Infectious Disease Outbreak Associated With Supplementary Feeding of Semi-domesticated Reindeer

Abstract

Supplementary winter feeding of semi-domesticated reindeer ( Rangifer tarandus tarandus ) has become more common in Sweden and Norway due to reindeer pasture fragmentation and climatic conditions. With increased corralling and feeding, often associated with animal stress, increased animal-to-animal contact, and poor hygienic conditions, an altered range of health challenges and diseases may emerge. An outbreak of three different infectious diseases appeared simultaneously in a reindeer herd in Norrbotten County, Sweden. The animals were corralled and fed silage. Several animals in poor body condition stopped eating, with drool and discoloration of the hair coat around the mouth. There were large, black, necrotic lesions on the tongue and gingiva, with holes perforating the chin, indicative of oral necrobacillosis and Fusobacterium spp. infection. Simultaneously, animals were seen with proliferative lesions in the oral mucosa and on the lips, characteristic of contagious ecthyma and Orf virus infection. Furthermore, three animals had keratoconjunctivitis suggesting exposure to cervid herpesvirus 2 (CvHV2) and possibly secondary bacterial infections. DNA specific for Fusobacterium necrophorum and ORFV was detected in relevant tissue samples. Antibodies against CvHV2 were detected in 10 of 13 diseased and in four of 11 apparently healthy reindeer. Nine animals were found dead or were euthanized during the outbreak. Health risk factors associated with feeding and corralling may severely impact animal welfare and the herder's economy, and may represent an underestimated cost when replacing natural grazing with feeding.

Spreading or Gathering? Can Traditional Knowledge Be a Resource to Tackle Reindeer Diseases Associated with Climate Change?

“…This statement is very interesting and relevant to the feeding boom we experience today, and is also in line with veterinary sources from the shift between the 19th and 20th centuries [ 42 , 43 , 44 ], which substantiate that professional authorities clearly saw the connection between infectious disease(s) and herding practice. Bergman [ 42 ] stated as a general picture for Sweden: ”In Sweden it is generally acknowledged that the infection spread more easily with the intensive reindeer herding, when the reindeer during summer are kept under continuous guarding on a restricted room in reindeer corrals for milking” .…”

“…In addition, feeding, especially over longer periods of time and in corrals, increases animal density and challenges reindeer with unfavorable hygienic conditions, quite similar to the experience and traditional knowledge referred to above with regard to slubbo and its association with milking practice [ 34 , 79 ]. Several outbreaks of IKC, contagious ecthyma, and alimentary necrobacillosis have been documented during the past few years in reindeer herds on different feeding regimes in corrals, sometimes affecting several dozens of animals [ 44 , 80 ].…”

“…Historically, the gathering of reindeer for milking was a practice that promoted digital necrobacillosis [ 43 ]. While the digital form of necrobacillosis practically vanished from the semi-domesticated reindeer in Fennoscandia after the termination of milking, as well as after the switch to larger herds and to extensive herding, the oral form of the disease has been increasingly appearing, associated with new practices of supplementary feeding [ 34 , 44 ].…”

Screening of Eurasian Tundra Reindeer for Viral Sequences by Next-Generation Sequencing

“…Thus, opportunistic infections might become a more frequent threat. Infectious diseases of the mucosa of the eyes and mouth are increasingly being observed [ 8 , 9 ]. Arctic wildlife and indigenous peoples’ health are especially at risk due to their dependence on subsistence food resources and the fact that climate change will have a greater impact in the area [ 10 ].…”

A Mini-Review of Ixodes Ticks Climate Sensitive Infection Dispersion Risk in the Nordic Region

“…Recent research on the presence and distribution of reindeer pathogens in northern Norway [ 2 , 3 ], historical literature on reindeer husbandry and diseases in northern Scandinavia [ 4 , 5 , 6 ] and information from reindeer herders and resource managers on animal diseases highlighted six potentially significant CSIs: Anaplasmosis, babesiosis, parapox virus, tularemia, necrobacillosis and anthrax. In this paper we focus on a subset of these CSIs, transmitted by the Ixodes ricinus tick [ 7 ], namely anaplasmosis, babesiosis and tularemia.…”