Diphtheria: A Paradigmatic Vaccine-Preventable Toxigenic Disease with Changing Epidemiology

Abstract

Diphtheria is a paradigmatic example of a toxigenic infectious disease. It was Klebs who first identified Corynebacterium diphtheriae as the causative agent for diphtheria in 1883. It is an acute respiratory infection characterized by pseudo-membrane formation in the throat but can also cause cutaneous infections. Systemic effects are a result of the production of diphtheria toxin, which is an exotoxin that inhibits protein synthesis and leads to cell death. The toxin can commonly cause myocarditis and neuropathy, which are associated with increased mortality. Clinical diagnosis is of utmost importance and timely diagnosis and management are lifesaving. An attempt to confirm the diagnosis by isolating and identifying Corynebacterium diphtheriae by microbiological culture should be made. Enzymatic and toxin detection tests should confirm the isolate. Treatment consists of the administration of diphtheria antitoxin and antimicrobial therapy. Mainly a vaccine-preventable childhood disease, this disease has re-emerged in countries where the recommended vaccination programs are not sustained, and not only children but also adults are becoming prey to the disease. In the South East Asia region, thousands of diphtheria cases are reported annually. Globally, small pockets of outbreaks still occur in developed countries. There has been a change in the epidemiological trend of diphtheria around the world. In order to prevent the spread of such toxigenic strains in communities, clinical and epidemiological investigations are necessary along with strict public health measures. Recent outbreaks have highlighted the importance of vaccination in reducing the incidence in children and its re-emergence in adults.