Final answer:
The most likely bug causing diarrhea followed by areflexia and ascending paralysis is Campylobacter jejuni, potentially leading to Guillain-Barré syndrome. Treatment involves immunoglobulins or plasma exchange and supportive care.
Step-by-step explanation:
The symptoms described in the question, such as diarrhea followed by areflexia and ascending paralysis, are indicative of an infection that might have led to a condition known as Guillain-Barré syndrome (GBS). The most likely causative agent in this scenario, given the association with gastrointestinal symptoms and subsequent development of neurological signs, is the bacterium Campylobacter jejuni. GBS is an autoimmune disorder that affects the peripheral nervous system, typically triggered by an infection.
Treatment for Guillain-Barré syndrome often begins with interventions such as intravenous immunoglobulins (IVIG) or plasma exchange (plasmapheresis) to reduce the severity and duration of the paralysis. Supportive care, which may include mechanical ventilation if breathing is affected, is also crucial. Early treatment is important to prevent complications and improve outcomes.