Development of a multiplex fluorescence immunological assay for the simultaneous detection of antibodies against Cooperia oncophora, Dictyocaulus viviparus and Fasciola hepatica in cattle.

BACKGROUND: A major constraint for the effective control and management of helminth parasites is the lack of rapid, high-throughput, routine diagnostic tests to assess the health status of individual animals and herds and to identify the parasite species responsible for these helminthoses. The capability of a multiplex platform for the simultaneous detection of three pasture associated parasite species was evaluated and compared to existing ELISAs. METHODS: The recombinant antigens 14.2 kDa ES protein for Cooperia oncophora, major sperm protein for Dictyocaulus viviparus and Cathepsin L1 for Fasciola hepatica were recombinantly expressed either in Escherichia coli or Pichia pastoris. Antigens were covalently coupled onto magnetic beads. Optimal concentrations for coupling were determined following the examination of serum samples collected from experimentally mono-infected animals, before and after their infection with the target species. Absence of cross-reactivity was further determined with sera from calves mono-infected with Haemonchus contortus, Ostertagia ostertagi and Trichostrongylus colubriformis. Examination of negative serum samples was characterised by low median fluorescence intensity (MFI). RESULTS: Establishment of the optimal serum dilution of 1:200 was achieved for all three bead sets. Receiver Operating Characteristic analyses were performed to obtain cut-off MFI values for each parasite separately. Sensitivity and specificity at the chosen cut-off values were close to, or 100% for all bead sets. Examination of serum samples collected on different days post infection from different animals showed a high reproducibility of the assays. Serum samples were additionally examined with two already established ELISAs, an in-house ELISA using the recombinant MSP as an antigen and a DRG ELISA using Cathepsin L1 for liver fluke. The results between the assays were compared and kappa tests revealed an overall good agreement. CONCLUSIONS: A versatile bead-based assay using fluorescence detection (xMAP technology) was developed to simultaneously detect antibodies against C. oncophora, D. viviparus and F. hepatica in cattle serum samples. This platform provides rapid, high-throughput results and is highly sensitive and specific in comparison to existing serological as well as coproscopical diagnostic techniques.

Epidemiological Observations on Cryptosporidiosis in Diarrheic Goat Kids in Greece.

This study aimed at investigating the occurrence of Cryptosporidium spp. in diarrheic goat kids in Greece and the risk factors associated with cryptosporidiosis. Altogether, 292 diarrheic 4-15-day-old goat kids from 54 dairy goat herds of Northern Greece were examined. Oocysts of Cryptosporidium spp. were detected in 223 of 292 (76.4%) goat kids and the intensity of infection was scored as "high" in 142 samples, "moderate" in 45 samples, and "low" in 36 samples. Larger herds (>200 animals) had higher infection rates than smaller ones, although this difference was not statistically significant. Significantly higher infection rates were observed in herds during late kidding season (1 January to 30 April) compared to the early one (1 September to 31 December). These results suggest that cryptosporidiosis is very common in diarrheic goat kids in Greece, especially in large herds during the late parturition season.