802 HEMOPHILUS 



haemolysis on Bordet-Gengou medium, in growing more profusely and developing a brownish 

 pigment on nutrient agar, and in producing a large amount of catalase. The strains 

 isolated were antigenicaUy homogeneous, and cross-agglutinated with Phase I H. pertussis 

 and H. bronchisepticus. Like H. pertussis, the organism was serologically characterized 

 by a readily extractable, non-toxic and stable agglutinogen, having a minor antigenic 

 component in common with H. pertussis (Flosdorf, Bondi and Dozois 1941, Bondi and 

 Flosdorf 1943). This organism is now generally known as H. parapertussis. 



The antigenic relationship of the agglutinogens of these three organisms is paralleled 

 to some extent by an antigenic relationship of their toxins (see below). There are cultural 

 resemblances between the three, and all are associated with infections of the lung in the 

 higher mammals. These facts justify the provisional inclusion of Br. bronchiseptica in 

 the group containing H. pertussis, and we have accordingly implemented the suggestion 

 of Eldering and Kendrick and of Evans and Maitland (1939), and renamed Br. bronchi- 

 septica, H. bronchisepticus (see also Watanabe 1938). 



It is clear that, as far as whooping cough is concerned, any bacillary material used 

 for whooping cough inoculation must be derived from organisms in Phase I, so treated 

 that the very soluble agglutinogen is not removed during the preparation of the vaccine ; 

 it may also be necessary to include in the vaccine the major antigens of H. parapertussis. 



Finally, we may note that such comparative tests as have been performed show 

 little if any antigenic relationship between H. pertussis and H. influenzce (Odaira 1911, 

 Shiga et al. 1913, Winholt 1915, Ohnstead and Povitsky 1916, Kristensen 1922, Schliiter 

 1936). 



Pathogenicity and Toxin Production. 



The probable role of H. influenzce in human influenza, which is now known to 

 be a virus disease, is considered in Chapter 74, It is a common cause of sinusitis, 

 alone or in association with the pneumococcus, an occasional cause of meningitis, 

 almost always in children, and a rare cause of ulcerative endocarditis. The Koch- 

 Weeks bacillus has been isolated from epidemics of conjunctivitis in many parts 

 of the world, children being mainly infected. As, however, there is no known 

 method by which this organism can be distinguished from H. influenzcB, it 

 seems unnecessary to regard it as a different species. 



H. jtara-influenzcB is occasionally associated with acute pharyngitis ; it is a 

 rare cause of ulcerative endocarditis, though probably less rare than H. influenzce 

 itself (Miles and Gray 1938), and it is occasionally found in infected wounds and 

 sinuses. 



There appears to be little doubt that H. ducreyi is responsible for soft chancre, 

 and for the buboes which are sometimes associated with the primary lesion. 



H. bronchisepticus is essentially parasitic, giving rise to lesions in the respiratory 

 tract of dogs, monkeys, guinea-pigs and other laboratory animals : it is occa- 

 sionally found in the nasopharynx of man. It appears to be a secondary invader 

 in dogs suffering from distemper, being frequently responsible for the pulmonary 

 complications of the disease (M'Gowan 1911, Laidlaw and Dunkin 1926). Spooner 

 (1938) found it playing a similar role in a spontaneous distemper-like disease 

 of ferrets. 



H. pertussis is the cause of whooping cough, and as such is one of the more 

 important human pathogens. H. parapertussis appears to be responsible for 

 a minority of cases of whooping cough. Unlike H. influenzce, H. pertussis seems 

 seldom to play a harmless parasitic role. 



Both H. pertussis and H. bronchisepticus elaborate at least one toxin. H. per- 

 tussis toxin was first described by Evans and Maitland (1937), who extracted it 



