D. G. Ubiali

Detecção de Brucella abortus em linfonodos de búfalas (Bubalus bubalis) em diferentes fases da gestação

O objetivo do presente trabalho foi verificar a presenca do DNA de Brucella abortus e caracterizar as lesoes causadas por esse agente em linfonodos de bufalas. Foram utilizadas 19 bufalas em diversos estagios de gestacao, sorologicamente positivas para brucelose, submetidas ao abate sanitario, das quais se coletou fragmentos de diversos linfonodos. A idade fetal foi determinada atraves de exames ultrassonograficos associados a mensuracao dos fetos durante a necropsia. Amostras foram coletadas e submetidas a qPCR e histopatologia. A deteccao de DNA de B. abortus nos linfonodos das bufalas avaliadas foi verificada a partir do quarto mes de gestacao em sete bufalas e em uma bufala pos-paricao. Os achados histologicos foram linfadenite aguda a cronica. A presenca de DNA de B. abortus foi detectada em todos os grupos de linfonodos avaliados, sendo que os linfonodos mais acometidos foram os mamarios.

Paratuberculosis in buffaloes in Northeast Brazil

Several farms in the Northeast of Brazil were investigated for Mycobacterium avium subsp. paratuberculosis infection in order to identify the occurrence of paratuberculosis in buffaloes. Samples were obtained from 17 farms, two slaughter houses, and a quarantine area in the Northeast. About 15,000 buffaloes of the Murrah, Mediterranean, and Jafarabadi breed as well as their crossbreeds were evaluated for meat, dairy, and mixed farms with semi-intensive or extensive breeding practices. For diagnostic purposes, postmortem and histopathological examination, including Ziehl-Neelsen test of fecal smears and scraped intestinal mucosa were performed. PCR was applied for fecal samples, mesenteric lymph nodes, and intestines. Six Johne’s disease-positive farms, which together with those previously identified, indicate that the disease is spread through the Brazilian Northeast, similar to what occurs in cattle herds in other regions of the country. The increase in prevalence of paratuberculosis is a consequence of introduction of animals from other regions without adequate veterinary assistance and due to the little official attention paid to this initially silent and chronic disease.

Teores de cobre, zinco e ferro no fígado de búfalos (Bubalus bubalis) com paratuberculose

In order to study copper, zinc and iron concentration in the liver of buffaloes with paratuberculosis (PTB), 13 buffalo cows above three years of age of the Murrah and Mediterranean races or their crosses were used. They originated from two farms in the municipalities of Sao Luis and Sao Mateus, state of Maranhao, Brazil. The animals were selected according to clinical signs of paratuberculosis, as diarrhea, dehydration and submandibular edema. Rectal biopsies for detection of Mycobacterium avium subsp. paratuberculosis (Map) through PCR in real time (qPCR) and Ziehl-Neelsen (ZN) stain were performed on all animals. Seven buffaloes revealed positive and six were negative for PTB. They were separated into two groups: Group 1 contained seven buffaloes positive for paratuberculosis, and Group 2 contained six animals negative for paratuberculosis. They were euthanized and postmortem examination was performed for the collection of various tissue samples to be fixed in 10% formalin for histopathology; also liver tissue samples were collected to be frozen for chemical analysis of trace minerals (Cu, Zn and Fe). Postmortem showed that all buffaloes with PTB had brown colored mesenteric lymphnodes, indicating hemosiderosis. One buffalo had brown spots on the mucosa of the small intestine. Histopathology revealed moderate to severe hemosiderosis of the spleen in buffaloes of Group 1. All animals positive for PTB showed micromineral levels below the reference values. The average Cu concentration in buffaloes with PTB was only 18.0ppm and the one of Zn only 68.6ppm. In Group 2, negative for PTB, the average Cu concentration was 113.7ppm and the one of Zn 110.0ppm. Fe concentrations in buffaloes of both groups were high (>669ppm). The analysis of trace elements in the liver confirmed copper deficiency, but also showed low levels of zinc and high levels of iron. Based on clinical and pathological findings, and the micromineral concentrations found in the liver, it is concluded that paratuberculosis could lead to mineral deficiency and worsen the clinical condition of the buffaloes.

Diagnóstico de paratuberculose por biópsia retal em búfalos

Paratuberculosis in a herd of buffaloes was studied in the municipality of Sao Mateus, Maranhao, Brazil. Rectal biopsies were performed in 140 male and female Murrah, Mediterranean and crossbreed buffaloes older than 3 years. Postmortem examination of 11 buffaloes was performed to compare the rectal biopsies with possible lesions in mesenteric nodes and the intestine. The history of the herd and clinical examination revealed progressive weight loss and non-responsive antimicrobial diarrhea, dehydration and submandibular edema. Rectal biopsies showed in six buffaloes microscopically suggestive lesions for paratuberculosis through hematoxilin-eosin staining (HE), characterized by moderate multifocal granulomatous enteritis with epithelioid cell infiltration. In four buffaloes Langhans giant cells were found. In 15 buffaloes lymphocytic infiltrate was observed in the lamina propria of the large intestine. Ziehl-Neelsen staining (ZN) revealed in 4.3% (6/140) acid-fast bacilli in the rectal mucosa. Real time PCR amplified to 5.71% (7/140) Mycobacterium avium subsp. paratuberculosis (Map) DNA. 11 buffalos were submitted to postmortem examination, gross examination revealed augmented mesenteric nodes with whitish areas in the cut surface. The mucosa of the small intestine was irregular and thickened, with evident traverse folds and Peyer plates. The brownish intestinal content was fluid, the ileocecal valve area thickened and edematous with evident lymphatic vessels. Histological lesions in the mesenteric lymph node and small intestine four buffalo were compatible with those already described in the literature, and presented acid-fast bacilli by ZN staining and amplification of Map genetic material in qPCR. The concordance between the rectal biopsy and the postmortem samples was in agreement with the Kappa test (K=0.792) and was considered substantial or high. The rectal biopsy showed to be promising and can be used by practitioners, together with other techniques, for antemortem diagnosis in buffalo herds suspected to be affected by paratuberculosis. Samples obtained by rectal biopsy were suitable for ZN staining and real time PCR. Rectal biopsy can be used as a tool for diagnosis and control of Johne´s disease in buffaloes to select and eliminate positive animals within the herd and decrease gradually the spread of Map.