EMED - Escola de Medicina
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/3649
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Item Field randomized trial to evaluate the efficacy of the Leish - Tec vaccine against canine visceral leishmaniasis in anendemic area of Brazil.(2016) Silva, Shara Regina; Feres, Ana Maria Leonardi Tibúrcio; Silva, João Carlos França da; Dias, Edelberto Santos; Michalsky, Érika Monteiro; Andrade, Hélida Monteiro de; Coelho, Eduardo Antônio Ferraz; Ribeiro, Gustavo Meirelles; Fernandes, Ana Paula Salles Moura; Coelho, George Luiz Lins MachadoBackground: A canine vaccine remains a promising approach for effective control of visceral leishmaniasis(VL), given its complex epidemiology in areas where zoonotic VL is prevalent. Leish-Tec®is a recombi-nant vaccine, based on the Leishmania A2 antigen, against canine VL (CVL). It is, since 2014, the singlecommercial vaccine licensed in Brazil. Here, Leish-Tec®efficacy was estimated through a randomizedfield trial (RFT), in a highly VL endemic area.Methods: The RFT was conducted from 2008 to 2010 in an endemic area of southeastern Brazil, presentinga CVL seroprevalence of 41.9%. Eight hundred forty-seven seronegative dogs were randomly selected toreceive Leish-Tec®(n = 429) or placebo (n = 418). Animals were followed up by clinical, serological, andparasitological exams for 18 months. The CVL incidence in both groups was compared through proportionanalysis.Results: A significant reduction in the number of cases of CVL was observed in the vaccine group, ascompared with the placebo group, whether efficacy was estimated according to parasitological results(71.4%; 95% CI: 34.9–87.3%; p = 0.001; risk ratio = 0.287), by adding results of xenodiagnosis and parasito-logical exams (58.1%; 95% CI: 26.0–76.3%; p = 0.002; risk ratio = 0.419). Among the animals that convertedto a positive anti-A2 serology, efficacy reached 80.8% (95% CI: 37.6–94.1%, p = 0.001; risk ratio = 0.192).Xenodiagnosis has detected a reduction of 46.6% (p = 0.05) in transmission to sand flies from vaccinatedanimals presenting anti-A2 positive serology.Conclusion: The Leish-Tec®vaccine proved significantly effective for prophylaxis of CVL, after naturalchallenge assured by transmission of Leishmania parasites, in a highly endemic area. Noteworthy, thisreport has unveiled the complexity of performing a RFT for anti-CVL vaccines in Brazil, which may behelpful for designing of future studies.Item Epidemiological aspects of vector, parasite, and domestic reservoir in areas of recent transmission and no reported human cases of visceral leishmaniasis in Brazil.(2015) Silva, Fabiana de Oliveira Lara; Michalsky, Érika Monteiro; Dias, Consuelo Latorre Fortes; Fiuza, Vanessa de Oliveira Pires; Pessanha, José Eduardo Marques; Silva, Shara Regina; Avelar, Daniel Moreira de; Silva, Maiara Alves; Lima, Ana Cristina Vianna Mariano da Rocha; Costa, Ailton Junior Antunes da; Coelho, George Luiz Lins Machado; Dias, Edelberto SantosAbout 97% of the human cases of the American visceral leishmaniasis (VL) occur in Brazil. In the last fewyears, the disease expanded to medium- and large-sized cities, in which surveillance and control actionshave been intensified, in an effort to control VL spreading. Our two-year study was conducted in BeloHorizonte, the sixth most populous city in Brazil, which is endemic for VL. We focused in two particulardistricts of recent transmission of the disease, with no reported human cases and submitted to minorsurveillance and control actions. Our aim was to draw an epidemiological profile of the local situationconcerning Lutzomyia vector, Leishmania parasites, and the main domestic reservoirs (dogs). Lutzomyialongipalpis comprised 96.5% of the total phlebotomine sand flies captured and displayed an expressiveminimal infection rate by Leishmania infantum (16.7%). Positive correlations were found between the pop-ulation densities of L. longipalpis, rainfall and temperature. L. infantum was also detected in the cortelezziicomplex and, for the first time, in Lutzomyia lloydi. Leishmania braziliensis, an etiological agent of theAmerican cutaneous leishmaniasis, was also identified in L. longipalpis. Among the 1408 dogs serologi-cally tested by standard enzyme-linked and fluorescence immune assays (ELISA/IFA) 3.6% were positivefor VL. L. infantum DNA and Leishmania parasites were identified in 100% and 72.5% of the seropositivedogs, respectively. The co-positivity of other diagnostic tests for VL—Leishmania-nested PCR, imprintand myeloculture—was compared to the standard serology. Both symptomatic or asymptomatic dogsdisplayed an equal average number of positive diagnostic tests for VL. The districts studied display favor-able conditions for the rapid spreading of human infection, in terms of L. longipalpis population density,and presence of L. infantum in both vector and main reservoir.Item Importance of Lutzomyia longipalpis in the dynamics of transmission of canine visceral leishmaniasis in the endemic area of Porteirinha Municipality, Minas Gerais, Brazil.(2005) Silva, João Carlos França da; Barata, Ricardo Andrade; Costa, Roberto Teodoro da; Michalsky, Érika Monteiro; Coelho, George Luiz Lins Machado; Vieira, Edvá P.; Prata, Aluízio; Mayrink, Wilson; Nascimento, Edvaldo; Dias, Consuelo Latorre Fortes; Silva, Jaime C.; Dias, Edelberto SantosA study of Lutzomyia longipalpis (Lutz and Neiva, 1912) (Diptera: Psychodidae), the primary vector of American visceral leishmaniasis (AVL), and the canine form of the disease, was carried out in Porteirinha. The city is situated in the northern part of the Brazilian State of Minas Gerais and is an endemic area of AVL. Systematic phlebotomine captures were performed in seven districts with previously reported cases of canine visceral leishmaniasis, during 2 years (January 2000– December 2001). A total of 2328 specimens of L. longipalpis were captured. The association between the local climate variables and the population density of L. longipalpis was evaluated and rainfall was determined to be a major factor, with increased populations during the rainy season (October–March). At the same time period, blood samples from every dog domiciled in the same seven districts, in total 14,077 animals, were analyzed for infection by viscerotropic Leishmania using indirect immunofluorescence assay (IFA). Accumulated incidence rates of canine VL per district varied from 3.40 to 14.34 for the 2-year period. A positive correlation between the population density of L. longipalpis and the canine cases of visceral leishmaniasis in Porteirinha was observed.Item Leishmaniose visceral : estudo de flebotomíneos e infecção canina em Montes Claros, Minas Gerais.(2005) Michalsky, Érika Monteiro; Silva, João Carlos França da; Costa, Roberto Teodoro da; Costa, Daniela Camargos; Barata, Ricardo Andrade; Paula, Edvá Vieira de; Coelho, George Luiz Lins Machado; Rocha, Marília Fonseca; Dias, Consuelo Latorre Fortes; Dias, Edelberto SantosA leishmaniose visceral no Brasil estava inicialmente associada a áreas rurais, mas devido às diversas alterações no ambiente como, desmatamentos, urbanização e intenso processo migratório, ocorreu a expansão das áreas endêmicas, levando à urbanização da doença, principalmente nas regiões Sudeste e Centro Oeste do país. No município de Montes Claros, situado ao norte de Minas Gerais, foi feito um estudo para verificação da situação da LV. No ano de 2002 foi realizado inquérito sorológico canino e no período de setembro de 2002 a agosto de 2003 foi feito levantamento entomológico, utilizando armadilhas luminosas de CDC. A prevalência da LV canina apresentou taxa média de infecção em torno de 5%. A fauna de flebotomíneos estimada foi de 16 espécies, totalizando 1043 exemplares. Lutzomyia longipalpis foi a espécie predominante com 74%, o que sugere a sua participação na transmissão de LV em Montes Claros.Item Epidemiology of canine visceral leishmaniasis in the endemic area of Montes Claros Municipality, Minas Gerais State, Brazil.(2003) Silva, João Carlos França da; Costa, Roberto Teodoro da; Siqueira, Ari M.; Coelho, George Luiz Lins Machado; Costa, Carlos Alberto da; Mayrink, Wilson; Vieira, Edvá P.; Silva, Jaime Costa daThe Montes Claros City is located in an endemic area for visceral leishmaniosis in the Minas Gerais State, Brazil.With the implementation of a program for the control of visceral leishmaniosis in 1994, a sectional study was carried out to evaluate the infection by viscerotropic Leishmania in the population of dogs from Montes Claros, basically using indirect immunofluorescence antibody test (IFAT). Blood samples were collected on filter paper from 33,937 dogs, representing 96.1% of the canine local population. The prevalence for visceral leishmaniosis was found to be 9.7% in the municipality, being 9.9% in the urban area and 8.8% in the rural area. The annual incidence showed to be 64.3/1000 dogs. Prevalence of infection was not correlated with dogs age. The most affected breeds were: Boxer (24.6%) and Cocker (26.9%); Mongrel dogs had a prevalence of 7.8%. Short-hair animals had a prevalence of 11.9%, while long-furred animals had a prevalence of 8.9%. The isoenzymatic profile indicated that Leishmania (Leishmania) chagasi was the visceral leishmaniosis etiological agent in Montes Claros City, Minas Gerais State, Brazil. The main geographical areas for the parasite transmission were identified, and control measures were immediately started. The role of the dog as a reservoir for L. chagasi was confirmed. It was demonstrated that short-furred animals are at a higher risk of acquiring visceral leishmaniosis than the long-furred dogs.