Hantavirus infections in Spain: analysis of sera from the general population and from patients with pneumonia, renal disease and hepatitis.

BACKGROUND: Hantaviruses are rodent borne viruses in the family Bunyaviridae that cause significant morbidity in large areas of Europe. There are only a few reports available on hantavirus infections from Spain. Although the results of these earlier studies indicated the presence of hantavirus infections, no confirmative or serotype-specific analyses have been performed.

OBJECTIVES: To investigate whether hantaviruses cause human infection/disease in Spain.

STUDY DESIGN: Ten thousand, four hundred and eighteen serum samples from the general population and 599 sera from 492 patients with potential hantavirus infections (renal disease, pneumonia or hepatitis) were initially screened by immunofluorescence assay (IFA) using Hantaan, Seoul and Puumala hantavirus antigens. Altogether 193 suspicious samples (165 from healthy people and 28 from patients) were selected for confirmation by quality-assured assays.

RESULTS AND CONCLUSIONS: Of the 165 pre-screened serum samples from healthy individuals, only five could be confirmed by IFA for hantavirus-reactive antibodies (using Dobrava, Saaremaa, Hantaan or Puumala virus antigens). In addition, one serum was found weakly positive for hantavirus-reactive IgG by ELISA using recombinant Saaremaa virus (SAAV) nucleocapsid (N) antigen, and subsequently confirmed by immunoblotting. Thus, the results indicated a low (0.06%) total antibody prevalence to hantaviruses in Spain. Of 28 pre-screened serum samples from hospitalized patients, eight reacted as positive or showed border-line reactivities for hantavirus-specific IgM by ELISA using recombinant Saaremaa and Puumala virus N antigens. The IFA/ELISA reactive/border-line samples were subsequently analyzed by a focus reduction neutralization test, which revealed low titers (1:80) against SAAV in two samples from a patient with hepatic disease. The nature of the hantavirus(es) potentially involved remain, however, unknown, since none of the positive samples showed neutralizing titers of the expected range to any of the known European hantaviruses.