What is the primary complication of untreated streptococcal throat infection?

Untreated streptococcal throat infections, predominantly caused by Group A Streptococcus, can lead to a significant complication known as acute rheumatic fever. This condition is an inflammatory disease that can arise after infection, particularly if the throat infection is not adequately treated with antibiotics. Acute rheumatic fever can affect various systems in the body, particularly the heart, joints, skin, and the central nervous system.

The connection between streptococcal throat infections and acute rheumatic fever is based on an autoimmune response, where the body's immune system reacts to the streptococcal bacteria and mistakenly attacks its own tissues. This can result in severe manifestations, such as rheumatic heart disease, which may cause long-term damage to heart valves.

The other options presented do not directly relate to the complications typically associated with untreated streptococcal throat infections. Chronic bronchitis generally results from chronic irritation of the airways, commonly due to smoking or long-term exposure to irritants, and is not a sequel of streptococcal infections. Viral pneumonia is caused by viral agents, and while a secondary bacterial infection could occur after a viral illness, it is not a direct complication of streptococcal throat infections. Pneumococ