Detection and molecular characterization of sporadic cases of acute human hepatitis E virus infection in Uruguay.

In developing countries, hepatitis E virus (HEV) infection is a public-health concern because it causes epidemics and waterborne outbreaks. In South America, few HEV strains have been characterized at the molecular level. We report the detection and molecular analysis of the first set of sporadic cases of autochthonous human genotype 3 HEV infection in Uruguay.

Identification of a new HIV Type 1 circulating recombinant form (CRF38_BF1) in Uruguay.

Recombination has been shown to be an important force in HIV-1 evolution. Recombination contributes to an increase in genetic variation and hinders vaccine design efforts. Several molecular epidemiology studies in South America described the circulation of subtypes B, F, and C as well as several B/F1 recombinants. This study performed by nucleotide sequencing in at least two genes of 89 samples from Uruguay has shown a complex HIV-1 epidemic characterized by the cocirculation of subtype B, and subtype C strains, together with an important group of BF1 recombinant viruses, including isolates similar to CRF12_BF. In addition we identified a new circulating recombinant form, designated CRF38_BF(1), which was dominant in the recombinant virus group.

Juquitiba-like hantavirus from 2 nonrelated rodent species, Uruguay.

Serologic and genetic analyses indicate that a Juquitiba-like hantavirus circulates in Maldonado, Uruguay. This virus is carried by 2 rodent species, Oligoryzomys nigripes and Oxymycterus nasutus. The same hantavirus in 2 nonrelated species can be explained by a spillover infection or a host-switching event.

Genetic characterization of respiratory syncytial viruses isolated from consecutive acute respiratory infections in a HIV infected child.

BACKGROUND: Human respiratory syncytial virus (HRSV) was isolated from a 2-year-old child suffering from perinatally transmitted AIDS in the course of three distinct episodes of respiratory infections. The first episode occurred in the winter of 1994, the following two episodes of cough and fever occurred two and 4 months after the initial episode. OBJECTIVE: To analyze the genetic variability of the child's HRSV strains, and with contemporary circulating HRSV isolates. RESULTS: The three child's HRSV isolates belonged to group B. Sequence analysis of the attachment (G) protein gene (which has the highest degree of antigenic and genetic diversity in HRSV), demonstrated no difference in the sequence obtained from the three isolates recovered from the child. Comparison of the child's HRSV strain with contemporary circulating group B HRSV isolates showed a close sequence similarity with one of them. CONCLUSIONS: The immunodeficiency in an HIV-positive child may have resulted in the recurrent isolation of one HRSV strain. Although it cannot be discarded the possibility that the recurrent episodes might be re-infections, it is unlikely in view of the lack of change in the HRSV glycoprotein G. This is the first study that analyzes the genetic variation in HRSV isolates from consecutive respiratory disease episodes in an immunosuppressed patient.

Prevalences, genotypes, and risk factors for HIV transmission in South America.

HIV cross-sectional studies were conducted among high-risk populations in 9 countries of South America. Enzyme-linked immunosorbent assay screening and Western blot confirmatory testing were performed, and env heteroduplex mobility assay genotyping and DNA sequencing were performed on a subset of HIV-positive subjects. HIV prevalences were highest among men who have sex with men (MSM; 2.0%-27.8%) and were found to be associated with multiple partners, noninjection drug use (non-IDU), and sexually transmitted infections (STIs). By comparison, much lower prevalences were noted among female commercial sex workers (FCSWs; 0%-6.3%) and were associated mainly with a prior IDU and STI history. Env subtype B predominated among MSM throughout the region (more than 90% of strains), whereas env subtype F predominated among FCSWs in Argentina and male commercial sex workers in Uruguay (more than 50% of strains). A renewed effort in controlling STIs, especially among MSM groups, could significantly lessen the impact of the HIV epidemic in South America.

Seroincidence and phylogeny of human immunodeficiency virus infections in a cohort of commercial sex workers in Montevideo, Uruguay.

A cohort study involving 60 human immunodeficiency virus (HIV)-negative male transvestite commercial sex workers (CSWs) was conducted in Montevideo, Uruguay in 1999-2001. Serum samples were tested for HIV by an enzyme-linked immunosorbent assay screening with immunoblot confirmation. Six participants seroconverted for an incidence-density rate of 6.03 (95% confidence interval = 2.21-13.12) per 100 person-years. Inconsistent condom use during client sex (adjusted hazard ratio [AHR] = 6.7), during oral sex (AHR = 5.6), and at the last sexual encounter (AHR = 7.8), and use of marihuana (AHR = 5.4) were marginally associated with HIV seroconversion. Five samples were genotyped in the protease and reverse transcriptase regions; three were subtypes B and two were BF recombinants. Full genome analysis of four samples confirmed all three subtype B samples and one of the two BF recombinants. Male transvestite CSWs sustained a high rate of HIV infection. Larger prospective studies are required to better define subtypes and associated sexual and drug-related risk factors.

Evaluation of a new NASBA assay for the qualitative detection of hepatitis C virus based on the NucliSens Basic Kit reagents.

BACKGROUND: Direct detection of HCV RNA by nucleic acid amplification methods is an essential tool in the diagnosis of HCV infections. In-house developed methods based on reverse transcribed polymerase chain reaction (RT-PCR) are widely used but they are laborious and usually lack the standardization required by clinical laboratories. OBJECTIVES: To evaluate the sensitivity and the clinical performance of an HCV specific nucleic acid sequence based amplification (NASBA) assay based on the commercially available, NucliSens Basic Kit (bioMérieux) reagents. STUDY DESIGN: The analytical sensitivity of the Basic Kit-based HCV assay (BK-HCV) was determined using dilutions of the First World Health Organization International Standard for HCV RNA. The performance of the BK-HCV was evaluated at two study sites in comparison with in-house RT-nested PCR (RT-nPCR) by testing a total of 77 plasma specimens. Additional HCV laboratory tests such as Amplicor HCV v2.0 (Roche Diagnostics) and genotype were also included in the comparative analysis. RESULTS: The sensitivity of the BK-HCV was 100-150 IU/ml HCV RNA (85-100% hit rate). When evaluating the clinical performance, we found 96-100% correlation between BK-HCV and RT-nPCR, and 85-91% correlation between BK-HCV and Amplicor. The level of efficiency of the BK-HCV for detecting prevalent HCV genotypes was equal to in house RT-nPCR and Amplicor. CONCLUSIONS: The BK-HCV offers adequate sensitivity for diagnostic purposes and equivalent clinical performance to in-house RT-nPCR assays. The BK-HCV could become a suitable alternative to the in-house amplification methods, providing standardized reagents and procedures, plus rapid results to clinical laboratories.

Sexual transmission of hepatitis B virus, hepatitis C virus, and human immunodeficiency virus type 1 infections among male transvestite comercial sex workers in Montevideo, Uruguay.

Prostitution may constitute a risk behavior for infection with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). We conducted a seroepidemiologic study among 200 male transvestite commercial sex workers (CSWs) in Montevideo, Uruguay in 1999. Evidence of exposure to HBV, HCV, and HIV was found in 101 (50.5%), 13 (6.5%), and 43 (21.5%) individuals, respectively. Positivity for HIV was correlated with both HBV (odds ratio [OR] = 2.15, 95% confidence interval [CI] = 1.01-4.67) and HCV (OR = 3.47, 95% CI = 0.90-12.79) infection. Predictors of infection were older age (> or = 26 years; P < 0.01) for all 3 viruses and time in CSW (> or = 5 years; P < 0.05) for HBV and HIV. Prior history of use of drugs (OR = 3.54, 95% CI = 1.09-11.52) and sexual contact with foreigners (OR = 9.2, 95% CI = 1.16-73.12) were found to be associated only with HCV infection. Sexual transmission of these viruses constitutes a significant problem among male transvestite CSWs.

Molecular Epidemiology of HIV Type 1 in Ecuador, Peru, Bolivia, Uruguay, and Argentina.

Surveillance for HIV infection among people at increased risk was conducted in five countries in South America. Seroprevalence studies were conducted in more than 36,000 people in Ecuador, Peru, Boliva, Uruguay, and Argentina, along with genetic analysis of the HIV-1 strains. In all countries, the prevalence of HIV-1 among men who have sex with men (MSM) was high (3-30%), whereas the prevalence among female commercial sex workers (FCSMs) was low (0.3-6%). By envelope heteroduplex mobility assay, subtype B predominated in MSM communities and in FCSWs in Ecuador, Bolivia, and Peru. A new genetic screening assay, the multiregion hybridization assay for subtypes B and F (MHA-bf), was developed to improve large-scale genetic screening in South America. MHA-bf can screen four regions of the genome for subtype B or subtype F, and thus can detect most recombinants. The sensitivity of MHA-bf when applied to a panel of pure subtypes and CRF12_BF was 100%, and 88% of unique recombinants were also detected as recombinant. Using MHA-bf, more than 80% of samples from Ecuador, Peru, and Bolivia were classified as pure subtype B, whereas in Uruguay and Argentina this proportion was only 30 to 40%. BF recombinants were the most prevalent form of HIV-1 in Uruguay and Argentina. Subtype B is the most common subtype in countries lacking injecting drug use (IDU) epidemics, whereas BF recombinants are more common in countries where extensive IDU epidemics have been documented, suggesting the ontogeny of recombinant strains in particular risk groups in South America.

Variantes antigénicas del virus respiratorio sincicial en Argentina y Uruguay / Antigenic variants of the respiratory syncytial virus in Argentina and Uruguay

Se realizó la caracterización de variantes antigénicas del virus respiratório sincicial (VRS) en 160 aspirados nasofaringeos de niños menores de 5 años de Argentina y Uruguay con infección respiratoria aguda con diagnóstico etiológico positivo para VRS. Los resultados para Argentina demostraron que el 20,9% de las muestras partenció al subtipo A, el 76,9% al subtipo B y el 2,2% a otros subtipos aún no caracterizados. Para Uruguay el 5,5% perteneció al grupo A, el 81% al grupo B y el 13,5% a otras variantes. En ambos paises predominó la variante antigénica B. La correlación de estas variantes antigénicas del VRS con el cuadro clínico y epidemiológico está actualmente en estudio

Variantes antigénicas del virus respiratorio sincicial en Argentina y Uruguay / Antigenic variants of the respiratory syncytial virus in Argentina and Uruguay

Se realizó la caracterización de variantes antigénicas del virus respiratório sincicial (VRS) en 160 aspirados nasofaringeos de niños menores de 5 años de Argentina y Uruguay con infección respiratoria aguda con diagnóstico etiológico positivo para VRS. Los resultados para Argentina demostraron que el 20,9% de las muestras partenció al subtipo A, el 76,9% al subtipo B y el 2,2% a otros subtipos aún no caracterizados. Para Uruguay el 5,5% perteneció al grupo A, el 81% al grupo B y el 13,5% a otras variantes. En ambos paises predominó la variante antigénica B. La correlación de estas variantes antigénicas del VRS con el cuadro clínico y epidemiológico está actualmente en estudio (AU)