[Periodic fever and pancytopenia in a 35-year-old patient]. / Periodisches Fieber und Panzytopenie bei einem 35­jährigen Patienten.

MEDICAL HISTORY AND INITIAL PRESENTATION: A 35-year-old patient with a previous history of persistent episodic fever, sore throat, myalgia, and cephalgia presented for evaluation of pancytopenia. He had no recent travel history, except for a stay in Italy 1 year prior to admission and in Spain several years in the past. DIAGNOSTIC WORKUP: Laboratory evaluation confirmed pancytopenia, agranulocytosis, and elevated infection parameters without indicative serological results en par with lymphadenitis colli. Computed tomography scanning revealed cervical lymphadenopathy, hepatosplenomegaly, and colitis with occult perforation of the sigmoid colon. Bone marrow biopsy showed an infiltration of polyclonal plasma cells. Lymph node biopsy was compatible with necrotizing lymphadenitis. DIAGNOSIS: Polymerase chain reaction analysis of a lymph node specimen confirmed the presence of Leishmania species, thereby enabling the diagnosis of visceral Leishmania. THERAPY COURSE: Treatment with liposomal amphotericin B was initiated. Both fever and lymphadenopathy quickly resolved. CONCLUSION: VL is a clinically pleiotropic, severe disease with fatal outcome if left untreated. It often presents with distinct similarities to hematologic malignancies. Exacerbation can occasionally occur as fulminant macrophage activation syndrome. Disease incidence is globally increasing and has not peaked as yet. A complex interplay between pathogen and the immune system is the key pathophysiological mechanism.

Validated quantitative trait loci for eggshell quality in experimental and commercial laying hens.

Compromised eggshell quality causes considerable economic losses for the egg industry. Breeding for improved eggshell quality has been very challenging. Eggshell quality is a trait that would greatly benefit from marker-assisted selection, which would allow the selection of sires for their direct contribution to the trait and would also allow implementation of measurements integrating a number of shell parameters that are difficult to measure. In this study, we selected the most promising autosomal quantitative trait loci (QTL) affecting eggshell quality on chromosomes 2, 3, 6 and 14 from earlier experiments and we extended the F2 population to include 1599 F2 females. The study was repeated on two commercial populations: Lohmann Tierzucht Rhode Island Red line (n = 692 females) and a Hy-Line White Plymouth Rock line (n = 290 progeny tested males). We analyzed the selected autosomal QTL regions on the three populations with SNP markers at 4-13 SNPs/Mb density. QTL for eggshell quality were replicated on all studied regions in the F2 population. New QTL were detected for eggshell color on chromosomes 3 and 6. Marker associations with eggshell quality traits were validated in the tested commercial lines on chromosomes 2, 3 and 6, thus paving the way for marker-assisted selection for improved eggshell quality.

Mixing Block Copolymers with Phospholipids at the Nanoscale: From Hybrid Polymer/Lipid Wormlike Micelles to Vesicles Presenting Lipid Nanodomains.

Hybrids, i.e., intimately mixed polymer/phospholipid vesicles, can potentially marry in a single membrane the best characteristics of the two separate components. The ability of amphiphilic copolymers and phospholipids to self-assemble into hybrid membranes has been studied until now on the submicrometer scale using optical microscopy on giant hybrid unilamellar vesicles (GHUVs), but limited information is available on large hybrid unilamellar vesicles (LHUVs). In this work, copolymers based on poly(dimethylsiloxane) and poly(ethylene oxide) with different molar masses and architectures (graft, triblock) were associated with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Classical protocols of LUV formation were used to obtain nanosized self-assembled structures. Using small-angle neutron scattering (SANS), time-resolved Förster resonance energy transfer (TR-FRET), and cryo-transmission electron microscopy (cryo-TEM), we show that copolymer architecture and molar mass have direct influences on the formation of hybrid nanostructures that can range from wormlike hybrid micelles to hybrid vesicles presenting small lipid nanodomains.

Genetic parameters of egg quality traits on different pedigree layers with special focus on dynamic stiffness.

Egg quality traits are of utmost importance in layer breeding programs due to their effect on profitability in the egg production industry and on the production of quality chicks. Therefore, the aim of this study was to analyze and estimate genetic parameters of different quality traits: egg weight, breaking strength, dynamic stiffness (Kdyn), egg shape index, eggshell thickness, and albumen height. Eggs were obtained from 4 pure lines of birds. Two different tests were performed: a white breeding program, with eggs from a male and female line of a white egg layer program that were analyzed at 67 to 70 wk of age, and a brown breeding program, with eggs from a male and female line of a brown egg layer program that were analyzed at 32 to 36 wk of age. In general, heritabilities were moderate to high for all traits (h² = 0.23 to 0.71). A high genetic correlation was estimated in both tests between breaking strength and Kdyn (rg = +0.40 to +0.61). Shell thickness was also positively correlated with breaking strength (rg = +0.50 to +0.63) and Kdyn (rg = +0.28 to +0.69). These moderate relationships demonstrate that the strength of an egg not only relies on the shell thickness but also on the quality and uniformity of eggshell construction. Dynamic stiffness might be preferred for breeding purposes due to its lower negative genetic correlation with egg weight and its higher heritability (h² = 0.35 to 0.70) compared with breaking strength (h² = 0.23 to 0.35). Breaking strength and Kdyn were positively correlated with shape index, which confirms that round eggs will show higher shell stability. Therefore, it is necessary to monitor egg shape to maintain an optimal form.

Implications of genetic selection on yolk proportion on the dry matter content of eggs in a White Leghorn population.

1. The responses to genetic selection on yolk proportion as a technique for increasing egg dry matter content, an important criterion for the egg-product industry, was investigated in a pedigree flock of White Leghorn hens. 2. Parents were preselected on high and low yolk proportion from a base population. The absolute estimated breeding value for yolk proportion of both groups differed by 3%. The realised selection difference in dry matter content of eggs between groups was more than 1% in the analysed offspring population. 3. Heritability estimates were moderate and dry matter had a lower heritability (h(2) = 0.39) than yolk proportion (h(2) = 0.44). 4. The genetic correlation between yolk proportion and dry matter content was highly positive (rg = 0.91). Genetic correlations with egg weight were negative and would have to be compensated for in a breeding programme (rg = -0.76 with yolk proportion and rg = -0.64 with dry matter content). The genetic correlation between the laying performance and yolk proportion was rg = 0.28 and close to zero (rg = -0.05) for dry matter content. 5. Easy recording and lower undesirable correlations make yolk proportion more suitable for commercial selection compared with egg dry matter content in layer breeding.

Ilioinguinal and iliohypogastric nerves cannot be selectively blocked by using ultrasound guidance: a volunteer study.

BACKGROUND: Ilioinguinal (IL) and iliohypogastric (IH) nerve blocks are used in patients with chronic postherniorrhaphy pain. The present study tested the hypothesis that our method, previously developed in cadavers, blocks the nerves separately and selectively in human volunteers. METHODS: We blocked the IL and the IH nerves in 16 volunteers in a single-blinded randomized cross-over setting under direct ultrasound visualization, by injecting two times the ED95 volume of 1% mepivacaine needed to block a peripheral nerve. The anaesthetized skin areas were tested by pinprick and marked on the skin. A digital photo was taken. For further analysis, the parameterized picture data were transformed into a standardized and unified coordinate system to compare and calculate the overlap of the anaesthetized skin areas of the two nerves on each side. An overlap <25% was defined as selective block. RESULTS: Fifty nerve blocks could be analysed. The mean volume injected to block a single nerve was 0.9 ml. Using ultrasound, we observed spread from one nerve to the other in 12% of cases. The overlap of the anaesthetized skin areas of the nerves was 60.3% and did not differ after exclusion of the cases with visible spread of local anaesthetic from one nerve to the other. CONCLUSIONS: The IL and IH nerves cannot be selectively blocked even if volumes below 1 ml are used. The most likely explanation is the spread of local anaesthetic from one nerve to the other, although this could not be directly observed in most cases.

Enhancing the egg's natural defence against bacterial penetration by increasing cuticle deposition.

The cuticle is a proteinaceous layer covering the avian egg and is believed to form a defence to microorganism ingress. In birds that lay eggs in challenging environments, the cuticle is thicker, suggesting evolutionary pressure; however, in poultry, selection pressure for this trait has been removed because of artificial incubation. This study aimed to quantify cuticle deposition and to estimate its genetic parameters and its role on trans-shell penetration of bacteria. Additionally, cuticle proteins were characterised to establish whether alleles for these genes explained variation in deposition. A novel and reliable quantification was achieved using the difference in reflectance of the egg at 650 nm before and after staining with a specific dye. The heritability of this novel measurement was moderate (0.27), and bacteria penetration was dependent on the natural variation in cuticle deposition. Eggs with the best cuticle were never penetrated by bacteria (P < 0.001). The cuticle proteome consisted of six major proteins. A significant association was found between alleles of one of these protein genes, ovocleidin-116 (MEPE), and cuticle deposition (P = 0.015) and also between alleles of estrogen receptor 1 (ESR1) gene and cuticle deposition (P = 0.008). With the heritability observed, genetic selection should be possible to increase cuticle deposition in commercial poultry, so reducing trans-generational transmission of microorganisms and reversing the lack of selection pressure for this trait during recent domestication.

Higher precision level at individual laying performance tests in noncage housing systems.

With the Weihenstephan funnel nest box, 12 laying hen flocks were tested for their individual laying performance, egg quality, and nesting behavior in a noncage environment. During the whole observation period of 8 yr, a transponder-based data recording system was continuously improved and resulted in a recording accuracy of 97%. At peak production, heritabilities for the number of eggs laid are in some flocks higher than expected. With improved data accuracy, heritability estimates on individual egg weights are more stable. Heritabilities for nesting behavior traits range between a low to moderate level, providing very useful information for laying hen selection to help improve traits that cannot be recorded in cages. Over the years, the benefits of the Weihenstephan funnel nest box for laying hen breeders have grown. This is due to higher data recording accuracies and extended testing capacities, which result in more reliable genetic parameters.

An analysis of the maxillary beak shape variation between 2 pure layer lines and its relationship to the underlying premaxillary bone, feather cover, and mortality.

Beak shape varies considerably within and between intact-beak laying hens, and aspects of beak shape appear to be heritable. As an alternative to beak treatment (an effective method of reducing damage from severe feather pecking (SFP)), this variation could be used to genetically select hens whose beak shapes are less apt to cause damage. To be able to select certain phenotypes, the beak shape variation that exists within laying hen flocks must first be characterized. The objectives of this study were to 1) describe the maxillary beak shape variation in 2 pure White Leghorn layer lines with intact beaks using geometric morphometrics to analyze images, and 2) examine the beak shape's relationship to the premaxillary bone, feather cover, and mortality. A lateral head image was taken of each hen (n = 710), and 20 landmarks were placed along each image's dorsal and ventral margins of the maxillary beak. Landmark coordinates were standardized by Procrustes superimposition, and the covariation was analyzed by principal components analysis and multivariate regression. Feather cover was scored at 3 ages and mortality was monitored throughout the production cycle. Three principal components (PCs) explained 83% of the maxillary beak shape variation and the first PC partially separated the 2 lines. Maxillary beak shapes ranged from long and narrow with pointed tips to short and wide with more curved tips. Moderate correlations were found between the maxillary beak and premaxillary bone shape (rs = 0.44) and size (rs = 0.52). Line A hens had better feather cover than Line B at all ages. Line A hens also had less total and cannibalism-related mortality than Line B (10.7 and 0.4% vs. 16.7 and 2.4%, respectively). Beak shape may be one factor contributing to the observed differences in feather cover and mortality. The results suggest that distinct maxillary beak phenotypes within each line could be selected to help reduce SFP damage and improve bird welfare.

From chain collapse to new structures: spectroscopic properties of poly(3-thiophene acetic acid) upon binding by alkyl trimethylammonium bromide surfactants.

The binding of cationic surfactants with varying alkyl chain length to a regiorandom conjugated polyanion, poly(3-thiophene acetic acid) (PTAA), is studied in an aqueous buffer by using absorption and emission spectroscopies, photon correlation spectroscopy, isothermal titration calorimetry, and cryogenic transmission electron microscopy. We study the mixed solutions as a function of composition ratio R of surfactant molecules to monomer units molar concentrations, at low polymer concentration and in a very wide composition range (10(-6) < R < 10(2)) below the critical micellar concentration. Upon surfactant binding, the molecularly dispersed chains first collapse progressively and then form new structures as the mixed aggregates get enriched in surfactant. The collapse leads to a strong decrease of the conjugation length and to a blue shift of the absorption spectra by 30 to 50 nm. The new structures are responsible for a new intense emission band at about 600 nm, red-shifted by nearly 130 nm from the initial emission maximum of the polymer (~472 nm). As the surfactant tail becomes shorter, the blue shift of the absorption spectra and the intensity raise of the new emission are delayed to larger composition ratios while their variations become smoother functions of the surfactant concentration. These particular spectroscopic properties of PTAA seem related to its unique combination of a strongly hydrophobic backbone, a large ratio of contour length to persistence length, and an overall good aqueous solubility. Our results show that such features are well suited to design a colorimetric biosensor at small composition ratio, and a fluorescent biomarker at large composition ratio.

Genetic variation in eggshell crystal size and orientation is large and these traits are correlated with shell thickness and are associated with eggshell matrix protein markers.

The size and orientation of calcium carbonate crystals influence the structure and strength of the eggshells of chickens. In this study, estimates of heritability were found to be high (0.6) for crystal size and moderate (0.3) for crystal orientation. There was a strong positive correlation (0.65) for crystal size and orientation with the thickness of the shell and, in particular, with the thickness of the mammillary layer. Correlations with shell breaking strength were positive but with a high standard error. This was contrary to expectations, as in man-made materials smaller crystals would be stronger. We believe the results of this study support the hypothesis that the structural organization of shell, and in particular the mammillary layer, is influenced by crystal size and orientation, especially during the initial phase of calcification. Genetic associations for crystal measurements were observed between haplotype blocks or individual markers for a number of eggshell matrix proteins. Ovalbumin and ovotransferrin (LTF) markers for example were associated with crystal size, while ovocleidin-116 and ovocalyxin-32 (RARRES1) markers were associated with crystal orientation. The location of these proteins in the eggshell is consistent with different phases of the shell-formation process. In conclusion, the variability of crystal size, and to a lesser extent orientation, appears to have a large genetic component, and the formation of calcite crystals are intimately related to the ultrastructure of the eggshell. Moreover, this study also provides evidence that proteins in the shell influence the variability of crystal traits and, in turn, the shell's thickness profile. The crystal measurements and/or the associated genetic markers may therefore prove to be useful in selection programs to improve eggshell quality.

Quantitative trait loci affecting eggshell traits in an F(2) population.

Good eggshell quality is important for both table egg quality and chicken reproductive performance. Weak eggshells cause economic losses in all production steps. Poor eggshell quality also poses increased risk for Salmonella infections. Eggshell quality has been a difficult trait to improve by traditional breeding, as it can be measured only for females and it is difficult and expensive to measure. Breeding for improved shell quality may therefore benefit from the use of marker-assisted selection. In an effort to find markers linked to eggshell quality, we have used an F(2) population of 668 females to map quantitative trait loci (QTL) affecting eggshell traits (eggshell deformation, breaking force, weight). By using 160 microsatellite markers on 27 chromosomes, we found 11 genome-wide and 15 suggestive QTL for shell traits measured at different times during production. Loci affecting the deformation were found on chromosomes 1, 2, 6, 10, 14 and Z. Loci affecting the breaking force were detected on chromosomes 2, 3, 10, 12 and Z. Loci affecting the shell weight were detected on chromosomes 6, 12, 24 and Z. Each QTL explains between 1.5% and 4.6% of the phenotypic variance, adding up to 10-15% of total phenotypic variance explained for the different traits. No epistatic effects were observed between loci affecting eggshell traits. Because the effects for quality are mainly additive, these results provide a basis for further characterization of the loci to identify closely linked markers to be used in marker-assisted selection.

Determining the variation in premaxillary and dentary bone morphology that may underlie beak shape between two pure layer lines.

Beak treatment is an effective method of reducing the damage inflicted by severe feather pecking (SFP) but there is significant pressure to eliminate these treatments and rely solely on alternative strategies. Substantial variation in beak shape exists within non-beak treated layer flocks and beak shape appears to be heritable. There is the potential to use this pre-existing variation and genetically select for hens whose beak shapes are less apt to cause damage during SFP. To do this, we must first understand the range of phenotypes that exist for both the external beak shape and the bones that provide its structure. The objective of this study was to determine the variation in premaxillary (within the top beak) and dentary (within the bottom beak) bone morphology that exists in 2 non-beak treated pure White Leghorn layer lines using geometric morphometrics to analyze radiographs. Lateral head radiographs were taken of 825 hens and the premaxillary and dentary bones were landmarked. Landmark coordinates were standardized by Procrustes superimposition and the covariation was analyzed by principal components analysis and multivariate regression using Geomorph (an R package). Three principal components (PCs) explained 85% of total premaxillary bone shape variation and showed that the shape ranged from long and narrow with pointed bone tips to short and wide with more curved tips. Two PCs explained 81% of total dentary bone shape variation. PC1 described the dentary bone length and width and PC2 explained the angle between the bone tip and its articular process. For both bones, shape was significantly associated with bone size and differed significantly between the two lines. Bone size accounted for 42% of the total shape variation for both bones. Together, the results showed a range of phenotypic variation in premaxillary and dentary bone shape, which in turn may influence beak shape. These bone phenotypes will guide further quantitative genetic and behavioral analyses that will help identify which beaks shapes cause the least damage when birds engage in SFP.

Evaluation of inbreeding in laying hens by applying optimum genetic contribution and gene flow theory.

Due to consistent increases of inbreeding of on average 0.95% per generation in layer populations, selection tools should consider both genetic gain and genetic relationships in the long term. The optimum genetic contribution theory using official estimated breeding values for egg production was applied for 3 different lines of a layer breeding program to find the optimal allocations of hens and sires. Constraints in different scenarios encompassed restrictions related to additive genetic relationships, the increase of inbreeding, the number of selected sires and hens, and the number of selected offspring per mating. All these constraints enabled higher genetic gain up to 10.9% at the same level of additive genetic relationships or in lower relationships at the same gain when compared with conventional selection schemes ignoring relationships. Increases of inbreeding and genetic gain were associated with the number of selected sires. For the lowest level of the allowed average relationship at 10%, the optimal number of sires was 70 and the estimated breeding value for egg production of the selected group was 127.9. At the highest relationship constraint (16%), the optimal number of sires decreased to 15, and the average genetic value increased to 139.7. Contributions from selected sires and hens were used to develop specific mating plans to minimize inbreeding in the following generation by applying a simulated annealing algorithm. The additional reduction of average additive genetic relationships for matings was up to 44.9%. An innovative deterministic approach to estimate kinship coefficients between and within defined selection groups based on gene flow theory was applied to compare increases of inbreeding from random matings with layer populations undergoing selection. Large differences in rates of inbreeding were found, and they underline the necessity to establish selection tools controlling long-term relationships. Furthermore, it was suggested to use optimum genetic contribution theory for conservation schemes or, for example, the experimental line in our study.

Polymorphisms in eggshell organic matrix genes are associated with eggshell quality measurements in pedigree Rhode Island Red hens.

Novel and traditional eggshell quality measurements were made from up to 2000 commercial pedigree hens for a candidate gene association analysis with organic eggshell matrix genes: ovocleidin-116, osteopontin (SPP1), ovocalyxin-32 (RARRES1), ovotransferrin (LTF), ovalbumin and ovocalyxin-36, as well as key genes in the maintenance and function of the shell gland [estrogen receptor (ESR1) and carbonic anhydrase II (CAII)]. Associations were found for (i) ovalbumin with breaking strength and shell thickness; (ii) ovocleidin-116 with elastic modulus, shell thickness and egg shape; (iii) RARRES1 with mammillary layer thickness; (iv) ESR1 with dynamic stiffness; (v) SPP1 with fracture toughness and (vi) CAII with egg shape. The marker effects are as large as 17% of trait standard deviations and could be used to improve eggshell quality.

Breeding to reduce susceptibility to Escherichia coli in layers.

Colibacillosis is a bacterial disease of great concern in the layer industry causing substantial animal and economic losses worldwide. Breeding for resistance to colibacillosis is an important control strategy that would complement traditional management strategies such as vaccinations and therapeutic treatments. Because antibiotic use in animal production is expected to substantially decrease in the future to meet not only consumer demands but also regulations, it is expected that bacterial diseases such as colibacillosis will become even more important. A challenge test was carried out on 353 pedigreed White Leghorn female chickens of 1 pure line. The birds were inoculated with Escherichia coli at an age of 93 to 95 wk (3 hatches) and symptoms of disease and mortality were constantly monitored for up to 6 d after inoculation. The cumulative mortality was 64%, the majority of which took place in the first 2 d. In the present study, genetic parameters of resistance to colibacillosis were estimated to judge the value of genetic selection. The heritability for survival rate was 0.17+/-0.07. Both for quantitative as well as for qualitative traits of economic interest, there was no remarkable difference between survivors and hens that died. Data showed that it is in principle possible to breed for colibacillosis resistance without penalizing the improvement in other key traits. The B21 marker for MHC in this study was associated with a lower colibacillosis susceptibility. In this study, it was demonstrated that it is possible to breed for Escherichia coli resistance. However, due to the inconveniences of a challenge test, it would be very interesting to make use of MAS.

[Dissociative seizures: a diagnostic and therapeutic challenge on the borderline between psychiatry and neurology]. / Dissoziative Anfälle : Eine diagnostische und therapeutische Herausforderung im Grenzbereich von Psychiatrie und Neurologie.

Dissociative seizures, albeit a psychiatric symptom, are encountered only rarely in psychiatric settings and more often in a neurologic context. Due to the clinical similarity of these dissociative states with neurological symptoms, optimal treatment is often hampered and lies on the border between psychiatric and neurologic approaches. Diagnostic work-up as well as the therapy may prove to be complex and tedious, partly due to the underlying psychopathology of these patients. Management by neurologists, psychiatrists, and primary care physicians should take into account specific therapeutic and diagnostic guidelines aimed at improving outcome and minimizing the negative social and occupational effect which often burden these patients.

Epilepsy, hyperalgesia, impaired memory, and loss of pre- and postsynaptic GABA(B) responses in mice lacking GABA(B(1)).

GABA(B) (gamma-aminobutyric acid type B) receptors are important for keeping neuronal excitability under control. Cloned GABA(B) receptors do not show the expected pharmacological diversity of native receptors and it is unknown whether they contribute to pre- as well as postsynaptic functions. Here, we demonstrate that Balb/c mice lacking the GABA(B(1)) subunit are viable, exhibit spontaneous seizures, hyperalgesia, hyperlocomotor activity, and memory impairment. Upon GABA(B) agonist application, null mutant mice show neither the typical muscle relaxation, hypothermia, or delta EEG waves. These behavioral findings are paralleled by a loss of all biochemical and electrophysiological GABA(B) responses in null mutant mice. This demonstrates that GABA(B(1)) is an essential component of pre- and postsynaptic GABA(B) receptors and casts doubt on the existence of proposed receptor subtypes.

Analysis of the free range behaviour of laying hens and the genetic and phenotypic relationships with laying performance.

1. Over twelve 28-d laying periods (almost one year), 272 laying hens of the Lohmann Silver strain, individually tagged with transponders, were monitored on their ranging behaviour and laying performance in an aviary system with an adjacent winter garden. 2. From laying periods 1 to 12, the daily frequency of passages between the barn and the winter garden of individual hens, showed an antagonistic trend compared to the average duration of single visits. While the frequency of passages decreased until the end of the recording period to 8 passages per hen and day, the average duration of single visits increased to a maximum of 32 min per hen. 3. The heritability estimates for the traits, length of stay in the winter garden and frequency of passages were higher for the last 5 laying periods than at the beginning of the recording period. For the last 5 laying periods, the estimates for the duration of stay in the winter garden varied between h(2) = 0.21 and 0.32 and for the frequency of passages, between h(2) = 0.30 and 0.49. 4. Most of the estimated heritabilities for the rate of lay were on an expected medium level (h(2) = 0.09 to 0.45). Deviant h(2)-values to a few laying periods were based on low additive genetic variances or high environmental variance. 5. Genetic correlations between both free range traits and the laying performance were negative (r(g length of stay) = -0.34 and r(g passage frequency) = -0.08). 6. Generally, there seems to be a possibility to influence the ranging behaviour through selection. Further investigations with different genotypes and varying dates of exposure to the laying environment, should be carried out to clarify possible influences on other traits and the negative correlation with laying performance.

Genetic approach to select against embryo mortality caused by Enterococcus faecalis infection in laying hens.

Selection to reduce susceptibility to Enterococcus faecalis infection in laying hens may contribute to the prevention of amyloid arthropathy since it is mainly induced by this bacterium. Therefore, the aim of the present study was to investigate the possibility to select more laying hens that are resistant against E. faecalis infection through the embryo lethality assay (ELA), which is proposed as an alternative model to replace the adult avian challenge assay. Ten-day-old embryos of 500 Lohmann Brown layers were inoculated into the allantoic cavity with an infectious dose of 2.5 colony-forming units (cfu)/mL of the avian E. faecalis strain K923/96 in 3 ELAs. The embryonic mortality rate (EMR) was determined by candling the eggs daily over a period of 4 d. The average EMR estimated during the 3 ELAs was 50% and the highest EMR occurred 3 to 4 d post inoculation. The estimated heritability for embryonic survivability to the infection was h2 = 0.12-0.14, calculated with the logistic and probit link function, respectively, indicating that the selection of more laying hens that are resistant to E. faecalis infection is feasible. A highly negative genetic correlation was estimated between embryonic survivability and laying performance at the peak of lay (rg = -0.22) and at the end of the production (rg = -0.65), as well as with breaking strength (rg = -0.30 to -0.37). A positive correlation was found between egg weight and the embryonic survivability (rg = +0.16), and no genetic correlation was found with body weight and dynamic stiffness. Therefore, although it was demonstrated that it is possible to breed for E. faecalis resistance, special care should be taken to monitor and to take all traits and their genetic correlations into account in order to achieve a balanced genetic progress. Besides, the ELA does not require that the hens are exposed to pathogens thereby saving labor and cost. Therefore, it could be feasible that ELA be implemented in selection programs.