Clostridial diseases diagnosed in herbivores in southern Brazil

Abstract

Background: The genus Clostridium includes a group of Gram-positive, anaerobic bacteria which producing endospores and produce toxins when encounter conditions favorable to their development. These toxins can be produced and absorbed in the intestinal lumen, as occurs in cases of enterotoxemia (Clostridium perfringens), or are produced in areas of tissue necrosis after bacterial infections, as seen in tetanus (C. tetani), blackleg (C. chauvoei) and bacillary hemoglobinuria (C. haemolyticum), or in infections by C. chauvoei, C. novyi and C. septicum frequently associated with cases of malignant edema. The aim of this research was relates the epidemiological and clinicopathological aspects of the clostridiosis observed in the region of infl uence of the Setor de Patologia Veterinária of Universidade Federal do Rio Grande do Sul. Materials, Methods & Results: The necropsy records were reviewed from January 1996 to December 2011 to identify the cases of clostridiosis that were diagnosed. In the period, 4.689 necropsies were performed by the (SPV-UFRGS). A total of 135 cases (2.88%) were associated with clostridiosis. The most prevalent clostridiosis included tetanus (48.15%) in horses, cattle, sheep and goats; botulism (17.04%) in cattle and enterotoxemia (22.96%) in goats. Additional diseases were blackleg (5.93%) in cattle, necrotic myositis/malignant edema in horses and sheep and bacillary hemoglobinuria in cattle, both with 4 cases each (2.96%). Discussion: Tetanus, enterotoxemia, and botulism were the most prevalent clostrodiosis diagnosed at SPV-UFRGS and together accounted for approximately 90% of cases in the period 1996-2011. As for blackleg, bacillary hemoglobinuria, and necrotic myositis/malignant edema, together they represented slightly less than 10% of the clostridioses in the period. The most signifi cant clostridiosis in the period studied was tetanus, affecting cattle, sheep, and horses. There was a large number of cases distributed over many years; probably this occurrence was associated with these species’ (sheep and horse) greater sensitivity to the toxin. In cattle the cases of tetanus in cattle were observed in various outbreaks distributed only in two years, the death of the animals was associated with the contamination of anthelmintic bottles with C. tetani spores. Botulism is an important clostridiosis for bovines. In all the outbreaks of botulism, the cases were concentrated in the hottest periods of the year: summer, late spring, and early fall, as stated in previous reports of botulism. Cases of enterotoxemia were important and observed only in goats. Outbreaks of enterotoxemia were attributed to excessive consumption of concentrated feed, and the disease affected vaccinated and unvaccinated goats alike. Blackleg was apparently less signifi cant in the area of infl uence of the SPV-UFRGS, to the contrary of what was previously repots, when it was considered the most important clostridiosis in cattle in Rio Grande do Sul. It is possible that the prompt recognition of this disease by veterinarians in the fi eld reduced the frequency of requests for diagnostic services. The two less frequent clostridiosis were bacillary hemoglobinuria and necrotic myositis/malignant edema, which occurred in cattle; horses, and sheep, respectively. All the clostridiosis showed a signifi cant presence in the livestock necropsies, but only three (tetanus in horses, sheep and cattle; botulism in cattle, and enterotoxemia in goats) affected an elevated number of animals.