The oral cavity of any animal is a complex environment, often inhabited by a diverse microbiomes. While the oral microbiota functions to maintain the health of the oral cavity, many of the resident microbes have been reported to be opportunistic pathogens. Stomatitis, also known as ‘mouth rot’, is usually secondary to stress or trauma to the oral mucous membrane of the oral cavity, and is a primary cause of anorexia and lethargy (9). Many microbials have been reported to cause stomatitis in reptiles. Stomatitis is a common condition reported in all reptiles and is often associated with opportunistic infections with common microorganisms in an immunocompromised animal. Pathogens reported to be found in stomatitis include bacteria such as Pseudomonas spp. and Aeromonas spp. or viruses such as Herpesvirus spp., and Ranavirus spp.

The veiled chameleon (Chamaeleo calyptratus) is a brightly coloured species of chameleon, native to the Arabian Peninsula. Lifespan is around 5 years for females, and 8 years for males. Naturally an arboreal animal, typical husbandry for veiled chameleons requires plant material and vines to climb on, temperatures ranging from 21°C to 35°C and several mists of water a day (7). Although chameleons are exotic animals in South Korea, they are increasingly being kept as pets. This case is expected to help in the diagnosis and treatment of stomatitis in chameleons.

A 4-year-old female veiled chameleon (Chamaeleo calyptratus) was presented with anorexia and open-mouth breathing. Her husbandry was adequately managed and included a mealworm diet with added supplements, ultraviolet B light, and separate temperature zones. No breeding history was available. On physical examination, the patient was severely dehydrated, and the oral mucous membranes were sticky (Fig. 1A, B) with mild petechiae present. Body weight was 173 g. An X-ray was performed, and calcification of the trachea was observed (Fig. 1C).

Figure 1. Clinical presentation of sticky mucous in oral cavity. Note the severe petechia on oral mucosal membrane (A, lateral view; B, fontal view of the oral). Increased opacity of the trachea is observed on X-ray (C). Oral cavity swab smear cytology (Diff-Quik stain) showed the hypha of fugus (D). The scale bar is 100 µm.

Treatment was prescribed in accordance to symptoms, included oral and nebulized medication. Enrofloxacin, doxycycline, famotidine, metoclopramide, and metronidazole were prescribed per oral to treat oral mucous membrane inflammation in accordance with Carpenter’s exotic animal formulary, 5th edition. Nebulization medication was also prescribed twice a day for respiratory symptom relief, containing 50 mg of amikacin, 200 mg of N-acetylcysteine, 250 mg of aminophylline, and normal saline filled up to 10 mL.

The patient’s initial response to treatment was positive: appetite returned, and weight increased. At the time of the second visit, mucous membrane was still congested and covered in sticky fluid, and subsequently an oral swab was obtained. The swab was rolled on a slide glass, fixed then stained with diff-quik, and revealed severe bacterial overgrowth and some fungal hyphae. Culture on Sabouraud dextrose agar (SDA) medium produced white colonies (Fig. 1D) with characteristic banana-shaped conidial structures and hyphae with septation and angular branching (Fig. 2). Following the discovery of mycotic infection, Amphotericin B 10mg was added to the 10mL nebulization solution.

Figure 2. Fungal growth on SDA medium (A) and photomicrograph of cultured fungi (Diff-Quik stain) (B). Note the white fluffy colonies (A) and the banana-shaped macroconidia and acute-angled hyphae (B). The fungus is identified as F. solani by PCR. The scale bar is 100 µm.

Bacterial and fungal agents were cultured and then identified by PCR. Conserved regions of 16s rRNA gene for the bacterial pathogen were amplified using primers 27F and 1942R. The amplified sequence was one hundred percent in alignment along over 1,300 base pairs with many strains of Pseudomonas aeruginosa (GenBank accession number MW664009) sequences using the Basic Local Alignment Search Tool (NCBI, Bethesda, MD, USA), which are common pathogens found in cases of stomatitis. Primers ITS1 and ITS4 were used for mycotic analysis. These primers have been described to adequately amplify the 5.8S-coding sequence of a wide range of fungal targets. The sequence amplified (GenBank accession number MW485482) showed 100% per identity with Fusarium solani, a mycotic pathogen commonly found in leaves and dirt. Common viral agents known to cause stomatitis, including Herpesvirus spp. and Ranavirus spp., were tested using the oral swabs with previously described primers (nested PCR primers DFA, ILK and KG1 for first round, TGV and IYG for second round for Herpes spp. amplification, and a single pair of PCR primers OL MCP4, OL MCP2 for Ranavirus spp.) (11,13), but were not detected. However, despite regaining appetite and gaining weight, the patient expired on day 10 of treatment.

The oral cavity of any animal is a complex environment, often inhabited by a wide range of microbiomes. While the oral microbiota functions to maintain the health of the oral cavity, many of the resident microbials have been reported to be opportunistic pathogens. Stomatitis is usually secondary to stress or trauma on the mucous membrane of the oral cavity, and is a primary cause of anorexia and lethargy (9). Many microbials have been reported to cause stomatitis in reptiles. Opportunistic agents, such as Pseudomonas spp. and Aeromonas spp., have been described as the causative agents of such conditions in reptiles that have a history of oral trauma or stress. Pathogenic agents commonly identified in reptilian stomatitis include viral agents (Herpesvirus spp., Ranavirus spp.) and bacterial agents (Pseudomonas spp., Aeromonas spp.) (11,13). Clinically, F. solani has been previously reported to cause mycoses in humans, of which infections are usually linked to dermatitis, ophthalmitis in immunocompetent patients (2,14). F. solani comprises half of human fusarium infections, claimed to be responsible for most systemic and corneal infections (10). It is also notorious for being the most resistant to drugs within the Fusarium group (1). In reptiles, shell erosions post trauma and egg mycosis in sea turtles (4,6), and a number of systemic infections has been reported in snakes and crocodiles (3,8). The systemic infection report in crocodiles described lesions in the lungs and liver (3). However, this is the first case of F. solani infection observed in reptilian stomatitis.

The patient of this case presented not only stomatitis but also respiratory symptoms and the calcification of the trachea. While mycotic infections in the respiratory system are not rare in other animal species, it is an uncommon cause in captive reptiles (12). Stomatitis, which can be classified as an upper alimentary tract disease, is rarely indicated to develop into respiratory conditions. As a novel infection, the pathology of F. solani in the alimentary or respiratory tracts of lizards is widely unknown.

A rare case of Fusarium species induced pneumonia was reported in a 68-year-old woman (5). The report included descriptions of nodules and masses in the thoracic imagery, resembling Aspergillus pneumonia. However, our case did not present significant findings in the lung tissues, which may indicate that the primary infection began in the oral cavity and spread to the upper respiratory tract. This suggests the possibility that a F. solani infection in the oral cavity may infiltrate the epiglottis and progress into the respiratory system. However, the exact cause of death was unidentified, as animal owner did not agree to necropsy.

While stomatitis in captive reptiles is regularly presented to veterinarians, mycotic agents are not usually investigated extensively. This was also the case of this report, which led to the lack of anti-mycotic drugs in the first prescription. The possibility of novel pathogen infection in reptilian stomatitis and subsequent respiratory syndrome must not be overlooked. The clinician must always consider oral swab cytology, tracheal wash culture, and molecular diagnostics when they encounter stomatitis accompanied by respiratory symptoms.

The typical reptile husbandry setup is warm and humid, and it is often ill-aerated in the average home. These conditions are also optimal for the growth of various species of fungi. While stomatitis is a common condition in reptiles, each case may occur under different circumstances. Different pathogens may also result in variable pathological progress, such as the spread to the respiratory system. Although some pathogens are frequently reported in stomatitis cases, this case demonstrates the necessity for clinicians to investigate a wide array of causes in order to make a well-grounded diagnosis.

The authors have no conflicting interests.