Scale-free dynamics of COVID-19 in a Brazilian city.

A common basis to address the dynamics of directly transmitted infectious diseases, such as COVID-19, are compartmental (or SIR) models. SIR models typically assume homogenous population mixing, a simplification that is convenient but unrealistic. Here we validate an existing model of a scale-free fractal infection process using high-resolution data on COVID-19 spread in São Caetano, Brazil. We find that transmission can be described by a network in which each infectious individual has a small number of susceptible contacts, of the order of 2-5. This model parameter correlated tightly with physical distancing measured by mobile phone data, such that in periods of greater distancing the model recovered a lower average number of contacts, and vice versa. We show that the SIR model is a special case of our scale-free fractal process model in which the parameter that reflects population structure is set at unity, indicating homogeneous mixing. Our more general framework better explained the dynamics of COVID-19 in São Caetano, used fewer parameters than a standard SIR model and accounted for geographically localized clusters of disease. Our model requires further validation in other locations and with other directly transmitted infectious agents.

Identification of bacteriophages in the vagina of pregnant women: a descriptive study.

OBJECTIVE: To determine the presence and identity of extracellular bacteriophage (phage) families, genera and species in the vagina of pregnant women. DESIGN: Descriptive, observational cohort study. SETTING: São Paulo, Brazil. POPULATION: Pregnant women at 21-24 weeks' gestation. METHODS: Vaginal samples from 107 women whose vaginal microbiome and pregnancy outcomes were previously determined were analysed for phages by metagenomic sequencing. MAIN OUTCOME MEASURES: Identification of phage families, genera and species. RESULTS: Phages were detected in 96 (89.7%) of the samples. Six different phage families were identified: Siphoviridae in 69.2%, Myoviridae in 49.5%, Microviridae in 37.4%, Podoviridae in 20.6%, Herelleviridae in 10.3% and Inviridae in 1.9% of the women. Four different phage families were present in 14 women (13.1%), three families in 20 women (18.7%), two families in 31 women (29.1%) and one family in 31 women (29.1%). The most common phage species detected were Bacillus phages in 48 (43.6%), Escherichia phages in 45 (40.9%), Staphylococcus phages in 40 (36.4%), Gokushovirus in 33 (30.0%) and Lactobacillus phages in 29 (26.4%) women. In a preliminary exploratory analysis, there were no associations between a particular phage family, the number of phage families present in the vagina or any particular phage species and either gestational age at delivery or the bacterial community state type present in the vagina. CONCLUSIONS: Multiple phages are present in the vagina of most mid-trimester pregnant women. TWEETABLE ABSTRACT: Bacteriophages are present in the vagina of most pregnant women.

Characterization of HIV risks in a Brazilian sickle cell disease population.

BACKGROUND: A low prevalence of HIV in sickle cell disease (SCD) patients has been reported in the literature though mechanisms for this are not understood. METHODS: HIV risk behaviors were compared between SCD cases and non-SCD controls using a self-administered audio computer-assisted self-interview. SCD cases were recruited from a multi-center SCD cohort established in Brazil; controls were recruited from SCD social contacts. Categorical variables were analyzed using Chi-Square or Fisher exact test. Continuous variables were compared using the Mann-Whitney U test. RESULTS: There were 152 SCD cases and 154 age/location matched controls enrolled at three participating Brazilian centers during 2016-17. No significant differences in number of sexual partners (lifetime or previous 12 months), male-to-male sex partners or intravenous drug use were observed. Cases received more transfusions, surgeries, and acupuncture treatment. CONCLUSIONS: Besides the risk of transfusion-transmitted HIV, which is now exceedingly rare, SCD and non-SCD participants demonstrated similar HIV risk behaviors. Causes other than risk behaviors such as factors inherent to SCD pathophysiology may explain the reported low prevalence of HIV in SCD.

Gut microbiome composition in lean patients with NASH is associated with liver damage independent of caloric intake: A prospective pilot study.

BACKGROUND AND AIM: The aim of the study was to compare the gut microbiomes from obese and lean patients with or without NASH to outline phenotypic differences. METHODS AND RESULTS: We performed a cross-sectional pilot study comprising biopsy-proven NASH patients grouped according to BMI. Microbiome DNA was extracted from stool samples, and PCR amplification was performed using primers for the V4 region of the 16S rRNA gene. The amplicons were sequenced using the Ion PGM Torrent platform, and data were analyzed using QIIME software. Macronutrient consumption was analyzed by a 7-day food record. Liver fibrosis ≥ F2 was associated with increased abundance of Lactobacilli (p = 0.0007). NASH patients showed differences in Faecalibacterium, Ruminococcus, Lactobacillus and Bifidobacterium abundance compared with the control group. Lean NASH patients had a 3-fold lower abundance of Faecalibacterium and Ruminococcus (p = 0.004), obese NASH patients were enriched in Lactobacilli (p = 0.002), and overweight NASH patients had reduced Bifidobacterium (p = 0.018). Moreover, lean NASH patients showed a deficiency in Lactobacillus compared with overweight and obese NASH patients. This group also appeared similar to the control group with regard to gut microbiome alpha diversity. Although there were qualitative differences between lean NASH and overweight/obese NASH, they were not statistically significant (p = 0.618). The study limitations included a small sample size, a food questionnaire that collected only qualitative and semi-quantitative data, and variations in group gender composition that may influence differences in FXR signaling, bile acids metabolism and the composition of gut microbiota. CONCLUSION: Our preliminary finding of a different pathogenetic process in lean NASH patients needs to be confirmed by larger studies, including those with patient populations stratified by sex and dietary habits.

-318C/T polymorphism of the CTLA-4 gene is an independent risk factor for RBC alloimmunization among sickle cell disease patients.

Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) molecule is expressed on T-lymphocyte membrane and negatively influences the antigen-presenting process. Reduced expression of CTLA-4 due to gene polymorphisms is associated with increased risk of autoimmune disorders, whose physiopathology is similar to that of post-transfusion red blood cell (RBC) alloimmunization. Our goal was to evaluate if polymorphisms of CTLA-4 gene that affect protein expression are associated with RBC alloimmunization. This was a case-control study in which 134 sickle cell disease (SCD) patients and 253 non-SCD patients were included. All patients were genotyped for the polymorphisms 49A/G and -318C/T of CTLA-4 gene. The genotype frequency of -318C/T differed significantly between alloimmunized and nonalloimmunized SCD patients, irrespective of clinical confounders (p = .016). SCD patients heterozygous for -318T allele presented higher risk of alloantibody development (OR: 5.4, CI: 1.15-25.6). In conclusion, the polymorphism -318C/T of CTLA-4 gene is associated with RBC alloimmunization among SCD patients. This highlights the role played by CTLA-4 on post-transfusion alloantibody development.

Blood donation in a large urban centre of southeast Brazil: a population-based study.

OBJECTIVES: This study aimed to estimate the prevalence and characterise potential blood donors and non-donors in a well-populated and representative urban area of Southeastern Brazil. BACKGROUND: Studies on blood donation usually evaluate individuals who donate. Population-based studies may contribute to characterise those who never reach the blood centre, trying to increase the range of donors. STUDY DESIGN AND METHODS: This was a secondary analysis of a population-based survey and a blood donor motivation study [Recipient Epidemiology and Donor Evaluation study (REDS II) International]. In a cross-sectional study 4047 individuals representing a metropolitan area answered the question 'Have you ever donated blood at least once in your life?'. The profiles ('Yes/No') were compared. Non-donors from this reference population were compared with donors of a local blood center, in a case control analysis. RESULTS: A total of 69·0% of the population had never donated blood and was composed mostly of women, younger than 30 years old, people not contributing to social security and not subscribing to newspapers. In the case-control study, the likelihood of donating was higher for: men, younger than 50 years old, longer time of education, married, participating in political campaigns and with a good self-perception of health. The factors associated with no blood donation were: self-reported mixed or white race/ethnicity, income higher than two minimum wages and belonging to trade union, political, religious/spiritual, or other social group and worse self perception of health. CONCLUSIONS: This population-based study allowed us to characterise a high proportion of people that never reaches the blood centre. The results may be used to diversify the donor profile, creating strategies to target those least likely to donate blood, as women, white people and those with higher income and purchasing power.

Inflammatory and cardiac biomarkers are differentially expressed in clinical stages of Chagas disease.

BACKGROUND: Chagas disease has a long clinically silent period following Trypanosoma cruzi infection and before development of overt clinical pathology; detectable biomarkers of infection and pathogenesis are urgently needed. We tested 22 biomarkers known to be associated with cardiomyopathy to evaluate if a biomarker signature could successfully classify T. cruzi seropositive subjects into clinical Chagas disease stage groups. METHODS: This cross-sectional retrospective case-control study enrolled T. cruzi seropositive blood donors (BD) who were further characterized as having chronic Chagas cardiomyopathy (CC-BD) or not (nonCC-BD) and seronegative (SN) control donors; we also included clinically diagnosed Chagas cardiomyopathy patients (CC-P). All subjects underwent a health history questionnaire, medical examination, electro- and echocardiograms (ECG and Echo) and phlebotomy. Biomarkers were measured on blinded samples by luminex bead array and Ortho VITROS. RESULTS: A clear biomarker pattern was observed only in more severe cardiac disease; this pattern included significantly elevated levels of inflammatory cytokines IFN-γ, IL-6, IL-10 and TNF-α and soluble cardiovascular disease biomarkers CK-MB, troponin, myoglobin, VCAM and NTproBNP while there were lower levels of MPO, PAI-1, and MCP-1. The markers determined to be the most predictive of disease by ROC curve analysis were NTproBNP and T. cruzi PCR status. CONCLUSIONS: Although many biomarkers demonstrated increased or decreased concentrations among the clinical forms of Chagas disease, NTproBNP and T. cruzi PCR were the only tests that would independently be of clinical value for disease staging, in concert with ECG, Echo and clinical assessments.

Detection of Trypanosoma cruzi DNA in blood by PCR is associated with Chagas cardiomyopathy and disease severity.

BACKGROUND: The significance of detection of Trypanosoma cruzi DNA in blood of antibody-positive patients for risk of development of Chagas heart disease is not well established. The objective of this study was to compare detection of T. cruzi DNA with known clinical and laboratory markers of Chagas cardiomyopathy (CC) severity. METHODS: This is a case-control study nested within a retrospective cohort developed in Brazil to understand the natural history of Chagas disease. The study enrolled 499 T. cruzi seropositive blood donors (SP-BD) and 488 frequency matched seronegative control donors (SN-BD) who had donated between 1996 and 2002, and 101 patients with clinically diagnosed CC. In 2008-2010 all enrolled subjects underwent a health questionnaire, medical examination, electrocardiograms and echocardiograms and polymerase chain reaction (PCR) analyses. A blinded panel of three cardiologists adjudicated the outcome of CC. Trypanosoma cruzi kinetoplast minicircle sequences were amplified by real-time PCR using an assay with a sensitivity of one parasite per 20 mL of blood. All testing was performed on coded samples. RESULTS: Rates of PCR detection of T. cruzi DNA were significantly (P = 0.003) higher in CC patients and SP-BD diagnosed with CC (79/105 [75.2 %]) compared with SP-BD without CC (143/279 [51.3%]). The presence of parasitaemia was significantly associated with known markers of disease progression such as QRS and QT interval duration, lower left ventricular ejection fraction, higher left ventricular index mass, and elevated troponin and NTpro-BNP levels. CONCLUSION: Trypanosoma cruzi PCR positivity is associated with presence and severity of cardiomyopathy, suggesting a direct role of parasite persistence in disease pathogenesis.

Prevalence of Treponema pallidum DNA among blood donors with two different serologic tests profiles for syphilis in São Paulo, Brazil.

The presence of Treponema pallidum DNA was assessed by real-time PCR in samples of blood donors with reactive serologic tests for syphilis. Treponema pallidum DNA was detected in two (1·02%) of 197 samples of VDRL>8, EIA+ and FTA-ABS+ donors, and in no sample from 80 VDRL−, EIA+ and FTA-ABS+ donors. Donors VDRL−, EIA+ and FTA-ABS+ lack demonstrable T. pallidum DNA in their blood and are unlike to transmit syphilis. Donors VDRL>8, EIA+ and FTA-ABS+ carry the risk of syphilis infectivity even in concomitance to antibodies detection. Serologic screening for syphilis may still play a role to prevent its transfusion transmission.

Demographic, risk factors and motivations among blood donors with reactive serologic tests for syphilis in São Paulo, Brazil.

OBJECTIVE: To identify the demographic characteristics, risk factors and motivations for donating among blood donors with reactive serologic tests for syphilis. BACKGROUND: Post-donation interviews with syphilis seropositive blood donors improve recruitment and screening strategies. METHODS: This case-control study compares 75 Venereal Disease Research Laboratory (VDRL) > 8, EIA+ (enzyme immunoassay) and FTA-ABS+ (fluorescent treponemal antibody); 80 VDRL-, EIA+ and FTA-ABS+; and 34 VDRL- and EIA- donors between 2004 and 2009. Donors were assessed by their demographic characteristics, sexual behaviour, history of alcohol and illicit drugs use, and motivations to donate. RESULTS: Donors with VDRL > 8 were more likely to be divorced [AOR = 12·53; 95% confidence interval (CI) 1·30-120·81], to have had more than six sexual partners (AOR=7·1; 95% CI 1·12-44·62) and to report male-male-sex in the past 12 months (AOR=8·18; 95% CI 1·78-37·60). Donors with VDRL-, EIA+ and FTA-ABS+ were less likely to be female (AOR=0·26; 95% CI 0·07-0·96), more likely to be older (AOR=10·2; 95% CI 2·45-42·58 ≥ 39 and <60 years old) and to have had more than six sexual partners in the past 12 months (AOR = 8·37; 95% CI 1·49-46·91). There was no significant difference among groups regarding illicit drugs use; 30·7% (VDRL > 8) and 12·5% (VDRL-, EIA+ and FTA-ABS+) of donors reported that they had been at risk for HIV infection (P = 0·004). One-third of donors came to the blood bank to help a friend or a relative who needed blood. CONCLUSION: Although donors exposed to syphilis reported and recognised some high risk behaviour, most were motivated by direct appeal to donate blood. Monitoring the risk profile of blood donors can benefit public health and improve blood safety.

Knowledge of HIV testing and attitudes towards blood donation at three blood centres in Brazil.

BACKGROUND: Reducing risk of HIV window period transmission requires understanding of donor knowledge and attitudes related to HIV and risk factors. STUDY DESIGN AND METHODS: We conducted a survey of 7635 presenting blood donors at three Brazilian blood centres from 15 October through 20 November 2009. Participants completed a questionnaire on HIV knowledge and attitudes about blood donation. Six questions about blood testing and HIV were evaluated using maximum likelihood chi-square and logistic regression. Test seeking was classified in non-overlapping categories according to answers to one direct and two indirect questions. RESULTS: Overall, respondents were male (64%) repeat donors (67%) between 18 and 49 years old (91%). Nearly 60% believed blood centres use better HIV tests than other places; however, 42% were unaware of the HIV window period. Approximately 50% believed it was appropriate to donate to be tested for HIV, but 67% said it was not acceptable to donate with risk factors even if blood is tested. Logistic regression found that less education, Hemope-Recife blood centre, replacement, potential and self-disclosed test-seeking were associated with less HIV knowledge. CONCLUSION: HIV knowledge related to blood safety remains low among Brazilian blood donors. A subset finds it appropriate to be tested at blood centres and may be unaware of the HIV window period. These donations may impose a significant risk to the safety of the blood supply. Decreasing test-seeking and changing beliefs about the appropriateness of individuals with behavioural risk factors donating blood could reduce the risk of transfusing an infectious unit.

Investigation of human parvovirus B19 occurrence and genetic variability in different leukaemia entities.

Human parvovirus B19V (B19V) has been associated with various haematological disorders, but data on its prevalence in leukaemia are scarce. In this cross-sectional study, we investigated patients in Sao Paulo, Brazil with leukaemia to determine the molecular frequency of B19 variants and characterize the viral genetic variability by partial and complete sequencing of the coding of non-structural protein 1 (NS1)/viral capsid proteins 1 and 2 (VP1/VP2). The presence of B19V infections was investigated by PCR amplification of the viral NS1 gene fragment and confirmed by sequencing analysis. The NS1/VP1/VP2 and partially larger gene fragments of the NS1-positive samples were determined by overlapping nested PCR and direct sequencing results. The B19V NS1 was detected in 40 (16%) of 249 bone marrow samples including 12/78 (15.4%) acute lymphoblastic leukaemia, 25/155 (16.1%) acute myeloid leukaemia and 3/16 (18.7%) chronic myeloid leukaemia samples. Of the 40 participants, 25 (62.5%) were infected with genotype 1a and 15 (37.5%) with genotype 3b. The phylogenetic analysis of other regions revealed that 12/40 (30%) of the patients with leukaemia were co-infected with genotypes 1a and 3b. In addition, a new B19V intergenotypic recombinant (1a/3b) and an NS1 non-recombinant genotype 1a were detected in one patient. Our findings demonstrated a relatively high prevalence of B19V monoinfections and dual infections and provide, for the first time, evidence of inter-genotypic recombination in adults with leukaemia that may contribute to the genetic diversity of B19V and may also be a source of new emerging viral strains with future implications for diagnosis, therapy and efficient vaccine development.

Evaluation of HIV-1 resistance to antiretroviral drugs among 150 patients after six months of therapeutic interruption.

Most of the antiretroviral (ARV) studies in Brazil have been reported in treatment-experienced and naive patients rather than in the setting of treatment interruption (TI). In this study, we analysed reasons given for TI and resistance mutations occurring in 150 HIV-1-infected patients who underwent TI. Of the patients analysed, 110 (73.3%) experienced TI following medical advice, while the remaining patients stopped antiretroviral therapy (ART) of their own accord. The main justifications for TI were: ARV-related toxicities (38.7%), good laboratory parameters (30%) and poor adherence (20%). DNA sequencing of the partial pol gene was successful in 137 (91.3%) patients, of whom 38 (27.7%) presented mutations conferring ARV resistance. A higher viral load prior to TI correlated with drug resistance (P < 0.05). Our results demonstrate that there are diverse rationales for TI and that detection of resistant strains during TI most likely indicates a fitter virus than the wild type. High viral loads coupled with unprotected sex in this group could increase the likelihood of transmission of drug-resistant virus. Thus, treating physicians should be alerted to this problem when the use of ARVs is interrupted.

Torque teno virus (TTV) is prevalent in Brazilian non-human primates and chickens (Gallus gallus domesticus) / Torque teno virus (TTV) es prevalente en primates no humanos brasileños y pollos (Gallus gallus domesticus)

Torque Teno virus (TTV) is an infectious agent of worldwide distribution isolated by the first time as the agent of an acute post-transfusion hepatitis in a patient in Japan. It has been classified into a new floating genus called Anellovirus. Recent studies showed that TTV can also be identified in serum specimens obtained from domesticated farm animals and from non-human primates. To better understand the relationship between TTV and their hosts, a study to detect virus in the serum and whole blood of Brazilian non-human primates and in the plasm of chickens was performed by applying the PCR-UTR-A technique, followed by a genomic sequence and phylogenetic analysis. By nested-PCR-UTR, the DNA of TTV was detected in sera from 4 (5.3 percent) of 75 Cebus apella, 2 (40 percent) of 5 Alouatafusca, 1 (20 percent) of 5 Alouata caraya, 1 (5.2 percent) of 19 Callithrixpenicilata, 1 (4 percent) of 25 Callithrixjacchus, 1 (20 percent) of 5 Saimiri sciureus and 1 (25 percent) of 4 Leontopithecus chrysomelas. Phylogenetic analysis revealed that sequences detected in 8 samples clustered with TTV sequences So-TTV2 (Sagüínus oedipus) and At-TTV3 (Aotes Trivirgatus). Three sequences showed similarity with a human Torque Teno Minivirus (TLMV). TTV ORF2 DNA was detected in one sera sample and one whole blood sample of non-human primates and in one plasm sample of chicken. Phylogenetic analysis revealed that the sequences amplified by the ORF2 region show no difference between human, non-human primates and chicken. This is the first report of TTV in Brazilian new world non-human primates and chicken.

Torque Teno virus (TTV) es una agente infeccioso de distribución mundial, aislado por primera vez como el agente de una hepatitis aguda posterior a la transfusión de un paciente en Japón. Se ha clasificado en un nuevo género flotante llamado Anellovirus. Recientes estudios han demostrado que TTV también puede ser identificado en el suero de especímenes obtenidos desde granjas de animales domésticos y desde primates no humanos. Para entender mejor la relación entre la TTV y sus huéspedes, fue realizado un estudio para detectar el virus en el suero y la sangre de primates no humanos brasileños y en el plasma de pollos mediante la aplicación de la técnica PCR-UTR-A, seguida de una secuencia genómica y análisis filogenético. Por medio de PCR-UTR-anidado, el ADN de TTV fue detectado en sueros de 4 de 75 (5,3 por ciento)Cebus apella, 2 de 5 (40 por ciento) Alouata fusca, 1 de 5 (20 por ciento) de Alouata caraya, 1 de 19 (5,2 por ciento) de Callithrixpenicilata, 1 de 25 (4 por ciento) Callithrixjacchus, 1 de 5 (20 por ciento) de Saimiri sciureus y 1 de 4 (25 por ciento) de Leontopithecus chrysomelas. El análisis filogenético reveló secuencias detectadas en 8 muestras agrupadas con TTV secuencias So-TTV2 (Sagüínus oedipus) y At-TTV3 (Aotes Trivirgatus). Tres secuencias mostraron similitud con el Torque Teno Minivirus humano (TLMV). Fue detectado TTV ORF2 ADN en una muestra de suero y una muestra de sangre de primates no-humanos y en una muestra de plasma de pollo. El análisis filogenético reveló que las secuencias amplificadas por la región ORF2 no muestran ninguna diferencia entre humanos, primates no humanos y pollos. Este es el primer informe de nuevos TTV en primates-no humanos brasileños y en pollos.

Research of torque teno virus (TTV) in serum and total blood of Brazilian non-human primates and in chicken plasma (Gallus gallus domesticus) by the PCR N22 region / Investigación de Torque teno virus (TTV) en suero y sangre de primates no humanos brasileños y en plasma de pollo (Gallus gallus domesticus) por PCR en la region N22

Torque teno virus (TTV) is a recently discovered DNA virus that was originally isolated from a Japanese patient (initials, TT) with post-transfusion hepatitis of unknown aetiology. TTV is an circular DNA virus classified recently together with related Torque teño minivirus, into a new genus called Anellovirus. Infection TTV has been detected in a range of non-human primates as well as domestic animals. The purpose of this study was to search TTV in the serum and total blood of Brazilian monkeys and in plasma of domestic chickens by seminested PCR of coding region (N22), followed by a genomic sequence and phylogenetic analysis. No serum sample was amplified. TTV DNA was detected in total blood from 3 (4 percent) out of 75 brown-capuchin (Cebus apella) and from 1 (25 percent) out of 4 golden-headed lion-tamarin (Leontopithecus chrysomelas). Phylogenetic analysis revealed that one sample showed similarity with one sequence of the cotton top tamarin (Saguinus oedipus) (So-TTV2) and with one of the douroucoulis (ão tes trivirgatus) (At-TTV3). Two samples showed similarity with a human Torque Teño Mini Virus (TLMV). The other sample clustered with one sequence of the chimpanzee (Pt-TTV6) and with the human TTV strain TA278. The plasma chicken samples tested were all negative. The amino acid sequences reported in this study are the first obtained in Brazil from total blood of non-human primates naturally infected by TTV.

Torque teno virus (TTV) es un virus de ADN recientemente descubierto que fue inicialmente aislado de un paciente japonés (iniciales TT) después de la transfusión de hepatitis de etiología desconocida. TTV es un virus de ADN circular recientemente clasificado junto con los torque teno minivirus, en un nuevo género llamado Anellovirus. La infección de TTV se ha detectado en una serie de primates no humanos, así como animales domésticos. El objetivo de este estudio fue buscar TTV en el suero y sangre total de monos de Brasil y en el plasma de pollos domésticos, por seminested PCR de la región de codificación (N22), seguido de una secuencia genómica y el análisis filogenético. Las muestras que no eran suero fueron amplificadas. TTV DNA se detectó en sangre total de 3 (4 por ciento) de un total de 75 capuchinos de cabeza dura (Cebus apella) y de 1 (25 por ciento) de un total de 4 tití- león de cabeza dorada (Leontopithecus chrysomelas). El análisis filogenético demostró que una muestra presentaba similitud con una secuencia de Saguinus Edipo (So-TTV2) y con una de Aotes trivirgatus (A-TTV3). Dos muestras mostraron similitud con un torque teno mini virus (TLMV) humano. La otra muestra agrupada con una secuencia de los chimpancés (PT-TTV6) y con el TTV humanos cepa TA278. El análisis de las muestras de plasma de pollo fueron negativas Las secuencias de aminoácidos que se reportan en este estudio son las primeras obtenidas en Brasil de sangre de primates no humanos infectados naturalmente por TTV.

Human immunodeficiency virus test-seeking motivation in blood donors, São Paulo, Brazil.

BACKGROUND AND OBJECTIVE: Previous studies have shown that volunteer, community-recruited donors have a higher prevalence of human immunodeficiency virus (HIV) infection in São Paulo, Brazil, than replacement donors. One hypothesis which may explain this unexpected finding is that some individuals donate blood because they are seeking HIV testing. The objective of this study was to characterize test-seeking blood donors and to determine whether they are at higher risk for HIV infection compared with other donors. MATERIALS AND METHODS: Subjects presenting for blood donation were asked to participate in a study assessing their motivations (including test seeking) to donate, as measured by perceiving donation as a means to obtain infectious disease test results. Participants completed the standard blood bank predonation screening questions plus our additional survey, and were tested for HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), human T-cell lymphocytotrophic virus (HTLV) I/II, syphilis and Chagas' disease. As a result of anticipated low statistical power to directly measure the association between test-seeking motivation and HIV infection, we tested for herpes simplex virus type 2 (HSV-2) as a marker of sexual risk for HIV. Our survey includes accepted donors as well as persons whose risk-behaviour histories would result in their exclusion from donation according to routine screening procedures. RESULTS: Of 1,720 potential blood donors randomly selected and approached, 1,600 (93.0%) participated. Overall, 141 (8.8%) were classified as test seekers; 15.6% of these were HSV-2 positive. The proportion of test seekers was the same among community-recruited and replacement donors. Test seekers had a higher prevalence of HSV-2 [adjusted odds ratio (AOR) 1.66; 95% confidence interval (CI): 1.06-2.59] adjusting for age, gender and prior donation. The association was significant among community-recruited blood donors whose previous donation was more than 1 year ago (i.e. 'lapsed donors') (AOR 2.55; 95% CI: 1.20-5.44). Test seekers were not more likely to be rejected from blood donation as a result of health reasons, self-reported HIV risk-related behaviour, or by their own confidential unit exclusion. We found no difference in HSV-2 prevalence between persons accepted for donation (15.7%) and those rejected because of self-reported sexual risk (16.7%). CONCLUSIONS: We did not detect a difference in the proportion of test seekers across different types of blood donors; however, we did detect an association between HSV-2 infection and test seeking, especially among community-recruited lapsed blood donors. Of note, questions on test-seeking behaviour detected donors with increased prevalence of HSV-2, but the self-reported sexual risk behaviours currently used for deferral criteria did not. Incentives to get tested at sites other than blood banks may decrease the residual risk of HIV in the blood supply.

DBCollHIV: a database system for collaborative HIV analysis in Brazil

We developed a database system for collaborative HIV analysis (DBCollHIV) in Brazil. The main purpose of our DBCollHIV project was to develop an HIV-integrated database system with analytical bioinformatics tools that would support the needs of Brazilian research groups for data storage and sequence analysis. Whenever authorized by the principal investigator, this system also allows the integration of data from different studies and/or the release of the data to the general public. The development of a database that combines sequences associated with clinical/epidemiological data is difficult without the active support of interdisciplinary investigators. A functional database that securely stores data and helps the investigator to manipulate their sequences before publication would be an attractive tool for investigators depositing their data and collaborating with other groups. DBCollHIV allows investigators to manipulate their own datasets, as well as integrating molecular and clinical HIV data, in an innovative fashion.

Prevalence of GB virus C (hepatitis G virus) and risk factors for infection in São Paulo, Brazil.

The prevalence of GB virus C (GBV-C) varies widely throughout the world. A cross-sectional study was conducted in the city of São Paulo, Brazil, to estimate the prevalence of GBV-C infection and to identify associated risk factors, using a large sampling of the general population rather than blood donors or an illness-related group of subjects. GBV-C RNA was detected by reverse-transcriptase polymerase chain reaction using primers directed to the 5' noncoding region (NCR) and nonstructural 5A region (NS5A) in serum samples from 1,039 healthy individuals 2 years of age or more. Fifty-two individuals were positive for both sets of primers and one was positive for NS5A only (prevalence of GBV-C infection, 5.1%; 95%CI, 3.9-6.7%). No child under 5 years of age was found positive. Among subjects aged 5 years or more, the prevalence of infection increased consistently with age, up to 30-39 years (8.3%), and decreased from then on. The number of sexual partners in the last 3 years (2 or more: OR, 2.6; 95%CI, 1.3-5.5) and history of contact with blood-sucking insects (OR, 2.5; 95%CI 1.2-5.4) were independently associated with GBV-C infection. In conclusion, the prevalence of GBV-C infection is high in São Paulo. In addition to parenteral transmission, another route, e.g. sexual or vertical, may be involved.

Significance of isolated hepatitis B core antibody in blood donors from São Paulo.

The clinical significance of isolated anti-HBc is still a challenge. To elucidate the real importance of this finding in our blood donors, an investigation algorithm was tested. One hundred and twelve isolated anti-HBc seropositive blood donors underwent clinical evaluation and retesting of HBV markers. Those who presented repeatedly reactive isolated anti-HBc, received a single dose of hepatitis B recombinant vaccine to verify anti-HBs early response. A HBV-DNA determination by PCR was done for those who did not test positive to anti-HBs after vaccine. The level of anti-HBc was recorded as a ratio of the sample-to-cut-off values (S:C ratio) in 57 candidates at donation. Comparing true and false-positive anti-HBc results, the different S:C ratios of them were statistically significant and when less than 2, implying in a false-positive result probability over 80%. A high percent of false-positive results (16.07%) was verified after anti-HBc retesting. HBV immunity was characterized in 49.11%, either by anti-HBs detection in retesting (15.18%), or after a single dose HBV vaccination (33.93%). HBV-DNA was negative in all tested donors. In conclusion, this algorithm was useful to clarify the meaning of isolated anti-HBc in most of our blood donors.