Human Parvovirus B19 Infection in 15 Adults ―Two-year Toho University Hospital Study

Human parvovirus B19 infection in adults features clinical symptoms and laboratory abnormal findings unlike those in children commonly associated with cheek rash. We diagnosed 15 adult cases based on the positive increase in anti-parvovirus B19 IgM antibody (8.89±7.86 mean±SD, enzyme immunoassay (EIA)). Antibody titer was measured in 78 patients clinically showing fever, edema, exanthema, arthralgia, and myalgia among 11,040 outpatients first visiting the hospital from January 2005 to December 2007. Based on clinical and laboratory findings for these 15 cases, we recommended that physicians taking anti-parvovirus B19 antibody blood samples note whether (1) the level of C reactive protein is negative or low and without leucocytosis ; (2) a miliary rash is observed in short duration (rarely facial) ; (3) arthralgia and/or myalgia is present in the extremities (sometimes asymmetrical) ; (4) edema is present in the extremities, especially finger, ankle, or sole of the foot ; (5) contact has been made with ill children ; (6) flu-like symptoms occur such as fatigue, headache, or fever ; and (7) normo- or hypocomplementemia and/or antinuclear antibody is positive. Patients who fullfill requirement (1) plus at least three of requirements (2) through (7) should have a blood sample taken. We retrospectively studied 78 cases using these requirements, finding their sensitivity to be 100％(15/15), specificity to be 88.9％(56/63), positive predictive value to be 68.1％(15/22) and negative predictive value to be 100％(56/56). These requirements are thus useful in selecting patients for measuring antibody titer and definitively diagnosing severe or persistent parvovirus B19 infection occationally observed in adults.