RESUMO
Crimean-Congo hemorrhagic fever virus (CCHFV) is a widely distributed tickborne zoonotic agent that infects a variety of host species. There is a lack of information on the true geographic distribution of the prevalence and risk of CCHFV in West Africa. A countrywide cross-sectional study involving 1413 extensively managed indigenous small ruminants and cattle at livestock sales markets and in village herds, respectively, was carried out in The Gambia. In sheep, an overall anti-CCHFV antibody prevalence of 18.9% (95% CI: 15.5-22.8%), goats 9.0% (95% CI: 6.7-11.7%), and cattle 59.9% (95% CI: 54.9-64.7%) was detected. Significant variation (p < 0.05) in the prevalence of anti-CCHFV antibodies at sites in the five administrative regions (sheep: 4.8-25.9%; goats: 1.8-17.1%) and three agroecological zones (sheep: 8.9-32.9%; goats: 4.1-18.0%) was also observed. Comparatively, higher anti-CCHFV antibody prevalence was detected in cattle (33.3-84.0%) compared to small ruminants (1.8-8.1%). This study represents the first countrywide investigation of the seroprevalence of CCHFV in The Gambia, and the results suggest potential circulation and endemicity of the virus in the country. These data provide critical information vital to the development of informed policies for the surveillance, diagnosis, and control of CCFHV infection in The Gambia and the region.
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African swine fever (ASF) is an infectious viral disease caused by African swine fever virus (ASFV), that causes high mortality in domestic swine and wild boar (Sus scrofa). Currently, outbreaks are mitigated through strict quarantine measures and the culling of affected herds, resulting in massive economic losses to the global pork industry. In 2019, an ASFV outbreak was reported in Mongolia, describing a rapidly progressing clinical disease and gross lesions consistent with the acute form of ASF; the virus was identified as a genotype II virus. Due to the limited information on clinical disease and viral dynamics within hosts available from field observations of the Mongolian isolates, we conducted the present study to further evaluate the progression of clinical disease, virulence, and pathology of an ASFV Mongolia/2019 field isolate (ASFV-MNG19), by experimental infection of domestic pigs. Intramuscular inoculation of domestic pigs with ASFV-MNG19 resulted in clinical signs and viremia at 3 days post challenge (DPC). Clinical disease rapidly progressed, resulting in the humane euthanasia of all pigs by 7 DPC. ASFV-MNG19 infected pigs had viremic titers of 108 TCID50/mL by 5 DPC and shed virus in oral secretions late in disease, as determined from oropharyngeal swabs. Whole-genome sequencing confirmed that the ASFV-MNG19 strain used in this study was a genotype II strain highly similar to other regional strains. In conclusion, we demonstrate that ASFV-MNG19 is a virulent genotype II ASFV strain that causes acute ASF in domestic swine.
Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Suínos , Animais , Febre Suína Africana/epidemiologia , Mongólia/epidemiologia , Virulência , Viremia/veterinária , Sus scrofaRESUMO
This study reports the development of multiplex real-time PCR assays for differential detection of capripoxvirus (CaPV), parapoxvirus (PaPV) and foot-and-mouth disease virus (FMDV) in sheep, goats and cattle. Three multiplex assays were developed, a capripox (CaP) rule-out assay for simultaneous detection and differentiation of CaPV and PaPV, a FMD rule-out assay for simultaneous detection and differentiation of FMDV and PaPV, and a FMD/CaP rule-out assay for simultaneous detection and differentiation of CaPV, PaPV and FMDV. All multiplex assays included ß-actin gene ACTB as an internal positive control to monitor PCR inhibition and accuracy of nucleic acid extractions. The optimized assays were highly specific to the target viruses (CaPV, PaPV and FMDV) with no cross-reactivity against other viruses that cause similar clinical signs. Using positive control plasmids as template, the limit of detection (LOD) of the multiplex assays were estimated as 2 CaPV, 7 PaPV and 15 FMDV copies per assay. The amplification efficiency (AE) and correlation coefficient (R2 ), estimated from the standard curves (Ct vs. log10 template dilution), were 94%-106% and >0.99, respectively, for CaP and FMD rule-out assays, 96%-116% (AE) and >0.98 (R2 ), respectively, for CaP/FMD rule-out assays and 91%-102% and >0.99, respectively, for the corresponding singleplex assays. The diagnostic sensitivity (DSe) of the multiplex assays was assessed on 35 CaPV and 39 FMDV clinical specimens from experimentally infected (CS-E) animals, and 29 CaPV (LSDV), 28 FMDV and 36 PaPV clinical specimens from naturally infected (CS-N) animals; all tested positive (DSe 100%) except two CS-E FMDV specimens that were tested negative by FMD rule-out and the corresponding singleplex (FMDV) assays (37/39; DSe 95%). The newly developed multiplex assays offer a valuable tool for differential detection of clinically indistinguishable CaPV, PaPV and FMDV in suspected animals and animals with mixed infections.
Assuntos
Capripoxvirus , Doenças Transmissíveis , Vírus da Febre Aftosa , Febre Aftosa , Doenças das Cabras , Parapoxvirus , Infecções por Poxviridae , Animais , Capripoxvirus/genética , Bovinos , Doenças Transmissíveis/veterinária , Febre Aftosa/diagnóstico , Vírus da Febre Aftosa/genética , Doenças das Cabras/diagnóstico , Parapoxvirus/genética , Infecções por Poxviridae/diagnóstico , Infecções por Poxviridae/veterinária , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Sensibilidade e Especificidade , OvinosRESUMO
The sustained spread of African swine fever (ASF) virus throughout much of the world has made ASF a global animal health priority, with an increased emphasis on enhancing preparedness to prevent, detect and respond to a potential outbreak of ASF virus (ASFV). In the event of ASFV entry to the North American swine population, enhanced surveillance and diagnostic testing strategies will be critical to facilitate progressive response and eradication of the disease. Compared to individual animal sampling, pen-based oral fluid collection for active surveillance is a non-invasive alternative that is less resource and time-intensive. To evaluate the feasibility of using rope-based oral fluid for early detection of ASFV, four independent animal experiments were conducted in weaned pigs housed in numbers that mimic the industry settings, utilising either highly virulent ASFV Georgia 2007/1 strain or moderately virulent ASFV Malta'78 strain. Pen-based oral fluid and individual oropharyngeal swabs were collected daily and blood samples from each animal were collected every other day. All samples were subsequently tested for ASFV by real-time PCR. ASFV genome was detected in individual blood samples as early as one day post-infection and detected in oral fluids at low-to-moderate levels as early as 3-5 days post-infection in all four independent experiments. These results suggest that pen-based oral fluid samples may be used to supplement the use of traditional samples for rapid detection of ASFV during ASF surveillance.
Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Doenças dos Suínos , Febre Suína Africana/diagnóstico , Febre Suína Africana/epidemiologia , Vírus da Febre Suína Africana/genética , Animais , Surtos de Doenças/veterinária , Reação em Cadeia da Polimerase em Tempo Real/veterinária , SuínosRESUMO
An outbreak of rabbit hemorrhagic disease virus 2 (RHDV2)-associated disease occurred in the southwestern United States following its first detection in New Mexico in March 2020. The disease spread throughout several states and was diagnosed for the first time in California on May 11, 2020, in a black-tailed jackrabbit (Lepus californicus). The following day, the California Department of Food and Agriculture (CDFA) issued an order banning the entrance into California of several lagomorph species and their products from any state in which the disease had been detected in the last 12 mo. RHDV2 is a threat to wild lagomorph species in California, including the endangered riparian brush rabbit (Sylvilagus bachmani riparius). Therefore, the California Department of Fish and Wildlife (CDFW) started tracking any mortality event in wild lagomorph populations. As of August 9, 2020, RHDV2 had been detected in wild and domestic lagomorphs of several counties in southern California that were submitted to the California Animal Health and Food Safety laboratory system by the CDFA or the CDFW. These positive cases included 2 additional black-tailed jackrabbits and 3 desert cottontail rabbits (Sylvilagus audubonii). In addition, the infection spilled over to domestic populations, whereby it was confirmed on July 10, 2020, in a domestic rabbit (Oryctolagus cuniculus).
Assuntos
Infecções por Caliciviridae/veterinária , Surtos de Doenças/veterinária , Vírus da Doença Hemorrágica de Coelhos , Coelhos/virologia , Animais , Animais Selvagens , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Lebres/virologia , Sudoeste dos Estados Unidos/epidemiologiaRESUMO
Binary ethylenimine (BEI) has been widely used as a virucide to inactivate viruses. For regulatory exclusion of a select agent, the United States Federal Select Agent Program (FSAP) requires an inactivation procedure that renders a select agent non-viable but allows the select agent to retain antigenic characteristics for future use must be validated, and the inactivated agent must be confirmed by a viability testing. In this curve-based validation study, we examined impacts of BEI concentration, treatment temperature, and time on our in-house inactivation procedures of Foot-and-Mouth Disease Virus (FMDV), Vesicular Stomatitis Virus (VSV), and Swine Vesicular Disease Virus (SVDV). The inactivation efficacy was confirmed by virus titration and 3 consecutive blind passages on the monolayers of susceptible cells. A linear correlation between the virus titer reduction and BEI concentration, treatment time, and temperature was established. The results confirmed our in-house BEI inactivation procedure of two doses of 1.5 mM BEI treatment at 37 °C, 1st dose for 24 h, then 2nd dose for 6 more hours for a total of 30 h BEI contact time, can ensure complete inactivation of FMDV, VSV, and SVDV.
Assuntos
Aziridinas/farmacologia , Enterovirus Humano B/efeitos dos fármacos , Vírus da Febre Aftosa/efeitos dos fármacos , Febre Aftosa/prevenção & controle , Doenças dos Suínos/prevenção & controle , Estomatite Vesicular/prevenção & controle , Vírus da Estomatite Vesicular Indiana/efeitos dos fármacos , Animais , Contenção de Riscos Biológicos/veterinária , Suínos , Doenças dos Suínos/virologia , Estomatite Vesicular/virologia , Inativação de Vírus/efeitos dos fármacosRESUMO
Real-time PCR assays are highly sensitive, specific and rapid techniques for the identification of ASF virus (ASFV) (Section 3.8, OIE Terrestrial Manual, 2019). Although an ASFV p72 gene-based real-time PCR assay (a.k.a. the Zsak assay) (Journal of Clinical Microbiology, 2005, 43, 112) has been widely used for ASFV detection, several more ASFV whole genome sequences have become available in the 15 years since the design of the Zsak assay. In this study, we developed a new ASFV p72 gene-based real-time PCR after analysis of all currently available sequences of the p72 gene and multiplexed the new assay with a modified Zsak assay aiming to have a broader coverage of ASFV strain/isolates. To reduce false-negative detections, porcine house-keeping gene, beta actin (ACTB), was applied as an internal control. Eight ACTB sequences from the GenBank and 61 partial ACTB sequences generated in this study, and 1,012 p72 sequences from the GenBank and 23 p72 sequences generated at FADDL, were used for ACTB and ASFV primer and probe designs, respectively, to ensure broader host and ASFV coverage. Multiplexing ACTB in the reaction did not affect ASFV amplification. The multiplex assay was evaluated for strain/isolate coverage, sensitivity and specificity. The in silico analysis showed high ASFV strain/isolate coverage: 98.4% (978/994) of all p72 sequences currently available. The limit of detection (LOD) was 6 plasmid copies or 0.1-1 TCID50 /ml of ASFV isolates per reaction. Only targeted ASFV isolates and the viruses in the positive clinical samples were detected, indicating that the assay is highly specific (100% specificity). The test results of 26 ASFV isolates with different country origins showed that this newly developed multiplex assay performed better than the Zsak assay that has been widely accepted and used worldwide, indicating that it may be used as an alternative assay for ASFV detection.
Assuntos
Vírus da Febre Suína Africana/isolamento & purificação , Febre Suína Africana/diagnóstico , Febre Suína Africana/virologia , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Actinas/genética , Vírus da Febre Suína Africana/genética , Animais , Primers do DNA , Sondas de DNA , DNA Viral/genética , Sensibilidade e Especificidade , SuínosRESUMO
African swine fever (ASF) is one of the most complex and lethally haemorrhagic viral diseases of swine, affecting all breeds and ages of pigs. In the absence of ASF vaccines, reliable laboratory diagnosis and restricted biosecurity are critical for disease prevention and control. A detection of ASF-specific antibodies in an unvaccinated pig is a good marker for the diagnosis of ASF. The immunoperoxidase test (IPT) is a sensitive test for detecting ASF virus (ASFV) antibodies. However, due to the complexity of the procedure, the IPT is only suitable to be used as a confirmatory test. The ASFV p30 protein-based enzyme-linked immunosorbent assay (ELISA) is widely used for ASFV antibody screening, but the sensitivity is not comparable to the IPT. It is essential to have a better understanding of the antigenic properties of ASFV p30 to improve p30-based serologic tests. In this study, we developed a panel of 21 monoclonal antibodies (mAbs) against ASFV p30. With 14 out of the 21 mAbs, we defined 4 antigenic regions that contain at least 4 linear epitopes. Nine of the 14 mAbs mapped to antigenic regions 3 and 4 reacted with p30 in all serologic methods tested in this study, such as indirect immunofluorescence assay (IFA), ELISA and Western blot. The antigenic regions 3 and 4 are highly conserved and immunodominant in host antibody response. These mAbs and the defined p30 antigenic regions 3 and 4 provide valuable tools for the development and improvement of ASF serologic assays.
RESUMO
Peste des petits ruminants (PPR) is an acute and highly contagious disease with high mortality in small ruminants and significant socioeconomic impact in developing countries. The causative agent is peste des petits ruminants virus (PPRV). The Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health (OIE) have set up a goal for the global eradication of PPR by 2030. To assist in this effort, an easily produced, specific, non-pathogenic bacteriophage Qß based real-time RT-PCR (qRT-PCR) PPRV positive control was developed. This control is compatible for use with two previously described PPRV qRT-PCR assays either as singleplex or multiplex platform. Additionally, the control can also be used for assembling proficiency testing panels for competency testing in diagnostic laboratories. Use of the Qß phage based PPRV control as a positive control or in proficiency testing panels reduces the risk of inadvertent release of pathogenic PPRV from diagnostic laboratories, which would be especially important should PPR be eradicated in the future.
Assuntos
Bacteriófagos/genética , Peste dos Pequenos Ruminantes/diagnóstico , Vírus da Peste dos Pequenos Ruminantes/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Animais , Primers do DNA/genética , Sondas de DNA/genética , Doenças das Cabras/diagnóstico , Doenças das Cabras/virologia , Cabras , Vírus da Peste dos Pequenos Ruminantes/genética , Padrões de Referência , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sensibilidade e Especificidade , Ovinos , Doenças dos Ovinos/diagnóstico , Doenças dos Ovinos/virologiaRESUMO
Foot-and-mouth disease virus (FMDV) causes a highly contagious and economically important vesicular disease in cloven-hoofed animals that is clinically indistinguishable from symptoms caused by Seneca Valley virus 1 (SVV-1). To differentiate SVV-1 from FMDV infections, we developed a SVV-1 real-time RT-PCR (RT-qPCR) assay and multiplexed with published FMDV assays. Two published FMDV assays (Journal of the American Veterinary Medical Association, 220, 2002, 1636; Journal of Virological Methods, 236, 2016, 258) targeting the 3D polymerase (3D) region were selected and multiplexed with the SVV-1 assay that has two targets, one in the 5' untranslated region (5' UTR, this study) and the other in the 3D region (Journal of Virological Methods, 239, 2017, 34). In silico analysis showed that the primers and probes of SVV-1 assay matched 98.3% of the strain sequences (113/115). The primer and probe sequences of the Shi FMDV assay matched 85.4% (806/944), and that of the Callahan FMDV assay matched 62.7% (592/944) of the sequences. The limit of detection (LOD) for the two multiplex RT-qPCR assays for SVV-1 was both 9 copies per reaction by cloned positive plasmids and 0.16 TCID50 per reaction by cell culture. The LOD for FMDV by both multiplex assays was 11 copies per reaction using cloned positive plasmids. With cell cultures of the seven serotypes of FMDV, the Shi assay (Journal of Virological Methods, 236, 2016, 258) had LODs between 0.04 and 0.18 TCID50 per reaction that were either the same or lower than the Callahan assay. Interestingly, multiplexing with SVV-1 increased the amplification efficiencies of the Callahan assay (Journal of the American Veterinary Medical Association, 220, 2002, 1636) from 51.5%-66.7% to 89.5%-96.6%. Both assays specifically detected the target viruses without cross-reacting to SVV-1 or to other common porcine viruses. An 18S rRNA housekeeping gene that was amplified from multiple cloven-hoofed animal species was used as an internal control. The prevalence study did not detect any FMDV, but SVV-1 was detected from multiple types of swine samples with an overall positive rate of 10.5% for non-serum samples.
Assuntos
Vírus da Febre Aftosa/isolamento & purificação , Febre Aftosa/virologia , Reação em Cadeia da Polimerase Multiplex/veterinária , Doenças dos Suínos/virologia , Regiões 5' não Traduzidas/genética , Animais , Primers do DNA/genética , Vírus da Febre Aftosa/genética , Vírus da Febre Aftosa/imunologia , Limite de Detecção , Picornaviridae/genética , Picornaviridae/isolamento & purificação , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Sensibilidade e Especificidade , Sorogrupo , SuínosRESUMO
African swine fever virus (ASFV) is the causative agent of a severe and highly contagious viral disease of pigs that poses serious economic consequences to the swine industry due to the high mortality rate and impact on international trade. There is no effective vaccine to control African swine fever (ASF), and therefore, efficient disease control is dependent on early detection and diagnosis of ASFV. The large size of the ASFV genome (â¼180 kb) has historically hindered efforts to rapidly obtain a full-genome sequence. Rapid acquisition of data is critical for characterization of the isolate and to support epidemiological efforts. Here, we investigated the capacity of the Oxford Nanopore MinION sequence sensing device to act as a rapid sequencing tool. When coupled with our novel companion software script, the African swine fever fast analysis sequencing tool (ASF-FAST), the analysis of output data was performed in real time. Complete ASFV genome sequences were generated from cell culture isolates and blood samples obtained from experimentally infected pigs. Removal of the host-methylated DNA from the extracted nucleic acid facilitated rapid ASFV sequence identification, with reads specific to ASFV detected within 6 min after the initiation of sequencing. Regardless of the starting material, sufficient sequence was available for complete genome resolution (up to 100%) within 10 min. Overall, this paper highlights the use of Nanopore sequencing technology in combination with the ASF-FAST software for the purpose of rapid and real-time resolution of the full ASFV genome from a diagnostic sample.
Assuntos
Vírus da Febre Suína Africana/classificação , Vírus da Febre Suína Africana/genética , Febre Suína Africana/diagnóstico , Febre Suína Africana/virologia , Biologia Computacional/métodos , Sequenciamento por Nanoporos , Software , Vírus da Febre Suína Africana/isolamento & purificação , Animais , Genoma Viral , Sequenciamento de Nucleotídeos em Larga Escala , Sequenciamento por Nanoporos/métodos , Kit de Reagentes para Diagnóstico , Reprodutibilidade dos Testes , Análise de Sequência de DNA , SuínosRESUMO
During the Ebola virus outbreak of 2013-2016, the Viral Special Pathogens Branch field laboratory in Sierra Leone tested approximately 26 000 specimens between August 2014 and October 2015. Analysis of the B2M endogenous control Ct values showed its utility in monitoring specimen quality, comparing results with different specimen types, and interpretation of results. For live patients, blood is the most sensitive specimen type and oral swabs have little diagnostic utility. However, swabs are highly sensitive for diagnostic testing of corpses.
Assuntos
Surtos de Doenças , Ebolavirus/isolamento & purificação , Doença pelo Vírus Ebola/diagnóstico , RNA Viral/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Serviços de Laboratório Clínico , Ebolavirus/genética , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/virologia , Humanos , Laboratórios , Reação em Cadeia da Polimerase em Tempo Real/métodos , Sensibilidade e Especificidade , Serra Leoa/epidemiologiaRESUMO
Hantavirus pulmonary syndrome (HPS) is a severe disease caused by hantavirus infection of pulmonary microvascular endothelial cells leading to microvascular leakage, pulmonary edema, pleural effusion and high case fatality. Previously, we demonstrated that Andes virus (ANDV) infection caused up-regulation of vascular endothelial growth factor (VEGF) and concomitant downregulation of the cellular adhesion molecule VE-cadherin leading to increased permeability. Analyses of human HPS-patient sera have further demonstrated increased circulating levels of VEGF. Here we investigate the impact of a small molecule antagonist of the VEGF receptor 2 (VEGFR-2) activation in vitro, and overall impact on survival in the Syrian hamster model of HPS.
Assuntos
Síndrome Pulmonar por Hantavirus/virologia , Orthohantavírus/efeitos dos fármacos , Orthohantavírus/fisiologia , Piperidinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Quinazolinas/farmacologia , Animais , Permeabilidade Capilar/efeitos dos fármacos , Cricetinae , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Células Endoteliais/virologia , Síndrome Pulmonar por Hantavirus/metabolismo , Síndrome Pulmonar por Hantavirus/mortalidade , Fosforilação/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/metabolismo , Carga ViralRESUMO
Animal models recapitulating human Ebola virus disease (EVD) are critical for insights into virus pathogenesis. Ebola virus (EBOV) isolates derived directly from human specimens do not, without adaptation, cause disease in immunocompetent adult rodents. Here, we describe EVD in mice engrafted with human immune cells (hu-BLT). hu-BLT mice developed EVD following wild-type EBOV infection. Infection with high-dose EBOV resulted in rapid, lethal EVD with high viral loads, alterations in key human antiviral immune cytokines and chemokines, and severe histopathologic findings similar to those shown in the limited human postmortem data available. A dose- and donor-dependent clinical course was observed in hu-BLT mice infected with lower doses of either Mayinga (1976) or Makona (2014) isolates derived from human EBOV cases. Engraftment of the human cellular immune system appeared to be essential for the observed virulence, as nonengrafted mice did not support productive EBOV replication or develop lethal disease. hu-BLT mice offer a unique model for investigating the human immune response in EVD and an alternative animal model for EVD pathogenesis studies and therapeutic screening.
Assuntos
Ebolavirus/fisiologia , Regulação da Expressão Gênica/imunologia , Doença pelo Vírus Ebola/imunologia , Animais , Encéfalo/virologia , Citocinas/genética , Citocinas/metabolismo , Doença pelo Vírus Ebola/urina , Doença pelo Vírus Ebola/virologia , Humanos , Rim/virologia , Fígado/virologia , Pulmão/virologia , Masculino , Camundongos , Camundongos Transgênicos , RNA Viral/isolamento & purificação , Baço/virologia , Testículo/virologia , Replicação ViralRESUMO
In August 2014, the Viral Special Pathogens Branch of the US Centers for Disease Control and Prevention established a field laboratory in Sierra Leone in response to the ongoing Ebola virus outbreak. Through March 2015, this laboratory tested >12 000 specimens from throughout Sierra Leone. We describe the organization and procedures of the laboratory located in Bo, Sierra Leone.
Assuntos
Ebolavirus/isolamento & purificação , Doença pelo Vírus Ebola/diagnóstico , Doença pelo Vírus Ebola/virologia , Centers for Disease Control and Prevention, U.S. , Surtos de Doenças , Epidemias , Humanos , Laboratórios , Serra Leoa/epidemiologia , Estados UnidosRESUMO
In October 2012, a cluster of illnesses and deaths was reported in Uganda and was confirmed to be an outbreak of Marburg virus disease (MVD). Patients meeting the case criteria were interviewed using a standard investigation form, and blood specimens were tested for evidence of acute or recent Marburg virus infection by reverse transcription-polymerase chain reaction (RT-PCR) and antibody enzyme-linked immunosorbent assay. The total count of confirmed and probable MVD cases was 26, of which 15 (58%) were fatal. Four of 15 laboratory-confirmed cases (27%) were fatal. Case patients were located in 4 different districts in Uganda, although all chains of transmission originated in Ibanda District, and the earliest case detected had an onset in July 2012. No zoonotic exposures were identified. Symptoms significantly associated with being a MVD case included hiccups, anorexia, fatigue, vomiting, sore throat, and difficulty swallowing. Contact with a case patient and attending a funeral were also significantly associated with being a case. Average RT-PCR cycle threshold values for fatal cases during the acute phase of illness were significantly lower than those for nonfatal cases. Following the institution of contact tracing, active case surveillance, care of patients with isolation precautions, community mobilization, and rapid diagnostic testing, the outbreak was successfully contained 14 days after its initial detection.
Assuntos
Doença do Vírus de Marburg/epidemiologia , Marburgvirus/isolamento & purificação , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Surtos de Doenças , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Doença do Vírus de Marburg/virologia , Pessoa de Meia-Idade , Uganda/epidemiologia , Adulto JovemRESUMO
The 2013-2015 Ebola virus disease (EVD) epidemic is caused by the Makona variant of Ebola virus (EBOV). Early in the epidemic, genome sequencing provided insights into virus evolution and transmission and offered important information for outbreak response. Here, we analyze sequences from 232 patients sampled over 7 months in Sierra Leone, along with 86 previously released genomes from earlier in the epidemic. We confirm sustained human-to-human transmission within Sierra Leone and find no evidence for import or export of EBOV across national borders after its initial introduction. Using high-depth replicate sequencing, we observe both host-to-host transmission and recurrent emergence of intrahost genetic variants. We trace the increasing impact of purifying selection in suppressing the accumulation of nonsynonymous mutations over time. Finally, we note changes in the mucin-like domain of EBOV glycoprotein that merit further investigation. These findings clarify the movement of EBOV within the region and describe viral evolution during prolonged human-to-human transmission.
Assuntos
Ebolavirus/genética , Ebolavirus/isolamento & purificação , Genoma Viral , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/virologia , Mutação , Evolução Biológica , Surtos de Doenças , Ebolavirus/classificação , Doença pelo Vírus Ebola/transmissão , Humanos , Serra Leoa/epidemiologia , Manejo de EspécimesRESUMO
Many U.S. medical schools have developed curricula in geriatric medicine to address the growing older adult population. At our university, the authors have integrated an assisted living facility (ALF) program into a required first-year clinical skills course. During the 2011 to 2012 academic year, an electronic survey was distributed to 109 first-year medical students prior to and after the program. Eighty-eight percent and 85% of students completed the pre- and postintervention survey, respectively. Students reported a positive attitude toward caring for older adults (92.5% post- vs. 80.2% preintervention), an understanding of the medical and social needs of older adults (89.2% post- vs. 38.5% preintervention), an acquisition of the skills to assess the health of older adults (71% post- vs. 14.5% preintervention), and an understanding of ALFs as nonmedical supportive housing (92.5% post- vs. 70.8% preintervention). The authors' curriculum offers an innovative method to integrate geriatrics education early in medical education and to involve medical students in their community.
Assuntos
Moradias Assistidas/métodos , Estágio Clínico , Competência Clínica , Currículo , Geriatria/educação , Estudantes de Medicina/psicologia , Adulto , Estágio Clínico/métodos , Estágio Clínico/organização & administração , Educação de Graduação em Medicina/métodos , Educação de Graduação em Medicina/organização & administração , Feminino , Humanos , Masculino , Inquéritos e Questionários , Estados UnidosAssuntos
Quirópteros/fisiologia , Doença do Vírus de Marburg/prevenção & controle , Marburgvirus/isolamento & purificação , Animais , Quirópteros/virologia , Surtos de Doenças , Variação Genética , Humanos , Doença do Vírus de Marburg/epidemiologia , Marburgvirus/genética , Filogenia , RNA Viral/genética , Uganda/epidemiologiaRESUMO
BACKGROUND: Rift Valley fever virus (RVFV) causes outbreaks of severe disease in livestock and humans throughout Africa and the Arabian Peninsula. In people, RVFV generally causes a self-limiting febrile illness but in a subset of individuals, it progresses to more serious disease. One manifestation is a delayed-onset encephalitis that can be fatal or leave the afflicted with long-term neurologic sequelae. In order to design targeted interventions, the basic pathogenesis of RVFV encephalitis must be better understood. METHODOLOGY/PRINCIPAL FINDINGS: To characterize the host immune responses and viral kinetics associated with fatal and nonfatal infections, mice were infected with an attenuated RVFV lacking NSs (ΔNSs) that causes lethal disease only when administered intranasally (IN). Following IN infection, C57BL/6 mice developed severe neurologic disease and succumbed 7-9 days post-infection. In contrast, inoculation of ΔNSs virus subcutaneously in the footpad (FP) resulted in a subclinical infection characterized by a robust immune response with rapid antibody production and strong T cell responses. IN-inoculated mice had delayed antibody responses and failed to clear virus from the periphery. Severe neurological signs and obtundation characterized end stage-disease in IN-inoculated mice, and within the CNS, the development of peak virus RNA loads coincided with strong proinflammatory responses and infiltration of activated T cells. Interestingly, depletion of T cells did not significantly alter survival, suggesting that neurologic disease is not a by-product of an aberrant immune response. CONCLUSIONS/SIGNIFICANCE: Comparison of fatal (IN-inoculated) and nonfatal (FP-inoculated) ΔNSs RVFV infections in the mouse model highlighted the role of the host immune response in controlling viral replication and therefore determining clinical outcome. There was no evidence to suggest that neurologic disease is immune-mediated in RVFV infection. These results provide important insights for the future design of vaccines and therapeutic options.