Action: Treat disease in wild mammals
Key messagesRead our guidance on Key messages before continuing
- Three studies evaluated the effects on mammals of treating disease in the wild. Two studies were in the USA and one was in Germany.
COMMUNITY RESPONSE (0 STUDIES)
POPULATION RESPONSE (2 STUDIES)
- Condition (2 studies): A replicated study in Germany found that medical treatment of mouflons against foot rot disease healed most infected animals. A before-and-after study in the USA found that management which included vaccination of Yellowstone bison did not reduce prevalence of brucellosis.
BEHAVIOUR (1 STUDY)
- Uptake (1 study): A study in the USA found that a molasses-based bait was readily consumed by white-tailed deer, including when it contained a dose of a disease vaccination.
Treatment of diseases in wild mammals can be problematic. It can be difficult to diagnose causes of illness and the administration of medicines directly to target individuals can be challenging. Except in cases of highly threatened species, treatment of disease in wild mammals is usually only carried out when there are potential economic costs of not treating, such as a risk of transmission to domestic animals or reductions in numbers or health of animals that have sporting value. This intervention includes cases where animals are confined for treatment (and one study on captive animals that trials a delivery mechanism for treatments that might be administered to wild mammals) but in all cases, the aim is to improve the health of wild populations.
See also: Use vaccination programme.
Supporting evidence from individual studies
A replicated study in 1994–2005 in three forest sites in Hessen and Rheinland-Pfalz, Germany (Volmer et al. 2008) found that medical treatment of mouflons Ovis gmelini musimon against foot rot disease healed most infected animals. No statistical analyses were performed. All 152 infected individuals fully treated for foot rot disease recovered with no signs of reinfection. No data are provided for 13 individuals that only received partial treatment. Two hundred and fifty mouflons were caught using a fenced kraal or net trap and kept in a corral for six weeks. All were injected with penicilline–streptomycine (1-3 ml of Tardomyocel III comp®), had an anti-parasitic treatment (0.2 mg/kg of Ivomec®) and, in cases of bad general condition (e.g. fever) a supplementary treatment was administered (see paper for details). A total of 165 animals with foot rot were treated by trimming the wounded hooves and covering them in antiseptic fluid (Kodan®-Tincture). Some were treated with an additional antibiotic injection (5.0 ml Procain Penicillin G® solution). If needed, a second treatment was conducted after two or three days. Four to six weeks after treatment, a final trimming of the hooves was undertaken before the animals were released.
A before-and-after study in 2001–2010 on grasslands in and around a national park in Wyoming, USA (White et al. 2011) found that intensive management, including vaccination, of Yellowstone bison Bison bison bison did not reduce prevalence of brucellosis Brucella abortus. The proportion of adult female bison testing positive for brucellosis increased or remained constant during the period at approximately 60%. However, transmission of brucellosis from bison to domestic cattle was almost eliminated. Bison were intensively managed, which included separating them from cattle on winter pastures, herding them into the park in spring, and periodic culls where these aims could not be achieved. A proportion of bison was tested for brucellosis and animals that tested positive were slaughtered. Bison, especially adult females, were vaccinated either when captured or by remote vaccine delivery. During 2001–2010, 1,643 bison that tested positive for brucellosis were slaughtered and 18 were released. A total of 1,517 bison that tested negative or were untested were also slaughtered. The overall population ranged from 2,432 to 5,015 during this period.
A study in 2012 on captive animals in Iowa, USA (Palmer et al. 2014) found that white-tailed deer Odocoileus virginianus readily consumed a molasses-based bait, including when it contained a dose of a disease vaccination. In 48 of 50 trials, all baits were consumed within three hours. However, on >62% of occasions, all baits in one serving were consumed by a single deer. All baits containing Mycobacterium bovis bacillus Calmette–Guerin (BCG) vaccine were consumed. Baits, containing flour, cane molasses, sugar, water, shortening, sodium bicarbonate and sodium chloride, were baked into 8-g pellets. Seven pellets were fed to deer in addition to their usual feed, in each of five pens (three each containing three deer, one with four deer and one with 50 deer) daily for 10 days. Consumption was observed using camera traps. Additionally, five baits containing 0.2 ml BCG were offered to three deer during January 2012, in addition to their usual feed.
- Volmer K., Hecht W., Weiß R. & Grauheding D. (2008) Treatment of foot rot in free-ranging mouflon (Ovis gmelini musimon) populations; does it make sense? European Journal of Wildlife Research, 54, 657-665
- White P.J., Wallen R.L., Geremia C., Treanor J.J. & Blanton D.W. (2011) Management of Yellowstone bison and brucellosis transmission risk – Implications for conservation and restoration. Biological Conservation, 144, 1322-1334
- Palmer M.V., Stafne M.R., Waters W.R., Thacker T.C. & Phillips G.E. (2014) Testing a molasses-based bait for oral vaccination of white-tailed deer (Odocoileus virginianus) against Mycobacterium bovis. European Journal of Wildlife Research, 60, 265-270