Discription: Many species of Chytrid, pronounced kit rid, fungus exist throughout the world and are an important part of the natural process of decay that recycles organic wastes. Batrachochytrium dendrobatidis is a species of Chytrid fungus that normally lives in damp soil, mud and water feeding off of decaying matter. It also thrives on the keratin in amphibian skin causing the disease called Chytridiomycosis. The belly skin may be the first area to be infected. Tadpole skin does not have keratin but they do have some around the mouth and may carry the fungus, dying from it after metamorphosis. Some species have little resistance to it and die right away but others get infected and do not show any signs of sickness yet carry and spread the disease.

Chytridiomycosis, or as it is best known, Chytrid, is a major problem across the globe causing many species to go extinct with many more to be expected. It is believed to have originated in Africa and spread to other areas of the globe through the African clawed frog, which can be a carrier without getting sick. In the 1950’s, this frog was widely used for pregnancy tests and years later it became a popular pet. The spread of the disease continues through this species as well as the Dwarf underwater frog, Pacman frogs, Whites tree frog, Bull frog and many others, some that may be carriers without showing any signs of sickness. For some frogs, it can take up to 2 or 3 months to progress to a point at which noticeable signs start to show. A trigger, such as a change in temperature or stress, will often allow the fungus to manifest itself. Cool but not real cold temperatures seem to be ideal for it to grow.

The Solution? The best thing would be a way to make all amphibians and their future offspring immune, but this is very unlikely. It would be great if a species that now only exists through captive breeding could be re-introduced back into its native habitat.

Some promising research is being done with a naturally occurring bacteria that is found on amphibian skin. The species, Janthinobacterium lividum, has been found to produce chemicals that are able to attack the fungus. These anti-Chytrid metabolites can sometimes reach levels high enough to kill it.

Other researchers are trying to selectively breed Chytrid resistant Panamanian golden frogs. They are picking out the ones with the highest levels of anti-microbial peptides in their skin in an effort to breed frogs that can fight off the infection.

Highly contagious through direct body contact as well as from the environment.

It stops reproducing at temperatures over 90°F and will die if it stays above 95°F for about 6 hours or so. Higher temps kill it faster; about ½ hr at 120°F and about 5-10 min at 140°F. Mammal body temps are too high for this fungus to infect them.

It will die if allowed to remain dry for about 6 hours.

It may stay alive in the water for about 7 weeks without a frog host to infect.

People and warm blooded animals can not catch it but can transfer it to amphibians.

It is widespread in the environment and can easily be further spread if it is not known that a frog is carrying the fungus or if a person does not know what it is.

Improper treatment and disposal of infected dead animals, water, soil, plants or the things that they have been in contact with can spread the fungus to other amphibians and into the environment with devastating results. Bleach, boil or burn everything, including waste water!

Symptoms: Other problems could cause some of the same symptoms as Chytrid so it may have to be a judgement call if testing is not done to confirm it. The most common sign is excessive shedding of the skin but not all species exhibit this, some may become slimy, gooey or milky looking instead. The skin may start flaking and/or become dry, lacking the slime layer and making them feel rough or less slippery. The color may become pale or splotchy or even darker than normal. Infected frogs often may become lethargic and lose their appetite, sometimes not moving at all, not even to right themselves when turned on their backs. Some will have a hunched over posture.

Treatment: Prevention is, of course, the best thing we can do to protect our animals and quarantine is the key. Extraordinary measures should also be taken to avoid spreading it through contaminated objects, escaped food items, splashed/dripped water or your hands, etc. If a newly acquired amphibian is a species that is known to be a carrier, prophylactic treatment may be the best course of action. It could also be wise to treat any imports just to be safe and to slow the spread of this devastating problem. In the rare case when the amphibian species can safely withstand temps around 95°F for a couple of days, this may be sufficient to wipe it out.

The quarantine period should last for at least two months, preferably three. When performing any treatment regime, it is important to return them to a disinfected hospital tank after each session is completed. Re-infection is likely to occur from a contaminated environment if this protocol is not strictly followed. Use new rubber gloves to transfer the frog for treatment and fresh new ones to transfer it back to the hospital tank each time. The hospital tank should be minimally furnished but still provide for the frogs needs. Temperature and humidity must be maintained at the appropriate levels and a substrate of some sort will be beneficial. Paper towels or Scotchbrite pads work well. Plastic plants may reduce stress by offering a place to hide. All furnishing used and everything that has been in contact with them must be sterilized and/or properly disposed of between treatment sessions and upon completion of all the treatments. A 10% bleach solution has been found to be effective to sterilize things (add 5% bleach to sterilize waste water before disposal). Be sure to rinse everything thoroughly afterwards so that no bleach odor remains. It is also helpful to allow things to dry completely before reusing them. High temperatures, especially when combined with sufficient desiccation, have been shown be effective. 5 to 10 minutes in water at 140°F will kill it. Lower temps take longer but will still work. Soil can be sterilized by being baked in an oven until the inside temp reaches near 200°F. Be sure that the soil remains moist to avoid burning. A soak for 5 to 10 minutes in a 4 to 5% warm bleach solution can be used to disinfect plants. Follow this with a 20 minute soak in clean water with extra dechlorinator added to it. Some of the plants will not survive this and it may be best to just burn or sterilize and dispose of most or all of them.

Enclosure considerations: The frogs need to be removed and treated in a sterile environment and their permanent enclosure will need to be sanitized before they can be returned to it after they are cured. This may be a difficult task but it must be done thoroughly to avoid re-infection.

Aquatic considerations: Dwarf underwater frogs will benefit from having a lower water level during treatment to allow them to more easily reach the surface to breathe.

2 tablespoons of sea salt mix per gallon of water should be added to aid in correcting the electrolyte imbalance this fungus causes. Water conditioners for tropical fish that neutralize chlorine and chloramines and produce a slime coat may be helpful to use instead of sea salt. Raising the water temp can slow its’ growth and allow some extra time to treat sick frogs, dwarf underwater frogs can easily handle temps between 83 and 86°F.

The aquarium and most accessories can be sterilized with a 10% bleach solution (use a 5% solution to avoid damaging acrylic tanks). Rinse very well. Dry them out completely and allow them to stay dry for at least 12 hours. Any non-frog tank mates such as fish, invertebrates or live plants need to be housed away from the frogs for 2 to 3 months. The plants could be properly disposed of instead. The gravel can be baked in an oven at 350 to 400°F for about an hour or so. The inner temp must reach near 200°F.

An Alternate method is to slowly raise the water temp up to around 102 to 104°F and maintain it there for about 6 hours to kill the fungus.

Keep in mind that bleach is used up as it comes into contact with organic matter and starts oxidizing. More than one application may be needed in very dirty situations.

Helpful conversions: ppm = mg per liter; 15 ppm = approx. 0.4 tbs. per US-Gal

1 ml = 1 cc; 1 ml = approx. 20 drops; 1 L = 0.26417 US-Gal; 1 US-Gal = 3.78541 L

1 tablespoon (liquid) = ½ oz = 15 ml (also = approx. 14 to 15 grams in dry weight)

Lamisil AT (1% Terbinafine Hydrochloride) athlete’s foot spray pump treatment: This is an over-the-counter preparation that has been found to be effective for treating Chytrid fungus and is safe to use on amphibians.

Use 10 sprays per 200ml of water that is about the same temperature as the hospital tank. Bathe the frog in it for 5 minutes making sure that the frog is completely covered with the mix. Repeatedly pour the solution over the frog or push it under the surface if needed, being careful not to drown it. Tree frogs can be put in a closed container and rotated to cover them with the solution. A rinse in clean (same temp) water afterward is a good idea, especially with delicate species. Repeat the process each day for 10 days using a fresh mix each time, returning them to a pre-sterilized hospital tank after each treatment.

Benzalkonium Chloride (alkyl dimethyl benzyl ammonium chloride) Treatment: This is a readily available (from your doctor or veterinarian) disinfectant, antiseptic and spermicide that has been successfully used to treat early stage Chytrid (also sold by perscription as Sporonox or itraconazole). This chemical is more toxic if used in soft water with a low pH and it has been reported by some that have tried this treatment that it does not work. Use 2mg (0.2ml of a 1% solution) per liter of water at the appropriate temp as a 30 minute bath every 3 days for 6 treatments. Another regiment suggests a treatment every 2 days for 3 times, skip a week and repeat 3 more times for a total of 6. Use a clean water rinse bath after each treatment. Follow all quarantine, sanitation and disposal protocols.

Chloramphenicol Treatment: This is a very cheap antibiotic that has been shown to be effective for treating frogs with Chytrid. It should be dissolved in a small amount of hot water before making the solution. Frogs are kept partially immersed in a 10 to 20 ppm solution for 2 to 4 weeks. Change the solution daily and clean out the enclosure as needed. No ill effects have been reported even after a test treatment lasting for 3 months.

Indications of some resistance to re-infection have been noted. Chloramphenicol has been banned in the US as a treatment for aquarium fish because it may cause aplastic anaemia or other health problems in humans. Care must be exercised if it is to be used and consulting with your doctor beforehand is recommended.

Formalin/Malachite Green Treatment: This is a potent mixture sold to treat fish for parasite, fungus and bacterial infections. To treat Chytrid, use 0.007 ml per liter of water (½ drop per gallon?), added every other day for four treatments. Bright light will reduce the effectiveness of malachite green and it should be stored in the dark. Both chemicals can be harmful to humans.

Prognosis: Not good at this time. It is not likely that a miracle cure is going to come anytime soon. Much more work needs to be done to help save many amphibian species from going extinct. It is also important for the pet trade to take steps to reduce the spread of Chytrid. We have not seen much, if anything, that is being done to inform the pet buying public.

It is not the intention of this article to encourage anyone to practice veterinary medicine without the proper training. It is always a good idea to consult with a veterinarian. However, Chytrid is a very serious problem that needs to be dealt with on many levels. Tropical fish medications have been widely available for many years and have saved the lives of countless fish. Something similar to treat amphibian Chytrid would be very beneficial indeed. Information about treatments needs to be widely shared and updated as needed.

This article is a compilation of info from many different sources and may contain errors or inaccurate data. It is far from complete and more input is needed. Please feel free to use it in any helpful way and distribute it freely. Any updates or corrections sent to us will be greatly appreciated. Thanks! Dave & Donna Rucker, Pet LifeForms