RESUMO
Neospora caninum is considered one of the major causes of abortion in cattle. The aim of this study was to examine and quantify the extent of the infection in cattle in a representative region of Argentina (La Pampa, province). An average sample size of 36 sera per herd was selected from 97 beef and 24 dairy herds. A total of 4334 serum samples were tested for specific anti- Neospora caninum IgG using an indirect-ELISA and 302 seropositive-ELISA sera were re-examined using an Avidity-ELISA procedure for N.caninum. The overall estimated seroprevalence for N.caninun was 9.6% (95%CI: 8.7%; 10.5%). Levels of seroprevalence were significantly different in beef 7.0% and dairy 20.3% cattle. Disease distribution seems to be associated with climatic conditions as well as the management system. Cows in the east and central regions were at a 4.5-fold and 2.0-fold higher risk, respectively, of being N. caninum seropositive compared with cows in west region. Levels of recent infection were evaluated through an avidity ELISA in seropositive animals, being registered a 0.56% and a 1.71% of recent infection in beef and dairy cattle respectively (p = 0.006). The results revealed that dairy cows had 3.1(95%CI: 1.4; 7.0) higher risk of contracting Neoporosis through horizontal transmission than beef cows. A relationship between Brucella abortus and N. caninum seroprevalence was also observed. The risk of being N. caninum seropositive was two times higher where Brucellosis seroprevalence was >3.5%. These results reveal the distribution of N. caninum infection in the cattle population in La Pampa, Argentina.
Assuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Coccidiose/veterinária , Neospora/imunologia , Animais , Anticorpos Antifúngicos/sangue , Afinidade de Anticorpos , Argentina/epidemiologia , Bovinos , Coccidiose/epidemiologia , Coccidiose/parasitologia , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/sangue , Medição de Risco , Estudos Soroepidemiológicos , Topografia MédicaRESUMO
Neospora caninum is recognized as a major cause of reproductive losses worldwide but its pathogenesis is not completely understood. Immune mediated placental pathology has been reported as being responsible for compromising pregnancy probably due to the adverse effects of exacerbated Th1 type response at the maternal-foetal interface. Different clinical outcomes are known to occur following experimental infections of cattle at different stages of gestation, with foetal death being the most common finding during early gestation, and the birth of live congenitally infected calves following infection later in gestation. The aim of the current study was to characterize the cytokine expression in the placenta of cattle experimentally challenged with tachyzoites of the Nc-1 strain during early, mid and late gestation. Moderate to severe infiltration of IL-12, IFN-γ and TNF-α expressing cells was observed in the placentas collected at early gestation and this infiltration was more pronounced in the samples collected from challenged dams carrying non-viable foetuses, compared with the mothers carrying viable foetuses. In contrast, the infiltration of Th1 cytokine expressing-cells was mild following N. caninum infection in mid gestation and scarce during infection in late gestation. Scarce expression of IL-4 was observed in the placentas from N. caninum-challenged and negative control animals throughout gestation. The milder Th1 immune response observed during later stages of gestation following Nc-1 infection could partially explain the less severe clinical outcome when compared to early pregnancy.
Assuntos
Doenças dos Bovinos/parasitologia , Coccidiose/veterinária , Citocinas/metabolismo , Neospora , Placenta/metabolismo , Placenta/parasitologia , Animais , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/metabolismo , Coccidiose/imunologia , Coccidiose/metabolismo , Coccidiose/parasitologia , Citocinas/genética , Feminino , Regulação da Expressão Gênica/imunologia , Hibridização In Situ , Placenta/imunologia , Gravidez , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Toxoplasma gondii has a very wide intermediate host range and is thought to be able to infect all warm blooded animals. The parasite causes a spectrum of different diseases and clinical symptoms within the intermediate hosts and following infection most animals develop adaptive humoral and cell-mediated immune responses. The development of protective immunity to T. gondii following natural infection in many host species has led researchers to look at vaccination as a strategy to control disease, parasite multiplication and establishment in animal hosts. A range of different veterinary vaccines are required to help control T. gondii infection which include vaccines to prevent congenital toxoplasmosis, reduce or eliminate tissue cysts in meat producing animals and to prevent oocyst shedding in cats. In this paper we will discuss some of the history, challenges and progress in the development of veterinary vaccines against T. gondii.
Assuntos
Anticorpos Antiprotozoários/imunologia , Vacinas Protozoárias/imunologia , Toxoplasma/imunologia , Toxoplasmose Animal/prevenção & controle , Animais , Interações Hospedeiro-Parasita , Toxoplasmose Animal/congênito , Toxoplasmose Animal/imunologiaRESUMO
Toxoplasma gondii has a very wide intermediate host range and is thought to be able to infect all warm blooded animals. The parasite causes a spectrum of different diseases and clinical symptoms within the intermediate hosts and following infection most animals develop adaptive humoral and cell-mediated immune responses. The development of protective immunity to T. gondii following natural infection in many host species has led researchers to look at vaccination as a strategy to control disease, parasite multiplication and establishment in animal hosts. A range of different veterinary vaccines are required to help control T. gondii infection which include vaccines to prevent congenital toxoplasmosis, reduce or eliminate tissue cysts in meat producing animals and to prevent oocyst shedding in cats. In this paper we will discuss some of the history, challenges and progress in the development of veterinary vaccines against T. gondii.