Ectopic location of adult worms and first-stage larvae of Angiostrongylus vasorum in an infected dog

Is the Angiostrongylus vasorum infection in domestic dogs underestimated or misdiagnosed? A comprehensive presentation of four lethal cases

Introduction

Angiostrongylus vasorum (A. vasorum) is a widely distributed gastropod-borne nematode, causing severe cardio-pulmonary disorders in dogs. In Romania, A. vasorum was detected in foxes and serologically confirmed in domestic dogs, but no clinical cases are currently diagnosed.

Methods

Four dogs with clinical history of respiratory distress, originating from different geographical regions of Romania, were included in the study. One dog (case 1) was clinically evaluated using thoracic radiology and cardiac ultrasound; examination of feces and PCR were also performed for the etiologic diagnosis. The postmortem exam was performed in the other three cases, followed by parasitological and molecular analyses.

Results

In the first case, parasitic pneumonia was suspected based on the radiographic examination of the thorax and the infection with A. vasorum was confirmed by L1 morphological identification and PCR. The main postmortem changes included large, coalescing, dark red areas of pulmonary consolidation (n = 3) and numerous adult nematodes in the pulmonary arteries (n = 2). The histopathological examination of the lungs showed necrotizing and granulomatous pneumonia with severe hemorrhages and chronic pulmonary arterial changes. Intralesional nematodes were seen in all necropsied cases. Additional inflammatory changes related to A. vasorum infection were identified in the brain and tracheobronchial and mediastinal lymph nodes (n = 2). Identification of larvae, histopathology and PCR confirmed the infection with A. vasorum.

Conclusions

This study describes the first cases of canine cardiopulmonary angiostrongylosis in domestic dogs in Romania, and focuses on clinical presentation, pathological findings and molecular analysis. Angiostrongylosis should be included on the list of differential diagnoses of canine cardiopulmonary distress and/or haemorrhagic diathesis in Romania and awareness should be raised among clinicians to avoid post-mortem diagnosis in the future.

Hemorrhagic Meningoencephalomyelitis Due to Ectopic Localization of Aelurostrongylus abstrusus in a Cat: First Case Report

Simple Summary

Aelurostrongylus abstrusus is the most important parasitic nematode affecting cat airways worldwide. The adult nematodes live in the lungs and cause pneumonia with typical respiratory clinical signs such as cough, nasal and ocular discharge, and difficulties in breathing. The localization of adult A. abstrusus in other organs than lungs is not common. This report describes, for the first time, an unusual and fatal localization of A. abstrusus within the central nervous system of a kitten displaying neurological signs.

Abstract

The lungworm Aelurostrongylus abstrusus is one of the main causes of respiratory diseases in cats worldwide. This report describes the unusual case of a kitten infected with A. abstrusus and presented to a veterinary clinic in Brazil with lethargy, dysphagia, non-ambulatory tetraplegia, and pelvic limbs bilateral myoclonus. The clinical picture of the kitten worsened with generalized flaccid tetraplegia and death a few days after hospitalization. At necropsy, hemorrhagic necrosis and subarachnoid hemorrhages were detected in several areas of the central nervous system. Nematode stages were found at post-mortem histological examinations in lungs, cerebellum, subarachnoid space of the brain and spinal cord. Microscopic and molecular (PCRs-coupled-sequencing protocols) examination showed the presence of A. abstrusus in histological samples. This study describes the first neurological aelurostrongylosis due to ectopic localization of adult worms in the central nervous system of a cat, causing acute hemorrhagic multifocal meningoencephalomyelitis. Further studies are necessary to elucidate whether unusual localizations and the migration of A. abstrusus are more frequent than expected.

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.

Infectivity of gastropod-shed third-stage larvae of Angiostrongylus vasorum and Crenosoma vulpis to dogs

Background

Metastrongyloid parasites Angiostrongylus vasorum and Crenosoma vulpis infect wild and domestic canids and are important pathogens in dogs. Recent studies indicate that gastropod intermediate hosts infected with various metastrongyloids spontaneously shed infective third-stage larvae (L3) into the environment via feces and mucus under laboratory conditions. Shed L3 retain motility up to 120 days, but whether they retain infectivity was unknown.

Methods

To assess the infectivity of shed L3, the heart/lungs of six red foxes (Vulpes vulpes) were obtained from trappers in Newfoundland, Canada. Lungs were examined for first-stage larvae (L1) by the Baermann technique. A high number of viable A. vasorum L1 and a low number of C. vulpis L1 were recovered from one fox; these were used to infect naïve laboratory-raised Limax maximus. L3 recovered from slugs by artificial digestion were fed to two naïve purpose-bred research beagles (100 L3/dog). L1 shed by these two dogs was used to infect 546 L. maximus (2000–10,000 L1/slug). L3 shedding was induced by anesthetizing slugs in soda water and transferring them into warm (45 °C) tap water for at least 8 h. Shed L3 recovered from slugs were aliquoted on romaine lettuce in six-well tissue culture plates (80–500 L3/well) and stored at 16 °C/75% relative humidity. Four naïve research beagles were then exposed to 100 L3/dog from larvae stored for 0, 2, 4, or 8 weeks, respectively, after shedding.

Results

All four dogs began shedding C. vulpis L1 by 26–36 days post-infection (PI). All four dogs began shedding A. vasorum L1 by 50 days PI.

Conclusions

L3 infectivity for the definitive host was retained in both metastrongyloids, indicating the potential for natural infection in dogs through exposure from environmental contamination. As an additional exposure route, eating or licking plant or other material(s) contaminated with metastrongyloid L3 could dramatically increase the number of dogs at risk of infection from these parasites.

Graphic Abstract

Is Pulmonary Hypertension a Rare Condition Associated to Angiostrongylosis in Naturally Infected Dogs?

Canine angiostrongylosis due to Angiostrongylus vasorum is one of the cardiopulmonary parasitic diseases in dogs and it can manifest with very different clinical pictures, which often make diagnosis very difficult. Based on the nature of the vascular and parenchymal lesions induced by the infection (thrombo-arteritis and fibrosis), it is not surprising that cases of pulmonary arterial hypertension (PAH) associated with angiostrongylosis have been reported in the literature, although it seems to represent a rare condition. The aim of the present work is to describe the clinical and instrumental aspects referred to cases of canine angiostrongylosis before and after treatment then to evaluate even mild conditions of PAH using echocardiography. PAH was not only conventionally investigated based on characteristic cardiac changes that occur secondary to PAH and by estimating pulmonary pressure from spectral Doppler tracings, but also by using a combination of further selected echocardiographic parameters (AT/ET, PA/Ao, Pulmonary flow profile pattern) able also to reveal PAH in the absence of tricuspid or pulmonary regurgitation. Clinical and instrumental aspects of 17 cases of angiostrongylosis, divided into respiratory cases (n = 6), nonrespiratory (n = 5), and asymptomatic (n = 6), are here described. Radiographic alterations were recorded in 90% of patients despite the reason for clinical presentation. A state of mild to severe PAH was diagnosed in 58.8% of cases. Although the return to a normal clinical condition was achieved 2 months after treatment in almost all patients, radiographic and echocardiographic alterations were persistent for longer. The cases presented reinforce the evidence on the complexity of the clinical picture of angiostrongylosis. PAH associated with canine angiostrongylosis could be a more common condition than previously reported in naturally infected dogs. In some cases, echocardiographic findings suggestive of PAH could be the starting point to address the clinical diagnosis toward angiostrongylosis. PAH may be responsible for worsening of the clinical picture of patients; thus, a careful evaluation is suggested before and after anthelmintic treatment in order to optimize the therapeutic management of each case.

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

Irreversible Ocular Lesions in a Dog With Angiostrongylus Vasorum Infection

This report describes a 10-month-old dog with a sudden loss of vision and severe dyspnoea. The ocular examination revealed bilateral panuveitis, lens subluxation, secondary glaucoma, and retinal detachment. In addition, the ocular ultrasound showed in the vitreous body of the right eye, a small doubled-lined foreign body compatible with an intraocular parasite. Radiographs of the thorax revealed an increased opacity with mixed lung pattern (alveolar and bronchial) and thoracic ultrasonography showed several subpleural nodules. The presence of Angiostrongylus vasorum first stage larvae was confirmed with 324 larvae per gram of feces and an antigen test for the parasite (AngioDetect, IDEXX) also yielded a positive result. The severe and irreversible ocular lesions described in this case enhanced the complexity of the clinical picture of canine angiostrongylosis. Infection with the parasite should be included in the list of differential diagnoses for ocular uveitis to avoid potentially serious complications related to a missed or delayed diagnosis.

Angiostrongylus vasorum Causing Severe Granulomatous Hepatitis with Concurrent Multiple Acquired PSS

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

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

Background

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

Methods

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

Results

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

Conclusions

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

Electronic supplementary material

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

Comparison of coprological, immunological and molecular methods for the detection of dogs infected with Angiostrongylus vasorum before and after anthelmintic treatment

Timely diagnosis of the nematode Angiostrongylus vasorum in dogs is important in view of severe and permanent lung and cardiovascular lesions that may occur. The performance of the classical Baermann coprological method was compared with ELISAs for the serological detection of circulating antigen and specific antibodies and with Polymerase chain reaction (PCR) performed on EDTA blood, feces and tracheal swabs of serial samples from experimentally inoculated dogs over 13 weeks post inoculation (wpi) (n = 16) and following anthelmintic treatment (n = 6). Patency was observed from 6.7 to 7.6 wpi in all dogs, Baermann results were then mostly positive (116/119, 97%) during the patent period, with wide variations in the numbers of first stage larvae numbers. Blood PCR was tested positive on 1-2 occasions in 11/16 dogs in the pre-patent period, while all tested positive by antibody-detection ELISA by 6 wpi. The proportion of dogs testing positive by fecal PCR and antigen-detection ELISA rose early in the patent period. Tracheal swabs were occasionally DNA-positive in 3/16 dogs starting from 10 wpi. Following treatment, larval excretion stopped within 3 weeks and blood PCR results became negative within 1 week (5/6 dogs), while 4/6 dogs were positive for parasite DNA in tracheal swabs. Parasite antigen and specific antibodies both persisted in the blood for 3-9 weeks after treatment, with average optical densities and the proportion of positive dogs falling gradually, while results using other tests were much more variable. Results indicate that the earliest and most consistent results are obtained by the ELISAs, which can also be used for monitoring dogs after anthelmintic treatment.

Nematode dermatitis due to Angiostrongylus vasorum infection in a dog

BACKGROUND

Angiostrongylus vasorum is a nematode that primarily infects Canidae. The adult parasites are found in the pulmonary arterial circulation and the right side of the heart. The most common clinical sign is respiratory dysfunction. Bleeding, neurological, ocular, cardiovascular and gastrointestinal disorders are also reported. Skin lesions are very unusual.

HYPOTHESIS/OBJECTIVES

This report describes a nematode dermatitis due to A. vasorum infection. To the best of the authors' knowledge, this is the first case of a dog infected with this parasite that initially presented with skin lesions only.

ANIMAL

A 3-year-old female Weimaraner dog presented with a crusted papular dermatitis on the bridge of the nose and on the pinnae, and an erythematous pododermatitis with erosions and perionyxis of one digit of 1 week's duration. Two weeks later the dog developed respiratory distress.

METHODS AND RESULTS

Skin scrapings and fungal culture were negative for parasites and dermatophytes. Histopathological examination showed dermal granulomas and pyogranulomas with eosinophils centred around parasitic elements compatible with nematode larvae. Angiostrongylus vasorum DNA was demonstrated in skin biopsies. Chest radiographs were compatible with verminous pneumonia and a Baermann test revealed A. vasorum larvae. The dog was treated orally with fenbendazole, with rapid improvement and complete cure after 3 months.

CONCLUSIONS AND CLINICAL IMPORTANCE

Angiostrongylus vasorum should be considered in dogs presented with skin lesions and respiratory signs. Skin biopsy, chest radiographs and Baermann test should be included in the diagnostic investigation.

Canine angiostrongylosis: recent advances in diagnosis, prevention, and treatment

Angiostrongylus vasorum is a parasitic nematode affecting the heart and pulmonary arteries of wild (eg, foxes) and domestic canids. The parasite has an indirect life cycle in which slugs and snails act as intermediate hosts. In the last few years the parasite has spread outside the traditional endemic foci, and there is a rise of documented cases of canine angiostrongylosis across Europe. Angiostrongylus vasorum causes cardiopulmonary disorders and coagulopathies, along with different nonspecific clinical signs. Fatal infections are frequently reported. Given the severity of the infection and the recent geographic spreading of the parasite, this article reviews and discusses the current knowledge of A. vasorum, with a special focus on recent insights on diagnosis, prevention, and treatment of dog angiostrongylosis.

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

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

Dogs, cats, parasites, and humans in Brazil: opening the black box

Dogs and cats in Brazil serve as primary hosts for a considerable number of parasites, which may affect their health and wellbeing. These may include endoparasites (e.g., protozoa, cestodes, trematodes, and nematodes) and ectoparasites (i.e., fleas, lice, mites, and ticks). While some dog and cat parasites are highly host-specific (e.g., Aelurostrongylus abstrusus and Felicola subrostratus for cats, and Angiostrongylus vasorum and Trichodectes canis for dogs), others may easily switch to other hosts, including humans. In fact, several dog and cat parasites (e.g., Toxoplasma gondii, Dipylidium caninum, Ancylostoma caninum, Strongyloides stercoralis, and Toxocara canis) are important not only from a veterinary perspective but also from a medical standpoint. In addition, some of them (e.g., Lynxacarus radovskyi on cats and Rangelia vitalii in dogs) are little known to most veterinary practitioners working in Brazil. This article is a compendium on dog and cat parasites in Brazil and a call for a One Health approach towards a better management of some of these parasites, which may potentially affect humans. Practical aspects related to the diagnosis, treatment, and control of parasitic diseases of dogs and cats in Brazil are discussed.

Canine angiostrongylosis in naturally infected dogs: clinical approach and monitoring of infection after treatment

Canine angiostrongylosis is an increasingly reported disease in Europe which can be fatal if left untreated. The wide range of clinical presentation along with the absence of pathognomonic alterations can make the diagnosis challenging; thus any additional information that may provide clues to an early diagnosis may be of value, in order to ensure adequate anthelmintic treatment. Aim of the study was to assess a clinicopathological scoring system associated with natural Angiostrongylus vasorum infection diagnosed in canine patients during clinical practice, to clinically and paraclinically monitor infected dogs after treatment, and to monitor the presence of L1 larvae in faecal samples by Baermann's test. Of the total 210 enrolled animals A. vasorum infection was diagnosed in 7 dogs. These dogs were clinically and paraclinically investigated and monitored after specific treatment. Further 3 symptomatic dogs were retrospectively included in the monitoring. Results suggest that the computed scoring system can help to increase the clinical suspicion of infection particularly in asymptomatic dogs before the onset of potentially lethal lesions. Data of faecal monitoring suggested that treatment may control parasite burden but be unable to eradicate infection. Thus, a continued faecal monitoring after treatment is advisable for identification of still infected or reinfected dogs.

Rupture of the thoracic aorta associated with experimental Angiostrongylus vasorum infection in a dog

This note describes the sudden death of a dog by the rupture of the thoracic aorta caused by the presence of Angiostrongylus vasorum. A female mongrel canine with a history of weight loss and exhaustion died two hours after clinical examination. At necropsy, performed one hour after death, showed the presence of clotted blood in the thoracic cavity. Haemothorax was diagnosed. The thoracic aorta wall was thin, congested and an abnormal hole in the wall was detected approximately 0.5 cm from the entrance to the diaphragm. From clotted blood collected from the thoracic cavity, 224 first stage larvae (L1) and 15 adults of Angiostrongylus vasorum were recovered alive. Also, from a blood clot found in the aorta, four adult females and 47 L1 larvae were recovered alive. Possibly, this parasite was responsible for the aortic rupture and death of the animal.

Acute neurological signs as the predominant clinical manifestation in four dogs with Angiostrongylus vasorum infections in Denmark

Four dogs with acute neurological signs caused by haemorrhages in the central nervous system were diagnosed with Angiostrongylus vasorum infection as the underlying aetiology. Two dogs presented with brain lesions, one dog with spinal cord lesions and one with lesions in both the brain and spinal cord. Only one dog presented with concurrent signs of classical pulmonary angiostrongylosis (respiratory distress, cough), and only two dogs displayed overt clinical signs of haemorrhages. Results of coagulation assays were inconsistent. Neurological signs reflected the site of pathology and included seizures, various cranial nerve deficits, vestibular signs, proprioceptive deficits, ataxia and paraplegia. One dog died and three were euthanised due to lack of improvement despite medical treatment. This emphasises canine angiostrongylosis as a potential cause of fatal lesions of the central nervous system and the importance of including A. vasorum as a differential diagnosis in young dogs with acute neurological signs in Denmark.

Angiostrongylus vasorum infection in dogs: Presentation and risk factors

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

Larvicidal effect of imidacloprid/moxidectin spot-on solution in dogs experimentally inoculated with Angiostrongylus vasorum

A controlled, randomized, blinded dose confirmation study was conducted to evaluate the larvicidal efficacy and safety of imidacloprid 10 mg/kg/moxidectin 2.5 mg/kg body weight spot-on solution in dogs experimentally inoculated with 200 infective third stage larvae (L3) of Angiostrongylus vasorum. Twenty-four adult dogs were randomly allocated to three study groups of 8 dogs each. Animals in group 1 were treated 4 days post-inoculation (dpi), those in group 2 at 32 dpi, and the dogs in group 3 were left untreated. All dogs were euthanized and necropsied 56-59 dpi. In order to determine the worm burdens in the arterial lung vessels a method of reverse lung perfusion with phosphate buffered solution after inhibition of coagulation with heparin was applied. In the control group, excretion of first stage larvae (L1) of A. vasorum started 47-55 dpi and all dogs excreted L1 at least on one sample day before euthanasia (0.1-32.5 larvae per gram of faeces). A mean of 99 (SD 42.8) adult parasites were recovered in the post-mortem examinations in these eight control dogs. In contrast, no L1 at all were found in the faeces of dogs of groups 1 and 2, nor were any adult parasites detected at necropsy. Respiratory symptoms were observed in dogs of groups 2 and 3. Pathological findings in the lungs correlated with the treatment groups: in the animals of group 1, no or minimal lesions were found, while in all those of group 2 dispersed patterns of pale pink, slightly raised and consolidated foci were present in all lung lobes. In contrast, the lungs of the dogs from group 3 were severely affected: large confluent areas were hardened, raised and discoloured, with frequent haemorrhagic patches. Pneumonia, thrombi and parasites were histologically confirmed. The lung lymph nodes were regularly enlarged. Hence, imidacloprid/moxidectin spot-on effectively eliminated fourth stage larvae (L4) and immature adult A. vasorum in experimentally infected dogs and prevented patent infections. The earlier an infected dog was treated, the less severe were the pathological lesions observed in the lungs.

Disseminated angiostrongylosis with fatal cerebral haemorrhages in two dogs in Germany: a clinical case study

Canine angiostrongylosis is a nematode infection in domestic dogs and wild carnivores. Few single case reports describing the occurrence of this disease in Germany exist and until recently angiostrongylosis has not been considered endemic in this country. The present report focuses on clinical, pathological and parasitological findings in two cases of fatal disseminated canine angiostrongylosis associated with multifocal haemorrhages in the central nervous system. Both animals, which lived in Germany, presented with rapidly progressive neurological signs including depression, ataxia, unilateral central blindness and epileptic seizures. Blood work revealed grossly elevated D-dimers and mild thrombocytopenia. Both animals were subsequently euthanised due to progressive clinical aggravation. Necropsy showed cerebral and lung haemorrhages in both animals. Multiple sections of nematode larvae consistent with Angiostrongylus vasorum were identified on histopathological sections of the brain, heart, kidney and lung in both animals and a predominantly granulomatous inflammation with the occurrence of multinucleated giant cells was observed. Adult nematodes were found in the larger lung arteries of one dog and Angiostrongylus infection was subsequently confirmed by PCR-analysis and sequencing in both dogs. A. vasorum larvae were not detected by faecal Baermann examination performed in one of the dogs. It was concluded that canine angiostrongylosis should be considered as differential diagnosis in dogs in Germany, even if faecal examination is negative. There is currently still a lack of studies investigating the occurrence of angiostrongylosis in dogs and intermediate hosts in Germany which would be necessary to survey the endemic realities of this disease.

Pathological findings in dogs naturally infected with Angiostrongylus vasorum in Newfoundland and Labrador, Canada

Fifty-six dogs from St. John's, Newfoundland, Canada, were evaluated for Angiostrongylus vasorum infection. Small numbers of nematodes were found within pulmonary arteries of 6 dogs. Larvae were identified in fecal samples in 2 of 6 dogs. All 6 dogs had multifocal granulomatous pneumonia and sometimes foci of chronic thrombosis, which varied from very mild to severe. One dog had extensive pulmonary lesions resulting in cor pulmonale. Right heart failure was characterized by right ventricular hypertrophy, hepatic congestion, ascites, and hydrothorax. Microscopically, in most cases, eggs, larvae, and sometimes intravascular adults, were present within lung tissue sections. Small foci of granulomatous inflammation with and without larvae were present in kidney and brain in 4 dogs. An additional dog, diagnosed antemortem with angiostrongylosis via fecal examination, was also examined. Pathological findings consisted of severe pyogranulomatous interstitial pneumonia with myriad eggs, larvae, and numerous intravascular pulmonary adult nematodes with extensive arterial thrombosis. Five hundred and seventy-two adult worms were removed from pulmonary arteries. Foci of granulomatous inflammation, often associated with larvae and/or eggs, were present in tracheobronchial lymph nodes, adrenal gland, brain, and kidneys. Severe seizuring noted antemortem was attributed to several large, discrete areas of acute hemorrhagic infarction within the cerebrum and cerebellum. Natural A. vasorum infection in domestic dogs in eastern Newfoundland causes lung pathology of variable severity, which in some cases, may progress to cor pulmonale and which may be associated with extrapulmonary lesions and clinical signs.

Lungworm infections (Angiostrongylus vasorum, Crenosoma vulpis, Aelurostrongylus abstrusus) in dogs and cats in Germany and Denmark in 2003-2007

Faecal samples of 4151 dogs from Denmark, 958 dogs from Germany and 231 cats from Germany with clinical signs were examined for lungworm larvae using the Baermann funnel technique between 2003 and 2007. In total, 3.6% of Danish and German dogs shed lungworm larvae. In Denmark, patent infections of dogs with Angiostrongylus vasorum were more prevalent (2.2%) than those with Crenosoma vulpis (1.4%). In Denmark, the majority of A. vasorum- (98%) and C. vulpis-infected (80%) dogs originated from Northern Zealand. The frequency of A. vasorum and C. vulpis infections in Danish dogs obviously decreased from 2003 to 2006. In Germany, canine faecal samples were found more frequently positive for C. vulpis than for A. vasorum larvae (2.4% and 1.2%, respectively). Lungworm-infected dogs originated mainly from southern and western Germany. Larvae of Aelurostrongylus abstrusus were detected in 5.6% of cats from Germany. Overall, a distinct seasonal pattern in the detection of infected dogs was apparent for A. vasorum in Denmark and C. vulpis in Germany. The relatively high number of lungworm-infected dogs and cats indicate that these parasitic diseases should be considered in differential diagnosis of cases of treatment-resistant respiratory/cardiopulmonary distress.

Acute haemoabdomen associated with Angiostrongylus vasorum infection in a dog: a case report

A one-year-old intact female, Danish shorthaired pointer was referred to the emergency service with a history of acute collapse and pale mucous membranes after a month of reduced activity but with no other clinical signs. An ultrasound examination of the abdomen indicated the presence of a large amount of free fluid with no obvious cause such as neoplasia or splenic rupture. Fluid analysis had the macroscopic appearance of blood with no signs of infection or neoplasia. Multiple Angiostrongylus vasorum L1 larvae were revealed on a direct rectal faecal smear. The dog was treated with fenbendazole 25 mg/kg orally once daily for 20 days and given supportive treatment. The dog was stabilised on this treatment. Haemoabdomen is a clinical sign where surgical intervention is often considered an integral part of the diagnostic investigation (i.e., laparotomy) or treatment. Failing to make the diagnosis of canine angiostrongylosis before performing surgery may have a serious adverse affect on the outcome. Consequently, in areas where A. vasorum is enzootic, a Baermann test and a direct faecal smear should be included in the initial diagnostic investigation of all dogs presenting with bleeding disorders of unknown origin.

Cytological and parasitological analysis of bronchoalveolar lavage fluid for the diagnosis of Angiostrongylus vasorum infection in dogs

Bronchoalveolar lavage (BAL) is a procedure that retrieves cells and other elements from the lungs for evaluation, which helps in the diagnosis of many pulmonary diseases. The aims of this work were to perform this procedure in dogs in the acute and chronic phases of an Angiostrongylus vasorum infection for cytological analysis and to evaluate the potential of this technique as a diagnostic method for this lung-heart worm. The BAL procedure was performed through the use of an endotracheal tube on seven A. vasorum infected dogs and on five non-infected dogs lined as a control group. Sixty days post-infection (dpi) active and live larvae were retrieved from the bronchoalveolar fluid (BALF) of all infected dogs. Furthermore, in one animal it was possible to retrieve larvae in its BALF before the pre-patent period. This work reports that the A. vasorum infection resulted in an increase of relative neutrophils and eosinophils counts. In contrast, there was a significant decrease in the alveolar macrophage relative count in infected animals from 60 to 330 dpi. This study shows that the BAL is an accurate technique for the diagnosis of canine angiostrongylosis. Moreover, the technique allows us to retrieve cells and other elements that line the lung surface for cytological evaluation, which provides information about inflammatory diseases, and the diagnosis and prognosis of pulmonary parasites such as A. vasorum.

Feline aelurostrongylosis and canine angiostrongylosis: a challenging diagnosis for two emerging verminous pneumonia infections

Aelurostrongylus abstrusus and Angiostrongylus vasorum (Nematoda, Metastrongyloidea) are causative agents of verminous feline and canine pneumonia. Both are presently emerging in several geographical areas and are of major clinical importance. Given the range of parasitic and non-parasitic pathogens which may cause cardio-respiratory distress in dogs and cats, the unequivocal specific diagnosis of both diseases is pivotal for unravelling their epidemiology and central to therapy and control. Several conventional clinico-pathologic, diagnostic imaging and parasitological approaches are currently used in practice, but all have major limitations in the specific diagnosis of these diseases. Serological methods have shown promise in the diagnosis of A. abstrusus and A. vasorum infections, but no clinically useful tests are currently available. Additionally, there have been major advances in the development of novel molecular diagnostic tools for feline aelurostrongylosis, but efforts to develop molecular diagnostic tests are still preliminary for angiostrongylosis. This article provides a review of A. abstrusus and A. vasorum infections in cats and dogs, focusing on the advantages and shortcomings of classical diagnostic methodologies and on present diagnostic advances as well as future perspectives instrumental to epidemiological and clinical studies.

Canine pulmonary angiostrongylosis: an update

Canine pulmonary angiostrongylosis is an emerging snail-borne disease causing verminous pneumonia and coagulopathy in dogs. The parasite is found in Europe, North and South America and Africa, covering tropical, subtropical and temperate regions. Its distribution has been characterised by isolated endemic foci, with only sporadic occurrences outside these areas. In the last two decades, the literature has been dominated by several case reports and small case series describing sporadic disease in old or new endemic areas. Case reports and experimental studies with high doses of infective third stage larvae may not reflect what happens under field conditions. There is insufficient understanding of the spread of infection and the dynamic consequences of this parasite in the canine population. This review discusses the biology, epidemiology, clinical aspects and management of canine pulmonary angiostrongylosis.

Larval output of infected and re-infected dogs with Angiostrongylus vasorum (Baillet, 1866) Kamensky, 1905

Canine angiostrongylosis is a nematode infection in domestic dogs and wild canids. A natural infection in a domestic dog frequently leads to pneumonia, loss of physical performance, coughing, anemia, cardiac insufficiency, pulmonary fibrosis and death. The main diagnostic method is based on the finding of Angiostrongylus vasorum first-stage larvae (L1) in infected dog feces. With this objective, 11 experimentally exposed to 100 third-stage larvae (L3) per kilogram of body weight (mean = 885.45 L3/animal; S.E. = 77.7). The animals were monitored for 300 days post-single-infection (PI) and the quantity of L1 output measured. Our results showed an irregular excretion of L1 and a variation in the pre-patent period (33-76 days) and the number of L1 excreted by individual animals (1-1261 L1/g). After 300 days PI, five dogs were exposed a second time and monitored for 300 days post-re-infection (PRI) (=600 days PI). The quantity of L1 output demonstrated that double exposed dogs also presented an irregular excretion of L1 but a smaller variation in the number of L1 excreted by individual animals (4-550 L1/g).

The first report of Aelurostrongylus falciformis in Norwegian badgers (Meles meles)

The first report of Aelurostrongylus falciformis (Schlegel 1933) in Fennoscandian badgers is described. Routine parasitological examination of nine Norwegian badgers, at the National Veterinary Institute during 2004 and 2005, identified A. falciformis in the terminal airways of five of the animals. The first stage larvae (L1) closely resembled, in size and morphology, those of Angiostrongylus vasorum (Baillet 1866). The diagnosis for both A. falciformis and A. vasorum is frequently based on the identification of L1 in faeces or sputum. The potential for misclassification of an A. falciformis infection as A. vasorum, where larval identification is the only diagnostic method used, is discussed.

Helminths of red foxes (Vulpes vulpes) in Denmark

An epidemiological study of helminths in 1040 red foxes collected from various localities in Denmark during 1997-2002, revealed 21 helminth species at autopsy, including nine nematode species: Capillaria plica (prevalence 80.5%), Capillaria aerophila (74.1%), Crenosoma vulpis (17.4%), Angiostrongylus vasorum (48.6% from Northern Zealand (endemic area)), Toxocara canis (59.4%), Toxascaris leonina (0.6%), Uncinaria stenocephala (68.6%), Ancylostoma caninum (0.6%), and Trichuris vulpis (0.5%); seven cestodes: Mesocestoides sp. (35.6%), a number of Taeniid species (Taenia pisiformis, T. hydatigena, T. taeniaeformis, T. crassiceps, and unidentified Taenia spp.) (22.8%), and Echinococcus multilocularis (0.3%); four trematodes: Alaria alata (15.4%), Cryptocotyle lingua (23.8%), Pseudamphystomum truncatum (3.6% from Northern Zealand), and Echinochasmus perfoliatus (2.4% from Northern Zealand); one acanthocephalan: Polymorphus sp. (1.2%). Significant difference in prevalence was found for T. canis and A. vasorum according to host sex, and for T. canis, U. stenocephala, Mesocestoides sp., Taenia spp., A. alata, A. vasorum, and Capillaria spp. according to age groups (adult, young or cub). Prevalence and average worm intensity for each helminth species varied considerably according to geographical locality, season, and year. Aggregated distribution was found for several helminth species. The two species E. multilocularis and E. perfoliatus are first records for Denmark.