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1.
Environ Res ; 233: 116416, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37321337

RESUMO

The concept of environmental "spillover" of pathogens to humans is widely used in the scientific literature about emerging diseases with the idea that it is scientifically proven. However, the exact characterization of the mechanism of spillover is simply lacking. A systematic review retrieved 688 articles using this term. The systematic analysis revealed an irreducible polysemy covering ten different definitions. It also demonstrated the absence of explicit definition in most of the articles, and even antinomies. A modeling analysis of the various processes described by these ten definitions showed that none of them corresponded to the complete trajectory leading to the emergence of a disease. There is no article demonstrating a mechanism of spillover. There are only ten articles proposing ideas on how a putative spillover could work but they merely are intellectual constructions. All other articles only reuse the term with no demonstration. It is essential to understand that since there is no scientific concept behind the "spillover", it might be dangerous to base public health and public protection against future pandemics on it.


Assuntos
Doenças Transmissíveis Emergentes , Vírus , Animais , Humanos , Zoonoses , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/prevenção & controle , Saúde Pública , Pandemias
2.
Environ Res ; 207: 112173, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626592

RESUMO

Since the beginning of the COVID-19 pandemic in 2020 caused by SARS-CoV-2, the question of the origin of this virus has been a highly debated issue. Debates have been, and are still, very disputed and often violent between the two main hypotheses: a natural origin through the "spillover" model or a laboratory-leak origin. Tenants of these two options are building arguments often based on the discrepancies of the other theory. The main problem is that it is the initial question of the origin itself which is biased. Charles Darwin demonstrated in 1859 that all species are appearing through a process of evolution, adaptation and selection. There is no determined origin to any animal or plant species, simply an evolutionary and selective process in which chance and environment play a key role. The very same is true for viruses. There is no determined origin to viruses, simply also an evolutionary and selective process in which chance and environment play a key role. However, in the case of viruses the process is slightly more complex because the "environment" is another living organism. Pandemic viruses already circulate in humans prior to the emergence of a disease. They are simply not capable of triggering an epidemic yet. They must evolve in-host, i.e. in-humans, for that. The evolutionary process which gave rise to SARS-CoV-2 is still ongoing with regular emergence of novel variants more adapted than the previous ones. The real relevant question is how these viruses can emerge as pandemic viruses and what the society can do to prevent the future emergence of pandemic viruses.


Assuntos
COVID-19 , Vírus , Animais , Humanos , Pandemias , SARS-CoV-2
3.
Environ Res ; 204(Pt B): 112141, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34597664

RESUMO

The origin of SARS-CoV-2 is still the subject of a controversial debate. The natural origin theory is confronted to the laboratory leak theory. The latter is composite and comprises contradictory theories, one being the leak of a naturally occurring virus and the other the leak of a genetically engineered virus. The laboratory leak theory is essentially based on a publication by Rahalkar and Bahulikar in 2020 linking SARS-CoV-2 to the Mojiang mine incident in 2012 during which six miners fell sick and three died. We analyzed the clinical reports. The diagnosis is not that of COVID-19 or SARS. SARS-CoV-2 was not present in the Mojiang mine. We also bring arguments against the laboratory leak narrative.


Assuntos
COVID-19 , Acidentes , Humanos , Laboratórios , SARS-CoV-2
4.
Environ Res ; 202: 111676, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34252435

RESUMO

The whole human society was caught unprepared by the emergence of SARS-CoV-2 and the related COVID-19 pandemic. This should have not been. We already had on hand all information to organize properly and prevent this emergence. However, this information was never translated into preparedness because the current system of sanitary crises management is not adapted. We keep implementing a medical, symptomatic, post-emergence approach which cannot stop an emerging pandemic. The only preventive action considered is the screening for viruses in the wild but it is not efficient since pandemic viruses do not exist in the wild, and indeed, have never been found. The emergence of a viral pandemic is the result of a double accident: the in-host evolution of the causative virus and its amplification to the epidemic threshold by societal factors. To be prepared the society should target this societal dimension of emerging diseases and organize accordingly. Unfortunately, the society is not organized that way and is still unprepared and vulnerable.


Assuntos
COVID-19 , Doenças Transmissíveis Emergentes , Doenças Transmissíveis Emergentes/epidemiologia , Humanos , Pandemias , SARS-CoV-2
5.
BMC Microbiol ; 20(1): 188, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32605600

RESUMO

BACKGROUND: Wolbachia are the most widely spread endosymbiotic bacteria, present in a wide variety of insects and two families of nematodes. As of now, however, relatively little genomic data has been available. The Wolbachia symbiont can be parasitic, as described for many arthropod systems, an obligate mutualist, as in filarial nematodes or a combination of both in some organisms. They are currently classified into 16 monophyletic lineage groups ("supergroups"). Although the nature of these symbioses remains largely unknown, expanded Wolbachia genomic data will contribute to understanding their diverse symbiotic mechanisms and evolution. RESULTS: This report focuses on Wolbachia infections in three pseudoscorpion species infected by two distinct groups of Wolbachia strains, based upon multi-locus phylogenies. Geogarypus minor harbours wGmin and Chthonius ischnocheles harbours wCisc, both closely related to supergroup H, while Atemnus politus harbours wApol, a member of a novel supergroup S along with Wolbachia from the pseudoscorpion Cordylochernes scorpioides (wCsco). Wolbachia supergroup S is most closely related to Wolbachia supergroups C and F. Using target enrichment by hybridization with Wolbachia-specific biotinylated probes to capture large fragments of Wolbachia DNA, we produced two draft genomes of wApol. Annotation of wApol highlights presence of a biotin operon, which is incomplete in many sequenced Wolbachia genomes. CONCLUSIONS: The present study highlights at least two symbiont acquisition events among pseudoscorpion species. Phylogenomic analysis indicates that the Wolbachia from Atemnus politus (wApol), forms a separate supergroup ("S") with the Wolbachia from Cordylochernes scorpioides (wCsco). Interestingly, the biotin operon, present in wApol, appears to have been horizontally transferred multiple times along Wolbachia evolutionary history.


Assuntos
Aracnídeos/microbiologia , Biotina/genética , Sequenciamento Completo do Genoma/métodos , Wolbachia/classificação , Animais , Transferência Genética Horizontal , Tamanho do Genoma , Genoma Bacteriano , Anotação de Sequência Molecular , Tipagem de Sequências Multilocus , Óperon , Filogenia , Simbiose , Wolbachia/genética , Wolbachia/isolamento & purificação
6.
BMC Infect Dis ; 17(1): 333, 2017 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-28482808

RESUMO

BACKGROUND: In 2011-2012, Northern Vietnam experienced its first large scale hand foot and mouth disease (HFMD) epidemic. In 2011, a major HFMD epidemic was also reported in South Vietnam with fatal cases. This 2011-2012 outbreak was the first one to occur in North Vietnam providing grounds to study the etiology, origin and dynamic of the disease. We report here the analysis of the VP1 gene of strains isolated throughout North Vietnam during the 2011-2012 outbreak and before. METHODS: The VP1 gene of 106 EV-A71 isolates from North Vietnam and 2 from Central Vietnam were sequenced. Sequence alignments were analyzed at the nucleic acid and protein level. Gene polymorphism was also analyzed. A Factorial Correspondence Analysis was performed to correlate amino acid mutations with clinical parameters. RESULTS: The sequences were distributed into four phylogenetic clusters. Three clusters corresponded to the subgenogroup C4 and the last one corresponded to the subgenogroup C5. Each cluster displayed different polymorphism characteristics. Proteins were highly conserved but three sites bearing only Isoleucine (I) or Valine (V) were characterized. The isoleucine/valine variability matched the clusters. Spatiotemporal analysis of the I/V variants showed that all variants which emerged in 2011 and then in 2012 were not the same but were all present in the region prior to the 2011-2012 outbreak. Some correlation was found between certain I/V variants and ethnicity and severity. CONCLUSIONS: The 2011-2012 outbreak was not caused by an exogenous strain coming from South Vietnam or elsewhere but by strains already present and circulating at low level in North Vietnam. However, what triggered the outbreak remains unclear. A selective pressure is applied on I/V variants which matches the genetic clusters. I/V variants were shown on other viruses to correlate with pathogenicity. This should be investigated in EV-A71. I/V variants are an easy and efficient way to survey and identify circulating EV-A71 strains.


Assuntos
Proteínas do Capsídeo/genética , Enterovirus Humano A/genética , Doença de Mão, Pé e Boca/virologia , Pré-Escolar , Surtos de Doenças , Enterovirus/isolamento & purificação , Enterovirus Humano A/isolamento & purificação , Enterovirus Humano A/patogenicidade , Epidemias , Feminino , Doença de Mão, Pé e Boca/epidemiologia , Humanos , Lactente , Isoleucina , Masculino , Mutação , Filogenia , Polimorfismo Genético , Seleção Genética , Análise Espaço-Temporal , Valina , Vietnã/epidemiologia
7.
China CDC Wkly ; 6(12): 225-229, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38633431

RESUMO

What is already known about this topic?: Given the challenges presented by drug-resistant strains of tuberculosis (TB) and the rising mobility of the population, achieving the objective of eradicating TB appears uncertain. What is added by this report?: The examination of TB incidence trends in 10 high-burden countries (HBCs) indicated a steady rise in cases, with India and China jointly accounting for nearly 70% of the burden. Projections for the future show diverse trajectories in these countries, with potential difficulties in reaching the TB elimination target, especially in Nigeria, Congo, and South Africa. What are the implications for public health practice?: The number of TB cases is on the rise. It is crucial to learn from successful strategies to improve TB prevention and control worldwide through collaborative efforts.

8.
PLoS Negl Trop Dis ; 18(5): e0012131, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38743784

RESUMO

BACKGROUND: Echinococcosis is a natural focal, highly prevalent disease in China. Factors influencing the spread of echinococcosis are not only related to personal exposure but also closely related to the environment itself. The purpose of this study was to explore the influence of environmental factors on the prevalence of human echinococcosis and to provide a reference for prevention and control of echinococcosis in the future. METHODS: Data were collected from 370 endemic counties in China in 2018. By downloading Modis, DEM and other remote-sensing images in 2018. Data on environmental factors, i.e., elevation, land surface temperature (LST) and normalized difference vegetation index (NDVI) were collected. Rank correlation analysis was conducted between each environmental factor and the prevalence of echinococcosis at the county level. Negative binomial regression was used to analyze the impact of environmental factors on the prevalence of human echinococcosis at the county level. RESULTS: According to rank correlation analysis, the prevalence of human echinococcosis in each county was positively correlated with elevation, negatively correlated with LST, and negatively correlated with NDVI in May, June and July. Negative binomial regression showed that the prevalence of human echinococcosis was negatively correlated with annual LST and summer NDVI, and positively correlated with average elevation and dog infection rate. The prevalence of human cystic echinococcosis was inversely correlated with the annual average LST, and positively correlated with both the average elevation and the prevalence rate of domestic animals. The prevalence of human alveolar echinococcosis was positively correlated with both NDVI in autumn and average elevation, and negatively correlated with NDVI in winter. CONCLUSION: The prevalence of echinococcosis in the population is affected by environmental factors. Environmental risk assessment and prediction can be conducted in order to rationally allocate health resources and improve both prevention and control efficiency of echinococcosis.


Assuntos
Equinococose , China/epidemiologia , Humanos , Equinococose/epidemiologia , Fatores de Risco , Animais , Prevalência , Cães , Meio Ambiente , Análise de Regressão
9.
Heliyon ; 10(15): e35016, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39157382

RESUMO

Objective: Delays in the diagnosis and treatment of pulmonary tuberculosis (PTB) can increase the risk of transmission, thereby posing a significant risk to public health. Early diagnosis is considered to play a crucial role in eliminating TB. Rapid testing, active case finding, and health education are effective strategies for reducing tuberculosis diagnosis delays (TDDs). This study aimed to quantitatively compare the impact of reducing the TDD on incidence rates among student and non-student groups, thus exploring the efficacy of shortening the TDD for ending the TB epidemic and providing a reference for achieving the target incidence rate for ending TB. Methods: We used unsupervised hierarchical clustering analysis and non-parametric tests to characterize the epidemiological characteristics of TDD. Additionally, a dynamic transmission model was used to quantify the impact of shortening the TDD on the incidence rates of TB among the two groups. Results: There was an initial increase in the TDD, followed by a decrease. Longer TDDs were observed in the northeastern region of China. Farmers, middle and high school students, middle-aged, elderly individuals and males exhibited relatively longer TDDs. A significant reduction in the incidence rate of PTB was observed when the TDD was decreased by 50 %. However, only reducing the TDD among non-students could achieve the goal of ending TB (i.e., achieving a minimum reduction of 63.00 %). Conclusions: TDD remains a serious risk to public health, and non-students were shown to experience longer TDD. Shortening the TDD is crucial for reducing the incidence rates of TB, especially among non-students. It is essential to develop a highly sensitive and effective system for eliminating TB among non-students.

10.
Sci Rep ; 14(1): 20472, 2024 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-39227742

RESUMO

This study examines tuberculosis (TB) incidence among students in Jilin Province, China, focusing on spatial, temporal, and demographic dynamics in areas of social inequality. Variation in incidence rate of TB was analyzed using the joinpoint regression method. Spatial analyses techniques included the global and local Moran indices and Getis-Ord Gi* analysis. Demographic changes in new cases were analyzed descriptively, and the Geodetector method measured the influence of risk factors on student TB incidence. The analysis revealed a declining trend in TB cases, particularly among male students. TB incidence showed geographical heterogeneity, with lower rates in underdeveloped rural areas compared to urban regions. Significant spatial correlations were observed, with high-high clusters forming in central Jilin Province. Hotspots of student TB transmission were primarily concentrated in the southwestern and central regions from 2008 to 2018. Socio-economic factors exhibited nonlinear enhancement effects on incidence rates, with a dominant bifactor effect. High-risk zones were predominantly located in urban centers, with university and high school students showing higher incidences than other educational stages. The study revealed economic determinants as being especially important in affecting TB incidence among students, with these factors having nonlinear interacting effects on student TB incidence.


Assuntos
Estudantes , Tuberculose , Humanos , China/epidemiologia , Masculino , Feminino , Incidência , Tuberculose/epidemiologia , Tuberculose/transmissão , Fatores de Risco , Adolescente , Fatores Socioeconômicos , Adulto Jovem , População Rural
11.
Pathogens ; 13(9)2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39338968

RESUMO

From 2011 to 2012, Northern Vietnam suffered its first large-scale hand, foot, and mouth disease (HFMD) epidemic. Two sets of official guidelines were issued during the outbreak to handle the HFMD crisis. The city of Hai Phong was used as a model to analyze the impact of the released guidelines. A total of 9621 HFMD cases were reported in Hai Phong city from April 2011 to December 2012. Three distinct waves of HFMD occurred. Enterovirus A71 and Coxsackievirus A16 were successively associated with the epidemics. Two periods, before and after the guidelines' release, could be distinguished and characterized by different patient patterns. The time to admission and severity changed notably. Guideline publications help the health system refocus on the 0.5-3 years age group with the highest incidence of the disease. The three waves showed different special distribution, but the main routes of infection were rivers and local secondary roads, most likely through local trade and occupational movements of people.

12.
Heliyon ; 10(11): e32164, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38868071

RESUMO

Introduction: Differences in transmissibility of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) in different districts are hard to assess. To address this, our study focused on calculating the Real-time reproduction number (R t ) for these variants in different regions. Methods: According to the criteria defined by the World Health Organization (WHO), the global landscape was categorized into six distinct regions. In each region, the predominant SARS-CoV-2 variant was first identified based on the proportion of variant sequencing analysis results. Then, using serial interval (SI) parameters, we calculated R t for the relevant Variant of Concern (VOC) in each region. This approach enabled us to compare the R t values of the same variant across different regions and analyze the transmissibility of each region's variant in relation to the overall situation in that region. Results: The progression of VOC for SARS-CoV-2 shows regional variations. However, a common sequence of evolution is observed: Wild-type → Alpha → Beta → Delta → Omicron. Moreover, an increasing trend is discerned within diverse regions where the shift in R t of distinct VOC corresponds with the overarching R t route of SARS-CoV-2 in specific regions. Conclusion: As the COVID-19 pandemic advances, regional epidemiological trends are aligning, likely due to similar virus mutations and shared public health strategies, suggesting opportunities for standardized global responses.

13.
Viruses ; 16(8)2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39205191

RESUMO

An HFMD outbreak spread over the city of Hai Phòng from summer 2011 to autumn 2012. This epidemic was chosen because it was the very first HFMD epidemic in North Vietnam, eliminating thus interferences with previous outbreaks. This epidemic displayed three separate waves. A complete dataset was collected for more than 9500 patients during this period, which enabled us to analyze this epidemic at different scales. Access to the healthcare system was crucial during this period, which was possible due to a reorganization of the system in February-March 2012. An analysis at the commune level enabled us to track the epidemic along certain communication routes. The three-waves structure reveals a wide disparity at the district level. We developed a mathematical model showing high accuracy at the adjustment of data for both the total number of cases and for the number of cases per week. As a consequence, the model was able to accurately determine the dates of the beginning and end of each wave and to show that they overlapped. Using mathematical functions associated with this model, it was possible to calculate the probability for a patient to belong to a specific wave.


Assuntos
Surtos de Doenças , Doença de Mão, Pé e Boca , Doença de Mão, Pé e Boca/epidemiologia , Doença de Mão, Pé e Boca/virologia , Humanos , Vietnã/epidemiologia , Modelos Teóricos , Epidemias , Pré-Escolar , Modelos Epidemiológicos
14.
China CDC Wkly ; 5(20): 437-441, 2023 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-37274767

RESUMO

What is already known about this topic?: In China, patients with echinococcosis receive complimentary healthcare services, such as medical treatment, diagnostic examinations, and follow-up care. Despite this, no studies have been conducted to assess the quality of patient management to date. What is added by this report?: This study reviewed the medical records of 899 patients who underwent albendazole treatment across 10 endemic counties. Out of 634 evaluable patient files, the proportion of patients with a ratio of actual follow-up and reexamination times to theoretical follow-up and reexamination times ≥0.8 were both low (21.92% and 23.19%, respectively). What are the implications for public health practices?: This study identified weaknesses and specific issues in patient management and proposed feasible recommendations to enhance patient file documentation, follow-up, and reexamination.

15.
R Soc Open Sci ; 10(5): 230288, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37266040

RESUMO

Wolbachia are endosymbiotic alpha-proteobacteria infecting a wide range of arthropods and nematode hosts with diverse interactions, from reproductive parasites to obligate mutualists. Their taxonomy is defined by lineages called supergroups (labelled by letters of the alphabet), while their evolutionary history is complex, with multiple horizontal transfers and secondary losses. One of the least recently derived, supergroup E, infects springtails (Collembola), widely distributed hexapods, with sexual and/or parthenogenetic populations depending on species. To better characterize the diversity of Wolbachia infecting springtails, the presence of Wolbachia was screened in 58 species. Eleven (20%) species were found to be positive, with three Wolbachia genotypes identified for the first time in supergroup A. The novel genotypes infect springtails ecologically and biologically different from those infected by supergroup E. To root the Wolbachia phylogeny, rather than distant other Rickettsiales, supergroup L infecting plant-parasitic nematodes was used here. We hypothesize that the ancestor of Wolbachia was consumed by soil-dwelling nematodes, and was transferred horizontally via plants into aphids, which then infected edaphic arthropods (e.g. springtails and oribatid mites) before expanding into most clades of terrestrial arthropods and filarial nematodes.

16.
Front Cell Infect Microbiol ; 13: 1212473, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37637464

RESUMO

Background: Severe acute respiratory syndrome (SARS) is a form of atypical pneumonia which took hundreds of lives when it swept the world two decades ago. The pathogen of SARS was identified as SARS-coronavirus (SARS-CoV) and it was mainly transmitted in China during the SARS epidemic in 2002-2003. SARS-CoV and SARS-CoV-2 have emerged from the SARS metapopulation of viruses. However, they gave rise to two different disease dynamics, a limited epidemic, and an uncontrolled pandemic, respectively. The characteristics of its spread in China are particularly noteworthy. In this paper, the unique characteristics of time, space, population distribution and transmissibility of SARS for the epidemic were discussed in detail. Methods: We adopted sliding average method to process the number of reported cases per day. An SEIAR transmission dynamics model, which was the first to take asymptomatic group into consideration and applied indicators of R 0, Reff, Rt to evaluate the transmissibility of SARS, and further illustrated the control effectiveness of interventions for SARS in 8 Chinese cities. Results: The R 0 for SARS in descending order was: Tianjin city (R 0 = 8.249), Inner Mongolia Autonomous Region, Shanxi Province, Hebei Province, Beijing City, Guangdong Province, Taiwan Province, and Hong Kong. R 0 of the SARS epidemic was generally higher in Mainland China than in Hong Kong and Taiwan Province (Mainland China: R 0 = 6.058 ± 1.703, Hong Kong: R 0 = 2.159, Taiwan: R 0 = 3.223). All cities included in this study controlled the epidemic successfully (Reff<1) with differences in duration. Rt in all regions showed a downward trend, but there were significant fluctuations in Guangdong Province, Hong Kong and Taiwan Province compared to other areas. Conclusion: The SARS epidemic in China showed a trend of spreading from south to north, i.e., Guangdong Province and Beijing City being the central regions, respectively, and from there to the surrounding areas. In contrast, the SARS epidemic in the central region did not stir a large-scale transmission. There were also significant differences in transmissibility among eight regions, with R0 significantly higher in the northern region than that in the southern region. Different regions were able to control the outbreak successfully in differences time.


Assuntos
COVID-19 , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave , Humanos , SARS-CoV-2 , COVID-19/epidemiologia , China/epidemiologia , Hong Kong/epidemiologia
17.
PNAS Nexus ; 1(4): pgac185, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36714875

RESUMO

The acquisition of new hosts is a fundamental mechanism by which parasitic organisms expand their host range and perpetuate themselves on an evolutionary scale. Among pathogens, viruses, due to their speed of evolution, are particularly efficient in producing new emergence events. However, even though these phenomena are particularly important to the human species and therefore specifically studied, the processes of virus emergence in a new host species are very complex and difficult to comprehend in their entirety. In order to provide a structured framework for understanding emergence in a species (including humans), a comprehensive qualitative model is an indispensable cornerstone. This model explicitly describes all the stages necessary for a virus circulating in the wild to come to the crossing of the epidemic threshold. We have therefore developed a complete descriptive model explaining all the steps necessary for a virus circulating in host populations to emerge in a new species. This description of the parameters presiding over the emergence of a new virus allows us to understand their nature and importance in the emergence process.

18.
Med Sci (Paris) ; 38(6-7): 600-607, 2022.
Artigo em Francês | MEDLINE | ID: mdl-35766859

RESUMO

Since the beginning of the COVID-19 pandemic, the question of the origin of this virus has been the subject of a vivid controversy. It is the question of the "origin" itself which is biased. Darwin showed that there is no determined origin to any animal or plant species, simply an evolutionary and selective process. The same is true for viruses, there is no origin, but an evolutionary process. Viruses circulate from host to host, animals or humans. Pandemic viruses are already circulating in humans and evolving before the onset of disease. This evolutionary process then continues and gives rise to successive variants. The solution is not to target the disease or the putative causative agent but rather to address the process of disease emergence.


Title: Le virus SARS-CoV-2 n'a pas « d'origine ¼. Abstract: Depuis le début de la pandémie de COVID-19, la question de l'origine de ce virus fait l'objet d'une vive polémique. C'est la question de « l'origine ¼ qui est biaisée. Darwin a montré qu'il n'y a pas d'origine déterminée à aucune espèce animale ou végétale, simplement un processus évolutif et sélectif. Il en est de même pour les virus, il n'y a pas d'origine, mais un processus évolutif. Les virus circulent d'hôte à hôte, animaux ou humains. Les virus pandémiques circulent déjà chez l'homme et évoluent avant l'apparition d'une maladie. Ce processus évolutif se poursuit et donne naissance à des variants successifs. La solution n'est pas de cibler la maladie ou le possible agent causal, mais plutôt de cibler le processus d'émergence de la maladie lui-même.


Assuntos
COVID-19 , SARS-CoV-2 , Animais , Humanos , Pandemias
19.
One Health ; 15: 100429, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36060458

RESUMO

SARS-CoV-2, the virus responsible for COVID-19 in humans, can efficiently infect a large number of animal species. Like any virus, and particularly RNA viruses, SARS-CoV-2 undergoes mutations during its life cycle some of which bring a selective advantage, leading to the selection of a given lineage. Minks are very susceptible to SARS-CoV-2 and owing to their presence in mass rearing, they make a good model for studying the relative importance of mutations in viral adaptation to host species. Variants, such as the mink-selected SARS-CoV-2 Y453F and D614G or H69del/V70del, Y453F, I692V and M1229I were identified in humans after spreading through densely caged minks. However, not all mink-specific mutations are conserved when the virus infects human populations back. Many questions remain regarding the interspecies evolution of SARS-CoV-2 and the dynamics of transmission leading to the emergence of new variant strains. We compared the human and mink ACE2 receptor structures and their interactions with SARS-CVoV-2 variants. In minks, ACE2 presents a Y34 amino acid instead of the H34 amino acid found in the human ACE2. H34 is essential for the interaction with the Y453 residue of the SARS-CoV-2 Spike protein. The Y453F mink mutation abolishes this conflict. A series of 18 mutations not involved in the direct ACE2 interaction was observed in addition to the Y453F and D614G in 16 different SARS-CoV-2 strains following bidirectional infections between humans and minks. These mutations were not random and were distributed into five different functional groups having an effect on the kinetics of ACE2-RD interaction. The interspecies transmission of SARS-CoV-2 from humans to minks and back to humans, generated specific mutations in each species which improved the affinity for the ACE2 receptor either by direct mutation of the core 453 residue or by associated compensatory mutations.

20.
Infect Dis Poverty ; 11(1): 10, 2022 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-35063031

RESUMO

BACKGROUND: Echinococcosis, a zoonotic parasitic disease, is caused by larval stages of cestodes in the Echinococcus genus. Echinococcosis is highly prevalent in ten provinces/autonomous regions of western and northern China. In 2016, an epidemiological survey of Tibet Autonomous Region (TAR) revealed that the prevalence of human echinococcosis was 1.66%, which was much higher than the average prevalence in China (0.24%). Therefore, to improve on the current prevention and control measures, it is important to understand the prevalence and spatial distribution characteristics of human echinococcosis at the township level in TAR. METHODS: Data for echinococcosis cases in 2018 were obtained from the annual report system of echinococcosis of Tibet Center for Disease Control and Prevention. Diagnosis had been performed via B-ultrasonography. The epidemic status of echinococcosis in all townships in TAR was classified according to the relevant standards of population prevalence indices as defined in the national technical plan for echinococcosis control. Spatial scan statistics were performed to establish the geographical townships that were most at risk of echinococcosis. RESULTS: In 2018, a total of 16,009 echinococcosis cases, whose prevalence was 0.53%, were recorded in 74 endemic counties in TAR. Based on the order of the epidemic degree, all the 692 townships were classified from high to low degrees. Among them, 127 townships had prevalence rates ≥ 1%. The high prevalence of human echinococcosis in TAR, which is associated with a wide geographic distribution, is a medical concern. Approximately 94.65% of the villages and towns reported echinococcosis cases. According to spatial distribution analysis, the prevalence of human echinococcosis was found to be clustered, with the specific clustering areas being identified. The cystic echinococcosis primary cluster covered 88 townships, while that of alveolar echinococcosis's covered 38 townships. CONCLUSIONS: This study shows spatial distributions of echinococcosis with different epidemic degrees in 692 townships of TAR and high-risk cluster areas at the township level. Our findings indicate that strengthening the echinococcosis prevention and control strategies in TAR should directed at townships with a high prevalence and high-risk clustering areas.


Assuntos
Equinococose , Echinococcus , Animais , China , Equinococose/epidemiologia , Humanos , Prevalência , Tibet/epidemiologia , Zoonoses
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