Diarrhoea in Guinea Pigs

Diarrhoea is the increased frequency of passing faeces. It is usually, but not always, associated with more watery stools. It is often smelly, sticky and can leave your guinea pig’s back end messy, unlike normal formed stools.

Depending on the specific cause, your guinea pig may also have other symptoms, such as blood from the back end, a sore bottom, going off their food or water, weight loss, dullness or depression, enlarged lymph nodes, poor fur quality, pain with a hunched-over appearance, or a bloated belly.

There are many causes of diarrhoea and this list is by no means exhaustive – some of the most common are:

Problems with the diet. Any dietary issue can lead to diarrhoea. Low fibre in particular often leads to diarrhoea, especially in guinea pigs fed mostly on ‘muesli’ and not an appropriate diet of mainly hay or grass. Diarrhoea can also be caused by poor quality or toxic foods, such as those stored incorrectly or those out of date. Sometimes even appropriate food can cause diarrhoea if introduced too fast – make changes to a guinea pig’s diet slowly.

Bacterial or viral infections. Infections occur most frequently in young animals but can occur at any age. Common agents include E. coli, Salmonella, Clostridium, Campylobacter, coronavirus and rotavirus and more. Infections vary from just causing mild diarrhoea in an otherwise healthy guinea pig, to severe life-threatening infections. Most can easily be transmitted to other guinea pigs.

Parasites. Just like in dogs and cats, parasites are a potential cause of diarrhoea in young guinea pigs. The three main groups are tapeworms, roundworms, and protozoan parasites like Cryptosporidium. These tend to cause slow chronic wasting, or a failure to gain weight. They are most common in large groups of guinea pigs with poor environmental cleanliness.

Dysbiosis. Dysbiosis describes where the normal bacteria population within the gut is disrupted, resulting in reduced absorption of nutrients and water from food, causing diarrhoea. There are many causes of dysbiosis, ranging from stress or infection, to blockages or toxicities, poor diet and starvation. Dysbiosis can also be caused by the use of antibiotics - if a vet prescribes antibiotics for an infection in your guinea pig, there is a chance it will lead to diarrhoea due to destruction of their gut flora. If this occurs, seek veterinary advice before giving any more antibiotics.

Vitamin C deficiency. Guinea pigs with poor diets are susceptible to low vitamin C levels (scurvy, or hypovitaminosis C). As well as diarrhoea, hypovitaminosis C can lead to weakness, anorexia, swollen joints and lameness, skin damage, excessive bleeding and poor coat, and death if left untreated. Another reason why a proper diet is important.

Cancer. Intestinal cancers in guinea pigs are rare, but have been reported to sometimes occur and cause diarrhoea.

Most vets will approach the diagnosis of diarrhoea by starting with history taking. This involves asking you questions about the diarrhoea itself, how long it has lasted, its frequency, its severity, colour, consistency, etc. Next we ask how your guinea pig is – are they well or sick, eating and drinking well, still wanting to interact. Husbandry is also important – what is your guinea pig’s diet, habitat, bedding, cleaning schedule and so on. We will also ask if any other guinea pigs are sick, if you have used any medications at home, and more.

The next step is a physical exam of your guinea pig. This is a nose to tail examination to identify symptoms, as well as narrow the potential causes of diarrhoea. With diarrhoea, there will be a particular focus on looking at your guinea pig’s demeanour, hydration status, abdomen palpation, temperature, gut sounds, messiness on the back end, weight and body condition score. From here, there are many different routes to take next depending on the specific presentation. Sometimes, just history and a clinical exam is enough to start treatment.

Analysing the faeces can be important, to look for signs of parasites like eggs. We can also culture any bacteria in the faeces to identify pathogenic bacteria. More specific tests like PCR or ELISA can be performed to identify bacteria, viruses or parasites. If we are concerned about the urine, this can be analysed in a similar way.

Blood testing can sometimes be performed in guinea pigs. General blood screens can identify non-specific abnormalities, such as dehydration, anaemia or problems with various organs. More specific blood tests may again identify infectious agents.

Imaging is a good way to look within the body itself. Radiography (X-rays) is most commonly performed, to look for signs of organ enlargement, shrinking, bloat or even masses. However, in the abdomen, a lot of detail is lost due to overlapping. Ultrasound can be more precise in looking at the structure of organs, but can be difficult to do in small guinea pigs. Advanced imaging like CT or MRI is possible but it is expensive and uncommon.

Finally, there is the option for a post-mortem in those unfortunate cases where a guinea pig passes away or is euthanased due to severe diarrhoea. Looking at the body internally, and taking samples, is often the best way to definitively diagnose hidden problems. Of course, it will not help the deceased guinea pig, but some owners may wish to have an answer, or identify a disease that could harm their other guinea pigs.

Treatment will again depend on the specific cause of the diarrhoea. Non-specific treatment may include pain relief, fluid therapy to restore hydration and electrolytes, probiotics and nursing care for very sick guinea pigs. Those with bacterial infections may respond to antibiotics, while those infected with parasites can be helped with anti-parasiticides. Dysbiosis can be helped with probiotics or even transfaunation where faeces is harvested from a healthy guinea pig and fed to the sick guinea pig to restore their healthy bacterial population. Issues related to diet can be corrected slowly by introducing an appropriate diet.

Preventing diarrhoea often begins at home. Ensure your guinea pig has an appropriate diet of mostly hay or grass, some suitable pellets, and scarce treats. Regular cleaning of their hutch, water and food bowls is important to prevent parasitic or bacterial infections. Always remove uneaten food too to prevent it rotting and spreading bacteria.

Introducing a new guinea pig can risk spreading disease, so ensure they come from a reputable source and consider a brief quarantine period. Minimise stress by keeping them in temperate quiet parts of the house – avoid moving their habitat regularly. Regular check-ups with a vet can also help identify husbandry issues early before they cause diarrhoea.