BACKGROUND Dengue virus type 4 (DENV-4) was first reported in Brazil in 1982 and since then no more cases were detected again in Brazil until 2010, when the virus was reintroduced. Over the following years, the virus spread to several Brazilian states and resulted in about 1,400,000 dengue cases, in 2013. The largest number of cases were documented in the Southeast macro-region. OBJECTIVES To determine the phylogeography of DENV-4 Genotype IIB strains isolated during the epidemics in 2012-2013 in São Paulo, Brazil, we aimed to contextualise the contribution of viruses sampled in different localities across the overall movement of DENV-4 in Brazil. METHODS Based on the envelope gene sequences retrieved from GenBank, we employed a Bayesian phylogeographic approach to assess the spatiotemporal dynamics of DENV-4 Genotype IIB in São Paulo, Brazil. FINDINGS The dispersal dynamics of DENV-4 Genotype IIB in Brazil indicated Rio de Janeiro and Mato Grosso states as the most likely routes toward São Paulo before the 2012-2013 outbreak. Likewise, Guarujá and São José do Rio Preto facilitated viral spread and transmission to other localities in the South and Southeast macro-regions in Brazil. CONCLUSIONS The spread pattern of DENV-4 Genotype IIB strains across the country supports two independent introductions of the virus in São Paulo in a short period of time. Furthermore, São Paulo appears to have played a pivotal role in the dissemination of DENV-4 to other locations in Brazil.

ABSTRACT OBJECTIVES: The main objective was to evaluate HBV infection and occult HBV infection (OBI) cases in mentally ill patients based on serological and molecular profiles. MATERIAL AND METHODS: Serum samples of 333 long-stay mentally ill patients were tested for the prevalence of HBV markers by serological (ELISA) and molecular (PCR) assays. The PCR products were sequenced to determine viral genotypes. RESULTS: It was observed a global prevalence of 12.9% (43/333) for HBV infection markers, considering HBsAg and/or anti-HBc positivity. Fourteen samples tested positive for anti-HBs alone. All samples positive (n= 57) for any HBV serological markers were tested for HBV-DNA and six were positive: HBsAg/anti-HBc (n = 1), anti-HBc/anti-HBs (n = 1), anti-HBs alone (n = 1), and anti-HBc alone (n = 3). The rate of OBI was 9.2% (5/54) from samples that were anti-HBc and/or anti-HBs positive. All sequenced samples were characterized as genotype A. CONCLUSION: The high rate of HBV infections found in this study suggests the possibility of HBV transmission due to risk factors displayed by some patients, and highlights the importance of vaccination of susceptible patients and the staff of that institution.