Treatment of Sores and Wounds in Caudates
Heather Björnebo, DVM
Cutaneous ulcers, a.k.a. sores, are one of the most common ailments seen in captive caudates. These sores often start small but grow rapidly, resulting in morbidity and mortality. These delicate animals can still be saved by addressing any husbandry issues and implementing appropriate medical treatment early.
Etiology. The vast majority of animals found in stores are wild caught and endure sub-par care on the way to store shelves. An unwary shopper may purchase their new pet without noticing wounds or "stress sores," finding themselves with a very seriously ill newt or salamander. A seemingly healthy individual may deteriorate even with adequate husbandry due to the poor conditions experienced in shipping and at the store. Regardless of the story, the cause was inadequate care at some point. A sick animal presents the owner with the challenge of evaluating every aspect of husbandry. Researching and correcting the animal's care becomes of utmost importance. No matter how aggressive the treatment nor the amount of medications, no animal can be expected to make a recovery in inadequate conditions. Some commonly found husbandry problems include temperatures that are too warm, poor sanitation, poor water quality, and mixing of species. Inappropriate tankmates can result in injury or introduction of disease.
Infectious agents. Bacterial pathogens are the most common organisms isolated from infected wounds in amphibians. Most of these are gram-negative species, and the most common isolates include Aeromonas, Pseudomonas, Proteus, Serratia, E. coli, Klebsiella, and Citrobacter. Often it is difficult to distinguish normal flora from pathogens since many of these organisms are found on healthy individuals. Fungal pathogens are also seen on rare occasions.
Quarantine. Ill animals are often contagious to other animals within their enclosure. In addition, most caudates produce secretions and toxins that may affect their healthier tank mates. A quarantine enclosure should ALWAYS be used to isolate the ill animal. The enclosure should be simple and easy to clean, while remaining appropriate for the animal being housed. In most cases, the quarantine enclosure should be a very simplified version of the regular cage. It isn't a bad idea to have the quarantine located in a different room than the main enclosure. A cool, dark location may help to reduce the stress on the sick individual. Animals remain in quarantine minimally until resolution of clinical signs; however it is best that animals remain in quarantine least 30 to 60 days after recovery to monitor for recurrence.
Topical Antibiotics. Topical antibiotics may be all that is necessary for fresh, minimally contaminated wounds. For the purpose of this article a “fresh” wound will apply to those that are less than 12 to 24 hours old and arise from injury such as bites from tankmates. Several common veterinary preparations are available by prescription at relatively low cost. Ointments such as bacitracin 2% (Bactoderm, Pfizer) or mupirocin 2% may be used. However, some research suggests that ointments may delay wound healing and closure. Silver sulfadiazine (Silvadene) cream is also very popular and may actually encourage more rapid healing. Over the counter triple antibiotics have also been used with varying success. Avoid ointments or creams containing local anesthetic pain killers, such as pramoxine, benzocaine, etc., as these substances can be extremely toxic to amphibians.
Systemic antibiotics. Any wound greater than 12 to 24 hours old or contaminated with large amounts of material should be considered infected. Other signs that a wound is infected include discharge, increase in wound size and/or depth, or fuzzy, white growth. When faced with an infected wound, more aggressive treatment with systemic antibiotics (versus topical ointments or creams) is definitely warranted. Seek advise from a veterinarian versed in the special medical needs of amphibians. They will be able to prescribe appropriate antibiotics and treatment regimens for your pet. Often, injectable antibiotics can be used topically, either as a medicated bath or by merely dripping a calculated dosage onto the animal's back. (Due to their highly permeable skin, amphibians can absorb medication this way.) Commonly-used antibiotics include enrofloxacin (Baytril, Bayer) or amikacin. Your veterinarian will be able to take samples of the site and run testing to determine the antibiotic to best treat the infection.
While professional veterinary advice is recommended, some may not have access to a veterinarian knowledgeable enough about amphibian medicine. In these incidences many keepers will use medications commonly available over the counter for aquarium fish (kanamycin, tetracycline, Maracyn, Maracyn 2, or nitrofurazone). It is imperative to follow the manufacturer's directions carefully. However, these medications are only beneficial for aquatic animals. For terrestrial or semi-aquatic animals medicated baths may be prepared using these medications in high concentrations and allowing the animal to soak for 15 minutes daily.
Limitations of antibiotics. It should be mentioned that antibiotics are not a save-all. Antibiotic application itself can result in extreme stress on an already stressed animal. In some instances this can even result in death. Some terrestrial animals, such as Tylototriton spp., do not handle medicated baths well and may even begin to vomit and go into shock. So in summary, treatment must take into account the stress level and disposition of the patient.
The common perception is that antibiotics are all relatively safe; they are not. Antibiotic means "against-life." Even with appropriate dosage and application, adverse reactions do occur. It is unfortunate that very little research has been done to date on the safe level of antibiotics for each individual species. If systemic antibiotics are going to be used, I again strongly recommend consulting a veterinarian experienced in amphibian medicine.
Topical Treatments. The following topical treatments have all been used with caudates as either an adjunct to antibiotics or in addition to the method discussed below. Unfortunately, little information is available on these products and their effectiveness in treatment – use with caution.
- Hydrogen peroxide. Dab infected area with a Q-tip soaked in 1.5% hydrogen peroxide (generally a 1:1 dilution of the solution sold in pharmacies). Rinse well with clean water. Do not apply to large areas of skin, as it does cause some damage to healthy tissues. Hydrogen peroxide is effective mainly on anaerobic bacteria. Thus is it more likely to be beneficial for deep wounds, not surface wounds or ulcers.
- Iodine solution. Create a dilute solution by adding ¼ tsp (1.25 ml) of 10% povidone iodine to 1 cup (300 ml) of clean water. The resultant solution resembles iced tea if diluted properly. Dab the infected area with a Q-tip soaked in diluted iodine solution. After application, be sure to dab the area dry and rinse with dechlorinated water or sterile saline. Use iodine based medications with caution and in small amounts. These must be diluted before use, as iodine is highly toxic to amphibians. DO NOT bathe the animal in these chemicals.
- Bactine (0.13% benzalconium chloride + lidocaine). See: USGS Guidelines for Handling Amphibians.
- Regular tap water. Another method utilizes cleaning with regular tap water containing chlorine. Only use your tap water if it is known to be relatively safe.
Environmental manipulation. Alternative medicine is becoming more popular not only in human medicine, but in veterinary medicine as well. Often touted as an alternative to systemic antibiotics, the method commonly referred to as “dirt quarantine” became very popular several years ago because it utilizes environmental manipulation to allow the animal to heal itself. The general premise is that changing the environment weakens the infectious organism, and then the animal's natural immune system can eliminate the infection. It was observed that caudates often will move to land or drier microhabitats when ill. The theory is that they are seeking a place dry enough to upset bacterial growth but not too dry to cause themselves harm.
Use a secure, well ventilated container for a cage; the commonly available “Kritter Keeper” works well. Substrate should be plain backyard soil or garden center organic top soil (not potting soil). Moisten the soil. The soil should be moist enough that it can be packed and formed, like dry clay not mud. Pack it into the bottom of the cage to be used to a depth of 2 to 4 inches. As the dirt dries, moisture will need to be added to keep the animal from dehydrating. A moisture gradient should be created by spraying/misting water into only one corner; this way one side is very wet, and the other is drier. Do not make mud. You should also provide hiding places throughout the enclosure, and the animal will be able to choose the moisture level they feel most comfortable with.
Terrestrial and semi-aquatic species take well to this regimen. However, this type of system should be used with caution when it comes to species that loose water rapidly, such as paddletails (Pachytriton spp.). Some of the more aquatic species such as ribbed newts (Pleurodeles waltl) will heal well with this method. Many keepers utilize topical treatments along with the quarantine and achieve success as well.
Conclusion. Whatever method is used, the most important step is to address all concerns with respect to husbandry. Without addressing underlying problems, relapse is far more likely if not guaranteed. Response to treatment is dependent not only on the methods used but on the ability of the animal to respond to treatment. Even with the best laid plans and most aggressive treatment, some animals may still fail to respond. This further emphasizes the importance of preventative care by providing the best possible environment for our slimy captive friends.
© 2001-2008 Heather Björnebo
Revised September 9, 2008