Health care importance of Treponema pallidum, Chagas' disease and Human immunodeficiency virus 1 among Amerindians of Argentina: an observational study / Importancia en el sistema de salud de la infección por Treponema pallidum, la enfermedad de Chagas y el virus de la inmunodeficiencia humana 1 en amerindios de Argentina: un estudio observacional

The objective of this study was to estimate the prevalence of Treponema pallidum, Trypanosoma cruzi and Human immunodeficiency virus 1 (HIV-1) in five Amerindian populations of Argentina. A retrospective study was conducted among 857 Amerindian populations (112 Kollas, 298 Mbyá-guaraníes, 79 Sagua Huarpes, 368 Wichis) from 2007 to 2010. Screening and confirmation of T. pallidum, T. cruzi and HIV-1 were performed. T. pallidum and T. cruzi infections were detected in all communities with an overall prevalence rate of 4.2% and 16.8%, respectively. Although HIV was not detected, syphilis and Chagas' disease represent a challenge for the health care system and the reinforcement of public health strategies is necessary considering the socioeconomic isolation of these populations.

El objetivo de este trabajo fue estimar la prevalencia de Treponema pallidum, Trypanosoma cruzi y virus de la inmunodeficiencia humana (HIV-1) en 5 comunidades originarias de Argentina. Para ello, se realizó un estudio retrospectivo en 857 individuos (112 kollas, 298 mbyá-guaraníes, 79 sagua huarpes, 368 wichis) desde el 2007 hasta el 2010. Se realizó el diagnóstico completo para T. pallidum, T. cruzi y HIV-1. En todas las comunidades se confirmaron infecciones por T. pallidum y T. cruzi con una prevalencia total del 4,2 y del 16,8%, respectivamente. Aunque no se detectó HIV-1, sífilis y Chagas, representan un desafío para el sistema de salud, teniendo que reforzarse las estrategias de salud pública teniendo en cuenta el aislamiento socio-económico que sufren estas poblaciones.

Health care importance of Treponema pallidum, Chagas' disease and Human immunodeficiency virus 1 among Amerindians of Argentina: an observational study.

The objective of this study was to estimate the prevalence of Treponema pallidum, Trypanosoma cruzi and Human immunodeficiency virus 1 (HIV-1) in five Amerindian populations of Argentina. A retrospective study was conducted among 857 Amerindian populations (112 Kollas, 298 Mbyá-guaraníes, 79 Sagua Huarpes, 368 Wichis) from 2007 to 2010. Screening and confirmation of T. pallidum, T. cruzi and HIV-1 were performed. T. pallidum and T. cruzi infections were detected in all communities with an overall prevalence rate of 4.2% and 16.8%, respectively. Although HIV was not detected, syphilis and Chagas' disease represent a challenge for the health care system and the reinforcement of public health strategies is necessary considering the socioeconomic isolation of these populations.

HDAg-L variants in covert hepatitis D and HBV occult infection among Amerindians of Argentina: new insights.

BACKGROUND: Guidelines suggest that all HBsAg-positive patients should be tested for anti-HDV IgG antibodies and to confirm active hepatitis D virus (HDV) infection by detection of HDV RNA by reverse transcriptase (RT) polymerase chain reaction (PCR). OBJECTIVES: The aim of this study was to determine the serological prevalence and molecular features of HDV within an Amerindian community from Argentina exhibiting positivity for HBsAg and/or anti-HBc total Ig. STUDY DESIGN: Forty-six plasma samples were tested for the detection of total anti-HDV antibodies by ELISA. Concomitantly, a partial RNA region coding for the delta antigen (HDAg) was amplified by RT-nested PCR (RT-nPCR). In silica translation of DNA sequences into the amino acid (aa) sequence of HDAg-S (aa110-195) and HDAg-L (aa110-214) was performed. RESULTS: Out of 46 HDV non-reactive samples by ELISA, 3 were HDV RNA positive by RT-nPCR. These samples were anti-HBc-only positive, 2 of them identified as cases of occult hepatitis B infection (OBI). The 3 cases were HBeAg-negative and showed normal ALT/AST levels. All sequences were ascribed to HDV genotype 1, but exhibited nucleotide differences in HDAg-L coding region, among which, mutations at codons 197 and 201 - reportedly known to promote in vitro an unsuitable interaction with HBsAg - were observed. CONCLUSIONS: These results provide evidence of covert HDV infection even among OBI, highlighting the need to reevaluate the currently applied guidelines for HDV diagnostic algorithms, as well as to explore if the observed mutations promote any effect on HDV pathogenesis.

New natural variants of hepatitis B virus among Amerindians from Argentina with mainly occult infections.

BACKGROUND: Hepatitis B virus infection is frequent among Amerindians. In Argentina HBV genotypes A, B, C, D, E, F and H were described in different populations, while some cases of occult hepatitis B infection (OBI) were reported in human immunodeficiency virus (HIV) coinfected patients. OBJECTIVE: To determine the prevalence, genetic diversity of HBV and to analyze the deduced amino acid sequence of both S and viral polymerase (P) genes among Amerindians of Argentina. STUDY DESIGN: A cross-sectional study including 561 individuals belonging to distinct ethnic groups, the Mbyá-guaraní (MG), the Kolla (K), the Sagua-Huarpe (SH) and the Wichi (W) was performed. RESULTS: The prevalence of HBsAg was 1.7% and 1.4% for the MG and SH, respectively, while anti-HBc was detected in all communities. HBV DNA of S/P and preCore-Core genomic regions were amplified by nested polymerase chain reaction in 59 reactive samples for anti-HBc total Ig and/or HBsAg. Of them, thirteen exhibited detectable HBV DNA, eleven of which were identified as OBI. Genotype F was predominant in the MG community with co-circulation of subgenotypes F4, F1b, A2 and D3, while subgenotype C2 prevailed within the SH community. All cases exhibited the polymorphism rtL217R within the RT domain associated to resistance to adefovir. Mutations rtD206E and rtV207I associated with lamivudine resistance were found in two MG and three SH respectively. Other new substitutions were described within the P sequence. CONCLUSIONS: This study shows for the first time the predominance of OBI, HBV subgenotypes and natural variants in Amerindians from Argentina.

Predominance of human lymphotropic T cell virus type 2 subtype B in urban populations of Argentina.

Human T-lymphotropic virus subtype b (HTLV-2b) infection has been described among aborigines from Northern Argentina, while HTLV-2a has been described in an injecting drug user (IDU) from a Central region, similar to the situation in Spain, the United States, and Brazil. In this study, 22 of the 26 strains analyzed from blood donors and HIV-1(+) individuals were HTLV-2b (84.6%) clustering with Amerindian references, while 4 HIV-1(+) (15.4%) were HTLV-2a. HTLV-2a sequences were closely related to Brazilian references in contrast to the previous Argentinean IDU strain that clustered with Africans and Amerindians from North America. In summary, these findings show that HTLV-2b is the major strain circulating in an urban population of Argentina. HTLV-2a/b could have been introduced from endemic South American countries such as Brazil and because of contact with other populations such as IDUs from Europe despite its introduction due to the increasing internal migration of aborigines to large urban centers. Considering this results and recent data about the dissemination of HTLV-1 in residents of Buenos Aires city, new studies among non-at-risk groups for HTLV-1/2 infection should be performed.

[Seroprevalence of HTLV-1/2 in blood donors from Misiones Province]. / Seroprevalencia de HTLV-1/2 en donantes de sangre de la Provincia de Misiones.

Human T-cell Lymphotropic viruses type 1 (HTLV-1), the first human oncoretrovirus to be discovered, is the etiologic agent of Adult T-cell Leukemia (ATL) and HTLV-1 Associated Mielopathy or Tropical Spastic Paraparesis (HAM/TSP). It is endemic worldwide, including the North of Argentina where both associated diseases have also been detected. No etiologic role has been described for HTLV-2, although it has been associated with HAM/TSP-like neurologic syndromes. Both retroviruses are endemic in native populations of The Americas, Africa and at-risk populations. They are transmitted through sex contact, parenterally and from mother to child. The aim of this study was to estimate the seroprevalence of HTLV-1/2 in a blood donor population from Misiones province. A total of 6912 accepted blood donations in 2008 were analyzed. HTLV-1/2 screening was performed with ELISA and particle agglutination, and reactive samples were confirmed by Western Blot. From the total, 5 samples resulted seropositive with a final prevalence of 0.00072. Out of the 5 positive samples, one was an HTLV, three HTLV-1 and one HTLV-2. These blood donors were residents of Posadas, Eldorado and Oberá, with no risk antecedents. This study demonstrates the presence of HTLV-1/2 in a population of Misiones with a prevalence rate similar to those reported among blood donors from non-endemic areas.

Seroprevalencia de HTLV-1/2 en donantes de sangre de la Provincia de Misiones / Seroprevalence of HTLV-1/2 in blood donors from Misiones Province

El Virus Linfotrópico T Humano tipo 1 (HTLV-1), primer oncorretrovirus humano descubierto, es el causante etiológico de la leucemia de células T del adulto (ATL) y de la mielopatía asociada al HTLV-1 o paraparesia espástica tropical (HAM/TSP). Es endémico en distintas partes del mundo, inclusive en el noroeste argentino, donde ambas enfermedades fueron detectadas. El HTLV-2, no tiene un rol etiológico definido, si bien ha sido asociado con síndromes neurológicos similares a la HAM/TSP. Ambos virus son endémicos en comunidades originarias del continente americano, tribus de Africa y poblaciones en riesgo. Ambos retrovirus se transmiten por vía sexual, parenteral y de madre a hijo. El objetivo de este trabajo fue determinar la seroprevalencia de HTLV-1/2 en una población de donantes de sangre de la provincia de Misiones. Se analizaron 6912 donaciones de sangre recibidas en el Banco de Sangre Central de la Provincia de Misiones durante 2008. La detección de anticuerpos se realizó por ELISA y aglutinación de partículas, y las muestras reactivas fueron confirmadas por Western Blot. Del total de muestras, 5 resultaron seropositivas con una prevalencia final de 0.00072. De ellas, una era HTLV, tres HTLV-1 y una HTLV-2 positiva. Los donantes positivos provenían de Posadas, Eldorado y Oberá, sin antecedentes de riesgo. Este estudio demuestra la presencia de HTLV-1/2 en donantes de sangre de Misiones, con cifras similares a las notificadas en donantes de sangre de zonas no endémicas.

Human T-cell Lymphotropic viruses type 1 (HTLV-1), the first human oncoretrovirus to be discovered, is the etiologic agent of Adult T-cell Leukemia (ATL) and HTLV-1 Associated Mielopathy or Tropical Spastic Paraparesis (HAM/TSP). It is endemic worldwide, including the North of Argentina where both associated diseases have also been detected. No etiologic role has been described for HTLV-2, although it has been associated with HAM/TSP-like neurologic syndromes. Both retroviruses are endemic in native populations of The Americas, Africa and at-risk populations. They are transmitted through sex contact, parenterally and from mother to child. The aim of this study was to estimate the seroprevalence of HTLV-1/2 in a blood donor population from Misiones province. A total of 6912 accepted blood donations in 2008 were analyzed. HTLV-1/2 screening was performed with ELISA and particle agglutination, and reactive samples were confirmed by Western Blot. From the total, 5 samples resulted seropositive with a final prevalence of 0.00072. Out of the 5 positive samples, one was an HTLV, three HTLV-1 and one HTLV-2. These blood donors were residents of Posadas, Eldorado and Oberá, with no risk antecedents. This study demonstrates the presence of HTLV-1/2 in a population of Misiones with a prevalence rate similar to those reported among blood donors from non-endemic areas.