Type C foodborne botulism: First clinical case report of a cluster within a family in Japan

Foodborne botulism is a rare but potentially fatal neuroparalytic disease caused by the ingestion of food contaminated with Clostridium botulinum . Early diagnosis is challenging because its symptoms mimic those of other neuroparalytic diseases, such as Guillain–Barré and Miller–Fisher syndromes. Laboratory confirmation of botulinum toxin and antitoxin procurement can take several days. Type C botulism is extremely rare in humans, with only 15 reported cases worldwide. Members of a family consumed expired, improperly stored, vacuum-packed chicken dishes. Four members (two adults and two children) ingested the food. The adults developed blurred vision, dysarthria, limb weakness, and respiratory distress within 24 h. Foodborne botulism was suspected based on a family cluster and shared meal history. Both adults required intubation and received antitoxins within 3 days. Following prolonged mechanical ventilation, the patients gradually improved and were discharged for rehabilitation after 2 months. The children, who were initially asymptomatic, received prophylactic antitoxins. Both children developed mild gastrointestinal symptoms and transient weakness and recovered fully within 10 days. Laboratory testing confirmed the presence of type C botulinum toxin in three patients. This report describes the first documented cluster of human type C foodborne botulism cases in Japan. Although rare in humans, type C toxin can cause severe acute neuroparalytic syndrome when contaminated food is stored improperly. The early recognition of family clustering and prompt procurement of antitoxins are essential for effective management. • Type C botulinum toxin, though rarely reported in humans, can cause severe foodborne botulism alongside types A, B, and E. • Even processed foods that are processed under safe conditions, such as vacuum-packed or retort products, can become a source of botulism if stored improperly. • Botulinum antitoxin is ideally administered within 48 hours of symptom onset. Because diagnostic confirmation and drug procurement often take several days, preparation should begin as soon as botulism is clinically suspected.