Publications by authors named "Genaro O"

A population-based cross-sectional study was set up in Sabará country, Southeastern Brazil, to identify asymptomatic human visceral leishmaniasis in an urban area of low disease prevalence. Blood was collected on filter paper (n=1,604 inhabitants) and examined by indirect immunofluorescent test, enzyme-linked immunosorbent assay and immunochromatographic strip test. The prevalence rates of infection ranged from 2.

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Canine visceral leishmaniasis (CVL) manifests itself as a broad clinical spectrum ranging from asymptomatic infection to patent severe disease. Despite relevant findings suggesting changes on lymphocytes subsets regarding the CVL clinical forms, it still remains to be elucidated whether a distinct phenotypic profile would be correlated with degree of tissue parasite density. Herein, we have assessed the correlation between the clinical status as well as the impact of bone marrow parasite density on the phenotypic profile of peripheral blood leucocytes in 40 Brazilian dogs naturally infected by Leishmania chagasi.

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The skin is the first point of contact with organisms of the genus Leishmania from sand fly vectors, and apparently normal skin of sick dogs harbours amastigote forms of Leishmania chagasi. In relation to canine visceral leishmaniosis (CVL), the ear skin was examined in 10 uninfected dogs (UDs) and in 31 dogs dogs naturally infected with L. chagasi.

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The first choice of treatment for American cutaneous leishmaniasis is the pentavalent antimonial drug. Although it has been shown that this treatment is mostly effective and indicated, some disadvantages should be taken into account such as side effects, long term treatment inconveniences and counter-indication for patients suffering from cardiopathy, nephropathy; yet, aging, pregnancy and other conditions. With the advent of the vaccine anti-American cutaneous leishmaniasis as a prophylactic measure, studies on therapy using the vaccine associated or not with other drugs have been performed by many investigators and it is currently among the alternative treatments and prevention measures for American cutaneous leishmaniasis.

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In order to understand the determinants of human infection by Leishmania chagasi in an urban area, a cross-sectional population based study was conducted using molecular and serologic methods to identify infection. Participants were interviewed using a pre-coded questionnaire. Two criteria were tested to identify risk factors: Model 1--including all participants positive in hybridization by Leishmania donovani complex probe; Model 2--including all participants positive for hybridization and at least one serologic test.

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An evaluation of 5 laboratory methods for diagnosing American cutaneous leishmaniasis (ACL) was carried out on patients from an endemic area of Brazil. From 164 patients presenting cutaneous lesions, and suspected to have ACL, 133 (81.1%) were confirmed for the disease by Montenegro skin test (MST) and/or parasitologic examination (PE).

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We have performed a detailed investigation in 40 dogs naturally infected with Leishmania infantum (syn. chagasi), subdivided into three groups: asymptomatic (AD = 12), oligosymptomatic (OD = 12) and symptomatic (SD = 16), based on their clinical features. Twenty non-infected dogs (CD) were included as control group.

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An evaluation of the microbiota present in cutaneous ulcers from 31 patients with a clinical and parasitological diagnosis of American tegumentary leishmaniasis (ATL) was carried out by the standard filter paper disc technique, including antimicrobial susceptibility of the bacterial isolates. Microbial examination indicated that 21 patients (67.7%) were contaminated with one to four bacteria and some of them also with yeast.

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Control of canine visceral leishmaniasis (VL) remains a difficult and serious problem mostly because there is no reliable and effective vaccine available to prevent this disease. A mixture of three recombinant leishmanial antigens (TSA, LeIF and LmSTI1) encoded by three genes highly conserved in the Leishmania genus have been shown to induce excellent protection against infection in both murine and simian models of cutaneous leishmaniasis. A human clinical trial with these antigens is currently underway.

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The serological diagnosis of canine visceral leishmaniasis (CVL) remains problematic because there areno reliable commercially available tests. Most laboratories use domestically prepared tests such as the enzyme-linked immunosorbent assay (ELISA) or the indirect immunofluorescent antibody test (IFAT). We evaluated rapid immunochromatographic (RICH) test kits for the diagnosis of CVL.

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The performances of ELISA assays with different antigen preparations, such as Leishmania amazonensis or L. chagasi lysates and the recombinant antigens rK-39 and rK-26, were compared using sera or eluates from dried blood collected on filter paper to detect anti-Leishmania antibodies in dogs from a visceral leishmaniasis-endemic area in Brazil. Of 115 IFAT-reactive dogs at 1:40 titre, 106 (92.

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Use of domestic reference values in the flow cytometry analysis is known to improve its accuracy by integrating local variations as gender, race and age. Up to date application of flow cytometry in veterinary medicine has been limited to describe the percentual values just for peripheral lymphocytes subsets of blood. We now report establishment of reference values for a wide range of proportional and absolute numbers of peripheral blood leukocytes, including T cells subsets, B cells, monocytes and eosinophils, applicable to the healthy population of Beagles in Brazil and other regions with similar demographic characteristics.

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The vectorial competence of the tick Rhipicephalus sanguineus is discussed in relation to the epidemiology of canine visceral leishmaniasis, taking into account its strict association with dogs and the low indices of natural infection presented by its known vector, the phlebotomine sand fly Lutzomyia longipalpis. In order to evaluate natural infection by Leishmania chagasi and the infectivity of these parasites in the tick, 39 specimens (6 females, 11 males and 22 nymphs) of R. sanguineus were removed from 21 dogs showing diverse symptoms of zoonotic visceral leishmaniasis (ZVL).

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The effectiveness of flow cytometric assays for canine use is still requiring standardization. Despite several studies using purified mononuclear cells, no methodology or reference ranges are available for immunophenotyping of whole blood leukocytes (WBL). Fresh and pre-fixed WBL were used to identify cell-subsets, (Thy-1(+)/CD5(+)/CD4(+)/CD8(+)/CD21(+) and CD14(+)) and measure MHC-II, CD45RA/CD45RB expression.

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A case-comparison study was carried out to identify risk factors for mucosal manifestations of American cutaneous leishmaniasis (ACL) in southeast Brazil, using a series of 2820 patients, diagnosed with ACL between 1966 and 1999. The significant factors independently associated with mucosal leishmaniasis were: gender, age, nutritional status and length of disease. Mucosal leishmaniasis occurred 1.

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The potential effect of the fucose mannose ligand (FML)-vaccine on immunotherapy of canine visceral leishmaniasis was assayed on five mongrel dogs experimentally infected with Leishmania donovani and on 21 Leishmania chagasi naturally infected dogs when seropositive to FML but completely asymptomatic. The clinical signs of the experimentally infected, symptomatic dogs only disappeared after the complete vaccination. Protection was obtained in 3/5 animals that remained asymptomatic, IDR positive and parasite free, 1 year after infection.

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In the current study we described initial standardization steps of a new methodology to detect anti-live Leishmania (Viannia) braziliensis promastigote antibodies by flow cytometry, followed by analysis of its applicability to clinical studies. We have studied 39 individuals with positive conventional serology to leishmaniasis, classified according to the absence/presence of cutaneous lesions (L- and L+). The results were expressed as percentage of positive fluorescent parasites (PPFP).

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The 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.

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An antigen (LMS) prepared from Leishmania major-like promastigotes was used in an enzyme-linked immunosorbent assay (ELISA) for the diagnosis of human and dog visceral leishmaniasis. The results were compared with those from the indirect immunofluorescent antibody test (IFAT). A total of 1822 canine sera were tested, including sera from dogs with visceral leishmaniasis, transmissible venereal tumors, ehrlichiosis, rickettsiosis, or Chagas' disease and sera from healthy dogs.

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Antigenic extracts from five Leishmania stocks were used to vaccinate C57BL/10 mice. The Leishvacin(R) and PH8 monovalent vaccine yielded the highest IFN-gamma levels in the supernatants of spleen cell culture from vaccinated animals. Each single strain immunized group showed evidence of protective immunity six months after the challenge with promastigotes of Leishmania (Leishmania) amazonensis.

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Background: Leishmaniasis is endemic in 88 countries in the world, and 350 million individuals are at risk of acquiring the disease. Treatment for American cutaneous leishmaniasis (ACL) is long, expensive, and associated with important side-effects.

Methods: In this double-blind, placebo-controlled study, we treated 102 patients with ACL using either a combination of a single-strain Leishmania amazonensis killed promastigote vaccine plus a half dose of meglumine antimoniate, or placebo plus the same half dose regimen of meglumine antimoniate, in 10-day series followed by 10-day intervals.

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The diagnosis value of polymerase chain reaction (PCR) was assessed in patients from an area endemic for American cutaneous leishmaniasis (ACL) in Brazil. Different forms of clinical sample preservation and DNA extraction for PCR were tested. The 4 preservation forms of the skin biopsies from patients suspected to have ACL were as follows: imprinted on filter paper (FP); imprinted on nitrocellulose paper (NP); frozen at -20 degrees C (FB); or immersed in 70% ethanol (EB).

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The most frequent and most important mode of human or canine visceral leishmaniasis (CVL) transmission is through the bite of infected sand flies. This study investigates Leishmania (Leishmania) chagasi vertical transmission in offspring of naturally infected dogs. Thus 63 puppies from 18 female dogs with CVL were used.

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Brazil is the only country endemic for zoonotic visceral leishmaniasis (ZVL) that regularly conducts epidemiologic and prophylactic control programs that involve the treatment of human cases, insect vector control, and the removal of seropositive infected dogs. This report reviews 60 studies reporting data on the efficacy of these recommended control tools and concludes that in Brazil 1) eradication of the disease in Minas Gerais was achieved by the concomitant use of the three control methods, 2) although seropositivity by an immunofluorescent assay is not completely related to infectiousness, the removal of seropositive dogs leads to a significant reduction of canine and human incidence, 3) improvement of the sensitivity of the diagnostic tool used for canine control should optimize the efficacy of control, and 4) although difficult and expensive, the public health dog control campaigns performed in Brazil reduced the incidence of ZVL and should be maintained since treatment of dogs is an unrealistic intervention, both because of its prohibitive cost and relatively poor effectiveness.

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This study was aimed at evaluating the immunogenicity of a vaccine composed of killed Leishmania amazonensis promastigotes using several different protocols in a randomized, double-blind and controlled trial design in order to select one of them for further efficacy trials. One hundred and fourteen leishmanin skin test (LST)-negative healthy volunteers were allocated into eight groups that received either two or three deep intramuscular injections of vaccine at doses of 180, 360 and 540 microg or similar injections of placebo. Cell-mediated immune responses were evaluated before and after vaccination by means of LST as well as proliferative responses and cytokine production in Leishmania antigen-stimulated peripheral blood mononuclear cell cultures.

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