Time filter

Source Type

Thies S.F.,Federal University of Mato Grosso | Ribeiro A.L.M.,Federal University of Mato Grosso | Miyazaki R.D.,Federal University of Mato Grosso | Fortes-Dias C.L.,Diretoria de Pesquisa e Desenvolvimento | Fontes C.J.F.,Federal University of Mato Grosso
Revista da Sociedade Brasileira de Medicina Tropical | Year: 2013

Introduction: American cutaneous leishmaniasis (ACL) has been reported in every municipality of the State of Mato Grosso, Brazil, but the transmission epidemiology remains poorly understood. Our study was developed in a rural area of the Nova Mutum municipality where four autochthonous cases of ACL were reported in 2009. Our aims were to describe the local phlebotomine sandfly fauna and to investigate the infection rates and infecting Leishmania species in the captured sandflies. Methods: Entomological captures were performed bimonthly at 10 fixed sites close to the edge of a forested area between June 2011 and April 2012. Results: A total of 3,743 phlebotomine sandflies belonging to 31 distinct species were captured. Approximately 75% of the specimens were females. The most abundant species (45.4%) was Lutzomyia antunesi, which was consistently captured at every site. Species that are epidemiologically important for ACL, such as L. flaviscutellata, L. whitmani and L. umbratilis, were also captured. L. antunesi and L. ubiquitalis were naturally infected by Leishmania braziliensis or Le. guyanensis, with minimum infection rates of 0.88% and 6.67%, respectively. Surprisingly, L. antunesi was infected by Le. infantum (synonym chagasi). Conclusions: The natural infection of L. antunesi and L. ubiquitalis by Leishmania sp. suggests that these species might play a role in the zoonotic cycle of ACL in Nova Mutum. The presence of Le. infantum in L. antunesi suggests that there may be a risk of an outbreak of visceral leishmaniasis (VL) in Nova Mutum. Source

Fortes-Dias C.L.,Diretoria de Pesquisa e Desenvolvimento | Fiuza V.O.P.,Secretaria Municipal de Saude de Belo Horizonte | Pessanha J.E.M.,Secretaria Municipal de Saude de Belo Horizonte | Machado-Coelho G.L.L.,Federal University of Ouro Preto
Acta Tropica | Year: 2015

About 97% of the human cases of the American visceral leishmaniasis (VL) occur in Brazil. In the last few years, the disease expanded to medium- and large-sized cities, in which surveillance and control actions have been intensified, in an effort to control VL spreading. Our two-year study was conducted in Belo Horizonte, the sixth most populous city in Brazil, which is endemic for VL. We focused in two particular districts of recent transmission of the disease, with no reported human cases and submitted to minor surveillance and control actions. Our aim was to draw an epidemiological profile of the local situation concerning Lutzomyia vector, Leishmania parasites, and the main domestic reservoirs (dogs). Lutzomyia longipalpis comprised 96.5% of the total phlebotomine sand flies captured and displayed an expressive minimal infection rate by Leishmania infantum (16.7%). Positive correlations were found between the population densities of L. longipalpis, rainfall and temperature. L. infantum was also detected in the cortelezzii complex and, for the first time, in Lutzomyia lloydi. Leishmania braziliensis, an etiological agent of the American cutaneous leishmaniasis, was also identified in L. longipalpis. Among the 1408 dogs serologically tested by standard enzyme-linked and fluorescence immune assays (ELISA/IFA) 3.6% were positive for VL. L. infantum DNA and Leishmania parasites were identified in 100% and 72.5% of the seropositive dogs, respectively. The co-positivity of other diagnostic tests for VL- Leishmania-nested PCR, imprint and myeloculture-was compared to the standard serology. Both symptomatic or asymptomatic dogs displayed an equal average number of positive diagnostic tests for VL. The districts studied display favorable 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. © 2015 Elsevier B.V. Source

Silva L.M.,Diretoria de Pesquisa e Desenvolvimento | Fortes-Dias C.L.,Diretoria de Pesquisa e Desenvolvimento
Micron | Year: 2014

The etiological agent of schistosomiasis in Brazil, Schistosoma mansoni, requires an obligatory passage through Biomphalaria snails to complete its life cycle. In these intermediate hosts, interaction with the parasite is mediated by humoral factors and hemocytes by mechanisms that are not yet fully understood. Extant studies exploring these processes are usually conducted through experimental infection of Biomphalaria with S. mansoni miracidia. Thus, tissue-derived cultures of Biomphalaria may be useful in increasing the understanding of that interaction at cellular level. However, in the absence of morphological characterization of those cells in culture, the application of such models is delayed. In the present work, we cultured different tissues of B. tenagophila, the second most important host of S. mansoni in Brazil, using a strain that is naturally and absolutely resistant to S. mansoni infection. This decision was driven by the view that this strain might be provided with the most effective response against parasite infection. Primary cultures were successfully established from nine Biomphalaria tissues and the respective cells in culture were ultra structurally described. Attention was particularly devoted to cells derived from mantle cavity and kidney tissues. Although they have been considered important centers for hemocyte production in Biomphalaria, no detailed cell characterization is available in the pertinent literature. Herein, kidney-derived cells partially shared hematoblast characteristics. Moreover, under optical microscopy, kidney cells in culture were very similar to those derived from amebocyte-producing organ (APO) cultures, which have been recently shown to be capable of eliminating S. mansoni sporocysts in vitro. Based on the close resemblance of those cultures and their anatomical proximity inside the mantle cavity, we suggest the effective participation of Biomphalaria kidney cells in hematopoiesis and in host response to S. mansoni infection. © 2014 Elsevier Ltd. Source

Introduction: Visceral leishmaniasis has been notified in nearly all states of Brazil, and particularly in the north of Minas Gerais, where the disease is endemic. The aim of this study was to detect natural infection of Lutzomyia longipalpis and, through the PCR/RFLP technique, identify Leishmania species found in sandflies in the municipality of Janaúba. Methods: Using light traps, 1,550 females of L. longipalpis were caught and grouped into pools of 10 specimens to be subjected to DNA extraction and amplification, by means of generic PCR and cacophony. Results: Out of the 155 pools, six were positive for Leishmania sp., and thus the infection rate in the municipality was 3.9%. Trough PCR/RFLP, the digestion pattern among the positive samples was found to be similar to that of the reference strain of Leishmania chagasi (MHOM/BR/74/PP75). Conclusions: Te detection of natural infection associated with studies on the epidemiology of visceral leishmaniasis suggests that L. longipalpis is involved in transmission of L. infantum chagasi in Janaúba, particularly in areas of intense transmission of visceral leishmaniasis. Source

Santos-Filho N.A.,University of Sao Paulo | Fernandes C.A.H.,Sao Paulo State University | Menaldo D.L.,University of Sao Paulo | Magro A.J.,Sao Paulo State University | And 4 more authors.
Biochimie | Year: 2011

Phospholipases A2 (PLA2s) are important components of Bothrops snake venoms, that can induce several effects on envenomations such as myotoxicity, inhibition or induction of platelet aggregation and edema. It is known that venomous and non-venomous snakes present PLA2 inhibitory proteins (PLIs) in their blood plasma. An inhibitory protein that neutralizes the enzymatic and toxic activities of several PLA2s from Bothrops venoms was isolated from Bothrops alternatus snake plasma by affinity chromatography using the immobilized myotoxin BthTX-I on CNBr-activated Sepharose. Biochemical characterization of this inhibitory protein, denominated αBaltMIP, showed it to be a glycoprotein with Mr of ∼24,000 for the monomeric subunit. CD spectra of the PLA2/inhibitor complexes are considerably different from those corresponding to the individual proteins and data deconvolution suggests that the complexes had a relative gain of helical structure elements in comparison to the individual protomers, which may indicate a more compact structure upon complexation. Theoretical and experimental structural studies performed in order to obtain insights into the structural features of αBaltMIP indicated that this molecule may potentially trimerize in solution, thus strengthening the hypothesis previously raised by other authors about snake PLIs oligomerization. © 2010 Elsevier Masson SAS. All rights reserved. Source

Discover hidden collaborations