Table 2. Case definitions for infections sought in systematic review of severe febrile illness in low- and middle-income countries.
| Group | Disease | Confirmed case definition |
|---|---|---|
| Blood and tissue parasites | Babesiosis | Blood film and identification; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens; NAAT |
| Malaria | Blood film and identification; rapid diagnostic test; NAAT | |
| Trypanosomiasis | Blood film and identification | |
| Visceral leishmaniasis | Tissue biopsy or aspirate and identification | |
| Invasive bacterial infections | Bloodstream infection | Blood culture and isolation; urine antigen testing for Streptococcus pneumoniae (adolescents and adults only) or Legionella pneumophila serogroup 1 |
| Invasive fungal infections | Fungemia | Blood culture and isolation |
| Blastomycosis | Fungal culture and isolation; antigen testing | |
| Candidosis | Fungal culture and isolation | |
| Coccidioidomycosis | Fungal culture and isolation; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens; NAAT | |
| Cryptococcosis | Fungal culture and isolation; antigen testing | |
| Histoplasmosis | Fungal culture and isolation; antigen testing of urine or serum; ELISA; NAAT | |
| Bacterial zoonoses | Anaplasmosis | Culture and isolation; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens; NAAT |
| Brucellosis | Culture and isolation; serology with ≥4-fold rise in MAT titer between acute- and convalescent-phase serum specimens | |
| Borreliosis | Culture and isolation; blood film; NAAT | |
| Cat scratch disease | Culture and isolation; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens | |
| Carrión's disease | Culture and isolation; serology with ≥4-fold in reciprocal titer between acute- and convalescent-phase serum specimens | |
| Ehrlichiosis | Culture and isolation; serology with ≥4-fold in reciprocal titer between acute- and convalescent-phase serum specimens; NAAT | |
| Leptospirosis | Culture and isolation; serology with ≥4-fold in MAT titer between acute- and convalescent-phase serum specimens; NAAT | |
| Q fever | Culture and isolation; serology with ≥4-fold rise in IFA titer between acute- and convalescent-phase serum specimens; NAAT | |
| Scrub typhus | Culture and isolation; serology with ≥4-fold rise in IFA titer between acute- and convalescent-phase serum specimens, NAAT | |
| Spotted fever group rickettsiosis | Culture and isolation; serology with ≥4-fold rise in IFA titer between acute- and convalescent-phase serum specimens; NAAT | |
| Typhus group rickettsiosis | Culture and isolation; serology with four-fold or greater rise in IFA titer between acute- and convalescent-phase serum specimens; NAAT | |
| Trench fever | Culture and isolation; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens | |
| Viral infections | Dengue fever | Viral culture and isolation; NAAT; NS1; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens; |
| Chikungunya | Viral culture and isolation; NAAT; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens | |
| Influenza | Viral culture and isolation; NAAT on nasopharyngeal and blood specimens; serology with ≥4-fold rise in HAI titer between acute- and convalescent-phase serum specimens | |
| Japanese B encephalitis | Viral culture and isolation; NAAT; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens | |
| Measles | Viral culture and isolation; NAAT; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens | |
| West Nile virus disease | Viral culture and isolation; NAAT; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens | |
| Yellow fever | Viral culture and isolation; NAAT; serology with ≥4-fold rise in reciprocal titer between acute- and convalescent-phase serum specimens |
NAAT = Nucleic acid amplification test; MAT = microagglutination test; IFA = immunofluorescence assay; HAI = haemagglutination inhibition assay.