Brazilian researchers who reported the first case of malignant edema caused by the bacterium Clostridium novyi type A say it is advisable to avoid using intramuscular injections in horses for delivering non-antibiotic medications.
The researchers suspect the horse’s infection most likely arose after a vitamin complex was injected into muscle.
Clostridial myositis, also called malignant edema, causes severe necrotizing soft tissue infections.
In domestic animals, these infections are most common in cattle and sheep, with C. septicum, C. chauvoei, C. novyi and C. perfringens being the most common causes.
Horses are less commonly affected by malignant edema, but there are published veterinary reports that describe muscle infections caused by Clostridium species: C. fallax, C. septicum, C. chauvoei, C. sporogenes and, more commonly, C. perfringens.
Clostridium novyi infection in horses is less frequent and usually fatal.
Luana D’avila Farias and his colleagues from the Universidade Federal de Santa Maria describe the first report involving a case of acute myonecrosis – gas gangrene – in a horse caused by C. novyi type A.
The three-year-old horse was admitted to a veterinary hospital due to increased volume and lameness in the left pelvic limb. The increased volume started in the gluteal muscle, where the horse had been given an intramuscular injection of vitamin complex, the researchers noted.
The research team described the testing and treatment involved in the care of the horse.
“The treatment of the horse was performed according the reported protocols for other cases of malignant edema in horses … However, the treatment was not successful; as in other studies of infections with C. novyi, the animal was euthanized on the sixth day of hospitalization.”
The authors, wrting in the Brazilian Journal of Microbiology, said: “Although there is a low incidence of C. novyi infection in horses, it is advisable to use alternative routes for the administration of nonantibiotic medications to avoid intramuscular injections, even in vascularized areas.”
Acute myonecrosis in horse caused by Clostridium novyi type A
Luana D’avila Farias, Marcos Da Silva Azevedo, Maria Elisa Trost, Flávio Desessards De La CôrteII, Luiz Francisco Irigoyen, Agueda Castagna de Vargas.
Braz. J. Microbiol. vol.45 no.1 São Paulo 2014 Epub Apr 08, 2014
The full paper can be read here.