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Objective. Estimate seroprevalence, clinical case rate, and proportion of subclinical infections from chikungunya. Methods. A cross-sectional study was conducted in October 2015 at 39 sites distributed across Nicaragua. Demographic and clinical information was compiled through a personal survey. Blood samples were collected to detect chikungunya antibodies using the ELISA inhibition method developed by Nicaragua's National Diagnostic and Reference Center. Results were analyzed using generalized linear models and multilevel Poisson models. Results. A total of 11 722 participants aged >2 years were enrolled and 11 280 samples were processed. National seroprevalence was 32.8% (95% CI [95% confidence interval]: 31.9-33.6), with a clinical case rate of 26.5% (95% CI: 25.7-27.3) and a proportion of subclinical infections of 19.1% (95% CI: 17.8-20.4). Seroprevalence varied among the 39 sites and was greater at sites with higher vector infestation indices. Individually, seroprevalence was higher in participants aged >11 years. Conclusion. Since its introduction, this is the first study on chikungunya seroprevalence in continental Latin America to determine national prevalence, clinical case rate, and proportion of subclinical infections. The study model, employing broad community participation and leadership by the Ministry of Health of Nicaragua, can be an example for conducting similar studies in the region. [ABSTRACT FROM AUTHOR]

Objective. To determine the seroprevalence of dengue fever serotypes in three sanitary districts in the city of Belo Horizonte and investigate the association of seroprevalence with contextual and individual variables. Method. The survey was conducted in the sanitary districts of Venda Nova, Leste and Centro-Oeste between June 2006 and March 2007. All residents aged 1 year or older were eligible for the study. Participants answered a questionnaire and had a 5 mL blood sample collected to determine the presence of anti-dengue types 1, 2, and 3 virus antibodies by seroneutralization. The questionnaire covered demographic aspects, socioeconomic status, physical characteristics of the home, residential mobility between cities, previous history of signs and symptoms associated with dengue fever, and knowledge concerning dengue fever prevention measures, among others. Results. Seroprevalence was 11.9% (95%CI: 9.7-14.6) among the 709 individuals included in the study, and it was not associated with sex, age, family income, and having moved to another town in the past 10 years. Seropositivity was associated with type of construction (apartment or house/shanty, with apartment being a protection factor) and with an elevated health vulnerability index where the dwelling was located. Conclusions. In this study, seroprevalence was lower than in previous studies carried out in mid-size and large Brazilian cities. This suggests that Belo Horizonte has employed efficient control measures. However, heterogeneity within the city was observed in terms of dengue fever transmission, which was largely associated with contextual indicators of vulnerability. The number of susceptibles is still high, and the control of dengue fever remains a difficult public health issue. [ABSTRACT FROM AUTHOR]

bjective. To determine the prevalence of human T-cell lymphotropic virus type I (HTLV-I) infection among patients with lymphoproliferative disorders, as well as among their family members and sexual contacts, at two sentinel sites in Cuba. Methods. An analysis was conducted of all the patients with a presumptive diagnosis of hematological malignancies seen by the hematology departments of the Hospital Hermanos Ameijeiras (HHA), City of Havana, and the Hospital Provincial Comandante Faustino Pérez (HPCFP), Matanza, Cuba, in January 1996-January 1997. HTLV-I seropositivity was determined by ELISA and Western Blot, and infection was confirmed by polymerase chain reaction. The positive patients' family members and sexual contacts were also assessed. The Z-test was used to compare proportions. Results. Seroprevalence of HTLV-I infection in patients with lymphoproliferative disorders was 0.4% higher at the HPCFP than at the HHA (6.1% versus 0.2%, P < 0.001). There were no significant differences in prevalence by age, sex, or skin color. Of the 53 family members and sexual contacts studied, 8 (15.1%) were positive for HTLV-I infection. Conclusion. The prevalence of HTLV-I in the study group was higher than previously found in Cuba. The value of seroepidemiological surveillance through sentinel sites was confirmed. [ABSTRACT FROM AUTHOR]

Objectives. To determine the prevalence of Trypanasoma cruzi antibodies among the population under 18 years of age in the state of Veracruz, Mexico, and to identify risk factors associated with housing conditions and vector presence and distribution. Methods. A cross-sectional, epidemiological study of the population under 18 years of age living in 10 of the 11 health districts of the state of Veracruz, Mexico, from 2000 to 2001. Presence of T. cruzi antibodies was determined by hemagglutination inhibition test (HAl) and enzyme-linked immunosorbent assays (ELISA) of serum samples spotted on filter paper, and confirmed by HAl, ELISA, and indirect immunofluorescence assay (IFA) on serum samples. A questionnaire was administered to determined housing conditions, and entomological indices for triatomines were calculated for both the intra- and peridomiciliary areas. The results were analyzed using bifactorial and multifactorial unconditional logistic regression. Results. Of the 150 individuals presenting an initial reaction, 14 were confirmed positive (5 by HAl, ELISA and IFA; 6 by HAl and ELISA, and 3 by ELISA and IFA), for a total prevalence rate of 0.91% (95% CI: 0.85–0.94). All of the confirmed-positive cases were from five of 14 health districts, with the Tuxpan district having the highest prevalence rate: 5.2% (95%CI: 1.2–9.0). Risk factors included having noticed cracks in the house walls and gaps in the roof. The only species of vector captured was Triotoma dimidiata. The entomologic indices for infestation, colonization, and natural infection were: 10.9%, 50.0%, and 9.0%, respectively. Conclusions. Active, vector-borne transmission of T. cruzi was confirmed in the state of Veracruz, Mexico, with an overall antibody seroprevalence rate of 0.19% among the population under 18 years of age. Seroprevalence rates among this segment of the population, which serves as a sentinel group, should be closely monitored to determine if more stringent methods of vector control and epidemiological surveillance are needed. [ABSTRACT FROM AUTHOR]

Objective. To determine the proportion of postpartum women aged 15–49 in Peru who are susceptible to rubella, in order to help address strategies to eliminate rubella and to prevent congenital rubella syndrome (CRS) in the country. Methods. A cross-sectional survey was conducted during March and April 2003 in six main regional hospitals, in the three geographic regions (coast, mountain, and jungle) of Peru. For the postpartum women who provided written informed consent, a questionnaire was administered and a blood specimen was collected. Sera were tested for rubella immunoglobulin G (IgG) antibody, using a commercial enzyme-linked immunosorbent serologic assay (ELISA) kit. Univariate, bivariate, and multivariate analyses were carried out to assess risk factors for susceptibility. Results. In total, 1 236 postpartum women were enrolled. The overall proportion of IgG-antibody negative women was 12.8% (95% confidence interval (CI): 10.9%–14.6%). Bivariafe analysis found the following variables associated with susceptibility: living in the jungle region (odds ratio (OR) = 1.65; 95% CI: 1.13–2.42); age < 19 years (OR = 2.02; 95% CI: 1.35–3.03); being a housewife (OR = 1.69; 95% CI: 1.12–2.55); and having ≤ 11 years of education (OR = 2.12; 95% CI :1.20–3.75). Multivariate analysis found the following variables were associated with susceptibility: living in the jungle region (OR = 1.67; 95% CI: 1.13–2.46); age < 19 years (OR = 1.62; 95% CI: 1.07–2.47); having < 4 children born alive (OR = 1.85; 95% CI: 1.00–3.40); and having ≤ 11 years of education (OR = 2.07; 95% CI: 1.1 6–3.71). Conclusions. The proportion of postpartum women at the study sites who were found to be susceptible to rubella was 12.8%, placing Peru among the countries facing a moderate level of risk for the occurrence of CRS cases. The findings suggest the need to also provide the rubella vaccine to other population groups, especially women of childbearing age. [ABSTRACT FROM AUTHOR]

Objectives. To conduct a study in a small rural hospital located in the state of Chiapas, Mexico, to: (1) examine the prevalence of chagasic cardiomyopathy among patients with the diagnosis of congestive heart failure and (2) assess the prevalence of positive serologic results in blood donors in the hospital, in an attempt to ascertain whether Chagas' disease remains an important cause of heart failure at least in some areas of Mexico. Methods. The study of patients with cardiomyopathy was conducted by retrospective chart review of patients with the diagnosis of congestive heart failure treated at the hospital during the years 2000-2002. With the blood donors, the results of their serologic screening were reviewed for a six-month period beginning in April 2002. Serologic testing was done in both groups with either indirect hemagglutination (IHA) or enzyme-linked immunosorbent assay (ELISA), or with both. Results. Of 67 patients with heart failure and no risk factors for other causes of heart failure, 40 of them had serologic tests performed. Thirty-three of these 40 (82.5%) were positive by ELISA, IHA, or both. With 97 blood donors, one or both serologic tests were positive in 17 of them (17.5%). Conclusions. This research adds to the evidence that Chagas' disease continues to be a major cause of heart failure in some areas of Mexico and that there continues to be a risk of transmission by blood transfusion if donated blood is not consistently screened. [ABSTRACT FROM AUTHOR]

Objective. Little is known about the prevalence and distribution of Kaposi's sarcoma-associated herpesvirus (KSHV) infection in the Caribbean. The aim of this study was to determine rates of KSHV seropositivity in various populations in Cuba. Methods. During the years 1998 to 2002 we screened serum samples from 410 subjects in Cuba. Serologic screening for KSHV antibodies was a two-step process using (1) indirect immuno-fluorescence assay (IFA) specifically reactive to the KSHV latency-associated nuclear antigen (LANA) encoded by open reading frame 73 (ORF73), and (2) confirmatory immuno-blot using recombinant KSHV ORF65.2, a lyrically expressed, 20-kilodalton protein as the target antigen. Five different populations were studied: (1) 45 AIDS patients with Kaposi's sarcoma (AIDS-KS), (2) 154 HIV-1-infected patients without clinical evidence of KS, (3) 171 HIV-negative blood donors, (4) 27 consecutive kidney transplant recipients, who were HIV-negative, and (5) 13 contacts (sexual contacts or relatives) of the AIDS-KS-affected patients. Results. Among the 45 AIDS-KS subjects, 35 of them (77.8%) were KSHV-seropositive. Thirty-two of the 154 HIV-positive patients without KS (20.8% of them) were KSHV-seropositive, and 6 of the 13 contacts of KS-affected patients (46.2% of them) were infected with KSHV. In contrast to other researchers, we did not find in the populations that we studied in Cuba that KSHV seropositivity was associated with male homosexual or bisexual activity. We found high KSHV seropositivity rates among women reporting sexual contact with bisexual men and among men who had acquired an HIV infection in Africa. There were low rates of KSHV infection among the blood donors (1.2%) and the renal transplant recipients (0.0%). The low rates of KSHV infection that we found among the non-HIV-infected populations in Cuba are similar to patterns found in populations in Europe and in the United States. Conclusions. Together with similar results from Brazil... [ABSTRACT FROM AUTHOR]

Objectives. To estimate the proportion of individuals seronegative for measles antibody among blood donors from a blood bank in the city of Rio de Janeiro, Brazil, and to describe their social and demographic characteristics, with the goal of exploring the potential use of plasma banks to supplement serological surveillance with relevant data in order to support the program of measles elimination in the city of Rio de Janeiro and elsewhere. Methods. Plasma samples from 1 101 consecutive blood donations made in November 2000 at HEMORIO, the largest blood bank in the state of Rio de Janeiro, were tested for measles immunoglobulin G, using a commercial enzyme immunoassay and a plaque reduction neutralization test. We calculated the proportion (and 95% confidence interval (CI)) o seronegative for measles antibody for the total sample of blood donors and also for subgroups categorized by age, sex, neighborhood of residence, education, and occupation. We used the chi-square test to assess the statistical significance of differences in proportions and linear trends in proportions. Results. Of the total group of blood donors, 6.9% of them (95% CI: 5.4%-8.4%) were seronegative for measles. Women had a higher proportion (10.1%; 95% CI: 6.8%-13.4%) of seronegative results than did men (5.6%; 95% CI: 4.0%-7.2%). In terms of age, 86.8% of seronegative individuals were born between 1971 and 1982. Seronegativity was inversely proportional to age (chi-square = 58.0; P < 0.0001). With regard to occupation, students had the highest proportion of seronegative individuals (17.8%). In terms of education, most of the susceptible persons were in the categories of "incomplete university degree" or "incomplete high school." For the various areas of residence the proportions ranged from 2.1% to 11.4%. Conclusions. Blood bank plasma may constitute a useful and convenient source of complementary data for serological surveillance in adults of measles and other infections for which... [ABSTRACT FROM AUTHOR]

Background: The aim of the study was to estimate the seroprevalence and risk factors of toxoplasmosis in pregnant women in the department of Annaba, Algeria., Methods: We performed a cross-sectional study with analytical purposes. The study was collaboration between the laboratory of Parasitology-Mycology, Faculty of Medicine of Annaba and Parasite Biology Department at the Pasteur Institute of Algeria. A total of 1028 pregnant women who underwent prenatal diagnosis/visit were included over a period of 4 years from January 2006 to December 2009. Immunoglobulin G and M were assayed, using the microparticle enzyme method. The avidity test was used to determine the date of contamination according to age of pregnancy. Search for the parasite was made by inoculation of the placenta and cord blood in white mice. The study compared mother-to-child serological profiles using Western Blot (WB) IgG and IgM. Direct (not well-cooked meat) and indirect (presence of cat, gardening) indicators were recorded to search for parasite exposure., Results: Seroprevalence was 47.8 % (95 % CI: 44.8 to 51.0) and the rate of active toxoplasmosis was 1.1 % (95 % CI 0.6 to 1.8). According to their immune status, this was the first serology for 41 % (CI95 %: 38.0-44.0) of women; 12 % (CI95 %: 10.5-14.6) of primiparous women had only one serology test during their entire pregnancy. Major risk factors were consumption of poorly-cooked meat and exposure to cats., Conclusion: Toxoplasmosis during pregnancy is a serious issue and an effective prevention program is needed., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Hepatitis E virus (HEV) infection constitutes a leading cause of waterborne epidemics of acute hepatitis in developing countries, mostly in Southeast Asia and Africa. In these areas, the seroprevalence for HEV antibodies in the general population may be as high as 20-40%, and HEV genotypes 1 or 2 are responsible for an estimated 20 million incident infections every year. Most cases are non or mildly symptomatic, but mortality may rise to 30% in certain risk groups as the elderly, patients with chronic conditions, or pregnant women.