Anti-leptospirosis agglutinins in Brazilian capybaras (hydrochoerus hydrochaeris)

The interest in commercial use of wild animals is increasing, especially regarding raising of capybaras. Although this wild species is potentially lucrative for the production of meat, oil and leather, it is suggested as a probable reservoir of leptospires. Methods Due to the economic importance of this species and the lack of studies concerning leptospirosis, the presence of anti-leptospirosis agglutinins was assayed in 55 serum samples of capybaras (Hydrochoerus hydrochaeris) from commercial and experimental breeding flocks located in São Paulo state, Paraná state, and Rio Grande do Sul state, Brazil. Samples were obtained through cephalic or femoral venipunction (5 to 10 mL). Microscopic agglutination test was used according to the Brazilian Health Ministry considering as cut-off titer of 100. Results Out of the 55 samples analyzed, 23 (41.82 %) tested positive. The most prevalent serovar was Icterohaemorrhagiae (56.52 %) in 13 samples, followed by Copenhageni in nine samples (39.13 %), Pomona in four samples (17.39 %), Djasiman and Castellonis in three samples each (13.04 %), Grippotyphosa, Hardjo, Canicola, and Cynopteri in two samples each (8.7 %), and Andamana and Bratislava in one sample each (4.34 %). Conclusions These results suggest the evidence of exposure toLeptospira spp. and the need of new studies to evaluate a higher number of capybaras from different regions to better understand the importance of leptospirosis infection in these animals and verify the zoonotic role of this species as a possible source of infection to humans and other animals.

Anti-leptospirosis agglutinins in Brazilian capybaras (hydrochoerus hydrochaeris)

Abstract Background The interest in commercial use of wild animals is increasing, especially regarding raising of capybaras. Although this wild species is potentially lucrative for the production of meat, oil and leather, it is suggested as a probable reservoir of leptospires. Methods Due to the economic importance of this species and the lack of studies concerning leptospirosis, the presence of anti-leptospirosis agglutinins was assayed in 55 serum samples of capybaras (Hydrochoerus hydrochaeris) from commercial and experimental breeding flocks located in São Paulo state, Paraná state, and Rio Grande do Sul state, Brazil. Samples were obtained through cephalic or femoral venipunction (5 to 10 mL). Microscopic agglutination test was used according to the Brazilian Health Ministry considering as cut-off titer of 100. Results Out of the 55 samples analyzed, 23 (41.82 %) tested positive. The most prevalent serovar was Icterohaemorrhagiae (56.52 %) in 13 samples, followed by Copenhageni in nine samples (39.13 %), Pomona in four samples (17.39 %), Djasiman and Castellonis in three samples each (13.04 %), Grippotyphosa, Hardjo, Canicola, and Cynopteri in two samples each (8.7 %), and Andamana and Bratislava in one sample each (4.34 %). Conclusions These results suggest the evidence of exposure toLeptospira spp. and the need of new studies to evaluate a higher number of capybaras from different regions to better understand the importance of leptospirosis infection in these animals and verify the zoonotic role of this species as a possible source of infection to humans and other animals.

Resposta humoral, carga parasitária e avaliação histopatológica na infecção experimental por Leishmania (Leishmania) chagasi em camundongos BALB/c imunossuprimidos / Humoral response, parasite load and histopathological evaluation in immunossuppressed BALB/c mice experimentally infected by Leishmania (Leishmania) chagasi

O objetivo do estudo foi avaliar a resposta humoral, a carga parasitária e os aspectos histopatológicos presentes no fígado em camundongos BALB/c experimentalmente infectados por L. (L.) chagasi e imunossuprimidos. 96 camundongos foram subdivididos em quatro grupos: controle (I) – sem tratamento; imunossuprimidos (II) – tratamento com dexametasona (DXM) e pentoxifilina (PTX); infectado (III) – infecção por L (L.) chagasi e infectados e imunossuprimidos (IV) - infecção por L (L.) chagasi e tratados com DXM e PTX. O dia de infecção foi considerado como o dia zero e a imunossupressão ocorreu 60 dias pós-infecção. As amostras foram obtidas de cada grupo, em momentos distintos 15, 30, 60, 75 e 90 dias pós-infecção, em que se coletou sangue total, para detecção de IgG1 e IgG2a pelo ensaio imunoenzimático (ELISA), fragmentos de baço e fígado, para detecção da carga parasitária pela técnica de microtitulação em cultura e fragmentos de fígado para o exame histopatológico. Houve diferença significativa na produção das imunoglobulinas e IgG1 foi à subclasse de imunoglobulina mais produzida pelos grupos (P < 0,0001). Quando comparadas a subclasses de imunoglobulinas dentro do mesmo grupo, IgG1 também apresentou médias maiores de produção nos grupos III e IV (P = 0,014 e P = 0,009). E quando se considera o momento, não houve diferenças significativas entre IgG1 e IgG2a. Aos 90 dias pós-infecção foram encontradas diferenças significativas entre as médias de produção de IgG1 e IgG2a, entre os grupos III e IV e o grupo III produziu mais as duas subclasses (P = 0,02). Nos momentos 75 e 90 dias pós-infecção houve produção maior de IgG1 e IgG2a. O Grupo IV apresentou maior carga parasitária (P < 0,005).(...)

This study aimed to evaluate the humoral response, the parasite load and liver histopathological features in BALB/c experimentally infected by L. (L.) chagasi and immunosuppressed Ninety-six mice divided into four groups: control (I) - no treatment; immunosuppressed (II) - Treatment with dexamethasone (DXM) and pentoxifylline (PTX), infected (III) - infection by L. (L.) chagasi and infected and immunosuppressed (IV) - infection by L (L.) chagasi and treated with PTX and DXM. The days of infection was considered as day zero and immunosuppression occurred 60 days post-infection. Samples were obtained from each group at different times 15, 30, 60, 75 and 90 days post-infection, which collected whole blood for detection of IgG1 and IgG2a by test immunoassay (ELISA), fragments of spleen and liver, to detect the parasite load in the technique microtiter culture and fragments of liver for histopathology. Significant differences in production of immunoglobulins, IgG1 was the subclass immunoglobulin produced by most groups (P<0.0001). When comparing the immunoglobulin subclasses within the same group, IgG1 also showed higher average production in groups III and IV (P=0.014 and P=0.009). When one considers the time, there were no significant differences between IgG1 and IgG2a. At 90 days post-infection were significant differences between the means of production of IgG1 and IgG2a between group III and IV and group III produced over the two subclasses (P=0.02). In periods of 75 and 90 days post-infection there was increased production of IgG1 and IgG2a. Group IV showed a higher parasite load (P <0.005).(...)

Serological diagnosis of visceral leishmaniasis by an enzyme immunoassay using protein A in naturally infected dogs

Um ensaio de imunoadsorção enzimática para detecção de anticorpos contra Leishmania chagasi, utilizando antígeno total de formas promastigotas lisados foi desenvolvido. Cinqüenta cães com sintomas clínicos de leishmaniose visceral foram examinados. Esta técnica utilizou anti-IgG de cão conjugado a peroxidase ou proteína A conjugado a peroxidase. Foi verificado que nos animais positivos diagnosticados por exame parasitológico direto o ensaio ELISA utilizando proteína A conjugada a peroxidase (média da densidade óptica ± desvio padrão 2,078 ± 0,631) detecta mais anticorpos do que o sistema utilizando anti-IgG de cão conjugado a peroxidase (média da densidade óptica ± desvio padrão 1,008 ± 0,437), enquanto para os animais negativos o resultado obtido nos dois sistemas de detecção são similares. Esse resultado sugere que o sistema de ELISA utilizando proteína A conjugado a peroxidase pode ser útil na detecção de animais na fase aguda da infecção e desta forma auxiliar na identificação dos animais positivos e no controle desta importante zoonose.