IgM e IgG como marcadores da infecção transplacentária por Neospora caninum em fetos bovinos

Experimental infection of tachyzoites of the NC1 strain of Neosporacaninum in female swine

Neospora caninum is a protozoan that can cause reproductive problems in several animal species. Although N. caninum infection has been reported in swine, the pathogenesis and clinical signs are not fully known in this species. The objective of this work was to evaluate the effect of experimental infection with tachyzoites of the N. caninum strain Nc1 in swine matrices at different stages of gestation. For that purpose, 12 gilts, seronegative for N. caninum and T. gondii, were selected and allocated into four groups of three animals each. Animals in group A were not inoculated (control) and animals in groups B, C, and D were inoculated intravenously with of 2.9 × 10⁷ tachyzoites, 30 days before conception, and at 45 and 90 days of gestation, respectively. Temperature, heart rate, blood, saliva, and vaginal mucus samples from the animals were collected periodically until the time of delivery for the investigation of IgG and IgM antibodies against N. caninum using IFAT and PCR to detect the parasite DNA. All gilts sero-converted from 5 and 7 DPI (days postinoculation) to IgM and IgG, respectively. Two gilts showed hypothermia on the 5th and 7th DPI, and five inoculated animals had leukocytosis on the 7th DPI. It was possible to detect DNA of N. caninum in samples of saliva (33/84), vaginal mucus (17/84), and blood (2/84). Based on serology (IgM) and PCR, three animals in group B showed evidence of reappearance of the infection during pregnancy. It is concluded that N. caninum can cause clinical signs in infected swine females, in addition to indicating saliva as a suitable diagnostic biological material for the detection of N. caninum DNA in this animal species.

Meta-analysis of the prevalence and risk factors associated with bovine neosporosis

Neospora caninum is one of the main infectious agents that cause reproductive disorders in cattle. However, knowledge about the prevalence and causal factors of bovine neosporosis is needed in order to establish control measures. The purpose of this study was to estimate the pooled prevalence and determine the risk factors of bovine neosporosis using meta-analytic methods. Searches for data on N. caninum seroprevalence and potential risk factors were conducted in the PubMed, LILACS, and SciElo databases. The random effects model was used for the meta-analysis of the included studies. The pooled prevalence of N. caninum in cattle was 24% (95% confidence interval (CI), 19-29) in North and Central America, 24% (95% CI, 20-28) in South America, 18% (95% CI, 14-21) in Asia, 15% (95% CI, 12-18) in Europe, 13% (95% CI, 11-16) in Africa, and 8% (95% CI, 4-14) in Oceania. A significant correlation was found between N. caninum infection and abortion in cows (odds ratio (OR) = 2.66, 95% CI, 1.97-3.59). The following risk factors were signicantly associated with N. caninum seroprevalence: presence of dogs on the farm (OR = 2.84; 95% CI, 1.40-5.80) and the type of cattle production system, with dairy cattle being more susceptible to bovine neosporosis (OR = 1.60; 95% CI, 1.16-2.19) than beef cattle. The adoption of measures to prevent the dissemination of N. caninum in cattle herds is suggested, aiming to reduce the economic losses incurred to the dairy and beef industry.

Neospora caninum em bovinos em matadouros de Pernambuco e Alagoas

A neosporose bovina é uma doença infecciosa causada pelo Neospora caninum, parasito intracelular obrigatório, sendo considerada uma das principais causas de aborto na espécie bovina em diversos países. Objetivou-se estudar a ocorrência de N. caninum em vacas e fetos nos Estados de Pernambuco e Alagoas, Brasil. Foram coletadas 306 amostras de soro sanguíneo de vacas abatidas causada pelo Neospora caninum, parasito intracelular obri-e 30 fetos nos Estados de Pernambuco e Alagoas. Para o gatório, sendo considerada uma das principais causas de diagnóstico sorológico utilizou-se a técnica de Reação de aborto na espécie bovina em diversos países. Objetivou-se Imunoflurescência Indireta (RIFI) com ponto de corte estudar a ocorrência de N. caninum em vacas e fetos nos 1:200 para os soros das vacas e para os soros fetais utilizou Estados de Pernambuco e Alagoas, Brasil. Foram coletadas 306 amostras de soro sanguíneo de vacas abatidas e 30 fetos nos Estados de Pernambuco e Alagoas. Para o diagnóstico sorológico utilizou-se a técnica de Reação de Imunoflurescência Indireta (RIFI) com ponto de corte 1:200 para os soros das vacas e para os soros fetais utilizou ponto de corte 1:25. Para a pesquisa do DNA parasitário utilizaram-se tecidos fetais submetidos à técnica da Reação em Cadeia da Polimerase (PCR). Na sorologia, observou-se 39/306 (12,6%) das vacas positivas e 5/30 (16,7%) dos fetos positivos. Na detecção do parasito 8/30 (26,6%) dos fetos foram positivos na PCR. Os resultados obtidos neste estudo quanto à presença do parasito nos fetos são inéditos para a região estudada e permitem concluir que este agente deve ser incluído no estudo das causas de aborto na espécie bovina nesta região do Brasil.