Distinct ultrastructural aspects in different biopsies of a single patient with diffuse cutaneous leishmaniasis

The authors investigated the relation between parasites and host-cells in active and regressed lesions of a patient with diffuse cutaneous leishmaniasis, evaluating the frequency of different cell types, and the location and integrity of amastigotes. No correlation was found between parasite integrity and size of parasitophorous vacuoles. They observed ultrastructural findings characterizing a cell mediated immune response: macrophages lysis, parasitic destruction inside macrophages, close contact between parasitized macrophages and lymphocytes and between parasites and lymphocytes, lymphocytic infiltration and fibrosis. They suggest that in DCL there is a limited cellular immune response, although insufficient to control infection.

Prevalence and levels of IgG and IgM antibodies against Plasmodium falciparum and P. vivax in blood donors from Rondônia, Brazilian Amazon

Antibodies of IgG and IgM isotopes reacting with Plasmodium falciparum and P. vivax thick-smear antigens were searched for by the indirect fluorescent antibody test (IFAT) in a random sample of 230 blood donors at the transfusion centre of Porto Velho (HEMERON), Rondônia State, western Brazilian Amazon. A high prevalence of IgG seropositivity (32% against P. falciparum, 24% against P. vivax and 37% against either P. falciparum or P. vivax antigens) was detected among them, despite the fact that candidates reporting recent (<12 months) malaria attacks were not elegible. Only a small proportion of them had also detectable IgM antibodies to these antigens. These data suggest an intense, relatively recent exposure to malaria in such an urban population sample. However, parasitaemia (as detected by microscopical examination of Giemsa-stained thick smears) was patent in only one prospective donor. The antibody profile of blood donors was compared with that of healthy subjects of all age groups, living in a close endemic area (Candeias village, 21 km east of Porto Velho). The villagers were classified into two groups according to their history of a recent (<12 months) or a remote (>12 months) past malaria attack due to either P. falciparum or P. vivax. Extensive overlapping was observed when the distribution of antibody titres of healthy subjects from Candeias village with a recent and remote malaria history was compared. In conclusion, subjects with a recent or a remote malaria history could not be distinguished by sorological criteria alone.

Developing new approaches for detecting and preventing Aedes aegypti population outbreaks: basis for surveillance, alert and control system

A new approach to dengue vector surveillance based on permanent egg-collection using a modified ovitrap and Bacillus thuringiensis israelensis(Bti) was evaluated in different urban landscapes in Recife, Northeast Brazil. From April 2004 to April 2005, 13 egg-collection cycles of four weeks were carried out. Geo-referenced ovitraps containing grass infusion, Bti and three paddles were placed at fixed sampling stations distributed over five selected sites. Continuous egg-collections yielded more than four million eggs laid into 464 sentinel-ovitraps over one year. The overall positive ovitrap index was 98.5% (over 5,616 trap observations). The egg density index ranged from 100 to 2,500 eggs per trap-cycle, indicating a wide spread and high density of Aedes aegypti (Diptera: Culicidae) breeding populations in all sites. Fluctuations in population density over time were observed, particularly a marked increase from January on, or later, according to site. Massive egg-collection carried out at one of the sites prevented such a population outbreak. At intra-site level, egg counts made it possible to identify spots where the vector population is consistently concentrated over the time, pinpointing areas that should be considered high priority for control activities. The results indicate that these could be promising strategies for detecting and preventing Ae. aegypti population outbreaks.

Immunogenicity, reactogenicity and consistency of production of a Brazilian combined vaccine against diphtheria, tetanus, pertussis and Haemophilus influenzae type b

A randomized, double-blinded study evaluating the immunogenicity, safety and consistency of production of a combined diphtheria-tetanus-pertussis-Haemophilus influenzae type b vaccine entirely produced in Brazil by Bio-Manguinhos and Instituto Butantan (DTP/Hib-BM) was undertaken. The reference vaccine had the same DTP vaccine but the Hib component was produced using purified materials supplied by GlaxoSmithKline (DTP/Hib-GSK), which is registered and has supplied the Brazilian National Immunization Program for over more than five years. One thousand infants were recruited for the study and received vaccinations at two, four and six months of age. With respect to immunogenicity, the vaccination protocol was followed in 95.6% and 98.4% of infants in the DTP/Hib-BM and DTP/Hib-GSK groups, respectively. For the Hib component of the study, there was 100% seroprotection (>0.15 µg/mL) with all three lots of DTP/Hib-BM and DTP/Hib-GSK. The geometric mean titer (GMT) was 9.3 µg/mL, 10.3 µg/mL and 10.3 µg/mL for lots 1, 2 and 3 of DTP/Hib-BM, respectively, and the GMT was 11.3 g/mL for DTP/Hib-GSK. For diphtheria, tetanus and pertussis, seroprotection was 99.7%, 100% and 99.9%, respectively, for DTP/Hib-BM, three lots altogether and 99.2%, 100% and 100% for DTP/Hib-GSK. GMTs were similar across all lots and vaccines. Adverse events rates were comparable among the vaccine groups. The Brazilian DTP/Hib vaccine demonstrated an immunogenicity and reactogenicity profile similar to that of the reference vaccine.

Cloning, expression and characterisation of an HtrA-like serine protease produced in vivo by Mycobacterium leprae

Members of the high temperature requirement A (HtrA) family of chaperone proteases have been shown to play a role in bacterial pathogenesis. In a recent report, we demonstrated that the gene ML0176, which codes for a predicted HtrA-like protease, a gene conserved in other species of mycobacteria, is transcribed by Mycobacterium leprae in human leprosy lesions. In the present study, the recombinant ML0176 protein was produced and its enzymatic properties investigated. M. lepraerecombinant ML0176 was able to hydrolyse a variety of synthetic and natural peptides. Similar to other HtrA proteins, this enzyme displayed maximum proteolytic activity at temperatures above 40°C and was completely inactivated by aprotinin, a protease inhibitor with high selectivity for serine proteases. Finally, analysis of M. leprae ML0176 specificity suggested a broader cleavage preference than that of previously described HtrAs homologues. In summary, we have identified an HtrA-like protease in M. lepraethat may constitute a potential new target for the development of novel prophylactic and/or therapeutic strategies against mycobacterial infections.

Persistence of experimental Rocio virus infection in the golden hamster (Mesocricetus auratus)

Rocio virus (ROCV) is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus). The hamsters were infected intraperitoneally with 9.8 LD50/0.02 mL of ROCV and later anaesthetised and sacrificed at various time points over a 120-day period to collect of blood, urine and organ samples. The viral titres were quantified by real-time-polymerase chain reaction (qRT-PCR). The specimens were used to infect Vero cells and ROCV antigens in the cells were detected by immunefluorescence assay. The levels of antibodies were determined by the haemagglutination inhibition technique. A histopathological examination was performed on the tissues by staining with haematoxylin-eosin and detecting viral antigens by immunohistochemistry (IHC). ROCV induced a strong immune response and was pathogenic in hamsters through neuroinvasion. ROCV was recovered from Vero cells exposed to samples from the viscera, brain, blood, serum and urine and was detected by qRT-PCR in the brain, liver and blood for three months after infection. ROCV induced histopathological changes and the expression of viral antigens, which were detected by IHC in the liver, kidney, lung and brain up to four months after infection. These findings show that ROCV is pathogenic to golden hamsters and has the capacity to cause persistent infection in animals after intraperitoneal infection.

Environmental influences on antibody-enhanced dengue disease outcomes

Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.0025), no significant differences were detected between the SS experimental groups (Kaplan-Meyer log-rank test, p = 0.089). Survival curves from EE and IE animals infected with the AED regimen were extended after corticoid injection and this effect was greater in the EE than in the IE group (Kaplan-Meyer log-rank test, p = 0.0162). Under the AED regimen the EE group showed more intense clinical signs than the IE group. Dyspnoea, tremor, hunched posture, ruffled fur, immobility, pre-terminal paralysis, shock and death were associated with dominant T-lymphocytic hyperplasia and presence of viral antigens in the liver and lungs. We propose that the increased expansion of these memory T-cells and serotype cross-reactive antibodies facilitates the infection of these cells by DENV and that these events correlate with disease severity in an EE.

JC polyomavirus infection in candidates for kidney transplantation living in the Brazilian Amazon Region

This study evaluated the relative occurrences of BK virus (BKV) and JC virus (JCV) infections in patients with chronic kidney disease (CKD). Urine samples were analysed from CKD patients and from 99 patients without CKD as a control. A total of 100 urine samples were analysed from the experimental (CKD patients) group and 99 from the control group. Following DNA extraction, polymerase chain reaction (PCR) was used to amplify a 173 bp region of the gene encoding the T antigen of the BKV and JCV. JCV and BKV infections were differentiated based on the enzymatic digestion of the amplified products using BamHI endonuclease. The results indicated that none of the patients in either group was infected with the BKV, whereas 11.1% (11/99) of the control group subjects and 4% (4/100) of the kidney patients were infected with the JCV. High levels of urea in the excreted urine, low urinary cellularity, reduced bladder washout and a delay in analysing the samples may have contributed to the low prevalence of infection. The results indicate that there is a need to increase the sensitivity of assays used to detect viruses in patients with CDK, especially given that polyomavirus infections, especially BKV, can lead to a loss of kidney function following transplantation.

Parasite load and risk factors for poor outcome among children with visceral leishmaniasis. A cohort study in Belo Horizonte, Brazil, 2010-2011

Clinical and laboratory risk factors for death from visceral leishmaniasis (VL) are relatively known, but quantitative real-time polymerase chain reaction (qPCR) might assess the role of parasite load in determining clinical outcome. The aim of this study was to identify risk factors, including parasite load in peripheral blood, for VL poor outcome among children. This prospective cohort study evaluated children aged ≤ 12 years old with VL diagnosis at three times: pre-treatment (T0), during treatment (T1) and post-treatment (T2). Forty-eight patients were included and 16 (33.3%) met the criteria for poor outcome. Age ≤ 12 months [relative risk (RR) 3.51; 95% confidence interval (CI) 1.89-6.52], tachydyspnoea (RR 3.46; 95% CI 2.19-5.47), bacterial infection (RR 3.08; 95% CI 1.27-7.48), liver enlargement (RR 3.00; 95% CI 1.44-6.23) and low serum albumin (RR 7.00; 95% CI 1.80-27.24) were identified as risk factors. qPCR was positive in all patients at T0 and the parasite DNA was undetectable in 76.1% of them at T1 and in 90.7% at T2. There was no statistical association between parasite load at T0 and poor outcome.

Description of the female of Ctenodontina nairae Vieira (Diptera, Asilidae, Asilinae), with new distribution records

Description of the female of Ctenodontina nairae Vieira (Diptera, Asilidae, Asilinae), with new distribution records. The female of Ctenodontina nairae Vieira, 2012 is described for the first time. Description and illustrations of the habitus, wing and terminalia of the female are provided. The distribution is extended to Bolivia and Peru.

Efeitos de sistemas de preparo nas propriedades físicas de um Latossolo Vermelho distrófico

Os sistemas de preparo do solo e o manejo dos resíduos culturais assumem fundamental importância para a sustentabilidade dos sistemas de produção de mandioca nos solos de textura média a arenosa da região Noroeste do Estado do Paraná. O objetivo deste trabalho foi avaliar os efeitos de diferentes sistemas de preparo utilizados para o plantio da cultura da mandioca, em algumas propriedades físicas de um Latossolo Vermelho distrófico. Os tratamentos utilizados foram: plantio sem revolvimento do solo (PSR), preparo mínimo com escarificação (PM) e preparo convencional com aração e gradagem (PC). Nas camadas de 0-0,15 e 0,15-0,30 m, foram avaliadas as seguintes propriedades físicas: a densidade do solo (Ds), a curva de retenção de água no solo, a curva de resistência do solo à penetração e o intervalo hídrico ótimo (IHO). Nos sistemas de preparo com reduzida mobilização do solo (PSR e PM), foram constatados maiores valores de Ds e de resistência do solo à penetração. A curva de retenção de água foi influenciada apenas pela Ds, a qual incorporou os efeitos dos sistemas de preparo, independentemente da camada amostrada. A modelagem da curva de resistência do solo à penetração foi influenciada pelos sistemas de preparo e camadas amostradas, com maior resistência à penetração em PSR > PM > PC, acentuada na camada subsuperficial. Com o aumento da Ds, verificou-se redução do IHO associada aos efeitos da resistência do solo à penetração e da porosidade de aeração que determinaram, respectivamente, os limites inferior e superior de água disponível. Os valores do IHO seguiram a seqüência PC = PM > PSR na camada de 0-0,15 m, não diferindo significativamente na camada de 0,15-0,30 m. O valor de densidade do solo crítica (Dsc), densidade em que IHO = 0, foi menor no PSR e PM, comparado ao PC, o que contribuiu para a menor freqüência de valores de densidade maiores que a Dsc no PC.

Alterações nas propriedades químicas e físicas de um chernossolo com diferentes coberturas vegetais

O agrossistema de Itapetinga, Bahia, tem a pecuária como uma das principais atividades econômicas. Sabe-se que a pecuária é uma atividade que causa impactos diretos no solo, no subsolo e na vegetação. Este estudo teve o objetivo de verificar mudanças nas características químicas e texturais de um solo com diferentes coberturas vegetais na região pastoril de Itapetinga, por meio de amostragens realizadas numa seqüência floresta-capoeira-pasto. As amostras foram coletadas ao longo de uma transecção, com 36 pequenas trincheiras de 60 cm de profundidade, espaçadas de 5 m (12 amostras sob mata, 12 sob capoeira e 12 sob pasto), em três profundidades: 0-10, 10-20 e 20-40 cm. Cada três pontos de coleta, ao longo da transecção, foram tomados como uma amostra composta. Os resultados foram submetidos à análise de variância, e a comparação das médias foi feita pelo teste de Tukey a 5 %. Observaram-se diferenças nas propriedades químicas e na matéria orgânica dos solos estudados. Mudanças na cobertura vegetal original, no sentido floresta - pastagem, foram acompanhadas por uma diminuição nos teores de P, K, Ca, Mg, Al, H, soma de bases, saturação por bases e capacidade de troca catiônica, indicando que, de maneira geral, estas propriedades foram alteradas pela introdução e uso de pastagens. Observou-se, também, diferença significativa na textura do solo com relação ao tipo de vegetação, sendo observados maiores teores de argila na mata, capoeira e pasto, seqüencialmente, e maiores teores de areia no pasto.

Propriedades físico-hídricas de um Latossolo Vermelho submetido a diferentes sistemas de manejo

Uma das práticas mecânicas que podem ser adotadas também em solos sob plantio direto (PD) é a escarificação, que tem por objetivos reduzir a densidade do solo e a sua resistência mecânica à penetração das raízes e aumentar a permeabilidade do solo. O efeito dessas alterações sobre o crescimento e desenvolvimento das plantas e o rendimento de grãos é dependente das condições climáticas vigentes. Em condições de umidade do solo ideal, as limitações físicas tendem a não se manifestar com muita intensidade. Este trabalho teve por objetivo estudar as alterações nas propriedades físico-hídricas de um Latossolo Vermelho distrófico típico, conduzido sob PD e submetido à descompactação por escarificação. Avaliaram-se a densidade do solo, a densidade máxima e umidade ótima de compactação, a densidade relativa, a infiltração da água e a condutividade hidráulica do solo saturado (K0) e não-saturado (Kteta), por meio de tensiometria a campo. Os resultados indicaram que a área com escarificação (PDE) apresentou infiltração de água e K0 superiores aos do PD, demonstrando ser uma alternativa para conservação do solo e da água, com efeitos que permaneceram por mais de um ano. A densidade do solo não apresentou diferenças entre os manejos, e o PDE mostrou menor densidade relativa. Conclui-se que a escarificação em solos sob PD tem efeitos por até 24 meses e melhora as condições para conservação do solo e da água.

Produção de laranja 'Pêra' em sistemas de preparo de solo e manejo nas entrelinhas

O preparo convencional do solo utilizado na implantação de pomares cítricos com base na remoção da cobertura vegetal e no revolvimento do solo em área total, assim como o manejo de pomares com eliminação da cobertura vegetal das entrelinhas, têm causado erosão e redução da fertilidade dos solos, com reflexos negativos sobre as plantas cítricas e o ambiente. O objetivo deste estudo foi avaliar sistemas de manejo que contribuam para controle da erosão e melhoria da fertilidade de Argissolos originados do arenito Caiuá, cultivados com citros no noroeste do Paraná. Foram avaliados dois sistemas de preparo do solo: convencional (PC), em área total, e preparo em faixas (PF), de 2 m de largura, com diferentes formas de manejo nas entrelinhas. O estudo foi realizado em um pomar de laranja 'Pêra' (Citrus sinensis) enxertada em limoeiro 'Cravo' (Citrus limonia), em um Argissolo Vermelho distrófico latossólico. O experimento foi implantado em área ocupada por pastagem (Brachiaria humidicola), em agosto de 1993, no espaçamento de 7 x 4 m, em delineamento de blocos ao acaso, com três repetições e seis tratamentos, sendo: (1) PC e cultivo intercalar com abacaxi, sucedido por controle da vegetação espontânea com herbicida pós-emergente; (2) PC e cobertura vegetal com a leguminosa Calopogonium mucronoides; (3) PC e cobertura vegetal com a leguminosa perene amendoim forrageiro Arachis pintoi; (4) PC e cobertura vegetal com gramínea mato-grosso ou batatais Paspalum notatum; (5) PC e cobertura com vegetação espontânea da gramínea Brachiaria humidicola; e (6) PF e manutenção da gramínea (pastagem) remanescente (Brachiaria humidicola). De 1996 a 2005, foram avaliadas a composição química do solo e das folhas e a produção de frutos. No solo, foram observados incrementos significativos no teor de C orgânico (CO) nos tratamentos 4 e 6, em relação aos tratamentos 1 e 3. Não houve diferenças significativas entre os tratamentos para produção acumulada de frutos nas safras de 1996 a 2005. O preparo de solo em faixas, com manutenção de gramínea remanescente nas entrelinhas, mostrou-se apropriado para implantação dos pomares. As plantas de cobertura permanente utilizadas nas entrelinhas do pomar não comprometeram a produção de laranja, sendo importantes para melhoria da fertilidade do solo. As gramíneas foram mais indicadas que as leguminosas como cobertura vegetal nas entrelinhas do pomar.