Reptiles (turtles, snakes, iguanas and geckos) often carry bacteria that can make humans sick. These bacterial diseases are important to understand as part of a One Health approach.
Abscesses occur when bacteria settle in a local area and form a hard collection of pus. They are often accompanied by blood infection and must be surgically opened and antibiotics given.
Respiratory Infections
Reptiles can develop bacterial infections, abscesses (swellings filled with pus), and parasitic infections. These diseases are usually due to poor environmental conditions and/or stress. Affected reptiles may have trouble breathing and develop open-mouth wounds or discharge from the nose. Septicemia (widespread infection in the blood) is also common and often fatal. Signs of septicemia include a low appetite, lack of energy, swollen limbs or jaw bones and cloacal prolapse.
A fungus that causes disease of the skin and respiratory tract is a frequent cause of illness in reptiles. Some fungal infections are fatal. Other fungi that can cause disease in reptiles are gastrointestinal infections and parasite infestations of internal organs.
Gout (a form of arthritis) can affect reptiles, especially frogs, turtles, and tortoises. It occurs when there is a buildup of uric acid in the body. It is often diagnosed by radiographs and can be classified as either visceral gout, which affects the organs, or articular gout, which affects the joints. Treatment involves medications to reduce uric acid levels and to help the animal move around.
Paramyxovirus Infections
Infections of the respiratory tract are common in reptiles, and can be bacterial, viral, parasitic, fungal, or a combination. Often, these infections are life-threatening due to their severity. The most common cause of respiratory infections in reptiles is suboptimal living conditions, which stress the animal and prevent it from fighting infection. Young, old, or immunocompromised reptiles are particularly at risk for acquiring these infections.
Several viruses have been isolated from herpetoid and chelonid species of reptiles, including ranaviruses in chameleons, herpesviruses in tortoises, and paramyxoviruses in snakes. These viruses are enveloped RNA viruses with genome RNA encapsidated by a ribonucleocapsid protein (RNP) and a lipid envelope.
The RNP proteins contain an N-linked carbohydrate, and the genomic RNA has an average of 10 residues per nucleotide. On a molecular level, the paramyxovirus P gene encodes from three to seven proteins. These proteins are produced by two distinct transcription mechanisms: internal initiation and insertion of nontemplated G residues in the RNA. The virus has a narrow host range in nature, but has been shown to infect a wider variety of cells in culture.
Secondary Renal Hyperparathyroidism
Metabolic bone diseases (MBDs) of various origins are the most common causes of lameness, skeletal and spinal abnormalities in reptile patients. These disorders can manifest as fibrous osteodystrophy, osteomalacia, osteoporosis or osteosclerosis. Bone lesions are often swollen, misshapen or painful and may be symmetrical or asymmetrical. Other symptoms include drooling, weight loss, poor appetite or vomiting.
Renal secondary hyperparathyroidism can result from a dietary imbalance that is high in calcium or vitamin D but low in phosphorus or from chronic renal disease that leads to elevated parathyroid hormone (PTH) secretion. The resulting syndrome is known as rickets or renal osteodystrophy and has a variable prognosis (5).
Secondary hyperparathyroidism develops early in the course of CKD and becomes more prominent as kidney function declines. A calcimimetic drug, such as cinacalcet HCl (Sensipar), can be used to prevent and treat this disorder. The drug competes with phosphorus for intestinal absorption sites. For this reason, the use of oral calcium is also recommended to help reduce the absorption of phosphorus. The best long term treatment is to manage the underlying condition that is causing the hyperparathyroidism by diet modification, refeeding with a diet rich in calcium and vitamin D and by using the calcimimetic drug.
Cloaca Infections
The digestive, urinary, and reproductive tracts combine to form the cloaca in reptiles. Any condition that disrupts the normal protective barriers of cloacal tissue can lead to infection (cloacitis). This infection may spread throughout the body, and if untreated, it leads to death.
Various coccidial organisms cause disease in snakes and other reptiles with suppressed immune systems. Many of these infections can be controlled with intensive supportive care, including a regimen of antimicrobial medications. Intensive treatment usually resolves the symptomatology, but the underlying causes must be addressed or the condition will return.
Reptiles can also suffer from fungal skin and respiratory infections. These infections are commonly associated with poor husbandry conditions, unfavorable environmental temperatures and humidity, concurrent diseases, malnutrition, and ectoparasites. Affected reptiles exhibit loss of appetite and weight, respiratory distress, open-mouth breathing, mucus or bloody diarrhea, and often die if the condition is not treated promptly. Septicemia, a systemic illness that affects multiple organs, is common in severe or protracted cases. Aeromonas and Pseudomonas spp are the most commonly isolated microorganisms.
Abscesses
Abscesses form in response to bacterial infections and may be found throughout the body of reptiles. They appear as swollen areas of the skin that may ooze a yellowish liquid and eventually become crusty. The bacteria that cause these infections are opportunistic commensals of the animal’s gastrointestinal tract or environment and can be spread by parasites as well. Septicemia can occur in severe or protracted cases of infection.
Surgical debridement, repeated irrigation with antiseptics and systemic antibiotics are usually indicated for treatment. The antibiotic of choice is generally a quinolone such as enrofloxacin, which decreases blood flow to the abscess and allows it to consolidate, thus making it easier to remove.
Reptiles with abscesses that recur frequently should be evaluated for predisposing factors such as poor husbandry, metabolic diseases, nutritional deficiencies and stressors in their environment. A thorough history and physical examination should be performed to evaluate appetite as anorexia is common in reptiles with abscesses. Failure to stimulate appetite is a strong indicator of disease and should be thoroughly investigated with diagnostic tests such as radiographs, bacteriology, serologic testing and biochemical analyses.