title: Prevalence of canine heartworm (Dirofilaria immitis) disease in dogs of central Portugal.
abstract: The aim of the present study was to determine the prevalence and risk factors concerning Dirofilaria immitis infection in dogs from Figueira da Foz, located in the central region of Portugal. In the period between November 2009 and January 2011, 304 blood samples were obtained from dogs over 1 year of age, with no previous history of heartworm prevention or diagnosis. Every blood sample was analyzed using varied laboratory techniques (direct microscopic evaluation of a fresh blood sample, the modified Knott technique, and the ELISA antigen detection test - IDEXX Snapp®). In the samples in which microfilaremia was detected, a histochemical technique using acid phosphatase staining was applied to identify the species of microfilariae. A total prevalence of 27.3% (83 out of 304) was found. We also found that 73.5% of all positive cases (61 out of 83) were microfilaremic, and 26.5% were occult infections (22 out of 83). By means of a histochemical technique Dirofilaria immitis was identified in 96.7% of microfilaremic samples. A multivariate model allowed us to identify the following risk factors for the presence of heartworm disease: age between 4 and 9 years, dogs living in a rural environment, large breed dogs, and living outdoors. This study shows for the first time the high prevalence of heartworm disease in a central area of Portugal and emphasizes the importance of systematic screening for this disease, as well as the need to prevent it in dogs in this area.
authors.affiliation: Clinicão - Hospital Veterinário, 3080 Figueira da Foz, Portugal - EUVG - Escola Universitária Vasco da Gama, 3000 Coimbra, Portugal.
authors.forename: Ana Luísa
authors.initials: AL
authors.lastname: Vieira
authors.affiliation: Clinicão - Hospital Veterinário, 3080 Figueira da Foz, Portugal - EUVG - Escola Universitária Vasco da Gama, 3000 Coimbra, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Vieira
authors.affiliation: Clinicão - Hospital Veterinário, 3080 Figueira da Foz, Portugal - EUVG - Escola Universitária Vasco da Gama, 3000 Coimbra, Portugal.
authors.forename: João Manuel
authors.initials: JM
authors.lastname: Oliveira
authors.affiliation: Clinicão - Hospital Veterinário, 3080 Figueira da Foz, Portugal.
authors.forename: Ana Rita
authors.initials: AR
authors.lastname: Simões
authors.affiliation: Catedrático de Universidad. Sanidad Animal. Grupo Investigación Sanidad Animal de Galicia (INVESAGA). Animal Pathology Department, Parasitology and Parasitic Disease. Facultad de Veterinaria de Lugo, Universidad de Santiago de Compostela, 27002 Lugo, España.
authors.forename: Pablo
authors.initials: P
authors.lastname: Diez-Baños
authors.affiliation: Catedrático Jefe del Servicio de Medicina Preventiva y Salud Pública del Hospital Clínico Universitario, Facultad de Medicina y Odontología, Universidade de Santiago Compostela, España , Coordinador del Grupo de Santiago de Compostela del Centro de Investigación Biológica en Red de Epidemiología y Salud Pública (CIBERESP), y del grupo de Epidemiología del Instituto de Investigación Sanitaria (IDIS) de Santiago de Compostela, 15782 Santiago Compostela, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Gestal
mesh_terms: D000818:Animals; D009033:Culicidae / Q000469:parasitology; D004183:Dirofilaria immitis / Q000302:isolation & purification*; D004184:Dirofilariasis / Q000453:epidemiology* / Q000469:parasitology; D004197:Disease Reservoirs; D004283:Dog Diseases / Q000453:epidemiology* / Q000469:parasitology; D004285:Dogs; D005260:Female; D007303:Insect Vectors / Q000469:parasitology; D008297:Male; D008842:Microfilariae / Q000302:isolation & purification; D008954:Models, Biological; D018512:Parasitemia / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012423:Rural Health; D012621:Seasons; D014504:Urban Health