Prevalence of Neospora caninum infection in dogs from beef-cattle farms, dairy farms, and from urban areas of Argentina.
ABSTRACT Prevalence of anti-Neospora caninum antibodies was determined in sera of 320 dogs from Argentina using the indirect fluorescent antibody test (IFAT). Antibodies to N. caninum were found in 121 of 320 (37.8%) sera with titers of 1:50 (21 dogs), 1:100 (23 dogs), 1:200 (23 dogs), 1:400 (17 dogs), 1:800 (23 dogs), and > or = 1:1.600 (14 dogs). The seropositivity (IFAT, > or = 1:50) was higher in dogs from dairy (48% of 125) and beef (54.2% of 35) farms than in dogs from urban areas (26.2% of 160). Prevalence of anti-N. caninum antibodies was higher in dogs more than 12 mo of age (47.7%, 105 of 222) versus in 12-mo-old or younger dogs (12.7% of 86), suggesting postnatal exposure of N. caninum infection in dogs.
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ABSTRACT: Neospora caninum es un parásito apicomplexa que ha sido identificado como una de las principales causas de aborto en ganado bovino y responsable de patologías neurológicas en diversas especies animales. Esta íntimamente relacionado con Toxoplasma gondii, con el que comparte la habilidad para persistir dentro del hospedador por tiempo indefinido en estado latente, formando quistes tisulares que contienen en su interior parásitos con una capacidad de multiplicación reducida, denominados bradizoítos. Se compararon diferentes tratamientos a fin de inducir la conversión a bradizoíto in vitro. El tratamiento con nitroprusiato sódico 70 M durante 7 días consiguió la mejor tasa de transformación y el mejor rendimiento de vacuolas parasitóforas observadas. Además se identificaron y clonaron los genes NcSAG4 y NcBSR4 de Toxoplasma gondii, que se expresan específicamente durante el estadio de bradizoíto. Los análisis llevados a cabo sugieren que tanto NcSAG4 como NcBSR4 tendrían una regulación durante la transcripción y serían expresados de manera específica durante el estadio de bradizoíto de forma temprana o tardía, respectivamente.
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ABSTRACT: From August 2006 to 2008, 411 dogs in northeastern Brazil were evaluated for seropositivity to Neospora caninum. The dogs were clinically examined, and their owners were interviewed about the conditions in which the animals were maintained in order to assess the factors associated with infection by this parasite. A serum sample was taken from each dog for serological examination in an indirect fluorescent antibody test for N. caninum. The Yates' Chi-square test or Fisher's exact test was used to select the variables for the multivariate logistic regression model. Seropositivity was detected in 9.26% of dogs. The seropositivity rates of dogs from different environments were 2.6% (4/156) in urban areas, 13.1% (28/214) in peri-urban areas, and 14.6% (6/41) in rural areas. Factors associated with seropositivity for N. caninum were the following: contact with other dogs, access to food outside the home and residing in the peri-urban or rural environments (p<0.05). Results of this study confirm that dogs in urban, rural and peri-urban areas of northeastern Brazil are exposed to N. caninum. Control measures to prevent infection of dogs in the studied region should be focused primarily on preventing access to potential sources of infection, which include environments with other dogs, bovines, and other small intermediate hosts, such as birds and rodents.Veterinary Parasitology 09/2011; 185(2-4):305-8. · 2.38 Impact Factor
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ABSTRACT: Canines are definitive hosts of Neospora caninum (Apicomplexa). For horizontal transmission from canines to occur, viable oocysts of N. caninum must occur in the environment of susceptible intermediate hosts. Canids in Australia include wild dogs and Aboriginal community dogs. Wild dogs are those dogs that are not dependent on humans for survival and consist of the dingo, feral domestic dog and their hybrid genotypes. Aboriginal community dogs are dependent on humans, domesticated and owned by a family, but are free-roaming and have free access throughout the community. In this study the extent of N. caninum infection was determined in a total of 374 dogs (75 wild dogs and 299 Aboriginal community dogs) using a combination of microscopic, molecular and serological techniques. Oocysts of N. caninum were observed in the faeces of two juvenile Aboriginal community dogs (2/132; 1.5%). To estimate N. caninum prevalence, a new optimised cut-off of 18.5% inhibition for a commercial competitive ELISA was calculated using a two-graph receiver-operating characteristic (TG-ROC) analysis and IFAT as the gold standard resulting in equal sensitivity and specificity of 67.8%. Of the 263 dog sera tested the true prevalence of N. caninum antibodies was 27.0% (95% confidence limit: 10.3-44.1%). The association between the competitive ELISA results in dogs less than 12 month old and older dogs was significant (P=0.042). To our knowledge this is the first large scale parasitological survey of the Aboriginal community dogs and wild dogs from Australia. The high prevalence of N. caninum infection in Aboriginal community dogs illustrates that horizontal transmission of N. caninum is occurring in Australia. These results demonstrated that N. caninum in dogs is widespread, including the semi-arid to arid regions of north-western New South Wales and the Northern Territory. The populations of free-ranging dogs are likely to be important contributors to the sylvatic life cycle of N. caninum.Veterinary Parasitology 12/2011; 187(1-2):85-92. · 2.38 Impact Factor