[Efficiency of bacteriological culture and the immunofluorescent assay to detect Campylobacter fetus in bovine genital fluids]

Isolation of Campylobacter fetus subsp. venerealis from seminal vesicle of a naturally challenged bull

Campylobacter fetus is a well-recognized pathogen that affects reproductive rate in cattle. In the present study, two Angus bulls were kept (39 days) separately with a group of heifers experimentally infected with Campylobacter fetus subsp. venerealis (Cfv) and Campylobacter fetus subsp. venerealis biovar intermedius (Cfvi), respectively. Each bull resulted infected post-mating by its respective strain (Cfv and Cfvi). Semen samples collected from each bull at days 39, 82, 132 and 269 resulted positive for C. fetus by bacteriological culture and/or direct immunofluorescence (DIF) test, and confirmed by polymerase chain reaction (PCR) from colonies isolated. Diagnosis resulted better with bacteriological culture (100%) compared to DIF (37,5%). Campylobacter fetus was isolated from seminal vesicle and preputial mucosa by bacteriological culture and confirmed by PCR and DIF test from colonies previously isolated from these tissues (day 276). Microscopic lesions detected in both bulls showed moderate diffuse subepithelial lymphoplasmacytic postitis. None of the seminal vesicle presented relevant microscopic lesions. To our knowledge this is the first report of isolation of C. fetus from seminal vesicles in a bull. The experimental model herein described, mimicks the natural infection and constitutes a promising alternative for future studies of campylobacteriosis in cattle.

Diagnosis of Bovine Genital Campylobacteriosis in South America

Bovine genital campylobacteriosis (BGC) is a venereal infectious disease that affects reproduction. It is caused by the Gram-negative bacillus Campylobacter fetus subspecies venerealis (Cfv), which may include the biotype intermedius. The bull is a lifelong asymptomatic carrier and transmitter of the disease. In females Cfv may cause infertility and sporadic abortion. The objective of this study is to review and discuss methods for the diagnosis of BGC, its prevalence and economic impact in South America. BGC is a worldwide distributed disease and can cause a pregnancy rate decrease of 15-25%. The farm prevalence of BGC in different regions of South American countries shows a variation between 2.3 and 100%. Discrepancies may depend on the differences on sanitary, management, and reproductive practices between farms and regions, but also on the interpretation of different diagnostic tests. Currently known laboratory tests include bacterial culture, direct immunofluorescence, immunoenzymatic assays, vaginal mucus agglutination test, PCR-based methods, histology and immunohistochemistry, which are applied and interpreted in diagnostic laboratories at different scales. Epidemiologic data of BGC in South America should be interpreted with caution. High prevalence has been reported in some studies, although the low specificity of the diagnostic tests used could lead to an overestimation of the results.

Time series analysis of bovine venereal diseases in La Pampa, Argentina

The venereal diseases bovine trichomoniasis (BT) and bovine genital campylobacteriosis (BGC) cause economic losses in endemic areas like La Pampa province in Argentina where beef cattle are usually extensively managed. This study used data compiled between 2007 and 2014 by a Provincial Program for the Control and Eradication of venereal diseases in order to develop and analyze retrospective models of time series for BT and BGC. Seasonality and long-term trend were explored with decomposition and simple regression methods. Autoregressive Integrated Moving Average models (ARIMA) were used to fit univariate models for the prevalence and persistence of BT and BGC. Autoregressive Integrated Moving Average with Explanatory Variable models (ARIMAX) were used to analyze the association between different time series, replacement entries and herd samplings. The prevalence and persistence of BT and BGC have decreased from 2007 to 2014. All the BT and BGC time series are seasonal and their long-term trend is decreasing. Seasonality of BT and BGC is similar, with higher rates of detection in autumn-winter than is spring-summer. Prevalence and persistence time series are correlated, indicating their changes are synchronic and follow a similar time pattern. Prevalence of BT and BGC showed the best fitting with the ARIMA (0,0,1)(0,1,1)12 model. While for persistence of BT and BGC, the best adjustment was with the same model with no seasonal difference where the current number of cases depends on the moving averages of the month and the previous season. Including covariates improve the fitting of univariate models, in addition, estimations using ARIMAX models are more precise than using ARIMA models. The time distribution of the samplings could be increasing the false negative ratio. According to the obtained results, the ARIMA and ARIMAX models can be considered an option to predict the BT and BGC prevalence and persistence in La Pampa (Argentina).