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