Equine immune-mediated hemolytic anemia associated with Clostridium perfringens infection.

This research article examined the relationship between the bacteria Clostridium perfringens and immune-mediated hemolytic anemia in horses. The researchers used a sample equine case and retrospectively studied eight other horse cases to identify and analyze any abnormal blood conditions found when this type of bacterial infection is present.

Study Design and Methodology

• The basis of this research was an examination of a 7-year-old Foreign Warm-Blood horse, who was showing signs of anemia and had a cervical abscess.
• A series of Complete Blood Counts (CBCs) and reticulocyte counts were carried out by using an Advia 120 analyzer and evaluation of Wright’s-stained smears to study the horse’s blood conditions closely.
• Case records of equine Clostridium spp.myositis or subcutaneous emphysema over a 7-year period were pulled from the University of Minnesota Veterinary Teaching Hospital database for a retrospective analysis.
• Detailed clinical, hematologic, and microbiological findings from all the cases studied were systematically recorded.

Findings and Conclusions

• Clostridium perfringens genotype A, a specific type of bacteria, was isolated from the neck wound of the main sample horse. The gelding’s CBC exhibited severe regenerative anemia, intravascular hemolysis, and RBC (red blood cell) agglutination, which evidence the immune system’s aggressive response to red blood cells.
• Direct Coombs’ test of the horse turned out positive – suggesting the presence of antibodies that could cause the immune system to attack and destroy the horse’s own red blood cells, leading to hemolytic anemia.
• A considerable number of spheroechinocytes (abnormally shaped red blood cells) were observed, and an unusually high reticulocyte count was noted, indicating that the horse’s body was trying to make new red blood cells to replace the ones being destroyed.
• Among the eight retrospective cases, it was noticed that all the horses with myositis (inflammation of muscle tissues) had their cervical region affected, five were anemic, one had a positive direct Coombs’ test, and two exhibited increased numbers of echinocytes and spheroechinocytes.
• The presence of type III echinocytes or spheroechinocytes was found to be potentially useful in diagnosing immune-mediated hemolytic anemia related to clostridial infections in horses.
• Automated reticulocyte counts could help in detecting very low levels of reticulocytosis (the increased production of reticulocytes) in horses suffering from hemolytic anemia.