RESUMO
The aim of the present study was to characterize the specific immune response in prepubertal female calves inoculated with Neospora caninum. Forty-eight N. caninum-seronegative 6-month-old Angus female calves were randomly allocated into two groups: group A calves were inoculated subcutaneously (sc) with 1 × 106 tachyzoites of the low virulence NC-Argentina LP1 isolate in sterile phosphate-buffered saline (PBS); group B calves were mock inoculated sc with sterile PBS. Calves from group A developed a specific immune response characterized by the production of IgG antibodies and the expression of IFN-γ and TNF-α cytokines. Animals did not present any febrile reaction or reactions at the site of inoculation. Although chronic N. caninum infection was developed in 50% of calves of group A after inoculation, according to the presence of antibodies against rNc-SAG4, antigen characteristic of bradyzoites, N. caninum antibodies dropped below the cut-off of ELISA from day 210 post-inoculation onwards. Future trials using the same group of inoculated animals will allow the characterization of the evolution of the immune response during pregnancy and to determine whether the immunization with the local isolate is able to prevent congenital transmission and to protect against heterologous challenges.
Assuntos
Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/imunologia , Doenças dos Bovinos/imunologia , Coccidiose/veterinária , Neospora/imunologia , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Coccidiose/imunologia , Coccidiose/parasitologia , Citocinas/metabolismo , Feminino , Imunização/veterinária , Neospora/patogenicidade , Distribuição AleatóriaRESUMO
We carried out an inter-laboratory trial to compare the serological tests commonly used for the detection of specific Neospora caninum antibodies in cattle in Ibero-American countries. A total of eight laboratories participated from the following countries: Argentina (n = 4), Brazil (n = 1), Peru (n = 1), Mexico (n = 1), and Spain (n = 1). A blind panel of well-characterized cattle sera (n = 143) and sera representative of the target population (n = 351) was tested by seven in-house indirect fluorescent antibody tests (IFATs 1-7) and three enzyme-linked immunosorbent assays (ELISAs 1-3; two in-house and one commercial). Diagnostic performance of the serological tests was calculated and compared according to the following criteria: (1) the "Pre-test information," which uses previous epidemiological and serological data; (2) the "Majority of tests," which classifies a serum as positive or negative according to the results obtained by most tests evaluated. Unexpectedly, six tests showed either sensitivity (Se) or specificity (Sp) values lower than 90%. In contrast, the best tests in terms of Se, Sp, and area under the ROC curve (AUC) values were IFAT 1 and optimized ELISA 1 and ELISA 2. We evaluated a high number of IFATs, which are the most widely used tests in Ibero-America. The significant discordances observed among the tests regardless of the criteria employed hinder control programs and urge the use of a common test or with similar performances to either the optimized IFAT 1 and ELISAs 1 and 2.
Assuntos
Doenças dos Bovinos/diagnóstico , Coccidiose/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Neospora/isolamento & purificação , Testes Sorológicos/veterinária , Animais , Anticorpos Antiprotozoários/análise , Argentina , Brasil , Bovinos , Coccidiose/diagnóstico , Ensaio de Imunoadsorção Enzimática/métodos , Técnica Indireta de Fluorescência para Anticorpo/métodos , México , Peru , Testes Sorológicos/métodos , EspanhaRESUMO
The cyst-forming protozoan parasite Neospora caninum is one of the main causes of bovine abortion worldwide and is of great economic importance in the cattle industry. Recent studies have revealed extensive genetic variation among N. caninum isolates based on multilocus microsatellite genotyping. Currently, the most extensive study reported is based on the N. caninum genotyping of 96 samples from four countries on two continents (Spain, Argentina, Germany and Scotland) that demonstrate different clusters of multilocus genotypes (MLGs) implicated in cattle abortions as well as the population sub-structuring of N. caninum, which is partially associated with the geographical origin. The aim of this study was to genotype N. caninum from aborted bovine foetuses that originated from Mexico within the region of Aguascalientes and to investigate their genetic diversity. Parasite DNA was detected in 27 out of the 63 analysed foetuses recovered from 10 different herds. Complete or nearly complete profiles based on 9 microsatellite markers were obtained from 11 samples. Diverse N. caninum MLGs were implicated in the occurrence of abortion in each herd. All of the Mexican MLGs differed from the MLGs previously determined for the Argentinean, Spanish, German and Scottish N. caninum populations. The Mexican MLGs failed to cluster by eBURST analyses. The MLG relationships using PCoA showed a close genetic relationship between the Spanish population and a portion of the Mexican population, but a more distant genetic relationship with the Argentinean genotypes. These results demonstrate the genetic diversity of N. caninum in the studied areas that differed from other populations of N. caninum around the world.
Assuntos
Aborto Animal/parasitologia , Doenças dos Bovinos/parasitologia , Coccidiose/veterinária , Variação Genética , Neospora/genética , Complicações Parasitárias na Gravidez/veterinária , Animais , Bovinos , Coccidiose/parasitologia , Feminino , Feto/parasitologia , Genótipo , México , Repetições de Microssatélites/genética , Neospora/isolamento & purificação , Gravidez , Complicações Parasitárias na Gravidez/parasitologiaRESUMO
The objective of this study was to investigate the presence of Toxoplasma gondii- and Neospora caninum-specific antibodies in domestic South American camelids (SAC) (llamas and alpacas) from the Peruvian Andes through a cross-sectional study. A wide panel of serum samples collected from 1,845 llamas and 2,874 alpacas from the two main SAC production areas of Peru was selected. Immunofluorescence antibody technique was employed to detect and titrate specific anti-T. gondii and anti-N. caninum immunoglobulins G in serum samples. The association between T. gondii and N. caninum seroprevalence and the geographical origin (Central and South Peruvian Andes) was evaluated. Anti-T. gondii antibodies were found in 460 (24.9 %) llamas and 706 (24.6 %) alpacas, whereas anti-N. caninum antibodies were detected in 153 (8.3 %) llamas and 425 (14.8 %) alpacas. Toxoplasma gondii infection was strongly associated with the South Peruvian Andes where moderate climate conditions, larger human population, compared to the Central region, and the presence of wildlife definitive hosts could favor horizontal transmission to SAC. In contrast, N. caninum infection was not associated with the geographical region. These results indicate that T. gondii and N. caninum infections are highly and moderately widespread, respectively, in both species of domestic SAC studied in the sampled areas and appropriate control measures should be undertaken to reduce the prevalence of both parasitic infections.
Assuntos
Animais Domésticos/parasitologia , Camelídeos Americanos/parasitologia , Coccidiose/epidemiologia , Coccidiose/veterinária , Toxoplasmose Animal/epidemiologia , Animais , Anticorpos Antiprotozoários/sangue , Estudos Transversais , Técnica Direta de Fluorescência para Anticorpo/veterinária , Geografia , Neospora/imunologia , Razão de Chances , Peru/epidemiologia , Densidade Demográfica , Estudos Soroepidemiológicos , Toxoplasma/imunologiaRESUMO
Neosporosis is considered to be one of the main causes of abortions in bovines. In this study we evaluated the congenital transmission and occurrence of abortions by Neospora caninum in an embryo transfer center in Neropolis, Goiás. Serological samples from 101 recipients, 61 donors, and 90 calves were analyzed. Among these animals, 32.67% of the recipients, 22.22% of the donors, and 6.66% of the calves were positive for N. caninum. The rate of vertical transmission was 24%. There was a statistically significant difference between antibody titer of the recipient cows and the serological status of the calves. There was no statistically significant relationship between N. caninum serological status and reproductive rates such as estrum repetition and embryo production. Eight abortions occurred, six (75%) in positive females and two (25%) in negative females. These results indicate that neosporosis may be an important cause of failing reproduction and that in embryo transfer centers recipients should be previously examined, and those that are seronegative for Neospora should be chosen to reduce abortion and the birth of seropositive calves.
Assuntos
Aborto Animal/parasitologia , Doenças dos Bovinos/parasitologia , Coccidiose/veterinária , Transmissão Vertical de Doenças Infecciosas/veterinária , Neospora/imunologia , Complicações Parasitárias na Gravidez/veterinária , Aborto Animal/epidemiologia , Aborto Animal/imunologia , Animais , Animais Recém-Nascidos , Anticorpos Antiprotozoários/sangue , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/transmissão , Coccidiose/epidemiologia , Coccidiose/imunologia , Coccidiose/parasitologia , Coccidiose/transmissão , Feminino , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Gravidez , Complicações Parasitárias na Gravidez/epidemiologia , Complicações Parasitárias na Gravidez/imunologia , Complicações Parasitárias na Gravidez/parasitologiaRESUMO
A Neospora caninum 17 kDa protein fraction (p17) has been described as an immunodominant antigen (IDA) under reducing and non-reducing conditions. The aim of the present study was to investigate the diagnostic utility of p17 in cattle. In order to achieve this, p17 was purified by electroelution from whole N. caninum tachyzoite soluble extract and a p17-based Western blot (WB-p17) was developed. The p17 recognition was measured by densitometry and expressed as OD values to check the validity of the WB-p17. A total of 131 sera including sequential samples from naturally- and experimentally-infected calves and breeding cattle were analysed by WB-p17 and compared with IFAT using whole formalin-fixed tachyzoites as a reference test. The results obtained highlight the feasibility of using the N. caninum p17 in a diagnostic test in cattle. Firstly, the assay based on the p-17 antigen discriminated between known positive and negative sera from different cattle populations, breeding cattle and calves. Secondly, the p17 antigen detected fluctuations in the antibody levels and seroconversion in naturally- and experimentally-infected cattle. Significant differences in p-17 antigen recognition were observed between naturally infected aborting and non-aborting cattle, as well as significant antibody fluctuations over time in experimentally infected cattle, which varied between groups. Furthermore, the results obtained with WB-p17 are in accordance with the results obtained with the IFAT as high agreement values were obtained when all bovine subpopulations were included (kappa = 0.86).
Assuntos
Anticorpos Antiprotozoários/imunologia , Antígenos de Protozoários , Doenças dos Bovinos/diagnóstico , Coccidiose/veterinária , Epitopos Imunodominantes , Neospora/imunologia , Animais , Antígenos de Protozoários/imunologia , Western Blotting , Cruzamento , Bovinos , Doenças dos Bovinos/imunologia , Coccidiose/diagnóstico , Coccidiose/imunologia , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Estudos de Viabilidade , Técnica Indireta de Fluorescência para Anticorpo , Epitopos Imunodominantes/imunologia , Imunoglobulina G/imunologiaRESUMO
A Neospora caninum 17 kDa protein fraction (p17) has been described as an immunodominant antigen (IDA) under reducing and non-reducing conditions. The aim of the present study was to investigate the diagnostic utility of p17 in cattle. In order to achieve this, p17 was purified by electroelution from whole N. caninum tachyzoite soluble extract and a p17-based Western blot (WB-p17) was developed. The p17 recognition was measured by densitometry and expressed as OD values to check the validity of the WB-p17. A total of 131 sera including sequential samples from naturally- and experimentally-infected calves and breeding cattle were analysed by WB-p17 and compared with IFAT using whole formalin-fixed tachyzoites as a reference test. The results obtained highlight the feasibility of using the N. caninum p17 in a diagnostic test in cattle. Firstly, the assay based on the p-17 antigen discriminated between known positive and negative sera from different cattle populations, breeding cattle and calves. Secondly, the p17 antigen detected fluctuations in the antibody levels and seroconversion in naturally- and experimentally-infected cattle. Significant differences in p-17 antigen recognition were observed between naturally infected aborting and non-aborting cattle, as well as significant antibody fluctuations over time in experimentally infected cattle, which varied between groups. Furthermore, the results obtained with WB-p17 are in accordance with the results obtained with the IFAT, as high agreement values were obtained when all bovine subpopulations were included (kappa = 0.86).