Epidemiological aspects of hepatitis C virus infection among renal transplant recipients in Central Brazil

An investigation was conducted involving 255 renal transplant recipients in the state of Goiás, Central Brazil, to determine the prevalence of hepatitis C virus (HCV), its risk factors, the genotypes involved, and the level of alanine aminotransferase (ALT) present in the patients. All serum samples were tested for anti-HCV antibodies and HCV RNA. Forty-one patients were anti-HCV and/or HCV RNA positive, resulting in an overall HCV infection prevalence of 16.1% (95% CI: 11.9-21.3). A multivariate analysis of risk factors showed that a history of blood transfusions without anti-HCV screening, the length of time spent on hemodialysis, and renal transplantation before 1994 are all associated with HCV positivity. In HCV-positive patients, only 12.2% had ALT levels above normal. Twenty-eight samples were genotyped as genotype 1, subtypes 1a (62.5%) and 1b (31.3%), and two samples (6.2%) were genotype 3, subtype 3a. These data show a high prevalence of HCV infection and low ALT levels in the studied population. The risk factor analysis findings emphasize the importance of public health strategies such as anti-HCV screening of candidate blood and organ donors, in addition to the stricter adoption of hemodialysis-specific infection control measures. The present study also demonstrates that HCV genotype 1 (subtype 1a) is predominant in this population.

Evidence for the co-circulation of dengue virus type 3 genotypes III and V in the Northern region of Brazil during the 2002-2004 epidemics

The reintroduction of dengue virus type 3 (DENV-3) in Brazil in 2000 and its subsequent spread throughout the country was associated with genotype III viruses, the only DENV-3 genotype isolated in Brazil prior to 2002. We report here the co-circulation of two different DENV-3 genotypes in patients living in the Northern region of Brazil during the 2002-2004 epidemics. Complete genomic sequences of viral RNA were determined from these epidemics, and viruses belonging to genotypes V (Southeast Asia/South Pacific) and III were identified. This recent co-circulation of different DENV-3 genotypes in South America may have implications for pathological and epidemiological dynamics.

Genetic variability in the 5' UTR and NS5A regions of hepatitis C virus RNA isolated from non-responding and responding patients with chronic HCV genotype 1 infection

Sequence variation among different hepatitis C virus (HCV) isolates has adaptive significance and reflects the modes and intensities of selection mechanisms operating on the virus. In this work, we sought to investigate using classical population genetics parameters, the genetic variability of HCV genotype 1 using the 5' UTR and NS5A regions from treatment non-responding and responding groups of patients. Both regions showed low genetic varia-bility and the 5' UTR showed neutral deviation. No differences were observed in the nonsynonymous/synonymous nucleotide substitution ratio among groups for NS5A. The analysis of molecular variance test of the 5' UTR region showed an 11.94% variation among groups. Phylogenetic analysis showed no correlation between sequence variations and therapeutic responses.

Characterization of polymorphisms in the mannose-binding lectin gene promoter among human immunodeficiency virus 1 infected subjects

The present study investigated the prevalence of mutations in the -550 (H/L) and -221 (X/Y) mannose-binding lectin (MBL) gene promoter regions and their impact on infection by human immunodeficiency virus 1 (HIV-1) in a population of 128 HIV-1 seropositive and 97 seronegative patients. The allele identification was performed through the sequence-specific primer polymerase chain reaction method, using primer sequences specific to each polymorphism. The evolution of the infection was evaluated through CD4+ T-lymphocyte counts and plasma viral load. The allele and haplotype frequencies among HIV-1-infected patients and seronegative healthy control patients did not show significant differences. CD4+ T-lymphocyte counts showed lower levels among seropositive patients carrying haplotypes LY, LX and HX, as compared to those carrying the HY haplotype. Mean plasma viral load was higher among seropositive patients with haplotypes LY, LX and HX than among those carrying the HY haplotype. When promoter and exon 1 mutations were matched, it was possible to identify a significantly higher viral load among HIV-1 infected individuals carrying haplotypes correlated to low serum levels of MBL. The current study shows that haplotypes related to medium and low MBL serum levels might directly influence the evolution of viral progression in patients. Therefore, it is suggested that the identification of haplotypes within the promoter region of the MBL gene among HIV-1 infected persons should be further evaluated as a prognostic tool for AIDS progression.

Molecular characterization of hepatitis A virus isolates from Goiânia, Goiás, Brazil

Hepatitis A virus (HAV) infection is a public health problem worldwide and the virus has been classified into six genotypes. In Brazil, the only genotype that has been found is genotype I, predominately from subgenotype IA. Here, the HAV genotypes were analyzed of 18 isolates circulating between 1996-2001 in Goiânia, state of Goiás, Brazil. Viral RNA was extracted from 18 serum samples and amplified (RT-PCR/nested-PCR), followed by the genomic sequencing of the VP1/2A junction region of the HAV genome. Sequences of 168 nucleotides were compared and analyzed using the BLAST N, Clustal X and PAUP v. 4.10b programs. All samples were classified as genotype I, with 10 belonging to subgenotype IA and eight to subgenotype IB. The subgenotype IA isolates showed greater diversity than the subgenotype IB isolates at the nucleotide level. Elevated identity values were found between isolates obtained in this study and those from other regions of the world, including Brazil, highlighting the high conservation among different isolates of this virus. However, changes in the HAV subgenotype circulation could also be observed during the evaluated period.

Infección por virus pandémico (H1N1) 2009 en Andalucía

In April 2009, in response to the WHO's alert due to the existence of human infection cases with a new AH1N1 influenza virus, known as swine flu, Andalusian Health Authorities trigger an specific action plan. The surveillance actions developped provided us with appropriate clinical, epidemiological and virological characteristics of the disease. During the first few days, contingency plans were set up based on epidemiological surveillance and outbreak control measures were adopted through early alert and rapid response systems. After phase 6 was declared, influenza sentinel and severe cases surveillance were used in order to plan healthcare services, to reduce transmission and to identify and protect the most vulnerable population groups. Behaviour of pandemic influenza in Andalusia was similar to that observed in the rest of the world. Atack rate was similar to a seasonal flu and the peak was reached at the 46th/2009 week. Most of them were mild cases and affected particularly to young people. The average age of hospitalised patients was 32. Prior pulmonary disease, smoking and morbid obesity (BMI>40) were the most common pathologies and risk factors in severe cases. An impact scenario of pandemic wave in Andalusia, with an expected attack rate from 2 to 5%, was prepared considering watt observed in the southern hemisphere. Characteristics of the epidemic concerning its extent, severity and mortality rate were adjusted to this scenario.

Prevención del Cáncer de cuello de útero: El cáncer de cuello de útero es provocado por el Virus del Papiloma Humano

Cartel y Folleto: Prevención del Cáncer de cuello de útero: El cáncer de cuello de útero es provocado por el Virus del Papiloma Humano. Díptico de citas: Prevención del Cáncer de cuello de útero. Citas para la vacunación frente al papilomavirus

Duplex-PCR assay for the detection of adenovirus and respiratory syncytial virus in nasopharyngeal samples

Human adenovirus (HAdV) and human respiratory syncytial virus (HRSV) are important etiologic agents of acute respiratory infections. In this study, a duplex polymerase chain reaction (PCR) assay was developed for the simultaneous detection of HAdV and HRSV in clinical samples. Sixty previously screened nasopharyngeal aspirates were used: 20 HAdV-positive, 20 HRSV-positive and 20 double-negative controls. Eight samples were positive for both viruses. The duplex PCR assay proved to be as sensitive and specific as single-target assays and also detected the mixed infections with certainty. The identification of both viruses in a single reaction offers a reduction in both cost and laboratory diagnostic time.

Acute retinal necrosis in primary herpes simplex virus type I infection.

Here we report the case of an immunocompetent 8-year-old child who developed acute retinal necrosis concomitant with a primary herpes simplex virus type I infection. Ocular inflammation changed along with the development of a specific antibody titer in the serum. This evidence suggests that the immune response of the host can significantly modulate the clinical aspect of the ocular infection.

Dengue virus type 3 in Brazil: a phylogenetic perspective

Circulation of a new dengue virus (DENV)-3 genotype was recently described in Brazil and Colombia, but the precise classification of this genotype has been controversial. Here we perform phylogenetic and nucleotide-distance analyses of the envelope gene, which support the subdivision of DENV-3 strains into five distinct genotypes (GI to GV) and confirm the classification of the new South American genotype as GV. The extremely low genetic distances between Brazilian GV strains and the prototype Philippines/L11423 GV strain isolated in 1956 raise important questions regarding the origin of GV in South America.

Comparative study of two extraction methods for enteric virus recovery from sewage sludge by molecular methods

The aim of this study was to compare two nucleic acid extraction methods for the recovery of enteric viruses from activated sludge. Test samples were inoculated with human adenovirus (AdV), hepatitis A virus (HAV), poliovirus (PV) and rotavirus (RV) and were then processed by an adsorption-elution-precipitation method. Two extraction methods were used: an organic solvent-based method and a silica method. The organic-based method was able to recoup 20% of the AdV, 90% of the RV and 100% of both the PV and HAV from seeded samples. The silica method was able to recoup 1.8% of the AdV and 90% of the RV. These results indicate that the organic-based method is more suitable for detecting viruses in sewage sludge.

Retrovirus-host interactions. The mouse mammary tumor virus model.

Mouse mammary tumor virus (MMTV) is a retrovirus which can induce mammary carcinomas in mice late in life by activation of proto-oncogenes after integration in their vicinity. Surprisingly, it requires a functional immune system to achieve efficient infection of the mammary gland. This requirement became clear when it was discovered that it has developed strategies to exploit the immune response. Instead of escaping immune detection, it induces a vigorous polyclonal T-B interaction which is required to induce a chronic infection. This is achieved by activating and then infecting antigen presenting cells (B cells), expressing a superantigen on their cell surface and triggering unlimited help by the large number of superantigen-specific T cells. The end result of this strong T-B interaction is the proliferation and differentiation of the infected B cells leading to their long term survival.

Circulating natural killer and γδ T cells decrease soon after infection of rhesus macaques with lymphocytic choriomeningitis virus

Rhesus macaques infected with the WE strain of lymphocytic choriomeningitis virus (LCMV-WE) serve as a model for human infection with Lassa fever virus. To identify the earliest events of acute infection, rhesus macaques were monitored immediately after lethal infection for changes in peripheral blood mononuclear cells (PBMCs). Changes in CD3, CD4, CD8 and CD20 subsets did not vary outside the normal fluctuations of these blood cell populations; however, natural killer (NK) and γδ T cells increased slightly on day 1 and then decreased significantly after two days. The NK subsets responsible for the decrease were primarily CD3-CD8+ or CD3-CD16+ and not the NKT (primarily CD3+CD56+) subset. Macaques infected with a non-virulent arenavirus, LCMV-Armstrong, showed a similar drop in circulating NK and γδ T cells, indicating that this is not a pathogenic event. V³9 T cells, representing the majority of circulating γδ T cells in rhesus macaques, displayed significant apoptosis when incubated with LCMV in cell culture; however, the low amount of cell death for virus-co-cultured NK cells was insufficient to account for the observed disappearance of this subset. Our observations in primates are similar to those seen in LCMV-infected mice, where decreased circulating NK cells were attributed to margination and cell death. Thus, the disappearance of these cells during acute hemorrhagic fever in rhesus macaques may be a cytokine-induced lymphopenia common to many virus infections.

Seasonal dynamics of Aedes aegypti (Diptera: Culicidae) in the northernmost state of Brazil: a likely port-of-entry for dengue virus 4

Roraima is the northernmost state of Brazil, bordering both Venezuela and Guyana. Appropriate climate and vector conditions for dengue transmission together with its proximity to countries where all four dengue serotypes circulate make this state, particularly the capital Boa Vista, strategically important for dengue surveillance in Brazil. Nonetheless, few studies have addressed the population dynamics of Aedes aegypti in Boa Vista. In this study, we report temporal and spatial variations in Ae. aegypti population density using ovitraps in two highly populated neighbourhoods; Centro and Tancredo Neves. In three out of six surveys, Ae. aegypti was present in more than 80% of the sites visited. High presence levels of this mosquito suggest ubiquitous human exposure to the vector, at least during part of the year. The highest infestation rates occurred during the peak of the rainy seasons, but a large presence was also observed during the early dry season (although with more variation among years). Spatial distribution of positive houses changed from a sparse and local pattern to a very dense pattern during the dry-wet season transition. These results suggest that the risk of dengue transmission and the potential for the new serotype invasions are high for most of the year.

Failure to demonstrate experimental vertical transmission of the epidemic strain of Chikungunya virus in Aedes albopictus from La Réunion Island, Indian Ocean

Aedes albopictus was responsible for transmission in the first outbreak of chikungunya (CHIK) on La Réunion Island, Indian Ocean, in 2005-2006. The magnitude of the outbreak on this island, which had been free of arboviral diseases for over 30 years, as well as the efficiency of Ae. albopictus as the main vector, raises questions about the maintenance of the CHIK virus (CHIKV) through vertical transmission mechanisms. Few specimens collected from the field as larvae were found to be infected. In this study, Ae. albopictus originating from La Réunion were orally infected with a blood-meal containing 10(8) pfu/mL of the CHIKV epidemic strain (CHIKV 06.21). Eggs from the first and second gonotrophic cycles were collected and raised to the adult stage. The infectious status of the progeny was checked (i) by immunofluorescence on head squashes of individual mosquitoes to detect the presence of viral particles or (ii) by quantitative RT-PCR on mosquito pools to detect viral RNA. We analysed a total of 1,675 specimens from the first gonotrophic cycle and 1,709 from the second gonotrophic cycle without detecting any viral particles or viral RNA. These laboratory results are compared to field records.