What causes typhoid fever?
Typhoid fever is caused by an infection with a gram-negative bacterium called Salmonella typhi or a related bacteria; Salmonella paratyphi which has different subtypes (A, B or C). Both of these bacteria cause slightly different, but we generally call infection by both of these typhoid fever.
These bacteria are ingested orally, survive in the stomach, and then enter into the duodenum; which is the first part of the small intestine. When they enter the duodenum, they can penetrate through the intestinal epithelium and invade the lymphoid tissue.

How is Typhoid fever transmitted?
Humans are actually the only reservoir for this type of bacteria, so it has to come from a human to another human. This can be through direct contact or indirect via contaminated food or water.

The risk factors for contracting typhoid fever include;
Being a child or young adult: Children and young adults are more susceptible to typhoid fever.
Overcrowding: Lots of people gathered in a place. It can be easily transmitted through direct or indirect.
Poor sanitation: If there is poor sanitation with regards to food or water, it is easier to transmit typhoid fever.

Developmental stages & symptoms of typhoid fever
Typhoid can be summed up into a fever & abdominal pain.
But more specifically, with this infection, there is a symptom onset that occurs roughly 5 to 21 days after ingestion of the bacteria (depends on age, health, gastric acidity of your stomach, and number of organisms that were ingested)
In the 1st week of infection, we have what we call a Stepwise fever. This is the first symptom you are going to see. It is called a stepwise fever because you will gradually see a step-like increase in fever. Meaning, you will see a temperature, it will bump up to a higher level, and this will plateau, and it will bump up to another higher level, and plateau, and on.
In the 2nd week of infection, the affected individual may start experiencing abdominal pain, and some spots on the skin commonly referred to as Rose Spots. If pushed, these spots tend to disappear, and then reappear.

In the 3rd week, some of the worsening symptoms start coming up. This includes intestinal bleeding, intestinal perforation, and more.
Some other symptoms of typhoid fever include;
Headaches
Disordered sleep patterns
Diarrhea or constipation

Diagnosis
The confirmatory diagnosis of typhoid test is blood culture. Stool and urine culture may be diagnostic too depending on the stage of the disease.

Common test like widal and typhidot are only suggestive not diagnostic and should never be used as the only investigative measures. It must be combined with other test like full blood COUNT (FBC), erythrocyte sedimentation rate(ESR) or stool culture.

Treatment
The treatment of typhoid fever depends on local resistance patterns. It is best to see the doctor immediately if you suspect that you have typhoid fever.