Vanusa Pousada da Hora

HIV-1 subtype C dissemination in southern Brazil

Objectives:To describe the molecular and epidemiological profile of HIV-1 in patients followed at the University Hospital of Rio Grande, Brazil. Design and methods:A cross-sectional study was conducted from September to December 2002. Plasma viral RNA of 85 patients was extracted and protease and reverse transcriptase genes were polymerase chain reaction-amplified and sequenced. Sequences were subtyped and examined to antiretroviral resistance mutations. Laboratory data and past history of antiretroviral treatment were also collected. Results:Most viruses were either subtype B (42%) or subtype C (45%). No risk behaviour, sexual orientation or laboratory parameter was associated with any specific subtype, but subtype C tended to be more frequently found in women (P = 0.06). The prevalence of subtype C has increased over the HIV/AIDS epidemic, accounting for almost 60% of cases diagnosed in 2002. Intra-subtype genetic distances were smaller in subtype C than in subtype B, suggesting a more recent introduction of the former in the epidemic. Of patients under treatment, 60% had at least one antiretroviral drug resistance mutation, but no mutation was specifically associated with any HIV-1 subtype. Only one resistance mutation each was found in drug-naive patients with subtypes B and C. Conclusion:Despite the fact that subtype C appeared in southern Brazil more recently than subtype B, it is now the predominant strain in Rio Grande. The epidemic spread of subtype C could be taking place in Brazil, and possibly in south America, a phenomenon similar to that seen in other countries where this subtype is now totally dominant.

Non-toxic derivatives of LT as potent adjuvants.

The heat-labile enterotoxin of Escherichia coli (LT) consists of an enzymatically active A subunit (LTA) and a pentameric B subunit (LTB). LT has been extensively studied as a potent modulator of immune responses but wild-type LT is toxic and therefore unsuitable for clinical use. Approaches pursued to avoid the toxicity associated with the use of the native toxin while retaining its adjuvant properties have included isolation of subunit B (LTB) and construction of non-toxic LT AB complex mutants, such as LTK63 mutant. Here we review the immunomodulatory characteristics of LTB and LTK63 and their potential as mucosal and parenteral vaccine adjuvants.

High-throughput multi-parameter flow-cytometric analysis from micro-quantities of Plasmodium-infected blood

Despite significant technological and conceptual advances over the last century, evaluation of the efficacy of anti-malarial vaccines or drugs continues to rely principally on direct microscopic visualisation of parasites on thick and/or thin Giemsa-stained blood smears. This requires technical expertise of the microscopist, is highly subjective and error-prone, and does not account for aberrations such as anaemia. Many published methods have shown that flow cytometric analysis of blood is a highly versatile method that can readily detect nucleic acid-stained parasitised red blood cells within cultured cell populations and in ex-vivo samples. However several impediments, including the difficulty in distinguishing reticulocytes from infected red blood cells and the fickle nature of red blood cells, have precluded the development and universal adoption of flow-cytometric based assays for ex-vivo sample analysis. We have developed a novel high-throughput assay for the flow cytometric assessment of blood that overcomes these impediments by utilising the unique properties of the nucleic acid stain DAPI to differentially stain RNA and DNA, combined with novel fixation and analysis protocols. The assay allows the rapid and reliable analysis of multiple parameters from micro-volumes of blood, including: parasitaemia, platelet count, reticulocyte count, normocyte count, white blood cell count and delineation of subsets and phenotypic markers including, but not limited to, CD4(+) and CD8(+) T cells, and the expression of phenotypic markers such as PD-L1 or intracellular cytokines. The assay requires less than one drop of blood and is therefore suitable for short interval time-course experiments and allows the progression of infection and immune responses to be closely monitored in the laboratory or cytometer-equipped field locations. Herein, we describe the technique and demonstrate its application in vaccinology and with a range of rodent and human parasite species including Plasmodium yoelii, Plasmodium chabaudi, Plasmodium berghei and Plasmodium falciparum.

Determinants of HIV-1 mother-to-child transmission in Southern Brazil

Different human immunodeficiency virus type 1 (HIV-1) subtypes may have distinct biological, immunological and pathogenic properties. Efficiency of mother-to-child transmission (MTCT) may be among those properties, but few and controversial results have been described so far. In this study, 102 children born from HIV-1-infected mothers between 1998 and 2004 in the city of Rio Grande, Brazil were analyzed for potential risk factors associated with MTCT. That geographic region is characterized by a high proportion of subtype C-infected subjects, and it allowed comparison between subtypes B and C and their influence on MTCT. The analysis also included clinical, obstetric and immunological parameters. Multivariate regression analyses were conducted to evaluate the influence of the parameters on MTCT, and prevalence ratios (PR) and 95% confidence intervals (CI95) were also calculated. A surprisingly high prevalence of subtype C of over 70% was found. Only the HIV viral load and the use of ACTG 076 protocol were predictive of MTCT. HIV subtype and CD4 T-cell counts were not associated with increased risk of transmission. Although a clear expansion of subtype C is evident in southern Brazil, it does not seem to correlate with increased risk of vertical transmission.

Seroepidemiology of Paracoccidioides brasiliensis infection in horses from Rio Grande do Sul, Brazil

Paracoccidioides brasiliensis is the etiological agent of the major systemic mycosis in Brazil, called paracoccidioidomycosis. Although the Rio Grande do Sul is considered an endemic area of the disease, there are few studies on the ecology of P. brasiliensis in the state. Therefore, this study aimed to evaluate the infection of P. brasiliensis in horses from the mesoregion of Southwest Riograndense, using these animals as sentinels. Serological techniques, such as double immunodiffusion in agar gel (AGID) and indirect ELISA, were performed to detect the anti-gp43 P. brasiliensis antibody in horses from five different farms in the region of Bagé, RS, Brazil. Serology was performed in 200 Pure Blood English horses up to two years of age that were born and raised exclusively at the farms. Of these horses, 12% had anti-gp43 antibodies according to the ELISA results, with rates ranging from 0 to 30% according to the farm of origin (p < 0.001). Based on the immunodiffusion results, all equine serum samples were negative. These results indicate the presence of the fungus P. brasiliensis in the middle region of the southwestern state of Rio Grande do Sul, Brazil.

PREVALENCE OF HERPES SIMPLEX VIRUS TYPE 2 AND RISK FACTORS ASSOCIATED WITH THIS INFECTION IN WOMEN IN SOUTHERN BRAZIL

SUMMARY The herpes simplex virus type 2 (HVS-2) is the most prevalent infection worldwide. It is a cofactor in the acquisition of human immunodeficiency virus (HIV) and the persistence of human papillomavirus (HPV). This study evaluated the prevalence of HSV-2, using the polymerase chain reaction (PCR), and associated factors in patients treated at the Federal University of Rio Grande (FURG) and Basic Health Units (BHU) in Rio Grande, Brazil. The observed prevalence of HSV-2 was 15.6%. Among the 302 women studied, 158 had received assistance in BHU and 144 were treated at FURG. The prevalence of HSV-2 in these groups was 10.8% and 20.8%, respectively, RR 1.9 and p = 0.012. Knowledge about the Pap smear, and the presence of lesions showed no association with HSV-2 infection. Multivariate analysis showed that the variable that most influenced the risk of HSV-2 infection was the presence of HIV infection, with a relative risk of 1.9 and p = 0.04. Discussion: Genital ulcers are an important entry point for HIV, and condom use is an important strategy to reduce transmission of HIV and HSV-2.

Evaluation of factors associated with vertical HIV-1 transmission

Objective To compare the prevalence and factors associated with vertical transmission of human immunodeficiency virus 1 (HIV–1) among pregnant women treated in the periods of 1998–2004 and 2005–2011 in a reference service for the care of HIV-infected patients in southern Brazil.OBJECTIVE To compare the prevalence and factors associated with vertical transmission of human immunodeficiency virus 1 (HIV-1) among pregnant women treated in the periods of 1998-2004 and 2005-2011 in a reference service for the care of HIV-infected patients in southern Brazil. METHODS This was a descriptive and analytical study that used the databases of laboratories from the CD4 and STDs/AIDS Viral Load National Laboratory Network of the Brazilian Ministry of Health. HIV-1-infected pregnant women were selected after an active search for clinical information and obstetric and neonatal data from their medical records between the years of 1998 and 2011. RESULTS 102 pregnant women were analyzed between 1998 and 2004 and 251 in the period between 2005 and 2011, totaling 353 children born to pregnant women with HIV-1. It was observed that the vertical transmission rate was 11.8% between 1998 and 2004 and 3.2% between 2005 and 2011 (p<0.001). The increased use of antiretroviral drugs (p=0.02), the decrease in viral load (p<0.001), and time of membrane rupture lower than 4h (p<0.001) were associated with the decrease of vertical transmission factors when comparing the two periods. CONCLUSION It was observed a decrease in the rate of vertical transmission in recent years. According to the studied variables, is suggested that the risk factors for vertical transmission of HIV-1 were absence of antiretroviral therapy, high viral load in the pregnant women, and membrane rupture time >4h.

Prevalence of herpes simplex virus types 1 and 2 at maternal and fetal sides of the placenta in asymptomatic pregnant women

Herpes simplex virus 1 (HSV‐1) commonly causes orolabial infection, but can also infect the genital mucosa. In contrast, HSV‐2 is usually genital. Genital herpes can transmit the virus vertically to the fetus during pregnancy. We sought to estimate the prevalence of HSV‐1/2 on the maternal and fetal sides of the placenta.

Original articleEvaluation of factors associated with vertical HIV-1 transmissionAvaliação dos fatores associados à transmissão vertical de HIV-1☆

Objective To compare the prevalence and factors associated with vertical transmission of human immunodeficiency virus 1 (HIV–1) among pregnant women treated in the periods of 1998–2004 and 2005–2011 in a reference service for the care of HIV-infected patients in southern Brazil.OBJECTIVE To compare the prevalence and factors associated with vertical transmission of human immunodeficiency virus 1 (HIV-1) among pregnant women treated in the periods of 1998-2004 and 2005-2011 in a reference service for the care of HIV-infected patients in southern Brazil. METHODS This was a descriptive and analytical study that used the databases of laboratories from the CD4 and STDs/AIDS Viral Load National Laboratory Network of the Brazilian Ministry of Health. HIV-1-infected pregnant women were selected after an active search for clinical information and obstetric and neonatal data from their medical records between the years of 1998 and 2011. RESULTS 102 pregnant women were analyzed between 1998 and 2004 and 251 in the period between 2005 and 2011, totaling 353 children born to pregnant women with HIV-1. It was observed that the vertical transmission rate was 11.8% between 1998 and 2004 and 3.2% between 2005 and 2011 (p<0.001). The increased use of antiretroviral drugs (p=0.02), the decrease in viral load (p<0.001), and time of membrane rupture lower than 4h (p<0.001) were associated with the decrease of vertical transmission factors when comparing the two periods. CONCLUSION It was observed a decrease in the rate of vertical transmission in recent years. According to the studied variables, is suggested that the risk factors for vertical transmission of HIV-1 were absence of antiretroviral therapy, high viral load in the pregnant women, and membrane rupture time >4h.

Prevalence and vertical transmission of human pegivirus among pregnant women infected with HIV

To determine the prevalence of human pegivirus (HPgV) and factors associated with vertical transmission among pregnant women infected with HIV.