A variety of Salmonella species are commonly present in amphibian digestive tracts. Many are easily transmitted to humans and can cause severe health problems, especially among the young, elderly and immune-compromised. It is essential that you discuss with your family doctor the best methods of avoiding the transference of Salmonella.
Otherwise healthy amphibians may harbor Salmonella without external symptoms. Animals suffering from an infection will usually cease feeding and become lethargic. Your veterinarian can diagnose Salmonella via blood tests (often the animal will be anemic) and fecal samples. Gentamicin and other antibiotics, methylene blue and acriflavine have proven useful against Salmonella.
This gram-negative bacterium causes many of the most commonly seen infections in captive amphibians. Usually diagnosed as “red leg” or “septicemia”, Aeromonas outbreaks cause hemorrhages leading to patches of red skin, often on the underside of the legs and abdomen. In advanced cases, the skin sloughs off, leaving large, open sores. Definite diagnosis is made by a culture of blood samples.
Aeromonas is extremely contagious and transmitted by contact between animals or with the water or substrate in which infected animals were held. Be sure to wash your hands thoroughly after handling sick amphibians and to use separate nets and other tools for each cage. A number of medications are useful in treating Aeromonas infections, but only if the condition is caught early on.
If you suspect Aeromonas, a first step might be to lower the temperature at which your pet is held. Among temperate amphibian species (i.e. leopard frogs, Rana pipiens), temperatures of 39 to 41 Fahrenheit have been used to successfully treat infected animals.
Many other ailments that commonly afflict amphibians are caused by bacterial infection. Those caused by Micobacteria are particularly difficult to treat, while Chlamydia infections usually respond well to medications such as Oxytetracycline. A. hydrophila is usually implicated it gas bubble disease, a complicated phenomenon that originates from environmental conditions. These and related microorganisms will be discussed in a future article.
Fungi are particularly adept at taking advantage of conditions, such as an unsanitary terrarium or depressed immune system, which might predispose an amphibian to attack. Fungal infections often occur secondarily to another health problem, and their presence should be suspected whatever a frog or salamander becomes ill.
At least 20 species of fungi in the genus Saprolegnia have been shown to cause illness in fish and aquatic amphibians. Symptoms are cottony growths on the skin, weight loss, regurgitation, difficulty breathing and, eventually, ulcerations that resemble “red leg” (see above). Saprolegnia is nearly always present in the aquarium, and usually becomes established on amphibians when the mucous covering is removed from the skin (one reason frogs and salamanders should be held in soft nets or with wet hands only).
Free-living amphibians are host to a wide variety of parasites, often with little ill effect. However, when stressed by a poor diet or improper environmental conditions in captivity, the immune system may weaken and open the way to a more severe infestation. Also, due to the close confines of captivity, parasites have a much easier time infecting, or re-infecting, animals than they do in the wild.
Routine fecal exams are very important in identifying and controlling parasites. Many are resistant to medication while in their egg or spore stage, and therefore you must be careful to follow your veterinarian’s recommendations as to re-treatment (often a two-week interval will be suggested). Some parasites, such as Oodinium pillularia (which also causes “velvet disease” in fish), Charchesium, and Vorticella respond well to baths in a 0.6 percent sodium chloride solution, while others, such as Trypanosoma diemictyli, nearly always result in fatalities.
Vitamin and Mineral Imbalances and Environmental Factors
Amphibians are extremely sensitive to pesticides, disinfectants, and a wide variety of chemicals that are very common in our environment and even in the pipes that supply water to our homes. Also, as with ourselves and all captive animals, good nutrition provides the foundation for good health. I will address these topics in a later article. For now, you may wish to refer to an article I wrote earlier and posted on this blog – “Providing a Balanced Diet to Captive Reptiles and Amphibians”.
I have been fortunate in having had the opportunity to experiment with a number of medications and environmental approaches in my quest to learn more about maintaining amphibians in good health. In a few cases, I have met with some success. Doing so, despite my lack of medical training, has made me realize the value of observation and reasonable experimentation in this area. I’ll write more about this in my next article, but for now please remember that this area offers great opportunities for interested hobbyists.
A variety of articles on amphibian and reptile health, written by one of this field’s leading veterinarians, are posted at:http://www.azeah.com/