Domesticated animals, wildlife, humans. All of these groups can be affected by cancer. In deer, such diseases are caused by viruses of the genus Papillomavirus. Increasingly frequent occurrences are bringing fibropapilomatosis of deer to the attention of not only hunters. Scientists from Slovakia and the Faculty of Forestry and Wood Sciences at the CULS focused on the occurrence and characteristics of this disease in roe deer.
The first cases studied appeared in the second half of the 20th century, for example, in white-tailed deer, reindeer or red deer. Data on deer fibropapilomatosis in Slovakia are known for a relatively short time.
Beware of open wounds! The disease is transmitted in the wild by contact of the mucous membranes or injured skin with infected material when it encounters a sick individual, or by rubbing against a contaminated environment (vegetation). Thus, roe deer can become infected, for example, by rubbing antlers or marking territory. Transmission through blood-sucking insects such as ticks or louse fly is also possible.
The research began together with the first case of fibropapilomatosis in a 3-year-old roe deer in 1998. Based on the examination of 610 roe deer and confirmed cases of the disease, the spatial spread and manifestation of the disease were assessed. Infected individuals were divided by sex and males also by age. Furthermore, categories were created depending on the number of tumours and their size.
Changes in the ratio of infected females to males were noted during the study. While initially the share of sick males was 94.1% and females 5.9%, in 2014 does already made up more than a quarter of sick individuals. Regarding the age distribution of infested males, young individuals (2-5 years) significantly predominated. The spread of fibropapilomatosis was as follows; since the first case, which was reported in the district of Senica, the disease has spread southeast. Between 2003 and 2004, there was a more than twofold increase in the number of infected individuals. Nine years after the start of the study, the presence of the disease was reported in 13 districts and by 2014 even in almost half of the districts of the Slovak Republic.
The results showed that most deer had from 1 to 10 tumours on the body and about a third were affected by 11 to 30 tumours. In terms of size, medium-sized tumours predominated in males and small tumours in females. The most frequently infected area of ??the body was the abdomen in females and the abdomen and forelegs in males. In both sexes, the hips were the least affected. The results also showed that the size and number of tumours depended on the location on the body of the sick individual. The largest tumours were located on the abdomen, the smallest on the hips. Most tumours occurred on the hind legs and least on the hips.
Fibropapilomatosis should, with a few exceptions, not affect the condition of the game, and roe deer should not degrade the quality of the antlers. Exceptions are, for example, fibropapillomas, which grow around the oral cavity and eyes, thereby limiting or preventing food intake and sensory perception of the individual. Due to the fact that the surface of tumours is often abraded, secondary infections can enter the tissues in this way and thus contribute to the deterioration of the condition of the game.
"Methods of treating roe deer fibropapilomatosis have not been studied. It is known that practical procedures, such as vaccination, which are used in domestic cattle, are difficult, if not impossible, under natural conditions. Exceptionally, individual tumours can be surgically removed in individuals after immobilization,” adds Associate Professor Vladimír Hanzal. Prevention in the form of hunting infected individuals thus remains the main way of combating this disease. The basic aspect is also the good condition of the game, which depends, among other things, on the correct sexual and age structure of the population and the amount of game corresponding to the conditions of the habitat. If we want to control, reduce or best eradicate deer fibropapilomatosis, it is necessary to follow hunting plans, take care of proper feeding and strive for natural population density, thus generally increasing the resilience of game and the ecosystem as a whole.
Rajský, D., Rajský, M., Garaj, P., Kropil, R., Ivan, M., Vodnansky, M., Hanzal, V. and Erdélyi, K. (2016). Emergence and expansion of roe deer (Capreolus capreolus) fibropapillomatosis in Slovakia. European Journal of Wildlife Research. 62, 43 - 49.
doc. Ing. Vladimir Hanzal, CSc.
He is a teacher at the Faculty of Forestry and Wood Sciences of the Czech University of Life Sciences in Prague, while he does not neglect publishing activities. Among other things, he is a forensic expert in the field of game management.
Prepared by: Lucie Hambálková