Aloísio Falqueto

Effect of Eliminating Seropositive Canines on the Transmission of Visceral Leishmaniasis in Brazil

In Brazil, where Leishmania chagasi causes endemic American visceral leishmaniasis (AVL), the spread and maintenance of human disease are attributed to canine reservoirs. However, despite measures directed toward the elimination of infected canines, the incidence of human disease continues to increase. To evaluate the role of infected canines in the acquisition of AVL by humans, we undertook a controlled intervention study in three similar, but isolated, valleys of Pancas, Espírito Santo, Brazil. In the two experimental (intervention) valleys, infected dogs were eliminated whereas in the control valley, seropositive canines remained untouched. During the 12-month study period, human seropositivity rates, as measured by dot enzyme-linked immunosorbent assay, increased from 15% to 54% in the intervention valleys and from 14% to 54% in the control valley. The elimination of infected canines in the intervention valleys did not result in a statistically significant difference between the incidences of human serological conversion in the intervention and control valleys at either 6 (20% and 22%, respectively; P = .5961) or 12 months (26% and 27%, respectively; P = .9442). The role of humans as a significant reservoir for AVL is proposed as an explanation for the study results.

Genetic Polymorphism and Molecular Epidemiology of Leishmania (Viannia) braziliensis from Different Hosts and Geographic Areas in Brazil

ABSTRACT Numerical zymotaxonomy and variability of the internal transcribed spacers (ITS) between the small and large subunits of the rRNA genes were used to examine strain variation and relationships in natural populations of Leishmania (Viannia) braziliensis. A total of 101 strains from distinct hosts and Brazilian geographic regions were assigned to 15 zymodemes clustered in two major genetic groups. The great number of isolates (48.5%) placed in zymodeme IOC/Z-27 were collected on the Atlantic coast. The high molecular diversity found in populations in the Amazon Basin was related to the great number of sandfly vector(s) in that region. The results of the restriction fragment length polymorphism analysis of the ITS depicted considerable intraspecific variation. Genotypic groups A, B, and C contained 39, 40, and 22 isolates, which were divided into 16, 10, and 15 genotypes, respectively. The genetic polymorphism observed demonstrates the degree of diversity of L. (V.) braziliensis strains from different regions where they are endemic. The results reinforce the clonal theory for Leishmania parasites showing the genetic diversity of this pathogen and an association of L. (V.) braziliensis genotypes with specific transmission cycles, probably reflecting an adaptation of different clones to the vector species involved.

Comparative Evaluation of Enzyme-Linked Immunosorbent Assays Based on Crude and Recombinant Leishmanial Antigens for Serodiagnosis of Symptomatic and Asymptomatic Leishmania infantum Visceral Infections in Dogs

ABSTRACT The diagnosis of visceral leishmaniasis remains difficult in rural areas where the disease is endemic, and serologic methods still need assessment, as they are not very sensitive for the detection of asymptomatic infectious dogs. Here we present data on the development of enzyme-linked immunosorbent assay (ELISA)-based methods for the detection of antibodies against recombinant leishmanial antigens (namely, the recombinant K26 [rK26] and rK39 antigens from Leishmania infantum and the rA2 protein from Leishmania donovani) in comparison to ELISAs employing crude soluble antigen (CSA). The assays utilized sera from known negative controls (n = 25) and clinically asymptomatic (n = 50) and symptomatic (n = 50) dogs with confirmed L. infantum infections. Additional studies were also done using sera from animals harboring other infections (n = 14) for the evaluation of cross-reactivity. Our study indicated that rK26 and rK39 used in ELISAs provided very high sensitivities for the detection of symptomatic dogs (94% and 100%, respectively), followed by CSA (88%) and rA2 (70%). Conversely, rA2 was more sensitive for asymptomatic dogs (88%) than rK39 and rK26 (both 66%) and CSA (30%). Some cross-reactivity in sera from dogs with other infections (Leishmania braziliensis and Leptospira interrogans) was identified, but the rA2 protein provided the greatest specificity (98%). Data further indicate that all three recombinant proteins must be used in parallel to detect essentially all infected dogs. Efforts should be made to develop a cheap and reliable serologic test based on epitope selection from these diagnostic markers for the sensitive detection of L. infantum-infected dogs.

Evaluation of a novel chromatographic immunoassay based on Dual-Path Platform technology (DPP® CVL rapid test) for the serodiagnosis of canine visceral leishmaniasis.

Canine visceral leishmaniasis (CVL) is the major source of human visceral leishmaniasis (VL) and is transmitted from dogs to sand flies to humans. To control the spread of this disease, early and accurate detection of infected dogs is critical but challenging. Here we demonstrate the potential of the Dual-Path Platform (DPP(®)) CVL rapid test for detecting K26/K39-reactive antibodies in sera from clinically symptomatic (n=60) and asymptomatic (n=60) Leishmania infantum-infected dogs. For the specificity evaluation, assays were performed using known negative diagnostic serum samples (n=59) and cross-reaction control sera (n=11) from animals born in a VL-free area of Brazil. The diagnostic kit displayed high specificity (96%) but low sensitivity (47%) in identifying parasite-positive dogs without signs of CVL. However, the test sensitivity was significantly higher (98%) in diseased cases, indicating that this convenient test may be useful to identify the most infectious dogs. Efforts should be pursued to obtain a more sensitive DPP-multiplexed test parameter (i.e. based on simultaneous yet separate antibody detection of carefully selected multiple antigens of diagnostic utility) for effective serodiagnosis of early-infected dogs, as this will likely allow more efficient canine removal regimens than those used in practice by public health services.

Participação do cão no ciclo de transmissão da Leishmaniose tegumentar no município de Viana, Estado do Espírito Santo, Brasil

In an endemic area of cutaneous leishmaniasis in the viana municipality, Espirito Santo state, an investigation was performed on natural hosts of leishmania among domestic animals, trying to correlate the presence of infected animals with the occurrence of the disease in humans. Within a three weeks period 186 dogs were examined and 32 (17,2%) were found infected.Eleven new cases of cutaneous leishmaniasis were recorded during one year, among people living in the endemic area. A close relationship was between the presence of infected dogs and the occurrence of human leishmaniasis. In the area studied, the disease seems to behave as a zoonosis maintained by domestic dogs.

Associação entre tabagismo e paracoccidioidomicose: um estudo de caso-controle no Estado do Espírito Santo, Brasil

A paracoccidioidomicose e a principal micose sistemica em nosso meio, que exige tratamento prolongado, de alto custo, e que deixa sequelas graves nos pulmoes, orgaos mais frequentemente acometidos e sujeitos ainda as agressoes de fatores de risco externos, como o tabaco. Investigou-se, por meio de um estudo caso-controle, a influencia do tabagismo e do alcoolismo no desenvolvimento da forma cronica da paracoccidioidomicose. Dados sobre a ocupacao, moradia e habitos de vida foram obtidos de 70 doentes e 180 controles. Os doentes fumavam e bebiam mais que os controles. A chance de adoecer foi 14 vezes maior entre os fumantes e 3,6 vezes maior entre os que bebiam acima de 50g/dia de alcool. Na regressao logistica, foram significativas as variaveis consumo de tabaco por mais de 20 anos (OR = 10,1), consumo de cigarros industrializados (OR = 4,8) e consumo de alcool acima de 50g/dia (OR = 2,9). Os doentes que fumavam 20 ou mais cigarros/dia adoeceram em media oito anos antes que os demais (p = 0,002). O consumo de alcool acima de 50g/dia nao influenciou na idade de adoecimento (p = 0,78). Conclui-se que o tabagismo constitui fator de risco para o desenvolvimento da paracoccidioidomicose; o alcoolismo atuaria como um co-fator, associado ao tabagismo.

Distribution of sand flies (Diptera: Psychodidae) at different altitudes in an endemic region of American cutaneous leishmaniasis in the State of Espírito Santo, Brazil

The involvement of different sand fly species in the transmission of American cutaneous leishmaniasis (ACL) at different altitudes was evaluated in the municipality of Afonso Cláudio in the State of Espírito Santo, Brazil, from November 1995 to February 1997. CDC light traps and Shannon traps baited with human volunteers were hung simultaneously at three altitudes of a river valley: (a) 650-750 m in an area of active ACL transmission; (b) 750-850 m in a transitional area; and (c) 850-950 m in an area where no ACL transmission occurred. A total of 13,363 specimens belonging to 28 species was collected. The five most abundant man-biting species were Lutzomyia intermedia, which constituted 24.3% of the total, Lu. migonei (22.3%), Lu. whitmani (15.4%), Lu. fischeri (14.9%) and Lu. monticola (5.8%). Analysis of the distribution of these species at the three altitudes provided evidence that Lu. fischeri and Lu. monticola were not involved in ACL transmission, whereas Lu. migonei and Lu. whitmani might act as secondary vectors of Leishmania (Viannia) braziliensis and Lu. intermedia was probably the principal vector of the parasite. These results reinforce those published in the existing literature, which indicate that Lu. intermedia is the main vector of Le. (V.) braziliensis in Southeast Brazil, while Lu. migonei and Lu. whitmani are of secondary importance.

Effect of deltamethrin spraying on the sandfly populations in a focus of American cutaneous leismaniasis

The effect of deltamethrin of the sandfly population in a focus of American Cutaneous Leishmaniasis in Viana, Espírito Santo State is described. The phlebotomine population density was determined inside and outside houses during a one year period in a treated and untreated area. The results showed a significant reduction in the number of sandflies inside houses in the treated area compared with both the untreated area and the same area before spraying. Despite having a residual action for 12 months after spraying the insecticide was ineffective outside houses. It is concluded therefore that deltamethrin is an efficient insecticide for reducing the number of phlebotomine sandflies inside houses.

Avaliação comparativa da eficácia e toxicidade do antimoniato de N-metil-glucamina e do Estibogluconato de Sódio BP88® no tratamento da leishmaniose cutânea localizada

This randomized, single blind clinical trial was performed to compare the efficacy and toxicity of BP88 Sodium Stibogluconate (SS) to Glucantime® (N-methyl-glucamine), (GL). Sixty-three patients were randomly assigned to one of two groups: 32 patients were treated with GL and 3l patients were treated with SS. Both groups received 15mg Sb+5/kg/day for 20 days. Toxicity was evaluated through EKG, urea, creatinine, AST, ALT, alkaline phosphatase, amylase, and lipase, assessed before treatment, on day 10 and day 20 of treatment and 90 days after treatment. In the group treated with GL, 81% (26/32) of patients were cured compared to 77% (24/31) in the SS group. Five (16%) patients relapsed in the GL group compared to 6 (19%) in the SS group. One patient in each group did not respond to treatment. AST, ALT, amylase, and lipase were more elevated in the SS group (p < 0.05). In conclusion, the efficacy of both treatments was similar although there was more toxicity in the ES group.Foi realizado ensaio clinico randomizado simples cego para comparar a eficacia e a toxicidade do estibogluconato de Na+ (ES) e o antimoniato de N-metil glucamina, o Glucantime®(GL). Sessenta e tres pacientes foram distribuidos em um dos dois grupos: 32 pacientes foram tratados com GL e 31 pacientes com o ES. Ambos os grupos receberam 15mg Sb+5/kg/dia durante 20 dias. A toxicidade foi avaliada atraves do ECG, dosagens de ureia, creatinina, TGO, TGP, fosfatase alcalina, amilase, e lipase, avaliados antes do tratamento, nos dias 10 e 20 do tratamento, e 90 dias apos o termino do mesmo. No grupo tratado com GL 81% (26/32) dos pacientes curaram, comparados com 77% (24/31) no grupo do ES. Um paciente em cada grupo nao respondeu ao tratamento. TGO, TGP, amilase, e lipase foram mais elevadas no grupo que usou o ES (p < 0,05). Concluiu-se que, a eficacia de ambos os tratamentos foram similares, apesar da maior toxicidade observada no grupo tratado com ES.

Epidemiological and clinical features of Leishmania (Viannia) braziliensis American cutaneous and mucocutaneous leishmaniasis in the State of Espírito Santo, Brazil

Between 1985 and 2000, epidemiological surveys of the American tegumentary leishmaniasis (ATL) were carried out in several rural and urban communities in Espírito Santo, Brazil. A total of 100 stocks of Leishmania (comprising isolates from both human and canine hosts with ATL) were identified by two methods of molecular characterization, using specific monoclonal antibodies and multilocus enzyme electrophoresis. Parasite isolates from 19 municipalities were found to belong to the same zymodeme and serodeme type as of the Leishmania (Viannia) braziliensis reference strain. In contrast, our genotyping studies have shown intra-specific variation among these parasites (comparisons of the variability of the internal transcribed spacers between the small and large subunits of the rRNA genes of the 22 stocks studied revealed at least 11 genotypes). Two main clusters of L. (V.) braziliensis genotypes were observed, representing parasites collected from different endemic regions in the state, where transmission reflects distinct eco-epidemiological features. Infection with this pathogen was associated with the characteristic disease forms, but neither the clinical outcome nor the response to treatment could be related to the genetic polymorphism of the isolates, as defined by using the proposed methodology.