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The Schistosoma mansoni cercarial elastase (SmCE) has previously been shown to be poorly immunogenic in mice. However, a minority of mice were able to produce antibodies against SmCE after multiple immunizations with crude preparations containing the enzyme. These mice were partially protected against challenge infections of S. mansoni. In the present study, we show that in contrast to the poor immunogenicity of the enzymatically active native form of SmCE derived from a crude preparation (cercarial transformation fluid), immunization of CBA/Ca mice with two enzymatically inactive forms, namely purified native SmCE or a recombinant SmCE fused to recombinant Schistosoma japonicum glutathione S-transferase (rSmCE-SjGST), after adsorption onto aluminum hydroxide adjuvant, induced specific anti-SmCE immunoglobulin G (IgG) in all mice within 2 weeks of the second immunization. The IgG antibody response to rSmCE-SjGST was mainly of the IgG1 subclass. These results suggest that inactive forms of the antigen could be used to obtain the optimum immunogenic effects as a vaccine candidate against schistosomiasis. Mice immunized with the rSmCE-SjGST on alum had smaller mean worm burdens and lower tissue egg counts when compared with adjuvant alone- and recombinant SjGST-injected controls. The native SmCE was antigenically cross-reactive with homologous enzymes of Schistosoma haematobium and Schistosoma margrebowiei.
Eating less frequently is associated with increased obesity risk in older children but data are potentially confounded by reverse causation, where bigger children eat less often in an effort to control their weight. Longitudinal data, particularly in younger children, are scarce. We aimed to determine whether eating frequency (meals and snacks) at 2 years of age is associated with past, current or subsequent BMI.
Cohort analysis of a randomised controlled trial. Eating frequency at 2 years of age was estimated using 48 h diaries that recorded when each child ate meals and snacks (parent-defined) in five-minute blocks. Body length/height and weight were measured at 1, 2 and 3·5 years of age. Linear regression assessed associations between the number of eating occasions and BMI Z-score, before and after adjustment for potential confounding variables.
Prevention of Overweight in Infancy (POI) study, Dunedin, New Zealand.
Children (n 371) aged 1–3·5 years.
On average, children ate 5·5 (sd 1·2) times/d at 2 years of age, with most children (88–89 %) eating 4–7 times/d. Eating frequency at 2 years was not associated with current (difference in BMI Z-score per additional eating occasion; 95 % CI: −0·02; −0·10, 0·05) or subsequent change (0·02; −0·03, 0·06) in BMI. Similarly, BMI at age 1 year did not predict eating frequency at 2 years of age (difference in eating frequency per additional BMI Z-score unit; 95 % CI: −0·03; −0·19, 0·13).
Number of eating occasions per day was not associated with BMI in young children in the present study.
Healthy calves are fundamental to any profitable dairy enterprise. Research to-date, has focused on year-round calving systems which experience many different challenges compared to spring-calving systems. The objective of the present study was to determine the on-farm dry cow, calving, and colostrum management practices of spring-calving dairy production systems, and quantify their associations with herd size and herd expansion status (i.e. expanding or not expanding). Information on these management practices was available from a survey of 262 Irish spring-calving dairy farmers, representative of the Irish national population. Herd expansion in the 2 years before, and the year that the survey was conducted was not associated with any of the management practices investigated. Fifty-three percent of respondents had an average calving season length of 10 to14 weeks with 35% of herds having a longer calving season. Previous research in cattle has documented that both colostrum source and feeding management are associated with the transmission of infectious disease from cow to calf. In the present study 60% of respondents fed calves colostrum from their own dam; however, 66% of those respondents allowed the calf to suckle the dam, 23% of survey respondents fed calves pooled colostrum. Larger herds were more likely (P<0.01) to use pooled colostrum supplies, while smaller herds were more likely (P<0.05) to allow the calf to suckle the dam. The majority (86%) of respondents had stored supplies of colostrum; average-sized herds had the greatest likelihood of storing colostrum (P<0.05), compared to other herd sizes; larger sized herds had a lesser likelihood (P<0.05) of storing colostrum in a freezer, compared to other herd sizes. Although freezing colostrum was the most common method used to store colostrum (54% of respondents), 17% of respondents stored colostrum at room temperature, 29% of which stored it at room temperature for greater than 4 days. The results from the present study indicate that a particular focus needs to be placed on calving and colostrum management because this study has highlighted a number of areas which are below international standards, and may have repercussions for calf health. Furthermore, management practices on larger farms could be improved and, as these represent the future of dairy farming, a focus needs to be placed on them. Expanding herds are not a particular concern as herd expansion, independent of herd size, does not seem to be associated with calving and colostrum management practices on Irish spring-calving dairy herds.
The 2012 West Nile virus (WNV) epidemic was the largest since 2003 and the North Texas region was the most heavily impacted. We conducted a serosurvey of blood donors from four counties in the Dallas–Fort Worth area to characterize the epidemic. Blood donor specimens collected in November 2012 were tested for WNV-specific antibodies. Donors positive for WNV-specific IgG, IgM, and neutralizing antibodies were considered to have been infected in 2012. This number was adjusted using a multi-step process that accounted for timing of IgM seroreversion determined from previous longitudinal studies of WNV-infected donors. Of 4971 donations screened, 139 (2·8%) were confirmed WNV IgG positive, and 69 (1·4%) had IgM indicating infection in 2012. After adjusting for timing of sampling and potential seroreversion, we estimated that 1·8% [95% confidence interval (CI) 1·5–2·2] of the adult population in the Dallas–Fort Worth area were infected during 2012. The resulting overall estimate for the ratio of infections to reported WNV neuroinvasive disease (WNND) cases was 238:1 (95% CI 192–290), with significantly increased risk of WNND in older age groups. These findings were very similar to previous estimates of infections per WNND case, indicating no change in virulence as WNV evolved into an endemic infection in the United States.
A survey of management practices in 309 Irish dairy herds was used to identify risk factors for the presence of antibodies to Salmonella, Neospora caninum and Leptospira interrogans serovar hardjo in extensively managed unvaccinated dairy herds. A previous study documented a herd-level seroprevalence in bulk milk of 49%, 19% and 86% for Salmonella, Neospora caninum and leptospira interrogans serovar hardjo, respectively in the unvaccinated proportion of these 309 herds in 2009. Association analyses in the present study were carried out using multiple logistic regression models. Herds where cattle were purchased or introduced had a greater likelihood of being positive to leptospira interrogans serovar hardjo (P<0.01) and Salmonella (P<0.01). Larger herds had a greater likelihood of recording a positive bulk milk antibody result to leptospira interrogans serovar hardjo (P<0.05). Herds that practiced year round calving were more likely to be positive to Neospora caninum (P<0.05) compared to herds with a spring-calving season, with no difference in risk between herds that practiced split calving compared to herds that practiced spring calving. No association was found between presence of dogs on farms and prevalence of Neospora caninum possibly due to limited access of dogs to infected materials including afterbirths. The information from this study will assist in the design of suitable control programmes for the diseases under investigation in pasture-based livestock systems.
Transfer of sufficient immunoglobulin G (IgG) to the neonatal calf via colostrum is vital to provide the calf with immunological protection and resistance against disease. The objective of the present study was to determine the factors associated with both colostral IgG concentration and colostral weight in Irish dairy cows. Fresh colostrum samples were collected from 704 dairy cows of varying breed and parity from four Irish research farms between January and December 2011; colostral weight was recorded and the IgG concentration was determined using an ELISA method. The mean IgG concentration in the colostrum was 112 g/l (s.d. = 51 g/l) and ranged from 13 to 256 g/l. In total, 96% of the samples in this study contained >50 g/l IgG, which is considered to be indicative of high-quality colostrum. Mean colostral weight was 6.7 kg (s.d. = 3.6 kg) with a range of 0.1 to 24 kg. Factors associated with both colostral IgG concentration and colostral weight were determined using a fixed effects multiple regression model. Parity, time interval from calving to next milking, month of calving, colostral weight and herd were all independently associated with IgG concentration. IgG concentration decreased (P < 0.01) by 1.7 (s.e. = 0.6) g/l per kg increase in the colostral weight. Older parity cows, cows that had a shorter time interval from calving to milking, and cows that calved earlier in spring or in the autumn produced colostrum with higher IgG concentration. Parity (P < 0.001), time interval from calving to milking (P < 0.01), weight of the calf at birth (P < 0.05), colostral IgG concentration (P < 0.01) and herd were all independently associated with colostral weight at the first milking. Younger parity cows, cows milked earlier post-calving, and cows with lighter calves produced less colostrum. In general, colostrum quality of cows in this study was higher than in many previous studies; possible reasons include use of a relatively low-yielding cow type that produces low weight of colostrum, short calving to colostrum collection interval and grass-based nutritional management. The results of this study indicate that colostral IgG concentration can be maximised by reducing the time interval between calving and collection of colostrum.
Observations that older people who enjoy life more tend to live longer suggest that psychological well-being may be a potential resource for healthier ageing. We investigated whether psychological well-being was associated with incidence of physical frailty.
We used multinomial logistic regression to examine the prospective relationship between psychological well-being, assessed using the CASP-19, a questionnaire that assesses perceptions of control, autonomy, self-realization and pleasure, and incidence of physical frailty or pre-frailty, defined according to the Fried criteria (unintentional weight loss, weakness, self-reported exhaustion, slow walking speed and low physical activity), in 2557 men and women aged 60 to ⩾90 years from the English Longitudinal Study of Ageing (ELSA).
Men and women with higher levels of psychological well-being were less likely to become frail over the 4-year follow-up period. For a standard deviation higher score in psychological well-being at baseline, the relative risk ratio (RR) for incident frailty, adjusted for age, sex and baseline frailty status, was 0.46 [95% confidence interval (CI) 0.40–0.54]. There was a significant association between psychological well-being and risk of pre-frailty (RR 0.69, 95% CI 0.63–0.77). Examination of scores for hedonic (pleasure) and eudaimonic (control, autonomy and self-realization) well-being showed that higher scores on both were associated with decreased risk. Associations were partially attenuated by further adjustment for other potential confounding factors but persisted. Incidence of pre-frailty or frailty was associated with a decline in well-being, suggesting that the relationship is bidirectional.
Maintaining a stronger sense of psychological well-being in later life may protect against the development of physical frailty. Future research needs to establish the mechanisms underlying these findings.
During 2007–2009 a UK-wide, 3-year stratified randomized survey of UK chicken broiler flocks was conducted to estimate the prevalence of Campylobacter-infected batches of birds at slaughter. Thirty-seven abattoirs, processing 88·3% of the total UK slaughter throughput, were recruited at the beginning of the survey. Of the 1174 slaughter batches sampled, 79·2% were found to be colonized with Campylobacter, the majority of isolates being C. jejuni. Previous partial depopulation of the flock [odds ratio (OR) 5·21], slaughter in the summer months (categorized as June, July and August; OR 14·27) or autumn months (categorized as September, October and November; OR 1·70) increasing bird age (40–41 days, OR 3·18; 42–45 days, OR 3·56; ⩾46 days, OR 13·43) and higher recent mortality level in the flock (1·00–1·49% mortality, OR 1·57; ⩾1·49% mortality, OR 2·74) were all identified as significant risk factors for Campylobacter colonization of the birds at slaughter. Time in transit to the slaughterhouse of more than 2·5 h was identified as a protective factor (OR 0·52).
Consistent positive relationships have been found between birth weight and grip strength in adults but evidence in children is limited. In a prospective general population birth cohort (Southampton Women's Survey), grip strength and anthropometry (height and weight) were measured in 968 children at the age of 4 years. Mean (standard deviation (s.d.)) birth weight was 3.48 (0.52) kg. Birth weight, adjusted for sex and gestational age, was positively associated with grip strength (β = 0.22 kg/s.d. increase in adjusted birth weight; 95% CI 0.11, 0.34). The relationship was attenuated after adjustment for current height and weight such that it became non-significant (β = 0.03 kg/s.d. increase in adjusted birth weight; 95% CI−0.08, 0.14), suggesting that body size may be on the causal pathway. Early influences on muscle development appear to impact on grip strength in children, as well as adults.
Symptoms of anxiety and depression are common in older people, but the relative importance of factors operating in early and later life in influencing risk is unclear, particularly in the case of anxiety.
We used data from five cohorts in the Healthy Ageing across the Life Course (HALCyon) collaborative research programme: the Aberdeen Birth Cohort 1936, the Caerphilly Prospective Study, the Hertfordshire Ageing Study, the Hertfordshire Cohort Study and the Lothian Birth Cohort 1921. We used logistic regression to examine the relationship between factors from early and later life and risk of anxiety or depression, defined as scores of 8 or more on the subscales of the Hospital Anxiety and Depression Scale, and meta-analysis to obtain an overall estimate of the effect of each.
Greater neuroticism, poorer cognitive or physical function, greater disability and taking more medications were associated in cross-sectional analyses with an increased overall likelihood of anxiety or depression. Associations between lower social class, either in childhood or currently, history of heart disease, stroke or diabetes and increased risk of anxiety or depression were attenuated and no longer statistically significant after adjustment for potential confounding or mediating variables. There was no association between birth weight and anxiety or depression in later life.
Anxiety and depression in later life are both strongly linked to personality, cognitive and physical function, disability and state of health, measured concurrently. Possible mechanisms that might underlie these associations are discussed.
Q fever (Coxiella burnetii) is a zoonotic disease of increasing public health importance. The objective of this study was to estimate the prevalence of, and risk factors associated with, exposure to C. burnetii in cattle in the Republic of Ireland. Bulk-tank milk samples from 290 dairy herds and 1659 sera from 332 dairy and beef herds, randomly sampled, were tested by indirect ELISA to detect antibodies to C. burnetii. In total, 37·9% of bulk-milk sample herds and 1·8% of sera (from 6·9% of herds) were antibody positive. Of risk factors tested using logistic regression analysis, only large herd size (bulk-milk analysis) and dairy breed (serum analysis) significantly increased the odds of being positive for antibodies to C. burnetii. Herds with positive milk or serum samples were randomly distributed throughout the Republic of Ireland and no clustering was observed. The use of an ELISA to test bulk-milk samples collected by randomized stratified sampling is a cost-effective method by which national herd prevalence can be estimated by active surveillance.
Foetal development may permanently affect muscle function. Indian newborns have a low mean birthweight, predominantly due to low lean tissue and muscle mass. We aimed to examine the relationship of birthweight, and arm muscle area (AMA) at birth and post-natal growth to handgrip strength in Indian children. Grip strength was measured in 574 children aged 9 years, who had detailed anthropometry at birth and every 6–12 months post-natally. Mean (standard deviation (s.d.)) birthweight was 2863 (446) g. At 9 years, the children were short (mean height s.d. −0.6) and light (mean weight s.d. −1.1) compared with the World Health Organization growth reference. Mean (s.d.) grip strength was 12.7 (2.2) kg (boys) and 11.0 (2.0) kg (girls). Weight, length and AMA at birth, but not skinfold measurements at birth, were positively related to 9-year grip strength (β = 0.40 kg/s.d. increase in birthweight, P < 0.001; and β = 0.41 kg/s.d. increase in AMA, P < 0.001). Grip strength was positively related to 9-year height, body mass index and AMA and to gains in these measurements from birth to 2 years, 2–5 years and 5–9 years (P < 0.001 for all). The associations between birth size and grip strength were attenuated but remained statistically significant for AMA after adjusting for 9-year size. We conclude that larger overall size and muscle mass at birth are associated with greater muscle strength in childhood, and that this is mediated mainly through greater post-natal size. Poorer muscle development in utero is associated with reduced childhood muscle strength.
Background: The Hospital Anxiety and Depression Scale (HADS) is widely used but evaluation of its psychometric properties has produced equivocal results. Little is known about its structure in non-clinical samples of older people.
Methods: We used data from four cohorts in the HALCyon collaborative research program into healthy aging: the Caerphilly Prospective Study, the Hertfordshire Ageing Study, the Hertfordshire Cohort Study, and the Lothian Birth Cohort 1921. We used exploratory factor analysis and confirmatory factor analysis with multi-group comparisons to establish the structure of the HADS and test for factorial invariance between samples.
Results: Exploratory factor analysis showed a bi-dimensional structure (anxiety and depression) of the scale in men and women in each cohort. We tested a hypothesized three-factor model but high correlations between two of the factors made a two-factor model more psychologically plausible. Multi-group confirmatory factor analysis revealed that the sizes of the respective item loadings on the two factors were effectively identical in men and women from the same cohort. There was more variation between cohorts, particularly those from different parts of the U.K. and in whom the HADS was administered differently. Differences in social-class distribution accounted for part of this variation.
Conclusions: Scoring the HADS as two subscales of anxiety and depression is appropriate in non-clinical populations of older men and women. However, there were differences between cohorts in the way that individual items were linked with the constructs of anxiety and depression, perhaps due to differences in sociocultural factors and/or in the administration of the scale.
Following the disclosure of Mycobacterium bovis infection in badgers in East Sussex in 1976, badgers have been examined from and around farms on which cattle have become infected, but with no other attributable source of infection. These farms are confined to the downland of the south-west of the county and M. bovis has been confirmed in badger populations utilising their land. The available evidence indicates that M. bovis infection in badgers is also confined to this area. A detailed study in one area on the South Downs suggested that M. bovis is endemic in the badger population and therefore presents a continued risk for cattle occupying the area.
A detailed investigation of the possible role of wild mammals, other than badgers, in the maintenance of Mycobacterium bovis in an area on the South Downs of East Sussex was carried out over 3 years. Estimates of population sizes were made where possible and minimum sample sizes were selected to be 95 % certain of including at least one infected animal if the prevalence was at least 5 %. Samples of wild mammals were taken from populations which had the highest potential direct or indirect contact rate with known infected badgers. M. bovis was not isolated from any of the 15 species of wild mammals.
It was concluded that badgers are able to maintain M. bovis in an area independently of other species, and that in the area studied other species were not a source of infection for the cattle herds.
Following epidemiological and ecological studies of a defined badger population in an area of East Sussex, removal of all badgers by cage trapping was attempted. Trapping was incomplete due to the activities of protesters. Forty-seven badgers were caught from the eight social groups. All badgers were examined clinically and samples of faeces, urine and tracheal aspirate were taken, together with swabs from any bite wounds, for bacteriological examinations. Forty-five animals were skin tested using whole killed cells of Mycobacterium bovis strain AN5, bovine PPD Weybridge and new human tuberculin. Skin test results were recorded after 24 and 72 h. All badgers were killed and subjected to a post-mortem and bacteriological examination.
M. bovis was detected in 10 (21·3%) badgers at post-mortem and in 2 badgers from clinical samples. Four social groups were infected. Positive skin test results were recorded at 72 h with bovine PPD (2 μg and 20 μg/ml), strain AN 5 (1 mg/ml) and human tuberculin (2 μg/ml), but not with human tuberculin at 20 μg/ml. Histological sections of the skin test reactions showed the cellular types typical of delayed-type hypersensitivity. The skin test reactions observed were neither sensitive nor specific enough to be of practical value.
The history and epidemiology of bovine tuberculosis in cattle herds in East Sussex are described. Since 1960, following the compulsory eradication scheme for tuberculosis, the incidence of herd infection has been low. The epidemiological features of herd infection have been sporadic incidents, with only small numbers of cattle becoming infected in the majority of incidents. There was no evidence of endemic Mycobacterium bovis infection in the cattle population in East Sussex in recent years, but a low risk of infection for cattle on the South Downs, from badgers, was apparent.
Pasture-based Holstein–Friesian cows from three genetic groups differing in the Irish ‘Economic Breeding Index’ (EBI) value and genetic background, namely North-American (NA) national average EBI genetic merit (LOW-NA, n = 42), North-American high EBI genetic merit (HIGH-NA, n = 42) and New Zealand (NZ) high EBI genetic merit (HIGH-NZ, n = 42), were studied. These genetic groups have been selected in different environments: pasture for NZ and confinement for NA. The objective was to determine the effect of genetic group on haematological and acute phase proteins profiles (white blood cell (WBC) counts, red blood cell (RBC) counts, acute phase proteins: serum amyloid A (SAA) and haptoglobin), health (rectal temperature (RT), clinical mastitis (CM) and somatic cell score), calving performance (stillbirth, calving assistance) and post-partum reproductive parameters (endometritis and ovarian cyclicity). Blood sampling and data recording took place 3 weeks pre-calving up to 7 weeks post-calving. Linear mixed models, logistic regression and generalised estimating equations were used for data analysis. HIGH-NZ animals had the highest (P < 0.05) RBC mean corpuscular volume (50.0 fl), exhibited a different WBC distribution pattern (P < 0.05) and had the lowest (P < 0.05) mean RT (38.4°C) for the first 10 days post-calving. These findings suggest enhanced reticulocyte turnover, peripartum response mechanisms and thermoregulation in the HIGH-NZ compared to the other two genetic groups. LOW-NA animals had the highest SAA peak throughout the peripartum period (55.12 mg/l, P < 0.05) and a tendency for higher somatic cell scores (P < 0.10) in early lactation. The HIGH-NA animals had the lowest incidence of udder quarter milk sample bacteria at calving, suggesting better udder health when commencing lactation. No differences were detected between genetic groups in calving performance, post-partum reproductive parameters or CM in the first 42 days post-calving. These results suggest that while inherited peripartum adaptation strategies have been developed by the different genetic groups selected in different environments (pasture = NZ v. confinement = NA), such differences have minimal impact on peripartum clinical health.
The lethal t-haplotypes of the mouse fall into several distinct complementation groups, and varying degrees of partial complementation occur when haplotypes from different groups are crossed. The haplotype th20 arose as a mutant from the haplotype t6, and is thought to include a small deletion covering loci near the t-lethals. In this paper the complementarity of th20 was compared with that of its parent haplotype t6. th20 showed weaker complementation than t6 of the haplotypes tw5, tw32 and tw1. Hence the loci of these lethals were probably exposed by the deletion in th20. However, th20 showed full complementation of tw18 and showed full viability in compound with the dominant brachyury allele hairpin-tail, Thp. Therefore, the th20 deletion probably does not overlap the presumed deletion in Thp, nor extend to the locus of the tw18 lethal. The significance of the weak complementation of tw5, tw32 and tw1 is discussed.