How does a prolonged excessively high blood temperature during an illness could be fatal to human?

Prolonged excessively high blood temperature, or hyperthermia, can lead to severe physiological stress, causing cellular damage and disrupting normal metabolic processes. It can impair the function of vital organs, such as the brain and heart, potentially resulting in organ failure. Additionally, sustained high temperatures can lead to heatstroke, which can be fatal if not promptly treated, as it affects the body's ability to regulate temperature and maintain homeostasis. Ultimately, if the body cannot cool itself down, the risk of serious complications and death increases significantly.