Fever after exposure to fresh water or animals (leptospirosis, Q fever, brucellosis, tularaemia)

• State on the prescription the date of onset of signs and the exposure (freshwater, rodents, occupation). Sample before any antibiotic.

Laboratory tests

• FBC with platelets
• Serum creatinine with eGFR
• AST
• ALT
• Bilirubin
• Leptospira PCR on blood (up to day 10 of signs, before antibiotic)if neededBacteraemic phase: blood PCR preferred in the first 10 days, before any antibiotic therapy ^[2,3].
• Anti-Leptospira IgM (EIA) (from day 7-8)if neededFrom about day 7 (IgM detectable for 2 to 3 months), or if PCR is unavailable, negative or too late ^[3]; serology is mainly informative from day 8-10 ^[2].

Targeted laboratory tests

• Q fever serology (screening, phase II antigen)if neededExposure to farm animals or animal contact (Q fever) ^[9]; titration done by the laboratory if the screening test is positive ^[3].
• Serodiagnosis of brucellosis (Wright, Rose Bengal)if needednon-French guidelineExposure in livestock farming (brucellosis) or unpasteurised milk ^[9].
• Tularaemia serology (to be repeated: seroconversion or 4-fold rise in titres)if neededContact with game, hares or small rodents, or tick bite, with eschar or lymphadenopathy: direct diagnosis is by PCR on an eschar swab; serology is delayed ^[9,10].