Diagnosis is made by any blood, bone marrow, or stool cultures and with the Widal test (demonstration of antibodies against Salmonella antigens O-somatic and H-flagellar). In epidemics and less wealthy countries, after excluding malaria, dysentery, or pneumonia, a therapeutic trial time with chloramphenicol is generally undertaken while awaiting the results of the Widal test and blood and stool cultures. Widal test Widal test card The Widal test is used to identify specific antibodies in the serum of people with<unk>  by using antigen-antibody interactions. In this test, the serum is mixed with a dead bacterial suspension of salmonella with specific antigens. If the patient's serum contains antibodies against those antigens, they get attached to them, forming clumps. If clumping does not occur, the test is negative. The Widal test is time-consuming and prone to significant false positives. It may also be falsely negative in recently infected people. But unlike the<unk> ot test, the Widal test quantifies the specimen with titres. Rapid diagnostic tests Rapid diagnostic tests such as Tubex,<unk> ot, and Test-It have shown moderate diagnostic accuracy.<unk> ot<unk> ot is based on the presence of specific IgM and IgG antibodies to a specific 50Kd OMP antigen. This test is carried out on a cellulose nitrate membrane where a specific S. typhi outer membrane protein is attached as fixed test lines. It separately identifies IgM and IgG antibodies. IgM shows recent infection; IgG signifies remote infection. The sample pad of this kit contains colloidal gold-anti-human IgG or gold-anti-human IgM. If the sample contains IgG and IgM antibodies against those antigens, they will react and turn red. The<unk> ot test becomes positive within 2–3 days of infection. Two colored bands indicate a positive test. A single control band indicates a negative test. A single first fixed line or no band at all indicates an invalid test.<unk> ot's biggest limitation is that it is not quantitative, just positive or negative. Tubex test The Tubex test contains two types of particles: brown magnetic particles coated with antigen and blue indicator particles coated with O9 antibody. During the test, if antibodies are present in the serum, they will attach to the brown magnetic particles and settle at the base, while the blue indicator particles remain in the solution, producing a blue color, which means the test is positive. If the serum does not have an antibody in it, the blue particles attach to the brown particles and settle at the bottom, producing a colorless solution, which means the test is negative.
Typhoid fever
Leptospirosis
Trench fever
Lassa fever
Cotton fever
Boutonneuse fever
Yellow fever
Paratyphoid fever