IV. INVESTIGATION OF C. DIPHTHERIAE
63
and therapeutic agents. There are, however, many convincing arguments
which support the investigation and control of diphtheria as a mass
infection.
The high levels of specific immunity acquired through the vast immunisation programmes have on the one hand deeply modified the biological properties of the causative agent, and on the other have brought
about many atypical forms of diphtheria ; the clinical and bacteriological
diagnosis thus present marked difficulties for the young practitioner who
has not himself had the opportunity to see classical diphtheria.
Due to the fact that the number of isolated organisms in a wellimmunised community is decreasing, the waning interest in this disease
usually contributes to an increasing number of non-immunised or partially
immunised individuals in the community.
Under these circumstances a recurrence of sporadic cases of the disease
or even long-lasting outbreaks occurring in different parts of the world, is
important. In the U.S.A., for instance, before the introduction of mass
immunisation programmes, more than 10 000 cases, were reported annually.
Since 1952 a marked drop in the morbidity of diphtheria has been observed.
However, 50 years after the introduction of diphtheria toxoid, substantial segments of the United States population are still not immunised
against diphtheria, and large, sporadic diphtheria outbreaks still occur
(Marcuse et al., 1973; Zalma et al., 1970; McCloskey et al., 1972).
General experience also shows that occasional outbreaks may still occur
everywhere, suggesting that the organism exists in endemically diverse
forms, and when conditions are appropriate, these may initiate either
typical or atypical infections of the upper respiratory tract or cutaneous
infections (Wilson and Toshach, 1957; Belsey et al., 1969).
Cutaneous diphtheria and skin carriage frequent in native populations of
tropical countries represent a possible connection between epidemics.
All these’facts, the intense tourist traffic throughout the world, as well as the
pathogenicity of diphtherial toxaemia which calls for a rapid clinical and
microbiological diagnosis, explain the present interest for practical and
standardised methods in controlling diphtheria.
11. MICROBIOLOGICAL CHARACTERS OF
COR YNEBACTERIUM DIPHTHERIAE
A. Definition of the genus Corynebacteriurn and of the type
species Corynebactherium diphtheriae
“Bergey’s Manual of Determinative Bacteriology” (Bergey, 1974) defined
Straight to slightly curved rods with irregularly stained segments, and
this group of micro-organisms.
63
and therapeutic agents. There are, however, many convincing arguments
which support the investigation and control of diphtheria as a mass
infection.
The high levels of specific immunity acquired through the vast immunisation programmes have on the one hand deeply modified the biological properties of the causative agent, and on the other have brought
about many atypical forms of diphtheria ; the clinical and bacteriological
diagnosis thus present marked difficulties for the young practitioner who
has not himself had the opportunity to see classical diphtheria.
Due to the fact that the number of isolated organisms in a wellimmunised community is decreasing, the waning interest in this disease
usually contributes to an increasing number of non-immunised or partially
immunised individuals in the community.
Under these circumstances a recurrence of sporadic cases of the disease
or even long-lasting outbreaks occurring in different parts of the world, is
important. In the U.S.A., for instance, before the introduction of mass
immunisation programmes, more than 10 000 cases, were reported annually.
Since 1952 a marked drop in the morbidity of diphtheria has been observed.
However, 50 years after the introduction of diphtheria toxoid, substantial segments of the United States population are still not immunised
against diphtheria, and large, sporadic diphtheria outbreaks still occur
(Marcuse et al., 1973; Zalma et al., 1970; McCloskey et al., 1972).
General experience also shows that occasional outbreaks may still occur
everywhere, suggesting that the organism exists in endemically diverse
forms, and when conditions are appropriate, these may initiate either
typical or atypical infections of the upper respiratory tract or cutaneous
infections (Wilson and Toshach, 1957; Belsey et al., 1969).
Cutaneous diphtheria and skin carriage frequent in native populations of
tropical countries represent a possible connection between epidemics.
All these’facts, the intense tourist traffic throughout the world, as well as the
pathogenicity of diphtherial toxaemia which calls for a rapid clinical and
microbiological diagnosis, explain the present interest for practical and
standardised methods in controlling diphtheria.
11. MICROBIOLOGICAL CHARACTERS OF
COR YNEBACTERIUM DIPHTHERIAE
A. Definition of the genus Corynebacteriurn and of the type
species Corynebactherium diphtheriae
“Bergey’s Manual of Determinative Bacteriology” (Bergey, 1974) defined
Straight to slightly curved rods with irregularly stained segments, and
this group of micro-organisms.