Naslov
Olm Conservation and Medicine in Croatia

Autori
Lukač, Maja ; Cizelj, Ivan ; Horvatek Tomić, Danijela ; Prukner-Radovčić, Estella ; Holtze, Susanne ; Hildebrandt, Thomas ; Gottstein, Željko ; Jelić, Dušan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, prošireni sažetak, znanstveni

ISBN
978-615-5392-20-7

Skup
Diseases of Fish, Amphibians and Reptiles

Mjesto i datum
Budimpešta, Mađarska, 22.03.2019. - 24.03.2019

Vrsta sudjelovanja
Plenarno

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Olm, medicine, conservation

Sažetak
Proteus anguinus (the olm) is an amphibian endemic to the subterranean waters of caves in the Dinaric karst, inhabiting areas from northern Italy and southern Slovenia to southwestern Croatia and Bosnia and Herzegovina1. It is the only real cave-dwelling chordate found in Europe. Due to olm's troglomorphic and neotenous characteristics, this species is adapted to a life in complete darkness in its underground habitats. Proteus anguinus is the only species in the Proteus genus and the only European species of the Proteidae family. With the average lifespan of 68.5 years, olms are the longest living amphibian species2. The olm is extremely vulnerable to changes in its environment and is threatened by an increasing and uncontrolled spreading of urban areas and human-made infrastructure, and the excessive pollution of water habitats3. Also, heavy rains or waters from melted snow may wash the olms out from their habitat at certain localities in Croatia, bringing them to the surface of the ground. The animals are not able to survive for a longer period of time due to unnatural environmental conditions and secondary bacterial and fungal infections of skin injuries. Moreover, on the field they could come into contact with the vectors of infectious diseases. Owing to their elusive way of life in underground karst, the data on their real distribution, number of animals at different localities and potential health problems they could suffer from is very scarce. To get as much as possible information about the olms, in order to protect the animals and their habitats from various threats, the research project entitled „The olm (Proteus anguinus) in Croatia – conservation research project“ started in 2011, conducted by the Croatian Herpetological Society and Croatian Institute for Biodiversity, with the Hungarian Nature History Museum (Budapest), Zoological Society of London, Zagreb Zoo, and Faculty of Veterinary Medicine, University of Zagreb as key partners. The project had two parts, the field research and conservation, and ex situ research and conservation. The aim of the field research was the confirmation of known localities and counting the individuals to get better picture about population structure and size, along with the search for new localities. In accessible caves this was done by trained speleodivers and biologists, while the olm presence in non-accessible cave systems was assessed by environmental DNA analysis of water samples. The aim of this part was also the raising of public awareness about human impact on the olms habitats, and cleaning of cave entrances. The aim of the ex situ conservation and research was to get the information about the olm health status using various methods. The primary idea was to investigate the possibility of returning the flushed individuals back to their habitats by identifying microorganisms harbored by olms, to distinguish between normal, opportunistic and real pathogens. It was also intended to develop optimal treatment and preventive measures in case of confirmation of infectious diseases. Therefore, skin, cloacal, and oral cavity swabs of the flushed olms and those from their natural habitats were collected, along with the water from their localities. Flushed olms are the animals being flushed from their natural habitats during the periods of excessive rain or fast snow melting. These animals die on the field due to unnatural conditions of excessive light, high temperatures and desiccation. To prevent the spreading of potential diseases from the field to underground habitats it is not advisable to release the animals back to their habitats. On some localities this is also not possible due to construction of the springs. Therefore, the project got the permission for collection of all flushed animals for scientific purposes and for their accommodation in the specially designed cold room meeting all the needs regarding the temperature, water circulation and conductivity, light, and food preferences, situated backstage of the Zagreb Zoo. To compare the microorganisms from flushed animals with those from their natural habitats, control animals were also included in the research. Standard microbiological procedures for detection of bacteria and fungi, and the qPCR for detection of Chlamydia sp., Batrachochytrium dendrobatidis, Batrachochytrium salamandrivorans and Ranavirus were performed. Bacteriology of samples was also performed by the next generation sequencing (NGS) at the Veterinary Research Institute Brno, Czech Republic. For intestinal parasite detection, native smears and fecal floatation from alive animals and intestinal scrapings from dead ones were used. For detection of Chloromyxum protei, kidneys of dead animals were investigated. Pathohistology of all dead animals was performed to determine the cause of death. In cooperation with the colleagues from the Leibniz Institute for Zoo and Wildlife Research, ultrasound examination of animals for monitoring of general health and reproductive status of animals was performed. Standard microbiology procedures showed more bacterial isolates in flushed animals than in those from original localities. The most common isolates in flushed animals were Acinetobacter johnsonii, Aeromonas hydrophila, Bacillus sp., Butiauxiella agrestis and Janthinobacterium lividum. Bacillus sp. and Pseudomonas fluorescens were the most common isolates in animals from original sites. Fungi (Aspergillus spp., Penicillium sp., Fusarium roseum and Rhodotorula rubra) were isolated only from flushed animals, while all of the animals from original sites were free of fungi. The higher number of bacterial and fungal isolates in flushed animals could be due to their exposure to unnatural conditions on the field where they suffered from immunosuppression and were surrounded by soil microorganisms. All of bacteria isolated from the water, with the exception of Microbacterium maritypicum, were also present in animals, indicating close relation between animal microbiota and the environment. Next generation sequencing results revealed the presence of Methylotenera sp. and Metyloversatilis sp. in the skin and oral cavity of the animals. The role of these microbes in olm biology, along with other results obtained by NGS needs further analysis. Feces and intestinal scrapings were free of parasites, but the occlusion of kidney tubules by myxozoan plasmodia and degeneration of epithelial cell layers were present in three dead animals. All of the animals so far have been negative to Ranavirus, Chlamydia sp., Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans. Microbiology results acquired so far did not reveal the presence of real pathogens of infectious diseases in any animal, but various types of bacteria able to cause disease in immunocompromised animals were isolated from flushed individuals. Janthinobacterium lividum, a violacein producing organism, has already been described to poses antifungal properties, especially against chytrid fungi4, 5. The use of ultrasound has been proven as a useful and non–invasive diagnostic tool for gender determination, heart rate assessment and monitoring of internal organ function6. From the beginning of the project until today, many various institutions and researchers have been interested in different research areas of olm biology, so that a lot of information about this special amphibian has been collected in the past few years. Today, our knowledge is more extensive than at the start of the project and this will hopefully assist in the preservation of the olms, but the further research is still in progress.

Izvorni jezik
Engleski

Znanstvena područja
Veterinarska medicina

POVEZANOST RADA