Salmonellosis in Donkeys: Infectious Diarrhea, Biosecurity, and Zoonotic Risk

Salmonellosis is an intestinal infection caused by Salmonella enterica bacteria. In equids, it is one of the most important infectious causes of diarrhea. Donkeys are managed much like horses, so vets generally apply equine infectious-disease guidance to donkey cases. Illness can range from mild fever and soft manure to sudden, severe diarrhea with dehydration, endotoxemia, and collapse.

One challenge is that not every infected donkey looks obviously ill. Some animals can carry or intermittently shed Salmonella in their manure without dramatic signs, especially during times of stress. Transport, hospitalization, surgery, diet changes, other gastrointestinal disease, and recent broad-spectrum antibiotic exposure are recognized risk factors in equids.

This condition also matters beyond the sick animal. Salmonella is zoonotic, which means people can get infected too. Children, older adults, pregnant people, and anyone who is immunocompromised should avoid contact with a donkey that has diarrhea or is suspected of shedding Salmonella until your vet says the risk is lower.

Donkeys usually become infected by swallowing Salmonella from contaminated feed, water, manure, bedding, equipment, or the environment. Direct contact with an infected or shedding equid is one route, but indirect spread is also common. Shared water troughs, feed tubs, wheelbarrows, pitchforks, tack, grooming tools, and boots can all move manure from one animal to another.

Stress plays a major role in whether exposure turns into disease. In equids, recognized triggers include transport, hospitalization, surgery, sudden feed changes, concurrent intestinal disease, and recent treatment with broad-spectrum antimicrobials. Rodents, birds, and other animals on the property may also contaminate feed or water sources.

Some donkeys may shed Salmonella intermittently after they recover, which is why outbreaks can be frustrating to control. A single normal-looking animal can still contaminate stalls, paddocks, trailers, and handling areas. That is why your vet may focus as much on biosecurity and manure management as on the donkey's medical treatment.

Diagnosis starts with your vet's exam and history. They will ask about fever, diarrhea, transport, recent hospitalization, diet changes, antibiotic use, new arrivals, and whether other equids on the property are sick. Bloodwork often helps assess dehydration, inflammation, low white blood cell counts, protein loss, electrolyte problems, and the overall severity of illness.

To confirm Salmonella, your vet may submit fecal culture, PCR, or both. Repeated fecal samples are often needed because equids can shed the bacteria intermittently, and a single negative test does not rule it out. Equine guidance commonly uses serial testing, and AAEP biosecurity recommendations note that even five negative fecal cultures do not absolutely prove an animal is free of shedding.

Your vet may also test for other causes of diarrhea, because several conditions can look similar early on. Depending on the case, that can include fecal parasite testing, bloodwork, abdominal ultrasound, and targeted testing for other infectious enteric diseases. If there is concern about a property-level outbreak, your vet may recommend testing the environment, feed, water, or manure-handling areas as part of the investigation.

Prevention starts with biosecurity that works in real life. Isolate any donkey with fever or diarrhea right away. Use dedicated halters, lead ropes, buckets, muck tools, and boots for the isolation area. Clean visible manure first, then disinfect. Avoid pressure washers or hoses that can aerosolize contaminated material and spread Salmonella to nearby stalls, people, or animals.

Good feed and water hygiene also matter. Keep hay and grain protected from rodents and birds, clean troughs regularly, and do not let donkeys share contaminated water or feed tubs. Quarantine new arrivals for about 3 weeks when possible, monitor temperatures during that period, and avoid unnecessary stress from abrupt diet changes, overcrowding, or frequent movement.

Work with your vet on a farm-specific plan if you have multiple equids, recent diarrhea cases, or animals returning from hospitals or events. AAEP guidance for equids notes that previously infected animals may need 30 days of isolation and repeated negative fecal cultures before rejoining the general population. There is no widely validated commercial Salmonella vaccine for routine equine outbreak prevention, so practical sanitation, isolation, and manure control remain the main tools.