The expansion of the livestock industry presents a potential for the transmission and spread of livestock diseases among wildlife populations, which can then become foci for human infection. Brucella suis, for example, has been shown to be transmissible to white-tailed deer (183), while B. melitensis can be transmitted to fish, with the possibility of transmission to humans (193). BSE has been transferred from livestock to domestic cats in Europe (165).

Wildlife are also important transport vehicles for livestock pathogens. Tapeworm eggs have been demonstrated to travel 60 km on wildlife against the prevailing wind (217). Cysts of Cryptosporidium and Giardia may be ingested with contaminated water by waterfowl and transported considerable distances (68). Therefore a disease outbreak cannot be contained if wildlife comes into contact with manure or polluted surface water. Human drinking water sources at some distance may become tainted. What are the implications, for example, of waterfowl who land on a lagoon, or a field spread with manure, and subsequently land on a reservoir such as Deacon Reservoir, or Mary Jane Reservoir? Protozoan cysts and helminthic eggs will not be killed by chlorination.

A special case which must be addressed is the problem of escaped livestock which become wildlife. Wild boars, for example, have been a concern for residents of the Beausejour area for several years. When some boars escaped from an insecure enclosure, they multiplied rapidly in the wild and overwintered easily in the bush. At one point a couple of hundred were roaming about the area, terrorizing residents, preventing cattle from having access to pasture dugouts, and digging up terrain, causing substantial damage. These animals have the potential to transmit pathogens as well as to pose a significant danger to the safety of people. The issue was argued extensively regarding whose jurisdiction was applicable: were they still livestock, and the responsibility of the Agriculture Department, or were they wildlife and the responsibility of the Conservation Department? The Agriculture Department did not feel accountable that it had started this problem. It became the municipality's responsibility to hire an animal control service to try to eradicate the animals, which proved a very difficult undertaking indeed.

Recommendations

$ Every precaution should be taken to minimize contact of wildlife with manure.

$ Drinking water sources must be safeguarded from coming into contact with wildlife, or, if this is not possible, as in a reservoir, appropriate treatment must be mandatory. Simple chlorination will not kill eggs, cysts, or some types of bacteria.

$ The issue of escaped livestock which adapt to the wild must be addressed as these may cause significant damage to property and pose health risks for people, livestock and wildlife.