Which type of anthrax is indicated by symptoms of fever, malaise, fatigue, and a nonproductive cough, along with a widened mediastinum in chest x-rays?

The symptoms described, including fever, malaise, fatigue, a nonproductive cough, and a widened mediastinum seen on chest x-rays, are indicative of inhalation anthrax. Inhalation anthrax results from the spores of the bacterium Bacillus anthracis being inhaled into the lungs, leading to a severe respiratory illness.

The early symptoms, such as fever and fatigue, can mimic those of a common viral infection, but the development of respiratory symptoms and particularly the widened mediastinum on imaging studies are key clinical indicators that differentiate inhalation anthrax from other forms of the disease. The widening of the mediastinum is often due to the presence of lymphadenopathy and can suggest a more severe form of the infection, reflecting the systemic nature of inhalation anthrax.

In contrast, cutaneous anthrax typically presents with a localized skin lesion, gastrointestinal anthrax often involves symptoms like nausea and abdominal pain due to ingestion, and injection anthrax presents with symptoms localized at the injection site. Thus, the clinical presentation of the symptoms and the diagnostic imaging findings strongly point to inhalation anthrax.