Mayaro Alphavirus is an arbovirus that causes outbreaks of acute febrile illness in the Amazon region of South America. We show here the cases of Mayaro fever that occurred in 2007-2008, in Manaus, a large city and capital of the Amazonas State, in Western Brazilian Amazon. IgM antibodies to Mayaro virus (MAYV) were detected by an enzyme immunoassay using infected cell cultures as antigen in the sera of 33 patients from both genera and 6-65 years old. MAYV genome was also detected by RT-PCR in the blood of 1/33 of these patients. The patients presented mainly with headache, arthralgia, myalgia, ocular pain, and rash. These cases of Mayaro fever are likely to represent the tip of an iceberg, and probably a much greater number of cases occurred in Manaus in the study period.

The influence of hepatitis B virus (HBV) genotypes in the natural history of the disease and its response to antiviral treatment have been addressed in many studies. In Brazil, studies on HBV genotype circulation have been restricted to specific population groups and states. Here, we have conducted a nationwide multicentre study with an unprecedented sample size representing all Brazilian regions in an effort to better understand the viral variants of HBV circulating among chronic carriers. Seven HBV genotypes were found circulating in Brazil. Overall, HBV/A was the most prevalent, identified in 589 (58.7 %) samples, followed by HBV/D (23.4 %) and HBV/F (11.3 %). Genotypes E, G, C and B were found in a minor proportion. The distribution of the genotypes differed markedly from the north to the south of the country. While HBV/A was the most prevalent in the North (71.6 %) and Northeast (65.0 %) regions, HBV/D was found in 78.9 % of the specimens analysed in the South region. HBV/F was the second most prevalent genotype in the Northeast region (23.5 %). It was detected in low proportions (7 to 10 %) in the North, Central-West and Southeast regions, and in only one sample in the South region. HBV/E was detected in all regions except in the South, while monoinfection with HBV/G was found countrywide, with the exception of Central-West states. Our sampling covered 24 of the 26 Brazilian states and the Federal District and is the first report of genotype distribution in seven states. This nationwide study provides the most complete overview of HBV genotype distribution in Brazil to date and reflects the origin and plurality of the Brazilian population.

The HIV-1 epidemic in Brazil is driven by subtypes B, F1, and C and recombinants forms among those subtypes. The distribution of HIV-1 subtypes, however, may vary across different Brazilian regions and the molecular epidemiologic profile in Northern Brazil remains poorly explored. HIV-1 pol sequences were obtained from 305 patients failing antiretroviral therapy followed at outpatient clinics from five Northern Brazilian states. The most prevalent HIV-1 clade observed in the Northern Brazilian region was subtype B (81%), followed by BF1 recombinants (10%), subtype F1 (4%), subtype C (3%), BC recombinants (2%), and BU recombinants (1%). Although HIV-1 subtype B was the predominant HIV-1 clade in Northern Brazil, its prevalence greatly varies among different states, ranging from 63% in Rondônia to 92% in Acre. Among the 37 HIV-1 recombinant sequences detected in the Northern Brazilian region, nine (24%) displayed a unique recombinant form structure, five (14%) a CRF28/29_BF-like structure, and four (11%) a CRF31_BC-like structure. Two other BF1 recombinant patterns were identified in 16 (43%) and three (8%) samples that may correspond to two potentially new CRFs_BF characteristic of the Northern region. This study reveals that despite the low spatial connectivity with other Brazilian regions, the genetic complexity of the HIV-1 epidemic in Northern Brazil is very high and that the molecular epidemiologic pattern may vary across different northern states, reflecting a complex epidemic with multiple independent viral introductions into this Brazilian region.

No abstract

SUMMARYThe natural co-infection with dengue virus can occur in highly endemic areas where different serotypes have been observed for many years. We report here four cases of DENV-3/DENV-4 co-infection detected by serological and molecular tests among 674 patients with acute undifferentiated fever from the tropical medicine reference center of Manaus City, Brazil, between 2005 and 2010. Analysis of the sequences obtained indicated the presence of genotype 3 and 1 for DENV-3 and DENV-4 respectively. KEYWORDS:Brazil; Dengue; Co-infection; Flavivirus.Dengue Fever is the most important arboviral disease worldwide. Dengue viruses (DENVs) belong to the genus Flavivirus, family Flaviviridae. These are single-stranded positive-sense RNA viruses grouped into four antigenically related, but distinct, serotypes named DENV-1, 2, 3 and 4 5 . Since the first laboratory-confirmed DENV cases at Roraima 1981-1982, more than four million cases of dengue have been reported in Brazil 11 . In Manaus, the capital of the Amazonas State in Brazil, all four dengue serotypes have already been reported 3,4 . Dengue virus co-infection cases are poorly documented in literature, although our results demonstrate that such cases might be more common than expected, mostly in hyperendemic areas.From January 2005 to December 2010, 674 patients with acute undifferentiated fever were treated at a reference center of Tropical Medicine (Fundação de Medicina Tropical Doutor Heitor Vieira Dourado -FMT-HVD, Manaus, Brazil). These patients were tested for malaria by thick blood analyses, and all patients with negative results were asked to participate in this study. The participants signed an informed consent form that was approved by the FMTAM Ethical Committee Board (272/2005). Two blood samples were collected from each patient, one in the acute phase of the disease and the other in the convalescent form. Sera from the convalescent phase were used for detection of antidengue immunoglobulin M (IgM) specific antibodies by MAC-ELISA, as previously described 9 .Acute-phase samples were used in two tests: one for viral isolation in C6/36 Aedes albopictus cell line, followed by viral identification using an indirect immunofluorescent test with dengue type-specific monoclonal antibodies 7 , kindly provided by Centers for Disease Control and Prevention (CDC), Atlanta, Georgia USA; and the other for specific DENV nucleic acid amplification. RNA was extracted directly from serum samples with the QIAamp Viral RNA Mini-Kit (Qiagen, USA), following manufacturer´s instructions and submitted to RT-PCR to be followed by semi-nested multiplex PCR as previously described for DENV detection and typing 10 . When samples were positive for any serotype of DENV, a second semi-nested PCR, this time in a singleplex format, with a type-specific primer (DENV-1 to DENV-4) was performed for confirmation. Amplicons from the C/PrM region were purified and sequenced in both directions by using the BigDye Terminator Cycle Sequence Kit (Applied Biosystems, USA). The genotypes were detec...