Browsing by Author "Silva, Thais Almeida Marques da"

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    Effectiveness of the Brazilian Visceral Leishmaniasis Surveillance and Control Programme in reducing the prevalence and incidence of Leishmania infantum infection.
    (2018) Rocha, Iara Caixeta Marques da; Santos, Letícia Helena Marques dos; Vital, Wendel Coura; Cunha, Gisele Macedo Rodrigues da; Magalhães, Fernanda do Carmo; Silva, Thais Almeida Marques da; Morais, Maria Helena Franco; Oliveira, Edward; Reis, Ilka Afonso; Carneiro, Mariângela
    Background Control strategies adopted by the Brazilian Visceral Leishmaniasis Surveillance and Control Programme (VLSCP) include identifying and culling seropositive infected dogs, early diagnosis and treatment of human cases, chemical control of the vector and population awareness. This study evaluated the effectiveness of the VLSCP on the prevalence and incidence rates of Leishmania infantum in children residing in areas under different VLSCP intervention times. Methods A quasi-experimental epidemiological study with a panel (two cross-sectional) and a concurrent cohort was performed in three areas of Belo Horizonte, southeast Brazil. The first cross-sectional study (I) was carried out with 1875 children, 478 of which were enrolled in the cohort study. In the second cross-sectional study (II), 413 additional children were included, totalizing 891 children. Laboratory diagnosis was performed by ELISA-rK39. Analyses included multilevel logistic and Poisson regression models. Results The incidence rates of L. infantum infection were: 14.4% in the area where VLSCP intervention was initiated in 2006 (AI2006); 21.1% in the area where intervention was initiated in 2008 (AI2008); and 11.6% in the area where intervention was initiated in 2010 (AI2010 - control area). A follow-up period of 24 months showed that the persons-time incidence rates in AI2006, AI2008, and AI2010 were: 6.2/100, 10/100, and 5.6/100 persons/24 months, respectively. The final prevalence rates of infection (cross-sectional II - in 2012), compared to the initial rates (cross-sectional I - in 2010), increased 83.7% in AI2006, 74.1% in AI2008, and decreased 5% in AI2010. Analysis of the effectiveness revealed that children residing in AI2008 are more likely to be infected (OR = 1.84; 95% CI: 1.06-3.23) and present a higher risk of infection (IRR = 1.76; 95% CI: 1.05-2.95) compared to those in AI2010. No statistically significant differences were observed in asymptomatic infection (OR and IRR) in AI2006 compared to AI2010. Conclusions The VLSCP was not effective at controlling L. infantum infection in areas where interventions had respectively been carried out for six and four years. However, it is unclear what the consequences in terms of human infection and diseases would be in the absence of the VLSCP. Efforts to improve the effectiveness of control measures remain a necessary priority.
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    Genetic homogeneity among Leishmania (Leishmania) infantum isolates from dog and human samples in Belo Horizonte Metropolitan Area (BHMA), Minas Gerais, Brazil.
    (2015) Silva, Thais Almeida Marques da; Gomes, Luciana Inácia; Oliveira, Edward; Vital, Wendel Coura; Silva, Letícia de Azevedo; Pais, Fabiano Sviatopolk Mirsky; Ker, Henrique Gama; Reis, Alexandre Barbosa; Rabello, Ana Lúcia Teles; Carneiro, Mariângela
    Background: Certain municipalities in the Belo Horizonte Metropolitan Area (BHMA), Minas Gerais, Brazil, have the highest human visceral leishmaniasis (VL) mortality rates in the country and also demonstrate high canine seropositivity. In Brazil, the etiologic agent of VL is Leishmania (Leishmania) infantum. The aim of this study was to evaluate the intraspecific genetic variability of parasites from humans and from dogs with different clinical forms of VL in five municipalities of BHMA using PCR-RFLP and two target genes: kinetoplast DNA (kDNA) and gp63. Methods: In total, 45 samples of DNA extracted from clinical samples (n = 35) or L. infantum culture (n = 10) were evaluated. These samples originated from three groups: adults (with or without Leishmania/HIV co-infection; n = 14), children (n = 18) and dogs (n = 13). The samples were amplified for the kDNA target using the MC1 and MC2 primers (447 bp), while the Sg1 and Sg2 (1330 bp) primers were used for the gp63 glycoprotein target gene. Results: The restriction enzyme patterns of all the samples tested were monomorphic. Conclusions: These findings reveal a high degree of genetic homogeneity for the evaluated gene targets among L. infantum samples isolated from different hosts and representing different clinical forms of VL in the municipalities of BHMA studied.
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    Spatial and temporal trends of visceral leishmaniasis by mesoregion in a southeastern state of Brazil, 2002-2013.
    (2017) Silva, Thais Almeida Marques da; Vital, Wendel Coura; Barbosa, David Soeiro; Oiko, Carla Sayuri Fogaça; Morais, Maria Helena Franco; Tourinho, Bruna Dias; Melo, Diogo Portella Ornelas de; Reis, Ilka Afonso; Carneiro, Mariângela
    This article presents the spatial and temporal distribution of visceral leishmaniasis (VL) in Minas Gerais State and identifies the greater risk areas of transmission. This study is both timely and substantive because Minas Gerais is an important Brazilian state in the number of cases of visceral leishmaniasis. The results showed that during the 12-year time series the VL had a heterogeneous spatial and temporal distribution in the state of Minas Gerais. Among the 12 existing mesoregions, six (Central Mineira, Jequitinhonha, Metropolitan area of Belo Horizonte, Northwest of Minas, North of Minas, and Vale do Rio Doce) were responsible for the expansion and maintenance of VL in the state. Among them, the Vale do Rio Doce and Jequitinhonha mesoregions presented a considerable increase in the incidence rates of the disease in the last period. In the other six mesoregions only sporadic cases of the disease were reported during the study period. The results of in this study may contribute to a better understanding the dynamic of the disease in Minas Gerais. Also these findings can provide subsidies to assist the actions of the control program of VL.