Zika virus (ZIKV), a mosquito-borne flavivirus, belongs to the Flaviviridae family, genus Flavivirus. ZIKV was initially isolated in 1947 from a sentinel monkey in the Zika forest, Uganda. Little clinical importance was attributed to ZIKV, once only few symptomatic cases were reported in some African and Southeast Asiatic countries. This situation changed in 2007, when a large outbreak was registered on the Yap Island, Micronesia, caused by the Asian ZIKV lineage. Between 2013 and 2014, ZIKV spread explosively and caused many outbreaks in different islands of the Southern Pacific Ocean and in 2015 autochthonous transmission was reported in Brazil. Currently, Brazil is the country with the highest number of ZIKV-positive cases in Latin America. Moreover, for the first time after the discovery of ZIKV, the Brazilian scientists are studying the possibility for the virus to cause severe congenital infection related to microcephaly and serious birth defects due to the time-spatial coincidence of the alarming increase of newborns with microcephaly and the Brazilian ZIKV epidemic. The present review summarizes recent information for ZIKV epidemiology, clinical picture, transmission, diagnosis and the consequences of this emerging virus in Brazil.

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Human T cell lymphotropic virus type 1 (HTLV-1) is the etiological agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T cell leukemia/lymphoma. The development of HAM/TSP, a chronic neuroinflammatory disease, is correlated to complex interaction between the host immune response and the infecting virus. Tax expression plays an important role in HAM/TSP pathogenesis by activating various cellular genes, including the cytokines interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). Exosomes have emerged as an important factor of cell-to-cell communication contributing to diverse cellular processes, including immune modulation. Considering the potential role of exosomes in modulating the immune response and inflammation, the main objective of this study was to examine if HTLV-1-infected cells produce exosomes carrying viral proteins or inflammatory molecules, which can participate in the chronic inflammation that is observed in patients with HAM/TSP. Exosomes were isolated from HTLV-1-infected cell line, evaluated for the tax mRNA presence, and tested for the ability to activate peripheral mononuclear cells (PBMC) in inducing an inflammatory immune response. We observed that the proinflammatory cytokines, IFN-γ and TNF-α, were upregulated in T cells after treatment of the PBMC with Tax-carrying exosomes compared to the negative control. Interleukin-4, Granzyme B, and Perforin did not show alterations. Taken together, these results suggest that exosomes carrying tax-mRNA isolated from HTLV-1-infected cells might induce the production of proinflammatory cytokines and activate T helper (Th), and not Th-immune response. If this finding is further confirmed, this study may have impact on investigations on the pathogenesis of HAM-TSP and the inflammatory response involved in this disease.

The infection of human parvovirus B19 (B19V) is a common event in the general population, including volunteer blood donors. In some cases it can be asymptomatic and can remain persistent for a long period of time. The objective of this study was to examine the B19V DNA prevalence and viral load in first-time volunteer blood donors. Blood samples were collected from 91 primary blood donors at the Regional Blood Center of Ribeirão Preto, Southeast Brazil. Viral detection and quantitation was performed by an in-house TaqMan Ò real-time PCR with high sensitivity. B19V DNA was detected in one male blood donor (1.0 %) and was characterized by a very low viral load (537.36 copies/mL). Our studies demonstrate that B19V DNA at low titer may be present in apparently healthy individuals. Sensitive molecular diagnostic tools can be applied for the screening of fresh blood derived products in order to prevent transfusion-transmitted B19V infection. Keywords Human parvovirus B19 Á B19V Á Viral quantitation Á Blood donorsHuman parvovirus B19 (B19V), a small icosahedral virus (19-22 nm), is the prototype member of the Erythrovirus genus (Parvoviridae family). B19V infection is a common finding in the general population and demonstrates marked seasonality. Clinical manifestations of B19V infection in children and adults may include erythema infectiosum (fifth disease) or arthropathy, nevertheless, great proportion of the infected individuals remain asymptomatic [1]. Therefore, in the general population B19V infections among blood donors can be considered a normal event and many of them have asymptomatic course [2,3]. A peculiar characteristic of B19V infection is that not always the virus is cleared and in many cases it can establish persistency in different body tissues [4]. Persistent B19V infection has been observed in immunologically normal individuals [5] including qualified blood donors [6]. The presence of persistent B19V infection in blood donors raises serious questions regarding transfusion safety of the obtained hemoderivatives, especially plasma products and packed erythrocytes.Moreover, B19V is highly resilient to almost all virus inactivation procedures [7], causes infections with a high viral load and these properties predispose to easy viral contamination of the blood products. The relevance of the low B19V load in asymptomatic donors and for the respective recipients of blood is still unclear. Therefore, the objective of this study was to evaluate B19V DNA prevalence and viral load (VL) during 1 month blood collection in a non-metropolitan blood transfusion center in Southeast Brazil (Ribeirão Preto city, Western part of the São Paulo State).Ninety one peripheral blood samples were collected from 91 first time volunteer blood donors (mean age 35.7 years, 18-65 years, 55 % males). All of them were approved on the preliminary interview for blood donation & Svetoslav Nanev Slavov

Introduction: American tripanosomiasis (Chagas disease), the second most neglected disease in the world, is caused by the protozoan parasite Trypanosoma cruzi. Though natural transmission by insect vectors has been controlled, there is significant risk of T. cruzi transmission by blood transfusion in non-endemic regions, generally due to immigration processes from endemic areas. Methodology: The objective of this study was to evaluate anti-T. cruzi seroprevalence in blood donors from the western part of São Paulo State, Brazil, by serologic and immunofluorescence confirmation tests for the period between 2012 and 2014. Currently, this region is regarded as a non-endemic area for Chagas disease. Results: The confirmed overall T. cruzi seroprevalence among blood donors was 0.10%, which can be considered low compared to other Brazilian regions. Nevertheless, the distribution of the anti-T. cruzi antibodies within the examined region was uneven, and some areas of significantly higher prevalence were observed. Conclusions: We could consider two tendencies in the prevalence of T. cruzi: (i) residual older undiagnosed cases from São Paulo State, and (ii) immigration from endemic Brazilian or South American regions. The discordance obtained for T. cruzi prevalence by serologic and immunofluorescence methods demonstrates that more specific routine diagnosis is needed to diminish the cost of the assays and the loss of blood supply once all seropositive blood bags are immediately discarded.