106 research outputs found
Forecasting Population Changes and Service Requirements in the Regions: A Study of Two Regional Councils in Queensland, Australia
Forecasting population growth to meet the service needs of a growing population is a vexed issue. The task of providing essential services becomes even more difficult when future population growth forecasts are unavailable or unreliable. The aim of this paper is to identify the main methods used in population forecasting and thereby select an approach to demonstrate that such forecasting can be undertaken with certainly and transparency, barring exogenous events. We then use the population forecasts to plan for service needs that arise from changes in population in the future. Interestingly, although there are techniques available to forecast such future population changes and much of this forecasting occurs, such work remains somewhat clouded in mystery. We strive to rectify this situation by applying an approach that is verifiable, transparent, and easy to comprehend. For this purpose we select two regional councils in Queensland, Australia. The experience derived from forecasting shows that forecasts for service needs of larger populations are more easily and accurately derived than for smaller populations. Hence, there is some evidence, at least from a service provision point of view, to justify the benefits of council/municipality amalgamation in recent times in Australia and elsewhere. The methodology used in this paper for population forecasting and the provision of service needs based on such forecasts will be of particular interest to policy decision-makers and planners.Regional Population forecasting, service provision, Box-Jenkins model
Forecasting population changes and service requirements in the regions: a study of two regional councils in Queensland, Australia
Forecasting population growth to meet the service needs of a growing population is a vexed issue. The task of providing essential services becomes even more difficult when future population growth forecasts are unavailable or unreliable. The aim of this paper is to identify the main methods used in population forecasting and thereby select an approach to demonstrate that such forecasting can be undertaken with certainly and transparency, barring exogenous events. We then use the population forecasts to plan for service needs that arise from changes in population in the future. Interestingly, although there are techniques available to forecast such future population changes and much of this forecasting occurs, such work remains somewhat clouded in mystery. We strive to rectify this situation by applying an approach that is verifiable, transparent, and easy to comprehend. For this purpose we select two regional councils in Queensland, Australia. The experience derived from forecasting shows that forecasts for service needs of larger populations are more easily and accurately derived than for smaller populations. Hence, there is some evidence, at least from a service provision point of view, to justify the benefits of council/ municipality amalgamation in recent times in Australia and elsewhere. The methodology used in this paper for population forecasting and the provision of service needs based on such forecasts will be of particular interest to policy decisionmakers and planners.Regional Population forecasting, service provision, Box-Jenkins model
First Complete Cytochrome B Sequences and Molecular Taxonomy of Bat Species from Sri Lanka
The aim of our study was to address the research gap in the molecular taxonomy of Sri Lankan bats. The accurate identification of animals plays a major role in observing them in their natural environments and hence understanding possible disease-transmitting pathways from animals to humans. Being a tropical country, Sri Lanka has a high density of animals. There are 30 different species of bats described in Sri Lanka. Until now, the animals have been identified by observing their physical features. However, the visual identification of animals is not accurate because closely related animal groups may show similar physical features. During our study, we accurately differentiated five bat groups living in one of the largest caves in Sri Lanka by using a more sophisticated laboratory technique. Using molecular techniques, we were able to provide more accurate results than by the visual identification of the bats. The results from our study are stored in the NCBI database as a baseline for a repository of Sri Lankan bats. With the new sequence data provided here, we filled the gap concerning the molecular taxonomy of bat species of the entire region and we contributed to the future conservation and systematic studies of these mammalsThis is the first report on the molecular identification and phylogeny of the Rousettus leschenaultii Desmarest, 1810, Rhinolophus rouxii Temminck, 1835, Hipposideros speoris Schneider, 1800, Hipposideros lankadiva Kelaart, 1850, and Miniopterus fuliginosus Kuhl, 1817, bat species in Sri Lanka, inferred from analyses by mitochondrially encoded cytochrome b gene sequences. Recent research has indicated that bats show enormous cryptic genetic diversity. Moreover, even within the same species, the acoustic properties of echolocation calls and morphological features such as fur color could vary in different populations. Therefore, we have used molecular taxonomy for the accurate identification of five bat species recorded in one of the largest cave populations in Sri Lanka. The bats were caught using a hand net, and saliva samples were collected non-invasively from each bat by using a sterile oral swab. Nucleic acids were extracted from the oral swab samples, and mitochondrial DNA was amplified by using primers targeting the mitochondrially encoded cytochrome b gene. This study reports the first molecular evidence for the identification of five bat species in Sri Lanka. Our findings will contribute to future conservation and systematic studies of bats in Sri Lanka. This study will also provide the basis for a genetic database of Sri Lankan bats which will contribute significantly to the investigation of potentially zoonotic bat viruses.Peer Reviewe
Paramyxovirus Diversity within One Population of Miniopterus fuliginosus Bats in Sri Lanka
Bats are known as typical reservoirs for a number of viruses, including viruses of the family Paramyxoviridae. Representatives of the subfamily Orthoparamyxovirinae are distributed worldwide and can cause mild to fatal diseases when infecting humans. The research on Paramyxoviruses (PMVs) from different bat hosts all over the world aims to understand the diversity, evolution and distribution of these viruses and to assess their zoonotic potential. A high number of yet unclassified PMVs from bats are recorded. In our study, we investigated bat species from the families Rhinolophidae, Hipposiderae, Pteropodidae and Miniopteridae that are roosting sympatrically in the Wavul Galge cave (Koslanda, Sri Lanka). The sampling at three time points (March and July 2018; January 2019) and screening for PMVs with a generic PCR show the presence of different novel PMVs in 10 urine samples collected from Miniopterus fuliginosus. Sequence analysis revealed a high similarity of the novel strains among each other and to other unclassified PMVs collected from Miniopterus bats. In this study, we present the first detection of PMVs in Sri Lanka and the presence of PMVs in the bat species M. fuliginosus for the first time.Peer Reviewe
Full Genome of batCoV/MinFul/2018/SriLanka, a Novel Alpha-Coronavirus Detected in Miniopterus fuliginosus, Sri Lanka
Coronaviruses (CoV) are divided into the genera α-CoVs, β-CoVs, γ-CoVs and δ-CoVs. Of these, α-CoVs and β-CoVs are solely capable of causing infections in humans, resulting in mild to severe respiratory symptoms. Bats have been identified as natural reservoir hosts for CoVs belonging to these two genera. Consequently, research on bat populations, CoV prevalence in bats and genetic characterization of bat CoVs is of special interest to investigate the potential transmission risks. We present the genome sequence of a novel α-CoV strain detected in rectal swab samples of Miniopterus fuliginosus bats from a colony in the Wavul Galge cave (Koslanda, Sri Lanka). The novel strain is highly similar to Miniopterus bat coronavirus 1, an α-CoV located in the subgenus of Minunacoviruses. Phylogenetic reconstruction revealed a high identity of the novel strain to other α-CoVs derived from Miniopterus bats, while human-pathogenic α-CoV strains like HCoV-229E and HCoV-NL63 were more distantly related. Comparison with selected bat-related and human-pathogenic strains of the β-CoV genus showed low identities of ~40%. Analyses of the different genes on nucleotide and amino acid level revealed that the non-structural ORF1a/1b are more conserved among α-CoVs and β-CoVs, while there are higher variations in the structural proteins known to be important for host specificity. The novel strain was named batCoV/MinFul/2018/SriLanka and had a prevalence of 50% (66/130) in rectal swab samples and 58% (61/104) in feces samples that were collected from Miniopterus bats in Wavul Galge cave. Based on the differences between strain batCoV/MinFul/2018/SriLanka and human-pathogenic α-CoVs and β-CoVs, we conclude that there is a rather low transmission risk to humans. Further studies in the Wavul Galge cave and at other locations in Sri Lanka will give more detailed information about the prevalence of this virus.Peer Reviewe
Chromium Induced Histological Changes in the Body Wall of the Earthworm Eudrillus eugeniae
In Sri Lanka, documented evidence indicates that the Chromium (Cr) content in water andsoil is high, reaching upto 0.60 mgl-1 in water and 103 mg kg-1 in soil and sediment. Cr is oneof the most toxic heavy metals, which is capable of inducing adverse effects in exposedorganisms even in trace amounts. Of the two valency states, Cr3+ and Cr6+, the latter ispotentially more toxic than the former. In the present study we examined the histologicalalterations in the body wall of Eudrillus eugeniae, a commonly occurring species ofearthworm, exposed to hexa-valent Cr.Adult earthworms were collected from a culture facility in Talawakalle, and acclimatized fortwo weeks. Worms with a well-developed clitellum and of 0.29 + 0.009 g weight were usedfor standard chronic exposure trials of 28 days. For the trials, the animals were placed insuitably prepared clay pots containing banana piths soaked in five different concentrations(0.002 – 20 mg l-1) of Cr6+. At the end of the 28 days, the worms were fixed in Zenkerfixative, washed, dehydrated, embedded in paraffin wax and the tissue sections taken at7 μmwere stained using hematoxylin-eosin. Histological alterations in the outer epithelium werethen recorded in detail.It was evident that Cr6+ induced alterations in the outer epithelium of the earthworm at all testlevels. A reduction in the thickness of the epithelium was noted (Control – 61.6 ± 6.1μm,0.02 mg l-1 – 28.0 ± 1.5 μm). Another observation was the reduction in the number of nuclei(Control – 31.3 ± 2.8, 0.02 mg l-1 - 7.4 ± 0.4) and the increase in the number of pyknoticnuclei in a given area of epithelial tissue (Control - 2.3 ± 0.4, 0.002 mg l-1 - 10.5 ± 1.0).Epithelial cells were neatly compacted with distinct cell margins in earthworms that were notexposed, whilst those exposed showed disintegration of cell margins even at 0.002 mg l-1 ofCr6+. Mucous cells, which are generally apparent, were not distinct in Cr6+ treated worms.Epithelial sloughing was more pronounced in treated earthworms than in the controls. Thespace between the epidermis and muscle layers were greater in treated worms than in thecontrols (Control - 0.7 ± 0.5 μm, 0.02 mg l-1 - 23.6 ± 1.0 μm). The muscle layers of the bodywall of the Cr6+ treated worms showed loss of structural integrity and increased intercellularspaces with the damage being more severe in those exposed to 20 mg l-1. This study providesevidence that histopathological alterations are possible in the earthworm at levels of Crrecorded in Sri Lanka’s natural ecosystems.
Dengue type 1 viruses circulating in humans are highly infectious and poorly neutralized by human antibodies
The four dengue virus (DENV) serotypes are mosquito-borne flaviviruses of humans. The interactions between DENVs and the human host that lead to asymptomatic, mild, or severe disease are poorly understood, in part, because laboratory models are poor surrogates for human DENV disease. Virologists are interested in how the properties of DENVs replicating in people compare with virions propagated on laboratory cell lines, which are widely used for research and vaccine development. Using clinical samples from a DENV type 1 epidemic in Sri Lanka and new ultrasensitive assays, we compared the properties of DENVs in human plasma and after one passage on laboratory cell lines. DENVs in plasma were 50- to 700-fold more infectious than cell culture-grown viruses. DENVs produced by laboratory cell lines were structurally immature and hypersensitive to neutralization by human antibodies compared with DENVs circulating in people. Human plasma and cell culture-derived virions had identical genome sequences, indicating that these phenotypic differences were due to the mature state of plasma virions. Several dengue vaccines are under development. Recent studies indicate that vaccine-induced antibodies that neutralized DENVs in cell culture assays were not sufficient for protecting people from DENV infections. Our results about structural differences between DENVs produced in humans versus cell lines may be key to understanding vaccine failure and developing better models for vaccine evaluation
Immunity against sexual stage Plasmodium falciparum and Plasmodium vivax parasites.
The efficient spread of malaria from infected humans to mosquitoes is a major challenge for malaria elimination initiatives. Gametocytes are the only Plasmodium life stage infectious to mosquitoes. Here, we summarize evidence for naturally acquired anti-gametocyte immunity and the current state of transmission blocking vaccines (TBV). Although gametocytes are intra-erythrocytic when present in infected humans, developing Plasmodium falciparum gametocytes may express proteins on the surface of red blood cells that elicit immune responses in naturally exposed individuals. This immune response may reduce the burden of circulating gametocytes. For both P. falciparum and Plasmodium vivax, there is a solid evidence that antibodies against antigens present on the gametocyte surface, when co-ingested with gametocytes, can influence transmission to mosquitoes. Transmission reducing immunity, reducing the burden of infection in mosquitoes, is a well-acknowledged but poorly quantified phenomenon that forms the basis for the development of TBV. Transmission enhancing immunity, increasing the likelihood or intensity of transmission to mosquitoes, is more speculative in nature but is convincingly demonstrated for P. vivax. With the increased interest in malaria elimination, TBV and monoclonal antibodies have moved to the center stage of malaria vaccine development. Methodologies to prioritize and evaluate products are urgently needed
Merozoite surface protein-3α is a reliable marker for population genetic analysis of Plasmodium vivax
BACKGROUND: The knowledge on population structure of the parasite isolates has contributed greatly to understanding the dynamics of the disease transmission for designing and evaluating malaria vaccines as well as for drug applications. msp-1 and msp-3α genes have been used as a genetic marker in population studies of Plasmodium vivax isolates. In this study, msp-3α was compared and assessed with msp-1 marker in order to find whether msp-3α is a reliable genetic marker for P. vivax population studies. METHODS: This comparative study was designed and carried out as the first assessment of diversity in Pvmsp-3α gene by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in the 50 northern and 94 southern P. vivax isolates from Iran, which had been analysed before for msp-1 gene. RESULTS: Three allele size as, Type A (1.8 kb), Type B (1.5 kb) and Type C (1.2 kb) have been detected among both northern and southern isolates based on PCR results. Type C (70%) and Type A (68.7%) were the predominant fragments among northern and southern parasites, respectively. 99 distinct Pvmsp-3α fragments defined by the size were detected in the 94 southern samples by PCR analysis. However, no mixed genotype infections have been detected among northern isolates. Based on restriction pattern from digestion with Hha I and Alu I 12 and 49 distinct allelic variants have been detected among 50 northern and 94 southern isolates. However, based on msp-1 gene, 30 distinct variants identified in all 146-sequenced Iranian P. vivax isolate. CONCLUSION: The results suggested that PCR-RFLP on msp-3α gene is an adequate, applicable and easily used technique for molecular epidemiology studies of P. vivax isolates without the need for further sequencing analysis
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