Amanda Bennett and Matt Keevil have been doing research on two amphibian diseases for the past year. The virus “Ranavirus” causes a hemorrhagic disease in amphibians (think frog Ebola). Frogs will have red patches and bloating under their skin, and may have trouble hopping or swimming. The fungus “Batrachochytrium dendrobatidis” (Bd) causes the disease “chytridiomycosis” (chytrid). Did you know frogs use both their lungs and their skin to breathe? Chytrid causes skin damage, making it difficult for frogs to breathe. Frogs with chytrid may have peeling or redness on their skin and may be unable to hop or swim well. In tadpoles, the fungus attacks their mouthparts, which can make eating difficult. They will appear skinny and tired. Another chytrid fungus (“Bsal”) has been causing problems for salamanders in Europe, though it has not (yet) made it to North America.
These diseases have caused devastating losses in frog and salamander populations around the world. In Ontario, they have caused sporadic die-offs in frog populations; however, these die-offs can go undetected. The onset of the illness to the end of a die-off may only be one to five days, but there will usually be a large number of dead or dying frogs near the pond. These frogs do not last long, though, as they get eaten by scavengers or decompose in a few days. If you ever come across a number of dead or dying frogs, the best thing to do is to take some photographs and contact the Canadian Wildlife Health Cooperative, a cross-Canada network dedicated to studying and protecting wildlife health.
To help prevent the spread of disease, it is important to disinfect your hands after handling a frog — an alcohol-based hand sanitizer works great. Just make sure that all of the hand sanitizer is absorbed and to rinse with clean water before touching another frog — their skin is very sensitive, so rinsing with water is a good idea after applying sunscreen or bug spray! If you are walking in a wetland, getting water and mud on your boots, it is good practice to clean your boots, nets, or whatever other equipment you were using in the water.
Scrub the mud or dirt off with soap and water, give your equipment a good misting or rinse with a dilute bleach solution (30 mL of household bleach in 1 L of water works great). Let the solution sit for 5 minutes and rinse everything off with clean water. It’s important not to move frogs from one place to another and to never release pets or bait into the wild.
Luckily, we have not seen any cases of disease so far at rare. However, diseases that might not be causing a problem now can become problematic later. We know some frogs and salamanders can carry the virus and fungus without developing the disease, until other stresses weaken their immune systems. Pollution, habitat loss, warming temperatures, and dry summers can all make populations more susceptible to disease outbreaks.
Help frog populations by keeping your hands and boots clean, and your eyes and ears open!
You can report sightings of frogs and salamanders in Ontario to the Ontario Reptile and Amphibian Atlas via online form, email, mail, or download the app to your mobile device.
By Amanda Bennett
Amanda Bennett and Matt Keevil are researchers working on the Amphibian Disease Monitoring Project at Trent University. Their work focuses on mapping risk of emerging infectious diseases in amphibians to aid conservation efforts in Ontario. If you ever see something at rare that leaves you wondering, don’t hesitate to get in touch with us. We welcome your calls and emails to 519-650-9336 or email@example.com.