whooping cough pertussi
Whooping cough is an acute respiratory illness that primarily affects infants and young children. The etiologic agent is usually Bordello pertussis; occasionally B. para pertussis, and rarely B. bronchitis produces a similar syndrome. The descriptive name derives from a distressing, prolonged inspiratory effort that follows paroxysmal coughing. Although both more-morbidity and mortality have markedly declined, whooping cough is still responsible for a significant number of deaths in infants. History.
The disease was first recorded in the middle of the sixteenth century by Moulton and by Debouillet. Whether whoopING cough was indigenous to Europe or had been transported there in the preceding century is uncertain. Menhaden applied the name “pertussis” to any illness accompanied by violent coughing, but the term became restricted to the epidemic dis-ease that was a well-recognized clinical entity by, the middle of the eighteenth century. In 1900 Borden and Gouge observed Lactobacillus in the sputum of a child with whooping cough, but it was not until 1906 that they were able to culture the organism. Many years passed before the Borden-Gouge bacillus was universally accepted as the etiologic agent of whooping cough.
Leslie and Gardner (1931) recognized that B. pertussis underwent marked biologic and morphological changes on prolonged cultivation, thereby accounting for the difficulties in establishing the etiologic role of the agent and the inconstant protective effect of immunizing preparations. Although the mortality rate of whooping cough in the United States began to decline in the early part of this century, the incidence in young children did not significantly decrease until after the use of prophylactic vaccines became widespread 25 years ago. Etiology. When first isolated, Bordello pertussis is a minute, nonmotile, poorly staining, gram-negative Lactobacillus, 0.5 Au. to 1.0 g in length. Capsules can be demonstrated by special procedures, and bipolar metachromatic granules are present.
The complex medium containing blood originally employed by Borden and Gouge is still often used for cultivation. Primary isolates, phase I organisms, v3i11 not; JIM en conventional laboratory media, but will do so after prolonged passage. At the same time, colonial morphology changes marked isomorphism of individual cells is evident, and there is an alteration in anti-genie composition. The change from phase I to phase IV has been likened to the smooth to the rough transition of other microbes. The only phase I organ-isms is virulent, and the only phase I organisms provide effective immunizing material.
Members of the Bordello genus were formerly regarded as species of Haemophiliacs. However, the Bordello group does not have strict requirements for X and V growth factors, and they are antigenically distinct. Although the addition of blood to Bordet-Gengou medium is required for the growth of phase I organisms, the blood acts to neutralize bactericidal substances, probably fatty acids, rather than to provide nutrients. Media containing charcoal, starch, or ion exchange re-sins will support the growth of phase I bacteria.B. pertussis produces a heat-stable toxin (endotoxin) and a heat-labile toxin. The role of toxins in the development of disease has not been demonstrated. A hemagglutinin has also been isolated.
The capsular material does not swell in the presence of antiserum. A species agglutinogen has been recognized as well as agglutinating factors that differ between strains. Serotyping is there-fore a useful epidemiological tool. The role of the interaction between the organism and phagocytes has not been defined, although the presence of antisera appears to increase uptake of B. pertussis by leukocytes.