Epidemiology, species composition and genetic diversity of tetra- and octonucleated Entamoeba spp. in different Brazilian biomes.

BACKGROUND: Entamoeba species harbored by humans have different degrees of pathogenicity. The present study explores the intra- and interspecific diversity, phylogenetic relationships, prevalence and distribution of tetra- and octonucleated cyst-producing Entamoeba in different Brazilian regions. METHODS: Cross-sectional studies were performed to collect fecal samples (n = 1728) and sociodemographic data in communities located in four Brazilian biomes: Atlantic Forest, Caatinga, Cerrado, and Amazon. Fecal samples were subjected to molecular analysis by partial small subunit ribosomal DNA sequencing (SSU rDNA) and phylogenetic analysis. RESULTS: Light microscopy analysis revealed that tetranucleated cysts were found in all the studied biomes. The highest positivity rates were observed in the age group 6-10 years (23.21%). For octonucleated cysts, positivity rates ranged from 1 to 55.1%. Sixty SSU rDNA Entamoeba sequences were obtained, and four different species were identified: the octonucleated E. coli, and the tetranucleated E. histolytica, E. dispar, and E. hartmanni. Novel haplotypes (n = 32) were characterized; however, new ribosomal lineages were not identified. The Entamoeba coli ST1 subtype predominated in Atlantic Forest and Caatinga, and the ST2 subtype was predominant in the Amazon biome. E. histolytica was detected only in the Amazon biome. In phylogenetic trees, sequences were grouped in two groups, the first containing uni- and tetranucleated and the second containing uni- and octonucleated cyst-producing Entamoeba species. Molecular diversity indexes revealed a high interspecific diversity for tetra- and octonucleated Entamoeba spp. (H ± SD = 0.9625 ± 0.0126). The intraspecific diversity varied according to species or subtype: E. dispar and E. histolytica showed lower diversity than E. coli subtypes ST1 and ST2 and E. hartmanni. CONCLUSIONS: Tetra- and octonucleated cyst-producing Entamoeba are endemic in the studied communities; E. histolytica was found in a low proportion and only in the Amazon biome. With regard to E. coli, subtype ST2 was predominant in the Amazon biome. The molecular epidemiology of Entamoeba spp. is a field to be further explored and provides information with important implications for public health.

Socioenvironmental Factors Influencing Distribution and Intensity of Soil-Transmitted Helminthiasis in the Brazilian Amazon: Challenges for the 2030 Agenda.

Soil-transmitted helminthiasis (STHs) are poverty-related diseases with high prevalence rates in developing countries. The present study aims to describe the epidemiological scenario of STHs in an urban population in the Brazilian Amazon. A cross-sectional survey (n = 349 children aged 1-15 years) was carried out to obtain faecal samples and sociodemographic and sanitation data. Among the children, 143 (41%) were positive for at least one STH. Prevalence rates of infections by A. lumbricoides, T. trichiura, and hookworms were 24.4%, 42.6%, and 9%, respectively. A logistic regression multivariate model showed that infection with A. lumbricoides is significantly more frequent in children aged 11-15 years (odds ratio [OR] = 2.38; 95% confidence interval [CI] = 1.15-4.94; p=0.018) and the presence of latrines inside houses is a protection factor against ascariasis (OR = 0.38; 95% CI = 0.17-0.85; p=0.019). Positivity for T. trichiura is higher in the 5-10 (OR = 3.31; 95% IC = 1.85-5.89; p=0.001) and 11-15 age groups (OR = 3.16; 95% IC = 1.66-6.00; p=0.001), in children living in poor families (OR = 1.78; 95% IC = 1.01-3.14; p=0.045) and practicing open evacuation (OR = 2.07; 95% IC = 1.07-3.99; p=0.029). Hookworm infection is more frequent in children aged 11-15 years (OR = 6.70; 95% IC = 1.91-23.43; p=0.002), males (OR = 6.35; 95% IC = 2.00-20.14; p=0.002), and those living in stilt houses (OR = 3.52; 95% IC = 1.22-10.12; p=0.019). The use of albendazole in the last six months was a protection factor against hookworm infection (OR = 0.31; 95% IC = 0.10-0.96; p=0.042). The proportion of mild, moderate, and severe infections was 55.2%, 37.8%, and 7%, respectively, for A. lumbricoides, 72.4%, 24.3%, and 3.3% for T. trichiura, and 93.8%, 3.1%, and 3.1% for hookworms. Significantly higher worm burdens in T. trichiura and hookworm infections were associated with practicing open defecation and living in stilt houses. The data points to the need to improve sanitation infrastructure in Amazonian cities with similar sociodemographic and environmental characteristics.

Nível dos Conhecimentos Sobre as Leishmanioses Visceral e Tegumentar pela População de Alguns Bairros de Teresina, Piauí, Brasil / Level of Knowledge of Visceral and Cutaneous Leishmaniasis by the Population from some districts of Teresina, Piauí, Brazil

As leishmanioses são antropozoonoses de ampla distribuição mundial e consideradas um grave problema de saúde pública. Com base nasinformações sobre os aspectos epidemiológicos, a população pode mudar seu comportamento e atitude diante de tais doenças e, assim, tomarmedidas preventivas que possam minimizar os riscos de contraí-las. Esse estudo teve como objetivo identificar o nível de conhecimentoda população de Teresina, Piauí, sobre Leishmaniose Visceral (LV) e Leishmaniose Tegumentar Americana (LTA). A coleta dos dados foirealizada por meio de questionário em 150 residências nos bairros Santo Antônio, Pedra Mole e Parque Alvorada no período de fevereiroa junho de 2013. A análise dos dados mostrou que grande maioria dos casos de leishmaniose ocorreu em indivíduos que possuíam nomáximo o ensino fundamental completo e a renda familiar, na maioria dos entrevistados, chegou a um salário mínimo. Além disso, 89,3%das residências possuíam acumulo de matéria orgânica no peridomicílio, e todas estavam localizadas próximas de matas; 78,6% citarama presença de mosquitos e de animais domésticos. 94,6% dos entrevistados desconheciam tanto a LTA, como também o transmissor dadoença. Tal fato corrobora que a população desconhece que a presença de vegetação no peridomicílio, acúmulo de matéria orgânica,presença de animais domésticos, dentre outros fatores contribuem para a proliferação do vetor e para o estabelecimento e disseminação dasleishmanioses no meio urbano.

Leishmaniases are anthropozoonoses with broad worldwide distribution, being considered a serious public health issue. Based onepidemiological aspects, the population behavior can change towards such diseases, by adopting preventive measures to minimize thecontagion risks. The present study aimed to verify the knowledge level of the population from Teresina, Piauí (Brazil) about visceralleishmaniasis (VL) and American cutaneous leishmaniasis (ATL). Data collection was accomplished through application of a questionnaireto 150 domiciles in the districts of Santo Antônio, Pedra Mole and Parque Alvorada, from February to June 2013, regarding ecoepidemiologicalaspects of these diseases. Analysis of the data revealed that the majority of leishmaniasis cases affected individuals withminima education, with household income of one minimum wage. In addition, 89.3% of the domiciles presented accumulation of organicmatter in the household surroundings, and all were located close to forests; 78.6% cited the presence of mosquitos, and 79.3% the existenceof domestic animals. Among the surveyed, most knew neither ATL nor the disease?s carrier. This fact corroborates that the populationignores the presence of vegetation in the domicile surroundings, accumulation of organic matter, presence of domestic animals, amongother factors, as contributing elements for proliferation of the vector and establishment and dissemination of leishmaniases in the urbanenvironment.