Reliability of current estimates of schistosomiasis prevalence in the Rainforest Zone of the state of Pernambuco, Northeastern Brazil

The Program for Schistosomiasis Control within the Unified Health System (PCE-SUS) was implemented by 1999 in the Rainforest Zone or "Zona da Mata" of Pernambuco (ZMP) aiming to carry out biennial stool surveys of whole populations through municipal health organs followed by treatment of the positives through the local units of the Family Health Program (PSF). Yearly reports from the Health Department of Pernambuco State (SES/PE) from 2002 to 2004 on the PCE-SUS surveys were assessed to evaluate whether the current estimates of prevalence in the municipalities of the ZMP are based on reliable samples so as to allow considerations on the real situation of schistosomiasis in that area. The surveys carried out in that period did not follow the major principles underlying sampling design, thus posing problems in both precision and validity of the estimates. Only 12 out of 43 municipalities had minimally reliable estimates: five with moderate prevalence (10-50%) and seven with low prevalence (< 10%). Surveys with appropriate sampling procedures aimed either at representative target groups (school-aged children) or communities are recommended for the ZMP and other endemic areas not only to provide reliable information on the current situation of schistosomiasis but also to plan adequate control strategies.

Analysis and estimative of schistosomiasis prevalence for the state of Minas Gerais, Brazil, using multiple regression with social and environmental spatial data

The aim of this work is to establish a relationship between schistosomiasis prevalence and social-environmental variables, in the state of Minas Gerais, Brazil, through multiple linear regression. The final regression model was established, after a variables selection phase, with a set of spatial variables which contains the summer minimum temperature, human development index, and vegetation type variables. Based on this model, a schistosomiasis risk map was built for Minas Gerais.

Caries prevalence in skeletal series: is it possible to compare?

Because of the relationship with subsistence, dental caries is a central issue in paleopathological research. Usually, comparisons between caries prevalence exhibited in different skeletal series are made. Dietary variation is the most common explanation for cavities prevalence. The aim of this paper is to verify if it is possible to compare caries prevalence reported on papers for archaeological skeletal series. Another goal is to determine if other factors besides diet are implicated in dental cavity prevalence explanation. Twenty six papers about dental health with caries prevalences published from 1999 to 2004 were analyzed for completeness. This assessment includes carious lesion diagnosis and characteristics, age, sex and size characteristics of samples, and prevalence calculation method. The majority of the analyzed papers do not provide adequate information in the topics listed above. Only very few implicated factors other than diet as a contributor to caries lesions development.

Low prevalence of hepatitis C virus infection in Amerindians from Western Venezuela

Previous studies have not found hepatitis C virus (HCV) infection in Amerindians from Western Venezuela. A survey of 254 Bari and Yukpa natives aged 10-60 years (mean ± SD age = 35 ± 5.4 years) from four communities, two Bari and two Yukpa, in this area were studied to assess the prevalence of antibodies to HCV (anti-HCV) and HCV RNA among these indigenous populations. Serum samples were examined initially for anti-HCV by a four generation enzyme-linked immunosorbent assay (ELISA). Reactive samples were then tested using a third generation recombinant immunoblot assay (RIBA-3). Viral RNA was investigated in all immunoblot-reactive samples by a nested polymerase chain reaction (PCR) method. Six (2.3%) of 254 natives were positive by ELISA, one (2.2%) of these reactive samples were positive by RIBA, and four (1.5%) were indeterminate. Only two (0.8%) were positive by PCR, corresponding to 1 (2.1%) of 47 inhabitants of a Yukpa community and to 1 (2.2%) of 45 subjects of a Bari community. Iatrogenic is thought to play a role in acquisition of the infection. The findings indicate a HCV focus of low endemicity and are compatible with a low degree of exposures of the natives to the virus. Studies are necessary to assess the risk factors for infection in these Amerindians.

Prevalence of hepatitis A virus infection in Afro-Brazilian isolated communities in Central Brazil

To investigate hepatitis A virus (HAV) infection rates among isolated African-descendant communities in Central Brazil, 947 subjects were interviewed about demographic characteristics in all 12 isolated Afro-descendant communities existing in the state of Mato Grosso do Sul, Central Brazil, between March 2002 and November 2003. Blood samples were collected and sera were tested for HAV antibodies (total and IgM anti-HAV) by enzyme-linked immunosorbent assay. The overall prevalence of HAV infection was 75.6% (95% CI: 72.7-78.3), ranging from 55.4 to 97.3%, depending on the communities studied. The prevalence of anti-HAV increased significantly with age, from 13.8% in the age 0-5 age group to 96.6% in those older than 40 years. The findings point out an intermediate endemicity of HAV infection in some Afro-Brazilian isolated communities in Central Brazil. In addition, the high proportion of susceptible young subjects could be target of future HAV vaccination programs.

Prevalence of oral hairy leukoplakia and epithelial infection by Epstein-Barr virus in pregnant women and diabetes mellitus patients: cytopathologic and molecular study

Oral hairy leukoplakia (OHL) is generally reported in patients with severe immunosuppression, except for a few cases in individuals with moderate degree of immunodeficiency. It is a white lesion that appears mainly in the lateral border of the tongue, caused by Epstein-Barr virus (EBV). The nuclear changes caused by EBV (Cowdry A inclusion, ground glass and nuclear beading), observed in cytopathology, are specific and enough for the definitive diagnosis of OHL, independent of the identification of the virus. Here we investigated the prevalence of OHL and the presence of EBV-DNA in the lateral borders of the tongue from 90 pregnant women, 90 diabetes mellitus (DM) patients, 30 healthy individuals (negative group) and 30 HIV+ with OHL (positive group). Smears were analyzed by cytopathology and polymerase chain reaction (PCR). A case of subclinical OHL and candidiasis was identificated in a DM patient by cytopathologic analysis. PCR results demonstrated EBV-DNA in 65% of the pregnant women, in 35% of DM patients, and in 20% of the healthy individuals. We concluded that DM patients can develop OHL with a low prevalence. Furthermore, the prevalence of the EBV in lateral border of the tongue is larger in pregnant women than in healthy individuals.

Urban malaria in the Brazilian Western Amazon Region I: high prevalence of asymptomatic carriers in an urban riverside district is associated with a high level of clinical malaria

Cross sectional studies on malaria prevalence was performed in 2001, 2002, and 2004 in Vila Candelária, an urban riverside area of Porto Velho, Rondônia, in the Brazilian Western Amazon, followed by longitudinal surveys on malaria incidence. Vila Candelária is a working class district, provided with electricity, water supply, and basic sanitation. Previous preliminary surveys indicated high malaria incidence in this community. At the end of year 2000 regular diagnostic and treatment measures for malaria were introduced, with active search of febrile cases among residents. Despite of both rapid treatment of cases and relative good sanitary and housing conditions, the malaria incidence persisted at high levels during the following years with an annual parasite index of 150 to 300/1000 inhabitants. Parasite surveys in 2001, 2002, and 2004 achieved through microscopy and polymerase chain reaction to diagnose malaria showed a constant high prevalence of asymptomatic carriers for both Plasmodium falciparum and P. vivax parasites. It was concluded that asymptomatic carriers represent an important reservoirs of parasites and that the carriers might contribute to maintaining the high level of transmission. Comparing our findings to similar geo-demographic situations found in other important urban communities of the Brazilian Amazon, we propose that asymptomatic carriers could explain malaria's outbreaks like the one recently observed in Manaus.

Congenital hydrocephalus--prevalence, prenatal diagnosis and outcome of pregnancy in four European regions.

OBJECTIVE: To describe prevalence, prenatal diagnosis and outcome for fetuses and infants with congenital hydrocephalus. METHODS: Data were taken from four European registries of congenital malformations (EUROCAT). The registries included are based on multiple sources of information and include information about livebirths, fetal deaths with GA > or = 20 weeks and terminations of pregnancy for fetal anomaly (TOPFA). All cases from the four registries diagnosed with congenital hydrocephalus and born in the period 1996-2003 were included in the study. Cases with hydrocephalus associated with neural tube defects were not included in the study. RESULTS: Eighty-seven cases with congenital hydrocephalus were identified during the study period giving an overall prevalence of 4.65 per 10,000 births. There were 41 livebirths (47%), four fetal deaths (5%) and 42 TOPFA (48%). Nine percent of all cases were from a multiple pregnancy. Additional non-cerebral major malformations were diagnosed in 38 cases (44%) and karyotype anomalies in eight cases (9%). Median GA at TOPFA was 21 weeks. Among livebirths 61% were diagnosed prenatally at a median GA of 31 weeks (range 17-40 weeks) and median GA at birth was 37 weeks. Fourteen liveborn infants (34%) died within the first year of life with the majority of deaths during the first week after birth. CONCLUSION: Congenital hydrocephalus is a severe congenital malformation often associated with other congenital anomalies. CH is often diagnosed prenatally, although sometimes late in pregnancy. A high proportion of affected pregnancies result in termination for severe fetal anomaly and there is a high mortality in livebirths.

Prevalence and level of antibodies to the circumsporozoite protein of human malaria parasites in five states of the Amazon region of Brazil

The aim of this study was to determine the prevalence of malaria infection and antibodies against the repetitive epitopes of the circumsporozoite (CS) proteins of Plasmodium falciparum, P. malariae, P. vivax VK210, P. vivax VK247, and P. vivax-like in individuals living in the states of Rondônia, Pará, Mato Grosso, Amazonas, and Acre. Active malaria transmission was occurring in all studied sites, except in Acre. P. falciparum was the predominant species in Pará and Rondônia and P. vivax in Mato Grosso. Infection by P. malariae was low but this Plasmodium species was detected in Rondônia (3.5%), Mato Grosso (2.5%), and Pará (0.8%). High prevalence and levels of serological reactivity against the CS repeat peptides of P. falciparum were detected in Rondônia (93%) and Pará (85%). Sera containing antibodies against the CS repeat of P. malariae occurred more frequently in Rondônia (79%), Pará (76%), and Amazonas (68%). Antibodies against the repeat epitope of the standard CS protein of P. vivax VK210, P. vivax VK247, and P. vivax-like were more frequent in Rondônia, Pará, and Mato Grosso. The high frequency of reactions to P. malariae in most of the areas suggests that the infection by this Plasmodium species has been underestimated in Brazil.

Effects of timber harvest on phlebotomine sand flies (Diptera: Psychodidae) in a production forest: abundance of species on tree trunks and prevalence of trypanosomatids

The Amazon forest is being exploited for timber production. The harvest removes trees, used by sand flies as resting sites, and decreases the canopy, used as refuges by some hosts. The present study evaluated the impact of the timber harvest, the abundance of sand flies, and their trypanosomatid infection rates before and after selective logging. The study was accomplished in terra-firme production forest in an area of timber harvest, state of Amazonas, Brazil. Sand fly catches were carried out in three areas: one before and after the timber harvest, and two control areas, a nature preservation area and a previously exploited area. The flies were caught by aspiration on tree trunks. Samples of sand flies were dissected for parasitological examination. In the site that suffered a harvest, a larger number of individuals was caught before the selective extraction of timber, showing significant difference in relation to the number of individuals and their flagellate infection rates after the logging. The other two areas did not show differences among their sand fly populations. This fact is suggestive of a fauna sensitive to the environmental alterations associated with selective logging.

Prevalence of HIV type 1 drug resistance mutations in treatment-naïve and experienced patients from resource-limited settings with universal access to antiretroviral therapy: a survey in two small Brazilian cities

Concerns have been raised that universal availability of antiretroviral agents in resource-limited settings might lead to the emergence and spread of resistant strains. We present the largest survey on human immunodeficiency virus type 1 (HIV-1) resistance among treatment-naïve and experienced patients followed in small, relatively underprivileged cities in Brazil with universal availability to standard of care antiretroviral combinations. Samples were collected between 2004 and 2006 from 95 patients followed in the cities of Saquarema and Santo Antonio de Pádua, state of Rio de Janeiro. A proviral fragment encompassing protease and reverse transcriptase (RT) regions was generated and drug susceptibility level was inferred. Among 50 strains from drug-naïve subjects, one (2%) had intermediate-level resistance to RT inhibitors. Among 38 patients on therapy as of sampling, 28 (73.7%) had plasma viral load (PVL) below detection limit (26 of whom without evidence of resistance mutations) and 11 (28.9%) harbored strains with reduced susceptibility. Only two strains harbored both protease and RT inhibitor mutations. Among seven patients who were off-treatment as of sampling, two (28.5%) harbored strains with reduced susceptibility to RT inhibitors. The relatively high frequency of undetectable PVL among patients on treatment and the overall low prevalence of resistance-associated mutations are reassuring. Continued surveillance, however, is necessary.

Prevalence, genotypes and risk factors associated with hepatitis C virus infection in hemodialysis patients in Campo Grande, MS, Brazil

A survey was conducted among the hemodialysis units of the city of Campo Grande, located in the state of Mato Grosso do Sul in the Mid-west region of Brazil, with the aim of investigating the prevalence, risk factors, and genotypes of hepatitis C virus (HCV) infection. A total of 163 patients were interviewed in five dialysis units. Serum samples were screened for anti-HCV. Positive samples were tested for HCV RNA and genotyped. The prevalence of anti-HCV was 11% (95% CI: 6.8-17.1). A history of transfusion with blood that was not screened for anti-HCV and length of time on hemodialysis were associated with HCV infection. HCV RNA was detected in 12 samples: ten were of genotype 1, subtypes 1a (75%) and 1b (8.3%), and two were of genotype 3, subtype 3a (16.7%).

Prevalence and clinical aspects of respiratory syncytial virus A and B groups in children seen at Hospital de Clínicas of Uberlândia, MG, Brazil

Respiratory syncytial virus (RSV) is well recognized as the most important pathogen causing acute respiratory disease in infants and young children, mainly in the form of bronchiolitis and pneumonia. Two major antigenic groups, A and B, have been identified; however, there is disagreement about the severity of the diseases caused by these two types. This study investigated a possible association between RSV groups and severity of disease. Reverse transcription-polymerase chain reaction was used to characterize 128 RSV nasopharyngeal specimens from children less than five years old experiencing acute respiratory disease. A total of 82 of 128 samples (64.1%) could be typed, and, of these, 78% were group A, and 22% were group B. Severity was measured by clinical evaluation associated with demographic factors: for RSV A-infected patients, 53.1% were hospitalized, whereas for RSV B patients, 27.8% were hospitalized (p = 0.07). Around 35.0% of the patients presented risk factors for severity (e.g., prematurity). For those without risk factors, the hospitalization occurred in 47.6% of patients infected with RSV A and in 18.2% infected with RSV B. There was a trend for RSV B infections to be milder than those of RSV A. Even though RSV A-infected patients, including cases without underlying condition and prematurity, were more likely to require hospitalization than those infected by RSV B, the disease severity could not to be attributed to the RSV groups.

Can we measure accurately the prevalence of doping?

Questionnaires are used in the majority of the studies ondoping prevalence in sport. Nevertheless, prevalence is noteasy to evaluate and previous epidemiologic studies demonstrateda wide variance. This variance has mostly beenexplained by sample differences. The way to evaluate dopingprevalence in the survey is questioned in this paper. Aquestionnaire was administered to 1810 amateur athletes(993 males, 817 females). Doping use was ascertained invarious ways, using different definitions of doping and typesof question in the survey. Depending on the definition ofdoping and the type of question used, the prevalence ofdoping obtained can differ enormously, between 1.3 and39.2% of athletes. Marijuana and drugs for asthma were thetwo banned substances most used. The majority of athletesoften ignored the banned list and did not use prohibitedsubstances to dope. Using various ways to question athletes,observing the usage of substances, cross checking the data,taking into account the aim of substances uses and thevarious definitions of doping are necessary to give morereliable prevalence of doping. Moreover, doping at anamateur level seems to be less of a sport problem than asocial problem.