Infectious stomatitis in crocodilians (mouth rot)
Infectious stomatitis, often called mouth rot, is a common infection in Nile crocodiles, particularly in farms or captive settings. It affects the mouth lining and sometimes the skin of the snout. Opportunistic bacteria, normally found in t...
What is it?
Infectious stomatitis, often called mouth rot, is a common infection in Nile crocodiles, particularly in farms or captive settings. It affects the mouth lining and sometimes the skin of the snout. Opportunistic bacteria, normally found in the animal's environment or mouth, take advantage of a weakened immune system to multiply and create lesions. Without treatment, the disease can worsen and impair the animal's ability to feed normally.
Key point
Untreated infectious stomatitis can progress to bone infection or septicemia, which may be life-threatening in the Nile crocodile.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Early signs are often subtle: a small whitish or yellowish patch on the gum, tongue, or palate. Over time, these lesions develop into ulcers, sometimes covered with a foul-smelling caseous deposit resembling cheese. The animal may drool excessively, refuse to eat, or have difficulty eating. Bad breath is common. In advanced cases, the infection can spread to the deep tissues of the jaw, causing visible swelling or even deformity. Affected animals often become lethargic and lose weight gradually.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The disease is caused by opportunistic bacteria, particularly Aeromonas and Pseudomonas species or other bacteria naturally present in the water and soil of enclosures. These microorganisms typically take hold following a minor mouth wound—from bites between animals, contact with wire mesh or abrasive structures, or feeding on prey with sharp bones or spines. A weakened immune system, often linked to environmental stress, facilitates infection.
Dirty or poorly changed basin water promotes bacterial growth. Water or air temperatures unsuitable for the crocodile's needs impair its immune system. Overcrowding in farm pools increases bite wounds between animals. Chronic stress from transport, handling, or an inadequate environment weakens the animal. Poor nutrition, particularly vitamin deficiencies, reduces natural defenses. Young animals and those already weakened by another disease are more vulnerable.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The exotic animal veterinarian examines the animal's mouth, typically under restraint or light sedation due to the risks associated with handling a crocodile.
A sample from the lesions may be taken to precisely identify the bacteria responsible and guide treatment choices.
Additional tests (radiographs) may be necessary if bone involvement of the jaw is suspected.
Treatment
Treatment mainly relies on antibiotics tailored to the identified microorganism, administered as determined by the veterinarian.
Gentle local cleaning of lesions with mild antiseptics may support the care plan.
Improvement of husbandry conditions (water quality, temperature, diet) is essential to support healing.
Nutritional support may be offered if the animal stops eating normally.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Maintaining clean, well-filtered water in the enclosure is the most effective preventive measure.
It is recommended to limit the number of animals per enclosure to reduce fighting and injuries.
Temperature suitable for the species must be maintained consistently.
Balanced, species-appropriate diet including necessary nutritional components strengthens the animal's natural defenses.
Regular observation of the animals' mouths allows early detection of lesions before they worsen.
Isolating any injured animal prevents secondary contamination.
Possible complications
Without treatment, the infection may spread to the jaw bones, causing osteomyelitis (bone infection) that is difficult to treat.
Prolonged inability to feed leads to severe weight loss and general weakness.
In severe cases, the infection can become generalized throughout the body (septicemia) and threaten the animal's life.
When to see a veterinarian
Persistent white or yellowish plaques in the mouth
Excessive or abnormal salivation
Refusal to eat for several days
Marked bad breath
Visible swelling of the jaw or snout
Progressive weight loss in the animal
Prognosis
The prognosis is favourable if the disease is caught early and husbandry conditions are corrected. However, if the infection has spread to the jawbone or has become systemic, the prognosis becomes much more guarded, even with appropriate treatment.
Frequently asked questions
Is infectious stomatitis in crocodiles contagious to humans?
No, it is not a recognized zoonotic disease. However, any handling of a sick crocodile must be done with hygiene precautions, as with any contact with a wild or sick animal.
Can you treat crocodile rot mouth yourself?
No. This disease requires a precise veterinary diagnosis and safe handling of the animal. Self-treatment is dangerous, both for the animal and for the person attempting to handle it.
Does this disease affect only captive crocodiles?
It is mainly documented in farmed and captive populations, where animal density and water quality are significant risk factors. It remains possible, but less frequent, in wild animals.
How long does the treatment last?
The duration varies depending on the severity of the lesions and the response to treatment. The veterinarian regularly assesses the progression of oral lesions to adjust the management plan.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
CDC — Centers for Disease Control and Prevention
Content reviewed by the TunisieVet editorial team · Updated 28 August 2026
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