Mange is one of the biggest threats to Bare-nosed wombats and can wipe out isolated colonies in just a few years. It is geographically widespread and affects thousands of animals. Mange in wombats is caused by an infestation of the mite, Sarcoptes Scabiei, the same type of mite which causes scabies in humans and mange in dogs, (there are many "sub-species" of the mite). The female mite buries into the tissue while depositing eggs as well as leaving her waste behind, causing intense itchiness which leads to thick scabby plaques, and flyblown fissures. Eventually the wombat will die a slow painful death. Leaving wombats with sarcoptic mange to die is unethical and likely to lead to more wombats dying from mange. We have been carrying out extensive mange treatment programs covering large areas of private property and state forest over the past 15 years and have now a good success rate with a treatment duration of only 30 days, with flexibility for different individual response. See article of our successful mange treatment in the District Bulletin. For additional information on mange see Wombat Protection Society of Australia.
We treat all adult free-living wombats in situ with our preferred method using a long pole with a scoop attached to the end. Cydectin (Moxidectin) is placed in the scoop and we carefully approach the affected wombat and pour the chemical directly along the back of the wombat. Allowing the wombat to then go where it prefers, we quietly follow and he/she will often lead us to the burrow it currently uses. This method allows us to monitor how much of the chemical the wombat actually receives on his back. Depending on how accessible the wombat is, treatment plans are made for each individual and the possibility of others also with mange in the same area. As the wombat improves, it sometimes become harder to approach, they are quicker and generally less cooperative, they change their habits and move burrows.
If the wombat with mange is in a new area where we have not treated recently, we assume there are others with different degree of mange. We set up flaps with smaller doses at burrow entrances in the vicinity of the affected area and target areas around creeks and water sources, (wombats with mange get dehydrated and will be where there is water). As flaps give a smaller dose and is difficult to target specific individuals, they are good as a prophylactic treatment for wombats of an area. We have seen a healthy wombat go down a burrow followed by a “manged” wombat, we set up a flap, waited and watched, the healthy wombat came out first receiving the dose while the wombat with mange missed the dose entirely. We also use remote night sensor cameras as an additional tool when flaps are in use.
The correct dose rate is the amount that will actually reach the circulatory system to kill the mites without overdosing the wombat. This is hard to establish because different wombats react to treatment in variable ways. Some shake off the Cydectin immediately while others have a delayed shake and some don’t shake it off at all. Some have fur filled with dirt or clay particles from their burrowing behaviour preventing absorption of the Cydectin through the skin. Some have highly developed plaques preventing absorption and some seem to have fur type that dissipates the pour on rather than absorbing it. Some have a combination of all these factors. The reasonably healthy clean skinned wombat has, in any case a much thicker dermis than animals these pour on were developed for. Research has shown that the half-life (the duration of action) varied from 2 to 9 days (Death et.al 2011) with an average of five days, indicating huge variability and different results to those of red cattle and deer. Finally, Cydectin pour-on was developed as a preventative to stop mites developing on cattle and deer, not to treat developed cases of mange infestation in wombats.
Our current treatment regime over the past few years is a treatment duration of 30 days only, with intense treatment during the first seven days. We believe it is important all mites are killed quickly to prevent the mites building up resistant to the chemical and prevent the wombat being sick for too long. It also reduces the risk of the wombat “disappearing” before all mites have been killed. It is not always obvious when all mites have been killed and we therefore continue to monitor for many months or as long as we can, especially until their body weight is back to normal. This is of course not always possible with free-living wombats and therefore we adjust to each individual, considering the weather, and time of the year. It takes a long time for the wombat to lose all the scabs and plaques, regrow the fur and put on weight but all worth the work to see them become a healthy wombat again.