Typhoid fever

Typhoid fever, also known simply as typhoid, is a bacterial infection due to Salmonella typhi that causes symptoms.^[3] Symptoms may vary from mild to severe and usually begin six to thirty days after exposure.^[1][2]Often there is a gradual onset of a high fever over several days.^[1]Weakness, abdominal pain, constipation, and headaches also commonly occur.^[2][6] Diarrhea is uncommon and vomiting is not usually severe.^[6]Some people develop a skin rash with rose colored spots.^[2] In severe cases there may be confusion.^[6] Without treatment, symptoms may last weeks or months.^[2] Other people may carry the bacterium without being affected; however, they are still able to spread the disease to others.^[4]Typhoid fever is a type of enteric fever along with paratyphoid fever.^[3]

The cause is the bacterium Salmonella Typhi, also known as Salmonella enterica serotype Typhi, growing in the intestines and blood.^[2][6] Typhoid is spread by eating or drinking food or water contaminated with the fecesof an infected person.^[4] Risk factors include poor sanitation and poor hygiene.^[3] Those who travel to the developing world are also at risk^[6]and only humans can be infected.^[4] Diagnosis is by either culturing the bacteria or detecting the bacterium's DNA in the blood, stool, or bone marrow.^[2][3][5] Culturing the bacterium can be difficult.^[10] Bone marrow testing is the most accurate.^[5] Symptoms are similar to that of many other infectious diseases.^[6] Typhus is a different disease.^[11]

A typhoid vaccine can prevent about 30% to 70% of cases during the first two years.^[7] The vaccine may have some effect for up to seven years.^[3]It is recommended for those at high risk or people traveling to areas where the disease is common.^[4] Other efforts to prevent the disease include providing clean drinking water, better sanitation, and better handwashing.^[2][4] Until it has been confirmed that an individual's infection is cleared, the individual should not prepare food for others.^[2] Treatment of disease is with antibiotics such as azithromycin, fluoroquinolones or third generation cephalosporins.^[3] Resistance to these antibiotics has been developing, which has made treatment of the disease more difficult.^[3]

In 2015, there were 12.5 million new cases worldwide.^[8] The disease is most common in India.^[3] Children are most commonly affected.^[3][4] Rates of disease decreased in the developed world in the 1940s as a result of improved sanitation and use of antibiotics to treat the disease.^[4] Each year in the United States, about 400 cases are reported and it is estimated that the disease occurs in about 6,000 people.^[6][12] In 2015, it resulted in about 149,000 deaths worldwide – down from 181,000 in 1990 (about 0.3% of the global total).^[9][13] The risk of death may be as high as 20% without treatment.^[4] With treatment, it is between 1 and 4%.^[3][4] The name typhoid means "resembling typhus" due to the similarity in symptoms.^[14]