Diagnosis of bovine venereal campylobacteriosis by ELISA

Abstract

An enzyme-linked immunosorbent assay (ELISA) measuring IgA antibodies in the vaginal mucus was used to diagnose bovine venereal campylobacteriosis in 241 herds with infertility and abortions. The presence of the disease was confirmed on 84 farms (34.8%) and it was suspected on a further 27 farms (11.2%). The specificity of the ELISA was found to be 98.5% but in the absence of a reliable comparative test sensitivity can not be estimated. Vaccination against campylobacteriosis will not interfere with the IgA ELISA because only IgG is present in the vaginal mucus of vaccinates. Because of the possibility of false reactions caused by antibody fluctuations in individual cattle, the ELISA is best used as a herd test. It appears that at present the vaginal mucus IgA ELISA is the test of choice for the diagnosis of bovine venereal campylobacteriosis.

The use of enzyme-linked immunosorbent assay and immunoblotting for the detection of Campylobacter fetus immunoglobulins in the cervico-vaginal mucus of female cattle

“…The results obtained as previously described (Hewson 1985, Hum et al 1991, Hum et al 1994, McFadden et al 2005) cannot be fully compared to the results obtained in the present study. In the assay standardized by Hewson (1985) and Cobo et al (2003) a sonicated antigen was used, measuring the IgG-mediated local response, whereas Hum et al (1991) and McFadden et al (2005) used a crude antigen, which is considered less specific than the semi-purified antigens (Hirschl & Rotter 1990), such as the antigen preparation by acid extraction used in this study.…”

“…McFadden et al (2005) performing a screening for campilobacteriosis in 125 beef cow herds in New Zealand established a cutoff for positive result of 33EV (Elisa value), determinated as the sum of the mean EV of the negative controls plus three standard deviations, the same adopted by Hum et al (1994). The results obtained as previously described (Hewson 1985, Hum et al 1991, Hum et al 1994, McFadden et al 2005) cannot be fully compared to the results obtained in the present study.…”

“…Although they were not under the risk of a C. fetus infection, the mean OD 450 measurements obtained by IgA ELISA was 0.143, with a standard deviation of 0.09, indicating the occurrence of a substantial amplitude in optical density measurements. Data presented by Hum et al (1994) also showed a considerable amplitude of OD 450 values, with 10 EV with a standard deviation of 15 EV in the values detected by IgA ELISA.…”

“…The importance of IgA in the local immune response to C. fetus subsp. venerealis was discussed for naturally infected females, females that aborted, and those that only maintained persistent infection by Wilkie et al (1972), Corbeil et al (1975), Winter (1982), Hum et al (1991Hum et al ( , 1994.…”

“…Another cutoff was later established by the same authors, being higher due to the use of three standard deviations, aiming at achieving higher test specificity for the diagnosis of C. fetus subsp. venerealis female carriers in herds (Hum et al 1994).…”