02325nas a2200217   4500000000100000000000100001008004100002260007000043653002200113653001000135653002800145100001400173700001300187700001900200700001700219700001200236245021600248490000800464520162100472022001402093       2019                            d  c02/2019bSchlütersche Verlagsgesellschaft mbH & Co. KGaHannover10aaerosol infection10aswine10aporcine pleuropneumonia1 aD Hoeltig1 aA Seydel1 aI Hennig-Pauka1 aK-H Waldmann1 aJ Rohde00aIdentification of strain specific differences in incubation periods and distribution of lung lesions between Actinobacillus pleuropneumoniae serotype 2 and serotype 7 after experimental infection of nursery pigs0 v1323 aBackground of this study was to determine whether differences in incubation  period and distribution of lung lesions between different strains of Actinobacillus pleuropneumoniae (A. pleuropneumoniae) exist after the exclusion of influencing  environmental and genetic factors. Therefore a retrospective analysis of four different experimental aerosol infection trials with the same study setup was  done. A total of 120 piglets, aged 7 weeks, from the same farm and the same German Landrace breeding line, were infected either with the A. pleuropneumoniae  serotype 2 strain C3656 or the A. pleuropneumoniae serotype 7 strain AP76 implementing a standardized aerosol infection model. Incubation period, based  upon clinical monitoring, as well as distribution and size of lung lesions dependent on strain, infection dose (high dose: 3x103 cfu/liter aerosol [HD]; low dose:  1x102 cfu/liter aerosol [LD]) and days post infection (day 7/day 20) were assessed. Differences in incubation periods (median C3656 HD: 4.00 hours [h], LD: 8.00 h;  median AP76 HD: 180.00 h, LD: 22.00 h), number of lung lesions (median C3656: 10.00; median AP76: 4.00) and size of lung lesions (median C3656: 2.39; median  AP76 6.93; given as mean of marked score units) were statistically significant between the two strains. Differences were also significant for the number of  lung lesions for AP76 regarding the different infection doses and necropsy days. Therefore strain specific characteristics regarding the examined attributes can be  confirmed. Further studies are needed to reveal the responsible virulence factors and mechanisms.  a0005-9366