BIOS 350 Lecture Notes - Lecture 20: Pertussis, Diphtheria, Corynebacterium Diphtheriae
Document Summary
29. 1 airborne pathogens: aerosols are important for person-to-person transmission of many infectious diseases (figure 29. 1, most pathogens survive poorly in air; thus, they are effectively transmitted only over short distances. Respiratory infections: different pathogens characteristically colonize the respiratory tract at different levels (figure 29. 2) The upper and lower respiratory tracts offer different environments and favor different microbes. Streptococcus pyogenes (figure 29. 3: also called group a streptococci. Commonly found in low numbers in the upper respiratory tract of healthy individuals. Can also cause infections of the inner ear, mammary glands, and skin (figure. Erysipelas is an acute streptococcal skin infection (figure 29. 7) Infections occur if host defenses are weakened or a new, highly virulent strain is introduced. Certain group a streptococci strains carry a lysogenic bacteriophage that encodes exotoxins responsible for symptoms of toxic shock syndrome and scarlet fever (figure 29. 9: untreated or insufficiently treated infections can lead to other diseases (e. g. , rheumatic fever)
