What is it
It is the most serious disease affecting chamois and wild ibex, caused by a tiny mite, invisible to the naked eye: Sarcoptes scabini var. rupicaprae.
The females of the mite dig galleries in the skin of the animals, where they lay their eggs. While they dig these galleries, they also let out toxic substances.
The affected animals scratch insistently, rubbing themselves against trunks and rocks. They lose hair on the neck and the snout. As the disease advances, areas with no hair on the body and the belly appear. On the skin, fissured crusts appear. The animals eat a little and become weaker and weaker, until they die.
In populations of chamois and wild ibex that have never been affected by sarcoptic mange plagues, the disease can even cause a mortality rate of over 95%. After a few years, the plague regresses, and the survivors reconstruct the population. The disease becomes endemic and can reappear with cycles of 7-15 years, but in these cases the mortality rate is much lower (10-15%).
Transmission
The disease is transmitted through the direct contact with the animals, in particular during the mating season (November-December) and in summer, in the feeding and cub growing stages.
Sarcoptic mange can be transmitted from the chamois to the wild ibex and to the domestic goat, and the latter can infect further wild Ungulates. The cases on roe deer, deer, mouflon, fallow deer, and sheep are rare.
Man is not affected by the disease but, in case of manipulation of infected animals carried out without adequate protection measures, this may cause possible allergic reactions with an intense reddening of the skin and itching.
Sarcoptic Mange in Italy
The disease has been known since the early 20th century, when it was described in Germany and France. In Italy it appeared in 1949 in Alpi Carniche and in Tarvisiano area. In the rest of the central-eastern Alps, there have been two strong plagues: one in 1976 and one in 1995. The second is still ongoing and is interesting the provinces of Bolzano, Trento, and Belluno.
Sarcoptic Mange in Dolomiti Bellunesi National Park
In Dolomiti Bellunesi National Park, the first case of sarcoptic mange was registered in June 2009. On 31st December 2009, the cases registered in the Park area were two.
The chamois population of the Park is constantly monitored by the staff of the National Forest Service in order to examine the presence of new cases and the evolution of the disease within the protected area.
Since 2004, the Park has been carrying out in association with the University of Ferrara a genetic study on the chamois population, taking DNA samples. The aim is to search for eventual genetic differences between the chamois populations that have already been affected by the plague outside the Park and the populations that have not yet been strongly affected.
Because of the appearance of the disease, the Park has stopped the ongoing reintroduction project of the wild ibex in order to avoid that the newly released animals could be infected.
How to Fight against it
The disease spreads throughout the territory with a speed of about 7-9 km per year.
In the areas interested by the plague, the infected animals have been eliminated in order to contain the infection.
However, these measures have not led to the expected results. Studies carried out in various areas of the alpine chain have demonstrated that there are no relevant differences in the minimum density reached by the population at the climax of the plague between the areas where the infected animals were killed to “slow down the infection” and the areas where the animals were not killed.
As a matter of fact, it is not possible to know if the animal will be able to survive the disease. Therefore, with the killings, we risk to eliminate the few eventually resistant animals: the animals that are in charge of reconstructing the population after the plague.
For this reason, in the territory of Dolomiti Bellunesi National Park, we will not kill the infected animals, even if the diffusion of the disease should increase in the next years.
Only seriously infected animals may be killed, if found near mountain huts or trails.
This choice may lead in the future to high mortality rates, but it guarantees a faster reconstruction of the population.