Human herpesvirus-8 (HHV-8) causes Kaposi's sarcoma (KS) and lymphoproliferative disorders in both HIV-infected and uninfected patients. HHV-8 has a worldwide occurrence but infection rates vary according to a combination of geographic and behavioral risks. The main transmission route seems to be sexual, nevertheless, nasal secretions, saliva, blood, and organ graft have been proposed. HHV-8 was postulated as a new infectious agent for screening in blood donors. The aim of this study was to evaluate the prevalence of antibodies against HHV-8 antigens in blood donors of South America. Serum samples from 2,470 blood donors from Argentina, Brazil, and Chile corresponding to five geographic regions were studied by indirect immunofluorescence assay (IFA). Seroprevalence rate was 3.7% (92/2,470; 95% CI 2.9-4.5) in the entire blood donor population distributed as follows: Argentina, 4.0% (Buenos Aires city, 4.3%; Bahia Blanca, 2.4%; and Córdoba, 4.0%), Campinas (Brazil), 2.8%; and Santiago de Chile, 3.0%. There was no difference (P>0.05) between men and women or age related, except in Brazil where positive cases were 30-49-year-old males. The present study, which includes different geographical areas of multiple countries from South America, has not been done before. The results show similar prevalence rates among the studied zones corresponding to low-prevalence regions. South America is a large sub-continent with a wide spectrum of population and geographical characteristics, thus, more HHV-8 prevalence studies should be necessary to establish possible regional differences.

Influenza virus (InfV) infection during pregnancy is a known risk factor for neurodevelopment abnormalities in the offspring, including the risk of schizophrenia, and has been shown to result in an abnormal behavioral phenotype in mice. However, previous reports have concentrated on neuroadapted influenza strains, whereas increased schizophrenia risk is associated with common respiratory InfV. In addition, no specific mechanism has been proposed for the actions of maternal infection on the developing brain that could account for schizophrenia risk. We identified two common isolates from the community with antigenic configurations H3N2 and H1N1 and compared their effects on developing brain with a mouse modified-strain A/WSN/33 specifically on the developing of dopaminergic neurons. We found that H1N1 InfV have high affinity for dopaminergic neurons in vitro, leading to nuclear factor kappa B activation and apoptosis. Furthermore, prenatal infection of mothers with the same strains results in loss of dopaminergic neurons in the offspring, and in an abnormal behavioral phenotype. We propose that the well-known contribution of InfV to risk of schizophrenia during development may involve a similar specific mechanism and discuss evidence from the literature in relation to this hypothesis.

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