20. Diptheria
Corynebacterium diphtheriae- aerobic gram +ve bacillus
exotoxin production only when c. diptheriae infected by virus carrying toxin gene
LYSOGENIC CONVERSION- nontoxigenic cell converted to toxigenic cell
source of infection
an infected case or a carrier
infected case can be mild or silent infections (runny nose)
95 carriers for every 5 cases
temporary carriers (1 month)
chronic carriers (1 year)
nasal or throat
nasal carriers more dangerous than throat due to frequent shedding of organism
clinical signs and symptoms
transmission
via droplets, infected cutaneous lesions, objects e.g. cups and toys, nasopharyngeal secretions
respiratory tract route
non resp route- cuts wounds and ulcers in skin, umbilicus in newborns, eye, middle ear, genitals,
incubation period 2-6 days
sore throat
low grade fever
adherent membrane forms of nose, tonsils, pharynx, uvula
neck swelling- severe
exotoxin can cause damage to heart muscle, kidneys, nerves (all have receptors for this toxin) paralysis
can come loose and obstruct breathing
upper respiratory tract infection
exotoxin in blood can kill cells by interfering with protein synthesis
prevention and treatment
immunisation with diphtheria toxoid
@ 6 weeks 4 months, 6m, 18m and 4-6 yrs
booster every 10 years
antitoxin treatment, erythromycin prevents transmission