PFAS levels and determinants of variability in exposure in European teenagers - Results from the HBM4EU aligned studies (2014-2021).

BACKGROUND: Perfluoroalkyl substances (PFAS) are man-made fluorinated chemicals, widely used in various types of consumer products, resulting in their omnipresence in human populations. The aim of this study was to describe current PFAS levels in European teenagers and to investigate the determinants of serum/plasma concentrations in this specific age group. METHODS: PFAS concentrations were determined in serum or plasma samples from 1957 teenagers (12-18 years) from 9 European countries as part of the HBM4EU aligned studies (2014-2021). Questionnaire data were post-harmonized by each study and quality checked centrally. Only PFAS with an overall quantification frequency of at least 60% (PFOS, PFOA, PFHxS and PFNA) were included in the analyses. Sociodemographic and lifestyle factors were analysed together with food consumption frequencies to identify determinants of PFAS exposure. The variables study, sex and the highest educational level of household were included as fixed factors in the multivariable linear regression models for all PFAS and each dietary variable was added to the fixed model one by one and for each PFAS separately. RESULTS: The European exposure values for PFAS were reported as geometric means with 95% confidence intervals (CI): PFOS [2.13 µg/L (1.63-2.78)], PFOA ([0.97 µg/L (0.75-1.26)]), PFNA [0.30 µg/L (0.19-0.45)] and PFHxS [0.41 µg/L (0.33-0.52)]. The estimated geometric mean exposure levels were significantly higher in the North and West versus the South and East of Europe. Boys had significantly higher concentrations of the four PFAS compared to girls and significantly higher PFASs concentrations were found in teenagers from households with a higher education level. Consumption of seafood and fish at least 2 times per week was significantly associated with 21% (95% CI: 12-31%) increase in PFOS concentrations and 20% (95% CI: 10-31%) increase in PFNA concentrations as compared to less frequent consumption of seafood and fish. The same trend was observed for PFOA and PFHxS but not statistically significant. Consumption of eggs at least 2 times per week was associated with 11% (95% CI: 2-22%) and 14% (95% CI: 2-27%) increase in PFOS and PFNA concentrations, respectively, as compared to less frequent consumption of eggs. Significantly higher PFOS concentrations were observed for participants consuming offal (14% (95% CI: 3-26%)), the same trend was observed for the other PFAS but not statistically significant. Local food consumption at least 2 times per week was associated with 40% (95% CI: 19-64%) increase in PFOS levels as compared to those consuming local food less frequently. CONCLUSION: This work provides information about current levels of PFAS in European teenagers and potential dietary sources of exposure to PFAS in European teenagers. These results can be of use for targeted monitoring of PFAS in food.

[Quantitative classification of pivot-shift maneuver]. / Clasificación cuantitativa de la maniobra de pivot-shift.

INTRODUCTION: The diagnosis of ACL injury is established with the physical examination that includes the Lachman maneuver and the pivot-shift test since it has the highest positive predictive value. Imaging tests such as MRI are still used for confirmation of the same; so the quantification of clinical maneuvers is sought. MATERIAL AND METHODS: Prospective clinical study in which the maneuvers of pivot-shift and Lachman are quantified for later classification. RESULTS: Of 36 patients, 64% found a range between 0 and 3 mm when subtracting the value of the affected knee from the value of the healthy knee. It was found that 28% of the patients recorded values of KT-1000 ranging between 4 and 6 mm of displacement. In 8% of the total patients, values of KT-1000 were found that exceeded 7 mm of displacement. The data obtained are normalized and classified into 3 degrees of injury: grade 1 with partial injury; grade 2 with complete anteromedial and partial injury in posterolateral bundle; grade 3 with complete injury of both bundles. CONCLUSION: A classification is proposed for the degrees of ACL injury with future application to a more personalized reconstruction.

INTRODUCCIÓN: El diagnóstico de lesión del ligamento cruzado anterior se establece con la exploración física que incluya la maniobra de Lachman y la prueba de pivot-shift, ya que cuenta con el mayor valor predictivo positivo. Aún se recurre a pruebas de gabinete como la RMN para la confirmación del mismo; por lo que se busca la cuantificación de maniobras clínicas. MATERIAL Y MÉTODOS: Estudio clínico prospectivo en el que se cuantifican las maniobras de pivot-Shift y Lachman para su posterior clasificación. RESULTADOS: De 36 pacientes, 64% se encontró un rango entre 0 y 3 mm al restar al valor de la rodilla sana el valor de la rodilla afectada. Se encontró que 28% de los pacientes, registraron valores de KT-1000, que oscilan entre los 4 y 6 mm de desplazamiento. En 8% del total de los pacientes se encontraron valores de KT-1000 que superaron los 7 mm de desplazamiento. Se normalizan los datos obtenidos y se clasifican en 3 grados de lesión: grado 1 con lesión parcial; grado 2 con lesión completa de haz anteromedial y parcial en haz posterolateral; grado 3 con lesión completa de ambos haces. CONCLUSIONES: Se propone una clasificación para los grados de lesión del LCA con futura aplicación a una reconstrucción más personalizada.

Prevalence of dental and mandibular disorders in culled sheep in Spain.

At the slaughterhouse, 1465 culled sheep heads were studied in order to identify disorders of the mandibular cheek teeth. Of these, 227 (15.5%) had evidence of osteomyelitis. The lesional profile showed that the mandible was affected in a similar proportion on both sides (46.7% on the right side vs 50.7% on the left side), mainly in the middle region (55.3%) and with most of the lesions closed without fistulisation (89.4%). In addition, swelling was palpable, with an increase in thickness in the area of the affected body (2.65 ± 0.065 cm vs 1.74 ± 0.030 cm). In 78.6% of the animals, the regional lymph nodes were enlarged. Concerning the mandibular cheek teeth, more than half of the animals lacked at least one tooth (57.0%), with the first premolar being the most frequently missing tooth (34.8%) and the third molar the least (8.2%). The impaction of food around the teeth was very common with the posterior molars being more frequently affected. In the knowledge of the authors, this is the first study that analyses the prevalence of mandibular molar and premolar disorders in sheep, and these are revealed as an important condition affecting culled sheep.

Variation of the CD4, CD8, and MHC II cell population in granulomas of immunocompetent and immunosuppressed rabbits in Encephalitozoon cuniculi infection.

Encephalitozoon cuniculi (E. cuniculi) is a fungi-related, obligate, zoonotic, spore-forming intracellular eukaryotic microorganism. This emerging pathogen causes granulomas in brain and kidneys of infected individuals. The objective of this study was to detect the distribution of CD4, CD8 and MHCII-positive cells within granulomas in these organs in infected immunocompetent (group A) and infected immunosuppressed (group B) New Zealand white rabbits using immunohistochemistry. In brain, labeled CD4 immune cells were mainly located in the periphery of granulomas in group B. Kidneys of groups A and B, displayed CD4-positive in granulomas and were significant different when compared to brain. CD8 immune cells in brain and kidneys were disseminated in the granulomas in groups A and B; however, no significant difference was observed. MHCII-positive cells were more numerous in brain sections of group B and were significantly different when compared to kidney sections. Granulomas were not observed in control animals of group C and D. In conclusion, we identified CD4-positive cells in both the brain and kidneys of immunocompetent and immunosuppressed animals; CD8-positive cells were more numerous in brain of immunosuppressed rabbits and MHCII cells were more predominant in brain of immunocompetent rabbits. Apparently, the immunosuppression stimulated a change in the cellular phenotype of Th1- to Th2-like granulomas in brain and kidneys by an unknown mechanism. These results increase our understanding of CD4, CD8 and MHCII positive cells within the E. cuniculi granuloma microenvironment and will help in future microsporidian granulomas studies of both immunocompetent and immunosuppressed individuals.

Mercury levels in blood, urine and hair in a nation-wide sample of Spanish adults.

Mercury (Hg) is among the top 10 environmental chemicals of major public health concern (WHO). The Minamata Convention on Mercury (United Nations Environment Program, 2017), commits signing countries to control anthropogenic mercury emissions and reduce human exposure. Human biomonitoring (HBM) programs, are the most straight-forward approaches to get information on the actual exposure levels in the population and assess over time. We report here the results of a HBM study in a nationwide cross-section of Spanish adults (18-65y) as baseline values obtained before the Minamata Convention entered into force. Subsequent follow-ups will show if the Convention has been successful. The study includes 1880 blood samples, 1704 urine samples and 577 hair samples from all Spanish regions collected and analysed under a strictly quality controlled and quality assured protocol. The EU-DEMOCOPHES project demonstrated that fish and seafood are the major sources of mercury exposure and that the Spanish as well as the Portuguese populations have higher levels than other European countries. The data from the present study confirms this pattern at national level and that inhabitants in coastal regions have higher values than from inland regions. The geometric mean (GM) for blood is 6.35 µg Hg/l, in urine is 1.11 µg Hg/l and for hair is 1.91 µg Hg/g. In an international comparison these values are not exceptional. Spanish concentrations fall into the group of Easter Mediterranean populations. Although information on gender, age, occupational sector, geographical area, sampling period and frequency of fish consumption is reported in the tables, the purpose of this paper has not been to analyse the determinants of exposure in detail but to provide baseline data for future assessments and for regional authorities.

[Comparative study of anterior cruciate ligament reconstruction between the One Band and U-Two techniques]. / Estudio comparativo de reconstrucción de ligamento cruzado anterior entre las técnicas de Un Haz y U-Dos.

INTRODUCTION: ACL injuries are found within the most common ligament injuries. This has led to the development of different surgical techniques to restore knee stability. MATERIAL Y METHODS: Clinical study, randomized, blind comparing ACL reconstruction techniques with One Band and «U-Two¼ using clinical scales and arthrometria with KT-1000 and Pivot Shift Meter. RESULTS: Of 36 patients, 52.94% was drawn for the One Band technique and 47.06% for «U-Two¼. 11.76% of patients had a displacement greater than 11mm in the affected knee with KT-1000. 8.82% showed an equal anterior displacement on both knees. One patient had a major previous displacement after reconstruction surgery with the one band technique, but with improvement on clinical scales. Pivot Shift measurements found a difference in displacement greater than 4,000 m/s on the X axis following the One Band technique compared to the healthy knee calculating integrals, while with U-Two the difference was less than 600 m/s. On the Y axis a difference of 3,500 m/s was found between the healthy and the injured leg, which decreases to less than 2,000 m/s after reconstruction using U-Two technique. CONCLUSIONS: Differences have been found throughout the study in patient evolution, indicating that repair using the U-Dos technique has better results in recovering the anteroposterior and rotational stability of the affected limb.

INTRODUCCIÓN: Las lesiones del LCA se encuentran dentro de las lesiones ligamentarias más frecuentes. Esto ha llevado al desarrollo de diferentes técnicas quirúrgicas para recuperar la estabilidad de la rodilla. MATERIAL Y MÉTODOS: Estudio clínico, aleatorizado, ciego comparando técnicas de reconstrucción de LCA con Un Haz y «U-Dos¼ mediante escalas clínicas y artrometría con KT-1000 y Pivot Shift Meter. RESULTADOS: De 36 pacientes, 52.94% fue sorteado para la técnica de Un Haz y 47.06% para «U-Dos¼. En 11.76% de los pacientes se presentó un desplazamiento mayor a 11 mm en la rodilla afectada con KT-1000. En 8.82% se mostró un desplazamiento anterior igual en ambas rodillas. Un paciente presentó un desplazamiento anterior mayor posterior a la cirugía de reconstrucción con la técnica de Un Haz, pero con mejoría en las escalas clínicas. En las mediciones de Pivot Shift se encontró una diferencia en el desplazamiento mayor a los 4,000 m/s en el eje de las X tras la técnica de Un Haz en comparación con la rodilla sana calculando integrales, mientras que con U-Dos la diferencia fue menor de 600 m/s. En el eje de «Y¼ se encontró una diferencia 3,500 m/s entre la pierna sana y la lesionada, la cual disminuye a menos de 2,000 m/s tras la reconstrucción mediante técnica de U-Dos. CONCLUSIONES: A lo largo del estudio se han encontrado diferencias en la evolución de los pacientes que indican que la reparación mediante la técnica de U-Dos tiene mejores resultados al lograr recuperar la estabilidad anteroposterior y rotacional del miembro afectado.

An Alternative Treatment Against Acanthocephala ( Prosthenorchis elegans) in Captive Squirrel Monkeys ( Saimiri sciureus) in Mexico.

We provide the first report of Acanthocephala ( Prosthenorchis elegans) in Mexican non-human primates. There has been no known treatment against this parasite except for surgical removal, and this has been relatively ineffective because of the small juveniles. We report the presence of P. elegans in a captive breeding colony of squirrel monkeys ( Saimiri sciureus) in Mexico, and we describe a successful treatment protocol. Treatment involved 2 steps: oral administration of the drugs loperamide chlorhydrate (0.5 mg/0.9 kg/3 days) and niclosamide (0.2 mg/0.9 kg/3 days) followed by surgical removal of adult worms from the intestine. Fecal examination during treatment revealed live adults but no living juveniles and no eggs. Surgery after 1 wk of treatment revealed the presence of adults and an absence of juvenile parasites. All adults were physically extracted during the surgery. All subjects recovered from surgery within 1 wk.

Technical Note: A new device for cervical insemination of sheep - design and field test.

Deep semen deposition, avoiding retrograde flow, lesions and stress, has proved to be very important in the success of sheep AI. The objective of the present study was to develop a new, suitable anti-retrograde flow device for sheep cervical AI (DARIO) that enables deep deposition of semen into the cervix without any modifications to the procedures currently used, and to compare the fertility, fecundity, and prolificacy rates between DARIO and a traditional catheter. Field tests were performed on 16 farms actively participating in the non-profit National Association of Rasa Aragonesa Breeders´ genetic selection scheme and where sheep management was similar. A total of 242 AI lots were considered, including 1,299 ewes; 126 lots (662 ewes) were inseminated using DARIO, and 116 lots (637 ewes) using a traditional commercially-available catheter (control group). Several factors affecting AI results were included in the model for mean comparison between DARIO and control groups (farm and ram as random factors; catheter, year and photoperiod as fixed effects; catheter × photoperiod interaction). The type of catheter had a significant effect on fertility ( < 0.01) and fecundity rates ( < 0.01) but no significant effect was detected on the prolificacy rate ( = 0.45). For fertility rate (percentage of ewes lambing after AI), means ± SE for DARIO and control groups were 59.44 ± 2.13% and 49.60 ± 2.48%, respectively; for fecundity rates, means ± SE for DARIO and control groups were 0.99 ± 0.04 and 0.82 ± 0.05 lambs/inseminated ewe, respectively, and, for prolificacy rates, means ± SE for DARIO and control groups were 1.68 ± 0.04 and 1.63 ± 0.04 lambs/ewe lambing, respectively. Fertility rate was greater in the decreasing photoperiod ( = 0.01). Significant effects were found for both year ( < 0.05) and farm ( < 0.01) on fertility, fecundity, and prolificacy rates. Neither ram nor catheter × photoperiod showed any significant effects on the variables investigated ( > 0.05). Overall, the use of DARIO instead of the traditional commercially-available catheter increased both fertility and fecundity rates; the marginal mean differences were 9.05 pregnant ewes per 100 inseminated and 0.15 lambs per inseminated ewe, respectively.

Jaagsiekte Sheep Retrovirus Can Reach Peyer's Patches and Mesenteric Lymph Nodes of Lambs Nursed by Infected Mothers.

Ovine pulmonary adenocarcinoma (OPA) is a contagious lung cancer of sheep caused by jaagsiekte sheep retrovirus (JSRV). It is generally accepted that transmission by the respiratory route occurs under natural conditions. However recent studies strongly indicate that JSRV can also be transmitted to lambs perinatally via colostrum and milk (C/M). The aim of this work was to confirm that C/M can transmit JSRV infection to lambs under natural conditions and investigate the initial events associated with this transmission route. We have analyzed the presence of JSRV in C/M samples from 22 naturally infected, asymptomatic ewes throughout a lactation period, and in various tissues collected from a group of 36 of their lambs that were fed naturally. The lambs were euthanized at 12, 24, 48, and 72 hours and at 5 and 10 days after birth. We detected JSRV-provirus by PCR in the somatic C/M cells from 10/22 ewes (45.45%). The virus was also detected in 9/36 lambs (25%). JSRV-infected cells, with lymphoreticular-like morphology, were observed by immunohistochemistry (IHC) and in situ hybridization (ISH) in Peyer's patches (PP) from the small intestine of the youngest lambs and in mesenteric lymph nodes (MLN) from lambs older than 72 hours. The virus was also detected by PCR in white blood cells (WBC) in 2/36 lambs (5.5%). These results confirm colostral transmission of JSRV to lambs under natural conditions. Infected lymphoreticular cells contained in C/M appear to be involved. These cells can cross the intestinal barrier of newborn lambs, reach the MLN and enter into circulation.

Vaccination schedules in small ruminant farms.

Development and implementation of health management plans is the cornerstone of profitable farms; prevention of microbial diseases by means of vaccination is an integral part of such a plan. In every production type and management system in small ruminants, microbial diseases have a major significance, hence their proper control must be based in good health management practices, including use of effective and safe vaccines. Development of various types of vaccines is evolving very quickly in recent years and the improvement of new type of vaccines offers prospects. The article reviews and discusses vaccination programs and latest advances in development of vaccines against diseases that cause major economic losses in small ruminants. Specifically, vaccination schedules for the following diseases are reviewed: bacterial abortion (abortion associated with Brucella melitensis, Campylobacter spp., Chlamydophila abortus, Coxiella burnetii, Salmonella abortus ovis or Salmonella brandenburg), caseous lymphadenitis, clostridial diseases, colibacillosis, contagious echtyma, epididymitis caused by Brucella ovis, footrot, mammary diseases (contagious agalactia, mastitis), paratuberculosis and respiratory diseases (respiratory disease caused by Mannheimia haemolytica or other Pasteurellaceae).

Flow and clogging of a sheep herd passing through a bottleneck.

We present an experimental study of a flock passing through a narrow door. Video monitoring of daily routines in a farm has enabled us to collect a sizable amount of data. By measuring the time lapse between the passage of consecutive animals, some features of the flow regime can be assessed. A quantitative definition of clogging is demonstrated based on the passage time statistics. These display broad tails, which can be fitted by power laws with a relatively large exponent. On the other hand, the distribution of burst sizes robustly evidences exponential behavior. Finally, borrowing concepts from granular physics and statistical mechanics, we evaluate the effect of increasing the door size and the performance of an obstacle placed in front of it. The success of these techniques opens new possibilities regarding their eventual extension to the management of human crowds.

Variability of the egg hatch assay to survey benzimidazole resistance in nematodes of small ruminants under field conditions.

The egg hatch assay (EHA) is one of the main in vitro methods for detection of benzimidazole resistance in nematode parasites of small ruminants. However, although the EHA has been standardised at the laboratory level, the diagnostic performance of this method has not been fully characterised for field screenings. In the present work, monthly variation of benzimidazole resistance estimated by EHA was surveyed over two years in three sheep flocks and in one goat and an additional sheep flock sharing the same pastures. Resistance was measured by calculating both the effective dose of thiabendazole (TBZ) that inhibited hatching of ≥50% of parasite eggs (ED50) and the proportion (Pdd) of eggs hatching at a discriminating dose of 0.1 µg/ml TBZ. Pdd exhibited higher variability than ED50, in agreement with the higher sensitivity of Pdd to changes in resistance levels. Both resistance parameters, however, were highly correlated, and their variation was similarly related to the same factors. Resistance levels differed among sheep flocks, and the resistance level of the goat flock was higher than that measured for the sheep flock sharing the same pasture. Moreover, monthly variation of resistance in goats did not mirror that recorded in sheep. Resistance levels varied seasonally, with the highest values recorded in the spring, and they were inversely related to the number of days that samples were stored under anaerobic conditions. In addition, they were directly associated with the relative abundance of Teladorsagia spp. but inversely related to the relative abundance of Haemonchus spp. After controlling for the effects of these identified factors for variation, inter-monthly sampling variation due to unknown factors was the main source of variability, accounting for more than 60-70% of variance for both resistance parameters and yielding absolute estimation errors higher than 0.06 for ED50 or 0.2 for Pdd when resistance was estimated from a single sampling. Optimum sample size, estimated from variance components, suggested that at least 4-5 samplings would be needed to halve this absolute error, whereas additional samplings would slightly increase precision but at the cost of substantially increasing sampling effort. More research is needed to identify the main factors involved in this inter-sampling variation to standardise the implementation of EHA under field conditions.

Miniaturized selective pressurized liquid extraction of polychlorinated biphenyls and polybrominated diphenyl ethers from feedstuffs.

A new miniaturized pressurized liquid extraction (PLE) with in-cell purification method has been developed for the simultaneous extraction of endogenous prioritary and toxic polychlorinated biphenyls (PCBs) and environmentally relevant tri- to deca-brominated diphenyl ether (PBDE) congeners from different feed matrices. Parameters affecting the efficiency of the selective PLE process, such as sorbent:matrix ratio, volume and nature of the extraction solvent, PLE working mode, extraction time and temperature, and amount of co-sorbents, were optimized. n-Hexane and n-hexane:dichloromethane (1:1, v/v) were used as extraction solvents. 8-mL of organic solvents and 3.5 g of sorbents sufficed for complete sample treatment. Only 0.25 g of feed sample were required for accurate determination of the endogenous PCBs studied using gas chromatography with a micro-electron capture detector (GC-µECD) during method development, and for PBDE analysis using either GC-µECD or gas chromatography with negative chemical ionization-quadrupole mass spectrometry (GC-NCI-qMS). Gas chromatography coupled to ion trap detection working in tandem mode, GC-ITD (MS/MS), was used for final PCB confirmation. Additional purification of the sample extracts was not required. The performance of the complete PLE-based method was evaluated at two spiking levels, 0.4 and 4 ng/g wet weight. Recoveries in the range 60-120% were obtained for PCBs, while those of PBDEs ranged from 86% to 114% for most of the target analytes. The relative standard deviations were in general lower than 20%. The optimized procedure was applied to the determination of the investigated PCBs and PBDEs in a variety of feed samples.

Chronic proliferative rhinitis associated with Salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) in sheep in Spain.

A chronic proliferative rhinitis in sheep associated with Salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) is described. Ten adult sheep from eight traditionally managed Rasa Aragonesa flocks located in Aragon (Spain) were studied. Clinical signs began with bilateral thick mucus nasal discharge, wheezing and snoring and progressed to partial or complete obstruction of the nostrils. Necropsy examination revealed swollen ventral nasal turbinates with a roughened mucosal surface partially covered by small polyps. Histopathology revealed chronic proliferative rhinitis with a predominant population of neutrophils that infiltrated the mucosal epithelium. Plasma cells and macrophages were present in the lamina propria. Organisms expressing Salmonella antigen immunohistochemically were detected within epithelial cells. Salmonella enterica subspecies diarizonae serovar 61:k:1, 5, (7) was isolated as a sole microorganism from nasal swabs taken from five animals. The implication of finding this bacterium in various diseases in sheep and its role as a potential zoonosis are discussed.

Management and environmental factors related to benzimidazole resistance in sheep nematodes in Northeast Spain.

A survey to determine the level of parasite resistance to benzimidazoles (BZ) under field conditions was performed on 107 commercial sheep farms located in the Aragon region of northeast Spain. Resistance was measured using the discriminant dose, a simplified form of the in vitro egg hatch assay (EHA). Taking into account the spatial structure of the data, a multivariate approach was applied to management and environmental variables as well as to their relationships with BZ resistance levels compiled from each flock. Results estimated that 11% of flocks had resistant parasite populations, although we suspected the presence of BZ-resistant parasite strains in 98% of the sample. Resistance levels were more similar among the nearest flocks, suggesting a contagious spatial distribution of resistance (i.e., resistance at neighbouring farms was not independent from one another). Management variables such as frequency of deworming, grazing in private pastures and underdosing were positively related to resistance levels, whereas only the use of BZ was negatively related to resistance levels, likely because BZ were replaced by other anthelmintics in flocks where reduced BZ efficacy was suspected. In addition to climatic conditions and seasonality, land use was an environmental variable associated with observed BZ resistance levels. Generally, resistance was highest in cooler and wetter areas but was lower in flocks sampled during January-March compared to flocks sampled in April-June or October-December. Variation partitioning procedures showed that the variation of resistance explained by the effect of environmental variables was higher than management variables. The effects of both variable groups, however, highly overlapped with the spatial structure of resistant levels, which suggests that a considerable amount of the effects attributable to both variable groups may be actually due to the spatial distribution of resistance. The resistance variation explained by the spatial component suggested that other uncontrolled factors acting at short spatial scale (e.g., common management and environmental variables; the importation of resistant strains and their posterior spread across neighbouring flocks; the selection history of the worms carried out by historical management events previous to this survey; and genetic, physiological or both types of parasite population variation) could yield this contagious spatial structure of BZ resistance. Although further research is needed, both seasonal variation and the dependence of resistance levels among neighbouring flocks should be taken into account in the design of future research or observational resistance programmes to minimise spatial and temporal pseudo-replication. Thus, research would avoid biased estimations of resistance prevalence or of its relationship with putative factors.

Ovine heritable arthrogryposis multiplex congenita with probable lethal autosomal recessive mutation.

A novel congenital syndrome in lambs is described that is characterized by: (1) kyphoscoliosis (severe curvature, hunching and twisting of the thoracic spine, with associated abnormalities of the ribs and sternum), (2) distal arthrogryposis of the carpal and tarsal joints, and (3) cleft hard and soft palate or palatoschisis (a median fissure of the palate). Male and female lambs are affected equally and in multiple births there may be only one affected lamb. The affected lambs are born full term, but die shortly after birth because they are unable to start breathing. Affected lambs have slightly reduced bodyweight (due to low muscle mass) compared with normal newborn lambs of the same flock. The syndrome is remarkably similar to the recently described bovine heritable arthrogryposis multiplex congenita in the Angus breed. Genetic analysis of the flock by means of DNA microsatellite markers, together with study of the reproductive management of the flock, allowed us to discount an environmental aetiology (e.g. intoxications or infections). In contrast, evidence supports an autosomal recessive inherited disease for which the name ovine heritable arthrogryposis multiplex congenita is proposed.