ABSTRACT
Lyme disease (LD), caused by infection with Borrelia burgdorferi, is the most common tick-borne infection in many regions of Eurasia. Antibody detection is the most frequently used laboratory test, favoring a two-step serodiagnostic algorithm; immunoenzymatic detection of antibodies to C6 has been shown to perform similarly to a standard two-step workflow. The aim of this study was the performance evaluation of the C6 Lyme ELISA kit compared to a standard two-step algorithm in three laboratories located in the northeastern region of Italy which cater to areas with different LD epidemiology. A total of 804 samples were tested, of which 695 gave concordant results between C6 testing and routine workflow (564 negative, 131 positive). Wherever available, clinical presentation and additional laboratory tests were analyzed to solve discrepancies. The C6 based method showed a good concordance with the standard two-step algorithm (Cohen's κ = 0.619), however, the distribution of discrepancies seems to point towards a slightly lower specificity of C6 testing, which is supported by literature and could impact on patient management. The C6 ELISA, therefore, is not an ideal stand-alone test; however, if integrated into a two-step algorithm, it might play a part in achieving a sensitive, specific laboratory diagnosis of LD.
ABSTRACT
In 2005 the Autonomous Province of Bolzano implemented a BVD-Virus control programme by testing all newborn calves for Bovine Viral Diarrhoea Virus (BVDV) antigen by analysing ear notch samples. In eradication programs between November 2005 and October 2010 a total of 344,108 newborn calves were ear notch sampled and analysed for BVDV by an antigen ELISA detecting the E(rns) (HerdCheck BVDV Antigen/Serum Plus, Idexx Laboratories, Switzerland). The tissue samples were collected during calf ear tagging (within the first 20 days of life) using two sampling devices (TypiFix-System, Agrobiogen GmbH [Germany] and Allflex [France]). 0.4% (1400) of the collected samples showed a positive result, and of these, 583 calves were subjected to a follow-up examination, analysing the samples again by ELISA as well blood samples by Reverse transcriptase-PCR. Blood samples were also collected from the dam, if still present on the farm by the time of sampling. These results suggest that a BVDV control programme testing all newborn calves sampled for BVDV antigen by analysing an ear notch sample in principle is practicable. However, due to the low positive predictive value (75%) of the E(rns)-ELISA used, not all persistently infected calves can be detected.
