Optimizing typhoid fever case definitions by combining serological tests in a large population study in Hechi City, China.
Blood culture-based diagnosis can only detect a fraction of the total burden of Salmonella enterica subsp. enterica serovar Typhi. The objective of the study was to detect additional typhoid fever cases through serological tests. A total of 1732 prolonged fever episodes were evaluated using three serological tests, Widal, Tubex and Typhidot-M in a typhoid fever endemic area of southern China. A case definition which included a positive Widal test (TO>or=80 & TH>A), a positive Tubex test (>or=4) and a positive Typhidot-M test, increased the detection of cases by more than twofold from 13 to 28 cases. The case definition has a specificity of 100% and a sensitivity of 39%. Case definitions based on combinations of serological tests can detect additional typhoid fever cases with higher specificity than a single serological test. Improved case detection is essential to understand the true disease burden and can help to boost the power of intervention trials.
Dong
B
B
Guangxi Center for Disease Prevention and Control, Nanning, Guangxi, China.
Galindo
C M
CM
Shin
E
E
Acosta
C J
CJ
Page
A L
AL
Wang
M
M
Kim
D
D
Ochiai
R L
RL
Park
J
J
Ali
M
M
Seidlein
L V
LV
Xu
Z
Z
Yang
J
J
Clemens
J D
JD
D000293:Adolescent; D000328:Adult; D000372:Agglutination Tests / Q000379:methods; D002648:Child; D002675:Child, Preschool; D002681:China; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014435:Typhoid Fever / Q000175:diagnosis*