Serological evidence of exposure to tick-borne agents in opossums (Didelphis spp. ) in the state of São Paulo, Brazil / Evidência sorológica de exposição a agentes transmitidos por carrapatos em gambás (Didelphis spp. ) no estado de São Paulo, Brasil

Abstract This work involved a serological investigation of tick-borne pathogens in opossums in eight municipalities of the state of São Paulo, Brazil. Serum samples from 109 opossums (91 Didelphis aurita and 18 Didelphis albiventris) were tested to detect antibodies to Rickettsia rickettsii (Taiaçu strain, 1:64 cut-off) and Ehrlichia canis (São Paulo strain, 1:40 cut-off), by indirect immunofluorescence assay (IFA); and against Borrelia burgdorferi (strain G39/40) by enzyme-linked immunosorbent assay (ELISA). The presence of antibodies to anti-R. rickettsii, anti-E. canis and anti-B. burgdorferi was detected in 32 (29.35%), 16 (14.67%) and 30 (27.52%) opossums, respectively. Opossum endpoint titers ranged from 64 to 1,024 for R. rickettsii, from 40 to 160 for E. canis, and from 400 to >51,200 for B. burgdorferi. These serological results suggest that opossums have been exposed to Rickettsia spp., Ehrlichia spp., and B. burgdorferi-related agents in the state of São Paulo. Our study underscores the need for further research about these agents in this study area, in view of the occurrence of Spotted Fever and Baggio-Yoshinari Syndrome disease in humans in the state of São Paulo, Brazil.

Resumo O presente estudo investigou evidência sorológica de agentes transmitidos por carrapatos em gambás em oito municípios do Estado de São Paulo, Brasil. Amostras de soro de 109 gambás (91 Didelphis aurita e 18 Didelphis albiventris) foram testadas para detecção de anticorpos contra Rickettsia rickettsii (cepa Taiaçu, ponto de corte 1:64) Ehrlichia canis (cepa São Paulo, ponto de corte 1:40), pela reação de imunofluorescência indireta (RIFI); e contra Borrelia burgdorferi (cepa G39/40) pelo teste imunoenzimático (ELISA). A presença de anticorpos anti-R. rickettsii, anti-E. canis e anti-B. burgdorferi foi detectada em 32 (29,35%), 16 (14,67%) e 30 (27,52%) gambás, respectivamente. Os títulos finais variaram de 64 a 1.024 para R. rickettsii, de 40 a 160 para E. canis, e de 400 a >51.200 para B. burgdorferi. Esses resultados sugerem que os gambás foram expostos a agentes relacionados à Rickettsia spp., Ehrlichia spp., e B. burgdorferi no Estado de São Paulo. Neste estudo salienta a necessidade de novas pesquisas sobre esses agentes nessas áreas de trabalho, devido à ocorrência da Febre Maculosa e da Síndrome Baggio-Yoshinari em humanos no Estado de São Paulo, Brasil.

Serological evidence of exposure to tick-borne agents in opossums (Didelphis spp.) in the state of São Paulo, Brazil.

This work involved a serological investigation of tick-borne pathogens in opossums in eight municipalities of the state of São Paulo, Brazil. Serum samples from 109 opossums (91 Didelphis aurita and 18 Didelphis albiventris) were tested to detect antibodies to Rickettsia rickettsii (Taiaçu strain, 1:64 cut-off) and Ehrlichia canis (São Paulo strain, 1:40 cut-off), by indirect immunofluorescence assay (IFA); and against Borrelia burgdorferi (strain G39/40) by enzyme-linked immunosorbent assay (ELISA). The presence of antibodies to anti-R. rickettsii, anti-E. canis and anti-B. burgdorferi was detected in 32 (29.35%), 16 (14.67%) and 30 (27.52%) opossums, respectively. Opossum endpoint titers ranged from 64 to 1,024 for R. rickettsii, from 40 to 160 for E. canis, and from 400 to >51,200 for B. burgdorferi. These serological results suggest that opossums have been exposed to Rickettsia spp., Ehrlichia spp., and B. burgdorferi-related agents in the state of São Paulo. Our study underscores the need for further research about these agents in this study area, in view of the occurrence of Spotted Fever and Baggio-Yoshinari Syndrome disease in humans in the state of São Paulo, Brazil.

Occurrence of antibodies to Toxoplasma gondii in opossums caught in urban areas of Bauru, state of São Paulo, Brazil / Ocorrência de anticorpos para Toxoplasma gondii em gambás capturados na área urbana de Bauru, Estado de São Paulo, Brasil

Toxoplasmosis is one of the most common zoonoses worldwide. It was initially described in rodents and rabbits. There are few data on the morbidity and mortality of this disease among Brazilian marsupial fauna, such as opossums. These animals are of great importance regarding the epidemiology of this disease, given that they are prey for felids and other carnivores. With the aim of ascertaining the serological response to Toxoplasma gondii among marsupials (Didelphis spp.), 38 animals that had been caught in 14 districts of the urban area of the municipality of Bauru, state of São Paulo, were evaluated. The modified agglutination test (MAT) showed that 26.3% (10/38) of the samples analyzed were seropositive. It can be suggested that the opossums' behavior and persistent proximity to human housing results in contact with cats and T. gondii infection, based on the frequency found in this study. This was the first study on the seroprevalence of T. gondii in opossums caught in the urban area of the municipality of Bauru, SP, and it highlights the need for environmental and health authorities of the municipality to monitor this zoonosis.(AU)

A toxoplasmose é uma das zoonoses mais comuns no mundo, tendo sido descrita inicialmente em roedores e em coelhos. Todavia, poucos são os dados sobre morbidade e mortalidade da toxoplasmose nos marsupiais da fauna brasileira, como os gambás, sendo de grande importância na epidemiologia da doença, como presas para felídeos e outros carnívoros. Com o objetivo de verificar a resposta sorológica para Toxoplasma gondii em marsupiais (Didelphis spp.), foram avaliados 38 animais capturados em 14 regiões da área urbana do município de Bauru-SP. Foi encontrada uma frequência, de acordo com o teste de aglutinação modificada (MAT), de 26,3% (10/38) nas amostras analisadas. Pode-se sugerir que o comportamento dos gambás e sua permanência próxima a habitações humanas resultam em contato com gatos e infecção por T. gondii, tendo em vista a frequência encontrada neste estudo. Este é o primeiro estudo de soroprevalência de T. gondii em gambás capturados na área urbana do município de Bauru-SP, alertando-se para a necessidade do monitoramento desta zoonose pelas autoridades de vigilância ambiental e sanitária do município.(AU)

Analysis of the morphology and distribution of argentaffin, argyrophil and insulin-immunoreactive endocrine cells in the small intestine of the adult opossum Didelphis aurita (Wied-Neuwied, 1826).

The aim of this study was to identify and quantify the argyrophil, argentaffin and insulin-immunoreactive cells (IIC) in the small intestine of the opossum Didelphis aurita. Seven adult male specimens of opossums were investigated. The animals were captured, and their blood insulin levels were determined. After euthanasia, fragments of the small intestine were processed for light microscopy and transmission electron microscopy, and submitted to histochemistry and immunohistochemistry for identification of argyrophil and argentaffin endocrine cells, and IIC. Argyrophil and argentaffin cells were identified in the intestinal villi and Liberkühn crypts, whereas IIC were present exclusively in the crypts. Ultrastructure of the IIC revealed cytoplasmic granules of different sizes and electron densities. The numbers of IIC per mm(2) in the duodenum and jejunum were higher than in the ileum (p<0.05). The animals had low levels of blood insulin (2.8 ± 0.78 µIU/ml). There was no correlation between insulin levels and the number of IIC in the small intestine. The IIC presented secretory granules, elongated and variable morphology. It is believed that insulin secretion by the IIC may influence the proliferation of cells in the Liberkühn crypts, and local glucose homeostasis, primarily in animals with low serum insulin levels, such as the opossum.

Inmunodiagnóstico en Didelphis marsupialis usando un antígeno de Paragonimus de Venezuela / Immunodiagnostic in Didelphis marsupialis using an antigen of Venezuelan Paragonimus

Los Paragonimus son trematodos que habitualmente viven en los pulmones de mamíferos carnívoros y omnívoros, entre ellos el hombre. En el oriente venezolano se encuentra el único foco de Paragonimus sp. donde Didelphis marsupialis es el único reservorio demostrado hasta ahora. Con el fin de tener herramientas de inmunodiagnóstico que detecten la presencia de Paragonimus sp. en esta especie, se elaboraron varios reactivos para realizar un ensayo inmunoenzimático ELISA. Entre ellos se obtuvo un antígeno crudo soluble de vermes adultos de Paragonimus y una inmunoglobulina de gallina anti-IgG de Didelphis marsupialis. Los mismos se capturaron en la localidad de Aguas Blancas, municipio Montes, estado Sucre, Venezuela, y se obtuvieron muestras sanguíneas; en el caso de estar infectados, los vermes adultos se extrajeron del pulmón. Los parásitos se homogenizaron y ultracentrifugaron para obtener la fracción soluble del parásito (FSPA) como antígeno para el ELISA y Western blot y detectar los anticuerpos en los Didelphis marsupialis. El análisis electroforético mostró 22 moléculas entre 6 y 82 kDa; por Western blot se presentó un reconocimiento antigénico de 8 moléculas siendo las de 112 kDa y 268 kDa las más reconocidas por los sueros positivos. Los sueros negativos no reconocieron ninguna proteína. La producción de IgY en gallinas permitió desarrollar las técnicas de inmunodiagnóstico para la búsqueda de anticuerpos específicos anti-Paragonimus sp. en Didelphis, cuya aplicación permitirá establecer la vigilancia epidemiológica de estos reservorios en áreas endémicas sin sacrificio de los mismos.

Paragonimus are trematodes that normally live in the lungs of carnivorous and omnivorous mammals such as humans. An outbreak of Paragonimus sp. in which Didelphis marsupialis was the only wild reservoir incriminated was described in eastern Venezuela. In order to have immunological tools to detect the presence of Paragonimus sp. in this reservoir, a whole antigen of the adult worm of this parasite was elaborated. Didelphis marsupialis were captured in the locality of Aguas Blancas, Montes municipality, Sucre state, Venezuela, from which blood samples were obtained and a search for worms was performed in lungs. Worms were homogenized and ultracentrifugated to obtain FSPA to perform immunoassay (ELISA) to detect antibodies in opossums. The electrophoresis analysis showed a pattern of 22 molecules between 6 and 82 kDa; by western blot, the antigenic recognition of 8 antigenic molecules appeared,112 kDa and 268 kDa molecules being the most strongly recognized by positive sera. The negative sera did not recognize any band. The production of IgY in chicken enabled the development of reagents capable of performing a standard immunodiagnosis technique to find specific anti-Paragonimus sp. in Didelphis marsupialis in order to establish epidemiological surveillance of these reservoirs in endemic areas.