The bacteria Salmonella consist of many different varieties. Regions, animal hosts and environmental factors contribute to the varying strains but regardless of which strains are present an infection resulting from any salmonella is something that needs prompt medical attention.
Salmonella is most often passed to the horse from birds, rodents and infected horses. This hardy bacterium grows in an anaerobic environment and can last for close to a year. Freezing does not kill it but a dry and sunlit habitat can help to eliminate it. Because the usual transmission occurs from fecal to oral contamination keeping a clean environment can help reduce the risk of infection. Keeping water sources clean of bird droppings, all areas free of rodents and stalls and paddocks free of manure can all help to battle salmonella from taking control of your barn and yards.
Most horses that succumb to salmonella do so because of physical or environmental stress. Horses kept in over-crowded paddock areas, or that are trailered for long periods of time without a break, those that are suffering from other illnesses or immune deficiencies and foals are those animals that are most susceptible to an acute attack of salmonellosis.
Once infected horses display a wide range of symptoms. Colitis and diarrhea that is fetid, watery and green or black are both very common. Colic sometimes accompanies the diarrhea and in milder cases you might see just colic. Fevers, cardio-vascular shock, dehydration and some changes in the effected animalsí blood counts are all common symptoms. In severe cases secondary issues can arise. Laminitis, secondary fungal pneumonia, kidney failure and a host of other very serious side effects can all occur while fighting a salmonella infection.
A positive fecal culture (for salmonella) will confirm diagnosis. Once confirmed treatment is supportive until the body rids itself of the bacteria. I.V. fluids, electrolytes and other parenteral (not in the stomach) feeding will help maintain the horse throughout the infection. Treating horses with anti-biotics is currently in debate and not generally recommended. Once the diarrhea ends most horses recover without added consequence. Those that present with diarrhea for 10 days or more are in danger of too much damage to their intestinal mucosa to recover completely and may in fact never recover.
Ridding the environment of all potentially infected fecal material is paramount to ending any spread of contamination or re-infection. Organic material must be removed and all items that come in contact with infected animals and feces should be disinfected. Isolation of the infected animal(s) until the results of at least five consecutive negative cultures are obtained is also recommended.
Vaccines against Salmonella are available but the efficacy is undertermined.
Salmonella is common in the environment but with proper hygiene can be kept at bay. Any animal that has been under stress due to any reason and that then displays diarrhea should be attended to promptly to avoid serious consequences.