Proliferative enteropathy (PE) caused by Lawsonia intracellularis and swine dysentery (SD) with the etiological agent Brachyspira hyodysenteriae are the most common bacterial diarrheal diseases affecting pigs during the growing and finishing stages of production. The economic impact of PE and SD on swine production is attributable to mortality, reduced feed efficacy, costs of medication and additional animal care. The objective of this study was to investigate the prevalence of L. intracellularis and B. hyodysenteriae infections in diarrheic and/or poor growth of pigs by examination of fecal samples obtained from Polish farms with farrow to finish production. On the basis of clinical interviews in 200 medium and large-scale farrow-to-finish pig holdings, 66 farms were chosen for further laboratory examinations. In the investigated farms diarrhoea and/or diversity in body weight was observed in weaners and finishers. Chosen farms were divided into 2 groups: farrow-to-finish medium-scale farms with up to 100 sows (M Farm) - 26 farms; and large-scale farms (above 100 sows; L Farm) - 40 farms. In each kind of farm laboratory examinations for detection of B. hyodysenteriae and L. intracellularis in 18 fecal samples from pigs with diarrhoea or, in absence of diarrhoea, from pigs with a weaker condition were taken. Every 3 fecal samples were put together in one collective sample. The fecal samples were analyzed by nested PCR (L. intracellularis) and PCR (B. hyodysenteriae). L. intracellularis was found in 133 of the 396 fecal samples, which gives a prevalence level of 33.58%. Of the 66 farms tested, 41 (62.12%) were positive for PE. Brachyspira hyodysenteriae was detected in 54 (13.63%) of the 396 tested fecal samples. Of 66 investigated farms suspected of SD 21 (31.81%) were positive. Analyzing the infection level of B. hyodysenteriae with reference to farm size it was observed that 26.92% of medium scale farms and 35.0% of large scale farms were infected. The difference between medium and large farms was distinct concerning PE. From 26 M farms 12 (46.15%) and in case of farms L 72.5% were infected. Our findings show that the prevalence of L. intracellularis in infected farrow-to-finish medium and large scale farms was distinctly higher than the level of B. hyodysenteriae infection. Mixed infections with the mentioned bacteria are also common. Studies on the prevalence of L. intracellularis and B. hyodysenteriae infections showed that these pathogens are widely distributed in the swine population of Poland.
Principal aim of this study was to examine fecal samples from pigs suffering from diarrhea for the presence of Lawsonia intracellularis, Brachyspira hyodysenteriae and Brachyspira pilosicoli. The molecular techniques such as PCR and nested PCR were employed to detect the presence of p78 fragment of genomic DNA specific for Lawsonia intracellularis as well as fragment of tlyA gene specific for Brachyspira hyodysenteriae and 16S rDNA gene of Brachyspira pilosicoli. We assumed that about 25% of pigs were infected with Lawsonia intracellularis, about 10% with Brachyspira hyodysenteriae and only 0,8% with Brachyspira pilosicoli. In about 3% mixed infection with L. intracellularis and B. hyodysenteriae was observed. Results were comparable in herds that differed in quantity, breeding technology, hygienic standards and preventive treatment with different chemotherapeutics.
Laboratory diagnosis of swine dysentery (SD) and proliferative enteropathy (PE) by standard bacteriological methods is time consuming and bears the risk of false negative results. Limitations concerning the isolation of L. intracellularis and difficulties with conventional bacteriological procedures were the primary reasons for developing a PCR for the diagnosis of PE and SD. The aim of this study was to develop a multiplex PCR for the detection of B. hyodysenteriae and L. intracellularis and to determine the usefulness of this technique in diagnosing the above mentioned diseases. The investigations were evaluated on strains of B. hyodysenteriae B204 and the bacterial filtrate of L. intracellularis. In order to determine the sensitivity of multiplex PCR from bacterial suspension (B. hyodysenteriae 2 × 108 cfu/ml) and (L. intracellularis - 1.1 × 106 cfu/ml) 10-fold dilutions were prepared in a Tris-HCl, pH 8.5 buffer or in supernatant of swine feces in Tris-HCl, pH 8.5 buffer. The elaborated multiplex PCR was able to detect 1.1 × 104 cfu/ml L. intracellularis and 2 × 105 cfu/ml B. hyodysenteriae. In analyzing the sensitivity of multiplex PCR in the presence of the two mentioned species of bacteria in feces it was assumed that the presence of a 2000 times greater number of B. hyodysenteriae cells in fecal sample than L. intracellularis did not decrease the sensitivity of multiplex PCR in the detection of L. intracellularis. At the same time about a two times higher amount of L. intracellularis cells than B. hyodysenteriae decreased the sensitivity of multiplex PCR for the detection of B. hyodysenteriae by 200 times. However the presence of porcine feces which contain inhibitory factors decreased the detection of L. intracellularis. Amplification of extracted DNA from feces suspension gave a 100 times lower sensitivity than amplification of extracted DNA from Tris-HCl, pH 8.5 buffer with the same number of CFU/ml L. intracellularis. On the other hand sensitivity of the method was satisfying even if the number of B. hyodysenteriae cells was 2000 times higher. The results proved that multiplex PCR for the detection of B. hyodysenteriae was not susceptible to inhibitory substances, however twice as high a number of L. intracellularis cells than B. hyodysenteriae in a sample hampered the amplification specific to B. hyodysenteriae. The results of this study demonstrated that multiplex PCR is useful for the detection of L. intracellularis. In case of an intensive infection of pigs by both pathogens multiplex PCR has limitations in the diagnosis of B. hyodysenteriae.