat (Felis catus) with Angiostrongylus vasorum

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Histological nematode sections identified in pulmonary arteries, confirmed by PCR

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Aberrant, non-patent infection in the cat with clinical relevance

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Such infections may occur more frequently particularly in highly endemic areas

Serological survey and risk factors of Aelurostrongylus abstrusus infection among owned cats in Italy

Feline lungworms affect the respiratory tract of domestic cats causing respiratory conditions of various degrees. In this study, we investigated the exposure of cats to feline lungworm infections by detecting antibodies in a large population of animals from several regions of Italy. Sera of 1087 domestic cats living in regions of the north (n = 700), the centre (n = 227) and the south (n = 160) of Italy were examined by a newly developed indirect ELISA conceived for detection of antibodies against the most frequently occurring feline lungworm Aelurostrongylus abstrusus. Individual cat data (i.e., age, sex, neutering status and provenience) were analysed as potential risk factors for exposure to lungworm infections. Samples were additionally screened for feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) proviral DNAs. Overall, 9% (98/1087; 95% confidence interval (CI) 7.4-10.9%) of the animals tested seropositive to lungworm antibodies. Positive cats were identified in the north (7.1%; CI 5.5-9.3%), in the centre (5.3%; CI 3.0-9.0%) and in the South (22.5%; CI 16.7-29.6%), with more seropositive animals in the latter area (p < 0.05). The risk of lungworm infection in cats was significantly associated with age less than 6 months (i.e. 24.4%, p < 0.05) and FIV infection (p < 0.05). This large-scale serological survey confirms the exposure of cats to lungworm infections in Italy and that serological tests can be used to assess the distribution of lungworm infections in large populations of animals.

The first seroepidemiological survey for Angiostrongylus vasorum in domestic dogs from Romania

Background

Angiostrongylus vasorum is a metastrongyloid nematode localized in the right heart and the pulmonary arteries of domestic dogs. The number of reports in Europe has recently increased, presumably as a consequence of a growing awareness among clinicians, animal owners and researchers, but also due to a growing incidence and territorial spread. So far, no studies have been conducted to assess the prevalence and distribution of A. vasorum in domestic dogs in Romania, and the awareness among veterinarians is limited or absent. The aim of the present study was to evaluate the countrywide seroprevalence of circulating antigens of A. vasorum and specific antibodies against A. vasorum in domestic dogs from Romania.

Methods

Between November 2016 and July 2017, blood was sampled from a total of 1545 domestic dogs from 23 counties of Romania. Details about their gender, age, breed, housing, use and origin were collected. All serum samples were tested for the presence of A. vasorum circulating antigens (AG) using monoclonal and polyclonal antibodies in a sandwich ELISA. Additionally, a sandwich ELISA using A. vasorum adult somatic antigen purified by monoclonal antibodies was used for specific antibody (AB) detection.

Results

A total of 33 dogs (2.14%, 95% CI: 1.82–3.56%) were seropositive for A. vasorum antigen or antibodies against the parasite. Three dogs were positive for antigen only (0.19%, 95% CI: 0.07–0.57%) and 30 dogs (1.94%, 95% CI: 1.36–2.76%) were positive for antibodies only. No dog was positive for both tests. The overall prevalence (AB or AG) and the AB prevalence were significantly higher in pure breed dogs compared to mixed breeds and mongrel dogs (P < 0.05) and in shepherd dogs compared to other groups (P < 0.05). There was no significant difference between males and females, between urban and rural dogs, between dogs with unrestricted access and with restricted access to the environment, and between dogs living outdoors and indoors.

Conclusions

Our data suggest that the disease is present in Romania in dogs, as it was previously demonstrated in foxes. However, so far, no clinical case has been reported in the country and this may be related to a low awareness among vets.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3481-0) contains supplementary material, which is available to authorized users.

Seroprevalence, biogeographic distribution and risk factors for Aelurostrongylus abstrusus infections in Swiss cats

The metastrongyloid nematode Aelurostrongylus abstrusus is a worldwide occurring feline lungworm. The spectrum of clinical signs in infected cats ranges from mild (e.g. nasal discharge or cough) to severe respiratory distress. The aim of this seroepidemiological study was to define prevalence and risk factors for A. abstrusus infections in Swiss cats, to assess the biogeographic distribution and to investigate the influence of temperature and altitude on the occurrence of this parasite. Sera of 4067 domestic cats were collected from all over Switzerland, tested for the presence of antibodies against A. abstrusus by a novel ELISA and the results correlated with biogeographic aspects. A subsample of 1000 datasets was used for risk factor analyses. Overall, 10.7% (434/4067, 95% confidence intervals [CI]: 9.7-11.7%) of the cats were tested positive, with variations from 0.0% to 20.0% among ten different biogeographic regions. Differences were significant between the Western (13.9%, CI: 11.4-16.7%) and the Eastern (9.2%, CI: 8.0-10.5%) Swiss Plateau, possibly attributable to the suitability of the areas for intermediate hosts. In total 90.3% (392/434) of the seropositive cats originated from regions lower than 700 m above sea level. Correspondingly, 98.9% (429/434) of positive samples were obtained from regions with a mean temperature higher than -2 °C in January, suggesting altitude and temperature being limiting factors for A. abstrusus infections in Switzerland. Concerning individual risk factors, prevalence was higher in intact (15.5%, CI: 9.5-23.4%) than in neutered cats (5.8%, CI: 7.9-10.4%). Young adult cats (aged 11-22 months) were significantly more often seropositive (10/76, 13.2%, CI: 6.5-22.9%) than kittens aged 1-10 months (1/34, 2.9%, CI: 0.1-15.3%) or adult and senior cats > 22 months (58/889, 6.5%, CI: 5-8.4%). Outdoor cats and cats presenting respiratory signs tend to be more often positive than indoor cats (p =  0.077) and animals without respiratory signs (p = 0.086), respectively. We here confirm that the use of a serological test can contribute to improve the identification of infected animals, through evaluation of risk factors on a population level and for a better management on an individual level, overcoming the challenges represented by faecal examinations and the correlated underestimation of the occurrence of A. abstrusus in cats.

100 Questions in Livestock Helminthology Research

An elicitation exercise was conducted to collect and identify pressing questions concerning the study of helminths in livestock, to help guide research priorities. Questions were invited from the research community in an inclusive way. Of 385 questions submitted, 100 were chosen by online vote, with priority given to open questions in important areas that are specific enough to permit investigation within a focused project or programme of research. The final list of questions was divided into ten themes. We present the questions and set them briefly in the context of the current state of knowledge. Although subjective, the results provide a snapshot of current concerns and perceived priorities in the field of livestock helminthology, and we hope that they will stimulate ongoing or new research efforts.

Angiostrongylosis in dogs with negative fecal and in-clinic rapid serological tests: 7 Cases (2013-2017)

BACKGROUND

Angiostrongylosis is considered as emerging disease in dogs in Belgium. Detection of first-stage larvae in feces using the Baermann method has an imperfect sensitivity.

OBJECTIVES

Investigation of efficacy of noninvasive blood and fecal diagnostic tests in comparison with PCR on bronchoalveolar lavage (BAL) material in a small series of coughing or dyspnoeic dogs naturally infected with Angiostrongylus vasorum.

ANIMALS

Seven dogs with angiostrongylosis.

METHODS

Retrospective study. Dogs with cough, exercise intolerance and dyspnea of 2- to 8-week duration. Diagnostic methods used included Baermann analysis, AngioDetect rapid assay, ELISAs for detection of circulating antigen and specific antibodies and qPCR on BAL material.

RESULTS

Baermann analysis, AngioDetect rapid assay, antigen ELISA, antibody ELISA, and qPCR on BAL material were positive in 3/7, 2/7, 3/6, 6/6, and 7/7 dogs, respectively. ELISA for antibodies or qPCR on BAL material were essential for definitive diagnosis in 3 dogs. Relative sensitivities of AngioDetect rapid assay, Baermann analysis, and ELISA for antigen detection were lower than 50% compared with ELISA for antibodies or qPCR on BAL material.

CONCLUSION AND CLINICAL IMPORTANCE

In this small clinical series, Baermann analysis and AngioDetect rapid assay failed to confirm the diagnosis in some dogs. Therefore, ELISA for antibody detection and qPCR on BAL material should strongly be considered in clinically suspected dogs when antigen detection methods (AngioDetect or ELISA) and Baermann analysis are negative.

Dirofilaria immitis and Angiostrongylus vasorum: The current situation of two major canine heartworms in Portugal

Cardiopulmonary nematodes are life-threatening pet parasites increasingly reported throughout Europe, with overlapping endemic areas. Dirofilaria immitis is a mosquito-borne whilst Angiostrongylus vasorum is a snail-borne pathogen. Both adult nematodes reside in the pulmonary arteries and right cardiac ventricle of domestic and wild canids, causing a wide spectrum of clinical presentations ranging from cough, dyspnoea and exercise intolerance to severe vascular and pulmonary disease with hearth failure that may lead to death. Information about the prevalence and distribution of cardiopulmonary parasites is essential for the control of animal diseases and, in the case of D. immitis, for the control of potentially associated illnesses in humans. However, in Portugal, heartworm studies are limited to few surveys and case reports, possibly underestimating the relevance of these nematodes. The present work reviews the data on cardiopulmonary dirofilariosis and angiostrongylosis in dogs in Portugal, providing a comprehensive update of the epidemiological situation during the past 20 years.

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.

Impact of heat treatment on antigen detection in sera of Angiostrongylus vasorum infected dogs

Background

In the last decade serological tests for detection of circulating Angiostrongylus vasorum antigen and specific antibodies have been developed and adopted for individual diagnosis and epidemiological studies in dogs. Although confirmed positive at necropsy, antigen detection was not possible in single experimentally, as well as naturally infected dogs, possibly due to immune complex formation. The aim of this study was to evaluate the effect of heat treatment on detection of A. vasorum antigen in sera of experimentally (n = 21, 119 follow-up sera) and naturally (n = 18) infected animals. In addition, sera of dogs showing clinical signs consistent with angiostrongylosis (n = 10), of randomly selected dogs (n = 58) and of dogs with other parasitic infections (n = 15) were evaluated. Sera were subjected to heat treatment at 100 °C after addition of 0.5 M EDTA (dilution 1:5) and tested with ELISAs for detection of circulating A. vasorum antigen before and after treatment.

Results

Between 5 and 11 weeks post-inoculation (wpi) the percentage of positive untreated samples (experimentally infected dogs) increased over time from 33.3 to 90%. Single samples were still negative between 12 and 15 wpi. Overall, between 5 and 15 wpi, 50.6% (45/89) of the available samples were seropositive. From 3 to 6 wpi EDTA/heat treatment caused a change in 8/34 (23.5%) of the samples, with most (n = 6, 17.6%) converting from positive to negative. In contrast, from 7 to 10 wpi, treatment induced a change in 19/52 (36.5%) samples, with all but one converting from negative to positive. Thirteen of 18 naturally infected dogs were antigen positive before and 15 after EDTA/heat treatment, respectively. Untreated samples of 3 dogs with suspected angiostrongylosis were antigen positive, of which only one remained positive after EDTA/heat treatment. One of 58 untreated random samples was antigen positive; this sample became negative after treatment, while another turned positive. One of 15 dogs infected with other parasites than A. vasorum was positive before but negative after treatment.

Conclusion

Although heat treatment improves A. vasorum antigen detection between 7 and 10 wpi by immune complex disruption, we do not recommend systematic pretreating sera because of reduced antigen detection between 3 and 6 wpi and impairment of antibody detection, if performed contemporaneously.

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.

Hyperfibrinolysis and Hypofibrinogenemia Diagnosed With Rotational Thromboelastometry in Dogs Naturally Infected With Angiostrongylus vasorum

Background

The pathomechanism of Angiostrongylus vasorum infection‐associated bleeding diathesis in dogs is not fully understood.

Objective

To describe rotational thromboelastometry (ROTEM) parameters in dogs naturally infected with A. vasorum and to compare ROTEM parameters between infected dogs with and without clinical signs of bleeding.

Animals

A total of 21 dogs presented between 2013 and 2016.

Methods

Dogs with A. vasorum infection and ROTEM evaluation were retrospectively identified. Thrombocyte counts, ROTEM parameters, clinical signs of bleeding, therapy, and survival to discharge were retrospectively retrieved from patient records and compared between dogs with and without clinical signs of bleeding.

Results

Evaluation by ROTEM showed hyperfibrinolysis in 8 of 12 (67%; 95% CI, 40–86%) dogs with and 1 of 9 (11%; 95% CI, 2–44%) dogs without clinical signs of bleeding (P = .016). Hyperfibrinolysis was associated with severe hypofibrinogenemia in 6 of 10 (60%; 95% CI, 31–83%) of the cases. Hyperfibrinolysis decreased or resolved after treatment with 10–80 mg/kg tranexamic acid. Fresh frozen plasma (range, 14–60 mL/kg) normalized follow‐up fibrinogen function ROTEM (FIBTEM) maximal clot firmness in 6 of 8 dogs (75%; 95% CI, 41–93%). Survival to discharge was 67% (14/21 dogs; 95% CI, 46–83%) and was not different between dogs with and without clinical signs of bleeding (P = .379).

Conclusion and Clinical Importance

Hyperfibrinolysis and hypofibrinogenemia were identified as an important pathomechanism in angiostrongylosis‐associated bleeding in dogs. Hyperfibrinolysis and hypofibrinogenemia were normalized by treatment with tranexamic acid and plasma transfusions, respectively.

Lungworms and gastrointestinal parasites of domestic cats: a European perspective

With the exception of Aelurostrongylus abstrusus, feline lungworms have been poorly studied. Information on their distribution is patchy and mostly limited to case reports. In this study, the occurrence of feline lungworms and co-infecting gastrointestinal parasites has been investigated in 12 European countries (i.e. Austria, Belgium, Bulgaria, France, Greece, Hungary, Italy, Portugal, Romania, Spain, Switzerland and the United Kingdom). An average of 10 domestic cats, with regular outdoor access, was sampled each month for 12months, and freshly passed faeces were collected. Stools were processed using a McMaster assay and a quantitative Baermann-Wetzel method. Animals positive for lungworms and/or gastrointestinal parasites were treated with a formulation containing fipronil, (S)-methoprene, eprinomectin, and praziquantel (Broadline®, Merial), and re-sampled 28days post-treatment. The association between lungworm infection and risk factors was analysed using statistical medians/means and the efficacy of the treatment against each lungworm species was assessed. Of 1990 cats sampled, 613 (30.8%) were positive for at least one parasite, while 210 (10.6%) were infected by lungworms. The prevalence of lungworm infection varied between the sampled sites, with the highest recorded in Bulgaria (35.8%) and the lowest in Switzerland (0.8%). None of the cats from Austria or the United Kingdom were infected by lungworms. Aelurostrongylus abstrusus was the species most frequently detected (78.1%), followed by Troglostrongylus brevior (19.5%), Eucoleus aerophilus (14.8%) and Oslerus rostratus (3.8%). The overall efficacy of the treatment was 99% for A. abstrusus and 100% for T. brevior, O. rostratus and E. aerophilus. Data presented provide a comprehensive account of the diagnosis, epidemiology and treatment of feline lungworms in Europe, as well as of the occurrence of co-infections by gastrointestinal parasites.

Detection of specific antibodies in cats infected with the lung nematode Aelurostrongylus abstrusus

Feline aelurostrongylosis, caused by the metastrongylid nematode Aelurostrongylus abstrusus, is an underestimated respiratory parasitosis. Its diagnosis currently mainly relies on the isolation of first stage larvae from fresh faecal samples. The aim of our study was to develop a serological test for the detection of specific antibodies against A. abstrusus by ELISA. We used recombinant major sperm protein (MSP) of the bovine lungworm Dictyocaulus viviparus as detection antigen and evaluated two different ELISA plates (Maxisorp and Immobilizer™ Amino-plate, Nunc Roskilde, Denmark) with two different enzyme systems [alkaline phosphatase (AP) and horseradish peroxidase (HRP)]. Sera from cats experimentally (n=54) and naturally (n=17) infected with A. abstrusus and from randomly selected cats with different medical issues (n=160) were used to determine sensitivity and specificity. Furthermore, cross-reactions were evaluated using sera from cats naturally (n=71) and experimentally (n=8) infected with different nematodes. A sensitivity of 100% was obtained with sera from experimentally infected cats at 10 weeks post infection using MSP on the Immobilizer™ Amino-plate with HRP, while it ranged between 90.5 and 95.2% in the other ELISA set-ups. Using sera from naturally infected cats, a sensitivity of 88.2% (95% confidence interval: 63.6-98.5%) was achieved in all four set-ups. The specificity was 85.2-94.4% in sera from uninfected cats prior to experimental infection and 68.1-90% in randomly selected cats depending on the plate and enzyme system. The number of seropositive cats increased over time post infection. Serological follow-up showed a decrease of antibody levels within 30days after anthelmintic treatment. Seropositive reactions were observed with sera from stray cats naturally infected with Toxocara cati, Capillaria sp., hookworms and Taeniidae; however, coproscopic false negative A. abstrusus findings cannot be excluded. The serological detection of specific antibodies against A. abstrusus using ELISA requires a single serum sample and therefore represents a valid alternative for reliable individual diagnosis of A. abstrusus in cats and facilitates mass screening, overcoming the usually difficult collection of cat faeces.

Prevalence of Angiostrongylus vasorum in southern Belgium, a coprological and serological survey

Background

Canine angiostrongylosis, a gastropod-borne helminthic infection, is increasingly being described in North America and is now reported in many European countries. In dogs, Angiostrongylus vasorum may cause a wide spectrum of clinical signs. Respiratory distress such as coughing and dyspnoea are the most frequently described manifestations. The aim of the present study was to gain additional information on the distribution, prevalence and risk factors associated with A. vasorum infection in dog from southern Belgium through the combined used of a commercially available in-clinic assay for detection of circulating antigen (Angio Detect™, IDEXX, Westbrook, USA) and coprology in two different canine populations: dogs with clinical signs compatible with angiostrongylosis and asymptomatic dogs or dogs presented for unrelated conditions (control).

Results

A total of 979 dogs were enrolled in the study from November 2014 until February 2016. Seven hundred fifty-seven dogs were included in the control group, whereas 222 dogs had clinical signs compatible with angiostrongylosis. Forty-six dogs out of 979 (4.7 %) had A. vasorum circulating antigen. There was a highly significant difference between the two populations (3.6 % (27/747) and 8.6 % (19/222) in control and symptomatic dogs, respectively) (P = 0.00379). First stage larvae (L1) of A. vasorum were found in seven out of 24 serologically positive control dogs and in six out of 17 serologically positive symptomatic dogs. Interestingly, L1 of Crenosoma vulpis were detected by Baermann technique in one control and nine symptomatic dogs, respectively. Out of 17 Angio Detect™ (IDEXX, Westbrook, USA) positive dogs with negative (14) or not performed Baermann test (three), one dog was positive in both in-house ELISAs (Ag and Ab) and one dog was positive for Ag. Statistical analysis was unable to detect any risk factors associated with the direct and/or indirect detection of A. vasorum.

Conclusions

This seroepidemiological study demonstrated for the first time a high seroprevalence in Southern Belgium for A. vasorum. The Angio Detect™ was found to be suitable in this context as the collection, preservation and examination of stools were difficult. Nevertheless, discrepancies were observed between the different available tests. Additional research is clearly needed. Also, coproscopy remains a very useful tool in dogs infected for less than nine weeks and for the identification of other canine lung nematodes such as C. vulpis. This study also demonstrates that asymptomatic dogs may shed A. vasorum L1 in their faeces and therefore contribute to the maintenance of A. vasorum life-cycle.

Updates on feline aelurostrongylosis and research priorities for the next decade

Feline aelurostrongylosis, caused by the metastrongyloid nematode Aelurostrongylus abstrusus, is an important gastropod-borne parasitic lung disease in cats. Infection with A. abstrusus is widespread globally, but the increasing awareness of this parasite and the advent of more sensitive diagnostics have contributed to the apparent increase in its prevalence and geographic expansion. Clinical features may range in severity from subclinical to life-threatening respiratory disease. Parasitological standard techniques, such as visualization of the nematode first larval stage in faecal and respiratory (bronchial mucus or pleural fluid) samples, remain the mainstays of diagnosis. However, diagnosis is evolving with recent advances in serological and molecular testing, which can improve the time to initiation of effective anthelmintic therapy. Despite numerous anthelmintics that are now available as treatment options, the role of host immunity and lifestyle factors in selecting cats that may benefit from more targeted anthelmintic prophylaxis or treatment practice remains unclear and is likely to guide therapeutic choices as newer data become available. This review summarizes the biology, epidemiology, pathophysiology, diagnosis and treatment options currently available for feline aelurostrongylosis.