What is Salmonellosis in Horses?
Diagnosis
Horses are diagnosed with Salmonella based on clinical signs, evidence of low numbers of white blood cells (neutropenia), and identification of the bacteria by fecal culture. PCR testing may help to more rapidly identify Salmonella.
Multiple fecal cultures may be necessary to identify low-level shedders because the microorganism is shed in the feces intermittently and in small numbers.
Treatment
Treatment for salmonellosis is primarily supportive, consisting of fluid and electrolyte administration, as well as the use of intestinal protectants. Systemic antimicrobials are used only when the risk of septicemia is high, such as when treating young, elderly, and immunocompromised patients, or when treating particularly invasive strains such as Salmonella typhimurium. The use of antibiotics has little benefit in treating primary gastrointestinal infections, does not eliminate subclinical states, and may contribute to the development of antibiotic resistance.
Affected horses should be isolated with biosecurity protocols in place.
Prognosis
The prognosis for horses with salmonellosis varies. Some never show clinical signs, whereas others become sick and require veterinary care and treatment. In some cases, horses die as a result of Salmonella infection.
Prevention
Healthy horses are at lower risk of becoming sick with Salmonella than horses that are sick or stressed, so it is important to practice good horse care and management.
To prevent the introduction of Salmonella, it is important to have a biosecurity plan. Do not allow horses to eat off the ground at shows and events, and be sure to disinfect shoes and equipment. Disinfectants, including accelerated hydrogen peroxide (AHP) products (such as Accel®) or two percent Peroxymonosulfate (Virkon™ S) are active against Salmonella. Horses new to the premises should be isolated for at least three weeks to ensure they are healthy before allowing them to interact with the resident population.
