Researchers from the Department of Invertebrate Zoology and Parasitology discovered and described a hitherto unknown species of parasite, a new representative of the bison nose mite family. Until recently, only three out of 90 species of bison-specific parasites were known. Thanks to the scientists from the University of Gdańsk, we managed to discover the fourth one. The paper dedicated to this discovery was published in a prestigious parasitological journal International Journal for Parasitology: Parasites and Wildlife.

Dr hab. Joanna Izdebska, prof. UG from the Department of Invertebrate Zoology and Parasitology of the Faculty of Biology, UG, talks about the new species of the bison parasite.

Elżbieta Michalak-Witkowska: - I guess that your discovery was not accidental, please tell us how it came about?

Dr hab. Joanna Izdebska, prof. UG: - It is true, it is the consequence of many years of experience. While researching parasitic arthropods of European bison and many other mammals, still at the stage of my PhD thesis, I started to specialize in a methodologically difficult and poorly known group - skin and tissue mites, especially in the family of Demodecidae. For several years prof. Leszek Rolbiecki, a colleague from the same Department, who also specialises in parasitology, has been cooperating with me in this research.

- Demodex are quite dangerous, pathogenic parasites.

- Demodecidae are specific parasites of mammals that can cause a dangerous, even fatal disease - demodicosis. Different mammals have their own species of these parasites, sometimes several in different locations. More species, due to their pathogenic importance, are known from humans and domestic and farm mammals. Less information is available on demoted from wild mammals, where these mites are often asymptomatic. They are among the smallest animals and their microscopic size and hidden lifestyle (in the skin, including hair follicles, various glands, epidermis, but also in ear canals, tongue, gums, etc.) make them very difficult to detect. However, the method I have developed makes it possible to detect their asymptomatic presence in the skin and other tissues.

- You mentioned that you have discovered and described more than 20 species of these mites, which represents nearly 20% of all known representatives of this group in the world.

- Yes, including specific parasites of various rodents - house mice, common rats, field, forest and scrub mice, Indian bandicoots, common voles, European beavers; shrews - the lesser white-toothed shrew; bats - the brown long-eared bat; and carnivores - the otter, the domestic dog, and ungulates - the European bison. We have also carried out detailed studies of other species, previously known sometimes from single publications, sometimes even a hundred years ago (e.g. borers from the mole, common shrew, bank vole, badger, common seal, European red deer), but also common and pathogenic (e.g. from man).

- How much do parasites threaten bison and how can data on a new parasite species help?

- Our study allows us not only to learn about the biodiversity of these parasitic mites, common in mammalian populations but also to analyse adaptations to parasitism and the functioning of the parasite-host system, i.e. to learn about different interactions between mites and mammals. This will contribute to the elucidation of the mechanisms of aetiology and pathogenesis of the diseases they cause (different variants of demodicosis), which are difficult both in terms of diagnosis and treatment. It also allows the development of diagnostic methods related to the detection, but also the correct species identification of these parasites (different species may cause different symptoms), which is a problem in veterinary research. So far, for example, we have verified the systematic status of all known species of canine Demodex causing difficult to treat, chronic and even fatal canine demodicosis (demodicosis canina).

Of particular interest is the bison, which became extinct in the wild and the current population has been rebuilt with only a few individuals from breeding conditions. This resulted in the loss of the natural parasite fauna, whose place was taken by parasites from other ungulates - deer or cattle. Only a few specific parasites survived with the last bison - the blood parasite Trypanosoma wrublewskii, the hair louse Bisonicola sedecimdecembrii, and two species of skin parasites - Demodex, including the newly discovered one.

In the case of European bison, the study of parasite fauna is of particular importance, as this is an endangered animal, which as a result of the restitution of the species has a small gene pool, resulting in reduced immunity and increased susceptibility to various diseases. Our studies on parasitic arthropods (e.g. ticks, scabies), point to their role in disease transmission or tissue damage as gateways for infection with various pathogens. Specific nematodes (discovered by us - currently Demodex bialoviensis and earlier - Demodex bisonianus) do not cause dangerous disease symptoms in bison, which is typical for evolutionarily old parasite-host systems, where parasites in the course of evolution have adapted perfectly to living in the host and are less burdensome for it. However, in the case of European bison, one should also take into account the possibility of indirect consequences of parasitism, i.e. mechanical transmission of pathogens or, by penetrating tissues, creating the possibility of infections.

- Under which project was the research conducted?

- Actually, it was not a specific project, but a result of long-term research on bison parasite fauna. Bison is one of my favourite animals and at the same time a flagship of Polish and world nature conservation. We have been studying them for many years - together with prof. Leszek Rolbiecki we conduct parasitological analyses, and our co-author from the Faculty of Veterinary Medicine at Warsaw Agricultural University, prof. Wojciech Bielecki specialises in pathology. We are active members of the international scientific society - European Bison Friends Society, which deals with research and conservation of European bison in the world.

My research has been going on for more than thirty years - it was the topic of my doctoral thesis, and after it was finalized, the work was continued in different directions, including the role of parasitic arthropods in the transmission of bison dangerous diseases. A summary of this research can be found here: https://www.mdpi.com/1424-2818/14/2/75/htm

- Thank you for the interview.