Leishmaniose visceral canina: comparação de métodos sorológicos em cães de área indene do Rio Grande do Sul no Brasil / Canine visceral leishmaniasis: Comparison of serological methods in dogs of unsurveyed area of Rio Grande do Sul in Brazil

Neste estudo foi realizado um levantamento da presença de cães soropositivos em canis de 12municípios do Rio Grande do Sul, comparando-se métodos e protocolos de diagnóstico. Comisso, pode-se detectar precocemente uma possível disseminação da doença e, consequentemente,incentivar campanhas de controle e prevenção e evitar futuros surtos. Este estudo foi realizadoem uma área do RS sem diagnóstico de leishmaniose visceral canina (LVC), sendo avaliado umtotal de 165 cães. A pesquisa sorológica foi realizada por meio das técnicas de imunofluorescênciaindireta (IFI), ensaio imunoenzimático (ELISA) e Dual Plate Plataform (DPP). Constataram-setaxas de 33,9 por cento (56/165) na IFI, 6,7 por cento (11/165) no DPP, 3,0 por cento (5/165) na IFI e DPP e 6,1 por cento (10/165)no ELISA. Dentre os resultados confirmados no ELISA, cinco (5/10) foram reagentes na IFI, dosquais, desconsiderando-se os dois que foram soropositivos apenas no ELISA e IFI, resultaram trêscães (3/10) soropositivos no DPP e ELISA, conforme o protocolo atual preconizado pelo Ministérioda Saúde. Também foi feita a comparação entre os testes de diagnóstico para verificar acurácia evalor kappa. Ao considerar somente resultados positivos no DPP e IFI, a acurácia aumentou para94,6 por cento, com um valor Kappa=0,375, ou seja, com uma concordância considerável. Conclui-se quea pesquisa em áreas do RS sem diagnóstico de LVC revelou a presença de cães sororreagentes emquatro municípios do estado: Cachoeira do Sul (2), São Francisco de Assis (1), Dom Pedrito (1) eRio Grande (1)...

This study surveyed the presence of seropositive dogs in kennels of twelve municipalities of RioGrande do Sul (RS), comparing methods and diagnostic protocols. Using this approach we coulddetect a possible spread of the disease, consequently encouraging prevention and control campaigns,and preventing future outbreaks. This study was conducted in an undiagnosed area for caninevisceral leishmaniasis (CVL) of RS and a total of 165 dogs were evaluated. Serological analysiswas performed using the indirect immunofluorescence (IIF), enzyme-linked immunosorbent assay(ELISA) and Dual Plate Platform (DPP). A rate of 33.9 percent (56/165) in the IIF, 6.7 percent (11/165) inDPP, 3.0 percent (5/165) in IIF and DPP and 6.1 percent (10/165) in ELISA was observed. Among the resultsconfirmed by ELISA, five (5/10) were positive by IIF, of which, disregarding two of these five thatwere seropositive only by ELISA and IIF, three dogs (3/10) were seropositive by DPP and ELISA,according to the current protocol recommended by the Ministry of Health. Comparisons betweenthe diagnostic tests to verify accuracy and kappa value were also made. When considering onlythe results positive in DPP and IIF, the accuracy increased to 94.6 percent, with a kappa value of 0.375,therefore, with considerable agreement. It is concluded that the research in undiagnosed areas of RSrevealed the presence of seropositive dogs in four municipalities of the State: Cachoeira do Sul (2),São Francisco de Assis (1) Dom Pedrito (1) and Rio Grande (1)...

Characterization of a virulent Leptospira interrogans strain isolated from an abandoned swimming pool.

Pathogenic Leptospira spp. are the etiological agents of leptospirosis, an important disease of both humans and animals. In urban settings, L. interrogans serovars are the predominant cause of disease in humans. The purpose of this study was to characterize a novel Leptospira isolate recovered from an abandoned swimming pool. Molecular characterization through sequencing of the rpoB gene revealed 100% identity with L. interrogans and variable-number tandem-repeat (VNTR) analysis resulted in a banding pattern identical to L. interrogans serogroup Icterohaemorrhagiae, serovar Copenhageni or Icterohaemorrhagiae. The virulence of the strain was determined in a hamster model of lethal leptospirosis. The lethal dose 50% (LD50) was calculated to be two leptospires in female hamsters and a histopathological examination of infected animals found typical lesions associated with severe leptospirosis, including renal epithelium degeneration, hepatic karyomegaly, liver-plate disarray and lymphocyte infiltration. This highly virulent strain is now available for use in further studies, especially evaluation of vaccine candidates.

Seroprevalence of Toxocara infection in children from southern Brazil.

The seroprevalence of Toxocara canis antibodies in children aged from 1 to 12 yr old was evaluated in Pelotas City, Rio Grande do Sul, Brazil. Human toxocariasis or visceral larva migrans (VLM) was diagnosed with the use of an ELISA based on the T. canis excretory-secretory (TES) antigens; Western blotting was used to confirm the ELISA-positive results. From 427 samples, 50.6% were positive for the presence of anti-TES antibodies. A confirmatory test (Western blot) was carried out on a sample of the ELISA-positive sera (n = 70), and all were positive. The Western blots had specific banding pattern characteristics, where the 30-kDa fraction demonstrated the highest reactivity. This fraction could be important for the specific diagnosis of toxocariasis.

Characterization of a virulent Leptospira interrogans strain isolated from an abandoned swimming pool

Pathogenic Leptospira spp. are the etiological agents of leptospirosis, an important disease of both humans and animals. In urban settings, L. interrogans serovars are the predominant cause of disease in humans. The purpose of this study was to characterize a novel Leptospira isolate recovered from an abandoned swimming pool. Molecular characterization through sequencing of the rpoB gene revealed 100% identity with L. interrogans and variable-number tandem-repeat (VNTR) analysis resulted in a banding pattern identical to L. interrogans serogroup Icterohaemorrhagiae, serovar Copenhageni or Icterohaemorrhagiae. The virulence of the strain was determined in a hamster model of lethal leptospirosis. The lethal dose 50% (LD50) was calculated to be two leptospires in female hamsters and a histopathological examination of infected animals found typical lesions associated with severe leptospirosis, including renal epithelium degeneration, hepatic karyomegaly, liver-plate disarray and lymphocyte infiltration. This highly virulent strain is now available for use in further studies, especially evaluation of vaccine candidates.

Leptospira borgpetersenii from free-living white-eared opossum (Didelphis albiventris): first isolation in Brazil.

Leptospirosis is a zoonotic disease that occurs all over the world, caused by bacteria of the genus Leptospira. Marsupial and didelphidae families are considered susceptible to infection caused by a wide range of Leptospira serovars for which they serve as reservoirs. Thirty-three free-living white-eared opossums (Didelphis albiventris) were captured in Southern Brazil and bodily fluids were collected. From the urine samples it was possible to obtain an isolate identified as Leptospira borgpetersenii by rpoB gene sequencing and belonging to serovar Castellonis by Multilocus Variable-Number Tandem-Repeat Analysis. This is the first report of the isolation of Leptospira spp. from the white-eared opossum in Brazil. In addition, the new strain was also virulent in the hamster model of lethal leptospirosis. The microscopic agglutination test (MAT) was used for detecting the presence of antibodies against Leptospira spp. in white-eared opossum, human, cattle and canine sera using a panel of 59 Leptospira strains that included the new isolate. The inclusion of the new strain in the MAT battery increased the MAT sensitivity for canine sera. These findings suggest that the white-eared opossum is an important reservoir of pathogenic Leptospira spp.

Serum antileptospiral agglutinins in freshwater turtles from Southern Brazil / Aglutininas séricas anti-leptospira em tartarugas de água doce no sul do Brasil

In this study, we observed the presence of antileptospiral agglutinins in freshwater turtles of two urban lakes of Pelotas, Southern Brazil. Forty animals (29 Trachemys dorbigny and 11 Phrynops hilarii) were captured and studied. Attempts to isolate leptospires from blood and urine samples were unsuccessful. Serum samples (titer > 100) reactive to pathogenic strains were observed in 11 animals. These data encourage surveys of pet turtles to evaluate the risk of transmission of pathogenic leptospires to humans.

Neste estudo, observamos a presença de aglutininas anti-Leptospira em tartarugas de água doce de dois lagos urbanos de Pelotas, Sul do Brasil. Quarenta animais (29 Trachemys dorbigny e 11 Phrynops hilarii) foram capturados e estudados. Esforços para isolar leptospiras do sangue e urina não foram bem sucedidos. Amostras de soro positivas (títulos > 100), reativas para cepas patogênicas, foram observadas em 11 animais. Estes dados encorajam inquéritos para avaliação de tartarugas como potenciais transmissoras de leptospiras patogênicas para humanos.

Soroprevalência da infecção leptospiral em capivaras (Hydrochoerus hydrochaeris) abatidas em um frigorífico do Rio Grande do Sul / Seroprevalence of leptospiral infection in capybaras (Hydrochoerus hydrochaeris) in a slaughterhouse of Rio Grande do Sul, Brazil

Capivaras (Hydrochoerus hydrochaeris) são roedores selvagens do continente americano com crescente importância comercial como fonte alternativa de carne para o consumo humano. Nessa espécie, os estudos sobre a soroprevalência da infecção leptospiral são escassos e restritos aos espécimes de vida livre. Relatamos aqui reações positivas para anticorpos aglutinantes anti-leptospiras em 27,3 por cento (6/22) das capivaras abatidas em um frigorífico do Rio Grande do Sul. Os níveis mais altos de anticorpos sugerem infecção pelo sorogrupo Australis devido à reação para uma cepa de referência do sorovar Bratislava e para um isolado canino local do sorovar Australis, caracterizado como Leptospira noguchii. Esses resultados ressaltam que considerável parcela de capivaras criadas em cativeiro podem funcionar como reservatório de leptospiras patogênicas e chamam atenção para o risco ocupacional dos trabalhos que envolvem a criação e o abate dessa espécie animal.

Capybaras (Hydrochoerus hydrochaeris) are wild rodents from the American Continent with increasing importance as a commercial alternative source of meat for human consumption. Studies on seroprevalence for leptospiral infection are scarce and restricted to free living capybaras. We report detection of agglutinating antibodies against leptospires in 27 percent (6/22) of all animals in a slaughterhouse from Rio Grande do Sul. The highest antibody titers predicted Australis as the infecting serogroup due to reactions against a reference strain of serovar Bratislava and a canine local isolate of serovar Australis, characterized as Leptospira noguchii. The data presented in this report highlight that a considerable fraction of capybaras in captivity may behave as reservoir for pathogenic leptospires emphasizing the occupational risk of those who deal with animal farming and slaughter.

Serum antileptospiral agglutinins in freshwater turtles from Southern Brazil.

In this study, we observed the presence of antileptospiral agglutinins in freshwater turtles of two urban lakes of Pelotas, Southern Brazil. Forty animals (29 Trachemys dorbigny and 11 Phrynops hilarii) were captured and studied. Attempts to isolate leptospires from blood and urine samples were unsuccessful. Serum samples (titer > 100) reactive to pathogenic strains were observed in 11 animals. These data encourage surveys of pet turtles to evaluate the risk of transmission of pathogenic leptospires to humans.

Characterization of virulence of Leptospira isolates in a hamster model.

Effort has been made to identify protective antigens in order to develop a recombinant vaccine against leptospirosis. Several attempts failed to conclusively demonstrate efficacy of vaccine candidates due to the lack of an appropriate model of lethal leptospirosis. The purposes of our study were: (i) to test the virulence of leptospiral isolates from Brazil, which are representative of important serogroups that cause disease in humans and animals; and (ii) to standardize the lethal dose 50% (LD(50)) for each of the virulent strains using a hamster (Mesocricetus auratus) model. Five of seven Brazilian isolates induced lethality in a hamster model, with inocula lower than 200 leptospires. Histopathological examination of infected animals showed typical lesions found in both natural and experimental leptospirosis. Results described here demonstrated the potential use of Brazilian isolates as highly virulent strains in challenge experiments using hamster as an appropriate animal model for leptospirosis. Furthermore these strains may be useful in heterologous challenge studies which aim to evaluate cross-protective responses induced by sub-unit vaccine candidates.

Isolation of Leptospira noguchii from sheep.

The main goal of this study was to obtain new isolates of Leptospira spp. from sheep. A total of 10 kidney samples and 44 blood samples were collected from sheep slaughtered in Pelotas, Southern Brazil. One isolate was obtained which was identified by 16S rRNA gene sequencing and serogrouping to be Leptospira noguchii serogroup Autumnalis. Microscopic agglutination test (MAT) evaluation revealed that 4.5% of the sheep sera reacted against the Autumnalis serogroup. This is the first report of isolation of L. noguchii from sheep. Together these findings indicate that L. noguchii infections may be a potentially important veterinary problem in this domestic animal species.

Shiga toxin-producing Escherichia coli (STEC) isolated from healthy dairy cattle in southern Brazil.

Over a period of 1 year, the production of verotoxin was investigated in 1127 Escherichia coli isolated from 243 dairy cattle from 60 small farms in southern Brazil. Vero cell assay was used to detect toxins in culture supernatants from E. coli isolated from bovine feces. Shiga toxin-producing E. coli (STEC) detection rates were 95% (57 of 60) for farms and 49% (119 of 243) for cattle. Prevalence of STEC-positive cattle in the farms ranged from 0 to 100%. Ninety-six percent (315 of 327) of the STEC isolates did not react in the panel of sera used for typing. Twelve isolates, all non-motile, belonged to serogroups previously associated with human diseases, and 67% (8 of 12) were of only two serotypes (O91:H- and sorbitol-fermenting O157:H-). These results indicate that dairy cattle from the region surveyed may be a source of STEC potentially pathogenic for humans.

Leptospirose: relato de cinco casos internados no Hospital Universitário de Rio Grande - RS / Leptospirosis: case report of five cases interned at Rio Grande University Hospital - RS

Os autores relatam cinco casos de leptospirose internados no Hospital Universitário de Rio Grande, no período de março de 1994 a junho de 1995. Quatro pacientes apresentaram a síndrome de Weil e um desenvolveu quadro clínico oligossintomático e anictérico. A confirmação do diagnóstico foi feita através do quadro clínico, da história epidemiológica e de exames laboratoriais inespecíficos e específicos