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Transfusion-transmitted viruses count among the greatest threats to blood safety. In Argentina, current laws oblige testing all donated blood for the presence of antibodies against human T-cell lymphotropic viruses 1 and 2 (HTLV-1/2). In endemic zones of the country, a high rate of seronegative HTLV-1 individuals with clear evidence of infection because of symptoms and/or presence of tax sequences of HTLV-1 and/or IgG anti-Tax antibodies has been recently described. Migration from endemic to nonendemic zones of Argentina is very frequent.During a 1-year period, in the blood bank of Córdoba city, we performed molecular screening of all donors who were born in or arose from endemic zones for HTLV-1/2 in Argentina and neighbouring countries.By screening 219 bp of HTLV-1/2 tax gene, 0.6% (2/317) of the blood donors proved to be positive for HTLV-1 tax sequence. One of the donors presented anti-Tax antibodies, demonstrating the transcriptional activity of the tax gene, and the other donor was also positive for LTR and pol gene sequences. The HTLV-1 genetic analysis of the LTR sequence determined that it belonged to the Cosmopolitan subtype HTLV-1aA.These findings suggest potential limitations of some currently approved screening assays for HTLV-1 detection applied in some donor populations and the possibility of an HTLV-1 seronegative carrier state with the potential for silent transmission by blood.

Universal vaccination is the most effective strategy to control hepatitis B virus (HBV) infection. In Argentina, vaccination against HBV was incorporated in year 2000 for newborns and in 2003 for 11 years old children. However, there is a paucity of data about protection levels against HBV infection. The aim of this work was to determine the prevalence of seroprotective anti-HBs antibodies (aHBs) in Argentina. Serum samples negative for HBsAg and anti-HBc from 132 children born after year 2000 and 762 blood donors, older than 18 years, from five centers across the country, were analyzed for aHBs. Titers ¡Ý10 mIU/mL were observed in 74/132 children (56.1%) and 336/762 (44.1%) in blood donors. The median age for blood donors was 33.9 (23¨C43); from them, 210 (27.6%) were born after 1992 and, therefore, were catch-up by vaccine implementation at 11 years old age. Donors born in 1992 or before showed a significantly lower frequency of protection (32.2%) compared to donors born after 1992 (75.2%), p < 0.0001. In addition, significant differences were observed in the status of seroprotection between different participating centers (p = 0.024). Implementation of HBV vaccine in 2000 and 2003 implied an overall increase of the aHBs seroprotective rates, with a particularly adequate response in children vaccinated at 11 years old age. The observed results suggest that population born in 1992 or before is currently the most susceptible. Consequently, it would be advisable to become aware of the risk of transmission in this age group and to stress this population vaccination campaigns. Fil: Di Lello, Federico Alejandro. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Blejer, Jorgelina L.. Fundación Hemocentro; Argentina Fil: Alter, Adriana. Fundación Hemocentro; Argentina Fil: Bartoli, Sonia. Centro Regional de Hemoterapia Jujuy; Argentina Fil: Vargas, Fabiana Alejandra. Centro Regional de Hemoterapia de Mendoza; Argentina Fil: Ruiz, Rosángela. Hospital Regional Rio Grande; Argentina Fil: Galli, Claudio. Hospital Regional Rio Grande; Argentina Fil: Blanco, Sebastian. Universidad Nacional de Córdoba. Facultad de Medicina; Argentina. Fundación Banco Central de Sangre; Argentina Fil: Gallego, Sandra Veronica. Fundación Banco Central de Sangre; Argentina. Universidad Nacional de Córdoba. Facultad de Medicina; Argentina Fil: Fernández, Roberto. Fundación Hemocentro; Argentina Fil: Martínez, Alfredo P.. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; Argentina Fil: Flichman, Diego Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina

Heterologous vaccination against coronavirus disease 2019 (COVID-19) provides a rational strategy to rapidly increase vaccination coverage in many regions of the world. Although data regarding messenger RNA (mRNA) and ChAdOx1 vaccine combinations are available, there is limited information about the combination of these platforms with other vaccines widely used in developing countries, such as BBIBP-CorV and Sputnik V. Here, we assess the immunogenicity and reactogenicity of 15 vaccine combinations in 1,314 participants. We evaluate immunoglobulin G (IgG) anti-spike response and virus neutralizing titers and observe that a number of heterologous vaccine combinations are equivalent or superior to homologous schemes. For all cohorts in this study, the highest antibody response is induced by mRNA-1273 as the second dose. No serious adverse events are detected in any of the schedules analyzed. Our observations provide rational support for the use of different vaccine combinations to achieve wide vaccine coverage in the shortest possible time.

Here we document the behavior at wall scale of a hemp-based hygroscopic material under various temperature and moisture dynamic conditions. The wall was made of precast hemp concrete (HC) blocks with air cavities. It was tested within a bi-climatic chamber and monitored thanks to hygrothermal sensors in the wall and in the chambers. The results from an in-house heat and moisture transfer model were compared to the experimental data, using the actual thermal and hygric characteristics of the hemp-based material determined in a previous study. The experiments allowed to demonstrate how the heat and moisture transport phenomena within the wall are coupled, particularly how a temperature difference can be a sufficient driving force for the release of moisture. The work points out the impact of moisture adsorption on heat release and on the temperature changes within the wall. Finally the numerical model served also to the modelling of an equivalent wall made of concrete to help highlighting the moisture dumping capability of the bio-based material, together with its thermal insulation capacity.

Background: The safety, efficacy and humoral immune-response to Sputnik-V were independently evaluated. Since SARS-CoV-2 lineage P.1 is rapidly spreading in Argentina and the neutralization of P.1 by Sputnik-V-elicited sera has not been determined yet, we evaluated efficacy of Sputnik-V-immunized humoral response faced to P.1. Methods: The safety/efficacy of Sputnik-V were assessed by monitoring self-reported adverse events and disease rate among Health-Care Workers (HCW) who received both doses, within 4 months. Immunogenicity of the vaccine was evaluated by measuring anti-Spike (S) IgG antibodies (Abs) and neutralizing antibodies (NAb) prior to, 14 and 42 days after-vaccination. To determine the effectiveness of pre-existing NAb against P.1, samples were analysed from individuals: A-recovered from SARS-CoV-2 wild type B.1 (WT) infection, B-recovered from WT infection and received one/two doses of Sputnik-V, and C-without previous infection and received one/two doses of Sputnik-V. Findings: A total of 285 HCW were recruited, all reporting good tolerance, without severe adverse events. Sputnik showed 97·60% efficacy against COVID-19 during the observation period. At day 42, 99·65% of the individuals had anti-S IgG; however, 23·15% had not detectable NAb. The NAb ability against the SARS-CoV-2 strains showed significantly higher neutralization levels against WT compared to P.1 (p

BACKGROUND Hepatitis E virus (HEV) is the main cause of enteric acute viral hepatitis worldwide. In this epidemiological framework, it has become a threat to blood safety and a relevant issue for blood transfusions. However, there is a paucity of data regarding prevalence of HEV infection. The aim of this study was to determine HEV seroprevalence in blood donors from different regions from Argentina. MATERIAL AND METHODS Serum samples from 391 individuals attending five blood donor centers located in different regions from Argentina were analyzed for anti-HEV IgG and anti-HEV IgM. RESULTS Overall, anti-HEV IgG was detected in 44 out of 391 (11.3%) samples. HEV prevalence ranged from 5.1 to 20.0% among different country regions. A significant difference in blood donors' age was observed between anti-HEV IgG positive and negative individuals [44 (37-51) vs. 35 (27-43), P

A retrospective, cross-sectional study was conducted to determine the frequency of human parvovirus B19 (B19V) infected individuals, viral loads and immunity among blood donors from Argentina, in a post-epidemic outbreak period. B19V DNA and specific IgG were tested in minimum study samples of donors attending a blood bank at Córdoba, Argentina, in 2014. Anti-B19V IgM and viral loads were determined in B19V-positive plasma samples. Seven of 731 samples (0.96%) resulted positive, corresponding to individuals aged 32–53 years, four of them repeat donnors and three first-time donors. Viral loads were, Health sciences; Infectious disease; Virology; Laboratory medicine; Biomarkers; Human erythroparvovirus B19; Blood donor; Blood safety; Persistent infection; Argentina.

In some areas of Argentina endemic for human T-lymphotropic virus type 1 (HTLV-1), tropical spastic paraparesis is frequent in subjects who lack antibodies against the virus; however, the relevance of this seronegative status in the country has not been investigated. In neighboring countries, HTLV-1 seronegative status has been described in patients with different diseases; however, data regarding features of seronegative HTLV-1 carriers are scarce. We investigated the seronegative status in 124 relatives of 28 HTLV-1 infected subjects from an endemic area in Northwest Argentina. Blood samples and clinical/epidemiological data were collected. Human T-lymphotropic virus type 1 infection was diagnosed by serology and long terminal repeat (LTR) sequence, env and tax gene detection. IgG anti-Tax HTLV-1 antibody, tax gene sequence, and DNA proviral load were also evaluated. Seventy-five percent of the 124 relatives were negative for HTLV-1/2 antibodies; 35.5% were also negative by molecular assays and 64.5% were negative for HTLV-1 LTR and env sequences, but positive for two sequences of HTLV-1 tax gene. Also, 35.7% of these subjects had IgG anti-Tax antibodies. The seronegative HTLV-1 status was significantly associated with male gender, youth, and sensory symptoms/autonomic nervous system dysfunction. High rates of seronegative symptomatic and asymptomatic HTLV-1 carriers in Argentina are described. The evidence highlights that HTLV-1 prevalence may be underestimated worldwide. Larger cohort studies are required to assess disease outcome in these seronegative subjects. Also, the findings emphasize the limitations of ongoing screening assays for diagnosis and blood safety. Therefore, algorithms for HTLV-1 diagnosis should include not only serological but also molecular assays. Fil: Gallego, Sandra Veronica. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología Dr. J. M. Vanella; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Frutos, Maria Celia. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología Dr. J. M. Vanella; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Blanco, Sebastian. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología Dr. J. M. Vanella; Argentina Fil: Castro, Gonzalo. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología Dr. J. M. Vanella; Argentina Fil: Balangero, Marcos Cesar. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología Dr. J. M. Vanella; Argentina Fil: Panigo, David Elías. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Matemáticas; Argentina Fil: Mangeaud, Arnaldo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Matemáticas; Argentina Fil: Remondegui, Carlos. Hospital San Roque. Servicio de Infectología y Enfermedades Tropicales; Argentina Fil: Rocha, Anderson Santos. Universidad Federal de Minas Gerais. Instituto de Ciencias Biológicas. Departamento de Microbiología. Laboratorio de Virología Básica y Aplicada; Brasil. Interdisciplinary HTLV Research Group; Brasil Fil: Franco, Gabriela Melo. Universidad Federal de Minas Gerais. Instituto de Ciencias Biológicas. Departamento de Microbiología. Laboratorio de Virología Básica y Aplicada; Brasil. Interdisciplinary HTLV Research Group; Brasil Fil: Martins, Marina Lobato. Interdisciplinary HTLV Research Group; Brasil Fil: Barbosa Stancioli, Edel Figueiredo. Universidad Federal de Minas Gerais. Instituto de Ciencias Biológicas. Departamento de Microbiología. Laboratorio de Virología Básica y Aplicada; Brasil. Interdisciplinary HTLV Research Group; Brasil Fil: Nates, Silvia Viviana. Universidad Nacional de Córdoba. Facultad de Medicina. Instituto de Virología Dr. J. M. Vanella; Argentina

This study describes the prevalence of HBV infection based on detection of HBsAg and HBV-DNA by NAT in 70,102 blood donors in Argentina (Córdoba province) and shows the viral genotype distribution and frequency of occult HBV infection (OBI) in this population. Forty-two donors were confirmed positive for HBV infection (0.06 %), and four had OBI. Genotype F was the most prevalent (71.4 %), followed by A (14.3 %), C (7.1 %) and D (7.1 %). This is the first report of the prevalence of confirmed HBV infection and the high frequency of occult HBV infection in a blood bank in Argentina.

ResumenCon el objetivo de reducir el número de resultados falsos reactivos al determinar los anticuerpos contra HTLV-1/2, se evaluaron algoritmos alternativos. De 20 210 muestras estudiadas, el 0,37 % (74/20 210) fueron reactivas por ELISA Murex Abbott. De estas, 23 se confirmaron positivas por inmunofluorescencia indirecta y 51 fueron negativas; valor predictivo positivo (VPP) 31,08 %. Al combinar ELISA Murex con aglutinación de partículas de gelatina (AP) y con ELISA MP, se obtuvieron los siguientes resultados: 26/74 resultaron reactivas por Murex y AP, VPP 88,5 %, y 32/74 reactivas con Murex y ELISA MP, VPP 71,8 %. Del análisis de la curva ROC se determinó que para un valor de RP de 4,74 por Murex, la sensibilidad, la especificidad, el VPP y el VPN son 100 %, 98,04 %, 95,8 % y 100 %, respectivamente. Proponemos que las muestras reactivas por ELISA Murex con RP ≤ 4,74 sean retesteadas por duplicado por AP, y que las que resulten concordantemente no reactivas sean definidas como negativas para HTLV-1/2.AbstractAlternative algorithms were evaluated in order to reduce the number of false reactive results for antibodies against HTLV-1/2. From 20,210 samples tested, 0.37% (74/20,210) was reactive by ELISA Murex. Of these, 23 were confirmed as positive by the indirect immunofluorescence assay whereas 51 were negative, being the positive predictive value (PPV) 31.08%. From a combination of the ELISA Murex assay with the particle agglutination assay (PA) and ELISA MP, the following results were obtained: 26/74 were reactive by ELISA Murex and PA, PPV 88.5% and 32/74 were reactive by ELISA Murex and ELISA MP, PPV 71.8%. The ROC curve analysis determined that for an RP 4.74, the values for sensitivity, specificity, PPV and NPV by ELISA Murex were 100%, 98.04%, 95.8% and 100%, respectively. We propose that reactive samples by ELISA Murex with an RP ≤ 4.74 should be retested in duplicate by PA, and the resulting concordantly nonreactive samples should be defined as negative for HTLV-1/2.

Resumen Las peritonitis son la complicacion mas frecuente en pacientes en dialisis peritoneal, llevando en muchas ocasiones al abandono de la tecnica. Los microorganismos mas habituales son Streptoccocus, Staphyloccocus y algunos germenes gram-negativos. Son raros los casos de peritonitis producidas por Pasteurella, generalmente Pasteurella multocida, aunque el aumento en el numero de animales domesticos en nuestra sociedad hace que las zoonosis tengan un papel cada vez mas relevante. Describimos aqui el primer caso de peritonitis por Pasteurella canis en un paciente en dialisis peritoneal y hacemos una revision de todas las referencias bibliograficas de peritonitis por Pasteurella en pacientes en dialisis peritoneal.

The oncoprotein Tax was characterized genetically from a large cohort of human T-cell lymphotropic virus type 1 (HTLV-1) seropositive individuals from the most endemic region of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and HTLV-1 infection in Argentina, the province of San Salvador de Jujuy. Sixteen HAM/TSP patients and 47 HTLV-1 healthy carriers were evaluated. Six Tax genetic polymorphisms were identified and observed in 70.8% of healthy carriers and 62.5% of HAM/TSP patients. Tax genetic polymorphisms were not associated with clinical status but A8344C polymorphism statistically provide a borderline protective effect of HAM/TSP outcome. Nucleotide diversity in healthy carriers was 0.00549, whereas HAM/TSP virus population revealed a low diversity of 0.00379, suggests a positive selection for Tax protein conservation in this group. It is concluded that tax genetic polymorphisms do not increase the risk of developing HAM/TSP in this endemic region. However, in spite of the low prevalence of HTLV-1aB genotype, statistical analysis revealed an important correlation of tax genetic signatures with HTLV-1aA trans-continental subgroup.

Resumen Introduccion La hemodialisis supone la primera opcion de tratamiento renal sustitutivo en pacientes incidentes y la segunda, tras el trasplante renal, en pacientes prevalentes. Para su realizacion es imprescindible un acceso vascular que garantice una tecnica adecuada. Con el objetivo de conocer la situacion de los accesos vasculares en nuestra poblacion en hemodialisis, comparandola con otras areas geograficas, y de valorar el cumplimiento de las recomendaciones de las guias clinicas, realizamos un estudio retrospectivo y descriptivo referente al ano 2007 en nuestra provincia. Material y metodos Revisamos los accesos vasculares de los pacientes que iniciaron hemodialisis en nuestra provincia en 2007 y aquel a traves del cual se dializaban a 31 de diciembre de 2007. Realizamos un analisis comparativo con la situacion en Espana, Europa y EE.UU., y valoramos el grado de cumplimiento de los objetivos que recomiendan las actuales guias del acceso vascular en Espana y las guias K/DOQI. Resultados 45 pacientes comenzaron hemodialisis, 28 (62,2%) disponian de acceso vascular permanente: 24 (53%) fistulas autologas, 3 (7%) protesis y 1 (2%) cateter tunelizado, y 17 (37,8%) carecian de este. A 31 de diciembre de 2007, 185 pacientes realizaban hemodialisis, 43 en el hospital y 142 en centros perifericos, a traves de los siguientes accesos vasculares: 139 (75%) fistulas autologas, 13 (7%) protesis, 23 (12%) cateteres permanentes y 10 (6%) transitorios. La situacion varia entre el hospital con mayor porcentaje de cateteres y los centros perifericos, donde el porcentaje de fistulas autologas es superior. Conclusiones La situacion del acceso vascular en nuestra provincia dista de ser ideal, con un alto porcentaje de pacientes que inician hemodialisis a traves de cateteres transitorios, que ademas permanecen insertos por periodos muy prolongados. Dentro de los accesos definitivos, el porcentaje de fistulas nativas y la tasa de cateteres permanentes son aceptables, aunque no alcanzan las recomendaciones actuales.

The province of San Salvador de Jujuy, located in the northwest of Argentina, is a highly endemic area for HTLV-1 infection and a foci of tropical spastic paraparesis/HTLV-1-associated myelopathy (HAM/TSP). Therefore, to better understand this, we carried out a genetic characterization of a large set of HTLV-1 strains (n = 65) of descendants of Amerindians from this region. The LTR and env regions were analyzed. The genetic analysis showed that all of these new HTLV-1 isolates from Argentina belong to the Transcontinental subgroup A of the HTLV-1a Cosmopolitan subtype, with the exception of three isolates that cluster within the Japanese subgroup B. Interestingly, the majority of the sequences from Jujuy province belonged to a distinct cluster within the Latin America Transcontinental subgroup, referred to here as the Jujuy subcluster, and were characterized by specific signatures in the LTR. Given that the samples analyzed in this study belong to the Amerindian population and the high prevalence of HTLV-1 in Jujuy in contrast to the low prevalence of this virus in the country, it could be that HTLV-1aA was spread in Argentina from the Amerindians to the cosmopolitan population. Moreover, this is the first report of an HTLV-1aB or Japanese subgroup in descendants of non-Japanese people in South America.

This study shows first data on HTLV-1/2 seroprevalence among pregnant women in the non-endemic region of Argentina. In a retrospective study a representative sample (n = 3,143) of the pregnant women registered in the health public service in the province of Córdoba was evaluated. HTLV-1/2 seroprevalence was 0.191% +/- 0.0857 [IC 0.022-0.359]. This prevalence was 10 times higher in pregnant women than in blood donors [0.019 (4/21.183)]. The pregnant women would reflect the epidemiology of the general population more accurately since it constitutes a more heterogeneous group than that of blood donors. The prevalence of infection with HIV was 2.8 times higher than that of HTLV-1/2 (P0.05) and the presence of any of these two viruses was not a subrogating indicator of the presence of the other (Goodman and Kruskal's Tau coefficient = 0.0092). The prevalence of HBV was not significantly different from that of HTLV-1/2 (P0.05). We consider that it is necessary to carry out continuous studies in order to define the main risk factors for infection of these women. Thus, a decision could be made to apply the best policy in public health to prevent vertical transmission of the virus in Argentina.

p12 pX ORF-I (p12I) of simian T cell lymphotropic virus 1 from Central and West Africa is a 91-amino acid (aa) protein, contrasting with the known p12 sequences from human T cell lymphotropic virus type 1, which are 99 aa in length. An in silico sequence analysis shows a premature termination codon in HTLV-1 p12I sequences from South American and Japanese strains. A translation analysis indicated the presence of 86-aa and 81-aa p12I proteins, shorter than the 99-aa protein found in the majority of HTLV-1 strains around the world. This report shows one more common feature between these two viruses. Additionally, the HTLV-1 p12 signature reported as a genetic marker of Brazilian sequences (p12I P63 and P91) is also highly prevalent in p12 Argentinean sequences. Because p12I may confer a proliferative advantage on HTLV-1-infected cells the existence of naturally truncated proteins might supply insights into its pathogenic mechanisms.

In this report the results of seroepidemiologic studies of human T-lymphotropic virus type I (HTLV-I) and type II (HTLV-II) infections in different population groups in Argentina have been compiled. The studies have shown a high prevalence of HTLV-I/II infection in blood donors in the provinces in the north of Argentina (1.0% in Jujuy 0.7% in Salta and 0.6% in Formosa) and a low prevalence in the provinces in the central region of the country (=0.1%). High rates of HTLV-I (0.45%–2.78%) and HTLV-II (2.78%–21.9%) infections have been documented in Native Indian groups and have highlighted the importance of sexual and mother-to-child transmission of the viruses. The presence of HTLV-I/II antibodies in HIV-infected individuals indicates that both viruses are circulating in certain high-risk population groups. HTLV-I/II was detected in intravenous drug users (2.56%–21.7%) homosexual men (0.5–1.33%) prostitutes (0.8%) and hemophiliacs (2.8%). In conclusion HTLV-I/II infection is circulating in low- and high-risk populations in Argentina and these findings would support the view that selective screening for HTLVI/ II should be implemented to reduce the spread of infection. (authors)

Background Molecular and epidemiological studies of transmission routes and risk factors for infection by HTLV-1 are extremely important in order to implement control measures, especially because of the high prevalence of HTLV-1 in several regions of the world. San Salvador de Jujuy, Northwest Argentina, is a highly endemic area for HTLV-1 and foci of tropical spastic paraparesis/HTLV-1-associated myelopathy. Objective To gain further insight into the role of intrafamilial transmission of HTLV-1 in a highly endemic region in Argentina. Method Cross-sectional study in Northwest Argentina. Epidemiological data and blood samples were collected from 28 HTLV-1 infected subjects (index cases) and 92 close relatives/cohabitants. HTLV-1 infection was diagnosed by detection of antibodies and proviral DNA. The LTR region was sequenced and analyzed for genetic distances (VESPA software), in addition to determination and identification of polymorphisms to define HTLV-1 family signatures. Results Fifty seven of the 120 subjects enrolled had antibodies against HTLV-1 and were typified as HTLV-1 by PCR. The prevalence rate of HTLV-1 infection in family members of infected index cases was 31.52% (29/92). The infection was significantly associated with gender, age and prolonged lactation. Identity of LTR sequences and presence of polymorphisms revealed high prevalence of mother-to-child and interspousal transmission of HTLV-1 among these families. Conclusion There is an ongoing and silent transmission of HTLV-1 through vertical and sexual routes within family clusters in Northwest Argentina. This evidence highlights that HTLV-1 infection should be considered as a matter of public health in Argentina, in order to introduce preventive measures as prenatal screening and breastfeeding control.

Amostras de soro sanguineo (n: 110) de individuos de comportamento de risco e doadores de sangue da cidade de Cordoba, na Argentina, com perfis de reactividade para HIV-1 e HTLV-I/II indeterminada por Western blot (Wb), foram estudadas para anticorpos especificos contra HTLV-I/II e HIV-1 por meio do Ensaio de Imunofluorescencia Indireta (IFI). Este estudo foi realizado para caracterizar as reacoes putativas com proteinas HIV-1 e HTLV-I/II e resolver o estado da infeccao por retrovirus destes individuos. Os resultados mostram que os soros dos doadores sanguineos que apresentam padroes indeterminados para HTLV-I/II e HIV-1 no Wb nao sao reagentes contra HTLV-I/II e HIV-1 por IFI. Mas, um alto indice de amostras de individuos com alto risco com resultado indeterminado no Wb para HIV-1 e HTLV-I/II apresentaram resultados positivos para HTLV-I/II e HIV-1 por IFI, respectivamente. Nosso estudo sugere que a reatividade indeterminada para HTLV-HIV na populacao de baixo risco deve-se a uma reacao cruzada contra antigenos nao virais; e que na populacao de alto risco as amostras indeterminadas apresentam reacao cruzada entre as proteinas HIV-1 e HTLV-I/II no Wb. Estes resultados indicam que se faz preciso pesquisar a reatividade de HTLV-I/II nas amostras indeterminadas de HIV-1 e vice-versa, para confirmar o diagnostico. Por ultimo, este trabalho mostra a utilidade potencial da IFI para determinar o estado de infeccao HIV-1 e HTLV-I/II dos individuos com perfis indeterminados por Wb, permitindo assim, a resolucao do estado real de infeccao por retrovirus.

We compared the indirect immunofluorescence assay (IFA) with Western blot (Wb) as a confirmatory method to detect antibodies anti retrovirus (HIV-1 and HTLV-I/II). Positive and negative HIV-1 and HTLV-I/II serum samples from different risk populations were studied. Sensitivity, specificity, positive, negative predictive and kappa index values were assayed, to assess the IFA efficiency versus Wb. The following cell lines were used as a source of viral antigens: H9 ( HTLV-III b); MT-2 and MT-4 (persistently infected with HTLV-I) and MO-T (persistently infected with HTLV-II). Sensitivity and specificity rates for HIV-1 were 96.80% and 98.60% respectively, while predictive positive and negative values were 99.50% and 92.00% respectively. No differences were found in HIV IFA performance between the various populations studied. As for IFA HTLV system, the sensitivity and specificity values were 97.91% and 100% respectively with positive and negative predictive values of 100% and 97.92%. Moreover, the sensitivity of the IFA for HTLV-I/II proved to be higher when the samples were tested simultaneously against both antigens (HTLV-I-MT-2 and HTLV-II-MO-T). The overall IFA efficiency for HIV-1 and HTLV-I/II-MT-2 antibody detection probed to be very satisfactory with an excellent correlation with Wb (Kappa indexes 0.93 and 0.98 respectively). These results confirmed that the IFA is a sensitive and specific alternative method for the confirmatory diagnosis of HIV-1 and HTLV-I/II infection in populations at different levels of risk to acquire the infection and suggest that IFA could be included in the serologic diagnostic algorithm.

We carried out a seroepidemiologic survey to define the prevalence of human T cell lymphotropic virus types 1/2 (HTLV-1/2) infections among aboriginal populations from isolated regions of northern Argentina and the Amazon region of Peru. Antibodies against HTLV were measured with agglutination tests and confirmed with by an immunofluorescence assay (IFA) and Western blotting. Five (6.94%) of 72 samples from the Tobas Indians in Argentina were positive by the IFA; two samples were typed as HTLV-1 (2.78%), two as HTLV-2 (2.78%), and one (1.39%) could not be typed because it had similar antibody titers against both viruses. No positive samples were found among 84 Andinos Puneños and 47 Matacos Wichis Indians. Seroprevalences of 2.50% (1 of 40) and 1.43% (1 of 70) for HTLV-1 were observed among Wayku and San Francisco communities in the Amazon region of Peru, and seroprevalences of 4.54% (1 of 22) and 2.38% (1 of 42) for HTLV-2 were observed among Boca Colorada and Galilea communities. No serologic evidence of human immunodeficiency virus (HIV) infection was found among the Indians tested. These results indicated the presence of HTLV-1 and HTLV-2 in the indigenous populations of Argentina and Peru. Moreover, the lack of HIV infection indicates that the virus has probably not yet been introduced into these populations.