Pedro Manuel Leal Germano

Estudo da ocorrência de enteroparasitas em hortaliças comercializadas na região metropolitana de São Paulo, SP, Brasil: I - Pesquisa de helmintos

Vegetables in natura, commercially traded in the metropolitan area of S. Paulo, were analysed by the appropriate methodology with a view to discovering an identifying the paths of transmission of enteroparasites of medical interest. The vegetables under study consisted of 50 samples of each variety listed below: lettuce (Lactuca sativa) -oily leaves and crisphead varieties, endive (Chicorium sp) and water-cress (Nasturtium Officinale). Results showed high rates of contamination in all the vegetable varieties analysed. However, the water-cress was that which presented the highest frequencies of enteroparasites. The endive presented middle values ranking, in general, between the lettuces and the water-cress. Though high, the average number of helminth eggs and larvae obtained per 100 gr. of sample did not present statistically significant differences as between the four vegetable varietities studied. A great variety of helminths and protozoans such as occur frequently in the resident population of the metropolitan area of S. Paulo, were observed in the samples. However, the most frequent were: hookworms and Ascaris sp. Eggs of Toxocara sp, Fasciola sp and Trichostrongylidae were also recovered from the samples thus corroborating the occurrence of vegetables contamination with faeces of domestic animals. In view of the results obtained, the importance of these kinds of food in the transmission of enteroparasites is stressed, as well as the need for actions which improve the sanitary conditions of these products.: Vegetables in natura, commercially traded in the metropolitan area of S. Paulo, were analysed by the appropriate methodology with a view to discovering an identifying the paths of transmission of enteroparasites of medical interest. The vegetables under study consisted of 50 samples of each variety listed below: lettuce (Lactuca sativa)-oily leaves and crisphead varieties, endive (Chicorium sp) and water-cress (Nasturtium Officinale). Results showed high rates of contamination in all the vegetable varieties analysed. However, the water-cress was that which presented the highest frequencies of enteroparasites. The endive presented middle values ranking, in general, between the lettuces and the water-cress. Though high, the average number of helminth eggs and larvae obtained per 100 gr. of sample did not present statistically significant differences as between the four vegetable varieties studied. A great variety of helminths and protozoans such as occur frequently in the resident population of the metropolitan area of S. Paulo, were observed in the samples. However, the most frequent were: hookworms and Ascaris sp. Eggs of Toxocara sp, Fasciola sp and Trichostrongylidae were also recovered from the samples thus corroborating the occurrence of vegetables contamination with faeces of domestic animals. In view of the results obtained, the importance of these kinds of food in the transmission of enteroparasites is stressed, as well as the need for actions which improve the sanitary conditions of these products.Hortalicas in natura, comercializadas na regiao metropolitana de Sao Paulo, SP (Brasil), foram analisadas atraves de metodologia propria, visando a pesquisa e a identificacao de formas de transmissao de helmintos intestinais de interesse medico. As hortalicas examinadas, constituidas de 50 amostras de cada variedade, foram de: alface (Lactuca sativa), variedades lisa e crespa, escarola (Chichorium sp) e agriao (Nasturtium officinale). Os resultados evidenciaram elevados percentuais de contaminacao em todas as variedades analisadas, porem, as frequencias de helmintos foram maiores no agriao. A escarola apresentou valores medios, geralmente situados entre as alfaces e o agriao. Os numeros medios de ovos e larvas por 100 gramas de amostra, embora elevados, nao apresentaram diferencas estatisticamente significantes entre as quatro variedades de hortalicas estudadas. Uma grande variedade de helmintos, de ocorrencia frequente na populacao residente na Regiao Metropolitana de Sao Paulo, foi observada nas amostras. Os mais frequentes, no entanto, foram: ancilostomideos e Ascaris sp. Recuperaram-se tambem ovos de Toxocara sp, Fasciola sp e de tricostrongilideos, comprovando a ocorrencia de contaminacao das hortalicas por fezes de animais domesticos. Considerando-se os resultados obtidos, ressalta-se a importância das hortalicas na transmissao de helmintiases intestinais, bem como a necessidade de medidas que propiciem uma melhoria na qualidade higienico-sanitaria destes alimentos.

Estudo da ocorrência de enteroparasitas em hortaliças comercializadas na região metropolitana de São Paulo - SP, Brasil: II - Pesquisa de protozoários intestinais

: Vegetables in nature, commercially traded in the metropolitan area of S. Paulo, Brazil, were analyzed by means of the appropriate methodology with a view to discovering and identifying protozoan cysts of medical interest. The vegetables under study consisted of 50 samples of each of the varieties listed below: lettuce (Lactuca sativa)-oily leaves and crisp-head varieties, endive (Chicorium sp) and watercress (Nasturtium officinale). Results showed high rates of contamination in all the varieties of vegetable analysed. However, the watercress was the one which presented the highest frequencies of enteroparasites. Both the oily leaves and crisp-head varieties of lettuce presented the lowest rates of contamination, whereas endive presented values ranking, in general, between those of the lettuce and those of the watercress. A great variety of those protozoans which occur frequently in the population resident in the metropolitan area of S. Paulo were observed in the samples, the most frequent being Entamoeba sp (with 4 and 8 nuclei) and Giardia sp. Cysts of Iodamoeba sp, Endolimax sp and Chilomastix sp were also recovered from the samples, thus corroborating the occurrence of high rates of fecal contamination. The significance of these kinds of food in the transmission of protozoans is discussed in the light of the results obtained.

Aflatoxinas: conceitos sobre mecanismos de toxicidade e seu envolvimento na etiologia do câncer hepático celular

Current concepts derived from intensive research over the last decade, on biotransformation, mechanisms of toxicity and evidences for the involvement of aflatoxins in the etiology of human liver cancer are summarily presented. Aflatoxin B1(AFB1), the main metabolite produced by moulds of genus Aspergillus, exerts its effects after conversion to the reactive compound AFB1-epoxide, by the action of cytochrome P450-dependent enzymes. This epoxide can form derivatives with cellular macromolecules, including proteins, RNA and DNA. The reaction with DNA occurs with guanines in the codon 249 of tumor suppressor gene p53. Primary biotransformation of AFB1 also produces hydroxylated and less toxic derivatives, such as aflatoxins Q1 and P1. Differences intra and interspecies in the pathways of activation/detoxification are directly related to the susceptibility of animals to aflatoxin effects. In humans, studies of individual biomonitoring of AFB1 metabolites such as AFB1-N7-guanine have demonstrated that aflatoxins constitute an important risk factor for hepatocellular carcinoma (HCC) in exposed populations. Some of these studies also show a synergistic action between aflatoxins and the hepatitis B virus in the development of human HCC. In view of these concepts, and taking into account the frequent detection of aflatoxins in Brazilian foodstuffs, the need for investigation into the level of exposure to these toxins and its impact on human health is stressed.Foram revistos os conceitos de maior relevância sobre mecanismos de toxicidade e evidencias do envolvimento das aflatoxinas na etiologia do câncer hepatico humano. A aflatoxina B1 (AFB1), principal metabolito produzido por fungos do genero Aspergillus, manifesta seus efeitos toxicos apos conversao hepatica em AFB1-epoxido, o qual reage com macromoleculas celulares, incluindo proteinas, RNA (acido ribonucleico) e DNA (acido desoxirribonucleico). A reacao com o DNA ocorre atraves da ligacao com guaninas, ao nivel do codon 249, do gene supressor de tumores p53. Em seres humanos, estudos de biomonitoramento individual de derivados AFB1-N7-guanina tem demonstrado que as aflatoxinas constituem importantes fatores de risco, com uma provavel interacao sinergistica com o virus da hepatite B, para o desenvolvimento do carcinoma hepatocelular em populacoes expostas. Considerando-se a ocorrencia frequente das aflatoxinas em produtos alimenticios, no Brasil, ressalta-se a necessidade de estudos que avaliem criteriosamente o impacto dos niveis de exposicao a estas toxinas sobre a saude humana.

Performance of the ELISA test for swine cysticercosis using antigens of Taenia solium and Taenia crassiceps cysticerci

Studies were conducted to evaluate antigens of Taenia solium (Tso) and Taenia crassiceps (Tcra) cysticerci in the ELISA test for the diagnosis of swine cysticercosis. The samples analyzed were cysticercosis positive and negative control sera and heterologous sera. Four antigens were assayed: vesicular fluid (VF) and crude (T) Tcra and scolex (S) and crude (T) Tso. All antigens showed good performance, but VF-Tcra was the best followed by T-Tcra. Sensitivity rates of ELISA were respectively, in 2nd and 3rd standard deviation cut-offs, 96.0 and 80.0% for the VF antigen and specificity of 97.5 and 100.0%. Cross-reactivity was verified only for hidatidosis and ascaridiosis. Due to the high performance observed, the ELISA test using Tcra antigens should be recommended for the diagnosis of swine cysticercosis.

Rabies laboratory diagnosis: peculiar features of samples from equine origin

Rabies laboratory diagnosis is performed by using microscopic examination for Negri bodies (MEN), fluorescent-antibody test (FAT) and mouse inoculation test (MIT). In the majority of cases, when specimens are properly collected and conserved and the laboratory worker has good experience, agreement among employed techniques is verified. Comparing the sensitivity of these three diagnosis techniques in 3,713 samples (hippocampus and brain stem) received during 1981-1994 period, being 3,010 from bovine (983 positives) and 703 from equine (111 positives) species, it was observed that in equine rabid samples, this agreement was not maintained. For the latter specie, only in few opportunities the Negri bodies could be observed. With respect to FAT, the test detected a lower porcentage of positive equine samples compared to bovine species. Statistical analysis demonstrated that the difference was significative. Mouse inoculation test proved to be more sensitive. However, a significant difference in mice incubation period was observed for samples from both species. The absence of inclusion bodies and the longer incubation period for equine samples suggest that rabies pathogenesis studies for equine species have to be intensified.

Avanços na pesquisa da raiva

Recent advances in research into rabies, based on the technological process of the biological sciences mainly molecular biology and genetic engineering, are mentioned. The current knowledge of the characteristics, properties pathogeny and immunology of the rabies views is presented, as well as the development of new diagnostic and vaccine evaluation techniques. The epidemiological importance of the identification of different immunogenic rabies virus strains and the role in immunoprophylaxis of the production of highly immunogenic vaccines, are set out.

ELISA test for the diagnosis of cysticercosis in pigs using antigens of Taenia solium and Taenia crassiceps cysticerci

In the present study ELISA was standardized for the diagnosis of swine cysticercosis based on necropsy parameters and confirmed positive and negative control sera. Serum samples from pigs with other infections were also assayed to determine possible cross-reactions. Four antigens were assayed: from Taenia crassiceps vesicular fluid (VF-Tcra) and crude larvae extract (T-Tcra), and from Taenia solium extracts of scolex (S-Ts) and of larvae (T-Ts). A checkerboard evaluation of antigen, serum and conjugate dilutions, as well as the use of Tween-20 and skim cow milk in wash and blocking solution had a marked effect on improving ELISA performance. All the antigens showed a good performance, but VF-Tcra was the best, with 96.0% and 80.0% sensitivities for cut-offs respectively at 2sd and 3sd, and corresponding specificities of 97.5% and 100.0%. Cross-reactivity was observed only with hydatidosis and ascaridiosis. In view of the high performance observed, the ELISA test should be recommended for the diagnosis of cysticercosis in suspected swine in slaughterhouses and for the screening of cysticercosis in swine production. These results will support integrated measures of cysticercosis control throughout the chain of swine production, effectively contributing to public health.

Ocorrência de anticorpos antitoxoplasma em gatos infectados naturalmente pelo vírus da imunodeficiência dos felinos

Foram avaliadas, pela tecnica de imunofluorescencia indireta, a frequencia e a magnitude dos titulos de anticorpos antitoxoplasma (Toxoplasma gondii, Nicolle; Manceaux, 1909), em gatos infectados naturalmente pelo virus da imunodeficiencia dos felinos (VIF). Utilizaram-se 115 amostras de soro sanguineo de gatos negativos ao virus da leucemia felina que foram divididas em 3 grupos. Os 22 animais do grupo I eram positivos ao VIF. Os 58 animais que compuseram o grupo II eram doentes porem negativos na pesquisa de anticorpos anti-VIF e os 35 felinos do grupo III eram higidos e negativos ao VIF. Os resultados obtidos permitiram concluir que a frequencia de anticorpos antitoxoplasma foi maior no grupo I do que nos grupos II e III. A analise estatistica mostrou forte associacao entre a infeccao pelo VIF e a presenca de anticorpos antitoxoplasma. Nao se observou diferenca entre a magnitude dos titulos de anticorpos antitoxoplasma nos animais positivos e negativos ao VIF. Embora gatos que desenvolvam imunidade raramente eliminem oocistos, nao se sabe exatamente como esta imunidade pode influenciar a eliminacao de oocistos naqueles gatos infectados pelo VIF. Em face da alta frequencia de anticorpos antitoxoplasma observada nos animais positivos ao VIF, acredita-se que todos os gatos positivos a esse virus devam ser avaliados quanto a presenca de anticorpos antitoxoplasma.

Identification of Staphylococcus aureus Carrying the mecA Gene in Ready-to-Eat Food Products Sold in Brazil

Since Staphylococcus aureus can cause several types of diseases, the development of antibiotic resistance poses an even greater threat to public health. S. aureus is known to possess the adaptive capability to promptly respond to antibiotics, making it resistant and increasingly difficult to treat; methicillin-resistant strains of S. aureus are a major concern with regard to this species. Previous studies reported the identification of methicillin-resistant S. aureus in food, demonstrating that this can represent a source of S. aureus which may carry the mecA gene. Fifty-seven S. aureus isolates, previously obtained from different types of food, were screened by polymerase chain reaction with specific primers for the mecA gene, which mediates methicillin resistance. Five (9%) isolates showed the presence of mecA gene, demonstrating that food may contain microorganisms possessing resistance genes. This study emphasizes the need to include food as a possible source of S. aureus carrying mecA gene and the need to monitor these products. Moreover, this is the first report of the presence of mecA genes in S. aureus isolated from ready-to-eat food in Brazil and Latin America.

Immunoblot analysis using antigen from Taenia crassiceps cysticerci in the diagnosis of swine cysticercosis

Se utilizo la tecnica del inmunoblot para el diagnostico de la cisticercosis porcina usando un antigeno total de cisticercos de Taenia crassiceps. Fueron analizados 13 sueros del cerdo con cisticercosis, 30 sueros controles negativos y ocho sueros del cerdo con hidatidosis, asi como nueve del suino con macracantorincosis, 10 con ascaridiosis y ocho con pulmonia. El uso de este antigeno en el inmunoblot con suero de cerdos no se habia publicado previamente. El inmunoblot fue padronizado por analisis de titulacion en bloque mostrando 100.0% de sensibilidad y 96.7% de especificidad. Los peptidos especificos para la cisticercosis en orden de frecuencia fueron: 72-68 kD (100%), 16-15 kD (77%), 39-36 kD (62%), 18-17 kD (54%), 21 kD (31%), 14 kD (23%), 25-23 kD (8%), y 20-19 kD (8%). Reaccion cruzada (72-68 y 18-17 kD) solo se descubrio en una muestra (12.5%) de cerdo con hidatidosis. Debido a sus altas tasas de desempeno, el inmunoblot debe ser util para confirmar el diagnostico de cisticercosis porcina y es mas eficaz que otras pruebas empleadas para este proposito, como examen de la lengua, examen anatomopatologico y ELISA