Corynebacterium diphtheriae • Aerobic gram-positive bacillus • Toxin production occurs only when C. diphtheriae infected by virus (phage) carrying tox gene • If isolated, must be distinguished from normal diphtheroid • Toxoid developed in 1920s Diphtheria Clinical Features • Incubation period 2-5 days (range, 1-10 days) • May involve any mucous membrane • Classified based on site of infection –anterior nasal –pharyngeal and tonsillar –laryngeal –cutaneous –ocular –genital
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Corynebacterium diphtheriae Diphtheria Clinical Features
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Corynebacterium diphtheriae
• Aerobic gram-positive bacillus
• Toxin production occurs onlywhen C. diphtheriae infected byvirus (phage) carrying tox gene
• If isolated, must be distinguishedfrom normal diphtheroid
• Toxoid developed in 1920s
Diphtheria Clinical Features
• Incubation period 2-5 days(range, 1-10 days)
• May involve any mucous membrane
• Classified based on site of infection–anterior nasal
–pharyngeal and tonsillar
–laryngeal
–cutaneous
–ocular
–genital
Pharyngeal and Tonsillar Diphtheria
• Insidious onset
• Exudate spreads within 2-3 daysand may form adherent membrane
• Membrane may cause respiratoryobstruction
• Pseudomembrane: fibrin, bacteria,and inflammatory cells, no lipid
• Fever usually not high but patientappears toxic
Diphtheria Complications
•Most attributable to toxin
• Severity generally related toextent of local disease
•Most common complicationsare myocarditis and neuritis
• Death occurs in 5%-10% forrespiratory disease
Diphtheria Antitoxin
• Produced in horses
• First used in the U.S. in 1891
• Used only for treatment ofdiphtheria
• Neutralizes only unbound toxin
• Lifetime of Ab: 15 days – 3weeks, wait 3-4 weeks beforegiving toxoid. Only given once.
Diphtheria Epidemiology
• Reservoir Human carriers Usually asymptomatic
• Transmission Respiratory, aerosols Skin lesions
• Temporal pattern Winter and spring
• Communicability Up to several weekswithout antibiotics
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1940 1950 1960 1970 1980 1990 2000
Cases
Diphtheria - United States,1940-2005
Year
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1980 1985 1990 1995 2000 2005
Cases
Diphtheria - United States,1980-2005
Year
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<5 5-14 15-24 25-39 40-64 65+
Age group (yrs)
Cases
Diphtheria – United States, 1980-2004Age Distribution of Reported Cases
N=53
Diphtheria Toxoid
• Formalin-inactivated diphtheria toxin
• Schedule Three or four doses + booster Booster every 10 years
• Efficacy Approximately 95%
• Duration Approximately 10 years
• Should be administered with tetanustoxoid as DTaP, DT, Td, or Tdap
Dose
Primary 1
Primary 2
Primary 3
Primary 4
Age
2 months
4 months
6 months
15-18 months
Routine DTaP PrimaryVaccination Schedule
4-6 yrs
11-12 yrs
Every 10 yrs
Diphtheria and Tetanus ToxoidsAdverse Reactions
• Local reactions (erythema,induration)
• Exaggerated local reactions(Arthus-type)
• Fever and systemic symptomsnot common
• Severe systemic reactions rare
Diphtheria and Tetanus ToxoidsContraindications and Precautions
• Severe allergic reaction tovaccine component or followinga prior dose
•Moderate or severe acute illness
Tetanus
• First described by Hippocrates
• Etiology discovered in 1884 byCarle and Rattone
• Passive immunization used fortreatment and prophylaxisduring World War I
• Tetanus toxoid first widely usedduring World War II
Clostridium tetani
• Anaerobic gram-positive, spore-forming bacteria
• Spores found in soil, animalfeces; may persist for months toyears