[Methods for population-based herd sanitation: an overview].

Abstract

There is a considerable number of methods available for the development, maintenance and surveillance of specific-pathogen-free herds. The selection of a method for a specific remediation project is primarily dependent on the goal, the epidemiology of the agent to be eradicated, the feasibility and the available resources. At the beginning of the remediation programme, methods are required for the classification of the herd status. Clinical and analytical diagnostic tests may be used for individual herds or in an entire area. The interpretation of test results applied within a population deserves special attention. A series of techniques are available - alone or in combination - to remediate a herd that was classified as being infected: systematic treatment, vaccination, elimination of infected individual animals ("test and remove"), partial depopulation or total population (stamping out). These strategies are typically accompanied by cleaning and disinfection. After the remediation, the status of the herd needs to be certified and maintained. For the documentation of the status, monitoring and surveillance strategies such as clinical follow-up visits, notification systems and random sampling can be applied. When planning random surveys, statistical and epidemiological considerations are relevant. For the sustainable maintenance of the pathogen-free status, biosecurity measures at the individual farm level, but also broader approaches such as import restrictions, early warning systems and surveillance programmes are needed. General awareness regarding unusual clinical signs needs to be promoted among farmers and veterinarians. The longer a disease or an agent is absent from a herd or region, the lower becomes the risk awareness. In such a situation, mistakes can occur leading to an increased risk of re-infection.