What type of bacteria is most commonly associated with diseases such as typhoid fever?

Bacilli are rod-shaped bacteria that are known for their association with various diseases, including typhoid fever. Typhoid fever is specifically caused by the bacterium Salmonella typhi, which falls under the category of bacilli. The rod shape of bacilli allows them to survive and thrive in different environments, contributing to their pathogenic capabilities.

Cocci, which are spherical bacteria, and diplococci, a subtype of cocci that occur in pairs, are associated with other infections such as pneumonia and strep throat rather than typhoid fever. Spirilla, with their spiral shape, are typically associated with conditions like syphilis or other diseases but are not linked to typhoid fever. This distinction highlights the importance of identifying the shape and classification of bacteria when studying their associated diseases.