Serology

Serologic Diagnosis of typhoid fever
Typhoid fever "Enteric fever"
Typhoid fever is a syndrome caused by Salmonellae Spp. This bacteria are often pathogenic for humans or animals when acquired by the oral route. They are transmitted from animals and animal products to humans where they cause enteritis, systemic infection and enteric fever.
Serologic methods:
Serologic techniques are used to identify unknown cultures with known sera and also be used to determine antibody titers in patients with unknown disease.
The titer: It is the highest dilution that gives a positive (antigen-antibody reaction), for example: the highest dilution at which agglutination occurs is 1:320, the titer is 320 antibody units per milliliter of serum. A higher titer mean there is a greater antibody response of the individual to the disease.
Agglutination test
This test is depend on the agglutination between a suspensions of Salmonellae different antigens and anti- Salmonellae antibodies in patients sera. The presence or absence of visible agglutination is usually related with presence or absence of anti- Salmonellae antibodies in the tested samples.
Samples: fresh, clear serum. After the serum has been separated it must be stored at 2-8°C up to one week, or at -20°C for longer periods.