Diphtheria

Excerpt

Corynebacterium diphtheriae, a nonencapsulated, nonmotile, aerobic gram-positive bacillus, is the bacterium responsible for causing diphtheria. The primary risk factor for contracting this disease is the absence of immunization. While individuals may carry the bacterium asymptomatically, it often impacts the respiratory and integumentary systems. Humans serve as the exclusive hosts for this organism, which resides in the upper respiratory tract, and transmission of the bacteria occurs through airborne droplets.

The infection tends to be more prevalent during the spring or winter months. Without antibiotic intervention, its communicability persists for 2 to 6 weeks. Those with diminished antitoxin antibody levels or incomplete immunization are particularly susceptible to infection and may contract the illness upon exposure to a carrier or an individual already afflicted. In this context, a carrier refers to an asymptomatic individual whose cultures test positive for C diphtheriae. As the number of carriers decreases, there is a corresponding decline in the disease occurrence among the population.

The organism's pathogenicity hinges on the production of exotoxins, which can lead to severe complications, primarily affecting the heart muscle and nervous system. Timely diagnosis plays a pivotal role in achieving favorable clinical outcomes, as initiating antitoxin therapy and appropriate antibiotics early on can significantly impact patient prognosis.

Although the disease is more prevalent in tropical regions, it is a global concern. Patients typically present with a distinctive thick, gray, and adherent pseudomembrane on the tonsils and throats. Diagnosis involves isolating the organism, culturing it, and monitoring toxin production. Management includes patient isolation and the administration of antitoxin and antibiotics.

In prevention, vaccination against diphtheria is incorporated into the routine vaccination schedule as part of the combination diphtheria, tetanus toxoid, and acellular pertussis vaccine (DTaP). The adoption of DTaP in the US has remarkably diminished the occurrence of diphtheria. As acquired immunity naturally wanes with time, a booster is recommended to sustain protection. While vaccination does not provide a guarantee against diphtheria, individuals who have received the vaccine tend to experience less severe and fewer fatal diphtheria infections.