Name the causative agent of 'typhoid'.

The causative agent of typhoid is the bacterium Salmonella Typhi.

Typhoid fever is a systemic infection caused by this Gram-negative, facultatively anaerobic, rod-shaped bacterium. It primarily affects the small intestine and can lead to severe complications if untreated. Transmission occurs through ingestion of contaminated food or water, often due to poor sanitation and hygiene practices. The bacterium invades the intestinal lining, enters the bloodstream, and spreads to various organs, including the liver, spleen, and bone marrow. Diagnosis is typically confirmed through blood or bone marrow cultures, while treatment involves antibiotics such as fluoroquinolones or third-generation cephalosporins. Prevention includes safe drinking water, proper sanitation, and vaccination.