Interactions between four species in a complex wildlife: livestock disease community: implications for Mycobacterium bovis maintenance and transmission

Abstract

Livestock diseases such as bovine tuberculosis can have considerable negative effects on human health and economic activity. Wildlife reservoirs often hinder disease eradication in sympatric livestock populations. Therefore, quantifying interactions between wildlife and livestock is an important aspect of understanding disease persistence. This study was conducted on an extensive cattle farm in southwest Spain, where cattle, domestic pigs, wild boar and red deer are considered to be part of a tuberculosis host community. We tested the hypothesis that the frequency of both types of interactions would be greater at food and water sites, due to the aggregation of individuals from multiple species at these locations. We measured direct and indirect interactions between individuals using GPS and proximity loggers. Over 57,000 direct interactions were recorded over a 2-year period, of which 875 (1.5 %) occurred between different species and 216 (0.38 %) occurred between wildlife and livestock. Most direct and indirect interactions occurred at water sites. Over 90 % of indirect interactions between wildlife and livestock took place within the estimated 3-day environmental survival time of Mycobacterium bovis in this habitat. Red deer home ranges and daily activity patterns revealed significant spatial and temporal overlaps with cattle, particularly in autumn. Suids and red deer also cross the farm boundary regularly, introducing a between-farm interaction risk. The infrequent occurrence of direct interactions between individuals from different species suggests that they are unlikely to be the sole mode of disease transmission and that indirect interactions may play an important role.

Wildlife Interactions on Baited Places and Waterholes in a French Area Infected by Bovine Tuberculosis

“…This finding is consistent with previous studies showing the attractiveness of water points for wild boars, especially under dry and hot conditions (15, 18, 20, 34, 35, 37, 38). As a result, interactions among wild boars occurred more often at waterholes than at baited places.…”

“…Hence, supplementary feeding does not seem to be attractive for red deer in this area. In Spain also, red deer were rarely observed on feeding points compared to water points or pastures (20, 34, 35). In contrast, wild deer from North America such as elks ( C. elaphus ) and white-tailed deer use cattle-feeding areas (42–44).…”

“…Previous studies showed that artificial feeding and water points may aggregate wild populations, leading to direct and indirect interactions favoring bTB transmission (16–20). Furthermore, M. bovis transmission through shared feed has been demonstrated both among white-tailed deer ( Odocoileus virginianus ) and between white-tailed deer and cattle (21, 22).…”

Evaluating wildlife-cattle contact rates to improve the understanding of dynamics of bovine tuberculosis transmission in Michigan, USA

“…where stationary loggers were installed. Bovine TB is known to survive in the environment and remain infectious depending on weather conditions (Fine et al, 2011;Cowie et al, 2015). We assumed a fixed 30-day infectious period for cooler periods (1 Oct-1 May) and 7 days for warmer periods (2 May-30 Sept; Fine et al, 2011) as an approximation to the average environmental persistence of bTB (i.e., appropriate intervals of indirect contact).…”

“…Multi-host-species pathogens that are capable of being transmitted directly and indirectly, such as M. bovis, pose unique challenges to understanding risk and targeting mitigation to curb transmission (Cowie et al, 2015). Further, cryptic behavior of wildlife makes quantification of direct inter-species contact rates non-trivial and the ability to determine where, when, and how indirect interactions lead to transmission requires high-resolution contact data (Blyton et al, 2014).…”