Infectious diseases causing lameness in cattle with a main emphasis on digital dermatitis (Mortellaro disease)

Lameness in both dairy and beef cattle is a major welfare and economic problem. It results in milk yield reduction, reduced feed intake, weight loss, reduced fertility, and premature culling of affected animals. There is a wide range of infectious agents that are associated with lameness problems in cattle. Both systemic as well as localized infections may cause animals to have problems to move in a natural way. In particular, digital dermatitis (DD) is currently considered a leading cause of severe epidemic lameness in dairy herds, giving rise to major economic losses. This disease was first described in the seventies in Italy after which it has been recorded in different parts of the world with a large variation in prevalence. Surprisingly, despite the huge number of papers that are published regarding this disease, its pathogenesis is still not fully elucidated. Many studies have shown that Treponema spp. play a decisive role in the establishment of the disease, although it is not yet fully clear how exactly an infection with these germs leads to the very typical skin lesions. Some papers emphasized that similar complex microbial communities can be isolated from DD lesions in cows and periodontitis lesions in humans, giving rise to speculations about similarities in the typical inflammatory reaction provoked by an infection by these bacteria. Moreover, DD is considered a multifactorial disease, with besides infectious, also environmental, managerial and individual-animal factors likely playing a decisive role in its pathogenesis. These different contributing factors will be critically discussed in the present paper mainly aiming to come a step closer towards the full elucidation of the pathogenesis of this stubborn infectious disease. (C) 2013 Elsevier B.V. All rights reserved.