Salmonella typhi

Introduction

Salmonella typhi causes typhoid fever. It causes symptoms of fever, severe headaches, nausea, and loss of appetite. Other characteristics that can arise are: diarrhea, enlargement of the spleen, and the possible enlargement of the spleen.

Hosts

Humans.

Transmission / Exposure Route

Transmission occurs via the fecal-oral route from infected individuals to healthy ones. Poor hygiene and eating/drinking contaminated food/water can also infect others. Drinking contaminated water is the most common way of infection occurring.

Case Fatality Ratio

Typhoid fever affects roughly 17 million people annually, causing nearly 600,000 deaths. Untreated typhoid fever cases result in mortality rates ranging from 12-30% while treated cases allow for 99% survival. 

Incubation Period

Most Salmonella bacteria have an incubation period of 4 to 7 days.

Microbiology

A Gram negative, nonmotile, rod shaped bacteria. It is approximately 2-5 microns long. 

Enviromental Survival

It grows in a facultative anaerobic environment, so it can survive in a dry environment for weeks and many months in water. It is susceptible to various antibiotics.