Foal Diarrhea Part 1: Clostridium difficile
Diarrhea is a relatively common problem in foals. It can range from very mild to fatal, and sick foals can get worse (i.e. "crash") very fast. Outbreaks of diarrhea in foals can also occur. So while most cases of foal diarrhea are mild, the implications of this condition for both the foal and the farm can be huge.
There are a variety of potential causes of diarrhea in foals. One is Clostridium difficile, a bacterium which can be found in the intestinal tract of a small percentage of healthy adult horses and foals, but which can also cause disease under certain conditions. Clostridium is a type of spore-forming bacterium - it produces spores that are able to survive for a very long time (i.e. years) in the environment, and that are resistant to most disinfectants. Most cases of C. difficile infection in foals are single, sporadic cases, but outbreaks on breeding farms can occur and can be very difficult to control. Typically such outbreaks start out with a few individual (sporadic) cases of foal diarrhea early in the foaling season, with a gradual increase in the number of cases over the following weeks to months. Often it gets to the point that all foals born later in the season develop diarrhea. You cannot tell the difference between diarrhea caused by C. difficile and that caused by other infectious agents just by examining the foal - diagnostic tests are needed to make the diagnosis (watch for an upcoming post for more information about this kind of testing).
There is little information about control measures for C. difficile infection that have been proven to work. However, our understanding of the organism and what it does in horses and other species lets us make some general recommendations:
- Only use antibiotics when it's really necessary. "Routine" use of antibiotics in foals (which some people use to try to compensate for poor management practices) is not needed, and may increase the risk of C. difficile.
- Use good general hygiene practices, particularly around the time of foaling and in areas where neonatal foals live or often are. Clostridium difficile is spread by the fecal-oral route, meaning foals swallow the C. difficile from manure contamination in their immediate environment.
- Isolate all horses (foals and adults) with diarrhea so that they are less likely to spread it to other horses.
- Do not try to treat healthy horses or foals to try to get rid of C. difficile. There's no evidence that it works and it could actually make it more likely that the horse/foal will get sick.
- Let your veterinarian run the appropriate diagnostic tests to identify the cause of diarrhea in any adult horses or foals, particularly on farms where more foals are expected to arrive. It's better to find out early with what you are dealing, in case specific preventive or early treatment measures can be used to help stop an outbreak from occuring.
- Make sure you have a good infection control program for your farm.
No vaccine for C. difficile is currently available, nor will one be available in the near future. Other techniques for preventing this disease are being evaluated but none are yet proven.
More information about Clostridium difficile can be found on the equIDblog Resources page.
