Parvovirus B19 (B19), also known as "erythema infectiosum", is a disease that occurs in smaller outbreaks during late winter and early summer; and in Denmark an epidemic occurs every three years. The symptoms vary from fever, fatigue and the characteristic maculopapoulous erythema to asymptomatic cases in 50% of the infected patients. Two-thirds of the Danish population have been infected. The virus has a broad spectrum of clinical manifestations ranging from erythema nodosum in children, arthralgia/arthritis (especially in adults), aplastic crisis in patients with haemolytic anaemia, chronic anaemia in immunocompromised patients, to hydrops foetalis following acute infection during pregnancy. In two adult females aged 41 and 35 years with persisting fatigue, malaise, transitory swelling and arthralgia we found elevated ALT and alkaline phosphatase (pt. 1), despite no serological evidence of hepatitis, cytomegalovirus (CMV), or Epstein-Barrvirus and no story of alcohol consumption or recent travelling outside Denmark. Ongoing B19 infection was diagnosed by ELISA and confirmed by B19 DNA PCR in case 2 and IgG avidity and epitope-type specificity in case 1, who was B19 DNA negative in three different samples. The concentrations of alkaline phosphatase and ALT returned to normal as the antibody response shifted from acute B19 infection to IgG positivity. In conclusion we suggest that a serological test and/or B19 DNA for B19 infection is a relevant test to undertake when screening patients for viral hepatitis especially during B19 epidemics and in exposed individuals.