Bacillary Hemoglobinuria in a Bovine

Abstract

Background: Bacillary hemoglobinuria (BH) is a disease caused by the bacterium Clostridium haemolyticum, an anaerobic microorganism. The main species affected by this bacterium are cattle, especially those from wet fields. These animals are infected by eating pasture contaminated by the agent. The bacteria remain in the liver as spores until there is a condition of anaerobiosis triggered by previous damage to the liver parenchyma. The clinical course of BH is usually acute and fatal, with death occurring between 12 and 24 h after the onset of clinical signs. The purpose of this study is to report a case of bacillary hemoglobinuria in cattle.

Case: On a property located near Lagoa dos Patos, in the state of Rio Grande do Sul, the owner reported that a female Aberdeen Angus, approximately 1-year-old, showed marked muscle weakness, apathy, and isolation from the herd. In addition, the feces and urine were dark and bloody. These clinical signs appeared acutely in the morning and the animal died in the late afternoon of the same day. It is worth mentioning that, according to the owner, the animals had not been vaccinated against clostridiosis. When performing the necropsy, significant alterations were observed in the liver parenchyma, such as grayish areas surrounded by necrotic hyperemia and free serosanguineous fluid in the abdominal cavity. Histopathological examination revealed areas of necrotizing, fibrosing, predominantly neutrophilic hepatitis, characteristic of BH.

Discussion: The diagnosis of this case of bacillary hemoglobinuria was established based on an integrated analysis of clinical signs, epidemiological data, macroscopic and histopathological evaluations. In Rio Grande do Sul, the prevalence of this disease is particularly high in areas with low fields and inadequate drainage, favoring the survival of the pathogen's spores. This case was located near the Patos Lagoon, where the correlation between humid environments and an increased risk of infection is favorable. Although the infection most often affects animals over 2 years of age, contamination can occur in younger animals, as happened in this case of BH. Normally, bacillary hemoglobinuria manifests itself in less than 24 h, and early recognition of clinical signs is extremely important, since therapeutic interventions can be limited and often ineffective in cases of BH. The necropsy findings are in line with the literature on the disease, such as hepatomegaly and multifocal grayish lesions surrounded by necrotic hyperemia in the liver, which are considered pathognomonic of this disease when related to the clinical signs. These specific characteristics help to differentiate bacillary hemoglobinuria from other conditions, such as other clostridial diseases that have an acute course. The lack of strict adherence to vaccination protocols contributes significantly to the high incidence of the disease. Prophylaxis through toxoid vaccination is an essential strategy to prevent bacillary hemoglobinuria, and its implementation should be prioritized, especially in regions of high environmental risk. Lack of vaccination not only exposes animals to a greater risk of infection, but can also have a significant economic impact on rural production, resulting in financial losses for producers. This study is of great relevance as it expands the knowledge regarding BH. It highlights the importance of recognizing the characteristics of this disease, together with macroscopic and microscopic analyses.

Keywords: hemolysis, hepatic necrosis, jaundice, toxin β.

Título: Hemoglobinúria bacilar em um bovino

Descritores: hemólise, icterícia, necrose hepática, toxina β.