Short answers, pulled from the story.
Typhoid fever is caused by the bacterium Salmonella enterica subsp. enterica serovar Typhi which grows inside human intestines. This specific strain infects only people with no known animal reservoir existing for this pathogen.
Untreated typhoid fever progresses through three distinct stages each lasting about one week where patients become exhausted and emaciated. The first week features rising body temperature and relative bradycardia while the second week shows high fever plateaus around 40 degrees Celsius and delirium. Complications in the third week include intestinal hemorrhage from bleeding in congested Peyer's patches and intestinal perforation in the distal ileum.
Maidstone England became the first town to chlorinate its entire water supply following an outbreak in 1897. That same year recorded 1,847 patients with typhoid fever before the intervention took effect.
Two licensed vaccines exist today including live oral Ty21a sold as Vivotif and injectable polysaccharide vaccine sold as Typhim Vi. Protection may last up to seven years depending on the formulation with boosters recommended every five years for the oral version and every two years for injections.
Resistance to ampicillin chloramphenicol trimethoprim-sulfamethoxazole and streptomycin has become common globally so these agents are no longer used as first-line treatment. Multidrug-resistant typhoid strains have evolved rapidly since the 1950s when resistance to chloramphenicol became frequent in Southeast Asia.