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1.
Proc Natl Acad Sci U S A ; 118(15)2021 04 13.
Artículo en Inglés | MEDLINE | ID: mdl-33822740

RESUMEN

The death toll and economic loss resulting from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic are stark reminders that we are vulnerable to zoonotic viral threats. Strategies are needed to identify and characterize animal viruses that pose the greatest risk of spillover and spread in humans and inform public health interventions. Using expert opinion and scientific evidence, we identified host, viral, and environmental risk factors contributing to zoonotic virus spillover and spread in humans. We then developed a risk ranking framework and interactive web tool, SpillOver, that estimates a risk score for wildlife-origin viruses, creating a comparative risk assessment of viruses with uncharacterized zoonotic spillover potential alongside those already known to be zoonotic. Using data from testing 509,721 samples from 74,635 animals as part of a virus discovery project and public records of virus detections around the world, we ranked the spillover potential of 887 wildlife viruses. Validating the risk assessment, the top 12 were known zoonotic viruses, including SARS-CoV-2. Several newly detected wildlife viruses ranked higher than known zoonotic viruses. Using a scientifically informed process, we capitalized on the recent wealth of virus discovery data to systematically identify and prioritize targets for investigation. The publicly accessible SpillOver platform can be used by policy makers and health scientists to inform research and public health interventions for prevention and rapid control of disease outbreaks. SpillOver is a living, interactive database that can be refined over time to continue to improve the quality and public availability of information on viral threats to human health.


Asunto(s)
Enfermedades Transmisibles Emergentes , Pandemias , Zoonosis , Animales , /transmisión , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/transmisión , Humanos , Zoonosis/epidemiología , Zoonosis/transmisión
2.
Arch Virol ; 166(5): 1455-1462, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33704558

RESUMEN

During the dengue epidemic in Yunnan Province, China, during 2019, a concurrent outbreak of chikungunya occurred in the city of Ruili, which is located in the southwest of the province, adjacent to Myanmar. As part of this outbreak, three neonatal cases of infection with indigenous chikungunya virus from mother-to-child (vertical) transmission were observed. Isolates of chikungunya virus were obtained from 37 serum samples of patients with chikungunya during this outbreak, and a phylogenetic analysis of these isolates revealed that they belong to the Indian Ocean subclade of the East/Central/South African genotype. The E1 genes of these viruses did not harbor the A226V mutation.


Asunto(s)
Fiebre Chikungunya/virología , Virus Chikungunya/aislamiento & purificación , Enfermedades Transmisibles Emergentes/virología , Transmisión Vertical de Enfermedad Infecciosa , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/transmisión , Virus Chikungunya/clasificación , Virus Chikungunya/genética , China/epidemiología , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/transmisión , Brotes de Enfermedades , Femenino , Genoma Viral/genética , Genotipo , Humanos , Masculino , Mutación , Filogenia , ARN Viral/genética , Proteínas Virales/genética
3.
J Med Microbiol ; 70(3)2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33599604

RESUMEN

Over a decade ago, a multidrug-resistant nosocomial fungus Candida auris emerged worldwide and has since become a significant challenge for clinicians and microbiologists across the globe. A resilient pathogen, C. auris survives harsh disinfectants, desiccation and high-saline environments. It readily colonizes the inanimate environment, susceptible patients and causes invasive infections that exact a high toll. Prone to misidentification by conventional microbiology techniques, C. auris rapidly acquires multiple genetic determinants that confer multidrug resistance. Whole-genome sequencing has identified four distinct clades of C. auris, and possibly a fifth one, in circulation. Even as our understanding of this formidable pathogen grows, the nearly simultaneous emergence of its distinct clades in different parts of the world, followed by their rapid global spread, remains largely unexplained. We contend that certain host-pathogen-environmental factors have been evolving along adverse trajectories for the last few decades, especially in regions where C. auris originally appeared, until these factors possibly reached a tipping point to compel the evolution, emergence and spread of C. auris. Comparative genomics has helped identify several resistance mechanisms in C. auris that are analogous to those seen in other Candida species, but they fail to fully explain how high-level resistance rapidly develops in this yeast. A better understanding of these unresolved aspects is essential not only for the effective management of C. auris patients, hospital outbreaks and its global spread but also for forecasting and tackling novel resistant pathogens that might emerge in the future. In this review, we discuss the emergence, spread and resistance of C. auris, and propose future investigations to tackle this resilient pathogen.


Asunto(s)
Candida/fisiología , Candidiasis/microbiología , Enfermedades Transmisibles Emergentes/microbiología , Farmacorresistencia Fúngica Múltiple , Microbiología Ambiental , Antiinfecciosos/farmacología , Antiinfecciosos/uso terapéutico , Candida/clasificación , Candida/aislamiento & purificación , Candida/patogenicidad , Candidiasis/epidemiología , Candidiasis/transmisión , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/transmisión , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Infección Hospitalaria/transmisión , Salud Global , Humanos , Virulencia
4.
Cell Host Microbe ; 29(2): 160-164, 2021 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-33539765

RESUMEN

The emergence of alternate variants of SARS-CoV-2 due to ongoing adaptations in humans and following human-to-animal transmission has raised concern over the efficacy of vaccines against new variants. We describe human-to-animal transmission (zooanthroponosis) of SARS-CoV-2 and its implications for faunal virus persistence and vaccine-mediated immunity.


Asunto(s)
/veterinaria , Enfermedades Transmisibles Emergentes/veterinaria , Zoonosis/transmisión , Zoonosis/virología , Animales , /transmisión , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/virología , Reservorios de Enfermedades/veterinaria , Reservorios de Enfermedades/virología , Humanos , Inmunidad , Vacunas Virales/inmunología
5.
Trends Parasitol ; 37(3): 181-184, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33454218

RESUMEN

The illegal wildlife trade (IWT) is a criminal practice bringing several ecological and public health consequences, such as the spreading of zoonotic pathogens and/or the introduction of exotic species of animals into new geographical areas. Here, we discuss potential risks of IWT on the spreading and emergence of zoonotic pathogens.


Asunto(s)
Animales Exóticos , Animales Salvajes , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles/transmisión , Zoonosis/transmisión , Animales , Comercio/ética , Comercio/legislación & jurisprudencia , Humanos
6.
Nat Commun ; 12(1): 151, 2021 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-33420058

RESUMEN

Mosquito-borne viruses threaten the Caribbean due to the region's tropical climate and seasonal reception of international tourists. Outbreaks of chikungunya and Zika have demonstrated the rapidity with which these viruses can spread. Concurrently, dengue fever cases have climbed over the past decade. Sustainable disease control measures are urgently needed to quell virus transmission and prevent future outbreaks. Here, to improve upon current control methods, we analyze temporal and spatial patterns of chikungunya, Zika, and dengue outbreaks reported in the Dominican Republic between 2012 and 2018. The viruses that cause these outbreaks are transmitted by Aedes mosquitoes, which are sensitive to seasonal climatological variability. We evaluate whether climate and the spatio-temporal dynamics of dengue outbreaks could explain patterns of emerging disease outbreaks. We find that emerging disease outbreaks were robust to the climatological and spatio-temporal constraints defining seasonal dengue outbreak dynamics, indicating that constant surveillance is required to prevent future health crises.


Asunto(s)
Fiebre Chikungunya/epidemiología , Enfermedades Transmisibles Emergentes/epidemiología , Dengue/epidemiología , Brotes de Enfermedades/estadística & datos numéricos , Enfermedades Endémicas/estadística & datos numéricos , Infección por el Virus Zika/epidemiología , Adolescente , Aedes/virología , Animales , Fiebre Chikungunya/prevención & control , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Virus Chikungunya/aislamiento & purificación , Niño , Preescolar , Enfermedades Transmisibles Emergentes/prevención & control , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/virología , Dengue/prevención & control , Dengue/transmisión , Dengue/virología , Virus del Dengue/aislamiento & purificación , Brotes de Enfermedades/prevención & control , República Dominicana/epidemiología , Enfermedades Endémicas/prevención & control , Monitoreo Epidemiológico , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Control de Mosquitos , Mosquitos Vectores/virología , Análisis Espacio-Temporal , Adulto Joven , Virus Zika/aislamiento & purificación , Infección por el Virus Zika/prevención & control , Infección por el Virus Zika/transmisión , Infección por el Virus Zika/virología
7.
Front Public Health ; 8: 596944, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33324602

RESUMEN

The World Health Organization defines a zoonosis as any infection naturally transmissible from vertebrate animals to humans. The pandemic of Coronavirus disease (COVID-19) caused by SARS-CoV-2 has been classified as a zoonotic disease, however, no animal reservoir has yet been found, so this classification is premature. We propose that COVID-19 should instead be classified an "emerging infectious disease (EID) of probable animal origin." To explore if COVID-19 infection fits our proposed re-categorization vs. the contemporary definitions of zoonoses, we reviewed current evidence of infection origin and transmission routes of SARS-CoV-2 virus and described this in the context of known zoonoses, EIDs and "spill-over" events. Although the initial one hundred COVID-19 patients were presumably exposed to the virus at a seafood Market in China, and despite the fact that 33 of 585 swab samples collected from surfaces and cages in the market tested positive for SARS-CoV-2, no virus was isolated directly from animals and no animal reservoir was detected. Elsewhere, SARS-CoV-2 has been detected in animals including domesticated cats, dogs, and ferrets, as well as captive-managed mink, lions, tigers, deer, and mice confirming zooanthroponosis. Other than circumstantial evidence of zoonotic cases in mink farms in the Netherlands, no cases of natural transmission from wild or domesticated animals have been confirmed. More than 40 million human COVID-19 infections reported appear to be exclusively through human-human transmission. SARS-CoV-2 virus and COVID-19 do not meet the WHO definition of zoonoses. We suggest SARS-CoV-2 should be re-classified as an EID of probable animal origin.


Asunto(s)
/clasificación , Enfermedades Transmisibles Emergentes , Zoonosis , Animales , Animales Salvajes , China , Enfermedades Transmisibles Emergentes/clasificación , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/virología , Humanos , Organización Mundial de la Salud , Zoonosis/clasificación , Zoonosis/transmisión , Zoonosis/virología
8.
Viruses ; 13(1)2020 12 27.
Artículo en Inglés | MEDLINE | ID: mdl-33375455

RESUMEN

The emergence of arthropod-borne viruses (arboviruses) as linked to land-use changes, especially the growing agricultural intensification and expansion efforts in rural parts of Africa, is of growing health concern. This places an additional burden on health systems as drugs, vaccines, and effective vector-control measures against arboviruses and their vectors remain lacking. An integrated One Health approach holds potential in the control and prevention of arboviruses. Land-use changes favour invasion by invasive alien plants (IAPs) and investigating their impact on mosquito populations may offer a new dimension to our understanding of arbovirus emergence. Of prime importance to understand is how IAPs influence mosquito life-history traits and how this may affect transmission of arboviruses to mammalian hosts, questions that we are exploring in this review. Potential effects of IAPs may be significant, including supporting the proliferation of immature and adult stages of mosquito vectors, providing additional nutrition and suitable microhabitats, and a possible interaction between ingested secondary plant metabolites and arboviruses. We conclude that aspects of vector biology are differentially affected by individual IAPs and that while some plants may have the potential to indirectly increase the risk of transmission of certain arboviruses by their direct interaction with the vectors, the reverse holds for other IAPs. In addition, we highlight priority research areas to improve our understanding of the potential health impacts of IAPs.


Asunto(s)
Infecciones por Arbovirus/epidemiología , Infecciones por Arbovirus/transmisión , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/transmisión , Culicidae/virología , Especies Introducidas , Mosquitos Vectores/virología , Plantas , Animales , Infecciones por Arbovirus/virología , Enfermedades Transmisibles Emergentes/virología , Ecosistema , Humanos
11.
Infect Dis Poverty ; 9(1): 140, 2020 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-33028426

RESUMEN

Most human pathogens originate from non-human hosts and certain pathogens persist in animal reservoirs. The transmission of such pathogens to humans may lead to self-sustaining chains of transmission. These pathogens represent the highest risk for future pandemics. For their prevention, the transmission over the species barrier - although rare - should, by all means, be avoided. In the current COVID-19 pandemic, surprisingly though, most of the current research concentrates on the control by drugs and vaccines, while comparatively little scientific inquiry focuses on future prevention. Already in 2012, the World Bank recommended to engage in a systemic One Health approach for zoonoses control, considering integrated surveillance-response and control of human and animal diseases for primarily economic reasons. First examples, like integrated West Nile virus surveillance in mosquitos, wild birds, horses and humans in Italy show evidence of financial savings from a closer cooperation of human and animal health sectors. Provided a zoonotic origin can be ascertained for the COVID-19 pandemic, integrated wildlife, domestic animal and humans disease surveillance-response may contribute to prevent future outbreaks. In conclusion, the earlier a zoonotic pathogen can be detected in the environment, in wildlife or in domestic animals; and the better human, animal and environmental surveillance communicate with each other to prevent an outbreak, the lower are the cumulative costs.


Asunto(s)
Enfermedades Transmisibles Emergentes/prevención & control , Pandemias/prevención & control , Zoonosis/prevención & control , Enfermedades de los Animales/epidemiología , Enfermedades de los Animales/prevención & control , Enfermedades de los Animales/transmisión , Animales , Betacoronavirus , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/transmisión , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/prevención & control , Infecciones por Coronavirus/transmisión , Reservorios de Enfermedades/veterinaria , Reservorios de Enfermedades/virología , Monitoreo Epidemiológico/veterinaria , Humanos , Italia/epidemiología , Salud Única , Pandemias/economía , Neumonía Viral/epidemiología , Neumonía Viral/prevención & control , Neumonía Viral/transmisión , Zoonosis/epidemiología , Zoonosis/transmisión
12.
Rev Esp Salud Publica ; 942020 Sep 30.
Artículo en Español | MEDLINE | ID: mdl-32994390

RESUMEN

In the midst of the SARS-CoV-2 public-health pandemic emergency, it is important to understand its zoonotic origin and how an animal virus finally infects humans. Identifying the circumstances in which a virus jumps species boundaries to infect humans so productively is objective of this work and will help us to determine the epidemiology and pathogenisis of this agent. Nowadays, it is known that bats serve as reservoir hosts for virus progenitor, but determine the possibility of a potential intermediate host of SARS-CoV-2 is still a challenge. Scientific investigations stablish the natural selection theory as the most probable (natural selection in an animal host before zoonotic transfer or acquired mutations in humans following crossing species barrier). It is necessary to find out how SARS-CoV-2 emerged, its rapidly spreads within a community and the optimal context in which this virus binds to human receptor. One Health is a multisectoral, collaborative and transdisciplinary approach which allows a cooperative working between animal and human health that will help us to introduce some possible control measures that might reduce the spread of the virus; improving sanitary management, identifying new outbreaks and preventing future zoonotic and pandemic events.


Asunto(s)
Betacoronavirus , Quirópteros/virología , Enfermedades Transmisibles Emergentes/transmisión , Infecciones por Coronavirus/transmisión , Reservorios de Enfermedades/virología , Pandemias , Neumonía Viral/transmisión , Zoonosis/transmisión , Animales , Betacoronavirus/genética , Betacoronavirus/patogenicidad , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/virología , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/virología , Salud Global , Humanos , Neumonía Viral/epidemiología , Neumonía Viral/virología , Selección Genética , Zoonosis/epidemiología , Zoonosis/virología
13.
Proc Natl Acad Sci U S A ; 117(42): 26151-26157, 2020 10 20.
Artículo en Inglés | MEDLINE | ID: mdl-32989148

RESUMEN

Emerging evidence suggests a resurgence of COVID-19 in the coming years. It is thus critical to optimize emergency response planning from a broad, integrated perspective. We developed a mathematical model incorporating climate-driven variation in community transmissions and movement-modulated spatial diffusions of COVID-19 into various intervention scenarios. We find that an intensive 8-wk intervention targeting the reduction of local transmissibility and international travel is efficient and effective. Practically, we suggest a tiered implementation of this strategy where interventions are first implemented at locations in what we call the Global Intervention Hub, followed by timely interventions in secondary high-risk locations. We argue that thinking globally, categorizing locations in a hub-and-spoke intervention network, and acting locally, applying interventions at high-risk areas, is a functional strategy to avert the tremendous burden that would otherwise be placed on public health and society.


Asunto(s)
Control de Enfermedades Transmisibles/métodos , Enfermedades Transmisibles Emergentes/prevención & control , Infecciones por Coronavirus/prevención & control , Transmisión de Enfermedad Infecciosa/prevención & control , Salud Global/tendencias , Pandemias/prevención & control , Neumonía Viral/prevención & control , Betacoronavirus , Clima , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/transmisión , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/transmisión , Predicción , Humanos , Cooperación Internacional , Modelos Teóricos , Neumonía Viral/epidemiología , Neumonía Viral/transmisión , Viaje
14.
PLoS One ; 15(8): e0237780, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32845922

RESUMEN

Modeling the behavior of zoonotic pandemic threats is a key component of their control. Many emerging zoonoses, such as SARS, Nipah, and Hendra, mutated from their wild type while circulating in an intermediate host population, usually a domestic species, to become more transmissible among humans, and this transmission route will only become more likely as agriculture and trade intensifies around the world. Passage through an intermediate host enables many otherwise rare diseases to become better adapted to humans, and so understanding this process with accurate mathematical models is necessary to prevent epidemics of emerging zoonoses, guide policy interventions in public health, and predict the behavior of an epidemic. In this paper, we account for a zoonotic disease mutating in an intermediate host by introducing a new mathematical model for disease transmission among three species. We present a model of these disease dynamics, including the equilibria of the system and the basic reproductive number of the pathogen, finding that in the presence of biologically realistic interspecies transmission parameters, a zoonotic disease with the capacity to mutate in an intermediate host population can establish itself in humans even if its R0 in humans is less than 1. This result and model can be used to predict the behavior of any zoonosis with an intermediate host and assist efforts to protect public health.


Asunto(s)
Control de Enfermedades Transmisibles/métodos , Enfermedades Transmisibles Emergentes/epidemiología , Reservorios de Enfermedades/microbiología , Modelos Biológicos , Zoonosis/epidemiología , Animales , Animales Domésticos/microbiología , Animales Salvajes/microbiología , Bacterias/genética , Bacterias/patogenicidad , Enfermedades Transmisibles Emergentes/microbiología , Enfermedades Transmisibles Emergentes/prevención & control , Enfermedades Transmisibles Emergentes/transmisión , Brotes de Enfermedades/prevención & control , Vectores de Enfermedades , Especificidad del Huésped/genética , Humanos , Tasa de Mutación , Virus/genética , Virus/patogenicidad , Zoonosis/microbiología , Zoonosis/prevención & control , Zoonosis/transmisión
15.
Cell ; 182(5): 1077-1092, 2020 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-32846157

RESUMEN

Infectious diseases prevalent in humans and animals are caused by pathogens that once emerged from other animal hosts. In addition to these established infections, new infectious diseases periodically emerge. In extreme cases they may cause pandemics such as COVID-19; in other cases, dead-end infections or smaller epidemics result. Established diseases may also re-emerge, for example by extending geographically or by becoming more transmissible or more pathogenic. Disease emergence reflects dynamic balances and imbalances, within complex globally distributed ecosystems comprising humans, animals, pathogens, and the environment. Understanding these variables is a necessary step in controlling future devastating disease emergences.


Asunto(s)
Enfermedades Transmisibles Emergentes/epidemiología , Infecciones por Coronavirus/epidemiología , Neumonía Viral/epidemiología , Enfermedades Transmisibles Emergentes/prevención & control , Enfermedades Transmisibles Emergentes/transmisión , Infecciones por Coronavirus/prevención & control , Infecciones por Coronavirus/transmisión , Demografía , Ambiente , Interacciones Huésped-Patógeno , Humanos , Pandemias/prevención & control , Neumonía Viral/prevención & control , Neumonía Viral/transmisión
16.
Proc Natl Acad Sci U S A ; 117(36): 22597-22602, 2020 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-32826332

RESUMEN

By March 2020, COVID-19 led to thousands of deaths and disrupted economic activity worldwide. As a result of narrow case definitions and limited capacity for testing, the number of unobserved severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections during its initial invasion of the United States remains unknown. We developed an approach for estimating the number of unobserved infections based on data that are commonly available shortly after the emergence of a new infectious disease. The logic of our approach is, in essence, that there are bounds on the amount of exponential growth of new infections that can occur during the first few weeks after imported cases start appearing. Applying that logic to data on imported cases and local deaths in the United States through 12 March, we estimated that 108,689 (95% posterior predictive interval [95% PPI]: 1,023 to 14,182,310) infections occurred in the United States by this date. By comparing the model's predictions of symptomatic infections with local cases reported over time, we obtained daily estimates of the proportion of symptomatic infections detected by surveillance. This revealed that detection of symptomatic infections decreased throughout February as exponential growth of infections outpaced increases in testing. Between 24 February and 12 March, we estimated an increase in detection of symptomatic infections, which was strongly correlated (median: 0.98; 95% PPI: 0.66 to 0.98) with increases in testing. These results suggest that testing was a major limiting factor in assessing the extent of SARS-CoV-2 transmission during its initial invasion of the United States.


Asunto(s)
Enfermedades Transmisibles Emergentes/transmisión , Infecciones por Coronavirus/transmisión , Modelos Teóricos , Neumonía Viral/transmisión , Betacoronavirus/aislamiento & purificación , Técnicas de Laboratorio Clínico , Enfermedades Transmisibles Emergentes/diagnóstico , Enfermedades Transmisibles Emergentes/epidemiología , Infecciones Comunitarias Adquiridas , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/epidemiología , Humanos , Pandemias , Neumonía Viral/diagnóstico , Neumonía Viral/epidemiología , Vigilancia en Salud Pública , Estados Unidos/epidemiología
17.
PLoS Negl Trop Dis ; 14(8): e0008338, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32790670

RESUMEN

Pathogens originating from wildlife (zoonoses) pose a significant public health burden, comprising the majority of emerging infectious diseases. Efforts to control and prevent zoonotic disease have traditionally focused on animal-to-human transmission, or "spillover." However, in the modern era, increasing international mobility and commerce facilitate the spread of infected humans, nonhuman animals (hereafter animals), and their products worldwide, thereby increasing the risk that zoonoses will be introduced to new geographic areas. Imported zoonoses can potentially "spill back" to infect local wildlife-a danger magnified by urbanization and other anthropogenic pressures that increase contacts between human and wildlife populations. In this way, humans can function as vectors, dispersing zoonoses from their ancestral enzootic systems to establish reservoirs elsewhere in novel animal host populations. Once established, these enzootic cycles are largely unassailable by standard control measures and have the potential to feed human epidemics. Understanding when and why translocated zoonoses establish novel enzootic cycles requires disentangling ecologically complex and stochastic interactions between the zoonosis, the human population, and the natural ecosystem. In this Review, we address this challenge by delineating potential ecological mechanisms affecting each stage of enzootic establishment-wildlife exposure, enzootic infection, and persistence-applying existing ecological concepts from epidemiology, invasion biology, and population ecology. We ground our discussion in the neotropics, where four arthropod-borne viruses (arboviruses) of zoonotic origin-yellow fever, dengue, chikungunya, and Zika viruses-have separately been introduced into the human population. This paper is a step towards developing a framework for predicting and preventing novel enzootic cycles in the face of zoonotic translocations.


Asunto(s)
Infecciones por Arbovirus/epidemiología , Arbovirus , Zoonosis/epidemiología , Américas , Animales , Animales Salvajes/virología , Infecciones por Arbovirus/transmisión , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/transmisión , Enfermedades Transmisibles Emergentes/virología , Ecosistema , Humanos , Mosquitos Vectores , Clima Tropical , Zoonosis/transmisión , Zoonosis/virología
20.
Int J Infect Dis ; 99: 325-327, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32544669

RESUMEN

Few studies have focused on the transmission efficiency of asymptomatic carriers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Our follow-up study was performed on 147 asymptomatic carriers in Anhui Province. Of these, 50.0% were male, 50.3% were older than 40 years, 43.8% were farmers, and 68.7% were from the north of Anhui Province. 16 of the 147 asymptomatic carriers developed symptoms in the following 14 days of isolated observation, and were subsequently diagnosed as confirmed cases. The possible latent infection period was found to range from 1-5 days before onset, with a median time of 2 days. The second attack rate for the 16 confirmed cases who had transferred from being asymptomatic carriers was 9.7% (23/236 close contacts), while for the 131 asymptomatic carriers the rate was 2.6% (24/914 close contacts), showing a significant difference in second attack rate between the two groups (p<0.001). Our study indicated that COVID-19 cases are contagious during the incubation period, and that close contact screening should be extended to include the incubation period. Our results also showed that the transmission efficiency for asymptomatic carriers was lower than that for confirmed case.


Asunto(s)
Betacoronavirus/fisiología , Enfermedades Transmisibles Emergentes/transmisión , Infecciones por Coronavirus/transmisión , Pandemias/prevención & control , Neumonía Viral/transmisión , Adulto , Enfermedades Asintomáticas , China/epidemiología , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/prevención & control , Enfermedades Transmisibles Emergentes/virología , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/prevención & control , Infecciones por Coronavirus/virología , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Tamizaje Masivo , Persona de Mediana Edad , Neumonía Viral/epidemiología , Neumonía Viral/prevención & control , Neumonía Viral/virología , Adulto Joven
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