scholarly journals Virological factors that increase the transmissibility of emerging human viruses

2016 ◽  
Vol 113 (15) ◽  
pp. 4170-4175 ◽  
Author(s):  
Jemma L. Geoghegan ◽  
Alistair M. Senior ◽  
Francesca Di Giallonardo ◽  
Edward C. Holmes
Keyword(s):  
Recombination Frequency ◽  
Human Populations ◽  
Theoretic Approach ◽  
Genome Length ◽  
Emerging Infections ◽  
Animal Reservoir ◽  
Biological Features ◽  
Biological Variables ◽  
Host Mortality ◽  
Human Viruses

The early detection of pathogens with epidemic potential is of major importance to public health. Most emerging infections result in dead-end “spillover” events in which a pathogen is transmitted from an animal reservoir to a human but is unable to achieve the sustained human-to-human transmission necessary for a full-blown epidemic. It is therefore critical to determine why only some virus infections are efficiently transmitted among humans whereas others are not. We sought to determine which biological features best characterized those viruses that have achieved sustained human transmission. Accordingly, we compiled a database of 203 RNA and DNA human viruses and used an information theoretic approach to assess which of a set of key biological variables were the best predictors of human-to-human transmission. The variables analyzed were as follows: taxonomic classification; genome length, type, and segmentation; the presence or absence of an outer envelope; recombination frequency; duration of infection; host mortality; and whether or not a virus exhibits vector-borne transmission. This comparative analysis revealed multiple strong associations. In particular, we determined that viruses with low host mortality, that establish long-term chronic infections, and that are nonsegmented, nonenveloped, and, most importantly, not transmitted by vectors were more likely to be transmissible among humans. In contrast, variables including genome length, genome type, and recombination frequency had little predictive power. In sum, we have identified multiple biological features that seemingly determine the likelihood of interhuman viral transmissibility, in turn enabling general predictions of whether viruses of a particular type will successfully emerge in human populations.

scholarly journals Dances with worms: the ecological and evolutionary impacts of deworming on coinfecting pathogens

Parasitology ◽  
2013 ◽  
Vol 140 (9) ◽  
pp. 1119-1132 ◽  
Author(s):  
ANDY FENTON
Keyword(s):  
Helminth Infection ◽  
Integrated Management ◽  
Management Strategies ◽  
Context Dependency ◽  
Human Populations ◽  
Parasitic Helminths ◽  
Quantitative Level ◽  
Control Programmes ◽  
Quantitative Understanding ◽  
Host Mortality

SUMMARYParasitic helminths are ubiquitous in most host, including human, populations. Helminths often alter the likelihood of infection and disease progression of coinfecting microparasitic pathogens (viruses, bacteria, protozoa), and there is great interest in incorporating deworming into control programmes for many major diseases (e.g. HIV, tuberculosis, malaria). However, such calls are controversial; studies show the consequences of deworming for the severity and spread of pathogens to be highly variable. Hence, the benefits of deworming, although clear for reducing the morbidity due to helminth infection per se, are unclear regarding the outcome of coinfections and comorbidities. I develop a theoretical framework to explore how helminth coinfection with other pathogens affects host mortality and pathogen spread and evolution under different interspecific parasite interactions. In all cases the outcomes of coinfection are highly context-dependent, depending on the mechanism of helminth-pathogen interaction and the quantitative level of helminth infection, with the effects of deworming potentially switching from beneficial to detrimental depending on helminth burden. Such context-dependency may explain some of the variation in the benefits of deworming seen between studies, and highlights the need for obtaining a quantitative understanding of parasite interactions across realistic helminth infection ranges. However, despite this complexity, this framework reveals predictable patterns in the effects of helminths that may aid the development of more effective, integrated management strategies to combat pathogens in this coinfected world.

scholarly journals Evidence that Human Chlamydia pneumoniae Was Zoonotically Acquired

2009 ◽  
Vol 191 (23) ◽  
pp. 7225-7233 ◽  
Author(s):  
G. S. A. Myers ◽  
S. A. Mathews ◽  
M. Eppinger ◽  
C. Mitchell ◽  
K. K. O'Brien ◽  
...  
Keyword(s):  
Chlamydia Pneumoniae ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Populations ◽  
Animal Reservoir ◽  
Single Nucleotide ◽  
Phascolarctos Cinereus ◽  
Zoonotic Infections ◽  
Conserved Genes ◽  
Animal Isolate

ABSTRACT Zoonotic infections are a growing threat to global health. Chlamydia pneumoniae is a major human pathogen that is widespread in human populations, causing acute respiratory disease, and has been associated with chronic disease. C. pneumoniae was first identified solely in human populations; however, its host range now includes other mammals, marsupials, amphibians, and reptiles. Australian koalas (Phascolarctos cinereus) are widely infected with two species of Chlamydia, C. pecorum and C. pneumoniae. Transmission of C. pneumoniae between animals and humans has not been reported; however, two other chlamydial species, C. psittaci and C. abortus, are known zoonotic pathogens. We have sequenced the 1,241,024-bp chromosome and a 7.5-kb cryptic chlamydial plasmid of the koala strain of C. pneumoniae (LPCoLN) using the whole-genome shotgun method. Comparative genomic analysis, including pseudogene and single-nucleotide polymorphism (SNP) distribution, and phylogenetic analysis of conserved genes and SNPs against the human isolates of C. pneumoniae show that the LPCoLN isolate is basal to human isolates. Thus, we propose based on compelling genomic and phylogenetic evidence that humans were originally infected zoonotically by an animal isolate(s) of C. pneumoniae which adapted to humans primarily through the processes of gene decay and plasmid loss, to the point where the animal reservoir is no longer required for transmission.

scholarly journals Emergence of influenza A viruses

2001 ◽  
Vol 356 (1416) ◽  
pp. 1817-1828 ◽  
Author(s):  
R. J. Webby ◽  
R. G. Webster
Keyword(s):  
Intermediate Host ◽  
Influenza A ◽  
Influenza Viruses ◽  
Human Populations ◽  
Aquatic Bird ◽  
Intermediate Hosts ◽  
Aquatic Birds ◽  
Influenza A Viruses ◽  
Bird Populations ◽  
Human Viruses

Pandemic influenza in humans is a zoonotic disease caused by the transfer of influenza A viruses or virus gene segments from animal reservoirs. Influenza A viruses have been isolated from avian and mammalian hosts, although the primary reservoirs are the aquatic bird populations of the world. In the aquatic birds, influenza is asymptomatic, and the viruses are in evolutionary stasis. The aquatic bird viruses do not replicate well in humans, and these viruses need to reassort or adapt in an intermediate host before they emerge in human populations. Pigs can serve as a host for avian and human viruses and are logical candidates for the role of intermediate host. The transmission of avian H5N1 and H9N2 viruses directly to humans during the late 1990s showed that land-based poultry also can serve between aquatic birds and humans as intermediate hosts of influenza viruses. That these transmission events took place in Hong Kong and China adds further support to the hypothesis that Asia is an epicentre for influenza and stresses the importance of surveillance of pigs and live-bird markets in this area.

scholarly journals Hantavirus infections in The Netherlands: epidemiology and disease

1995 ◽  
Vol 114 (2) ◽  
pp. 373-383 ◽  
Author(s):  
J. Groen ◽  
M. N. Gerding ◽  
J. G. M. Jordans ◽  
J. P. Clement ◽  
J. H. M. Nieuwenhuijs ◽  
...  
Keyword(s):  
The Netherlands ◽  
Animal Species ◽  
Domestic Animal ◽  
Clethrionomys Glareolus ◽  
Human Populations ◽  
Animal Reservoir ◽  
Laboratory Findings ◽  
Transplant Patients ◽  
Forested Areas ◽  
Laboratory Workers

SummaryA serological survey for the prevalence of hantavirus infections in The Netherlands was carried out on > 10000 sera, from selected human populations, and different feral and domestic animal species. Hantavirus-specific antibodies were found in about 1% of patients suspected of acute leptospirosis, 10% of patients with acute nephropathia, and in less than 0·1% haemodialysis and renal transplant patients. Among individuals with a suspected occupational risk, 6% of animal trappers, 4% of forestry workers, 2% of laboratory workers and 0·4% of farmers were seropositive. The majority of the seropositive individuals lived in rural and forested areas. The main animal reservoir of the infection was shown to be the red bank vole (Clethrionomys glareolus). Epidemiological, clinical and laboratory findings seen in serologically confirmed human cases were similar to those associated with nephropathia epidemica.

scholarly journals Evolutionary origins of epidemic potential among human RNA viruses

2019 ◽  
Author(s):  
Lu Lu ◽  
Liam Brierley ◽  
Gail Robertson ◽  
Feifei Zhang ◽  
Samantha Lycett ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Rna Virus ◽  
Virus Genome ◽  
Human Populations ◽  
Infective Virus ◽  
Genome Sequences ◽  
Evolutionary Origins ◽  
Virus Diversity ◽  
Human Viruses ◽  
Do So

AbstractTo have epidemic potential, a pathogen must be able to spread in human populations, but of human-infective RNA viruses only a minority can do so. We investigated the evolution of human transmissibility through parallel analyses of 1755 virus genome sequences from 39 RNA virus genera. We identified 57 lineages containing human-transmissible species and estimated that at least 74% of these lineages have evolved directly from non-human viruses in other mammals or birds, a public health threat recently designated “Disease X”. Human-transmissible viruses rarely evolve from virus lineages that can infect but not transmit between humans. This result cautions against focussing surveillance and mitigation efforts narrowly on currently known human-infective virus lineages and supports calls for a better understanding of RNA virus diversity in non-human hosts.

scholarly journals Domestic Mammals as Reservoirs for Leishmania donovani on the Indian Subcontinent: Possibility and Consequences on Elimination

2020 ◽  
Author(s):  
Anurag Kushwaha ◽  
Breanna Scorza ◽  
Om Prakash Singh ◽  
Edgar Rowton ◽  
Philip Lawyer ◽  
...  
Keyword(s):  
Leishmania Donovani ◽  
Indian Subcontinent ◽  
Domestic Animals ◽  
Eastern Africa ◽  
Sand Fly ◽  
Detection Methods ◽  
Collaborative Group ◽  
Emerging Infections ◽  
Animal Reservoir ◽  
Domestic Species

Leishmania donovani is the causative agent of historically anthroponotic visceral leishmaniasis (VL) on the Indian subcontinent (ISC). L. donovani is transmitted by the sand fly species Phlebotomus argentipes. Our collaborative group and others have shown that sand flies trapped outside in endemic villages have fed on cattle and dogs in addition to people. Domestic animals are reservoirs for L. donovani complex spp., particularly L. infantum, in other endemic areas. Multiple studies using quantitative PCR or serological detection methods have demonstrated that goats, cattle, rats and dogs were diagnostically positive for L. donovani infection or exposure in eastern Africa, Bangladesh, Nepal and India. There is a limited understanding of the extent to which L. donovani infection of domestic animals drives transmission to other animals or humans on the ISC. Evidence from other vector-borne disease elimination strategies indicated that emerging infections in domestic species hindered eradication. The predominant lesson learned from these other situations is that non-human reservoirs must be identified, controlled and/or prevented. Massive efforts are underway for VL elimination on the Indian subcontinent. Despite these herculean efforts, residual VL incidence persists. The specter of an animal reservoir complicating elimination efforts haunts the final push toward full VL control. Better understanding of L. donovani transmission on the Indian subcontinent and rigorous consideration of how non-human reservoirs alter VL ecology are critical to sustain elimination goals.

Different Clinical Features but Not Outcome in SLL Patients Compared to CLL,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3896-3896
Author(s):  
Alejandra Martinez-Trillos ◽  
Eva Gine ◽  
Jordina Rovira ◽  
Marcos González ◽  
Maria Jose Terol ◽  
...  
Keyword(s):  
B Cells ◽  
Median Time ◽  
Who Classification ◽  
Conflicts Of Interest ◽  
Statistical Significance ◽  
Biological Features ◽  
Biological Variables ◽  
Richter Syndrome ◽  
Biological Studies

Abstract Abstract 3896 Chronic lymphocitytic leukaemia/Small lymphocytic lymphoma (CLL/SLL) is a neoplasm composed of monomorphic small neoplastic B cells that usually co-express CD5 and CD23. The current WHO classification considers CLL/SLL as the same entity being SLL the non-leukemic lymphoma presentation of CLL. The criteria for SLL include the presence of lymphadenopathy with less than 5×109/L peripheral blood B cells. Patients with SLL usually develop PB involvement during the evolution of the disease. The aim of this study was to analyze the main clinico-biological features and outcome of a series of SLL patients and compare them with the CLL patients diagnosed in the same period of time.Patients and methods: we have included 588 patients (353M/ 233F; median age 61 years) diagnosed with CLL or SLL according to the WHO classification criteria in the same period of time.The main clinico-biological features and the outcome were recorded and analysed according to the CLL/SLL diagnosis. Results: five hundred forty-five patients (93%) fulfil the criteria for CLL and 43 patients (7%) for SLL. The main clinico-biological variables according to the CLL/SLL criteria are detailed in the table. No differences were observed in gender distribution, age at diagnosis or ECOG. Patients with SLL had more frequently Binet C stage, low haemoglobin levels and platelet counts. 320 patients eventually received therapy, including purine analogues containing regimens (159 patients), chlorambucil (113), CHOP-like regimens (31), and other therapies (17). Sixty-nine patients received rituximab in combination. SLL patients received more frequently CHOP-like regimens than CLL patients, but this difference did not reach statistical significance. During the follow-up, 58% of the SLL patients eventually developed leukemic presentation, after a median time from diagnosis of 4.6 years (0.2–15 years). Patients with SLL not receiving treatment progressed to PB involvement sooner than treated SLL (median time, 1 year vs 6 year, respectively; p=0.06).Twenty four of the 588 patients eventually developed Richter syndrome, with this proportion being higher in the SLL than in CLL patients (13.1% vs 3.5%; p=0.001). Moreover, the proportion of second neoplasm (excluding non melanoma skin cancer) was higher for SLL patients than for CLL patients. After a median follow-up for surviving patients of 7.4 years (range, 0.1 to 28), 207 patients eventually died with no differences in overall survival between the two groups of patients. In addition, the causes of death were also similar (50% in SLL and 43% in CLL due to disease progression). In conclusion, although the outcome is similar in SLL and CLL groups, SLL patients more frequently had cytopenias as well as higher risk to develop Richter syndrome and second neoplasias. Genetic and other biological studies are warranted to elucidate the particular presentation and features of SLL.Patients (n=588)CLL (=545)SLL (n=43)pMedian age (years)6161Gender (Male/female)324/21929/14Binet C27/536 (5%)8/43 (18%)<0.001Hemoglobin <110 g/L26/526 (5%)7/39 (18%)0.001Platelets <100x109/L22/525 (4%)4/39 (10%)0.08High serum LDH (%)57/496 (11%)7/37 (18%)n.s.High B2 microglobuline191/442 (43%)17/32 (53%)n.s.High CD 38 expression135/484 (27%)18/38 (47%)0.011High ZAP 70 expression138/527 (26%)14/41 (34%)n.s.Unmutated IGHV160/335 (48%)10/15 (66%)n.s.Presence of Monoclonal Paraprotein28/545 (5%)4/43 (9%)n.s.Second Neoplasia (excluding Skin)74/545 (14%)11/43 (25%)0.03110-year risk of Richter Syndrome5.3%32.8%0.00110-year OS59%53.1%n.s. Disclosures: No relevant conflicts of interest to declare.

A GPI anchor explains the unique biological features of the common NKG2D-ligand allele MICA*008

2013 ◽  
Vol 454 (2) ◽  
pp. 295-302 ◽  
Author(s):  
Omodele Ashiru ◽  
Sheila López-Cobo ◽  
Lola Fernández-Messina ◽  
Samuel Pontes-Quero ◽  
Rachele Pandolfi ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Integral Membrane Protein ◽  
Biological Properties ◽  
Positive Pressure ◽  
Human Populations ◽  
Gene Encoding ◽  
Mhc I ◽  
Biological Features ◽  
Protein Receptor ◽  
Nucleotide Insertion

The human MICA (MHC I-related chain A) gene, encoding a ligand for the NKG2D (NKG2-D type II integral membrane protein) receptor, is highly polymorphic. A group of MICA alleles, named MICA 5.1 (prototype, MICA*008), produce a truncated protein due to a nucleotide insertion in the transmembrane domain. These alleles are very frequent in all of the human populations studied and they have different biological properties, compared with full-length alleles, e.g. recruitment into exosomes, which makes them very potent for down-modulating the NKG2D receptor in effector immune cells. Moreover, MICA*008 is not affected by viral immune evasion mechanisms that target other MICA alleles. In the present study, we demonstrate that MICA*008 acquires a GPI (glycosylphosphatidylinositol) anchor and that this modification is responsible for many of the distinct biological features of the truncated MICA alleles, including recruitment of the protein to exosomes. MICA*008 processing is also unusual as it is observed in the endoplasmic reticulum as a Triton™ X-114 soluble protein, partially undergoing GPI modification while the rest is exocytosed, suggesting a new model for MICA*008 release. This is the first report of a GPI-anchored MICA allele. The finding that this modification occurs in both families of human NKG2D ligands, as well as in the murine system, suggests positive pressure to maintain this biochemical feature.

scholarly journals Emotional Regulation In Teens And Improvement of Constructive Skills (EmoTIConS): Study Protocol For A Randomized Controlled Trial

2021 ◽  
Author(s):  
Laura Pedrini ◽  
Roberta Rossi ◽  
Laura Rosa Magni ◽  
Mariangela Lanfredi ◽  
Serena Meloni ◽  
...  
Keyword(s):  
Mental Health ◽  
Emotional Regulation ◽  
Emotional Problem ◽  
Skills Training ◽  
Control Group ◽  
Post Intervention ◽  
Adolescent Students ◽  
Biological Features ◽  
Biological Variables ◽  
The Impact

Abstract Background: Emotional dysregulation (ED) constitutes a relevant factor involved in the onset and maintenance of many mental disorders. Targeting ED during adolescence could be determinant both to identify high risk individuals and to promote preventive interventions. This study will aim to evaluate the impact of a brief Dialectical Behavioral Therapy (DBT)-based intervention for adolescent students by measuring changes in emotional regulation skills and impulsive behaviors. Moreover, alterations in biological features related to stress response and inflammation will be assessed as potential biological variables associated to ED.Methods: This is a randomized trial. A total of 20 classes of adolescent students will be recruited among high schools in Brescia, a city in the North of Italy. They will be randomized to the psychoeducational intervention (experimental group) or to a control condition (control group). The intervention will be based on DBT Skills Training for Emotional Problem Solving for Adolescents, and it will consist in four monthly 2-hours sessions (for a total of 8 hours) scheduled during regular school-time. Participants will be assessed at baseline, post-intervention, and at 3 and 6-month of follow-up. The primary outcome measures will be represented by changes in the use of emotional regulation skills (measured by the DBT-Ways of Coping Checklist) and by changes in the frequency of impulsive behaviours (measured by an ad-hoc created checklist). Salivary samples will be collected at baseline and post-intervention to explore possible biological features underlying ED.Discussion: Data from the present project will offer the opportunity to better understand the complex phenomenon of ED. Repeated assessment will cover several domains (emotional, behavioral, social, biological) as potential factors associated with ED. Moreover, it will be possible to measure the effect of the proposed intervention, contributing to improve knowledge on the impact of school-based universal preventive programs. Finally, the current trial will propose an integrated screening- and intervention-based model. Ultimately, this could reduce barriers to youth’s mental health care by fostering collaboration between schools and mental health services. Trial registration: ClinicalTrials.gov ID: NCT04349709. Registration date: 16/04/2020https://clinicaltrials.gov/ct2/show/NCT04349709

Genetic differences in recombination frequency in the pig (Sus scrofa)

Genome ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 1048-1051 ◽  
Author(s):  
L. Ollivierz
Keyword(s):  
General Result ◽  
Wild Species ◽  
Sus Scrofa ◽  
Recombination Frequency ◽  
Mammalian Species ◽  
Linkage Maps ◽  
Genome Length ◽  
Domestic Pig ◽  
Pig Genome ◽  
Wild Pig

A comparison has been performed on 3 recently published linkage maps of the pig, hereafter designated as the American (A), European (E), and Swedish (S) maps. The cumulated distances between common markers in these 3 maps were in the ratio 1.00 (A): 0.88 (E): 0.77 (S), in keeping with the ratio of the percentages of domestic genome in the reference families used to build the corresponding maps, i.e., 1.00 (A): 0.81 (E): 0.50 (S). From further recombination frequencies reported in wild boars (in the S report), the wild pig genome length (in centimorgans) is expected to represent 66% of the domestic pig genome length. These observations tend to confirm a general result of Burt and Bell (Nature (London), 326: 803–805 (1987)), showing higher chiasma frequencies in domestic mammalian species compared with wild species. Consequences for mapping studies are discussed.Key words: recombination, pig, microsatellites, chiasmata.

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