Angiostrongylus vasorum infection in 2 dogs from Newfoundland

Described are the first antemortem diagnosis made via fecal examination using the Baermann technique and the first postmortem recovery of endemic Angiostrongylus vasorum in dogs from North America, specifically the Avalon peninsula of Newfoundland. In one dog, A. vasorum was recovered and identified at postmortem; gross and histologic lesions are described.     

Clinical signs,diagnosis and treatment of three dogs with angiostrongylosis in Ireland

: Infection with Angiostrongylus vasorum was diagnosed at necropsy on a dog that died from acute pulmonary haemorrhage, and on recovery of L1 larvae by Baermann examination of faeces from two dogs, one of which had abdominal pain and retroperitoneal haemorrhage, while the other had right-sided heart failure due to cor pulmonale. The presenting signs included syncope (one dog), exercise intolerance (two dogs), cough (two dogs), abdominal pain (one dog) and depression (one dog). One-stage prothrombin time and activated partial thromboplastin time were prolonged in two dogs, buccal mucosal bleeding time was prolonged in one dog and globulin was elevated in all three dogs. Two dogs were treated with fenbendazole and recovered.     

Serologic detection of Angiostrongylus vasorum infection in dogs

Angiostrongylus vasorum, French Heartworm, is a metastrongylid nematode infecting the pulmonary arteries and right heart of wild and domestic canids in various regions of the world. Infection in dogs can result in fatal cardiopulmonary disease. A single endemic focus of A. vasorum in North America occurs in the southeastern portion of Newfoundland, Canada. Dogs are currently diagnosed by detection of first-stage larvae shed in feces using the Baermann technique or fecal flotation. However, these procedures may lack sensitivity due to intermittent fecal larval shedding. The potential for using detection of circulating worm antigen for diagnosis was investigated by developing a sandwich-ELISA using rabbit anti-whole adult worm antiserum. This test detected circulating antigen in sera from 22/24 Baermann positive dogs naturally infected with A. vasorum. Negative results (0/52) were obtained from sera collected from Baermann negative dogs from outside of the endemic region, and from sera (0/30) from dogs from non-endemic regions that were infected with Crenosoma vulpis, the fox lung worm. Receiver operating curve analysis gave a specificity of 100% and a sensitivity of 92% for the sandwich-ELISA at an optical density cut-off of 0.19. Subsequently, 239 dogs from Newfoundland displaying clinical signs of cardiopulmonary disease, were examined using both the Baermann fecal examination and the sandwich-ELISA. Larvae were detected in 10% (24/239) of these dogs by fecal examination, whereas the sandwich-ELISA detected circulating antigen of A. vasorum in serum from 18.8% (45/239) of the dogs. This suggests that fecal diagnostics may have missed approximately half of the A. vasorum infected dogs, and that the sandwich-ELISA may be a useful tool in the diagnosis of this parasite.     

Canine angiostrongylosis: the French heartworm: an emerging threat in North America

Angiostrongylus vasorum, French heartworm, is a metastrongloid parasite found in the pulmonary arteries and right ventricle of wild and domestic canids and various other animals. The natural definitive hosts are species of foxes. The geographic distribution of the parasite includes various countries of Europe, Africa, South America, and North America. Angiostrongylosis is considered an emerging disease in dogs in Europe. In North America, autochthonous A. vasorum infection occurs only in the Canadian province of Newfoundland-Labrador. Computer modeling suggests there is a high probability that A. vasorum will spread to other parts of North America and will likely become endemic in the eastern half of the continent and in the states and provinces along the western coast. Animals acquire infection by the ingestion of gastropod or frog intermediate hosts that carry the infective 3rd-stage larvae. Frogs can also serve as paratenic hosts. Definitive antemortem diagnosis is by detection of L(1) in feces, sputum, or bronchoalveolar lavage samples. Baermann fecal examination is the most reliable method for fecal detection. However, false negative results can occur due to the typical erratic/sporadic fecal larval shedding pattern of A. vasorum. Recently, promising new methods for A. vasorum infection diagnosis have been reported involving polymerase chain reaction of blood and fecal samples and a sandwich ELISA for detection of circulating worm excretory/secretory antigen. Current treatment options include moxidectin, milbemycin oxime, and fenbendazole.     

RADIOGRAPHIC ASPECTS OF Pneumocystis carinii PNEUMONIA IN THE MINIATURE DACHSHUND

The thoracic radiographic changes of Pneumocystis carinii in 7 miniature Dachshunds were reviewed. The dogs were 7–12 months old and presented with polypnea, exercise intolerance and clinical signs suggestive of immune-incompetence. P. carinii pneumonia was diagnosed in all the dogs using transtracheal aspirate cytology and confirmed at postmortem in 3 dogs that died. Radiographically, diffuse pulmonary changes were present and varied from a mild interstitial and bronchial pattern to an alveolar pattern. Radiographic evidence of cor pulmonale was present in 1 dog. The most severe radiographic changes were seen in 2 of the dogs that died.     

Natural infections of Crenosoma vulpis and Angiostrongylus vasorum in dogs in Atlantic Canada and their treatment with milbemycin oxime

Milbemycin oxime was used to treat dogs with natural infections of the fox lungworm, Crenosoma vulpis and the French heartworm, Angiostrongylus vasorum. Crenosomosis was identified in 42 of 202 dogs with clinical signs of coughing, dyspnoea or exercise intolerance by a Baermann analysis of faecal samples taken between October 2000 and October 2001. It occurred throughout Atlantic Canada (New Brunswick, Newfoundland, Nova Scotia and Prince Edward Island). The clinical signs resolved and shedding of larvae in faeces ceased in all 32 Crenosoma-infected dogs given a single oral dose of 0.5 mg/kg milbemycin oxime for which the results of faecal examinations were available. Angiostrongylosis was identified in 16 of the 202 dogs and was restricted to the Avalon peninsula of Newfoundland, where 67 dogs were tested. The clinical signs resolved and shedding of larvae ceased in 14 of the 16 dogs treated with four, weekly oral doses of 0.5 mg/kg milbemycin oxime. One dog with severe clinical signs died during the course of treatment and one owner failed to provide a faecal sample from their dog but reported that the clinical signs had resolved.     

Haemothorax associated with Angiostrongylus vasorum infection in a dog

Angiostrongylosis was diagnosed in a dog presenting with haemothorax on the basis of detection of Angiostrongylus vasorum first-stage larvae both in the pleural effusion and in faeces. A one-year-old, male, mixed-breed dog was presented with fever, depression and persistent cough of one month's duration. Clinical examination revealed temperature of 39.5 degrees C, loud bronchovesicular sounds on thoracic auscultation and attenuated cardiac sounds. Thoracic radiographs showed a moderate bilateral pleural effusion and a diffuse interstitial pulmonary pattern, with an alveolar pattern in one lobe. Routine haematology revealed anaemia and leucocytosis with eosinophilia, basophilia and thrombocytopenia. Coagulation assays showed a consumptive coagulopathy resembling disseminated intravascular coagulation. The relationship between haemothorax and the presence of A vasorum larvae in the pleural effusion is discussed. The dog was successfully treated with fenbendazole until negative for larvae on faecal examination. This case report indicates that A vasorum infection should be considered as a possible aetiological cause of haemothorax in dogs.     

Clinical and Pathological Features of Aortic Thromboembolism in 36 Dogs

Thirty-six dogs with aortic thromboembolism were identified in a retrospective study conducted using case material from the small animal necropsy service of the University of Pennsylvania, from 1977 through 1992. No age, breed, or sex predisposition was found. Thirty dogs presented with primary complaints referable to the aortic thromboembolus and the duration of signs varied from hours to months. In 16 dogs, the presence of the thromboembolus was confirmed antemortem by ultrasound or angiography. Coagulograms were performed in 11 animals, and were consistent with consumptive hemostatic disorders in 8. The aortic occlusions were determined to be emboli in 11 dogs, associated with cardiac disease (9 dogs) and neoplastic emboli (2 dogs). In 18 dogs, the aortic occlusions were determined to be caused by primary aortic thrombi. Nine of these dogs had renal disease and four dogs had severe atherosclerosis associated with thyroid disease. In seven dogs, it could not determined if the aortic occlusions were due to primary aortic thrombi or due to emboli. In 25 dogs, the aorta was the only vessel occluded; but in 11 dogs, thrombi were identified in vessels outside of the systemic arterial system. In 9 dogs, the pulmonary arteries contained thromboemboli; one dog had thrombi in the portal vein and pulmonary arteries, and one dog a cranial vena caval thrombus. Nine of 11 dogs with multiple vascular thrombi, as well as some of the dogs with primary aortic thrombi, may have had either a propensity for thrombosis (a hypercoagulable state) or an inability to lyse thrombi (a hypothrombolytic state).     

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).     

Autochtonous infection of dogs and slugs with Angiostrongylus vasorum in Hungary

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

Eosinophilic cerebrospinal fluid pleocytosis associated with neural Angiostrongylus vasorum infection in a dog

A 1‐year‐old, female intact Pug dog was presented to the Small Animal Teaching Hospital of the University of Liverpool with a 4‐week history of progressive multifocal intracranial signs. Magnetic resonance imaging (MRI) detected multiple hemorrhagic lesions in the brain. The Baermann and zinc sulfate flotation tests with centrifugation, performed on fecal samples, were positive for lungworm larvae and an antigenic test confirmed Angiostrongylus vasorum infection. Anthelmintic treatment was started with a consequent marked clinical improvement. Seventy days later, the dog was clinically normal, and no larvae were detected on the Baermann test. Repeat MRI of the brain revealed marked improvement of the hemorrhagic lesions. Cerebrospinal fluid analysis (CSF) showed marked eosinophilic pleocytosis, and anthelmintic treatment was restarted. A follow‐up CSF analysis 4 months after the first presentation revealed resolution of the eosinophilic pleocytosis. This is the first case report of marked eosinophilic pleocytosis associated with neural A vasorum infection in a dog. The CSF eosinophilic pleocytosis persisted for several weeks after treatment, even in the absence of concurrent clinical signs and with a negative A vasorum Baermann test.     

Autochthonous infections with Angiostrongylus vasorum in dogs in Switzerland and Germany

Angiostrongylus vasorum is endemic in foxes an other carnivores in the South and south East of France, Denmark and Great Britain. The reddish nematode is present in the Arteria pulmonalis and the right side of the heart and causes respiratory and cardiovascular symptoms. From 1999 to 2004, A. vasorum was diagnosed in 5 dogs from northern Switzerland, in 1 dog from southern Germany and in 3 dogs from south Ticino. Clinical signs in the affected dogs varied and ranged from cough, tachypnoea and dyspnoea to neurological symptoms in 2 of the dogs. Four dogs died and in 3 of the 4 dogs adults and larvae were found after digestion of formalin-fixed tissue. Diagnosis in the other 5 dogs was achieved by detecting the larvae coproscopically. Based on anamnestic data, these 9 dogs are probably autochthonous cases.     

IMAGING DIAGNOSIS—PULMONARY ALVEOLAR PROTEINOSIS IN A DOG

A young dog was presented for cyanosis and right heart failure. Radiographic and CT characteristics included right heart/pulmonary artery enlargement, hepatomegaly, abdominal effusion, and severe, generalized air‐space filling. Focal increased opacities were present in the peripheral lung, as were multiple pulmonary blebs and bullae. Echocardiographic findings were consistent with cor pulmonale and pulmonary hypertension. Bronchoscopic findings were consistent with chronic inflammation. Pulmonary alveolar proteinosis (PAP) was confirmed at necropsy. Pulmonary alveolar proteinosis is an interstitial lung disease that results in accumulation of phospholipoproteinaceous material and should be included as a differential diagnosis for dogs with these clinical and imaging characteristics.     

COLLATERAL PULMONARY CIRCULATION IN DOGS EXPERIMENTALLY INFECTED WITH DIROFILARIA IMMITIS: ITS ANGIOGRAPHIC EVALUATION*

Collateral pulmonary circulation was evaluated angiographically 11 months after experimental infection of dogs with either 25 or 100 infective larvae of Dirofilaria immitis. In both groups, collateral pulmonary circulation developed from bronchial arteries and esophageal branches of the left gastric artery. Of the four dogs receiving 25 larvae, one had no detectable collateral circulation, one developed collateral pulmonary circulation from the bronchial arteries only, and two had collateral pulmonary circulation from the bronchial arteries and esophageal branches of the left gastric artery. Of the three dogs receiving 100 larvae, all had collateral pulmonary circulation from the bronchial arteries and the esophageal branches of the left gastric artery. Bronchial artery collateral pulmonary circulation was more extensive in the 100-larvae dogs than in the 25-larvae dogs. Collateral pulmonary circulation from the left gastric artery esophageal branches was similar in both dog groups. Angiographically detectable collateral pulmonary circulation developed within the first year of heaertworm infection. In some respects, the extent of collateral pulmonary circulation development was related to the severity of heartworm infection.     

Angiostrongylus vasorum (French heartworm) in a dog imported into Australia

This report describes a case of Angiostonglyus vasorum infection, sometimes referred to as French heartworm disease, in a dog imported into Western Australia from the United Kingdom. Diagnosis was made by identification of first stage larvae on fine needle aspiration of a consolidated lung lobe. First stage larvae were also identified in the faeces by the Baermann technique. The main clinical signs in this case were coughing and tachypnoea. The dog was treated successfully with fenbendazole at 50 mg/kg once daily for 10 days.     

Reversible pulmonary hypertension associated with lungworm infection in a young cat

Two ten-week-old kittens presented with dyspnea. Two weeks later dyspnea had worsened and both kittens had developed a heart murmur. One kitten died and necropsy showed severe granulomatous pneumonia and moderate bronchi(oli)tis and peribronchi(oli)tis caused by Aelurostrongylus abstrusus. The results from echocardiography, thoracic radiography and the other kitten's fecal examination were interpreted as severe parasitic pneumonia caused by A. abstrusus infection with pulmonary hypertension. Repeated administration of milbemycine-oxime and praziquantel resulted in cessation of larvae shedding and resolution of clinical, radiographic and echocardiographic signs of bronchopneumonia and pulmonary hypertension.     

Brain and spinal cord haemorrhages associated with Angiostrongylus vasorum infection in four dogs

Multifocal haemorrhages associated with Angiostrongylus vasorum infection were observed in the central nervous system of four dogs with neurological signs including depression, seizures, spinal pain and paresis. In magnetic resonance images the majority of the lesions were isointense or slightly hyperintense in T1-weighted images, hyperintense in T2-weighted images and hypointense in T2*-weighted (gradient echo) images, compatible with haemorrhages more than seven days old. Lesions were found in the brain of three of the dogs and in the spinal cord of two. The cerebrospinal fluid contained high concentrations of protein and evidence of erythrophagia. All the dogs had coagulopathy and pulmonary haemorrhage of varying severity. A vasorum larvae were detected in the faeces of each of the dogs. Neural A vasorum was confirmed at postmortem examination in two dogs.     

Angiostrongylus vasorum causing meningitis and detection of parasite larvae in the cerebrospinal fluid of a pug dog

This case report describes the presence of Angiostrongylus vasorum larvae in cerebrospinal fluid in an 11-month-old pug dog and the relative magnetic resonance images compatible with a focal meningitis. Clinical signs were compatible with a cerebellar lesion, and diagnosis was confirmed by parasitological analysis on faecal and endotracheal lavage samples. Treatment with fenbendazole and prednisolone resulted in a complete resolution of the clinical signs in two months time. A vasorum infection should be considered a possible aetiology of intracranial inflammation in dogs.     

Nematode eggs observed in cytology of cerebrospinal fluid diagnostic for intramedullary Spirocerca lupi spinal cord migration

Spinal spirocercosis due to aberrant Spirocerca lupi nematode migration is an emerging etiology for acute myelitis in dogs in Israel, causing severe, mostly nonsymmetrical hind limb paresis or paralysis, and sometimes tetraparesis or tetraparalysis. So far, incidental identification of parasites during spinal surgery or at necropsy provides the only definite diagnosis, while antemortem diagnosis of this condition has been uncertain. Specifically, antemortem diagnosis is based on the typical clinical presentation of acute, progressive, asymmetrical hind limb paresis or paralysis, with moderate to severe eosinophilic to mixed cerebrospinal fluid (CSF) pleocytosis and increased CSF protein concentration. Exclusion of other differential diagnoses also requires using spinal cord imaging. In this novel report, we document a case of an intradural spinal spirocercosis in a dog, diagnosed antemortem, by detecting S lupi eggs in the CSF, and subsequent treatment, resulting in the resolution of the clinical signs.     

Subcutaneous and cardiopulmonary dirofilariasis in a dog

Canine subcutaneous dirofilariasis is rare and typically caused by Dirofilaria repens. An adult male, intact, mixed breed dog from South Carolina, USA, was examined because of physical trauma to the right maxilla. The dog died during hospitalization and was submitted for necropsy. Gross post-mortem changes included approximately 150 adult nematodes morphologically consistent with Dirofilaria spp. in the pulmonary artery, right atrium, and right ventricle. Histologically there was widespread proliferative pulmonary endarteritis with intraluminal nematodes morphologically consistent with Dirofilaria spp. Four similar nematodes were present in the subcutaneous tissue of the left medial thigh and tibial area. These nematodes were located within the fascia and skeletal muscles. They were surrounded by epithelioid macrophages and multinucleated giant cells, with some lymphocytes and plasma cells, and areas of mineralization (interpreted as mineralized cross sections of nematodes). Nematodes were morphologically identified as D. immitis. Subcutaneous dirofilariasis caused by D. immitis occurs when migrating nematode larvae develop into adults in the subcutaneous and skeletal muscle tissues.Key clinical message:Subcutaneous dirofilariasis in dogs is rare and most often associated with Dirofilaria repens. This case highlights the pathology findings of subcutaneous D. immitis in a dog.