Prevalence of Helminths in Dogs and Owners’ Awareness of Zoonotic Diseases in Mampong, Ashanti, Ghana

Dogs are popular pets that live closely with humans. However, this cohabitation allows for the transmission of zoonotic parasites to humans. In Ghana, very little is known about zoonotic parasites in dogs. We examined excrements of 154 dogs for intestinal helminthes using saturated sodium chloride as a floatation medium and further interviewed 100 dog owners regarding knowledge on zoonosis and pet management practices. Thirteen parasite species were identified, with an overall prevalence of 52.6%. Nematodes were more common than cestodes, with Toxocara canis being the most prevalent helminth (18.8%). Age (p=0.011; χ2=9.034) and location (p=0.02; χ2=12.323) of dogs were significant risk factors of helminthic infections, while mode of housing, function, and gender of dogs were not. Knowledge on zoonosis and pet management practices were poor, including irregular deworming and feeding of animals off the bare ground. Dogs may play an active role in the transmission of zoonotic diseases in the area, given the cohabitation of infected dogs with humans; irregular deworming pattern of dogs; and rampant excretion of helminth-infested dog excreta into the environment

Globally, functional traits are weak predictors of juvenile tree growth, and we do not know why

1. Plant functional traits, in particular specific leaf area (SLA), wood density and seed mass, are often good predictors of individual tree growth rates within communities. Individuals and species with high SLA, low wood density and small seeds tend to have faster growth rates. 2. If community-level relationships between traits and growth have general predictive value, then similar relationships should also be observed in analyses that integrate across taxa, biogeographic regions and environments. Such global consistency would imply that traits could serve as valuable proxies for the complex suite of factors that determine growth rate, and, therefore, could underpin a new generation of robust dynamic vegetation models. Alternatively, growth rates may depend more strongly on the local environment or growth-trait relationships may vary along environmental gradients. 3. We tested these alternative hypotheses using data on 27352 juvenile trees, representing 278 species from 27 sites on all forested continents, and extensive functional trait data, 38% of which were obtained at the same sites at which growth was assessed. Data on potential evapotranspiration (PET), which summarizes the joint ecological effects of temperature and precipitation, were obtained from a global data base. 4. We estimated size-standardized relative height growth rates (SGR) for all species, then related them to functional traits and PET using mixed-effect models for the fastest growing species and for all species together. 5. Both the mean and 95th percentile SGR were more strongly associated with functional traits than with PET. PET was unrelated to SGR at the global scale. SGR increased with increasing SLA and decreased with increasing wood density and seed mass, but these traits explained only 3.1% of the variation in SGR. SGR-trait relationships were consistently weak across families and biogeographic zones, and over a range of tree statures. Thus, the most widely studied functional traits in plant ecology were poor predictors of tree growth over large scales. 6. Synthesis. We conclude that these functional traits alone may be unsuitable for predicting growth of trees over broad scales. Determining the functional traits that predict vital rates under specific environmental conditions may generate more insight than a monolithic global relationship can offer.Additional co-authors: Hervé Jactel, Xuefei Li, Kaoru Kitajima, Julia Koricheva, Cristina Martínez-Garza, Christian Messier, Alain Paquette, Christopher Philipson, Daniel Piotto, Lourens Poorter, Juan M. Posada, Catherine Potvin, Kalle Rainio, Sabrina E. Russo, Mariacarmen Ruiz-Jaen, Michael Scherer-Lorenzen, Campbell O. Webb, S. Joseph Wright, Rakan A. Zahawi, and Andy Hecto

Basic science232. Certolizumab pegol prevents pro-inflammatory alterations in endothelial cell function

Background: Cardiovascular disease is a major comorbidity of rheumatoid arthritis (RA) and a leading cause of death. Chronic systemic inflammation involving tumour necrosis factor alpha (TNF) could contribute to endothelial activation and atherogenesis. A number of anti-TNF therapies are in current use for the treatment of RA, including certolizumab pegol (CZP), (Cimzia ®; UCB, Belgium). Anti-TNF therapy has been associated with reduced clinical cardiovascular disease risk and ameliorated vascular function in RA patients. However, the specific effects of TNF inhibitors on endothelial cell function are largely unknown. Our aim was to investigate the mechanisms underpinning CZP effects on TNF-activated human endothelial cells. Methods: Human aortic endothelial cells (HAoECs) were cultured in vitro and exposed to a) TNF alone, b) TNF plus CZP, or c) neither agent. Microarray analysis was used to examine the transcriptional profile of cells treated for 6 hrs and quantitative polymerase chain reaction (qPCR) analysed gene expression at 1, 3, 6 and 24 hrs. NF-κB localization and IκB degradation were investigated using immunocytochemistry, high content analysis and western blotting. Flow cytometry was conducted to detect microparticle release from HAoECs. Results: Transcriptional profiling revealed that while TNF alone had strong effects on endothelial gene expression, TNF and CZP in combination produced a global gene expression pattern similar to untreated control. The two most highly up-regulated genes in response to TNF treatment were adhesion molecules E-selectin and VCAM-1 (q 0.2 compared to control; p > 0.05 compared to TNF alone). The NF-κB pathway was confirmed as a downstream target of TNF-induced HAoEC activation, via nuclear translocation of NF-κB and degradation of IκB, effects which were abolished by treatment with CZP. In addition, flow cytometry detected an increased production of endothelial microparticles in TNF-activated HAoECs, which was prevented by treatment with CZP. Conclusions: We have found at a cellular level that a clinically available TNF inhibitor, CZP reduces the expression of adhesion molecule expression, and prevents TNF-induced activation of the NF-κB pathway. Furthermore, CZP prevents the production of microparticles by activated endothelial cells. This could be central to the prevention of inflammatory environments underlying these conditions and measurement of microparticles has potential as a novel prognostic marker for future cardiovascular events in this patient group. Disclosure statement: Y.A. received a research grant from UCB. I.B. received a research grant from UCB. S.H. received a research grant from UCB. All other authors have declared no conflicts of interes

Wildfires as dominant force driving farming systems in the forest transition zone of Ghana

Wildfires have become very influential in the ecology and socio-economic aspects of the rural landscape in the transition zone of Ghana. Eight farming communities around four forest reserves with short fire-return intervals were studied to determine major changes in farming systems that can be attributed to wildfires. Results show that recurrent annual wildfires and other related factors have caused major changes in the farming systems of the study areas. Based on farmer perceptions, significant changes were found in the type of vegetation available for conversion into farms, site productivity, crops grown, labour input, and crop yields. Thick secondary forests with long rotations and high site productivity are no longer available for cultivation. They have been replaced with light grass and Chromolaena odorata fallow with short rotations and low site productivity. Other important changes are a dramatic shift from the growth of perennials (e.g. Cocoa) to annuals (e.g. maize), high labour requirements for land clearance, low crop yields, and a reduced interest in the cultivation of cocoa which used to be the backbone of the local economy. Farmers perceived these changes to be negative factors, implying that bush fires may be undermining agriculture beyond the physical destruction of farms and farm produce

Data from: Globally, functional traits are weak predictors of juvenile tree growth, and we do not know why

1. Plant functional traits, in particular specific leaf area (SLA), wood density and seed mass, are often good predictors of individual tree growth rates within communities. Individuals and species with high SLA, low wood density and small seeds tend to have faster growth rates. 2. If community-level relationships between traits and growth have general predictive value, then similar relationships should also be observed in analyses that integrate across taxa, biogeographic regions and environments. Such global consistency would imply that traits could serve as valuable proxies for the complex suite of factors that determine growth rate, and, therefore, could underpin a new generation of robust dynamic vegetation models. Alternatively, growth rates may depend more strongly on the local environment or growth–trait relationships may vary along environmental gradients. 3. We tested these alternative hypotheses using data on 27 352 juvenile trees, representing 278 species from 27 sites on all forested continents, and extensive functional trait data, 38% of which were obtained at the same sites at which growth was assessed. Data on potential evapotranspiration (PET), which summarizes the joint ecological effects of temperature and precipitation, were obtained from a global data base. 4. We estimated size-standardized relative height growth rates (SGR) for all species, then related them to functional traits and PET using mixed-effect models for the fastest growing species and for all species together. 5. Both the mean and 95th percentile SGR were more strongly associated with functional traits than with PET. PET was unrelated to SGR at the global scale. SGR increased with increasing SLA and decreased with increasing wood density and seed mass, but these traits explained only 3.1% of the variation in SGR. SGR–trait relationships were consistently weak across families and biogeographic zones, and over a range of tree statures. Thus, the most widely studied functional traits in plant ecology were poor predictors of tree growth over large scales. 6. Synthesis. We conclude that these functional traits alone may be unsuitable for predicting growth of trees over broad scales. Determining the functional traits that predict vital rates under specific environmental conditions may generate more insight than a monolithic global relationship can offer

Rainfall seasonality and drought performance shape the distribution of tropical tree species in Ghana

Tree species distribution in lowland tropical forests is strongly associated with rainfall amount and distribution. Not only plant water availability, but also irradiance, soilfertility, and pest pressure covary along rainfall gradients. To assess the role of wateravailability in shaping species distribution, we carried out a reciprocal transplantingexperiment in gaps in a dry and a wet forest site in Ghana, using 2,670 seedlings of23 tree species belonging to three contrasting rainfall distributions groups (dry species, ubiquitous species, and wet species). We evaluated seasonal patterns in climaticconditions, seedling physiology and performance (survival and growth) over a 2-yearperiod and related seedling performance to species distribution along Ghana's rainfall gradient. The dry forest site had, compared to the wet forest, higher irradiance,and soil nutrient availability and experienced stronger atmospheric drought (2.0 vs.0.6 kPa vapor pressure deficit) and reduced soil water potential (-5.0 vs.-0.6 MPasoil water potential) during the dry season. In both forests, dry species showed significantly higher stomatal conductance and lower leaf water potential, than wet species, and in the dry forest, dry species also realized higher drought survival andgrowth rate than wet species. Dry species are therefore more drought tolerant, andunlike the wet forest species, they achieve a home advantage. Species drought performance in the dry forest relative to the wet forest significantly predicted speciesposition on the rainfall gradient in Ghana, indicating that the ability to grow and survive better in dry forests and during dry seasons may allow species to occur in lowrainfall areas. Drought is therefore an important environmental filter that influencesforest composition and dynamics. Currently, many tropical forests experience increase in frequency and intensity of droughts, and our results suggest that this maylead to reduction in tree productivity and shifts in species distribution.</p

Performance of Ghanaian tree seedlings in terms of (a) survival and (b) relative biomass growth rate (RGR) in response to drought and shade.

<p>Shade treatments consisted of low light (5% of full sunlight, black bars) and high light (20% of full sunlight, grey bars). The water treatment consisted of a wet treatment (plants continuously watered for nine weeks) and dry treatment (water was withheld from seedlings for nine weeks). Means and standard error of the means are shown. Bars accompanied by a different letter are significantly different at P < 0.05 (ANOVA, Post hoc LSD test). n = 10 species.</p

List of ten tree species, their family, natural distribution and light requirements for regeneration (species guild).

<p>NPLD = non-pioneer light demander. Species guild and preference for a different forest type is based on [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121004#pone.0121004.ref049" target="_blank">49</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121004#pone.0121004.ref051" target="_blank">51</a>]. Average dry seed mass is based on [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121004#pone.0121004.ref052" target="_blank">52</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121004#pone.0121004.ref058" target="_blank">58</a>].</p><p>List of ten tree species, their family, natural distribution and light requirements for regeneration (species guild).</p

Seedling leaf physiological traits: (a) stomatal conductance (g_s), (b) midday leaf water potential (ψ_mid) of plants from which water was withheld and plants that received daily watering for 9 weeks in 5% of full sunlight (black bars) and 20% of full sunlight (grey bars).

<p>Bars are means and error bars are standard errors of the means.</p