Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-30 (of 42 Records) |
Query Trace: Chakrabarti A [original query] |
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Cost of acute respiratory illness episode and its determinants among community-dwelling older adults: a four-site cohort study from India
Krishnan A , Shekhawat K , Ortega-Sanchez IR , Kanungo S , Rajkumar P , Bhardwaj SD , Kumar R , Prabhakaran AO , Gopal G , Chakrabarti AK , Purushothaman GKC , Potdar V , Manna B , Gharpure R , Amarchand R , Choudekar A , Lafond KE , Dar L , Bhattacharjee U , Azziz-Baumgartner E , Saha S . BMJ Public Health 2023 1 (1) e000103 INTRODUCTION: Advocacy for the provision of public health resources, including vaccine for the prevention of acute respiratory illnesses (ARIs) among older adults in India, needs evidence on costs and benefits. Using a cohort of community-dwelling adults aged 60 years and older in India, we estimated the cost of ARI episode and its determinants. METHODS: We enrolled 6016 participants in Ballabgarh, Chennai, Kolkata and Pune from July 2018 to March 2020. They were followed up weekly to identify ARI and classified them as acute upper respiratory illness (AURI) or pneumonia based on clinical features based on British Thoracic Society guidelines. All pneumonia and 20% of AURI cases were asked about the cost incurred on medical consultation, investigation, medications, transportation, food and lodging. The cost of services at public facilities was supplemented by WHO-Choosing Interventions that are Cost-Effective(CHOICE) estimates for 2019. Indirect costs incurred by the affected participant and their caregivers were estimated using human capital approach. We used generalised linear model with log link and gamma family to identify the average marginal effect of key determinants of the total cost of ARI. RESULTS: We included 2648 AURI and 1081 pneumonia episodes. Only 47% (range 36%-60%) of the participants with pneumonia sought care. The mean cost of AURI episode was US$13.9, while that of pneumonia episode was US$25.6, with indirect costs comprising three-fourths of the total. The cost was higher among older men by US$3.4 (95% CI: 1.4 to 5.3), those with comorbidities by US$4.3 (95% CI: 2.8 to 5.7) and those who sought care by US$17.2 (95% CI: 15.1 to 19.2) but not by influenza status. The mean per capita annual cost of respiratory illness was US$29.5. CONCLUSION: Given the high community disease and cost burden of ARI, intensifying public health interventions to prevent and mitigate ARI among this fast-growing older adult population in India is warranted. |
HIV and fungal priority pathogens
Sati H , Alastruey-Izquierdo A , Perfect J , Govender NP , Harrison TS , Chiller T , Sorrell TC , Bongomin F , Oladele R , Chakrabarti A , Wahyuningsih R , Colombo AL , Rodriguez-Tudela JL , Beyrer C , Ford N . Lancet HIV 2023 10 (11) e750-e754 The burden of invasive fungal infections associated with opportunistic fungal pathogens is a persistent challenge, particularly among people with advanced HIV disease. In October, 2022, WHO published the Fungal Priority Pathogens List (FPPL)-the first global effort to systematically prioritise fungal pathogens. Of the 19 pathogens in the WHO FPPL, four opportunistic pathogens in particular cause invasive diseases in people living with HIV: Cryptococcus neoformans, Histoplasma spp, Pneumocystis jirovecii, and Talaromyces marneffei. These four fungal pathogens are major causes of illness and death in people with advanced HIV and overwhelmingly affect those in low-income and middle-income countries. Access to diagnostics, improved surveillance, targeted support for innovation, and an enhanced public health focus on these diseases are needed in the effort to reduce HIV-associated deaths. |
Adjunctive diagnostic studies completed following detection of candidemia in children: Secondary analysis of observed practice from a multicenter cohort study conducted by The Pediatric Fungal Network
Wattier RL , Bucayu RFT , Boge CLK , Ross RK , Yildirim I , Zaoutis TE , Palazzi DL , Vora SB , Castagnola E , Avilés-Robles M , Danziger-Isakov L , Tribble AC , Sharma TS , Arrieta AC , Maron G , Berman DM , Yin DE , Sung L , Green M , Roilides E , Belani K , Romero J , Soler-Palacin P , López-Medina E , Nolt D , Bin Hussain IZ , Muller WJ , Hauger SB , Halasa N , Dulek D , Pong A , Gonzalez BE , Abzug MJ , Carlesse F , Huppler AR , Rajan S , Aftandilian C , Ardura MI , Chakrabarti A , Hanisch B , Salvatore CM , Klingspor L , Knackstedt ED , Lutsar I , Santolaya ME , Shuster S , Johnson SK , Steinbach WJ , Fisher BT . J Pediatric Infect Dis Soc 2023 12 (9) 487-495 BACKGROUND: Adjunctive diagnostic studies (aDS) are recommended to identify occult dissemination in patients with candidemia. Patterns of evaluation with aDS across pediatric settings are unknown. METHODS: Candidemia episodes were included in a secondary analysis of a multicenter comparative effectiveness study that prospectively enrolled participants age 120 days -17 years with invasive candidiasis (predominantly candidemia) from 2014-2017. Ophthalmologic examination, abdominal imaging, echocardiogram, neuroimaging, and lumbar puncture were performed per clinician discretion. aDS performance and positive results were determined per episode, within 30 days from candidemia onset. Associations of aDS performance with episode characteristics were evaluated via mixed effects logistic regression. RESULTS: In 662 pediatric candidemia episodes, 490 (74%) underwent abdominal imaging, 450 (68%) ophthalmologic examination, 426 (64%) echocardiogram, 160 (24%) neuroimaging, and 76 (11%) lumbar puncture; performance of each aDS per episode varied across sites up to 16-fold. Longer durations of candidemia were associated with undergoing ophthalmologic examination, abdominal imaging, and echocardiogram. Immunocompromised status (58% of episodes) was associated with undergoing abdominal imaging (aOR 2.38; 95% CI 1.51-3.74). Intensive care at candidemia onset (30% of episodes) was associated with undergoing echocardiogram (aOR 2.42; 95% CI 1.51-3.88). Among evaluated episodes, positive ophthalmologic examination was reported in 15 (3%), abdominal imaging in 30 (6%), echocardiogram in 14 (3%), neuroimaging in 9 (6%) and lumbar puncture in 3 (4%). CONCLUSIONS: Our findings show heterogeneity in practice, with some clinicians performing aDS selectively, potentially influenced by clinical factors. The low frequency of positive results suggests that targeted application of aDS is warranted. |
Assessment of anti-SARS-CoV-2 antibody levels among university students vaccinated with different COVID-19 primary and booster doses - fall 2021, Wisconsin
DeJonge PM , Lambrou AS , Segaloff HE , Bateman A , Sterkel A , Griggs C , Baggott J , Kelly P , Thornburg N , Epperson M , Desamu-Thorpe R , Abedi G , Hsu CH , Nakayama JY , Ruffin J , Turner-Harper D , Matanock A , Almendares O , Whaley M , Chakrabarti A , DeGruy K , Daly M , Westergaard R , Tate JE , Kirking HL . BMC Infect Dis 2023 23 (1) 374 BACKGROUND: University students commonly received COVID-19 vaccinations before returning to U.S. campuses in the Fall of 2021. Given likely immunologic variation among students based on differences in type of primary series and/or booster dose vaccine received, we conducted serologic investigations in September and December 2021 on a large university campus in Wisconsin to assess anti-SARS-CoV-2 antibody levels. METHODS: We collected blood samples, demographic information, and COVID-19 illness and vaccination history from a convenience sample of students. Sera were analyzed for both anti-spike (anti-S) and anti-nucleocapsid (anti-N) antibody levels using World Health Organization standardized binding antibody units per milliliter (BAU/mL). Levels were compared across categorical primary COVID-19 vaccine series received and binary COVID-19 mRNA booster status. The association between anti-S levels and time since most recent vaccination dose was estimated by mixed-effects linear regression. RESULTS: In total, 356 students participated, of whom 219 (61.5%) had received a primary vaccine series of Pfizer-BioNTech or Moderna mRNA vaccines and 85 (23.9%) had received vaccines from Sinovac or Sinopharm. Median anti-S levels were significantly higher for mRNA primary vaccine series recipients (2.90 and 2.86 log [BAU/mL], respectively), compared with those who received Sinopharm or Sinovac vaccines (1.63 and 1.95 log [BAU/mL], respectively). Sinopharm and Sinovac vaccine recipients were associated with a significantly faster anti-S decline over time, compared with mRNA vaccine recipients (P <.001). By December, 48/172 (27.9%) participants reported receiving an mRNA COVID-19 vaccine booster, which reduced the anti-S antibody discrepancies between primary series vaccine types. CONCLUSIONS: Our work supports the benefit of heterologous boosting against COVID-19. COVID-19 mRNA vaccine booster doses were associated with increases in anti-SARS-CoV-2 antibody levels; following an mRNA booster dose, students with both mRNA and non-mRNA primary series receipt were associated with comparable levels of anti-S IgG. |
Perspective: Human milk composition and related data for national health and nutrition monitoring and related research
Ahuja JKC , Casavale KO , Li Y , Hopperton KE , Chakrabarti S , Hines EP , Brooks SPJ , Bondy GS , MacFarlane AJ , Weiler HA , Wu X , Borghese MM , Ahluwalia N , Cheung W , Vargas AJ , Arteaga S , Lombo T , Fisher MM , Hayward D , Pehrsson PR . Adv Nutr 2022 13 (6) 2098-2114 National health and nutrition monitoring is an important federal effort in the United States and Canada, and the basis for many of their nutrition and health policies. Understanding of child exposures through human milk (HM) remains out of reach due to lack of current and representative data on HM's composition and intake volume. This article provides an overview of the current national health and nutrition monitoring activities for HM-fed children, HM composition (HMC) and volume data used for exposure assessment, categories of potential measures in HM, and associated variability factors. In this Perspective, we advocate for a framework for collection and reporting of HMC data for national health and nutrition monitoring and programmatic needs, including a shared vision for a publicly available Human Milk Composition Data Repository (HMCD-R) to include essential metadata associated with HMC. HMCD-R can provide a central, integrated platform for researchers and public health officials for compiling, evaluating, and sharing HMC data. The compiled compositional and metadata in HMCD-R would provide pertinent measures of central tendency and variability and allow use of modeling techniques to approximate compositional profiles for subgroups, providing more accurate exposure assessments for purposes of monitoring and surveillance. HMC and related metadata could facilitate understanding the complexity and variability of HM composition, provide crucial data for assessment of infant and maternal nutritional needs, and inform public health policies, food and nutrition programs, and clinical practice guidelines. |
Health-care-associated bloodstream and urinary tract infections in a network of hospitals in India: a multicentre, hospital-based, prospective surveillance study
Mathur P , Malpiedi P , Walia K , Srikantiah P , Gupta S , Lohiya A , Chakrabarti A , Ray P , Biswal M , Taneja N , Rupali P , Balaji V , Rodrigues C , Lakshmi Nag V , Tak V , Venkatesh V , Mukhopadhyay C , Deotale V , Padmaja K , Wattal C , Bhattacharya S , Karuna T , Behera B , Singh S , Nath R , Ray R , Baveja S , Fomda BA , Sulochana Devi K , Das P , Khandelwal N , Verma P , Bhattacharyya P , Gaind R , Kapoor L , Gupta N , Sharma A , VanderEnde D , Siromany V , Laserson K , Guleria R . Lancet Glob Health 2022 10 (9) e1317-e1325 BACKGROUND: Health-care-associated infections (HAIs) cause significant morbidity and mortality globally, including in low-income and middle-income countries (LMICs). Networks of hospitals implementing standardised HAI surveillance can provide valuable data on HAI burden, and identify and monitor HAI prevention gaps. Hospitals in many LMICs use HAI case definitions developed for higher-resourced settings, which require human resources and laboratory and imaging tests that are often not available. METHODS: A network of 26 tertiary-level hospitals in India was created to implement HAI surveillance and prevention activities. Existing HAI case definitions were modified to facilitate standardised, resource-appropriate surveillance across hospitals. Hospitals identified health-care-associated bloodstream infections and urinary tract infections (UTIs) and reported clinical and microbiological data to the network for analysis. FINDINGS: 26 network hospitals reported 2622 health-care-associated bloodstream infections and 737 health-care-associated UTIs from 89 intensive care units (ICUs) between May 1, 2017, and Oct 31, 2018. Central line-associated bloodstream infection rates were highest in neonatal ICUs (>20 per 1000 central line days). Catheter-associated UTI rates were highest in paediatric medical ICUs (4·5 per 1000 urinary catheter days). Klebsiella spp (24·8%) were the most frequent organism in bloodstream infections and Candida spp (29·4%) in UTIs. Carbapenem resistance was common in Gram-negative infections, occurring in 72% of bloodstream infections and 76% of UTIs caused by Klebsiella spp, 77% of bloodstream infections and 76% of UTIs caused by Acinetobacter spp, and 64% of bloodstream infections and 72% of UTIs caused by Pseudomonas spp. INTERPRETATION: The first standardised HAI surveillance network in India has succeeded in implementing locally adapted and context-appropriate protocols consistently across hospitals and has been able to identify a large number of HAIs. Network data show high HAI and antimicrobial resistance rates in tertiary hospitals, showing the importance of implementing multimodal HAI prevention and antimicrobial resistance containment strategies. FUNDING: US Centers for Disease Control and Prevention cooperative agreement with All India Institute of Medical Sciences, New Delhi. TRANSLATION: For the Hindi translation of the abstract see Supplementary Materials section. |
SARS-CoV-2 infection risk among vaccinated and unvaccinated household members during the Alpha variant surge - Denver, Colorado, and San Diego, California, January-April 2021.
McCormick DW , Konkle SL , Magleby R , Chakrabarti AK , Cherney B , Lindell K , Namageyo-Funa A , Visser S , Soto RA , Donnelly MAP , Stringer G , Austin B , Beatty ME , Stous S , Albanese BA , Chu VT , Chuey M , Dietrich EA , Drobeniuc J , Folster JM , Killerby ME , Lehman JA , McDonald EC , Ruffin J , Schwartz NG , Sheldon SW , Sleweon S , Thornburg NJ , Hughes LJ , Petway M , Tong S , Whaley MJ , Kirking HL , Tate JE , Hsu CH , Matanock A . Vaccine 2022 40 (33) 4845-4855 BACKGROUND: COVID-19 vaccination reduces SARS-CoV-2 infection and transmission. However, evidence is emerging on the degree of protection across variants and in high-transmission settings. To better understand the protection afforded by vaccination specifically in a high-transmission setting, we examined household transmission of SARS-CoV-2 during a period of high community incidence with predominant SARS-CoV-2 B.1.1.7 (Alpha) variant, among vaccinated and unvaccinated contacts. METHODS: We conducted a household transmission investigation in San Diego County, California, and Denver, Colorado, during January-April 2021. Households were enrolled if they had at least one person with documented SARS-CoV-2 infection. We collected nasopharyngeal swabs, blood, demographic information, and vaccination history from all consenting household members. We compared infection risks (IRs), RT-PCR cycle threshold values, SARS-CoV-2 culture results, and antibody statuses among vaccinated and unvaccinated household contacts. RESULTS: We enrolled 493 individuals from 138 households. The SARS-CoV-2 variant was identified from 121/138 households (88%). The most common variants were Alpha (75/121, 62%) and Epsilon (19/121, 16%). There were no households with discordant lineages among household members. One fully vaccinated secondary case was symptomatic (13%); the other 5 were asymptomatic (87%). Among unvaccinated secondary cases, 105/108 (97%) were symptomatic. Among 127 households with a single primary case, the IR for household contacts was 45% (146/322; 95% Confidence Interval [CI] 40-51%). The observed IR was higher in unvaccinated (130/257, 49%, 95% CI 45-57%) than fully vaccinated contacts (6/26, 23%, 95% CI 11-42%). A lower proportion of households with a fully vaccinated primary case had secondary cases (1/5, 20%) than households with an unvaccinated primary case (66/108, 62%). CONCLUSIONS: Although SARS-CoV-2 infections in vaccinated household contacts were reported in this high transmission setting, full vaccination protected against SARS-CoV-2 infection. These findings further support the protective effect of COVID-19 vaccination and highlight the need for ongoing vaccination among eligible persons. |
Cohort profile: Indian Network of Population-Based Surveillance Platforms for Influenza and Other Respiratory Viruses among the Elderly (INSPIRE).
Krishnan A , Dar L , Amarchand R , Prabhakaran AO , Kumar R , Rajkumar P , Kanungo S , Bhardwaj SD , Choudekar A , Potdar V , Chakrabarti AK , Kumar CG , Parameswaran GG , Dhakad S , Manna B , Choudhary A , Lafond KE , Azziz-Baumgartner E , Saha S . BMJ Open 2021 11 (10) e052473 PURPOSE: We describe here a multicentric community-dwelling cohort of older adults (>60 years of age) established to estimate incidence, study risk factors, healthcare utilisation and economic burden associated with influenza and respiratory syncytial virus (RSV) in India. PARTICIPANTS: The four sites of this cohort are in northern (Ballabgarh), southern (Chennai), eastern (Kolkata) and western (Pune) parts of India. We enrolled 5336 participants across 4220 households and began surveillance in July 2018 for viral respiratory infections with additional participants enrolled annually. Trained field workers collected data about individual-level and household-level risk factors at enrolment and quarterly assessed frailty and grip strength. Trained nurses surveilled weekly to identify acute respiratory infections (ARI) and clinically assessed individuals to diagnose acute lower respiratory infection (ALRI) as per protocol. Nasal and oropharyngeal swabs are collected from all ALRI cases and one-fifth of the other ARI cases for laboratory testing. Cost data of the episode are collected using the WHO approach for estimating the economic burden of seasonal influenza. Handheld tablets with Open Data Kit platform were used for data collection. FINDINGS TO DATE: The attrition of 352 participants due to migration and deaths was offset by enrolling 680 new entrants in the second year. All four sites reported negligible influenza vaccination uptake (0.1%-0.4%), low health insurance coverage (0.4%-22%) and high tobacco use (19%-52%). Ballabgarh had the highest proportion (54.4%) of households in the richest wealth quintile, but reported high solid fuel use (92%). Frailty levels were highest in Kolkata (11.3%) and lowest in Pune (6.8%). The Chennai cohort had highest self-reported morbidity (90.1%). FUTURE PLANS: The findings of this cohort will be used to inform prioritisation of strategies for influenza and RSV control for older adults in India. We also plan to conduct epidemiological studies of SARS-CoV-2 using this platform. |
Remdesivir targets a structurally analogous region of the Ebola virus and SARS-CoV-2 polymerases.
Lo MK , Albariño CG , Perry JK , Chang S , Tchesnokov EP , Guerrero L , Chakrabarti A , Shrivastava-Ranjan P , Chatterjee P , McMullan LK , Martin R , Jordan R , Götte M , Montgomery JM , Nichol ST , Flint M , Porter D , Spiropoulou CF . Proc Natl Acad Sci U S A 2020 117 (43) 26946-26954 Remdesivir is a broad-spectrum antiviral nucleotide prodrug that has been clinically evaluated in Ebola virus patients and recently received emergency use authorization (EUA) for treatment of COVID-19. With approvals from the Federal Select Agent Program and the Centers for Disease Control and Prevention's Institutional Biosecurity Board, we characterized the resistance profile of remdesivir by serially passaging Ebola virus under remdesivir selection; we generated lineages with low-level reduced susceptibility to remdesivir after 35 passages. We found that a single amino acid substitution, F548S, in the Ebola virus polymerase conferred low-level reduced susceptibility to remdesivir. The F548 residue is highly conserved in filoviruses but should be subject to specific surveillance among novel filoviruses, in newly emerging variants in ongoing outbreaks, and also in Ebola virus patients undergoing remdesivir therapy. Homology modeling suggests that the Ebola virus polymerase F548 residue lies in the F-motif of the polymerase active site, a region that was previously identified as susceptible to resistance mutations in coronaviruses. Our data suggest that molecular surveillance of this region of the polymerase in remdesivir-treated COVID-19 patients is also warranted. |
Bridging the knowledge gap on mycoses in Africa; setting up a Pan-African Mycology Working Group
Oladele RO , Akase IE , Fahal A , Govender NP , Honigl M , Gangneux JP , Chiller TM , Denning DW , Cornely OA , Chakrabarti A . Mycoses 2019 63 (3) 244-249 Most African countries have poorly funded and overburdened health systems. Additionally, a high prevalence of HIV in Sub-Saharan Africa contributes to a high burden of opportunistic fungal infections. Data generated by GAFFI from 15 of 57 African countries revealed that an estimated 47 million Africans suffer from fungal diseases, of whom an estimated 1.7 million suffer from a serious fungal infection annually. Almost all African countries lack a surveillance system for fungal infections with the exception of South Africa. South Africa is also the only African country with a national mycology reference laboratory. Across the continent, there is a pervasive picture of inadequate/poor diagnostic capacity, low level of awareness among health care workers and policy makers as well as unavailability and non-accessibility to essential antifungal medications. Recent outreach efforts by the International Society for Human and Animal Mycology (ISHAM) and the European Confederation of Medical Mycology (ECMM) have aimed to increase involvement of African countries and experts in global initiatives such as "One World One Guideline" and also the ECMM Academy. Recently, under the auspices of ISHAM, the African sub-region created a network of mycology experts whose goal is organize and engage African leaders in the field of medical mycology. The aim of this ISHAM Working Group is to facilitate interaction and synergy among regional leaders in order to develop educational programs for capacity building to aid in the diagnosis and care of patients with fungal infections in Africa. The working group will also encourage country initiatives to develop clinical guidelines, to support surveys, and to support the establishment of reference mycology laboratories. |
The Diagnosis of Fungal Neglected Tropical Diseases (Fungal NTDs) and the Role of Investigation and Laboratory Tests: An Expert Consensus Report.
Hay R , Denning DW , Bonifaz A , Queiroz-Telles F , Beer K , Bustamante B , Chakrabarti A , Chavez-Lopez MG , Chiller T , Cornet M , Estrada R , Estrada-Chavez G , Fahal A , Gomez BL , Li R , Mahabeer Y , Mosam A , Soavina Ramarozatovo L , Rakoto Andrianarivelo M , Rapelanoro Rabenja F , van de Sande W , Zijlstra EE . Trop Med Infect Dis 2019 4 (4) The diagnosis of fungal Neglected Tropical Diseases (NTD) is primarily based on initial visual recognition of a suspected case followed by confirmatory laboratory testing, which is often limited to specialized facilities. Although molecular and serodiagnostic tools have advanced, a substantial gap remains between the desirable and the practical in endemic settings. To explore this issue further, we conducted a survey of subject matter experts on the optimal diagnostic methods sufficient to initiate treatment in well-equipped versus basic healthcare settings, as well as optimal sampling methods, for three fungal NTDs: mycetoma, chromoblastomycosis, and sporotrichosis. A survey of 23 centres found consensus on the key role of semi-invasive sampling methods such as biopsy diagnosis as compared with swabs or impression smears, and on the importance of histopathology, direct microscopy, and culture for mycetoma and chromoblastomycosis confirmation in well-equipped laboratories. In basic healthcare settings, direct microscopy combined with clinical signs were reported to be the most useful diagnostic indicators to prompt referral for treatment. The survey identified that the diagnosis of sporotrichosis is the most problematic with poor sensitivity across the most widely available laboratory tests except fungal culture, highlighting the need to improve mycological diagnostic capacity and to develop innovative diagnostic solutions. Fungal microscopy and culture are now recognized as WHO essential diagnostic tests and better training in their application will help improve the situation. For mycetoma and sporotrichosis, in particular, advances in identifying specific marker antigens or genomic sequences may pave the way for new laboratory-based or point-of-care tests, although this is a formidable task given the large number of different organisms that can cause fungal NTDs. |
Characterisation of infectious Ebola virus from the ongoing outbreak to guide response activities in the Democratic Republic of the Congo: a phylogenetic and in vitro analysis.
McMullan LK , Flint M , Chakrabarti A , Guerrero L , Lo MK , Porter D , Nichol ST , Spiropoulou CF , Albarino C . Lancet Infect Dis 2019 19 (9) 1023-1032 BACKGROUND: The ongoing Ebola virus outbreak in the Ituri and North Kivu Provinces of the Democratic Republic of the Congo, which began in July, 2018, is the second largest ever recorded. Despite civil unrest, outbreak control measures and the administration of experimental therapies and a vaccine have been initiated. The aim of this study was to test the efficacy of candidate therapies and diagnostic tests with the outbreak strain Ituri Ebola virus. Lacking a virus isolate from this outbreak, a recombinant Ituri Ebola virus was compared with a similarly engineered Makona virus from the 2013-16 outbreak. METHODS: Using Ebola virus sequences provided by organisations in DR Congo and a reverse genetics system, we generated an authentic Ebola virus from the ongoing outbreak in Ituri and North Kivu provinces. To relate this virus to other Ebola viruses in DR Congo, we did a phylogenetic analysis of representative complete Ebola virus genome sequences from previous outbreaks. We evaluated experimental therapies being tested in clinical trials in DR Congo, including remdesivir and ZMapp monoclonal antibodies, for their ability to inhibit the growth of infectious Ituri Ebola virus in cell culture. We also tested diagnostic assays for detection of the Ituri Ebola virus sequence. FINDINGS: The phylogenetic analysis of whole-genome sequences from each Ebola virus outbreak suggests there are at least two Ebola virus strains in DR Congo, which have independently crossed into the human population. The Ituri Ebola strain initially grew slower than the Makona strain, yet reached similar mean yields of 3 x 10(7) 50% tissue culture infectious dose by 72 h infection in Huh-7 cells. Ituri Ebola virus was similar to Makona in its susceptibility to inhibition by remdesivir and to neutralisation by monoclonal antibodies from ZMapp and other monoclonal antibodies. Remdesivir inhibited Ituri Ebola virus at a 50% effective concentration (EC50) of 12nM (with a selectivity index of 303) and Makona Ebola virus at 13nM (with a selectivity index of 279). The Zmapp monoclonal antibodies 2G4 and 4G7 neutralised Ituri Ebola virus with a mean EC50 of 0.24 mug/mL and 0.48 mug/mL, and Makona Ebola virus with a mean EC50 of 0.45 mug/mL and 0.2 mug/mL. The Xpert Ebola and US Centers for Disease Control and Prevention real-time RT-qPCR diagnostic assays detected Ituri and Makona Ebola virus sequences with similar sensitivities and efficiencies, despite primer site binding mismatches in the Ituri Ebola virus. INTERPRETATION: Our findings provide a rationale for the continued testing of investigational therapies, confirm the effectiveness of the diagnostic assays used in the region, and establish a paradigm for the use of reverse genetics to inform response activities in an outbreak. FUNDING: US Centers for Disease Control and Prevention. |
Essential in vitro diagnostics for advanced HIV and serious fungal diseases: international experts' consensus recommendations
Bongomin F , Govender NP , Chakrabarti A , Robert-Gangneux F , Boulware DR , Zafar A , Oladele RO , Richardson MD , Gangneux JP , Alastruey-Izquierdo A , Bazira J , Boyles TH , Sarcarlal J , Nacher M , Obayashi T , Worodria W , Pasqualotto AC , Meya DB , Cheng B , Sriruttan C , Muzoora C , Kambugu A , Rodriguez Tudela JL , Jordan A , Chiller TM , Denning DW . Eur J Clin Microbiol Infect Dis 2019 38 (9) 1581-1584 An accurate, timely diagnosis is the cornerstone of good medical practice. For opportunistic fungal infections in AIDS and other invasive mycoses, this is dependent on the availability of and accessibility to the relevant diagnostic tests. A call for a model List of Essential In Vitro Diagnostics (EDL)—“listed tests that should be reasonably available for people who need them, whether in the form of point-of-care tests in physicians’ offices and pharmacies or as high-complexity tests in reference laboratories”—has been published [1]. In addition to better medical practice, other potential benefits of an EDL include clarification of priorities for policy makers, setting common goals for laboratory testing, improved healthcare delivery and overall better patient outcomes [1]. In the context of extensive antimicrobial resistance (AMR), a reduction in empiricism with more accurate diagnosis will play a key role in AMR control [2]. |
Prognostic factors in 264 adults with invasive Scedosporium spp. and Lomentospora prolificans infection reported in the literature and FungiScope(R)
Seidel D , Meissner A , Lackner M , Piepenbrock E , Salmanton-Garcia J , Stecher M , Mellinghoff S , Hamprecht A , Duran Graeff L , Kohler P , Cheng MP , Denis J , Chedotal I , Chander J , Pakstis DL , Los-Arcos I , Slavin M , Montagna MT , Caggiano G , Mares M , Trauth J , Aurbach U , Vehreschild Mjgt , Vehreschild JJ , Duarte RF , Herbrecht R , Wisplinghoff H , Cornely OA , Bachmann B , Borchert K , Burchardt A , Chakrabarti A , Christopeit M , Fasih N , Hekmat K , Hernandez Ruperez B , Kemmerling B , Kessel J , Jyoti Kindo A , Klimko N , Krause R , Lass-Florl C , Levesque E , Lockhart S , Steinmann J , Maritati A , Markiefka B , Martin Gomez MT , Meis J , Oksi J , Pagano L , Ramos Martinez A , Reischies F , Soler Palacin P , Vermeulen E . Crit Rev Microbiol 2019 45 (1) 1-21 Invasive Scedosporium spp. and Lomentospora prolificans infections are an emerging threat in immunocompromised and occasionally in healthy hosts. Scedosporium spp. is intrinsically resistant to most, L. prolificans to all the antifungal drugs currently approved, raising concerns about appropriate treatment decisions. High mortality rates of up to 90% underline the need for comprehensive diagnostic workup and even more for new, effective antifungal drugs to improve patient outcome. For a comprehensive analysis, we identified cases of severe Scedosporium spp. and L. prolificans infections from the literature diagnosed in 2000 or later and the FungiScope((R)) registry. For 208 Scedosporium spp. infections solid organ transplantation (n = 58, 27.9%) and for 56 L. prolificans infection underlying malignancy (n = 28, 50.0%) were the most prevalent risk factors. L. prolificans infections frequently presented as fungemia (n = 26, 46.4% versus n = 12, 5.8% for Scedosporium spp.). Malignancy, fungemia, CNS and lung involvement predicted worse outcome for scedosporiosis and lomentosporiosis. Patients treated with voriconazole had a better overall outcome in both groups compared to treatment with amphotericin B formulations. This review discusses the epidemiology, prognostic factors, pathogen susceptibility to approved and investigational antifungals, and treatment strategies of severe infections caused by Scedosporium spp. and L. prolificans. |
Antibody-mediated virus neutralization is not a universal mechanism of Marburg, Ebola or Sosuga virus clearance in Egyptian rousette bats
Schuh AJ , Amman BR , Sealy TK , Kainulainen MH , Chakrabarti AK , Guerrero LW , Nichol ST , Albarino CG , Towner JS . J Infect Dis 2018 219 (11) 1716-1721 Although bats are increasingly being recognized as natural reservoir hosts of emerging zoonotic viruses, little is known about how they control and clear virus infection in the absence of clinical disease. Here, we test >50 convalescent sera from Egyptian rousette bats (ERBs) experimentally primed or prime-boosted with Marburg virus, Ebola virus or Sosuga virus for the presence of virus-specific neutralizing antibodies using infectious reporter viruses. After serum neutralization testing, we conclude that antibody-mediated virus neutralization does not contribute significantly to the control and clearance of Marburg virus, Ebola virus or Sosuga virus infection in ERBs. |
Complete Genome Sequences of Monongahela Hantavirus from Pennsylvania, USA.
Albarino CG , Guerrero LW , Chakrabarti AK , Rollin PE , Nichol ST . Microbiol Resour Announc 2018 7 (11) Monongahela hantavirus was first identified in deer mice and was later found responsible for hantavirus pulmonary syndrome cases in Pennsylvania and West Virginia in the United States. Here, we report the complete sequences of Monongahela virus S, M, and L genomic segments obtained from a fatal clinical case reported in 1997. Copyright © 2018 Microbiology Resource Announcements. All rights reserved. |
The S Genome Segment Is Sufficient to Maintain Pathogenicity in Intra-Clade Lassa Virus Reassortants in a Guinea Pig Model.
Welch SR , Scholte FEM , Albarino CG , Kainulainen MH , Coleman-McCray JD , Guerrero LW , Chakrabarti AK , Klena JD , Nichol ST , Spengler JR , Spiropoulou CF . Front Cell Infect Microbiol 2018 8 240 Genome reassortment in Lassa virus (LASV) has been reported in nature, but phenotypic consequences of this phenomenon are not well described. Here we characterize, both in vitro and in vivo, reassortment between 2 LASV strains: the prototypic 1976 Josiah strain and a more recently isolated 2015 Liberian strain. In vitro analysis showed that although cis- and trans-acting elements of viral RNA synthesis were compatible between strains, reassortants demonstrated different levels of viral replication. These differences were also apparent in vivo, as reassortants varied in pathogenicity in the guinea pig model of LASV infection. The reassortant variant containing the Josiah S segment retained the virulence of the parental Josiah strain, but the reassortant variant containing the S segment of the Liberian isolate was highly attenuated compared to both parental strains. Contrary to observations in reassortants between LASV and other arenavirus species, which suggest that L segment-encoded factors are responsible for virulence, these studies highlight a role for S segment-encoded virulence factors in disease, and also suggest that inefficient interactions between proteins of heterologous strains may limit the prevalence of reassortant LASV variants in nature. |
Transcriptional analysis of viral mRNAs reveals common transcription patterns in cells infected by five different filoviruses.
Albarino CG , Wiggleton Guerrero L , Chakrabarti AK , Nichol ST . PLoS One 2018 13 (8) e0201827 Filoviruses are notorious viral pathogens responsible for high-consequence diseases in humans and non-human primates. Transcription of filovirus mRNA shares several common features with transcription in other non-segmented negative-strand viruses, including differential expression of genes located across the viral genome. Transcriptional patterns of Ebola virus (EBOV) and Marburg virus (MARV) have been previously described using traditional, laborious methods, such as northern blots and in vivo labeling of viral mRNAs. More recently, however, the availability of the next generation sequencing (NGS) technology has offered a more straightforward approach to assess transcriptional patterns. In this report, we analyzed the transcription patterns of four ebolaviruses-EBOV, Sudan (SUDV), Bundibugyo (BDBV), and Reston (RESTV) viruses-in two different cell lines using standard NGS library preparation and sequencing protocols. In agreement with previous reports mainly focused on EBOV and MARV, the remaining filoviruses used in this study also showed a consistent transcription pattern, with only minor variations between the different viruses. We have also analyzed the proportions of the three mRNAs transcribed from the GP gene, which are characteristic of the genus Ebolavirus and encode the glycoprotein (GP), the soluble GP (sGP), and the small soluble GP (ssGP). In addition, we used NGS methodology to analyze the transcription pattern of two previously described recombinant MARV. This analysis allowed us to correct our construction design, and to make an improved version of the original MARV expressing reporter genes. |
Development of a reverse genetics system for Sosuga virus allows rapid screening of antiviral compounds.
Welch SR , Chakrabarti AK , Wiggleton Guerrero L , Jenks HM , Lo MK , Nichol ST , Spiropoulou CF , Albarino CG . PLoS Negl Trop Dis 2018 12 (3) e0006326 Sosuga virus (SOSV) is a recently discovered zoonotic paramyxovirus isolated from a single human case in 2012; it has been ecologically and epidemiologically associated with transmission by the Egyptian rousette bat (Rousettus aegyptiacus). Bats have long been recognized as sources of novel zoonotic pathogens, including highly lethal paramyxoviruses like Nipah virus (NiV) and Hendra virus (HeV). The ability of SOSV to cause severe human disease supports the need for studies on SOSV pathogenesis to better understand the potential impact of this virus and to identify effective treatments. Here we describe a reverse genetics system for SOSV comprising a minigenome-based assay and a replication-competent infectious recombinant reporter SOSV that expresses the fluorescent protein ZsGreen1 in infected cells. First, we used the minigenome assay to rapidly screen for compounds inhibiting SOSV replication at biosafety level 2 (BSL-2). The antiviral activity of candidate compounds was then tested against authentic viral replication using the reporter SOSV at BSL-3. We identified several compounds with anti-SOSV activity, several of which also inhibit NiV and HeV. Alongside its utility in screening for potential SOSV therapeutics, the reverse genetics system described here is a powerful tool for analyzing mechanisms of SOSV pathogenesis, which will facilitate our understanding of how to combat the potential public health threats posed by emerging bat-borne paramyxoviruses. |
Insights into Reston virus spillovers and adaption from virus whole genome sequences.
Albarino CG , Wiggleton Guerrero L , Jenks HM , Chakrabarti AK , Ksiazek TG , Rollin PE , Nichol ST . PLoS One 2017 12 (5) e0178224 Reston virus (family Filoviridae) is unique among the viruses of the Ebolavirus genus in that it is considered non-pathogenic in humans, in contrast to the other members which are highly virulent. The virus has however, been associated with several outbreaks of highly lethal hemorrhagic fever in non-human primates (NHPs), specifically cynomolgus monkeys (Macaca fascicularis) originating in the Philippines. In addition, Reston virus has been isolated from domestic pigs in the Philippines. To better understand virus spillover events and potential adaption to new hosts, the whole genome sequences of representative Reston virus isolates were obtained using a next generation sequencing (NGS) approach and comparative genomic analysis and virus fitness analyses were performed. Nine virus genome sequences were completed for novel and previously described isolates obtained from a variety of hosts including a human case, non-human primates and pigs. Results of phylogenetic analysis of the sequence differences are consistent with multiple independent introductions of RESTV from a still unknown natural reservoir into non-human primates and swine farming operations. No consistent virus genetic markers were found specific for viruses associated with primate or pig infections, but similar to what had been seen with some Ebola viruses detected in the large Western Africa outbreak in 2014-2016, a truncated version of VP30 was identified in a subgroup of Reston viruses obtained from an outbreak in pigs 2008-2009. Finally, the genetic comparison of two closely related viruses, one isolated from a human case and one from an NHP, showed amino acid differences in the viral polymerase and detectable differences were found in competitive growth assays on human and NHP cell lines. |
Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study
Shrivastava A , Kumar A , Thomas JD , Laserson KF , Bhushan G , Carter MD , Chhabra M , Mittal V , Khare S , Sejvar JJ , Dwivedi M , Isenberg SL , Johnson R , Pirkle JL , Sharer JD , Hall PL , Yadav R , Velayudhan A , Papanna M , Singh P , Somashekar D , Pradhan A , Goel K , Pandey R , Kumar M , Kumar S , Chakrabarti A , Sivaperumal P , Kumar AR , Schier JG , Chang A , Graham LA , Mathews TP , Johnson D , Valentin L , Caldwell KL , Jarrett JM , Harden LA , Takeoka GR , Tong S , Queen K , Paden C , Whitney A , Haberling DL , Singh R , Singh RS , Earhart KC , Dhariwal AC , Chauhan LS , Venkatesh S , Srikantiah P . Lancet Glob Health 2017 5 (4) e458-e466 BACKGROUND: Outbreaks of unexplained illness frequently remain under-investigated. In India, outbreaks of an acute neurological illness with high mortality among children occur annually in Muzaffarpur, the country's largest litchi cultivation region. In 2014, we aimed to investigate the cause and risk factors for this illness. METHODS: In this hospital-based surveillance and nested age-matched case-control study, we did laboratory investigations to assess potential infectious and non-infectious causes of this acute neurological illness. Cases were children aged 15 years or younger who were admitted to two hospitals in Muzaffarpur with new-onset seizures or altered sensorium. Age-matched controls were residents of Muzaffarpur who were admitted to the same two hospitals for a non-neurologic illness within seven days of the date of admission of the case. Clinical specimens (blood, cerebrospinal fluid, and urine) and environmental specimens (litchis) were tested for evidence of infectious pathogens, pesticides, toxic metals, and other non-infectious causes, including presence of hypoglycin A or methylenecyclopropylglycine (MCPG), naturally-occurring fruit-based toxins that cause hypoglycaemia and metabolic derangement. Matched and unmatched (controlling for age) bivariate analyses were done and risk factors for illness were expressed as matched odds ratios and odds ratios (unmatched analyses). FINDINGS: Between May 26, and July 17, 2014, 390 patients meeting the case definition were admitted to the two referral hospitals in Muzaffarpur, of whom 122 (31%) died. On admission, 204 (62%) of 327 had blood glucose concentration of 70 mg/dL or less. 104 cases were compared with 104 age-matched hospital controls. Litchi consumption (matched odds ratio [mOR] 9.6 [95% CI 3.6 - 24]) and absence of an evening meal (2.2 [1.2-4.3]) in the 24 h preceding illness onset were associated with illness. The absence of an evening meal significantly modified the effect of eating litchis on illness (odds ratio [OR] 7.8 [95% CI 3.3-18.8], without evening meal; OR 3.6 [1.1-11.1] with an evening meal). Tests for infectious agents and pesticides were negative. Metabolites of hypoglycin A, MCPG, or both were detected in 48 [66%] of 73 urine specimens from case-patients and none from 15 controls; 72 (90%) of 80 case-patient specimens had abnormal plasma acylcarnitine profiles, consistent with severe disruption of fatty acid metabolism. In 36 litchi arils tested from Muzaffarpur, hypoglycin A concentrations ranged from 12.4 mug/g to 152.0 mug/g and MCPG ranged from 44.9 mug/g to 220.0 mug/g. INTERPRETATION: Our investigation suggests an outbreak of acute encephalopathy in Muzaffarpur associated with both hypoglycin A and MCPG toxicity. To prevent illness and reduce mortality in the region, we recommended minimising litchi consumption, ensuring receipt of an evening meal and implementing rapid glucose correction for suspected illness. A comprehensive investigative approach in Muzaffarpur led to timely public health recommendations, underscoring the importance of using systematic methods in other unexplained illness outbreaks. FUNDING: US Centers for Disease Control and Prevention. |
25-hydroxycholesterol inhibition of Lassa virus infection through aberrant GP1 glycosylation
Shrivastava-Ranjan P , Bergeron E , Chakrabarti AK , Albarino CG , Flint M , Nichol ST , Spiropoulou CF . mBio 2016 7 (6) Lassa virus (LASV) infection is a major public health concern due to high fatality rates and limited effective treatment. The interferon-stimulated gene cholesterol 25-hydroxylase (CH25H) encodes an enzyme that catalyzes the production of 25-hydroxycholesterol (25HC). 25HC is involved in regulating cholesterol biosynthesis and has recently been identified as a potent antiviral targeting enveloped virus entry. Here, we show a previously unrecognized role of CH25H in inhibiting LASV glycoprotein glycosylation and the production of infectious virus. Overexpression of CH25H or treatment with 25HC decreased LASV G1 glycoprotein N-glycan maturation and reduced the production of infectious LASV. Depletion of endogenous CH25H using small interfering RNA (siRNA) enhanced the levels of fully glycosylated G1 and increased infectious LASV production. Finally, LASV particles produced from 25HC-treated cells were found to be less infectious, to incorporate aberrantly glycosylated GP1 species, and to be defective in binding alpha-dystroglycan, an attachment and entry receptor. Our findings identify a novel role for CH25H in controlling LASV propagation and indicate that manipulation of the expression of CH25H or the administration of 25HC may be a useful anti-LASV therapy. IMPORTANCE: Lassa fever is an acute viral hemorrhagic fever in humans caused by Lassa virus (LASV). No vaccine for LASV is currently available. Treatment is limited to the administration of ribavirin, which is only effective when given early in the course of illness. Cholesterol 25-hydroxylase (CH25H) is a recently identified interferon-stimulated gene (ISG); it encodes an enzyme that catalyzes the production of 25-hydroxycholesterol (25HC), which inhibits several viruses. Here, we identify a novel antiviral mechanism of 25HC that is dependent on inhibiting the glycosylation of Lassa virus (LASV) glycoprotein and reducing the infectivity of LASV as a means of suppressing viral replication. Since N-linked glycosylation is a critical feature of other enveloped-virus glycoproteins, 25HC may be a broad inhibitor of virus infectivity. |
Novel activities by ebolavirus and marburgvirus interferon antagonists revealed using a standardized in vitro reporter system.
Guito JC , Albarino CG , Chakrabarti AK , Towner JS . Virology 2016 501 147-165 Filoviruses are highly lethal in humans and nonhuman primates, likely due to potent antagonism of host interferon (IFN) responses early in infection. Filoviral protein VP35 is implicated as the major IFN induction antagonist, while Ebola virus (EBOV) VP24 or Marburg virus (MARV) VP40 are known to block downstream IFN signaling. Despite progress elucidating EBOV and MARV antagonist function, those for most other filoviruses, including Reston (RESTV), Sudan (SUDV), Tai Forest (TAFV), Bundibugyo (BDBV) and Ravn (RAVV) viruses, remain largely neglected. Thus, using standardized vectors and reporter assays, we characterized activities by each IFN antagonist from all known ebolavirus and marburgvirus species side-by-side. We uncover noncanonical suppression of IFN induction by ebolavirus VP24, differing potencies by MARV and RAVV proteins, and intriguingly, weaker antagonism by VP24 of RESTV. These underlying molecular explanations for differential virulence in humans could guide future investigations of more-neglected filoviruses as well as treatment and vaccine studies. |
Lassa and Ebola virus inhibitors identified using minigenome and recombinant virus reporter systems.
Welch SR , Guerrero LW , Chakrabarti AK , McMullan LK , Flint M , Bluemling GR , Painter GR , Nichol ST , Spiropoulou CF , Albarino CG . Antiviral Res 2016 136 9-18 Lassa virus (LASV) and Ebola virus (EBOV) infections are important global health issues resulting in significant morbidity and mortality. While several promising drug and vaccine trials for EBOV are ongoing, options for LASV infection are currently limited to ribavirin treatment. A major factor impeding the development of antiviral compounds to treat these infections is the need to manipulate the virus under BSL-4 containment, limiting research to a few institutes worldwide. Here we describe the development of a novel LASV minigenome assay based on the ambisense LASV S segment genome, with authentic terminal untranslated regions flanking a ZsGreen (ZsG) fluorescent reporter protein and a Gaussia princeps luciferase (gLuc) reporter gene. This assay, along with a similar previously established EBOV minigenome, was optimized for high-throughput screening (HTS) of potential antiviral compounds under BSL-2 containment. In addition, we rescued a recombinant LASV expressing ZsG, which, in conjunction with a recombinant EBOV reporter virus, was used to confirm any potential antiviral hits in vitro. Combining an initial screen to identify potential antiviral compounds at BSL-2 containment before progressing to HTS with infectious virus will reduce the amount of expensive and technically challenging BSL-4 containment research. Using these assays, we identified 6-azauridine as having anti-LASV activity, and demonstrated its anti-EBOV activity in human cells. We further identified 2'-deoxy-2'-fluorocytidine as having potent anti-LASV activity, with an EC50 value 10 times lower than that of ribavirin. |
Ebola Virus Disease Diagnostics, Sierra Leone: Analysis of Real-time Reverse Transcription-Polymerase Chain Reaction Values for Clinical Blood and Oral Swab Specimens.
Erickson BR , Sealy TK , Flietstra T , Morgan L , Kargbo B , Matt-Lebby VE , Gibbons A , Chakrabarti AK , Graziano J , Presser L , Flint M , Bird BH , Brown S , Klena JD , Blau DM , Brault AC , Belser JA , Salzer JS , Schuh AJ , Lo M , Zivcec M , Priestley RA , Pyle M , Goodman C , Bearden S , Amman BR , Basile A , Bergeron E , Bowen MD , Dodd KA , Freeman MM , McMullan LK , Paddock CD , Russell BJ , Sanchez AJ , Towner JS , Wang D , Zemtsova GE , Stoddard RA , Turnsek M , Guerrero LW , Emery SL , Stovall J , Kainulainen MH , Perniciaro JL , Mijatovic-Rustempasic S , Shakirova G , Winter J , Sexton C , Liu F , Slater K , Anderson R , Andersen L , Chiang CF , Tzeng WP , Crowe SJ , Maenner MJ , Spiropoulou CF , Nichol ST , Stroher U . J Infect Dis 2016 214 S258-S262 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. |
Virus fitness differences observed between two naturally occurring isolates of Ebola virus Makona variant using a reverse genetics approach.
Albarino CG , Guerrero LW , Chakrabarti AK , Kainulainen MH , Whitmer SL , Welch SR , Nichol ST . Virology 2016 496 237-243 During the large outbreak of Ebola virus disease that occurred in Western Africa from late 2013 to early 2016, several hundred Ebola virus (EBOV) genomes have been sequenced and the virus genetic drift analyzed. In a previous report, we described an efficient reverse genetics system designed to generate recombinant EBOV based on a Makona variant isolate obtained in 2014. Using this system, we characterized the replication and fitness of 2 isolates of the Makona variant. These virus isolates are nearly identical at the genetic level, but have single amino acid differences in the VP30 and L proteins. The potential effects of these differences were tested using minigenomes and recombinant viruses. The results obtained with this approach are consistent with the role of VP30 and L as components of the EBOV RNA replication machinery. Moreover, the 2 isolates exhibited clear fitness differences in competitive growth assays. |
Humanized mouse model of Ebola virus disease mimics immune responses in human disease
Bird BH , Spengler JR , Chakrabarti AK , Khristova ML , Sealy TK , Coleman-McCray JD , Martin BE , Dodd KA , Goldsmith CS , Sanders J , Zaki SR , Nichol ST , Spiropoulou CF . J Infect Dis 2015 213 (5) 703-11 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 cause disease in immunocompetent adult rodents without adaptation. Here we describe EVD in humanized BLT mice (hu-BLT) engrafted with human immune cells. 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 histopathology similar to that shown in the limited human post-mortem data available. A dose- and donor- dependent clinical course was observed in hu-BLT 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 non-engrafted 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 offer an alternative animal model for EVD pathogenesis studies and therapeutic screening. |
Utility of oral swab sampling for Ebola virus detection in Guinea pig model
Spengler JR , Chakrabarti AK , Coleman-McCray JD , Martin BE , Nichol ST , Spiropoulou CF , Bird BH . Emerg Infect Dis 2015 21 (10) 1816-9 To determine the utility of oral swabs for diagnosing infection with Ebola virus, we used a guinea pig model and obtained daily antemortem and postmortem swab samples. According to quantitative reverse transcription PCR analysis, the diagnostic value was poor for antemortem swab samples but excellent for postmortem samples. |
RIG-I mediates an antiviral response to Crimean-Congo hemorrhagic fever virus.
Spengler JR , Patel JR , Chakrabarti AK , Zivcec M , Garcia-Sastre A , Spiropoulou CF , Bergeron E . J Virol 2015 89 (20) 10219-29 In the cytoplasm, the retinoic acid-inducible gene I (RIG-I) senses the RNA genomes of several RNA viruses. RIG-I binds to viral RNA, eliciting an antiviral response via the cellular adaptor MAVS. Crimean-Congo hemorrhagic fever virus (CCHFV), a negative sense RNA virus with a 5' -monophosphorylated genome, is a highly pathogenic zoonotic agent with significant public health and clinical implications. We found that, during CCHFV infection, RIG-I mediated a type-I interferon (IFN) response via MAVS. Interfering with RIG-I signaling reduced IFN production and IFN-stimulated gene expression, and increased viral replication. Immunostimulatory RNA was isolated from CCHFV-infected cells and from virion preparations, and RIG-I co-immunoprecipitation of infected cell lysates isolated immunostimulatory CCHFV RNA. This report serves as the first description of a pattern recognition receptor for CCHFV and highlights a critical signaling pathway in the antiviral response to CCHFV. IMPORTANCE: Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus with significant public health and clinical impact. In order for cells to respond to virus infection, they must recognize the virus as foreign and initiate antiviral signaling. To date, the receptors involved in recognition of CCHFV are not known. Herein we investigate and identify retinoic acid-inducible gene I (RIG-I) as a receptor involved in initiating an antiviral response to CCHFV. This receptor was initially not expected to play a role in CCHFV recognition because of characteristics of the viral genome. These findings are important in understanding the antiviral response to CCHFV and support continued investigation into the spectrum of potential viruses recognized by RIG-I. |
Ebola virus diagnostics: the US Centers for Disease Control and Prevention laboratory in Sierra Leone, August 2014 to March 2015
Flint M , Goodman CH , Bearden S , Blau DM , Amman BR , Basile AJ , Belser JA , Bergeron E , Bowen MD , Brault AC , Campbell S , Chakrabarti AK , Dodd KA , Erickson BR , Freeman MM , Gibbons A , Guerrero LW , Klena JD , Lash RR , Lo MK , McMullan LK , Momoh G , Massally JL , Goba A , Paddock CD , Priestley RA , Pyle M , Rayfield M , Russell BJ , Salzer JS , Sanchez AJ , Schuh AJ , Sealy TK , Steinau M , Stoddard RA , Taboy C , Turnsek M , Wang D , Zemtsova GE , Zivcec M , Spiropoulou CF , Stroher U , Towner JS , Nichol ST , Bird BH . J Infect Dis 2015 212 Suppl 2 S350-8 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. |
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