Incidence and risk factors for Dengue virus (DENV) infection in the first 2 years of life in a Brazilian prospective birth cohort.

This study assessed the incidence and risk factors for dengue virus (DENV) infection among children in a prospective birth cohort conducted in the city of Recife, a hyperendemic dengue area in Northeast Brazil. Healthy pregnant women (n = 415) residing in Recife who agreed to have their children followed were enrolled. Children were followed during their first 24 months of age (May/2011-June/2014), before the 2015 Zika virus outbreak. DENV infection was detected by reverse-transcriptase polymerase chain reaction and/or serology (anti-DENV IgM/IgG). The incidence rates per 1000 person-years (py) and its association with risk factors by age bands (0-12, >12-30 months) were estimated through Poisson regression models. Forty-nine dengue infections were detected; none progressed to severe forms. The incidence rates were 107·6/1000py (95% CI 76·8-150·6) and 93·3/1000py (95% CI 56·1-154·4) in the first and second years of age, respectively. Male children (risk ratios (RR) = 2·33; 95% CI 1·09-4·98) and those born to DENV-naïve mothers (RR = 2·42; 95% CI 1·01-5·80) were at greater risk of infection in the first year of age. In the second year, children born to Caucasian/Asian descent skin colour mothers had a threefold higher risk of infection (RR = 3·34; 95% CI: 1·08-10·33). These data show the high exposure of children to DENV infection in our setting and highlight the role of biological factors in this population's susceptibility to infection.

Force of infection of dengue serotypes in a population-based study in the northeast of Brazil.

This study investigated anti-dengue serotype-specific neutralizing antibodies in a random sample of dengue IgG-positive individuals identified in a survey performed in a hyperendemic setting in northeastern Brazil in 2005. Of 323 individuals, 174 (53.8%) had antibodies to dengue virus serotype 1 (DENV-1), 104 (32.2%) to DENV-2 and 301 (93.2%) to DENV-3. Monotypic infections by DENV-3 were the most frequent infection (35.6%). Of 109 individuals aged <15 years, 61.5% presented multitypic infections. The force of infection estimated by a catalytic model was 0.9%, 0.4% and 2.5% person-years for DENV-1, DENV-2 and DENV-3, respectively. By the age of 5 years, about 70%, 30% and 40% of participants were immune to DENV-3, DENV-2 and DENV-1, respectively. The data suggest that infection with DENV-1, -2 and -3 is intense at early ages, demonstrating the need for research efforts to investigate dengue infection in representative population samples of Brazilian children during early infancy.

Staphylococcus aureus bacteraemia: incidence, risk factors and predictors for death in a Brazilian teaching hospital.

The aim of this study was to evaluate the incidence of bloodstream infection due to Staphylococcus aureus and the risk factors for mortality. The design was a two-year retrospective cohort of patients more than one year of age with clinically significant and microbiologically documented bloodstream infection due to S. aureus between January 2000 and December 2001 in a tertiary teaching hospital in midwest Brazil. One hundred and eleven patients were identified with clinically significant and microbiologically confirmed bacteraemia due to S. aureus, accounting for an infection rate of five per 1000 admissions. Nosocomial infections represented 83.8% of cases and meticillin-resistant Staphylococcus aureus (MRSA) accounted for 60.2% of cases. Overall mortality due to S. aureus bacteraemia was 35.1%. Infection due to MRSA, severity of clinical status (severe sepsis or septic shock) and inadequate initial antimicrobial therapy were identified by univariate analysis as predictors of mortality. After Cox regression analysis, severity of clinical manifestations [hazard ratio (HR) 6.86, 95% confidence interval (CI) 3.05-15.43] and inadequacy of antimicrobial therapy (HR 2.27, 95%CI 1.02-5.09) remained as risk factors for mortality. Early diagnosis of bacteraemia should be sought in order to implement adequate treatment before the onset of severe sepsis and septic shock, thus reducing the mortality rate.

Haemophilus influenzae resistance in Latin America: systematic review of surveillance data.

Haemophilus influenzae is a relevant cause of morbidity and mortality among children under 5 years of age in the developing world. In Latin America, H. influenzae type b (Hib) conjugate vaccine and surveillance of H. influenzae antimicrobial susceptibility have been implemented in recent years. We have undertaken a systematic review and a pooled analysis on H. influenzae antimicrobial resistance, including reports of 15 Latin America countries over a 10-year period (1990-2000). We have found that 450 (21.4%) of 2,100 invasive isolates were beta-lactamase producers compared to 145 (14.5%) of 998 isolates of noninvasive isolates (p < 0.05). Ampicillin resistance was detected among 783 (21.9%) of 3,577 invasive isolates compared to 111 (17.2%) of 646 noninvasive strains (p < 0.05). In contrast, 568 (41.9%) of 1,355 noninvasive strains were trimethoprim-sulfamethoxazole (TMP-SMX) resistance against 241 (26.9%) of 897 invasive ones (p < 0.05). Therefore, TMP-SMX resistance was more common in nonsterile fluids than in sterile fluids. Over time, rates of beta-lactamase-producing strains were stable in Brazil and Mexico, whereas rates of TMP-SMX resistance were increasing in Brazil. It is predictable that following the Hib immunization, Latin America countries will be faced with increased nontypeable H. influenzae infection. Although standing by the nontypeable H. influenzae vaccine, in this novel epidemiological scenario of post-Hib vaccination in Latin America settings there is a need to improve H. influenzae resistance monitoring to guide clinicians to choose efficacious antimicrobial therapy.

Risk factors for Trypanosoma cruzi infection among children in central Brazil: a case-control study in vector control settings.

This population-based case-control study was conducted in northern Goias State, central Brazil, in rural settings under vector control surveillance. One hundred forty-nine children seropositive for Trypanosoma cruzi antibodies, selected in a cross-sectional survey carried out in village schools, were compared with 298 seronegative classmate controls matched for age, sex, and place of residence. Information on potential environmental, familiar, and social economic risk factors for T. cruzi infection was collected during household visits, and interviews with parents and entomologic inspections of domestic and peridomestic environments were conducted. The presence of triatomines in dwellings or evidence of triatomine colonization was found to be statistically associated with seropositivity in children. The presence of exuviae and a report of triatomines indoors or outdoors by householders in the past were strong predictors of an infected child. Children from seropositive mothers had a 3.9-fold increase in the risk of having anti-T. cruzi antibodies after adjusting for the confounding variables, including triatomine capture, mother's age, and family size in multivariate analysis. Parent's report of vector presence showed a 97.7% sensitivity in identifying a dwelling with at least one seropositive child. The possibility of transplacental T. cruzi transmission and its implication for Chagas' disease control were considered.

Evaluation of risk factors for house infestation by Triatoma infestans in Brazil.

An active entomologic survey was conducted by a team of trained health workers in a rural area endemic for Chagas' disease in central Brazil. They used pyrethrum as a flushing agent and 4,232 houses were inspected for triatomine bugs both inside and in the immediate environs. Houses with Triatoma infestans or evidence of an established colony were identified and defined as infested houses (cases). The building and environmental characteristics of 161 randomly selected infested houses were compared with 161 matched, noninfested houses (controls) that were the shortest distance from the infested house. Domestic and peridomestic potential risk factors associated with house infestation by Triatoma infestans were assessed by logistic regression analysis. Incomplete house construction (odds ratio [OR] = 2.5, 95% confidence interval [CI] = 1.5-4.1) was confirmed as a risk factor related to the presence or evidence of Triatoma infestans in the dwellings. The study also disclosed a statistically significant association between the presence of rats (OR = 1.6, 95% CI = 1.1-2.6) and indoor crop storage (OR = 2.3, 95% CI = 1.1-5.2) and house infestation. Further experimental field studies using tagged rodents should be conducted to assess their epidemiologic role in the domestic chain of Trypanosoma cruzi transmission.

Early electrocardiographic abnormalities in Trypanosoma cruzi-seropositive children.

As part of a major epidemiologic study on Chagas' disease, we compared the prevalence of electrocardiographic (ECG) abnormalities among 141 school children 7-12 years of age and seropositive for Trypanosoma cruzi, and 282 age-, sex-, and school-matched seronegative children in an endemic area in Brazil. The prevalence of ECG abnormalities was 11.3% among seropositive children and 3.5% among seronegative children (odds ratio = 3.5, 95% confidence interval [CI] = 1.5-8.4). The prevalence rate of ECG alterations was 10.7% for seropositive males versus 8.9% for seropositive females. Complete right bundle branch block (CRBBB), which is highly suggestive of Chagas' disease cardiopathy, was diagnosed in nine (6.4%) seropositive children and in only one (0.3%) seronegative child (odds ratio = 18.5, 95% CI = 2.3-146.5, attributable fraction = 58.3%). Five incident new cases of CRBBB were diagnosed after a 36-month follow-up of seropositive children who were enrolled in an independent clinical field trial. No case of frequent and/or multifocal ventricular premature beats was found in the cohort of children. The surprisingly high frequency of early ECG abnormalities, which indicates a rapid evolution from infection to disease, suggests the existence of endemic areas with a particular accelerated disease progression that was not described before. Under such conditions, a public health chemotherapy program focusing on the treatment of young seropositive children would be recommended.

Prevalence and risk factors for HBV infection among street youth in central Brazil.

PURPOSE: A seroprevalence survey was carried out among 496 street adolescents from 9 to 20 years old in central Brazil to determine the prevalence of hepatitis B (HBV) markers, as well as to assess the role of potential risk factors. RESULTS: The findings reveal that 20.4% of the participants were homeless adolescents without family links, living and/or working on the streets. The age at first sexual intercourse was as low as 9 years old, and approximately 60% of this population had had at least one sexual relationship by the age of thirteen, indicating prepubertal initiation of sexual experiences among street adolescents. 13.5% were HBV marker-positive (anti-HBc) and 2.0% had antigenemia. Street-based youth had a higher HBV marker-positive rate when compared to home-based teens (OR = 4.1, 95% CI: 2.1-8.5) and, similarly, higher HBV prevalence was obtained for those reporting sexual activity versus the group without sexual activity (OR = 2.1, 95% CI: 1.1-3.9), even after adjusting for potential confounders. CONCLUSIONS: We have found that street youth, particularly street-based adolescents, should be considered at-risk group for hepatitis B infection in our region. These findings may be used as a baseline information for policy changes not only in hepatitis B prevention but also to reverse the scenario of adolescents sexual abuse.

[Bacteriologic study of abscesses caused by bites of snakes of the genus Bothrops]. / Estudo bacteriológico de abscessos causados por picada de serpentes do genero Bothrops.

The bacterial flora of 99 cases of abscesses following Bothrops snakebite were analysed. They corresponded to 61.1% of all snakebite abscesses observed in 1030 patients attending the Hospital de Doenças Tropicais de Goiánia in Goiás, Brazil, from January 1984 to April 1988. An exsudate sample of each abscess was examined by Gram stain, culture and susceptibility tests. The Gram negative bacillis, Morganella morganii, Escherichia coli and Providencia sp were the most frequent bacterias isolated. They were identified in 44.4%, 20.2% and 13.1% of the samples respectively. This flora was similar to those described in snake mouth and venom by other researchers. Based on the results of the susceptibility tests the authors suggested the use of chloramphenicol for the treatment of those abscesses which do not respond to simple drainage.

Trends of T. cruzi infection based on data from blood bank screening.

Between October 1988 and April 1989 a cross-sectional survey was carried out in six out of eight blood banks of Goiánia, Central Brazil. Subjects attending for first-time blood donation in the mornings of the study period (n = 1358) were interviewed and screened for T. cruzi infection as a part of a major study among blood donors. Tests to anti-T. cruzi antibodies were performed, simultaneously, by indirect hemagglutination test (IHA) and complement fixation test (CFT). A subject was considered seropositive when any one of the two tests showed a positive result. Information on age, sex, place of birth, migration and socio-economic level was recorded. Results from this survey were compared with seroprevalence rates obtained in previous studies in an attempt to analyse trend of T. cruzi infection in an endemic urban area. The overall seroprevalence of T. cruzi infection among first-time donors was found to be 3.5% (95% confidence interval 2.5%-4.5%). The seroprevalence rate increased with age up to 45 years and then decreased. Migrants from rural areas had higher seroprevalence rates than subjects from urban counties (1.8%-16.2% vs. 0%-3.6%). A four fold decrease in prevalence rates was observed when these rates were compared with those of fifteen years ago. Two possible hypotheses to explain this difference were suggested: 1. a cohort effect related with the decrease of transmission in rural areas and/or 2. a differential proportion of people of rural origin among blood donors between the two periods. The potential usefulness of blood banks as a source of epidemiological information to monitor trends of T. cruzi infection in an urban adult population was stressed.

[Seroprevalence and risk factors for syphilis in prisoners in Goiás, Brazil]. / Soroprevalência e fatores de risco para sífilis em população carcerária de Goiás.

A cross-sectional survey was carried-out among 299 prisoners in the Penitentiary Center of Industrial Activity of Goiás (CEPAIGO), to determine the seroprevalence to T. pallidum and to identify risk factors associated to seropositivity. The seropositivity criterion was a positive VDRL test at any titer. A questionnaire was applied to evaluate the following risk factors: time of imprisonment, clinical evidence of sexually transmitted diseases (STD), history of syphilis or others STD, homo/bisexuality and number of sexual partners. The positive (PPV) and negative (NPV) predictive values of the history of syphilis were calculated. Seroprevalence of 18.4% was found and no difference was detected in the different age groups. The PPV of history of syphilis was 26% indicating that 74% of the individuals who have reported syphilis in the past presented a negative VDRL test. Among all the risk factors studied, homo/bisexuality was the only one with statistically significant association with seropositivity (relative risks 5.7-95% CL1.2-26, p = 0.03). The paper discusses the methodological problems related with the investigation.

Association between leprosy and hepatitis B infection. A survey in Goiânia, central Brazil.

This investigation presents the results of hepatitis B virus screening among leprosy patients conducted in central Brazil as a preliminary information for a HBV vaccination programme. The main objectives were to assess the seroprevalence of HBV serum markers among lepromatous patients and to analyse institutionalization as risk factor for HBV infection in this population. Two groups of lepromatous patients were studied, 83 outpatients and 171 institutionalized ones. Screening for HBV serum markers included the detection of HBsAg, anti-HBc by radioimmune assay (RIA). The prevalence of carrier state (HBsAg) was 4.8% and 8.8% among outpatients and institutionalized, respectively, (p > 0.05). Seroprevalence of exposure (all markers) was statistically significant different between outpatients (16.9%) and institutionalized ones (50.3%). Institutionalized patients had an almost four fold risk of HBV infection when compared to the outpatients, and the highest risks were among patients with more than 21 years of residence in the colony, after adjusting for age and sex.

A randomized clinical trial with high dose of chloroquine for treatment of Plasmodium falciparum malaria in Brazil.

This clinical trial compared parasitological efficacy, levels of in vivo resistance and side effects of oral chloroquine 25 mg/Kg and 50 mg/Kg in 3 days treatment in Plasmodium falciparum malaria with an extended followed-up of 30 days. The study enrolled 58 patients in the 25 mg/Kg group and 66 in the 50 mg/Kg group. All eligible subjects were over 14 years of age and came from Amazon Basin and Central Brazil during the period of August 1989 to April 1991. The cure rate in the 50 mg/Kg group was 89.4% on day 7 and 71.2% on day 14 compared to 44.8% and 24.1% in the 25 mg/Kg group. 74.1% of the patients in the 25 mg/Kg group and 48.4% of the patients in the 50 mg/Kg group had detectable parasitaemia at the day 30. However, there was a decrease of the geometric mean parasite density in both groups specially in the 50 mg/Kg group. There was 24.1% of RIII and 13.8% of RII in the 25 mg/Kg group. Side effects were found to be minimum in both groups. The present data support that there was a high level resistance to chloroquine in both groups, and the high dose regimen only delayed the development of resistance and its administration should not be recommended as first choice in malaria P. falciparum therapy in Brazil.

Risk factors and prevalence of antibodies against hepatitis A virus (HAV) in children from day-care centers, in Goiania, Brazil.

A seroepidemiologic survey about hepatitis A virus (HAV) infection was carried out in a group comprising 310 children, ranging in age from 3 months to 9 years, from day-care centers, in Goiania, a middle sized city in the central region of Brazil. The biomarkers employed in the investigation of previous infection include total IgG and IgM anti-HAV antibodies, and for the detection of more recent infection, IgM anti-HAV antibodies were analyzed. The study was performed in 1991 and 1992. According to the results, 69.7% of the children presented total IgG/IgM anti-HAV antibodies, with 60% of the group in the age range of 1 to 3 years. Among 10 day-care centers analyzed, the prevalence of the biomarker IgM anti-HAV was 3.2%, with an uniform distribution of the cases in the group of children ranging in age from 1 to 4 years. Multivariate analysis was performed to investigate the sociodemographic factors that could influence the results. It was verified that the risk for the infection increased with the length of the attendance in the day-care centers, i.e., the risk for children with attendance of one year or more was 4.7 times higher, when compared with children with one month attendance (CI 95% 2.3-9.9). According to the results, hepatitis A is an endemic infection in day-care centers in the study area. The length of attendance in the day-care settings was demonstrated to be a risk factor for the HAV infection. Such findings suggest that if hepatitis A vaccination becomes available as a routine policy in our region, the target group should be children under one year. Moreover, those children should receive the vaccine before they start to attend the day-care centers.

Immunogenicity of low-dose intramuscular and intradermal vaccination with recombinant hepatitis B vaccine.

The study is a randomized trial using recombinant DNA vaccine to determine whether an intramuscular 10 micrograms dose or intradermal 2 micrograms induces satisfactory anti-HBs levels compared to the standard dose of intramuscular 20 micrograms. Participants were 359 healthy medical and nurse students randomly allocated to one of the three groups: Group I-IM 20 micrograms; Group II-IM 10 micrograms; Group III-ID 2 micrograms at 0, 1 and 6 months. Anti-HBs titres were measured after complete vaccine schedule by ELISA/Pasteur. Baseline variables were similar among groups and side effects were mild after any dose. Vaccines in the IM-10 micrograms group had seroconversion rate and geometric mean titre (GMT 2344 IU L-1), not significant different from the IM-20 micrograms group (GMT 4570 IU L-1). On the contrary, 21.4% of the ID-2 micrograms recipients mount antibody concentration below 10 IU L-1 and GMT of 91 IU L-1, a statistically significant difference compared with the standard schedule IM-20 micrograms (p < 0.001). A three dose regimen of half dose IM could be considered an appropriate schedule to prevent hepatitis B in young health adults which is of relevance to the expansion of hepatitis B vaccine programme.

[Seroepidemiology of hepatitis A virus infection in street children of Goiânia-Goiás]. / Soroepidemiologia da infecção pelo vírus da hepatite A em "meninos de/na rua" de Goiânia-Goiás.

A cross-sectional study was performed to determine the age-prevalence of hepatitis A virus (HAV) among street youth from Goiania city--Central Brazil, and to determine if any risk factors could be identified. The surveys were conducted between 1991/1992. The street youth were 397 individuals aged 7 to 21 years old living in institutions and teenagers working at streets. Then, 313 adolescents working at streets and with family links, and 84 institutionalized ones without family were screened for antibodies against HAV. Prevalences ranged from 80.0% to 92.2% to total anti-HAV and there was not a statistically significant trend of positivity with age in this group. Univariate analysis for risk factors associated with HAV infection was performed with no statistically significant difference for adolescents working at streets and living with parents, and street youth with family links. Economic variables were not statistically associated with seropositivity, probable due to homogeneous characteristics of the group. This study disclosed that street youth have a high rate of HAV infection. These findings do not suggest differences between subgroups of populations in acquiring immunity to HVA. The public health implication and the need of screening other subgroups of population of the same city were suggested in order to discuss vaccine strategy in underdeveloped countries.

[Seroepidemiology for the hepatitis B virus (HBV) in pregnant women/parturients and its transmission to newborns in Goiânia, GO]. / Soroepidemiologia para o vírus da hepatite B (VHB) em gestantes/parturientes e sua transmissão para recém-nascidos em Goiânia-GO.

In order to detect hepatitis B virus (HBV), 1459 serum samples from pregnant/parturient women were collected at two public hospitals in Goiânia, GO. These samples were tested by enzyme linked immunosorbent assay for HBsAg and anti-HBs. 109 (7.5%) serum samples were positive. Eight (0.5%) sera were positive for HBsAg and 101 (7.0%) for anti-HBs. Viral positivity for both HBsAg and anti-HBs were observed in women which age ranged from 15 to 30 years. Four newborns from HBsAg positive mothers were submitted to the treatment with HBV vaccine (Engerix B) and with hyperimmune gammaglobulin (HBIG, Abbott Laboratories, Brazil). Cord blood from one of the newborns was positive for HBsAg. A positive association was found between hepatitis B and sexually transmitted infections and blood transfusion. These results emphasize the need for prenatal screening for HBV in pregnant women and treatment of the newborns from AgHBs-positive mothers.

An epidemiological approach to study congenital Chagas' disease.

Transplacental transmission of Trypanosoma cruzi has been the focus of much attention in highly endemic areas in South America. Frequency of congenital transmission and factors associated with risk of it are still not well understood. Parasite strains may account for part of the geographical variation observed. Methodological differences between the studies do not permit a combined interpretation of results. This paper examines the epidemiological data available from Brazil, Bolivia, and Argentina and discusses possible epidemiological study design to investigate risk factors for transmission.

[Differential patterns of neonatal and post-neonatal mortality rates in Goiânia, Brazil, 1992-1996: use of spatial analysis to identify high-risk areas]. / Diferenças no padrão de ocorrência da mortalidade neonatal e pós-neonatal no Município de Goiânia, Brasil, 1992-1996: análise espacial para identificação das áreas de risco.

The aim of this study was to investigate the spatial pattern of neonatal and post-neonatal mortality in the city of Goiânia, Central Brazil. Analyses were based on linked birth and death certificates relating to 101,000 in-hospital live births from mothers residing in the city of Goiânia over the 1992-1996 period. Overall neonatal and post-neonatal mortality probabilities were calculated using the linked database. The empirical Bayes method was applied to smooth the estimated rates and minimize random fluctuation. Spatial units of analysis were 65 urban districts, corresponding to the urban planning sectors. The following exploratory spatial analyses were applied: "global" Moran's I statistic, local Moran LISA map, and Gi* local statistics. For both neonatal and post-neonatal mortality there was statistically significant spatial autocorrelation. Results of post-neonatal mortality showed a high-risk cluster located on the outskirts of the city. For the neonatal period, a heterogeneous mortality pattern was found with high-risk districts in all regions, including central areas.