Final answer:
The signs of Salmonella typhi, which causes typhoid fever, typically include high fever, body aches, headache, nausea, lethargy, and sometimes a rash, with severe cases leading to delirium and dehydration.
Step-by-step explanation:
Signs of Salmonella typhi, which causes typhoid fever, include high fever, body aches, headache, nausea, lethargy, and sometimes a rash. Salmonella typhi is a Gram-negative, rod-shaped bacterium that can lead to severe symptoms such as high fever, delirium, and dehydration. Additionally, carriers of the disease may not show symptoms, posing a risk of spreading to others as seen in historical cases like that of "Typhoid Mary." Other symptoms of typhoid fever might include abdominal pain and skin rashes.
The presence of Salmonella pathogenicity islands (SPIs) in S. typhi contains genes for its virulence factors, including the Vi antigen responsible for capsule production and the A2B5 toxin, which contribute to the signs and symptoms during the acute phase of typhoid fever. Overall, typhoid fever is a serious illness with a significant untreated mortality rate and requires prompt medical attention.