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Acute and chronic tonsillitis are frequently treated with antibiotics. This study aimed to understand the presence of pathogenic micro-organisms on the surface and core of chronically infected tonsils among Tanzanian children.
Methods
The study enrolled children undergoing adenotonsillectomy. Surface and core tonsillar swabs were taken. Quantitative polymerase chain reaction was performed for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, Neisseria meningitidis and Pseudomonas aeruginosa.
Results
Surface and core combined, isolated N meningitidis (86.1 per cent) was found the most, followed by H influenzae (74.9 per cent), S pneumoniae (42.6 per cent) and S aureus (28.7 per cent). M catarrhalis and P aeruginosa were only found in a few patients, 5.6 per cent and 0.8 per cent respectively.
Conclusion
Colonisation of the tonsillar surface and core has been found. Potentially pathogenic micro-organisms are likely to be missed based on a throat swab. Hence, the practice of surface tonsillar swabbing may be misleading or insufficient.
Traditional battery cages for laying hens will soon be banned in the EU but the increased risk of feather pecking (FP) hampers the adoption of alternative housing systems. FP can cause injury and lead to cannibalism and the painful death of target birds. Current management practices (beak trimming, low light) have associated problems. In a joint European project we sought alternative solutions. In our study of associated traits, birds from a line showing low (LFP) rather than high feather pecking (HFP) exhibited greater sociality (motivation to be near companions) and a passive ‘coping’ style. High sociality and passivity were also negatively associated with FP in adults. These findings may guide future breeding programs. Trimming hens’ feathers to mimic the results of FP elicited pecking and some cannibalism, even by birds that had previously shown no FP. Social transmission of gentle but not severe FP occurred when LFP and HFP birds were housed together. Gentle pecking could conceivably lead to severe FP. We then examined chickens’ pecking preferences to guide environmental enrichment strategies. Bunches of string elicited substantially greater interest than other stimuli, including feathers, and white or yellow string was the most attractive. The birds’ manipulation of the string resembled preening. Incorporating silver beads or moving the devices reduced pecking. String sustained lengthy interest, reduced FP in HFP birds, and decreased feather damage in caged layers on a commercial farm. String offers effective, affordable and practicable environmental enrichment. The integrated application of appropriate environmental and genetic strategies is likely to attenuate the expression of FP and its harmful consequences.
Social connectedness might positively influence the course of clinical symptoms in people with psychotic disorders.
Objectives
This study examines satisfaction with social connectedness (SSC) as predictor of positive and negative symptoms in people with a psychotic disorder.
Methods
Data from the Pharmacotherapy Monitoring and Outcome Survey (PHAMOUS, 2014-2019) was used from patients diagnosed with a psychotic disorder (N=2109). Items about social connectedness of the Manchester short assessment of Quality of Life (ManSA) were used to measure SSC. Linear mixed models were used to estimate the association of SSC with the Positive and Negative Syndrome Scale (PANSS) after one and two years against α=0.01. Analyses were adjusted for symptoms, time since onset, gender and age. Additionally, fluctuation of positive and negative symptom scores over time was estimated.
Results
Mean duration of illness of the sample was 18.8 years (SD 10.7) with >65% showing only small variation in positive and negative symptoms over a two to five-year time period. After adjustment for covariates, SSC showed to be negatively associated with positive symptoms after one year (β=-0.47, p<0.001, 95% CI=-0.70,-0.25) and two years (β =-0.59, p<0.001, 95% CI = -0.88,-0.30), and for negative symptoms after one year (β=-0.52, p<0.001, 95% CI = -0.77,-0.27). The prediction of negative symptoms was not significant at two years.
Conclusions
This research indicates that interventions on SSC might positively impact mental health for people with psychosis. SSC is a small and robust predictor of future levels of positive symptoms. Negative symptoms could be predicted by SSC at one year.
Most epidemiological studies show a decrease of internalizing disorders at older ages, but it is unclear how the prevalence exactly changes with age, and whether there are different patterns for internalizing symptoms and traits, and for men and women. This study investigates the impact of age and sex on the point prevalence across different mood and anxiety disorders, internalizing symptoms, and neuroticism.
Methods
We used cross-sectional data on 146 315 subjects, aged 18–80 years, from the Lifelines Cohort Study, a Dutch general population sample. Between 2012 and 2016, five current internalizing disorders – major depression, dysthymia, generalized anxiety disorder, social phobia, and panic disorder – were assessed according to DSM-IV criteria. Depressive symptoms, anxiety symptoms, neuroticism, and negative affect (NA) were also measured. Generalized additive models were used to identify nonlinear patterns across age, and to investigate sex differences.
Results
The point prevalence of internalizing disorders generally increased between the ages of 18 and 30 years, stabilized between 30 and 50, and decreased after age 50. The patterns of internalizing symptoms and traits were different. NA and neuroticism gradually decreased after age 18. Women reported more internalizing disorders than men, but the relative difference remained stable across age (relative risk ~1.7).
Conclusions
The point prevalence of internalizing disorders was typically highest between age 30 and 50, but there were differences between the disorders, which could indicate differences in etiology. The relative gap between the sexes remained similar across age, suggesting that changes in sex hormones around the menopause do not significantly influence women's risk of internalizing disorders.
Arctic mining has a bad reputation because the extractive industry is often responsible for a suite of environmental problems. Yet, few studies explore the gap between untouched tundra and messy megaproject from a historical perspective. Our paper focuses on Advent City as a case study of the emergence of coal mining in Svalbard (Norway) coupled with the onset of mining-related environmental change. After short but intensive human activity (1904–1908), the ecosystem had a century to respond, and we observe a lasting impact on the flora in particular. With interdisciplinary contributions from historical archaeology, archaeozoology, archaeobotany and botany, supplemented by stable isotope analysis, we examine 1) which human activities initially asserted pressure on the Arctic environment, 2) whether the miners at Advent City were “eco-conscious,” for example whether they showed concern for the environment and 3) how the local ecosystem reacted after mine closure and site abandonment. Among the remains of typical mining infrastructure, we prioritised localities that revealed the subtleties of long-term anthropogenic impact. Significant pressure resulted from landscape modifications, the import of non-native animals and plants, hunting and fowling, and the indiscriminate disposal of waste material. Where it was possible to identify individual inhabitants, these shared an economic attitude of waste not, want not, but they did not hold the environment in high regard. Ground clearances, animal dung and waste dumps continue to have an effect after a hundred years. The anthropogenic interference with the fell field led to habitat creation, especially for vascular plants. The vegetation cover and biodiversity were high, but we recorded no exotic or threatened plant species. Impacted localities generally showed a reduction of the natural patchiness of plant communities, and highly eutrophic conditions were unsuitable for liverworts and lichens. Supplementary isotopic analysis of animal bones added data to the marine reservoir offset in Svalbard underlining the far-reaching potential of our multi-proxy approach. We conclude that although damaging human–environment interactions formerly took place at Advent City, these were limited and primarily left the visual impact of the ruins. The fell field is such a dynamic area that the subtle anthropogenic effects on the local tundra may soon be lost. The fauna and flora may not recover to what they were before the miners arrived, but they will continue to respond to new post-industrial circumstances.
The characteristics of patients who have repeated compulsory psychiatric admissions are largely unknown.
Aims
To investigate the frequency and risk factors for repeated emergency compulsory psychiatric admission (ECPA); and to identify targets for interventions to reduce repeated ECPA.
Method
Data were collected from a database of electronic patient files (EPFs) held by three psychiatric emergency services (PES) in the Netherlands. Analyses were based on the data for adult patients (aged 18–75 years) with a first PES contact in 2010–2015. Using descriptive statistics and regression analysis, we studied the associations between baseline patient factors and repeated ECPA and time to readmission, within a 2-year follow-up period.
Results
We included 6059 patients: 15.6% had two or more ECPAs. In total, 66% of second ECPAs had occurred within 6 months of the first. About 30% of all ECPAs were repeated ECPAs. Two baseline factors were associated with a higher frequency of a second ECPA: history of receiving any mental healthcare treatment, whether in-patient or out-patient or both, and a lower level of self-care. Three were associated with a lower frequency: ethnicity (other than Dutch), older age and suicidality. Lower Global Assessment of Functioning (GAF) scores and housing problems were associated with a shorter time to compulsory readmission and persistent psychiatric problems with a longer time to compulsory readmission.
Conclusions
We found that 15.6% of patients had two or more ECPAs. Two-thirds of the second ECPAs had occurred within 6 months of the first. Like earlier studies, the risk factors we identified suggest that interventions to reduce the risk of repeated compulsory psychiatric admission should seek to improve self-care, general daily functioning and homelessness.
Epidemiological studies indicate that individuals with one type of mental disorder have an increased risk of subsequently developing other types of mental disorders. This study aimed to undertake a comprehensive analysis of pair-wise lifetime comorbidity across a range of common mental disorders based on a diverse range of population-based surveys.
Methods
The WHO World Mental Health (WMH) surveys assessed 145 990 adult respondents from 27 countries. Based on retrospectively-reported age-of-onset for 24 DSM-IV mental disorders, associations were examined between all 548 logically possible temporally-ordered disorder pairs. Overall and time-dependent hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards models. Absolute risks were estimated using the product-limit method. Estimates were generated separately for men and women.
Results
Each prior lifetime mental disorder was associated with an increased risk of subsequent first onset of each other disorder. The median HR was 12.1 (mean = 14.4; range 5.2–110.8, interquartile range = 6.0–19.4). The HRs were most prominent between closely-related mental disorder types and in the first 1–2 years after the onset of the prior disorder. Although HRs declined with time since prior disorder, significantly elevated risk of subsequent comorbidity persisted for at least 15 years. Appreciable absolute risks of secondary disorders were found over time for many pairs.
Conclusions
Survey data from a range of sites confirms that comorbidity between mental disorders is common. Understanding the risks of temporally secondary disorders may help design practical programs for primary prevention of secondary disorders.
Intermittent explosive disorder (IED) is characterised by impulsive anger attacks that vary greatly across individuals in severity and consequence. Understanding IED subtypes has been limited by lack of large, general population datasets including assessment of IED. Using the 17-country World Mental Health surveys dataset, this study examined whether behavioural subtypes of IED are associated with differing patterns of comorbidity, suicidality and functional impairment.
Methods
IED was assessed using the Composite International Diagnostic Interview in the World Mental Health surveys (n = 45 266). Five behavioural subtypes were created based on type of anger attack. Logistic regression assessed association of these subtypes with lifetime comorbidity, lifetime suicidality and 12-month functional impairment.
Results
The lifetime prevalence of IED in all countries was 0.8% (s.e.: 0.0). The two subtypes involving anger attacks that harmed people (‘hurt people only’ and ‘destroy property and hurt people’), collectively comprising 73% of those with IED, were characterised by high rates of externalising comorbid disorders. The remaining three subtypes involving anger attacks that destroyed property only, destroyed property and threatened people, and threatened people only, were characterised by higher rates of internalising than externalising comorbid disorders. Suicidal behaviour did not vary across the five behavioural subtypes but was higher among those with (v. those without) comorbid disorders, and among those who perpetrated more violent assaults.
Conclusions
The most common IED behavioural subtypes in these general population samples are associated with high rates of externalising disorders. This contrasts with the findings from clinical studies of IED, which observe a preponderance of internalising disorder comorbidity. This disparity in findings across population and clinical studies, together with the marked heterogeneity that characterises the diagnostic entity of IED, suggests that it is a disorder that requires much greater research.
There is a substantial proportion of patients who drop out of treatment before they receive minimally adequate care. They tend to have worse health outcomes than those who complete treatment. Our main goal is to describe the frequency and determinants of dropout from treatment for mental disorders in low-, middle-, and high-income countries.
Methods
Respondents from 13 low- or middle-income countries (N = 60 224) and 15 in high-income countries (N = 77 303) were screened for mental and substance use disorders. Cross-tabulations were used to examine the distribution of treatment and dropout rates for those who screened positive. The timing of dropout was examined using Kaplan–Meier curves. Predictors of dropout were examined with survival analysis using a logistic link function.
Results
Dropout rates are high, both in high-income (30%) and low/middle-income (45%) countries. Dropout mostly occurs during the first two visits. It is higher in general medical rather than in specialist settings (nearly 60% v. 20% in lower income settings). It is also higher for mild and moderate than for severe presentations. The lack of financial protection for mental health services is associated with overall increased dropout from care.
Conclusions
Extending financial protection and coverage for mental disorders may reduce dropout. Efficiency can be improved by managing the milder clinical presentations at the entry point to the mental health system, providing adequate training, support and specialist supervision for non-specialists, and streamlining referral to psychiatrists for more severe cases.
Episodic memory is impaired in Alzheimer’s disease (AD) dementia but thought to be relatively spared in behavioral variant frontotemporal dementia (bvFTD). This view is challenged by evidence of memory impairment in bvFTD. This study investigated differences in recognition memory performance between bvFTD and AD.
Method:
We performed a retrospective analysis on the recognition trial of the Rey Auditory Verbal Learning Test in patients with bvFTD (n = 85), AD (n = 55), and control participants (n = 59). Age- and education-adjusted between-group analysis was performed on the total score and indices of discriminative ability and response bias. Correlations between recognition and measures of memory, language, executive functioning, and construction were examined.
Results:
Patients with AD had a significantly lower total recognition score than patients with bvFTD (control 28.8 ± 1.5; bvFTD 24.8 ± 4.5; AD 23.4 ± 3.6, p < .01). Both bvFTD and AD had worse discriminative ability than controls (A’ control 0.96 ± 0.03; bvFTD 0.87 ± 0.03; AD 0.84 ± 0.10, p < .01), but there was no difference in response bias (B” control 0.9 ± 0.2; bvFTD 1.6 ± 1.47; AD 1.4± 1.4, p < .01). AD had worse discriminability than bvFTD (p < .05). Discriminability was associated with memory for both patient groups (median correlation coefficient r = .34) and additionally associated with language (r = .31), but not executive functioning (r = −.03) in bvFTD. Response bias was unrelated to other cognitive functions (r = −.02).
Conclusions:
Discriminability, but not response bias, differentiated patients with bvFTD from AD. The presence of an impaired discrimination index suggests a “pure” (recognition) memory deficit in bvFTD.
Despite important progress, the results of pharmacological treatment of schizophrenia are frequently unsatisfactory. Therefore some patients use natural medicines although it is unclear whether natural medicines are effective and safe. We assessed the evidence for natural medicines with and without antipsychotics in treating symptoms or reducing side effects of antipsychotics in schizophrenia.
Method:
A systematic review until April 2013. Only RCTs with a Jadad score of 3 or higher, were included.
Results:
105 RCTs were identified. Evidence was found for glycine, sarcosine, NAC, some Chinese and ayurvedic herbs, ginkgo biloba, estradiol and vitamin B6 for improving symptoms of schizophrenia when added to antipsychotics. Inconclusive or no evidence was found for omega-3, Dserine, D-alanine, D-cycloserine, B vitamins, vitamin C, dehydroepiandrosteron (DHEA), pregnenolone (PREG), inositol, gamma-hydroxybutyrate (GHB) and des-tyr-gamma-endorphin when added to antipsychotics. Omega-3 without antipsychotics might be beneficial in the prevention of schizophrenia. Only ayurvedic herbs (in one study), no other agents, seemed effective without antipsychotics. Ginkgo and vitamin B6 seemed to be effective in reducing side effects of antipsychotics. All natural agents produced only mild or no side-effects.
Conclusion:
High quality research on natural medicines for schizophrenia is scarce. However, there is emerging evidence for improved outcome for glycine, sarcosine, NAC, some Chinese and ayurvedic herbs, ginkgo biloba, estradiol and vitamin B6, all with only mild or no side effects. Most study samples are small, the study periods are generally short, the studies only cover a modest part of the world's population and most results need replication.
High rates of psychiatric comorbidity are subject of debate: to what extent do they depend on classification choices such as diagnostic thresholds?
Aims/objectives
To investigate the influence of different thresholds on rates of comorbidity between major depressive disorder (MDD) and generalized anxiety disorder (GAD).
Methods
Point prevalence of comorbidity between MDD and GAD was measured in 74,092 subjects from the general population according to DSM-IV-TR criteria. Comorbidity rates were compared for different thresholds by varying the number of necessary criteria from ≥ 1 to all 9 symptoms for MDD, and from ≥ 1 to all 7 symptoms for GAD.
Results
According to DSM-thresholds, 0.86% had MDD only, 2.96% GAD only and 1.14% both MDD and GAD (Odds Ratio [OR] 42.6). Lower thresholds for MDD led to higher rates of comorbidity (1.44% for ≥ 4 of 9 MDD-symptoms, OR 34.4), whereas lower thresholds for GAD hardly influenced comorbidity (1.16% for ≥ 3 of 7 GAD-symptoms, OR 38.8). Specific patterns in the distribution of symptoms within the population explained this finding: 37.3% of subjects with core criteria of MDD and GAD reported subthreshold MDD symptoms, whereas only 7.6% reported subthreshold GAD symptoms.
Conclusions
Lower thresholds for MDD increased comorbidity with GAD, but not vice versa, owing to specific symptom patterns in the population. Generally, comorbidity rates result from both empirical symptom distributions and classification choices and cannot be reduced to either of these exclusively. This insight invites further research into the formation of disease concepts that allow for reliable predictions and targeted therapeutic interventions.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Charles Bonnet syndrome (CBS) is a disorder in older adults, and is characterized by a triad of recurrent vivid visual hallucinations, ocular pathology causing visual impairment due to lesions in central or peripheral visual pathways, and normal cognitive status. It is often misdiagnosed as a psychosis, early dementia or a drug related condition. Hypoxemia was anecdotally reported as a cause of CBS.
Objectives
We present an older adult with CBS caused by severe obstructive sleep apnea syndrome.
Aims
To report a case study, describing treatment of obstructive sleep apnea syndrome as a cause of CBS.
Methods
A case study is presented and discussed.
Results
An older male adult was admitted to hospital for persistent vivid visual hallucinations. There was no personal or family history of mental illness. Neurological examination was normal, except for visual impairment due to age related macular degeneration. The remainder of his physical examination was normal. Previous treatment with antipsychotics proved not to be effective. Severe hypoxemia (SaO2 79%) was diagnosed with overnight pulse oximetry and subsequent polysomnography revealed an obstructive sleep apnea syndrome. After three nights of nasal continuous positive airway pressure, the vivid hallucinations ceased.
Conclusion
Physicians need to understand the underlying causes and mechanisms of CBS. One should be aware of the importance of a full clinical examination and sleep apnea research in elderly persons with visual impairment.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Data-driven techniques are frequently applied to identify subtypes of depression and anxiety. Although they are highly comorbid and often grouped under a single internalizing banner, most subtyping studies have focused on either depression or anxiety. Furthermore, most previous subtyping studies have not taken into account experienced disability.
Objectives
To incorporate disability into a data-driven cross-diagnostic subtyping model.
Aims
To capture heterogeneity of depression and anxiety symptomatology and investigate the importance of domain-specific disability-levels to distinguish between homogeneous subtypes.
Methods
Sixteen symptoms were assessed without skips using the MINI-interview in a population sample (LifeLines; n = 73403). Disability was measured with the RAND-36. To identify the best-fitting subtyping model, different nested latent variable models (latent class analysis, factor analysis and mixed-measurement item response theory [MM-IRT]) with and without disability covariates were compared. External variables were compared between the best model's classes.
Results
A five-class MM-IRT model incorporating disability showed the best fit (Fig. 1). Accounting for disability improved the differentiation between classes reporting isolated non-specific symptoms (“Somatic” [13.0%], and “Worried” [14.0%]) and those reporting more psychopathological symptoms (“Subclinical” [8.8%], and “Clinical” [3.3%]). A “Subclinical” class reported symptomatology at subthreshold levels. No pure depression or anxiety, but only mixed classes were observed.
Conclusions
An overarching subtyping model incorporating both symptoms and disability identified distinct cross-diagnostic subtypes. Diagnostic nets should be cast wider than current phenomenology-based categorical systems.
Figure not available.
Disclosure of interest
The authors have not supplied their declaration of competing interest.
Mental disorders are associated with lower subjective social status (SSS), but a more nuanced understanding of this relationship is needed. We examined the influence of disorder age of onset and recency on SSS and studied whether mental disorders are also associated with the discrepancy between actual and desired SSS.
Method
Data are from the baseline and second wave of the Netherlands Mental Health Survey and Incidence Study-2 (NEMESIS-2). Mental disorders were assessed with the Composite International Diagnostic Interview (CIDI 3.0), while both actual and desired SSS were assessed with a ten-rung ladder. Linear regression was used to examine the association between mental disorders and SSS.
Results
Of 5303 participants, 2237 had a lifetime mental disorder at baseline. These participants reported significantly lower actual SSS (6.28) at follow-up than healthy participants (6.66, B = −0.38 [95% CI −0.48 to −0.27], p < 0.001) and a significantly greater actual-desired SSS discrepancy (1.14 v. 1.05 after controlling for actual SSS, B = 0.09 [0.01–0.17], p = 0.024). Lower age of onset of the first mental disorder was marginally significantly associated with lower actual SSS (B = 0.006 [0.000–0.012], p = 0.046). More recent disorders were also associated with lower actual SSS (B = 0.015 [0.005–0.026], p = 0.005), such that participants whose disorder remitted ⩾6 years before baseline were statistically indistinguishable from healthy participants.
Conclusions
Lifetime mental disorders are associated with lower actual SSS and a slightly greater discrepancy between actual and desired SSS. However, people with mental disorders in (long-term) remission have a similar social status as healthy participants.
In Canada, recreational use of cannabis was legalized in October 2018. This policy change along with recent publications evaluating the efficacy of cannabis for the medical treatment of epilepsy and media awareness about its use have increased the public interest about this agent. The Canadian League Against Epilepsy Medical Therapeutics Committee, along with a multidisciplinary group of experts and Canadian Epilepsy Alliance representatives, has developed a position statement about the use of medical cannabis for epilepsy. This article addresses the current Canadian legal framework, recent publications about its efficacy and safety profile, and our understanding of the clinical issues that should be considered when contemplating cannabis use for medical purposes.
Compulsory admission is commonly regarded as necessary and justified for patients whose psychiatric condition represents a severe danger to themselves and others. However, while studies on compulsory admissions have reported on various clinical and social outcomes, little research has focused specifically on dangerousness, which in many countries is the core reason for compulsory admission.
Aims
To study changes in dangerousness over time in adult psychiatric patients admitted by compulsory court order, and to relate these changes to these patients' demographic and clinical characteristics.
Method
In this explorative prospective observational cohort study of adult psychiatric patients admitted by compulsory court order, demographic and clinical data were collected at baseline. At baseline and at 6 and 12 month follow-up, dangerousness was assessed using the Dangerousness Inventory, an instrument based on the eight types of dangerousness towards self or others specified in Dutch legislation on compulsory admissions. We used descriptive statistics and logistic regression to analyse the data.
Results
We included 174 participants with a court-ordered compulsory admission. At baseline, the most common dangerousness criterion was inability to cope in society. Any type of severe or very severe dangerousness decreased from 86.2% at baseline to 36.2% at 6 months and to 28.7% at 12 months. Being homeless at baseline was the only variable which was significantly associated with persistently high levels of dangerousness.
Conclusions
Dangerousness decreased in about two-thirds of the patients after court-ordered compulsory admission. It persisted, however, in a substantial minority (approximately one-third).
The aim of this study was to explore lameness and the associations between lameness and health/production measures of animal welfare in commercial broiler production, using the Welfare Quality® protocol for broilers. A total of 50 flocks were included in the sample and farm visits were conducted for lameness scoring at a mean age of 28.9 days. The percentage of animals (n=7500) in the six different gait score (GS) categories were GS0: 2.53%, GS1: 44.19%, GS2: 33.84%, GS3: 16.32%, GS4: 2.36% and GS5: 0.53%. Production and other welfare data were collected for each flock after slaughter. Higher gait scores were associated with increased hock burn score (P<0.02), increased footpad dermatitis score (P<0.01), reduced bird cleanliness score (P<0.01) and peat litter (P<0.01). Although not statistically significant, there was a tendency for increased flock gait score being associated with wet litter (P=0.07). In addition, condemnations at postmortem inspection were associated with increasing gait scores (P<0.05), indicating that at least a portion of the lameness cases display pathological changes on the carcasses. In conclusion, 19%of the birds showed moderate-to-severe lameness, which was associated with several production or health and welfare observations including feather cleanliness and condemnations as unfit for human consumption at slaughter. Although stocking density and growth rate are already known key factors for lameness, associations of lameness with hock burns, footpad dermatitis and cleanliness of the birds suggest that a suboptimal physical environment (e.g. litter- and air quality) may be detrimental to leg health. Further studies are needed to explore these associations in more detail.
Trends in structural and chemical leaf traits along a chronosequence of semi-evergreen tropical forest and their correlation with litter production and decomposition and associated carbon (C) and nitrogen (N) fluxes were assessed. Leaves of 15 dominant species in each plot were collected to measure leaf area, specific leaf area (SLA), C and N concentration and C:N ratio. Litterfall was measured and litter decomposition experiments were set up in 16 experimental plots in a chronosequence of secondary and mature forest. All five leaf traits combined discriminated the secondary forests from mature forest. SLA, N and C:N were significantly correlated to litter decomposition rates. Litter decomposition was significantly slower in mature forest compared with secondary forests. The N concentration of litter was lowest during the dry season, when litterfall was highest. N concentration in fresh leaves was higher than in litter, indicating that N is re-absorbed before leaf abscission. Leaf dynamics and associated nutrient cycling differ significantly between secondary forests and mature forest. Ecosystem-level leaf structural and chemical traits are good predictors of the stage of the forest and explain well the differences in decomposition rates between secondary and primary forests.