Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 150
Filtrar
1.
bioRxiv ; 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34790977

RESUMO

There remains an unmet need for globally deployable, low-cost therapeutics for the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Previously, we reported on the isolation and in vitro characterization of a potent single-domain nanobody, NIH-CoVnb-112, specific for the receptor binding domain (RBD) of SARS-CoV-2. Here, we report on the molecular basis for the observed broad in vitro neutralization capability of NIH-CoVnb-112 against variant SARS-CoV-2 pseudoviruses, including the currently dominant Delta variant. The structure of NIH-CoVnb-112 bound to SARS-CoV-2 RBD reveals a large contact surface area overlapping the angiotensin converting enzyme 2 (ACE2) binding site, which is largely unencumbered by the common RBD mutations. In an in vivo pilot study, we demonstrate effective reductions in weight loss, viral burden, and lung pathology in a Syrian hamster model of COVID-19 following nebulized delivery of NIH-CoVnb-112. These findings support the further development of NIH-CoVnb-112 as a potential adjunct preventative therapeutic for the treatment of SARS-CoV-2 infection.

2.
Emerg Microbes Infect ; 10(1): 2199-2201, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34749583

RESUMO

We report pilot studies to evaluate the susceptibility of common domestic livestock (cattle, sheep, goat, alpaca, rabbit, and horse) to intranasal infection with SARS-CoV-2. None of the infected animals shed infectious virus via nasal, oral, or faecal routes, although viral RNA was detected in several animals. Further, neutralizing antibody titres were low or non-existent one month following infection. These results suggest that domestic livestock are unlikely to contribute to SARS-CoV-2 epidemiology.

3.
Emerg Infect Dis ; 27(12): 3103-3110, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34808089

RESUMO

Anthrax is a disease of concern in many mammals, including humans. Management primarily consists of prevention through vaccination and tracking clinical-level observations because environmental isolation is laborious and bacterial distribution across large geographic areas difficult to confirm. Feral swine (Sus scrofa) are an invasive species with an extensive range in the southern United States that rarely succumbs to anthrax. We present evidence that feral swine might serve as biosentinels based on comparative seroprevalence in swine from historically defined anthrax-endemic and non-anthrax-endemic regions of Texas. Overall seropositivity was 43.7% (n = 478), and logistic regression revealed county endemicity status, age-class, sex, latitude, and longitude were informative for predicting antibody status. However, of these covariates, only latitude was statistically significant (ß = -0.153, p = 0.047). These results suggests anthrax exposure in swine, when paired with continuous location data, could serve as a proxy for bacterial presence in specific areas.

4.
NPJ Vaccines ; 6(1): 122, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34671047

RESUMO

Early in the SARS-CoV-2 pandemic concerns were raised regarding infection of new animal hosts and the effect on viral epidemiology. Infection of other animals could be detrimental by causing clinical disease, allowing further mutations, and bares the risk for the establishment of a non-human reservoir. Cats were the first reported animals susceptible to natural and experimental infection with SARS-CoV-2. Given the concerns these findings raised, and the close contact between humans and cats, we aimed to develop a vaccine candidate that could reduce SARS-CoV-2 infection and in addition to prevent spread among cats. Here we report that a Replicon Particle (RP) vaccine based on Venezuelan equine encephalitis virus, known to be safe and efficacious in a variety of animal species, could induce neutralizing antibody responses in guinea pigs and cats. The design of the SARS-CoV-2 spike immunogen was critical in developing a strong neutralizing antibody response. Vaccination of cats was able to induce high neutralizing antibody responses, effective also against the SARS-CoV-2 B.1.1.7 variant. Interestingly, in contrast to control animals, the infectious virus could not be detected in oropharyngeal or nasal swabs of vaccinated cats after SARS-CoV-2 challenge. Correspondingly, the challenged control cats spread the virus to in-contact cats whereas the vaccinated cats did not transmit the virus. The results show that the RP vaccine induces protective immunity preventing SARS-CoV-2 infection and transmission. These data suggest that this RP vaccine could be a multi-species vaccine useful to prevent infection and spread to and between animals should that approach be required.

5.
Proc Natl Acad Sci U S A ; 118(44)2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34716263

RESUMO

SARS-CoV-2 spillback from humans into domestic and wild animals has been well documented, and an accumulating number of studies illustrate that human-to-animal transmission is widespread in cats, mink, deer, and other species. Experimental inoculations of cats, mink, and ferrets have perpetuated transmission cycles. We sequenced full genomes of Vero cell-expanded SARS-CoV-2 inoculum and viruses recovered from cats (n = 6), dogs (n = 3), hamsters (n = 3), and a ferret (n = 1) following experimental exposure. Five nonsynonymous changes relative to the USA-WA1/2020 prototype strain were near fixation in the stock used for inoculation but had reverted to wild-type sequences at these sites in dogs, cats, and hamsters within 1- to 3-d postexposure. A total of 14 emergent variants (six in nonstructural genes, six in spike, and one each in orf8 and nucleocapsid) were detected in viruses recovered from animals. This included substitutions in spike residues H69, N501, and D614, which also vary in human lineages of concern. Even though a live virus was not cultured from dogs, substitutions in replicase genes were detected in amplified sequences. The rapid selection of SARS-CoV-2 variants in vitro and in vivo reveals residues with functional significance during host switching. These observations also illustrate the potential for spillback from animal hosts to accelerate the evolution of new viral lineages, findings of particular concern for dogs and cats living in households with COVID-19 patients. More generally, this glimpse into viral host switching reveals the unrealized rapidity and plasticity of viral evolution in experimental animal model systems.


Assuntos
COVID-19/virologia , Evolução Molecular , SARS-CoV-2/genética , Seleção Genética , Animais , COVID-19/veterinária , Gatos , Chlorocebus aethiops , Cães , Furões , Frequência do Gene , Animais de Estimação/virologia , SARS-CoV-2/patogenicidade , Células Vero , Proteínas Virais/genética
6.
Cell Rep ; 37(2): 109822, 2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34610292

RESUMO

Potent neutralizing monoclonal antibodies are one of the few agents currently available to treat COVID-19. SARS-CoV-2 variants of concern (VOCs) that carry multiple mutations in the viral spike protein can exhibit neutralization resistance, potentially affecting the effectiveness of some antibody-based therapeutics. Here, the generation of a diverse panel of 91 human, neutralizing monoclonal antibodies provides an in-depth structural and phenotypic definition of receptor binding domain (RBD) antigenic sites on the viral spike. These RBD antibodies ameliorate SARS-CoV-2 infection in mice and hamster models in a dose-dependent manner and in proportion to in vitro, neutralizing potency. Assessing the effect of mutations in the spike protein on antibody recognition and neutralization highlights both potent single antibodies and stereotypic classes of antibodies that are unaffected by currently circulating VOCs, such as B.1.351 and P.1. These neutralizing monoclonal antibodies and others that bind analogous epitopes represent potentially useful future anti-SARS-CoV-2 therapeutics.


Assuntos
Enzima de Conversão de Angiotensina 2/imunologia , Anticorpos Neutralizantes/imunologia , SARS-CoV-2/imunologia , Enzima de Conversão de Angiotensina 2/metabolismo , Enzima de Conversão de Angiotensina 2/ultraestrutura , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Neutralizantes/ultraestrutura , Anticorpos Antivirais/imunologia , COVID-19/imunologia , Cricetinae , Microscopia Crioeletrônica/métodos , Epitopos/imunologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Testes de Neutralização , Ligação Proteica/fisiologia , Receptores Virais/metabolismo , SARS-CoV-2/patogenicidade , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia
7.
Vaccine ; 39(47): 6894-6901, 2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34696935

RESUMO

Coccidioidomycosis is a significant health problem of dogs and humans in endemic regions, especially California and Arizona in the U.S. Both species would greatly benefit from a vaccine to prevent this disease. A live avirulent vaccine candidate, Δcps1, was tested for tolerability and efficacy to prevent pulmonary coccidioidomycosis in a canine challenge model. Vaccine injection-site reactions were transient and there were no systemic effects observed. Six of seven vaccine sites tested and all draining lymph nodes were sterile post-vaccination. Following infection with Coccidioides posadasii, strain Silveira, arthroconidia into the lungs, dogs given primary and booster vaccinations had significantly reduced lung fungal burdens (P = 0.0003) and composite disease scores (P = 0.0002) compared to unvaccinated dogs. Dogs vaccinated once had fungal burdens intermediate between those given two doses or none, but disease scores were not significantly different from unvaccinated (P = 0.675). Δcps1 was well-tolerated in the dogs and it afforded a high level of protection when given as prime and boost. These results drive the Δcps1 vaccine toward a licensed veterinary vaccine and support continued development of this vaccine to prevent coccidioidomycosis in humans.

8.
Emerg Infect Dis ; 27(8): 2073-2080, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34286685

RESUMO

Wild animals have been implicated as the origin of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but it is largely unknown how the virus affects most wildlife species and if wildlife could ultimately serve as a reservoir for maintaining the virus outside the human population. We show that several common peridomestic species, including deer mice, bushy-tailed woodrats, and striped skunks, are susceptible to infection and can shed the virus in respiratory secretions. In contrast, we demonstrate that cottontail rabbits, fox squirrels, Wyoming ground squirrels, black-tailed prairie dogs, house mice, and racoons are not susceptible to SARS-CoV-2 infection. Our results expand the knowledge base of susceptible species and provide evidence that human-wildlife interactions could result in continued transmission of SARS-CoV-2.


Assuntos
COVID-19 , SARS-CoV-2 , Animais , Animais Selvagens , Suscetibilidade a Doenças , Humanos , Mamíferos , Camundongos
9.
PLoS One ; 16(5): e0251841, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34038460

RESUMO

Outbreaks of avian influenza virus (AIV) infection included the spread of highly pathogenic AIV in commercial poultry and backyard flocks in the spring of 2015. This resulted in estimated losses of more than $8.5 million from federal government expenditures, $1.6 billion from direct losses to produces arising from destroyed turkey and chicken egg production, and economy-wide indirect costs of $3.3 billion from impacts on retailers and the food service industries. Additionally, these outbreaks resulted in the death or depopulation of nearly 50 million domestic birds. Domesticated male ferrets (Mustela putorius furo) were trained to display a specific conditioned behavior (i.e. active scratch alert) in response to feces from AIV-infected mallards in comparison to feces from healthy ducks. In order to establish that ferrets were identifying samples based on odors associated with infection, additional experiments controlled for potentially confounding effects, such as: individual duck identity, housing and feed, inoculation concentration, and day of sample collection (post-infection). A final experiment revealed that trained ferrets could detect AIV infection status even in the presence of samples from mallards inoculated with Newcastle disease virus or infectious laryngotracheitis virus. These results indicate that mammalian biodetectors are capable of discriminating the specific odors emitted from the feces of non-infected versus AIV infected mallards, suggesting that the health status of waterfowl can be evaluated non-invasively for AIV infection via monitoring of volatile fecal metabolites. Furthermore, in situ monitoring using trained biodetectors may be an effective tool for assessing population health.


Assuntos
Patos/virologia , Furões/fisiologia , Influenza Aviária/diagnóstico , Odorantes/análise , Animais , Galinhas/virologia , Fezes/virologia , Humanos , Vírus da Influenza A/patogenicidade , Influenza Aviária/virologia , Aves Domésticas/virologia , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/virologia , Perus/virologia
10.
Vaccines (Basel) ; 9(4)2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33916180

RESUMO

The COVID-19 pandemic has generated intense interest in the rapid development and evaluation of vaccine candidates for this disease and other emerging diseases. Several novel methods for preparing vaccine candidates are currently undergoing clinical evaluation in response to the urgent need to prevent the spread of COVID-19. In many cases, these methods rely on new approaches for vaccine production and immune stimulation. We report on the use of a novel method (SolaVAX) for production of an inactivated vaccine candidate and the testing of that candidate in a hamster animal model for its ability to prevent infection upon challenge with SARS-CoV-2 virus. The studies employed in this work included an evaluation of the levels of neutralizing antibody produced post-vaccination, levels of specific antibody sub-types to RBD and spike protein that were generated, evaluation of viral shedding post-challenge, flow cytometric and single cell sequencing data on cellular fractions and histopathological evaluation of tissues post-challenge. The results from this preliminary evaluation provide insight into the immunological responses occurring as a result of vaccination with the proposed vaccine candidate and the impact that adjuvant formulations, specifically developed to promote Th1 type immune responses, have on vaccine efficacy and protection against infection following challenge with live SARS-CoV-2. This data may have utility in the development of effective vaccine candidates broadly. Furthermore, the results of this preliminary evaluation suggest that preparation of a whole virion vaccine for COVID-19 using this specific photochemical method may have potential utility in the preparation of one such vaccine candidate.

11.
NPJ Vaccines ; 6(1): 47, 2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33785745

RESUMO

To generate an inexpensive readily manufactured COVID-19 vaccine, we employed the LVS ΔcapB vector platform, previously used to generate potent candidate vaccines against Select Agent diseases tularemia, anthrax, plague, and melioidosis. Vaccines expressing SARS-CoV-2 structural proteins are constructed using the LVS ΔcapB vector, a highly attenuated replicating intracellular bacterium, and evaluated for efficacy in golden Syrian hamsters, which develop severe COVID-19-like disease. Hamsters immunized intradermally or intranasally with a vaccine co-expressing the Membrane and Nucleocapsid proteins and challenged 5 weeks later with a high dose of SARS-CoV-2 are protected against severe weight loss and lung pathology and show reduced viral loads in the oropharynx and lungs. Protection correlates with anti-Nucleocapsid antibody. This potent vaccine should be safe; inexpensive; easily manufactured, stored, and distributed; and given the high homology between Membrane and Nucleocapsid proteins of SARS-CoV and SARS-CoV-2, potentially serve as a universal vaccine against the SARS subset of pandemic causing ß-coronaviruses.

12.
J Wildl Dis ; 57(1): 51-59, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33635996

RESUMO

Eastern populations of Ruffed Grouse (Bonasa umbellus) have been in a decades-long decline across the mid-Atlantic and southern Appalachian Mountains of the US. West Nile virus (WNV), which first arrived in the US in 1999, is suspected to have contributed to these declines based on decreased population indices since the arrival of WNV in Pennsylvania as well as on high, experimentally induced WNV-associated morbidity rates. A 3-yr statewide survey was conducted across Pennsylvania to measure flavivirus (i.e., WNV) seroprevalence among hunter-harvested grouse. The overall seroprevalence from 2015-17 was 14.4% (81/563); annual seroprevalence ranged from 2.8% (4/145) in the 2017 hunt year to 22.6% (52/230) in 2016-17. We analyzed the effects of numerous variables (i.e., Ruffed Grouse age and sex, hunt year, WNV vector index [VI], and region of Pennsylvania) on WNV serostatus by logistic regression. While there was no significant difference in WNV seroprevalence between sex and age group, there was significant variation in seroprevalence between geographic regions of Pennsylvania and across hunt years. Additionally, there was a negative correlation between WNV seroprevalence and VI. Low seroprevalence rates among Ruffed Grouse corresponded to years with a high VI, supporting experimental findings that Ruffed Grouse may be highly susceptible to WNV-associated disease. Additional strategic research efforts are essential to more effectively measure the effects of WNV on Ruffed Grouse and other vulnerable avian species.


Assuntos
Doenças das Aves/virologia , Culicidae/virologia , Galliformes , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental , Animais , Animais Selvagens , Doenças das Aves/epidemiologia , Corvos/virologia , Feminino , Masculino , Mosquitos Vetores/virologia , Pennsylvania/epidemiologia , Dinâmica Populacional , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/epidemiologia
13.
Am J Trop Med Hyg ; 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33534764

RESUMO

Powassan virus (POWV) is a tick-borne virus maintained in sylvatic cycles between mammalian wildlife hosts and ticks (primarily Ixodes spp.). There are two currently recognized lineages, POWV-lineage 1 (POWV-L1) and deer tick virus (DTV; lineage 2), both of which can cause fatal neurologic disease in humans. Increased numbers of human case reports in the northeastern and north central United States in recent years have fueled questions into POWV epidemiology. We inoculated three candidate wildlife POWV reservoir hosts, groundhogs (Marmota monax), striped skunks (Mephitis mephitis), and fox squirrels (Sciurus niger), with either POWV-L1 or DTV. Resulting viremia, tissue tropism, and pathology were minimal in most inoculated individuals of all three species, with low (peak titer range, 101.7-103.3 plaque-forming units/mL serum) or undetectable viremia titers, lack of detection in tissues except for low titers in spleen, and seroconversion in most individuals by 21 days postinoculation (DPI). Pathology was limited and most commonly consisted of mild inflammation in the brain of POWV-L1- and DTV-inoculated skunks on four and 21 DPI, respectively. These results reveal variation in virulence and host competence among wild mammalian species, and a likely limited duration of host infectiousness to ticks during enzootic transmission cycles. However, POWV can transmit rapidly from tick to host, and tick co-feeding may be an additional transmission mechanism. The rare and low-level detections of viremia in these three, common, wild mammal species suggest that vector-host dynamics should continue to be explored, along with eco-epidemiological aspects of enzootic POWV transmission in different regions and virus lineages.

14.
J Exp Med ; 218(3)2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33211088

RESUMO

SARS-CoV-2, the causative agent of COVID-19, has been responsible for over 42 million infections and 1 million deaths since its emergence in December 2019. There are few therapeutic options and no approved vaccines. Here, we examine the properties of highly potent human monoclonal antibodies (hu-mAbs) in a Syrian hamster model of SARS-CoV-2 and in a mouse-adapted model of SARS-CoV-2 infection (SARS-CoV-2 MA). Antibody combinations were effective for prevention and in therapy when administered early. However, in vitro antibody neutralization potency did not uniformly correlate with in vivo protection, and some hu-mAbs were more protective in combination in vivo. Analysis of antibody Fc regions revealed that binding to activating Fc receptors contributes to optimal protection against SARS-CoV-2 MA. The data indicate that intact effector function can affect hu-mAb protective activity and that in vivo testing is required to establish optimal hu-mAb combinations for COVID-19 prevention.


Assuntos
Anticorpos Monoclonais Murinos , Anticorpos Neutralizantes , Anticorpos Antivirais , Betacoronavirus/imunologia , Infecções por Coronavirus , Pandemias , Pneumonia Viral , Animais , Anticorpos Monoclonais Murinos/imunologia , Anticorpos Monoclonais Murinos/farmacologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/farmacologia , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/farmacologia , COVID-19 , Linhagem Celular , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/terapia , Feminino , Humanos , Mesocricetus , Camundongos , Camundongos Endogâmicos BALB C , Pneumonia Viral/imunologia , Pneumonia Viral/terapia , SARS-CoV-2
15.
Viruses ; 12(12)2020 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-33266124

RESUMO

Within the past two decades, three zoonotic betacoronaviruses have been associated with outbreaks causing severe respiratory disease in humans. Of these, Middle East respiratory s yndrome coronavirus (MERS-CoV) is the only zoonotic coronavirus that is known to consistently result in frequent zoonotic spillover events from the proximate reservoir host-the dromedary camel. A comprehensive understanding of infection in dromedaries is critical to informing public health recommendations and implementing intervention strategies to mitigate spillover events. Experimental models of reservoir disease are absolutely critical in understanding the pathogenesis and transmission, and are key to testing potential dromedary vaccines against MERS-CoV. In this review, we describe experimental infections of dromedary camels as well as additional camelid models used to further understand the camel's role in MERS-CoV spillover to humans.


Assuntos
Camelus/virologia , Infecções por Coronavirus/transmissão , Infecções por Coronavirus/virologia , Reservatórios de Doenças/virologia , Coronavírus da Síndrome Respiratória do Oriente Médio/patogenicidade , Animais , Infecções por Coronavirus/patologia , Infecções por Coronavirus/prevenção & controle , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/fisiologia , Modelos Biológicos , Vacinação/veterinária , Eliminação de Partículas Virais , Zoonoses/prevenção & controle , Zoonoses/transmissão , Zoonoses/virologia
16.
Viruses ; 12(9)2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32911797

RESUMO

Maternal influenza A viral infections in humans are associated with low birth weight, increased risk of pre-term birth, stillbirth and congenital defects. To examine the effect of maternal influenza virus infection on placental and fetal growth, pregnant C57BL/6 mice were inoculated intranasally with influenza A virus A/CA/07/2009 pandemic H1N1 or phosphate-buffered saline (PBS) at E3.5, E7.5 or E12.5, and the placentae and fetuses collected and weighed at E18.5. Fetal thymuses were pooled from each litter. Placentae were examined histologically, stained by immunohistochemistry (IHC) for CD34 (hematopoietic progenitor cell antigen) and vascular channels quantified. RNA from E7.5 and E12.5 placentae and E7.5 fetal thymuses was subjected to RNA sequencing and pathway analysis. Placental weights were decreased in litters inoculated with influenza at E3.5 and E7.5. Placentae from E7.5 and E12.5 inoculated litters exhibited decreased labyrinth development and the transmembrane protein 150A gene was upregulated in E7.5 placentae. Fetal weights were decreased in litters inoculated at E7.5 and E12.5 compared to controls. RNA sequencing of E7.5 thymuses indicated that 957 genes were downregulated ≥2-fold including Mal, which is associated with Toll-like receptor signaling and T cell differentiation. There were 28 upregulated genes. It is concluded that maternal influenza A virus infection impairs fetal thymic gene expression as well as restricting placental and fetal growth.


Assuntos
Vírus da Influenza A Subtipo H1N1/fisiologia , Influenza Humana/genética , Influenza Humana/fisiopatologia , Placenta/metabolismo , Efeitos Tardios da Exposição Pré-Natal/genética , Timo/metabolismo , Transcriptoma , Animais , Feminino , Desenvolvimento Fetal , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Influenza Humana/embriologia , Influenza Humana/virologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Placenta/virologia , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Efeitos Tardios da Exposição Pré-Natal/virologia , Timo/embriologia
17.
Proc Natl Acad Sci U S A ; 117(42): 26382-26388, 2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-32994343

RESUMO

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reached nearly every country in the world with extraordinary person-to-person transmission. The most likely original source of the virus was spillover from an animal reservoir and subsequent adaptation to humans sometime during the winter of 2019 in Wuhan Province, China. Because of its genetic similarity to SARS-CoV-1, it is probable that this novel virus has a similar host range and receptor specificity. Due to concern for human-pet transmission, we investigated the susceptibility of domestic cats and dogs to infection and potential for infected cats to transmit to naive cats. We report that cats are highly susceptible to infection, with a prolonged period of oral and nasal viral shedding that is not accompanied by clinical signs, and are capable of direct contact transmission to other cats. These studies confirm that cats are susceptible to productive SARS-CoV-2 infection, but are unlikely to develop clinical disease. Further, we document that cats developed a robust neutralizing antibody response that prevented reinfection following a second viral challenge. Conversely, we found that dogs do not shed virus following infection but do seroconvert and mount an antiviral neutralizing antibody response. There is currently no evidence that cats or dogs play a significant role in human infection; however, reverse zoonosis is possible if infected owners expose their domestic pets to the virus during acute infection. Resistance to reinfection holds promise that a vaccine strategy may protect cats and, by extension, humans.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/virologia , Pneumonia Viral/virologia , Animais , Animais Domésticos , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Antígenos Virais/imunologia , Betacoronavirus/imunologia , COVID-19 , Gatos , Infecções por Coronavirus/patologia , Infecções por Coronavirus/transmissão , Modelos Animais de Doenças , Cães , Feminino , Masculino , Pandemias , Pneumonia Viral/patologia , Pneumonia Viral/transmissão , SARS-CoV-2 , Eliminação de Partículas Virais
18.
PLoS Pathog ; 16(3): e1008298, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32134991

RESUMO

Although acute melioidosis is the most common outcome of Burkholderia pseudomallei infection, we have documented a case, P314, where disease severity lessened with time, and the pathogen evolved towards a commensal relationship with the host. In the current study, we used whole-genome sequencing to monitor this long-term symbiotic relationship to better understand B. pseudomallei persistence in P314's sputum despite intensive initial therapeutic regimens. We collected and sequenced 118 B. pseudomallei isolates from P314's airways over a >16-year period, and also sampled the patient's home environment, recovering six closely related B. pseudomallei isolates from the household water system. Using comparative genomics, we identified 126 SNPs in the core genome of the 124 isolates or 162 SNPs/indels when the accessory genome was included. The core SNPs were used to construct a phylogenetic tree, which demonstrated a close relationship between environmental and clinical isolates and detailed within-host evolutionary patterns. The phylogeny had little homoplasy, consistent with a strictly clonal mode of genetic inheritance. Repeated sampling revealed evidence of genetic diversification, but frequent extinctions left only one successful lineage through the first four years and two lineages after that. Overall, the evolution of this population is nonadaptive and best explained by genetic drift. However, some genetic and phenotypic changes are consistent with in situ adaptation. Using a mouse model, P314 isolates caused greatly reduced morbidity and mortality compared to the environmental isolates. Additionally, potentially adaptive phenotypes emerged and included differences in the O-antigen, capsular polysaccharide, motility, and colony morphology. The >13-year co-existence of two long-lived lineages presents interesting hypotheses that can be tested in future studies to provide additional insights into selective pressures, niche differentiation, and microbial adaptation. This unusual melioidosis case presents a rare example of the evolutionary progression towards commensalism by a highly virulent pathogen within a single human host.


Assuntos
Burkholderia pseudomallei/fisiologia , Melioidose/microbiologia , Animais , Antibacterianos/administração & dosagem , Evolução Biológica , Burkholderia pseudomallei/classificação , Burkholderia pseudomallei/genética , Burkholderia pseudomallei/isolamento & purificação , Doença Crônica/terapia , Feminino , Genoma Bacteriano , Humanos , Estudos Longitudinais , Melioidose/tratamento farmacológico , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Filogenia , Simbiose
19.
PLoS Negl Trop Dis ; 14(3): e0008166, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32203536

RESUMO

Flaviviruses such as yellow fever, dengue or Zika viruses are responsible for significant human and veterinary diseases worldwide. These viruses contain an RNA genome, prone to mutations, which enhances their potential to emerge as pathogens. Bamaga virus (BgV) is a mosquito-borne flavivirus in the yellow fever virus group that we have previously shown to be host-restricted in vertebrates and horizontally transmissible by Culex mosquitoes. Here, we aimed to characterise BgV host-restriction and to investigate the mechanisms involved. We showed that BgV could not replicate in a wide range of vertebrate cell lines and animal species. We determined that the mechanisms involved in BgV host-restriction were independent of the type-1 interferon response and RNAse L activity. Using a BgV infectious clone and two chimeric viruses generated as hybrids between BgV and West Nile virus, we demonstrated that BgV host-restriction occurred post-cell entry. Notably, BgV host-restriction was shown to be temperature-dependent, as BgV replicated in all vertebrate cell lines at 34°C but only in a subset at 37°C. Serial passaging of BgV in Vero cells resulted in adaptive mutants capable of efficient replication at 37°C. The identified mutations resulted in amino acid substitutions in NS4A-S124F, NS4B-N244K and NS5-G2C, all occurring close to a viral protease cleavage site (NS4A/2K and NS4B/NS5). These mutations were reverse engineered into infectious clones of BgV, which revealed that NS4B-N244K and NS5-G2C were sufficient to restore BgV replication in vertebrate cells at 37°C, while NS4A-S124F further increased replication efficiency. When these mutant viruses were injected into immunocompetent mice, alongside BgV and West Nile virus chimeras, infection and neurovirulence were enhanced as determined by clinical scores, seroconversion, micro-neutralisation, viremia, histopathology and immunohistochemistry, confirming the involvement of these residues in the attenuation of BgV. Our studies identify a new mechanism of host-restriction and attenuation of a mosquito-borne flavivirus.


Assuntos
Infecções por Flavivirus/virologia , Flavivirus/genética , Flavivirus/patogenicidade , Mutação , Proteínas não Estruturais Virais/genética , Animais , Encéfalo/patologia , Encéfalo/virologia , Linhagem Celular , Chlorocebus aethiops , Culicidae/virologia , Modelos Animais de Doenças , Endorribonucleases/metabolismo , Feminino , Flavivirus/fisiologia , Infecções por Flavivirus/metabolismo , Infecções por Flavivirus/patologia , Células HEK293 , Humanos , Masculino , Camundongos , Mosquitos Vetores/virologia , Células Vero , Virulência/genética , Replicação Viral , Vírus do Nilo Ocidental/genética
20.
Pathogens ; 9(3)2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32156028

RESUMO

The wild pig population on Molokai, Hawaii, USA is a possible reservoir for bovine tuberculosis, caused by Mycobacterium bovis, and has been implicated in decades past as the source of disease for the island's domestic cattle. Heat-inactivated vaccines have been effective for reducing disease prevalence in wild boar in Spain and could prove useful for managing M. bovis in Molokai wild pigs. We designed an experiment to test this vaccine in wild pigs of Molokai genetics. Fifteen 3-4-month-old pigs were orally administered 106-107 colony forming units (cfu) of heat-inactivated M. bovis (Vaccinates; n = 8; 0.2 mL) or phosphate buffered saline (Controls; n = 7; 0.2 mL). Each dose was administered in a 0.5 mL tube embedded in a fruit candy/cracked corn mix. Boosters were given seven weeks post-prime in the same manner and dose. Nineteen weeks post-prime, pigs were orally challenged with 1 × 106 cfu of virulent M. bovis. Twelve weeks post-challenge, pigs were euthanized and necropsied, at which time 23 different tissues from the head, thorax, and abdomen were collected and examined. Each tissue was assigned a lesion score. Ordinal lesion score data were analyzed using non-parametric Wilcoxon Signed Rank test. Effect size was calculated using Cohen's d. Four of eight Vaccinates and four of seven Controls had gross and microscopic lesions, as well as culture-positive tissues. Vaccinates had statistically lower lesion scores than Controls in the following areas: gross thoracic lesion scores (p = 0.013 Cohen's d = 0.33) and microscopic thoracic lesion scores (p = 0.002, Cohen's d = 0.39). There were no differences in head lesion scores alone, both gross and microscopic, nor were there differences when comparing combined gross and microscopic head and thoracic lesion scores. These results are indicative that this vaccination protocol affords a modest degree of infection containment with this vaccine in Molokai wild pigs.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...