Malignant Edema in Some Sheep Flocks of Iran

Document Type : Original Articles

Authors

1 of Microbiology, Faculty of Veterinary Medicine, University of Tehran

2 Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran

10.22092/ari.2024.365784.3136

Abstract

Malignant edema is a severe and swiftly fatal disease affecting domestic and wild livestock. The disease manifests following the introduction of Clostridium spp. into wounds or skin damage. Clostridium septicum is commonly linked with malignant edema. This disease, characterized by edema, doughy swelling, and skin necrosis, is underreported in Iran, leading to a lack of awareness among clinicians. Given its underreporting, addressing this issue is essential, prompting current research efforts to understand better its prognosis, bacteriological and molecular diagnosis, clinical signs, and treatment. Upon detecting suspicious signs of malignant edema in three separate flocks with imported breeds, investigations ensued, including regular clinical exams and sample collection from subcutaneous tissue. The impacted livestock consists of five Île-de-France sheep and two Romane rams, with one Île-de-France ram succumbing to the disease. The bacteriological procedure, including Gram staining and isolation of the causative agent, was meticulously carried out using the standard method. The PCR assay was conducted to validate the existence of C. septicum and reject the presence of Clostridium chauvoei by employing specific primers. The diagnosis of malignant edema in the affected sheep was confirmed through clinical, macroscopic, and bacteriological examinations, all of which corroborated the presence of C. septicum. The PCR assay demonstrated the presence of the C. septicum, verifying the bacteriological procedure. Initial signs of the infection included depression, weakness, high fever, and colic, followed by regional pain, crepitation, swelling characterized by a doughy consistency, edema, pain, and necrosis. The study highlights the potential for preventing malignant edema-related fatalities through early diagnosis and antibiotic intervention (Penicillin and Streptomycin). However, it notes a persistent challenge: the inability to repair necrotic tissue at the lesion site. Malignant edema, not being a prominently warned disease and with vaccinations available against its causative agent, has received comparatively less focus from clinicians and researchers in Iran.

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