Table 2.

Diagnostic Tests for Flea-Borne Typhus.

Test	Year Devised	Advantages	Disadvantages
Weil-Felix Test (WFt)	1915 [119]	requires minimal equipment; generally positive in the first week of infection [120]	two or more sequential sera were needed for better accuracy [122,123]; cross-reaction between rickettsial infections [120]; poor sensitivity and specificity [124]
Complement Fixation (CF)	1936 [126]; not practical until 1941 [129]	able to differentiate species of rickettsiae; CF antibodies may be present up to ≥5 years after the illness [141].	delayed positivity (second week) [120]; technically difficult [131]; lower sensitivity than IFA [133]
Indirect Immuno-fluorescence Assay (IFA)	1976 [134]	considered current gold standard; IgG sensitivity ≥83%; specificity ≥ 93% [142]; median half-life of R. typhi IgG was 177 days [143]	paired sera for confirmation; negative results during the first 7–14 days of infection; cross-reaction with other rickettsiae [138]; requires fluorescence microscope and reference laboratory
Latex Agglutination	1995 [137]	rapid; requires minimal equipment	less sensitive than IFA [144]
Enzyme-linked Immunosorbent Assay (ELISA)	1977 [144]	rapid; requires minimal equipment	comparable sensitive to IFA in some studies [144], but inadequate validation [138]
Polymerase Chain Reaction (PCR)	2007 [139]	potential for early diagnosis	low sensitivity when using blood samples [140,143]
Loop-Mediated Isothermal Amplification	2014 [140]	potential for rapid, point-of-care assay; does not require thermocycler	low sensitivity when using blood samples (48%) [140]