Angiostrongylus Vasorum in 20 Dogs in the Province of Chieti, Italy
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Veterinaria Italiana, 2011, 47 (1), 77‐88 Angiostrongylus vasorum in 20 dogs in the province of Chieti, Italy Elga Tieri(1), Francesco Pomilio(1), Gabriella Di Francesco(1), Maria Antonietta Saletti(1), Paolo Totaro(2), Mario Troilo(2), Silvio Menna(3), Maria Paola Tampieri(3) & Daniela Morelli(1) Summary angiostrongylosis among the differential After a case of Angiostrongylus vasorum (canine diagnoses made in clinical and post‐mortem lungworm) was diagnosed in the province of examinations of dogs in the province of Chieti Chieti (Italy) in early 2008, parasitological and in the neighbouring areas. research was conducted to investigate the Keywords presence of the parasite in dogs in the area. A Angiostrongylus vasorum, Chieti, Dog, total of 178 dogs, 56 carcasses and 122 stool Diagnosis, Italy, Nematode, Parasite, samples were examined between January and Pneumonia. September 2008. The carcasses were examined for the presence of adult parasites in the right ventricle and pulmonary artery, and larval Introduction forms in the internal organ and brain tissues. Angiostrongylosis caused by Angiostrongylus The faeces were inspected for larval form L1 vasorum (Baillet, 1866), phylum Nematoda, using three diagnostic methods that are order Strongylida, superfamily Metastrongy‐ currently used to test for endoparasites and loidea (66), is a parasitic disease that affects larvae of bronchopulmonary strongyles. A dogs and other species of Canidae, including total of 20 cases of canine angiostrongylosis foxes. were diagnosed (8.9%), with adult parasites being identified in 5 dogs, and L1 larvae in The biological cycle of A. vasorum, which is another 15. The anatomo‐pathological examin‐ only partly known, is indirect. The final host is ation of the carcasses of the dogs infested with infested by swallowing parasites belonging to adult nematodes revealed pneumonia, genera of terrestrial and aquatic gastropods (3, pleurisy, reddish foam in the trachea, effusion 30, 35), and also the common frog or other of serohaemorrhagic fluid in the thoracic paratenic hosts (6). cavity and enlarged mediastinic and The adults of A. vasorum mainly live in the mesenteric lymph nodes. Histological examin‐ right ventricle and the pulmonary artery and ation of the tissues showed serious, similar its branches (59), with rare erratic locations syndromes with lesions caused by colonisation due to the transition of the immature L5 forms of the kidneys, lymph nodes and brain by the from the capillary vessels to the pulmonary parasites. Given the large number of cases veins and subsequently to the left‐hand section confirmed in relation to the period of study of the heart and, through the systemic (9 months), it is essential to include circulation, to other organs (16, 17, 39, 41, 43, (1) Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise ‘G. Caporale’ (Istituto G. Caporale), Campo Boario, 64100 Teramo, Italy [email protected] (2) Veterinario libero professionista, Contrada Piano Saletti 14, 66020 Paglieta (CH), Italy (3) Dipartimento di Sanità Pubblica Veterinaria e Patologia Animale, Università degli Studi di Bologna, Via Tolara 50, 40064 Ozzano dell’Emilia (BO), Italy © Istituto G. Caporale 2011 www.izs.it/vet_italiana Vol. 47 (1), Vet Ital 77 Angiostrongylus vasorum in 20 dogs in the province of Chieti, Italy Elga Tieri, Francesco Pomilio, Gabriella Di Francesco, Maria Antonietta Saletti, Paolo Totaro, Mario Troilo, Silvio Menna, Maria Paola Tampieri & Daniela Morelli 48, 58). The eggs produced by adult females Netherlands (73), Sweden (1) and Switzerland located in the right‐hand portion of the heart, (67). reach the pulmonary capillaries where they The extension of the distributional area of hatch into first‐stage (L1) larvae. These larvae, canine angiostrongylosis is attributable to after reaching the lungs, perforate the capillary climatic conditions that are conducive to the and alveolar wall, aided by the animal’s development of the intermediate and paratenic coughing, reach the pharynx, and are hosts, the presence and high density of foxes swallowed and eliminated to the exterior which can act as reservoirs, and the presence through the faeces. Erratic locations of L1 in of other intermediate and final hosts which are the brain and other organs have been not yet known (7, 35, 44, 45, 67). described (20, 46, 48, 52, 54, 60, 62). In Italy, after the first case that was described The free L1 larvae in the soil are consumed by in Tuscany in 2002 (18), four cases were intermediate hosts and reach infesting stage recently observed in Tuscany and Lazio (62), L3. The cycle is completed when the dog two in Abruzzo (71) and one in Puglia (61). swallows the intermediate host with the L3 After a case of angiostrongylosis that was larvae, which mutate into L4 and L5 and reported in January 2008 in a dog from the migrate through the mesenteric lymph nodes province of Chieti, which was examined at the to the liver and pulmonary arteries, where Istituto Zooprofilattico Sperimentale dell’Abruzzo e they develop into adult forms (30, 59). del Molise ‘G. Caporale’ (Istituto G. Caporale), it Canine angiostrongylosis can be entirely was considered advisable to estimate the asymptomatic or present with clinical percentage of positive dogs among those symptoms of varying degrees of severity, up to referred to the laboratory from the same area. and including the death of the animal, depending on the number of parasites and the Materials and methods stage of development of the disease. The disease usually has a chronic course, Between January and September 2008, tests for characterised by progressive deterioration of the presence of A. vasorum were conducted on the respiratory and cardiac functions and 178 dogs from municipalities in the province of altered blood coagulation. Infested dogs may Chieti (Table I), by means of post‐mortem present frequent coughing, dyspnoea and examination of 56 carcasses and analysis of clouded sensorium (35). Bleeding diathesis, 122 stool samples provided by veterinary reduced tolerance of physical exercise, surgeons who operated in the area, anorexia, weight loss, vomiting, diarrhoea, accompanied by a form that provided the data neurological disorders, melaena and collapse and clinical symptoms of the animal. have been reported with varying frequency The right‐hand area of the heart and the (12, 21, 43, 47, 52, 61, 71, 78). pulmonary artery were tested for adult Canine A. vasorum is endemic in well‐defined parasites, in accordance with conventional areas in Denmark (5, 36, 37, 68, 70, 76, 78 ), methods (25, 29, 53). France (22, 23, 30, 59, 64), Great Britain (13, 26, Stool samples were taken from the intestine of 33, 34, 42, 52, 65), Ireland (9, 21, 40, 57, 79) and positive dogs for coprological tests. Uganda (10, 11), while sporadic cases have Histological tests were also performed on been reported in Argentina (74), Brazil (27, 28, portions of brain, heart, liver, mediastinic 38, 39), Germany (4, 50), Great Britain (52, 72), lymph nodes, spleen, lungs and kidneys. the former Soviet Union (19, 23), Switzerland The stool samples were tested for L1 larval (23), Turkey (69) and Spain (60). forms using three different diagnostic The disease has recently been reported in methods, as follows: previously unaffected areas of Canada (8, 14, . direct microscopic examination 75), England (12, 24, 32), Germany (20, 67, 68), . flotation with a heavy zinc sulphate solution Greece (51), Italy (18, 61, 62, 71), the (specific gravity 1 300 g/cm3) 78 Vol. 47 (1), Vet Ital www.izs.it/vet_italiana © Istituto G. Caporale 2011 Elga Tieri, Francesco Pomilio, Gabriella Di Francesco, Angiostrongylus vasorum in 20 dogs in the province of Chieti, Italy Maria Antonietta Saletti, Paolo Totaro, Mario Troilo, Silvio Menna, Maria Paola Tampieri & Daniela Morelli . Baermann technique Table I Municipality of origin, number of carcasses and all of which are currently used in the stool samples of dogs examined laboratory to test for endoparasites and bronchopulmonary lungworm larvae. Municipality Carcasses Stool samples Altino 2 In view of the intermittent elimination of the Archi 1 5 larvae (49, 52), after the first test the owner of Ari 1 the animal was asked for permission to take a Arielli 1 second sample to eliminate false negative Atessa 3 34 results. Using this procedure, one, two or three diagnostic tests could be performed on stool Bomba 3 samples from the same animal. One stool Canosa Sannita 1 sample was taken from 66 dogs, two from Casacanditella 1 9 dogs and three from 47 dogs; the samples Casalbordino 2 10 were taken directly from the rectum of the Casoli 1 animals at intervals of not less than 24 h. Castelfrentano 1 Fallo 1 The adult parasites and L1 larvae were Fara San Martino 1 identified on a morphological basis using the Filetto 1 identification keys described by Costa et al. Fossacesia 2 1 (15), Euzéby (25) and Rosen et al. (59). Francavilla 1 The confidence interval (CI) of the percentage Frisa 1 was determined by means of a Bayesian Gessopalena 1 approach using the Beta distribution (s+1,n‐ Guardiagrele 1 s+1) where s is the number of positives and n Lanciano 19 12 the total number of animals tested. Montazzoli 1 2 Mozzagrogna 2 4 Results Orsogna 1 The anatomo‐histopathological and parasit‐ Ortona 2 1 ological examinations indicated the presence Paglieta 2 10 of A. vasorum in 20 dogs out of the Perano 2 178 examined (8.9%, 95% CI: 7.4%‐16.7%). Pietraferrazzana 1 In particular, adult parasites were observed in Quadri 2 the right ventricle and pulmonary artery of Rocca San Giovanni 1 4 five dogs (Figs 1, 2 and 3) and L1 larvae in the Roccamontepiano 1 faeces of another 15 dogs (Figs 4 and 5). Roccaspinalveti 2 San Salvo 1 The age, gender, breed and municipality of San Vito Chietino 1 origin of the positive dogs are presented in Sant’Eusanio del 3 Table II.