- Incubation period of 2 to 26 days (average 10 days)
- Abrupt onset of fever, rigors, myalgias, and headache in 75 to 100% of patients
- Dry cough (25-35% of cases)
- Nausea, vomiting, and diarrhea (50% of cases)
- Less common symptoms include joint aches, bone pain, sore throat, and abdominal pain
- Approximately 7 to 40% of patients may have muscle tenderness, an enlarged spleen or liver, enlarged lymph glands, sore throat, muscle rigidity, abnormal lung sounds, or skin rash
- White blood cell (WBC) counts are generally less than 10,000.
- Urinalysis frequently is abnormal.
- Elevated creatine kinase is found in approximately 50% of patients.
- About 40% of patients have minimal to moderate elevations of liver enzymes.
- Diagnosis is most frequently made by serologic (antibody) testing.
- Bacteria is best visualized by dark field microscopy, silver stain, or fluorescent microscopy.
- Unlike Treponema pallidum, Leptospira can be grown from blood, urine, and CSF. It is slow growing and the laboratory needs to be notified.
- Isolation of the organism from the blood is successful in 50% of cases.
- Urine cultures become positive during the second week of the illness and remain so for up to 30 days.