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SUMMARY

We investigated the ability of an antibody-specific, O antigen-based elisa to document Salmonella typhimurium herd infections by screening of milk samples. Three cattle populations, 20 herds with no history of salmonellosis, 8 herds with history of S typhimurium epsiodes within the previous 7 months, and 220 herds of unknown disease status, were tested. A herd was considered elisa positive if at least 5% of the cows had OD values > 0.3. Among the 20 herds without history of salmonellosis, only 2 herds were elisa positive, whereas all 8 herds with a known history of salmonellosis were elisa positive (herd specificity, 0.9 and herd sensitivity, 1.0). A significant correlation (P < 0.001) was found between the OD values of serum and milk samples from cows in the herds with a history of salmonellosis. It was concluded that elisa testing of individual milk samples can be used for surveillance of herds for S typhimurium infections, but further modifications are needed to test bulk tank milk samples.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To compare muscle fluid with serum samples for detection of antibodies to Salmonella lipopolysaccharide.

Sample Population

Muscle fluid and serum samples from 2 cattle populations: 1 from the island of Bornholm with no history of salmonellosis (n = 39), and the other from the S dublin-enzootic areas of Jutland (n = 144).

Procedure

Salmonella dublin (O:1,9,12), S typhimu-rium (O:1,4,5,12), and Salmonella O:9-blocking ELISA were used for testing the samples.

Results

In the S dublin ELISA, all serum and muscle fluid samples from cattle on the island of Bornholm had OD450 values well below the cutoff value (0.5). For samples obtained from cattle in the enzootic areas of Jutland, high correlation was found between serum and muscle fluid samples (r s = 0.89, P < 0.001). In addition, 19% (28/144) of the cattle had ELISA-positive muscle fluid and serum samples; 2% (3/144) had positive results for muscle fluid only, whereas 1 animal had positive results for serum only (κ = 0.91, P < 0.0001; sensitivity and specificity of 97%). The same samples had similar significant correlation in the S typhimurium ELISA (r s = 0.88, P < 0.001, κ = 0.7, P < 0.001; sensitivity of 73% and specificity of 98%) and the O:9-blocking ELISA (r s = 0.49, P < 0.001).

Conclusion and Clinical Relevance

Muscle fluid samples taken at slaughter can be used as a practical alternative to serum samples for surveillance of Salmonella infections in cattle. (Am J Vet Res I997;58;334-337)

Free access
in American Journal of Veterinary Research