2. Universidad Cardenal Herrera-CEU

Listeria monocytogenes is a major human and animal foodborne patho-gen. However, data from environmental reservoirs remain scarce. Here, we usedwhole-genome sequencing to characterize Listeria species isolates recovered over 1year from wild animals in their natural habitats in Spain. Three different Listeria spp.(L. monocytogenes [n = 19], Listeria ivanovii subsp. londoniensis [n = 4], and Listeriainnocua [n = 3]) were detected in 23 animal tonsils (9 deer, 14 wild boars) and 2feeding troughs. No Listeria species was detected in feces. L. monocytogenes wasdetected in tonsils of 44.4% (8 out of 18) of deer and 40.7% (11 out of 27) of wildboars. L. monocytogenes isolates belonged to 3 different core genome multilocussequence typing (cgMLST) types (CTs) of 3 distinct sublineages (SL1, SL387, andSL155) from lineages I and II. While cgMLST type L1-SL1-ST1-CT5279 (IVb; clonalcomplex 1 [CC1]) occurred only in one animal, types L1-SL387-ST388-CT5239 (IVb;CC388) and L2-SL155-ST155-CT1170 (IIa; CC155) were retrieved from multiple ani-mals. In addition, L1-SL387-ST388-CT5239 (IVb; CC388) isolates were collected 1 yearapart, revealing their long-term occurrence within the animal population and/orenvironmental reservoir. The presence of identical L. monocytogenes strains in deerand wild boars suggests contamination from a common food or environmentalsource, although interhost transmission cannot be excluded. Pathogenicity islandsLIPI-1, LIPI-3, and LIPI-4 were present in 100%, 5%, and 79% of the L. monocytogenesisolates, respectively, and all L. monocytogenes lineage II isolates (n = 3) carried SSI-1stress islands. This study highlights the need for monitoring L. monocytogenes envi-ronmental contamination and the importance of tonsils as a possible L. monocyto-genes intrahost reservoir.

Leishmaniasis is a zoonotic parasitic disease, and the main reservoir of the parasite is the dog, although recent years have seen an increase in other mammalian species. In the Mediterranean region, where it is an endemic disease, it is caused by the species Leishmania infantum. The Ibizan hound, an autochthonous breed of this region, appears to have a genetic resistance to parasitic infection, whereas other canine breeds, such as the Boxer, are susceptible to infection. These differences are related to the differentiated activation of the immune response, with the Ibizan hound activating the Th1 immune response, whereas the Boxer breed triggers the Th2 immune response. Cytokine levels and genomic haplotypes of several genes involved in the immune response were analysed in twenty-eight Ibizan hound (resistant canine breed model) and twenty-four Boxer (susceptible canine breed) without clinical signs in the Mediterranean region. Cytokine levels were analysed by ELISA commercial kits and haplotypes were studied using CanineHD DNA Analysis BeadChip including 165,480 mapped positions. The results show 126 haplotypes associated with differential immune response in dogs. Specifically, haplotypes in IL12RB1, IL6R, CIITA, THEMIS, NOXA1, HEY2, RAB38, SLC35D2, SLC28A3, RASEF and DAPK1 genes are associated with serum levels of IFN-γ, IL-2, IL-8, and IL-18. These results suggest that the resistance or susceptibility to Leishmania infantum infection could be a consequence of haplotypes in several genes related to immune response. Future studies are needed to elucidate the relationship of these haplotypes with immune response and gene expression regulation.

The aim of the work was to evaluate if genetic selection for daily gain may affect the immune system. Two experiments were performed. The first one involved 80 rabbit females and their first two litters to explore the effect of selection on the ability of animals to maintain immune competence. Two generations from a line selected for average daily gain (ADG) were evaluated (VR19 generation 19th, n = 43; VR37 generation 37th, n = 37). In females, the effect of selection and its interaction with physiological state were not significant for any trait. In litters, the selection criterion increased the granulocyte to lymphocyte ratio. The second experiment involved 73 19-week-old females (VR19, n = 39; VR37, n = 34) to explore the effect of genetic selection on immune response after S. aureus infection. The VR37 rabbit females had lower counts for total lymphocytes, CD5+, CD4+, CD8+, CD25+, monocytes, the CD4+/CD8+ ratio and platelets than those of VR19 (-14, -21, -25, -15, -33, -18, -11 and -11%, respectively; P < 0.05). VR37 had less erythema (-8.4 percentage points; P < 0.05), fewer nodules (-6.5 percentage points; P < 0.05) and a smaller nodule size (-0.65 cm3 on 7 day post-inoculation; P < 0.05) compared to VR19. Our study suggests that genetic selection for average daily gain does not negatively affect the maintenance of a competent immune system or the ability to establish immune response. It seems that such selection may improve the response to S. aureus infections.