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Fatigue damage is commonly encountered by operators of Francis type hydraulic turbine runners made of 13Cr-4Ni soft martensitic stainless steel. These large and complex welded casting assemblies are subjected to fatigue crack initiation and growth in the vicinity of their welded regions. It is well known that fatigue behavior is influenced by residual stresses and the microstructure. By including solid-state phase transformation models in welding simulations, phase distribution can be evaluated along with their respective volumetric change and their effect on residual stresses. Thus, it enables the assessment of welding process on fatigue crack behavior by numerical methods. This paper focuses on modeling solid-state phase transformations of 13Cr-4Ni soft martensitic stainless steel, used for manufacturing hydraulic turbine runners, occurring upon welding. It proposes to determine the material parameters of the models for both the austenitic and the martensitic transformation by nonisothermal dilatometry tests. The experiments are conducted in a quenching dilatometer with applied thermal conditions as experienced in the heat-affected zone of homogeneous welds. The activation energy and the kinetic parameters of the austenitic transformation from fully martensitic state are measured from the experimental results. The martensitic transformation modeling from a fully austenitic domain is also presented.

Climate change has been linked with the establishment and geographical expansion of zoonotic diseases, an example of which is the well-documented increase in human cases of Lyme disease in Quebec, Canada. As temperatures continue to increase in Quebec, it is anticipated that several zoonotic diseases will be affected. In response to the growing zoonotic issues facing public health authorities, Quebec’s Multi-Party Observatory on Zoonoses and Adaptation to Climate Change (Observatoire multipartite québécois sur les zoonoses et l’adaptation aux changements climatiques) (the Observatory) was founded in 2015 as part of the Quebec government’s Climate Change Action Plan (Plan d’action 2013–2020 sur les changements climatiques). The Observatory was designed to bring together agencies involved in formulating public policy and experts from the disciplines of human health, animal health and environmental sciences, in a manner similar to the innovative “One World, One Health” approach. The Observatory provides a platform for knowledge sharing and consensus building among representatives of public policy decision makers and scientists. Its main objectives are to anticipate and prioritize potential issues associated with zoonotic diseases in Quebec, in order to support applicable risk management and climate change adaptation. This article describes what the Observatory is, what it does and outlines its plans for the future.

Coxiella burnetii is a zoonotic agent responsible for human Q fever, a potentially severe disease that can lead to persistent infection. This cross-sectional study aimed to estimate the seroprevalence to C. burnetii antibodies and its association with potential risk factors in the human population of five regions of Québec, Canada. A serum bank comprising sera from 474 dog owners was screened by an enzyme-linked immunosorbent assay followed by confirmation of positive or equivocal sera by an indirect immunofluorescence assay. Observed seroprevalences of 1.2% (95% confidence interval (CI): 0.0–6.6), 2.6% (95% CI: 0.5–7.4) and 5.9% (95% CI: 3.4–9.6) were estimated in the regions of Montréal, Lanaudière and Montérégie, respectively, which all included at least 83 samples. Having lived or worked on a small ruminant farm (prevalence odds ratio (POR) = 5.4; 95% CI: 1.6–17.7) and being a veterinarian or veterinary student (POR = 6.1; 95% CI: 1.6–24.0) were significantly associated with C. burnetii seropositivity. Antibodies against C. burnetii were detected in the human population of Québec. Although seropositivity to this agent was associated with occupational contact with domestic animals, antibodies were also detected in people with no reported professional exposure. No associations with ruminant farm proximity were identified.

Coxiella burnetii is a zoonotic agent responsible for human Q fever, a potentially severe disease that can lead to persistent infection. This cross-sectional study aimed to estimate the seroprevalence to C. burnetii antibodies and its association with potential risk factors in the human population of five regions of Québec, Canada. A serum bank comprising sera from 474 dog owners was screened by an enzyme-linked immunosorbent assay followed by confirmation of positive or equivocal sera by an indirect immunofluorescence assay. Observed seroprevalences of 1.2% (95% confidence interval (CI): 0.0–6.6), 2.6% (95% CI: 0.5–7.4) and 5.9% (95% CI: 3.4–9.6) were estimated in the regions of Montréal, Lanaudière and Montérégie, respectively, which all included at least 83 samples. Having lived or worked on a small ruminant farm (prevalence odds ratio (POR) = 5.4; 95% CI: 1.6–17.7) and being a veterinarian or veterinary student (POR = 6.1; 95% CI: 1.6–24.0) were significantly associated with C. burnetii seropositivity. Antibodies against C. burnetii were detected in the human population of Québec. Although seropositivity to this agent was associated with occupational contact with domestic animals, antibodies were also detected in people with no reported professional exposure. No associations with ruminant farm proximity were identified.

Background: While the contour method for residual stress assessment has developed rapidly, no published study documents its interlaboratory reproducibility. Objective: Here we report an initial reproducibility experiment focused on contour method data analysis and residual stress calculation. Methods: The experiment uses surface topography data from a physical process simulation of elastic-plastic beam bending. The simulation provides surface topography, for input to the contour method data analysis, as well as a known residual stress field with 130MPa peak magnitude. To increase realism, noise and specific artifacts are added to the topography data. A group of participants received the topography data (without the known residual stress), independently analyzed the data, and submitted results as a two-dimensional residual stress field. Results: Analysis of submissions provides a group average residual stress field and the spatial distribution of reproducibility standard deviation. The group average residual stress agrees with the known stress in magnitude and spatial trend. The reproducibility standard deviation ranges from 2 to 54MPa over the measurement plane, with an average of 5.4MPa. Reproducibility standard deviation is smaller in the cross-section interior (≤ 5MPa), modest near local extrema in the stress field (5 to 10MPa), and larger near the cross-section boundaries (10 to 30MPa). The largest values of reproducibility standard deviation (up to 54MPa) occur in limited areas where artifacts had been added to the topography data; while some participants identified and removed these artifacts, some did not, leading to systematic differences that elevated the standard deviation.

Austenitic stainless steel E309L is frequently used for welded repairs on 13%Cr-4%Ni martensitic stainless steel blade runners. However, very high tensile residual stresses are found in the upper layers of these repairs, thus reducing the fatigue resistance of the repaired area in comparison with the free of residual stress base material. The use of hammer peening to increase the fatigue life of E309L welded on UNS-S41500 base metal plates has been investigated using welded samples replicating in situ blade runner repairs. Residual stress measurements using the contour method on these samples have confirmed the high stresses caused by flux cored arc welding (FCAW) of E309L, leaving stress magnitudes close to the ultimate tensile strength of the base material. Hammer peening of the surface beads effectively creates high compressive stresses at the weld’s surface up to 3 mm depth. Alternating bending fatigue tests conducted on hammer peened samples have shown an average life increase of 5.8 times at Sa = 330 MPa over unpeened samples. Fatigue tests have however shown diminishing returns when overpeening the samples.

In this study, an analysis of elastic residual stress in Inconel ® 718 (IN 718) linear friction welds (LFWs) was carried out. In particular, the suitability of LFW for manufacturing and repair of aero engine components was emulated by joining virgin and in-service (extracted from a turbine disk) materials. The evolution in the residual strains and stresses in the heat-affected zone (HAZ), thermomechanically affected zone (TMAZ) and dynamically recrystallized zone (DRX) of the weld was characterized using the neutron diffraction and contour methods. The results provided insight into diverse challenges in quantitative analysis of residual stresses in welded IN 718 using diffraction techniques. Specifically, judicious selection of the beam width, height and stress-free lattice spacing were seen to be crucial to minimize measurement error and increase accuracy. Further, the contour method – a destructive technique relying on capturing the stress relaxation after electrical discharge machining – was used to characterize the residual stress distribution on two-dimensional plane sections of the welds. Both techniques suggested an increasing magnitude of residual stress originating from the base metal that reached a peak at the weld interface. Both methods indicated that the peak magnitude of residual stresses were below the yield stress of IN 718.

In this study, the integrity of electron beam- (EB-) welded CA6NM—a grade of 13% Cr-4% Ni martensitic stainless steel—was assessed through the entire joint thickness of 90 mm after postweld heat treatment (PWHT). The joints were characterized by examining the microstructure, residual stresses, global mechanical properties (static tensile, Charpy impact, and bend), and local properties (yield strength and strain at fracture) in the metallurgically modified regions of the EB welds. The applied PWHT tempered the “fresh” martensite present in the microstructure after welding, which reduced sufficiently the hardness (

UNS S41500 is a grade of 13Cr-4Ni martensitic stainless steel utilized in hydroelectric turbine products. In this study, the microstructural characteristics, mechanical properties, and through-thickness residual stresses of electron-beam (EB) welded butt joints in 90-mm-thick UNS S41500, assembled using a single pass autogenous process, were evaluated after post-weld heat treatment (PWHT). The results of the longitudinal residual stresses, measured using the contour method, indicated that the applied PWHT was effective in stress relieving and reducing the hardness of the weldment through tempering of the “fresh” martensite present in the microstructure after EB welding. The static tensile properties that were evaluated in the directions transverse and longitudinal to the weld seam demonstrated high performance of the joints with conformance to the requirements of not only ASME Section IX, ASME Boiler & Pressure Vessel Code–Section IX: Qualification Standard for Welding and Brazing Procedures, Welders, Brazers, and Welding and Brazing Operators, but also ASTM A240, Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications, for unwelded UNS S41500. The Charpy impact energies indicated that the toughness of the welds greatly surpassed the minimum acceptance criteria specified in ASME Section VIII, ASME Boiler & Pressure Vessel Code–Section VIII: Rules for Construction of Pressure Vessels. Also, bend testing of transverse weld cross sections displayed no discontinuities on the tension side of the bent joints. These results provide the essential data for validating a manufacturing process for assembly of high-performance joints in an important hydroelectric turbine material.

Heavy-section assembly of hydroelectric turbine runner materials using single-pass, autogenous EBW was demonstrated to penetrate a 90-mm-thick butt joint. The welding-induced distortions and residual stresses were characterised to understand the impact of the materials and process conditions (e.g. preheating and/or PWHT). Using 3D optical measurements, the angular distortions of EB-welded UNS S41500 and CA6NM steels were determined to be 0.13° and 0.38°, respectively. The longitudinal residual stresses, measured through the contour method, had a M-shaped distribution throughout the thickness with minimum (∼−500 MPa) compressive stresses in the FZ and maximum (∼600 MPa) tensile stresses in the HAZ. After PWHT, the tensile and compressive stresses reduced to ∼100 MPa.

The original version of this article has been corrected to include authors middle initials in the author list. The details given in this correction are correct.

This paper presents a study on the influence of welding residual stresses (RS) on fatigue crack propagation rate (FCPR) in mode I. The objective of this work is to develop a novel methodology that allows a variation of a RS field in the studied specimen while keeping constant all other variables influencing FCPR. This led to the development of a novel specimen geometry, named CT-RES, in which RS are introduced by weld bead deposition far from the region in which fatigue crack propagation (FCP) occurs. As a consequence, the effect of factors influencing FCPR other than RS such as microstructural changes or plastic deformation, often introduced by welding processes, can be avoided. The welding RS introduced in the CT-RES specimen were determined by the contour method and the weight functions method was used to calculate the stress intensity factor (SIF), K res , resulting from the RS as the fatigue crack propagates into the specimen. The evolution of cyclic stress ratio at the crack tip, Rlocal, was then computed from K res to quantify the influence of RS on the cyclic stress ratio. The results show that for a given stress intensity range, K, the FCPR of the welded geometry with fixed externally low R ratio (R = 0.1), but constantly increasing Rlocal, is the same as for the as-machined geometry without RS, solicited at high cyclic stress ratio (R = 0.7). These observations partially validate the BS7910 standard philosophy in which the remaining life of a flawed structure in presence of tensile RS is calculated from a high cyclic stress ratio (R ≥ 0.5) crack propagation curve to eliminate crack closure effects.

We present the investigation of an outbreak of cercarial dermatitis that occurred in a recreational-tourist lake in the Québec City region (Canada) in the summer of 1999. A case-reporting form was sent to 450 families likely to have activities that would bring them in contact with the lake's water. The snails were characterized and the prevalence of their infestation by schistosomes was investigated. In total, 63 episodes consistent with cercarial dermatitis were reported. Sixty-nine percent of the cases occurred from swimming at the same beach. This location was the one where the only population of snails in the lake was identified. Shoreline residents were informed that they should not feed waterfowl, and a clean-up of the snail population was done at the start of the following summer. There were no cases of cercarial dermatitis at this site the following summer.

This paper presents a stochastic controller, based on an augmented stochastic dynamical model of robot manipulators including noisy flow effects. The model developed allows the regulation of motions of a manipulator subjected to highly variable flow whose effects are modeled as stochastic perturbations. The technique described here should help to stabilize the manipulations in a fluid environment, without the help of an operator. Some results obtained using the present stochastic controller for a manipulator simulated in a wind tunnel, are presented.

Ring-billed gull populations of eastern North America have grown dramatically in the past 30 years. To assess the possible impact of these populations on recreational waters, gull droppings collected at three colonies were examined for fecal coliforms, Aeromonas spp., Campylobacter spp., Pseudomonas aeruginosa, Salmonella spp. and Staphylococcus aureus . The samples were also analyzed for Shigella spp. and Yersinia spp. The samples were collected every two weeks from late April to mid-July. The measured concentrations were compared on the basis of colony, age class and sampling date by analysis of variance (ANOVA) and Fisher’s LSD multiple range test. In general, there was little difference in bacterial content as a function of age groups, colony or sampling date. On the basis of the documented ratios between the various pathogens and total coliforms in the droppings, the limit of 200 fecal coliforms per 100 ml of water used for recreational water quality in Canada provides an acceptable level of protection with respect to contamination by gulls. However, we must qualify these findings by stating that they reflect the situation that existed at the time of sampling, that they apply to a small number of pathogenic microorganisms, and that they do not take into account soil or sand contamination at beaches.

This paper analyzes the current ISO tolerance systems (ISO 286-1 1 and ISO 286-22) and presents new formulas that allow the aggregation of the tolerance system in a simple way. The approach used makes it possible to compute the tolerances in a continuous manner with respect to both dimension and grade of tolerance (quality). The results are always within the tolerances tabulated in the ISO 286-1' and 286-22 Standards. This continuous approach is suitable for optimization in design and automation in tolerancing on computer-assisted design (CAD) systems. The paper proposes a tolerancing approach closer to the modern tolerancing philosophy as given by the Taguchi methods.

Resume Le calcul des forces generees par le mouvement relatif entre un fluide et les membres d'un manipulateur est considere dans cet article. Les integrales donnant la valeur de ces forces ne sont pas evaluables sous forme symbolique par les methodes analytiques et doivent donc etre evaluees par le biais des methodes numeriques. Cette facon de proceder peut entrainer une augmentation importante du temps de calcul pour les applications en temps reel (deux a trois fois le temps normal sans la modelisation de la dynamique des fluides). Afin d'eviter l'accroissement du nombre d'operations a effectuer lors des calculs de dynamique inverse, une nouvelle methode approximative donnant des resultats interessants autant du point de vue temps de calcul que du point de vue precision de l'approximation, est presentee pour remplacer l'integration numerique.

In Nunavik, common practices and food habits such as consumption of raw meat and untreated water place the Inuit at risk for contracting zoonotic diseases. The aim of this study was to determine the seroprevalence of seven zoonotic infections among the permanent residents of Nunavik. The study was conducted in the fall 2004 as part of the Nunavik Health Survey. Blood samples from adults aged 18-74 years (n = 917) were collected and analysed for the presence of antibodies against Trichinella spp., Toxocara canis, Echinococcus granulosus, Brucella spp., Coxiella burnetii, Leptospira spp. and Francisella tularensis. Information on sociodemographic characteristics, traditional activities, drinking water supply and nutrition was gathered using english/inuktitut bilingual questionnaires. The chi-squared test was used to evaluate associations between seropositivity and other measured variables. Statistically significant variables were included in a multivariate logistic regression model to control for confounding factors. Estimated seroprevalences were 8.3% for E. granulosus, 3.9% for T. canis, 5.9% for Leptospira spp. and 18.9% for F. tularensis. Seroprevalence was ≤ 1% for Trichinella spiralis, Brucella spp. and C. burnetii. For most infections, seropositivity tended to increase with age. In multivariate analyses, seroprevalence was positively (i.e. directly) associated with age and residence in the Ungava coast area for F. tularensis; age and residence in the Hudson coast area for T. canis; female gender, lower level of schooling and frequent cleaning of water reservoirs for E. granulosus. No risk factor for Leptospira spp. infection was identified. No associations were detected with regards to food habits or environmental exposures. A small but significant portion of the Nunavik population has serologic evidence of exposure to at least one of the pathogenic microorganisms investigated. Further studies are needed to better understand the mechanisms for transmission of zoonotic infections and their potential reservoirs in Nunavik.

Legionella bacteria ubiquitously colonize natural freshwater and are responsible for legionellosis in humans. Several cases of legionellosis have been associated in particular with the use of whirlpool spas. The objective of this study was to verify whether real-time PCR is applicable for the quantification of Legionella spp. in spa water.The study compared concentrations obtained by real-time PCR vs that obtained by conventional culture for 101 spa water samples. For the culture method, Legionella spp. were detected and quantified in 14 of 101 samples with measured concentrations ranging from 250 to 3.5 × 10(5) CFU l(-1). With the real-time PCR method, Legionella spp. were detected and quantified in 42 of 101 samples with concentrations ranging from 1000 to 6.1 × 10(7) GU l(-1). Results revealed a significant but weak correlation (r(2) = 0.1867) between the two methods. The positive predictive value (35%) of the PCR method compared to conventional culture herein was low. In contrast, the negative predictive value was excellent, reaching 93%.Real-time PCR could be used as a screening tool to rapidly ascertain the absence of Legionella spp. in spa water. However, a positive result involves the need to resort to conventional culture.Data of this study highlighted the pros and cons of quantification of Legionella spp. in spa water with real-time PCR using a commercial quantitative PCR kit in a routine laboratory, when compared to conventional culture.

About 35% of elders living at home fall each year. The objectives of this study were to evaluate the environmental hazards associated with falls in 58 low income housings for elders and to determine the contribution of environmental factors to these falls.Participants were interviewed to document their health problems, their knowledge concerning the Issue of falls, and their history of falls during the last year. Environmental hazards were identified and evaluated with a standardised checklist. The levels of hazards (percentage of factors identified which represent a hazard) were measured for the different sectors and for the entire dwelling and communal spaces. The hazards were also evaluated according to four main variables (structure of the building, characteristics of the floor surface, environmental obstacles, risk-taking behaviour).A total of 172 participants were recruited for the study. For dwellings and communal spaces, the hazards were respectively higher in bathrooms (mean=27.0%; p0.05) and interior stairs (mean=22.5%; p0.05). For the communal spaces of buildings of less than 20 Years, the global hazard was higher in the smaller buildings (or=three stories, mean=14.2%;three stories, mean=12.6%; p0.001). For dwellings of the larger buildings, the global hazard was higher for younger buildings (20 years, mean=16.6%;or=20 years, mean=13.5%; p0.001). Among the variables documented, risk-taking behaviour was the more frequent factor for the dwellings (mean=32.0%; p0.05) as for the communal spaces (mean=42.5%; p0.05). Finally, only 34% of the participants mentioned receiving information concerning the falls among elders. Among the 27 falls documented, an environmental factor was identified in 55% of the cases.The study helped to document the presence of environmental factors which could be a hazard for falls in elders' housing and to suggest preventive and remedial actions.

We analyzed data from the notifiable diseases data base in Québec to document the incidence of giardiasis. The objectives were to perform a descriptive analysis of the cases of giardiasis and to verify the relation between their incidence and the quality of drinking water.The Québec notifiable diseases data-base contained 4273 cases of giardiasis declared between January 1st, 1990 and December 31st, 1995. Incidence rates were adjusted for age and calculated monthly. The sources and kinds of treatment of drinking water permitted to elaborate a vulnerability scale for classifying contamination by Giardia sp. into four categories. Incidence of giardiasis was examined in relation with this vulnerability scale. Other socioeconomic indicators possibly associated with the incidence of giardiasis were also analyzed.Analysis showed that there were few annual variations in the incidence of giardiasis and that there were no epidemic peaks during the study period. According to age, the incidence follows a bimodal pattern with a peak for young children and young adults. The incidence rates showed an increase of the cases at the end of summer and at the beginning of fall, with a higher relative risk for males. Even if no relation was found between the incidence of giardiasis and the vulnerability of the drinking water source, incidence rates were lower for people living in communities that use the St. Lawrence River as a drinking water source than for those using other sources of surface water.This study allowed us to obtain a good description of the cases of giardiasis declared in Québec and to formulate hypothesis about their causes. The lower incidence of giardiasis in communities that use the St. Lawrence river as their drinking water source is possibly related to a lower contamination of this source. However, considering the limits of this work, case-control studies should be considered to understand variables, which influence the incidence of giardiasis in Québec.

The objective of this study was to assess the lung cancer risk resulting from indoor radon exposure in the province of Quebec, Canada, and to evaluate the efficacy of mitigation measures to reduce this exposure. Concentrations of radon were determined in a representative sample of houses, and the corresponding lung cancer risk estimates were generated using the BEIR IV model, taking into account smoking, residential mobility, and regional variations in radon concentrations. Mean (geometric) radon concentrations in basements (n = 418) and on first floors (n = 319) were, respectively, 34.4 (95% CI-30.6 to 38.8) and 16.5 Bq m(-3) (14.2 to 19.3). A total of 109 deaths from lung cancer are predicted to occur as a result of this exposure in a cohort of 60,000 people. Detecting all residences with high radon concentrations (equal to or above 200 Bq m(-3)) and implementing mitigation measures in each of them would reduce by 4 the number of lung cancer deaths attributable to indoor radon exposure. A reduction of 0.05% in the prevalence of smoking would prevent as many deaths from lung cancer as would radon mitigation. From a public health perspective, in order to reduce mortality from lung cancer, most efforts should be focused on smoking, not on the relatively minor and hardly preventable population risk arising from household radon exposure.

In industrialized countries, tobacco smoking is the main cause of preventable morbidity and premature deaths. Although mortality attributable to smoking has already been estimated for the population of the province of Québec, it has never been studied on a regional basis. We calculated the mortality attributable to smoking by socio-sanitary regions of the province of Québec for 10 fatal diseases positively associated with smoking. The calculations were made for the years 1984 through 1993 taking into account Canadian Census data (demographic variables), the Santé-Québec survey (prevalence of smoking), the death registry of the "Bureau de la statistique du Québec" (mortalitry data), and the American cohort of the "Cancer Prevention Study II" (relative risks). For the diseases investigated, 24,637 and 62,711 deaths were attributable to smoking for women and men respectively during the period studied, thus representing 29.4% and 51.2% of attributable percentages. There is no statistical difference between the regions, which indicates a general problem for all the province. These data again confirm the incredible impact of smoking on public health. The struggle against smoking should be a primary area for action for the benefit of all Quebecers.

A pilot study on water consumption was carried out in the Québec City region in April and May 1996 with 125 people using a 24-h recall plus a 2-day diary. Consumption of drinking water via liquid and food was assessed as well as the type of water consumed (tap, bottle or filtered water) and place of consumption (home or away from home). Most of the people (56%) were drinking some bottled water or filtered tap water and 25% of water intake was away from home. Food consumption was found to be a non-significant source of drinking-water intake. The average water consumption was nearly similar in exclusively tap-water consumers and bottled- or filtered-water consumers (1.5 vs. 1.7 l/day, P = 0.29) but two-thirds of the consumption in this last group is natural water, while it is mixed water in the bottled/filtered-water group. No significant difference in amounts consumed were found according to age, but older people drank hot beverages and soup more often. The present pilot-study was weakened by a low participation rate (14%). Incentive might be necessary to improve participation rate and data collection methods must also be simplified. A 24-h recall plus a 1-day diary seem sufficient and data on consumption could be limited to liquids, soups and cereals.

An outbreak of gastroenteritis occurred in a school affecting more than 30% of its 535 students. An epidemiological survey questionnaire was given to all students as well as staff and maintenance personnel. Stool cultures and electronic microscopy were used to detect the presence of a Norwalk-like virus. Several analyses of water samples were also done. This outbreak occurred simultaneously in the two wings of the school (East and South). Those who used the East wing were most affected by the disease (RR = 1.45, CI 95%: 1,14-1,85). There was no indication of food or water supply contamination. A Norwalk-like virus was identified in the stool sample of one child. This along with the clinical characteristics strongly suggested that the pathogen was indeed a Norwalk-like virus. The analysis suggests transmission via contaminated surfaces but also via airborne transport of the infectious agent.

Sera from 108 Cricetomys gambianus (Gambia pouched rat) were investigated for HBV and HAV serum markers. 42.6% of them evidenced anti-HBs and 12.0% anti-HBc. HBs Ag was never detected. The most probable hypothesis is that these animals were infected with a new virus related to HBV.