Diagnosis of enteric diseases in pigs(1).

Sampling by walking: The socks will be 
analysed after having visited the batch. In Denmark, reducing antibiotic treatments in Danish pig production has been a political aim for the past 20 years. A total ban on growth promoters was issued in 1999 which led to a situation where veterinarians only prescribe antibiotics for treatment of clinical cases of disease. As a consequence of an increased total consumption, the yellow card system was issued in 2008 - where farmers who exceed a certain level of antibiotics are penalized by the public authorities. It has resulted in more focus on reducing the antibiotic consumption, through prevention but also by reducing the number of treatment days and the dosage. This increased focus on reduction of antibiotic consumption has led to diseases like diarrhoea and intestinal infections being quite widespread in Denmark, especially in weaners but also finisher pigs where treatments for diarrhoea and intestinal infections are the number one indication for treatment. This has enhanced a lot of researches and techniques for the purpose of improving diagnostics for intestinal infections and, in the end, improving the possibilities of treatment and reducing the antibiotic consumption for these diseases. It became apparent from these studies that so-called Lawsonia diarrhoea was also caused by other bacteria, including E. coli, Brachyspira species and of course Lawsonia intracellularis. In the same period, quantitative PCR tests were developed, and these were validated in research projects in order to improve the diagnostic possibilities for each practicing veterinarian. This has led to the development of what is generally known as ‘the sock method’ which consists of taking a standard sock, walking around all pens in the section to be tested, and the sock is then tested with the quantitative PCR test. The number of bacteria can be used to assess the financial impact and whether there are health-related conditions present in the animals tested. One of the major challenges as a consequence of the reduction of antibiotics is that seven days’ treatment at certain times has been reduced to mainly clinical indication of maximum five days and in many cases down to three days’ treatment. At the same time, the dosage of antibiotics has also sometimes been reduced. Based on these changes in treatment strategies, the timing of antibiotic treatments at batch level has become extremely important. There is a very big risk of targeting pigs for antibiotic treatment at the wrong time and being either too soon or too late. This phenomenon is known from practice, but also from research it has turned out that batches of pigs without signs of diarrhoea can still reveal a very large proportion of animals having intestinal infections. On the other hand, there are situations where there are actually outbreaks of clinical diarrhoea with no or a low occurrence of bacterial intestinal infections in the pigs that have diarrhoea. These situations include conditions as ‘unspecific colitis’ or the newly defined ‘low pathogen’ (LP) diarrhoea. In a present PhD study, it is considered whether sock samples and laboratory diagnostics could be used routinely as a decision tool for determining when treatment should be started in the individual batch. The first preliminary results indicate that it is possible to a certain extent, but currently this would require repeated laboratory tests in each batch of pigs, taking up a considerable amount of time and effort. There is therefore a professional reason to develop such so-called ‘pen site tests’ where farmers will be able to assess the level of pathogens on a daily basis – even in batches without any clinical signs of disease. materials from pig progress.