Mastitis: aspects of the host-pathogen interaction

Abstract

Mastitis, generally defined as the inflammation of the mammary gland, is the most costly of the infectious, endemic diseases to affect dairy cows and other dairy species. The greatest obstacle to reduce mastitis is the implementation of effective mastitis control measures in dairy farmers, which mainly depends on a better understanding of the complex interaction between an infecting pathogen and the host immune system. Host-pathogen interaction is a broad, important area of research encompassing both basic and clinical sciences. Thus, here it was addressed some aspects of the host-pathogen interactions, as follows: 1) Review of the role of pattern-recognition receptors in the innate immunity of bovine mastitis with focuses on the major mastitis pathogens: Escherichia coli and Staphylococcus aureus; 2) Determine a set of rules for classifying the infection status of an udder at quarter (single and duplicate milk samples) and cow (composite milk sample) levels and compare with distincts somatic cell count (SCC) thresholds (at quarter and cow levels); 3) Evaluation of the interdependence of the quarters by evaluating milk neutrophil function and milk lymphocyte profiles in uninfected quarters from infected and uninfected udders by flow cytometry analysis; 4) Function of milk neutrophils and the milk lymphocyte profile in Streptococcus dysgalactiae-infected mammary glands; 5) Capacity of S. aureus, S. fleurettii, and two dissimilar strains of S. chromogenes species to adhere and internalize into bovine mammary epithelial cells; 6) Efficacy of a commercial vaccine under field condition in two dairy herds with high bulk milk somatic cell count (SCC) and a high prevalence of IMIs by S. aureus.