Lymphocyte proliferation assays are widely used to assess the cell-mediated immunity. Current in vitro testing methods that are being used have extensive applications but still more problematic, due to the technical complexity and the needs for specialized equipment and reagents. Electrochemical methods such as cyclic voltammetry represent a very promising tool for the development of label-free in vitro assays of cell proliferation and viability. Here, a novel procedure based on voltammetric behaviours of proliferating cells was fabricated. Results indicated that proliferation in cell cultures and whole blood can be monitored electrochemically using cyclic voltammetry. In the comparison with colorimetric (MTT) assay, cyclic voltammetry gave the best correlation with cell count data over a range of 1200–300,000 cells/well of a microplate. Besides the advantages of short assay duration (4 hours) and the rapidness, the possibility use of fresh blood without further processing, would give more accurate results because cells are monitoring in an intact environment. Cyclic voltammetry assay is an efficient analytical method, which can provide a simple platform for the electrochemical study of lymphocyte proliferation.

Bovine viral diarrhoea virus (BVDV), bovine herpesvirus type 1 (BoHV1) and bovine leukaemia virus (BLV) are among the most important pathogens of dairy cattle which cause significant economic burden around the world. The aim of this study was to investigate seroprevalence and concurrent presence of antibodies against BVDV, BoHV1 and BLV in dairy cattle in Iran. A total of 882 animals were sampled and the presence of antibodies against BVDV, BoHV1 and BLV was determined by commercial Enzyme link immunosorbent assay (ELISA) kits. The overall BVDV, BoHV1 and BLV seroprevalence was 64.4%, 31.9% and 16.2%, respectively. The prevalence of antibodies against mentioned pathogens varied among different provinces studied. In addition, no correlation was observed between BLV seropositivity and either BVDV or BoHV1 seropositivity while there was a positive correlation between BVDV and BoHV1 seropositivity (P < 0.01). The results of the current study revealed that BVDV, BoHV1 and BLV infections are present in different regions of Iran and thus it seems necessary to implement control programmes to prevent further spread of mentioned pathogens. Moreover, it was demonstrated that a previous infection with either BVDV or BoHV1 might be a risk factor for future infection with BoHV1 or BVDV, respectively.

Immunocompetence of livestock plays an important role in farm profitability because it directly affects health maintenance. Genetics significantly in