RESUMO
Background: Neosporosis is a cosmopolitan disease known as the main infectious cause of abortion in cattle, reported in several states in Brazil. The transplacental transmission in cattle is responsible for perpetuating the disease in the herd. In the state of Santa Catarina, previous studies on this protozoan in cattle are mostly serological surveys. To increase information about this reproductive disorder, this work describes the diagnosis of abortions due to Neospora caninum in dairy cattle from state of Santa Catarina and the follow-up for 4 years in a farm affected by neosporosis. Cases: From 2015 to 2019, necropsy was performed on 10 aborted bovine fetuses, between fifth and eighth month of pregnancy, with 1 fetus aborted in 2015, 3 in 2016, 2 in 2017 and, 4 in 2019, all originating from the same dairy property in the southern region of state of Santa Catarina. No macroscopic lesions were found. Histopathology revealed mild to moderate multifocal mononuclear necrotizing encephalitis in 5 fetuses, and multifocal mild mononuclear myositis and myocarditis in 4 and 3 fetuses, respectively. Polymerase Chain Reaction (PCR) using primers based on the Nc-5 gene was positive for N. caninum in five fetuses. Three visits were performed in the farm for epidemiological evaluation and blood samples collection for IgG antibodies anti-N. caninum (IFAT). The total herd was 170 Jersey, Holstein and crossbred cattle, raised in a semi-confined system with mechanical milking system. Since 2014, there has been a significant increase in abortions cases, approximately 20 cows had abortions; in the year 2015, approximately 10; in 2016, less than 5; in 2017, 4 cows aborted; in 2018, 11 abortions and, in 2019, there were 4 abortions. An increase in the rate of return to estrus was also reported, and both primiparous and multiparous cows had reproductive disorders. Abortions were recorded throughout the year and occurred predominantly between the fourth and sixth month of pregnancy. In 2016, an Indirect Immunofluorescence Reaction (IFAT) was performed on sera from 26 cows (13 with a history of reproductive disorders and another 13 without disorders). Of these, 50.0% (13/26) were seropositive, with titers ranging from 100 to 1600 (cutoff ≥100). The Enzyme Immunoassay (ELISA) of the entire herd was carried out in 2017, with 26.54% (43/162) of seropositivity, 8.02% (13/162) suspect, and 30.4% (17/56) had reproductive disorders. It was observed that only animals born on the property were used for replacement, there was less possibility of direct contact between dogs on the property with milking facilities, placental and fetal remains, properly disposing of these, incinerating or burying. Thirty animals were discarded from the property, 25 of which had reproductive disorders. All young female daughters of seropositive cows remained on the property for replacement. During the evaluation period, all dogs were eliminated. Discussion: In this study, the diagnosis of neosporosis was made through epidemiology, histopathological lesions characterized by mononuclear encephalitis, myocarditis and myositis, and detection of the agent by PCR, associated with serological techniques. The lesions observed are indicative of N. caninum infection and are compatible with lesions observed in other studies. Serological screening is important to complement the diagnosis of abortion by N. caninum and to help control the agent in herds. From this report it is concluded that N. caninum is an important agent of reproductive disorders in cattle in the southern region of Santa Catarina, the different serological analyzes showed a good screening index for the inclusion of control strategies. In addition, the monitoring of reproductive rates of affected properties becomes necessary over the years, allowing better observation of control strategies.
Assuntos
Animais , Bovinos , Coccidiose/complicações , Coccidiose/veterinária , Neospora/isolamento & purificação , Aborto Animal/etiologia , Morte Fetal/etiologia , Brasil , Ensaio de Imunoadsorção Enzimática/veterináriaRESUMO
A severe outbreak of diarrhea associated with poor growth was reported in ten newly weaned goat kids that originated from a research farm (Group A). Two of these kids underwent necropsy examination. Five goat kids of the same age maintained in the same pen showed no clinical signs (Group B). The clinical, gross pathological and histopathological features of the clinically sick animals were consistent with severe coccidiosis. Group A animals had significantly lower levels of serum vitamin B12 ( 200 pg/ml) compared with group B animals (2000 pg/ml). In addition, kids belonging to group A had significantly higher Eimeria arloingi oocysts per gram (OPG) of faeces (101,400/g) compared with kids of group B (9,154/g). Microscopy and molecular tools (18S rRNA and COI genes) confirmed that the goat kids were infected with the caprine protozoan parasite E. arloingi. This study provides a definitive association between low levels of serum vitamin B12 and clinical E. arloingi infection, and also provides support to our previous studies that demonstrated how low levels of serum vitamin B12 leads to an impairment of neutrophil function and thereby potential lowered immunity to pathogens.(AU)
Um surto grave de diarreia, associado à baixo crescimento, foi relatado em dez cabritos recém-desmamados, originários de uma fazenda de pesquisa (Grupo A). Dois animais foram submetidos a exame necroscópico. Cinco cabritos da mesma idade e mantidos na mesma instalação não apresentaram sinais clínicos (Grupo B). As características clínicas e as lesões macroscópicas e microscópicas dos animais clinicamente doentes eram consistentes com coccidiose grave. Os animais do grupo A apresentaram níveis significativamente mais baixos de vitamina B12 sérica ( 200 pg / ml) em comparação com os animais do grupo B (2000 pg/ml). Além disso, os animais pertencentes ao grupo A apresentaram um número de oocistos de Eimeria arloingi por grama (OPG) de fezes (101,400/g) significativamente mais alto do que os animais do grupo B (9,154/g). As análises microscópica e molecular (genes 18S rRNA e COI) confirmaram que os cabritos estavam infectados com o protozoário E. arloingi. Este estudo fornece uma associação definitiva entre baixos níveis de vitamina B12 no soro e infecção clínica por E. arloingi. Também fornece suporte aos estudos anteriores, que demonstraram como baixos níveis de vitamina B12 no soro comprometem a função dos neutrófilos e, consequentemente, a imunidade a patógenos.(AU)
Assuntos
Animais , Cabras/metabolismo , Cabras/microbiologia , Coccidiose/complicações , Coccidiose/imunologia , Deficiência de Vitamina B 12/veterinária , EimeriaRESUMO
PURPOSE: The aim of this study was to describe for the first time a natural case of ovine abortion associated with Neospora caninum in a flock with reproductive losses in Argentina. MATERIALS AND METHODS: The analyzed flock consisted of 256 Texel sheep, of which 134 had been mated. A single blood sample was obtained by jugular vein puncture from 220 ewes (116 adult ewes, 104 yearling ewes) and 93 lambs. Serum samples and fetal fluid were tested using the indirect fluorescence antibody test to detect antibodies against N. caninum and T. gondii. Fetal and placental tissues from aborted fetus were examined by standard gross pathology procedures and were tested using histopathology and immunohistochemistry. Moreover, DNA from fetal and placental tissues was isolated and a PCR assay to detect N. caninum, T. gondii and Chlamydia spp. was used. RESULTS AND DISCUSSION: The pregnancy rate was 89% (119/134), the abortion rate was 8.4% (10/119) whereas the perinatal mortality rate was 15% (16/109). Out of 116 adult ewes sampled, 34.48% presented anti-N. caninum antibodies. Ten ewes had aborted, and one fetus was directly submitted to the diagnostic laboratory for further processing. Antibodies against N. caninum were detected in fetal fluid and in the aborted dam. Histopathological analysis in fetal tissues showed multifocal lymphohistiocytic glossitis, diffuse mild lymphohistiocytic endocarditis, pericarditis and focally extensive myocarditis. Severe multifocal necrotizing placentitis and diffuse mild lymphohistiocytic placentitis with the presence of lymphohistiocytic vasculitis were observed in placenta. N. caninum was immunolabeled in the placenta and fetal tongue. In addition, N. caninum DNA was detected in placenta, central neural system, lung and heart of the aborted fetus. There was no evidence of other infectious abortifacients in the aborted fetus. CONCLUSION: The present study described for the first time an ovine abortion caused by N. caninum in Argentina. Further investigations at a larger scale are required to establish the role of N. caninum as an important cause of reproductive losses in sheep flocks from the region.
Assuntos
Aborto Animal/parasitologia , Coccidiose/veterinária , Complicações Parasitárias na Gravidez/veterinária , Doenças dos Ovinos/parasitologia , Animais , Anticorpos Antiprotozoários/sangue , Argentina , Coccidiose/complicações , Coccidiose/imunologia , DNA de Protozoário/genética , Feminino , Feto/parasitologia , Neospora/isolamento & purificação , Gravidez , Ovinos , Doenças dos Ovinos/sangue , Toxoplasma/isolamento & purificação , Toxoplasmose Animal/sangue , Toxoplasmose Animal/imunologiaRESUMO
Our objective was to identify the direct and indirect presence of Neospora caninum in dairy cattle and their aborted fetuses from Lima, Peru. A total 219 blood samples obtained from dairy cattle with records of spontaneous abortion were collected to detect antibodies against N. caninum in serum with indirect ELISA and search for risk-factor associations. 68 fetal aborted tissue samples of these cows were analyzed by PCR, indirect ELISA and histopathology assay to detect N. caninum presence. The prevalence ratio (PR) and 95% confidence intervals (CI) were estimated. Univariate analysis was performed using the chi-squared test. Among the 68 aborted fetuses collected, 10 (15%) were positive in at least two diagnostic tests. Among 219 serum samples, 46.6% (95% CI: 40.0%-53.3%) were positive. Cows with 4 years or older (PR: 7.10; 95% CI: 4.89-10.67) and multiparous (PR: 1.76; 95% CI: 1.11-2.80) were found to be more likely to possess N. caninum antibodies. This study detects presence of N. caninum in dairy cattle and their aborted fetus from Lima valley, suggesting biosecurity management improve to neosporosis control.
Assuntos
Aborto Animal/epidemiologia , Anticorpos Antiprotozoários/sangue , Doenças dos Bovinos/epidemiologia , Coccidiose/veterinária , Neospora , Aborto Animal/parasitologia , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Coccidiose/complicações , Coccidiose/epidemiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Neospora/genética , Neospora/imunologia , Peru/epidemiologia , Reação em Cadeia da Polimerase/veterinária , Gravidez , Fatores de Risco , Estudos SoroepidemiológicosRESUMO
This is a cross-sectional study to assess the presence of antibodies in ruminants against selected pathogens associated with reproductive disorders in cattle in four Brazilian states, including the zoonotic agent Coxiella burnetii. The used tests were Virus Neutralization Assay for IBR and BVD, Microscopic Agglutination Test for Leptospira spp., Indirect Fluorescent Antibody Test (IFAT) for C. burnetii and Toxoplasma gondii, and Enzyme-Linked Immunosorbent Assay for Neospora caninum and Trypanosoma vivax. Seropositivity for C. burnetii was 13.7% with titers from 128 to 131,072; 57.8% for BoHV-1, with titers between 2 and 1,024; 47.1% for BVDV-1a, with titers from 10 to 5,120; 89.2% for N. caninum; 50% for T. vivax; and 52.0% for Leptospira spp., with titers between 100 to 800 (the following serovars were found: Tarassovi, Grippotyphosa, Canicola, Copenhageni, Wolffi, Hardjo, Pomona and Icterohaemorrhagiae); 19.6% for T. gondii with titer of 40. This is the first study that has identified C. burnetii in cattle associated with BoHV and BVDV, N. caninum, Leptospira spp., T. gondii and T. vivax. Thus, future studies should be conducted to investigate how widespread this pathogen is in Brazilian cattle herds.
Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/complicações , Doenças dos Bovinos/epidemiologia , Coccidiose/veterinária , Leptospirose/veterinária , Febre Q/veterinária , Toxoplasmose Animal/complicações , Tripanossomíase Africana/veterinária , Aborto Animal , Testes de Aglutinação , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/diagnóstico , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/virologia , Coccidiose/complicações , Coccidiose/diagnóstico , Coccidiose/epidemiologia , Coxiella burnetii/imunologia , Estudos Transversais , Vírus da Diarreia Viral Bovina/imunologia , Endometrite/etiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Infertilidade Feminina/etiologia , Leptospira/imunologia , Leptospirose/complicações , Leptospirose/diagnóstico , Leptospirose/epidemiologia , Neospora/imunologia , Febre Q/complicações , Febre Q/diagnóstico , Febre Q/epidemiologia , Estudos Soroepidemiológicos , Toxoplasma/imunologia , Toxoplasmose Animal/diagnóstico , Trypanosoma vivax/imunologia , Tripanossomíase Africana/complicações , Tripanossomíase Africana/diagnóstico , Tripanossomíase Africana/epidemiologiaRESUMO
Abstract This is a cross-sectional study to assess the presence of antibodies in ruminants against selected pathogens associated with reproductive disorders in cattle in four Brazilian states, including the zoonotic agent Coxiella burnetii. The used tests were Virus Neutralization Assay for IBR and BVD, Microscopic Agglutination Test for Leptospira spp., Indirect Fluorescent Antibody Test (IFAT) for C. burnetii and Toxoplasma gondii, and Enzyme-Linked Immunosorbent Assay for Neospora caninum and Trypanosoma vivax. Seropositivity for C. burnetii was 13.7% with titers from 128 to 131,072; 57.8% for BoHV-1, with titers between 2 and 1,024; 47.1% for BVDV-1a, with titers from 10 to 5,120; 89.2% for N. caninum; 50% for T. vivax; and 52.0% for Leptospira spp., with titers between 100 to 800 (the following serovars were found: Tarassovi, Grippotyphosa, Canicola, Copenhageni, Wolffi, Hardjo, Pomona and Icterohaemorrhagiae); 19.6% for T. gondii with titer of 40. This is the first study that has identified C. burnetii in cattle associated with BoHV and BVDV, N. caninum, Leptospira spp., T. gondii and T. vivax. Thus, future studies should be conducted to investigate how widespread this pathogen is in Brazilian cattle herds.
Resumo Este é um estudo transversal para avaliar a presença de anticorpos em ruminantes contra patógenos selecionados e associados a distúrbios reprodutivos em bovinos de quatro estados brasileiros, incluindo o agente zoonótico Coxiella burnetii. Os testes utilizados foram Teste de Vírus-Neutralização para BoHV e BVDV, teste de Aglutinação Microscópica para Leptospira spp., Reação de Imunofluorescência Indireta for C. burnetii e Toxoplasma gondii, e Ensaio de Imunoabsorção Enzimática para Neospora caninum e Trypanosoma vivax. A soropositividade para C. burnetii foi de 13,7% com títulos de 128 a 131.072; 57,8% para BoHV-1, com títulos entre 2 a 1.024; 47,1% para BVDV-1a, com títulos de 10 a 5.120; 89,2% para N. caninum; 50% para T. vivax; e 52,0% para Leptospira spp., com títulos entre 100 a 800 (sorovares encontrados: Tarassovi, Grippotyphosa, Canicola, Copenhageni, Wolffi, Hardjo, Pomona e Icterohaemorrhagiae) 19,6% para T. gondii com título de 40. Este é o primeiro estudo que evidencia a participação de C. burnetii em bovinos associada ao Vírus da Rinotraqueíte bovina infecciosa e da diarreia viral bovina, N. caninum, Leptospira spp., T. gondii e T. vivax em bovinos. Desta forma, futuros estudos devem ser conduzidos a fim de investigar o quão disseminado se encontra este patógeno em rebanhos bovinos brasileiros.
Assuntos
Animais , Feminino , Bovinos , Febre Q/veterinária , Tripanossomíase Africana/veterinária , Doença das Mucosas por Vírus da Diarreia Viral Bovina/complicações , Doenças dos Bovinos/epidemiologia , Toxoplasmose Animal/complicações , Coccidiose/veterinária , Leptospirose/veterinária , Febre Q/complicações , Febre Q/diagnóstico , Febre Q/epidemiologia , Toxoplasma/imunologia , Tripanossomíase Africana/complicações , Tripanossomíase Africana/diagnóstico , Tripanossomíase Africana/epidemiologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/diagnóstico , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Brasil/epidemiologia , Testes de Aglutinação , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/virologia , Estudos Soroepidemiológicos , Toxoplasmose Animal/diagnóstico , Estudos Transversais , Trypanosoma vivax , Coxiella burnetii/imunologia , Coccidiose/complicações , Coccidiose/diagnóstico , Coccidiose/epidemiologia , Vírus da Diarreia Viral Bovina/imunologia , Neospora/imunologia , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Aborto Animal , Endometrite/etiologia , Infertilidade Feminina/etiologia , Leptospira/imunologia , Leptospirose/complicações , Leptospirose/diagnóstico , Leptospirose/epidemiologiaRESUMO
Abstract Our objective was to identify the direct and indirect presence of Neospora caninum in dairy cattle and their aborted fetuses from Lima, Peru. A total 219 blood samples obtained from dairy cattle with records of spontaneous abortion were collected to detect antibodies against N. caninum in serum with indirect ELISA and search for risk-factor associations. 68 fetal aborted tissue samples of these cows were analyzed by PCR, indirect ELISA and histopathology assay to detect N. caninum presence. The prevalence ratio (PR) and 95% confidence intervals (CI) were estimated. Univariate analysis was performed using the chi-squared test. Among the 68 aborted fetuses collected, 10 (15%) were positive in at least two diagnostic tests. Among 219 serum samples, 46.6% (95% CI: 40.0%-53.3%) were positive. Cows with 4 years or older (PR: 7.10; 95% CI: 4.89-10.67) and multiparous (PR: 1.76; 95% CI: 1.11-2.80) were found to be more likely to possess N. caninum antibodies. This study detects presence of N. caninum in dairy cattle and their aborted fetus from Lima valley, suggesting biosecurity management improve to neosporosis control.
Resumo O objetivo do trabalho foi diagnosticar a presença direta e indireta de Neospora caninum em fetos abortados e de soros de bovinos leiteiros de Lima, Peru. Um total de 219 amostras de sangue obtido de vacas leiteiras, com registros de abortos espontâneos, foi coletado para detectar anticorpos contra N. caninum no soro (pelo ELISA indireto), e para estudar associações com fatores de risco. Foram examinadas 68 amostras de tecido fetal abortado das vacas soropositivas pela PCR, ELISA indireto e histopatologia para determinar a presença de N. caninum. A taxa de prevalência (PR) e o intervalo de confiança (CI) de 95% foram estimados. Análise univariada foi realizada usando o teste de Qui-quadrado. Entre os 68 fetos abortados, 10 (15%) foram positivos em pelo menos dois testes diagnósticos. Entre as 219 amostras de soro, 46,6% (95% IC: 40,0%-53,3%) foram positivas. Vacas com 4 anos ou mais de idade (RP: 7,10; 95% IC: 4,89-10,67) e multíparas (RP: 1,76; 95% IC: 1,11-2,80) apresentaram maior frequência de anticorpos contra N. caninum. Este estudo demonstrou a presença de N. caninum em bovinos leiteiros e em fetos abortados oriundos do vale de Lima, sugerindo a implementação de medidas de biossegurança, para o controle da neosporose.
Assuntos
Animais , Feminino , Gravidez , Bovinos , Anticorpos Antiprotozoários/sangue , Doenças dos Bovinos/epidemiologia , Coccidiose/veterinária , Neospora/genética , Neospora/imunologia , Aborto Animal/epidemiologia , Peru/epidemiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças dos Bovinos/parasitologia , Estudos Soroepidemiológicos , Reação em Cadeia da Polimerase/veterinária , Fatores de Risco , Coccidiose/complicações , Coccidiose/epidemiologia , Aborto Animal/parasitologiaRESUMO
Neospora caninum causes reproductive problems in cattle such as abortion, premature birth, retention of fetal membranes, and metritis. Therefore, this study aimed to verify possible risk factors for N. caninum infection in dairy cattle and their cause-effect relation to neosporosis. Serum samples of 1518 dairy cows from the West of Santa Catarina State, Southern Brazil were analyzed by indirect immunofluorescence assay (IFA) for N. caninum, where 466 were found to be positives (30.69%-CI95%; 28.3-33.0). In addition, an epidemiological survey was conducted in order to verify possible risk factors for neosporosis and their relation to the disease. The presence of dogs in the farm was strongly associated with IFA positive results for N. caninum, and lack of history for neosporosis in the farm increased the chances of positivity in 66%. It was found a significant cause-effect relation between the occurrence of reproductive problems and the presence of antibodies against N. caninum (p = 0.05). It is possible to conclude that N. caninum is widely distributed in dairy farms of the Western part of Santa Catarina state, Brazil, and that the occurrence of reproductive problems is directly related to the disease with the presence of dogs as a risk factor for N. caninum infection.
Assuntos
Aborto Animal/etiologia , Doenças dos Bovinos/parasitologia , Coccidiose/veterinária , Neospora/patogenicidade , Complicações na Gravidez/veterinária , Aborto Animal/epidemiologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Brasil/epidemiologia , Bovinos , Doenças dos Bovinos/sangue , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/imunologia , Coccidiose/sangue , Coccidiose/complicações , Coccidiose/epidemiologia , Doenças do Cão/parasitologia , Cães , Fazendas , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Gravidez , Complicações na Gravidez/epidemiologia , Complicações na Gravidez/etiologia , Fatores de Risco , Estudos SoroepidemiológicosRESUMO
The purpose of this study was to use mixed logistic regression to evaluate the association between Neospora caninum serostatus and abortion, accounting for the effects of farms. The main objective was to explore the interpretation of this model and discuss the contribution of this analysis to our understanding of the disease's epidemiology. A mixed-effects logistic model using farms as a random effect and the serostatus for N. caninum, age of cattle and farm location as fixed effects was performed. The data from 1256 cows over 15 months of age from 60 farms were used, and the abortion information was obtained from farm records. A significant association between N. caninum serostatus and abortion was found (p<0.0001). Seropositive cows had 6.63 times greater odds of having a history of previous abortion (95% CI: 4.35-13.37). There was remarkable variability across farms in the probability of a cow having a history of an abortion. Including the effects of the farms in the regression, it was possible to estimate an intraclass correlation coefficient (ICC) of 16%. That means that 16% of the variation in abortion occurrence that was not explained by the fixed effects was due to farms. In practical terms, this variation means that while there are farms with several seropositive cows and no/few abortion cases, the opposite is also true, with a high number of abortions in farms with low/medium seroprevalence. The remaining variability (84%) was not explained by the effect of N. caninum, age, region, and the effect of farms, i.e., it is due to unknown factors that are causing abortions. The results of this study reinforce the importance of N. caninum as a cause of abortions and demonstrate the significant heterogeneity in the probability of a cow having a history of an abortion that cannot be explained completely by N. caninum serostatus, age or location. Including the hierarchical structure of the population along with correct interpretation of the model estimates helps us understand the effect of the farms, i.e., the probability of a cow abortion conditional to the farms, which also contributes to our understanding of the epidemiology of abortions caused by neosporosis. The use of hierarchical models and reporting the ICC should be encouraged.
Assuntos
Aborto Animal/epidemiologia , Doenças dos Bovinos/epidemiologia , Coccidiose/veterinária , Neospora/imunologia , Aborto Animal/etiologia , Aborto Animal/parasitologia , Animais , Bovinos , Doenças dos Bovinos/etiologia , Doenças dos Bovinos/parasitologia , Coccidiose/complicações , Coccidiose/epidemiologia , Coccidiose/parasitologia , Indústria de Laticínios , Feminino , Modelos Logísticos , Neospora/isolamento & purificação , Gravidez , Estudos SoroepidemiológicosRESUMO
Sera from 112 mares from 5 horse-breeding farms was examined for the presence of antibodies to Neospora caninum and Toxoplasma gondii by an indirect fluorescent antibody test (IFAT), as well as from dogs and cattle present on these properties for the presence of antibodies to N. caninum. Among the 112 mares, 35 had a history of reproductive problems in the last breeding season and 77 had no reproductive problems. The rates of seroprevalence of N. caninum in mares with and without a history of reproductive problems were 25.71% and 6.49% and from T. gondii 2.85% and 1.29%, respectively. In dogs and cattle, the rates of seroprevalence of N. caninum were 10.52% and 15.55%, respectively. A positive correlation was found between the presence of antibodies against N. caninum (p=0.010) in mares and the occurrence of reproductive problems using the Fisher's exact test. Significantly higher seroprevalence for N. caninum in mares was observed on the farm that had seropositive dogs (p=0.018). Cattle on this farm were also seropositive. No significant differences in seropositivity were found on farms where dogs were seronegative, or absent. This result suggests, for the first time, the presence of seropositive dogs as a risk factor for N. caninum in mares and the necessity for further investigation of the epidemiology of this parasite in horse-breeding farms with reproductive problems and the presence of cattle and dogs. This is the first report on the occurrence of antibodies against N. caninum in horses from the state of Santa Catarina, Brazil.