Diphtheria

Abstract

Diphtheria is a vaccine-preventable life-threatening disease. It is caused by toxins released by the bacteria Corynebacterium diphtheria, some strains of C. ulcerans, and very rarely C. pseudotuberculosis. The disease is caused by the local effects of destructive infection (usually in the nasopharynx) and the distal effects of diphtheria toxin on the heart, peripheral nerves, and kidneys. Death results from airways obstruction, myocarditis, or polyneuritis. Diphtheria has declined dramatically in wealthier countries over the past 80 years, but it remains an important disease in many parts of the tropics and there have been resurgences of the disease in some countries. Recently, there have been outbreaks in Yemen, Bangladesh, Venezuela, and Haiti associated with civil unrest, privation, forced migration, and disasters. C. diphtheriae infections result from person-to-person spread via respiratory droplets and close contact. C. ulcerans infections are usually acquired from raw milk and/or contact with farms and farm animals or close contact with companion animals and pets (cows, goats, cats, and dogs). Death can occur in up to 10% of clinical cases despite antibiotics and the use of antisera. Diphtheria is transmitted mainly by droplet spread. It is preventable by vaccination and the coverage in the population must be maintained above 95%.