Investigations on thegravis, mitisand intermediate types ofC. diphtheriæeand their clinical significance

Types of C. Diphtheriae in Capetown

“…Only a small percentage failed to fall into these groups.. Other workers have found aberrant strains ranging from 1.5 per cent. in Manchester (Robinson and Marshall, 1934) to 31.5 per cent. in Staffordshire (Menton, Cooper, Duke, and Fussell, 1933).…”

The Types Mitis, Intermedius and Gravis of Corynebacterium Diphtheriae

“…The statement under 6 in respect of differentiation between mitis and intermedius is founded on the unanimous findings of many observers (22, 69,144,149,195,207). This is so generally recognised that Pesch (138) claimed the development of hemolytic activity in intermedius strains subjected to repeated subculture in broth as evidence of their mutation to mitis.…”

“…Results in guinea-pigs and in a few instances in rabbits; subcutaneous and intracutaneous injection. A general impression of the relative pathogenicity of the different types may be taken from the combined results obtained in Australia, China, England, Germany, Italy, Poland, Russia and the Ukraine (22,35,55,56,58,65,89,104,106,128,137,149,152,169,184,185,192,194,207,211). Atypical strains: 97 examined, 53.6 per cent found virulent.…”

“…In such a case the rising mortality in some areas would be partly balanced by falling mortality in others, and an epidemic plateau would be produced as in Berlin in 1927-28-29 instead of a sharp epidemic spike as in Leeds, Hull or Dundee. However that may be and in spite of a higher case mortality rate for intermedius than for gravis in a number of areas (Liverpool, Romford and Manchester, in 1933), no record has yet been obtained of an area in which intermedius has been the predominant strain during a period of epidemic incidence of diphtheria or of high death rate per 100,000 of population (18,24,34,58,63,76,90,115,149). In those instances in which figures for death rate per 100,000 in the areas concerned at the time of observation are available, they vary from 14 in Glasgow in 1934 to 3 in Dundee in 1934 and Edinburgh in 1935.…”