ABSTRACT
Leptospira serovar Hardjo are bacterial pathogens of cattle that cause zoonotic infections of humans. Monovalent serovar Hardjo vaccines protect cattle from serovar Hardjo while pentavalent vaccines do not even though they contain serovar Hardjo organisms. Here, cattle vaccinated with either of two monovalent vaccines had lymphocytes that made interferon-gamma (IFN-gamma) and IgG(1) and IgG(2) antibodies to Hardjo antigen while those from cattle vaccinated with a pentavalent Leptospira vaccine did not. IFN-gamma-producing cells were mainly CD4(+), but included CD8(+) and gamma delta TCR(+) cells. Despite their monovalent composition, those vaccines also induced IFN-gamma responses to serovar Grippotyphosa antigens. Thus, induction of a type 1 immune response is consistent with protective immunity to serovar Hardjo infections.
Subject(s)
Antibodies, Bacterial/biosynthesis , Bacterial Vaccines/immunology , Cattle Diseases/immunology , Leptospira/immunology , Leptospirosis/immunology , Leptospirosis/veterinary , Animals , Cattle , Cattle Diseases/prevention & control , Cell Division/drug effects , Cytokines/biosynthesis , Female , Flow Cytometry , Immunity, Cellular/immunology , Interferon-gamma/analysis , Interferon-gamma/biosynthesis , Leptospirosis/prevention & control , Monocytes/immunologyABSTRACT
Two microbiological procedures were evaluated to detect antibiotic residues in dairy cows at slaughter. Inhibition of Bacillus subtilis growth was used for determining the presence or absence of antibiotic residues. The two tests differed only in the concentration of B. subtilis used. The Swab Test on Premises (STOP) was used to detect antibiotic residues in kidney and muscle tissue and the Live Animal Swab Test (LAST) was used to detect residues in urine of cull dairy cows. Kidney samples from 3% of cull dairy cows were positive. Confirmation by standard reference procedures and a subsequent investigation on antibiotic residues in urine from 317 cows and heifers with known antibiotic treatment histories suggest that a high percentage of false-positive readings occurred in urine. In addition, 23 % of urine samples were difficult to interpret in that B. subtilis growth surrounding Swabs dipped in urine was reduced. While producer response was generally favorable for an on-farm screening test for antibiotic residues detection in cows going to slaughter, interpretation problems, difficulty in collecting urine samples, and concerns over the complexity and sensitivity make it unlikely that the acceptance of the LAST will be widespread on dairy farms.
