Prevalence of Epstein-Barr virus antibodies in healthy children and adolescents in Vitória, State of Espírito Santo, Brazil

The prevalence and age distribution of Epstein-Barr virus infection varies in different populations and there is little information about the epidemiology of this infection in Brazil. We studied the prevalence of EBV antibodies in a sample of 283 children and adolescents between 1 and 21 years old. The sample was taken from two neighborhoods in Vitória (capital city of Espirito Santo, Brazil). The São Pedro (SP) neighborhood represented an area with lower socioeconomic status and the Praias (P) neighborhood represented an area with higher SES. Anti-VCA (Virus Capsid Antigen) antibodies were detected by ELISA and anti-EBNA (Epstein-Barr Nuclear Antigen) antibodies were detected by an anti-complement immunofluorescence method, both using commercial kits. The results showed an overall prevalence rates of anti-VCA and anti-EBNA of 71% and 54% respectively. The prevalence for both anti-EBV antibodies was higher and probably the infection occurred earlier in the SP neighborhood. Among the various socioeconomic factors studied only low family income and maternal education level were significantly correlated with a higher frequency of positive serology for anti-VCA. These results demonstrate that there is a high prevalence of EBV antibodies in children and adolescents living in Vitória, that occurs more frequently at a younger age in children from families with low socioeconomic status. In addition, the results demonstrate an intermediate age distribution pattern between those reported in developed and underdeveloped countries.

Spatio-temporal patterns of tuberculosis incidence in Ribeirão Preto, State of São Paulo, southeast Brazil, and their relationship with social vulnerability: a Bayesian analysis

INTRODUCTION: The purpose of this ecological study was to evaluate the urban spatial and temporal distribution of tuberculosis (TB) in Ribeirão Preto, State of São Paulo, southeast Brazil, between 2006 and 2009 and to evaluate its relationship with factors of social vulnerability such as income and education level. METHODS: We evaluated data from TBWeb, an electronic notification system for TB cases. Measures of social vulnerability were obtained from the SEADE Foundation, and information about the number of inhabitants, education and income of the households were obtained from Brazilian Institute of Geography and Statistics. Statistical analyses were conducted by a Bayesian regression model assuming a Poisson distribution for the observed new cases of TB in each area. A conditional autoregressive structure was used for the spatial covariance structure. RESULTS: The Bayesian model confirmed the spatial heterogeneity of TB distribution in Ribeirão Preto, identifying areas with elevated risk and the effects of social vulnerability on the disease. We demonstrated that the rate of TB was correlated with the measures of income, education and social vulnerability. However, we observed areas with low vulnerability and high education and income, but with high estimated TB rates. CONCLUSIONS: The study identified areas with different risks for TB, given that the public health system deals with the characteristics of each region individually and prioritizes those that present a higher propensity to risk of TB. Complex relationships may exist between TB incidence and a wide range of environmental and intrinsic factors, which need to be studied in future research.

Do differences exist between chronic hepatitis C genotypes 2 and 3?

Introduction Six genotypes of the hepatitis C virus (HCV) have been identified thus far, and their distribution is well defined. Genotype 1, which is the most prevalent worldwide, is always compared to genotypes 2 and 3, particularly in terms of treatment response. However, little is known about the differences between genotypes 2 and 3 because these genotypes are analyzed together in most studies. Therefore, the aim of this study was to evaluate differences in the clinical, epidemiological, laboratory, and histological parameters between HCV-2 and HCV-3. Methods Patients with chronic hepatitis C infected with genotypes 2 and 3 were studied retrospectively and compared according to clinical, laboratory, and histological aspects. Hepatitis C virus-ribonucleic acid (HCV-RNA) was analyzed quantitatively by TaqMan® real-time PCR, and the HCV genotype was determined by sequencing the 5′-untranslated region. Results A total of 306 patients with chronic HCV-2 (n=50) and HCV-3 (n = 256) were studied. Subtype 2b (n=17/50) and subtype 3a (n=244/256) were the most prevalent among patients infected with HCV-2 and HCV-3, respectively. The mean age was 47 ± 10 years, and there was a predominance of men in the group studied (61%). Comparative analysis between HCV-2 and HCV-3 showed a younger age (p=0.002), less prevalence of arterial hypertension (p=0.03), higher serum albumin levels (p=0.01), more advanced stage of liver fibrosis (p=0.03), and higher frequency of steatosis in patients with HCV-3 (p=0.001). After multivariate regression analysis, all the variables, except serum albumin, remained as variables associated with HCV-3 in the final model. Conclusions Clinical and histological differences exist between HCV-2 and HVC-3, which suggests the need for separate analyses of these genotypes.

Chlamydia trachomatis serotype A infections in the Amazon region of Brazil: prevalence, entry and dissemination

INTRODUCTION: Chlamydia infection is associated with debilitating human diseases including trachoma, pneumonia, coronary heart disease and urogenital diseases. Serotypes of C. trachomatis show a fair correlation with the group of diseases they cause, and their distribution follows a well-described geographic pattern. Serotype A, a trachoma-associated strain, is known for its limited dissemination in the Middle East and Northern Africa. However, knowledge on the spread of bacteria from the genus Chlamydia as well as the distribution of serotypes in Brazil is quite limited. METHODS: Blood samples of 1,710 individuals from ten human population groups in the Amazon region of Brazil were examined for antibodies to Chlamydia using indirect immunofluorescence and microimmunofluorescence assays. RESULTS: The prevalence of antibodies to Chlamydia ranged from 23.9% (Wayana-Apalai) to 90.7% (Awa-Guaja) with a mean prevalence of 50.2%. Seroreactivity was detected to C. pneumoniae and to all serotypes of C. trachomatis tested; furthermore, we report clear evidence of the as-yet-undescribed occurrence of serotype A of C. trachomatis. CONCLUSIONS: Specific seroreactivity not only accounts for the large extent of dissemination of C. trachomatis in the Amazon region of Brazil but also shows an expanded area of occurrence of serotype A outside the epidemiological settings previously described. Furthermore, these data suggest possible routes of Chlamydia introduction into the Amazon region from the massive human migration that occurred during the 1,700s.

Two decades of tuberculosis in a city in Northeastern Brazil: advances and challenges in time and space

Abstract: INTRODUCTION This study presents two decades of epidemiological data on tuberculosis (TB), in order to understanding the disease profile and its spatiotemporal dynamics. METHODS This descriptive study was performed in the City of Olinda/Pernambuco, Brazil, from 1991-2010, and it analyzed new patients with TB living in the city. We used the χ²-test with a p-value <0.05 to identify differences in trends. Incidence and cluster distribution were identified using spatial scan statistics. RESULTS In total, 6202 new cases were recorded during the two decades. The highest incidence occurred in 1995 (110 cases/100,000 inhabitants), and the lowest occurred in 2009 (65 cases/100,000 inhabitants) (β=-1.44; R²=0.43; p=0.0018). The highest mortality occurred in 1998 (16 deaths/100,000 inhabitants), and the lowest occurred in 2008 (5 deaths/100,000 inhabitants) (β=-0.19; R²=0.17; p=0.07). There was a male predominance (65%), and ages ranged from 20-49 years (65%). There was a substantial increase in the number of patients that were cured after treatment (60% to 67%; p<0.001) as well as those tested for HIV (1.9% to 58.5%; p<0.001). During the first decade, clusters with p-values <0.05 included 29% of the total notified cases, and in the second decade, that percentage was 12%. CONCLUSIONS We observed a decreasing trend in incidence, which was significant, and mortality rates, which was not significant. The increased number of laboratory tests performed reflects advances in surveillance, and a reduction in the proportion of cases in primary clusters suggests, among other things, that the disease is spreading across the region.

Soil CO2 efflux in central Amazonia: environmental and methodological effects

Soil respiration plays a significant role in the carbon cycle of Amazonian rainforests. Measurements of soil respiration have only been carried out in few places in the Amazon. This study investigated the effects of the method of ring insertion in the soil as well as of rainfall and spatial distribution on CO2 emission in the central Amazon region. The ring insertion effect increased the soil emission about 13-20% for sandy and loamy soils during the firsts 4-7 hours, respectively. After rainfall events below 2 mm, the soil respiration did not change, but for rainfall greater than 3 mm, after 2 hours there was a decrease in soil temperature and respiration of about 10-34% for the loamy and sand soils, with emissions returning to normal after around 15-18 hours. The size of the measurement areas and the spatial distribution of soil respiration were better estimated using the Shuttle Radar Topographic Mission (SRTM) data. The Campina reserve is a mosaic of bare soil, stunted heath forest-SHF and tall heath forest-THF. The estimated total average CO2 emissions from the area was 3.08±0.8 µmol CO2 m-2 s-1. The Cuieiras reserve is another mosaic of plateau, slope, Campinarana and riparian forests and the total average emission from the area was 3.82±0.76 µmol CO2 m-2 s-1. We also found that the main control factor of the soil respiration was soil temperature, with 90% explained by regression analysis. Automated soil respiration datasets are a good tool to improve the technique and increase the reliability of measurements to allow a better understanding of all possible factors driven by soil respiration processes.

Simulium argentiscutum sp. nov. (Diptera: simuliidae), a member of the S. amazonicum-group of species; description of adults, pupa and larva

The adult, pupal and larval morphology of S. argentiscutum sp. nov., a member of the S. amazonicum-group, is compared with S. amazonicum Goeldi and its distribution, biology and medical importance are discussed. S. argentiscutum is one the most important anthropophilic species in the S. amazonicum-group as it is responsible, together with S. amazonicum, for the transmission of Mansonella ozzardi in Brazil.

New species records for the blackfly (Diptera-Simuliidae) fauna of Argentina with description of adults, pupa and larva of Simulium oyapockense s. l. and S. seriatum

Two blackfly species Simulium (Cerqueirellum) oyapockense Floch & Abonnenc and S. (Hemicnetha) seriatum Knab are recorded from Argentina, representing the most southern register for both species. S. oyapockense is a species epidemiologically very important, as a vector of onchocerciasis in the Amazonian focus. Both species are described and illustrated and their distribution are reported, in similarity to others like S. roraimense Nunes de Mello and S. ganalesense Vargas et al. in reference to S. oyapockense and S. mexicanum Bellardi similar to S. seriatum are discussed.

Some Streblidae and Nycteribiidae (Diptera: Hippoboscoidea) from Maracá Island, Roraima, Brazil

Fourteen species in five genera of Streblidae and two species in two genera of Nycteribiidae, collected in Maracá Island, State of Roraima, Brazil are presented with comments on bat hosts and geographical distribution. A total of 42 specimens of Diptera and 17 bats were captured from 1987 to 1988, integrating the "Maracá Project". All species of ectoparasites represent new geographic records for Roraima.

Simulium lobatoi, new species of blackfly (Diptera: Simuliidae) from the states of Mato Grosso and Goiás, Central Brazil

During studies on the taxonomy of the Simuliidae of Brazil, a new species of Simulium was found. Full descriptions of the adults and pupae of this species are described here, its affinities with other species are discussed and its distribution, biology, and medical importance in Brazil are recorded.

Epidemiological and control aspects of schistosomiasis in Brazilian endemic areas

The present work analyzes the epidemiology of schistosomiasis in Brazil, its expansion, the attempts to control the disease, and the overall difficulties. The authors present the distribution of schistosomiasis intermediary hosts in Brazil, the migration routes of the human population, and disease distribution in highly and lowly endemic areas and isolated foci. They also analyze the controlling programs developed from 1977 to 2002, indicating the prevalence evolution and the reduction of disease morbi-mortality. In addition, the authors also evaluate controlling methods and conclude that: (a) no isolated method is able to control schistosomiasis, and every controlling program should consider the need of a multidisciplinary application of existing methods; (b) in long term, basic sanitation, potable water supply, as well as sanitary education, and community effective participation are important for infection control; (c) in short term, specific treatment at endemic areas, associated with control of intermediary hosts at epidemiologically important foci, are extremely relevant for controlling disease morbidity, although not enough for interrupting infection transmission.

Variability and genetic differentiation among Anopheles (Ano.) intermedius Chagas, 1908 and Anopheles (Ano.) mattogrossensis Lutz & Neiva, 1911 (Diptera: Culicidae) from the Brazilian Amazon

Anopheles (Anopheles) intermedius and Anopheles (Ano.) mattogrossensis are Brazilian anopheline species belonging to the scarcely studied Anopheles subgenus. Few studies have been done on the genetic differentiation of these species. Both species have been found infected by Plasmodium and are sympatric with other anopheline species from the Nyssorhynchus subgenus. Eighteen enzymatic loci were analyzed in larval specimens of An. intermedius and An. mattogrossensis aiming to estimate the variability and genetic differentiation between these species. An. mattogrossensis population showed higher genetic variability (P = 44.4 and Ho = 0.081 ± 0.031) than that of An. intermedius (P = 33.3 and Ho = 0.048 ± 0.021). Most analyzed loci showed genotypic frequencies according to Hardy-Weinberg equilibrium, except for LAP1 and LAP2 in An. intermedius, and EST1 and PGM loci in An. mattogrossensis. The genetic distance between these species (D = 0.683) was consistent with the inter-specific values reported for Anopheles subgenus. We verified that the polymorphism and heterozygosity percentile values found in both species and compared to those in the literature, showed no relation between the level of isozyme variability and geographical distribution. The low variability found in these two species is probably more related to the niche they occupy than to their geographic distribution.

Single and concomitant experimental infectionsby Endotrypanum spp. and Leishmania (Viannia) guyanensis (Kinetoplastida: Trypanosomatidae) in the Neotropical sand fly Lutzomyia longipalpis (Diptera: Psychodidae)

Lutzomyia longipalpis females received single and mixed infections with Endotrypanum and Leishmania. Two biological parameters were analyzed: the percentage of infected females and the distribution of flagellates in the gut of the females. The principal comparisons were performed between (1) two strains of Endotrypanum, (2) cloned versus primary sample of one strain of Endotrypanum, (3) Endotrypanum versus Leishmania guyanensis, and (4) the pattern of flagellates behaviour by optical microscopy in females with single or mixed infection versus the identification of parasites isolated from digestive tracts by isoenzyme electrophoresis. Flagellates of Endotrypanum showed distinct patterns of infection suggesting that there is variation between and within strains. The distribution of Endotrypanum and L. guyanensis differed significantly in relation to the colonization of the stomodeal valve. In co-infection with L. guyanensis, a large number of flagellates were seen to be plentifully infecting the stomodeal valve in significantly more specimens than in females infected by Endotrypanum only. However, the electrophoretic profiles of isoenzymes of parasites recovered from all co-infected specimens corresponded to Endotrypanum. This suggests that the mere correlation sand fly infection-biochemical analysis of isolates may induce parasitological incorrect consideration.

Antiretroviral resistance in individuals presenting therapeutic failure and subtypes of the human immunodeficiency virus type 1 in the Northeast Region of Brazil

This study aimed to analyze human immunodeficiency virus (HIV) mutation profiles related to antiretroviral resistance following therapeutic failure, and the distribution of hiv subtypes in the Northeast Region of Brazil. A total of 576 blood samples from AIDS patients presenting therapeutic failure between 2002 and 2004 were analyzed. The genotyping kit viroSeq® was used to perform viral amplification in order to identify mutations related to hiv pol gene resistance. An index of 91.1% of the patients presented mutations for nucleoside reverse transcriptase inhibitors (nrti), 58.7% for non-nucleoside reverse transcriptase inhibitors (nnrti), and 94.8% for protease inhibitors (pi). The most prevalent mutations were 184V and 215E for nrti, 103N and 190A for nnrti. Most mutations associated with PIs were secondary, but significant frequencies were observed in codons 90 (25.2%), 82 (21.1%), and 30 (16.2%). The resistance index to one class of antiretrovirals was 14%, to two classes of antiretrovirals 61%, and to three classes 18.9%. Subtype B was the most prevalent (82.4%) followed by subtype F (11.8%). The prevalence of mutations related to nrti and nnrti was the same in the two subtypes, but codon analysis related to PI showed a higher frequency of mutations in codon 63 in subtype B and in codon 36 in subtype F. The present study showed that there was a high frequency of primary mutations, which offered resistance to nrti and nnrti. Monitoring patients with treatment failure is an important tool for aiding physicians in rescue therapy.

Polymorphisms of toll-like receptor 2 and 4 genes in Chagas disease

The aim of this study was to test the possible implication of toll-like receptor 2 (TLR2) and TLR4 gene polymorphisms in determining the susceptibility to Chagas' disease. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism in 475 individuals from Colombia, 143 seropositive with chagasic cardiomyopathy, 132 seropositive asymptomatic and 200 seronegative. The TLR2 arginine to glutamine substitution at residue 753(Arg753Gln) polymorphism was absent in the groups analyzed. The TLR4 Asp299Gly and Thr399Ile polymorphisms are in linkage disequilibrium and we observed a very low frequency of these polymorphisms in our study population (2.6% and 1.8% respectively). The overall TLR2 and TLR4 alleles and genotype distribution in seronegative and seropositive were not significantly different. We compared the frequencies between asymptomatic patients and those with chagasic cardiomyopathy and we did not observe any significant differences in the distribution of alleles or genotypes. In summary, this study corroborates the low frequency of TLR2 and TLR4 polymorphisms observed in other populations and suggest that these do not play an important role in Chagas' disease. The validation of these findings in independent cohorts is needed to firmly establish a role for TLR2 and TLR4 variants in Chagas' disease.