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  • Almeida, Mayron Morais  (2)
  • Carvalho-Costa, Filipe Anibal  (2)
  • 1
    In: Parasites & Vectors, Springer Science and Business Media LLC, Vol. 14, No. 1 ( 2021-12)
    Abstract: 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. Graphical Abstract
    Type of Medium: Online Resource
    ISSN: 1756-3305
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2409480-8
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  • 2
    In: Journal of Tropical Medicine, Hindawi Limited, Vol. 2021 ( 2021-2-4), p. 1-9
    Abstract: 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.
    Type of Medium: Online Resource
    ISSN: 1687-9694 , 1687-9686
    Language: English
    Publisher: Hindawi Limited
    Publication Date: 2021
    detail.hit.zdb_id: 2546526-0
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