Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-30 (of 40 Records) |
Query Trace: Hutson CL [original query] |
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Ten years of high-consequence pathogens-research gains, readiness gaps, and future goals
McQuiston JH , Montgomery JM , Hutson CL . Emerg Infect Dis 2024 30 (4) 800-802 |
Investigation of an mpox outbreak affecting many vaccinated persons in Chicago, IL-March 2023-June 2023
Faherty EAG , Holly T , Ogale YP , Spencer H , Becht AM , Crisler G , Wasz M , Stonehouse P , Barbian HJ , Zelinski C , Kittner A , Foulkes D , Anderson KW , Evans T , Nicolae L , Staton A , Hardnett C , Townsend MB , Carson WC , Panayampalli SS , Hutson CL , Gigante CM , Quilter LAS , Gorman S , Borah B , Black SR , Pacilli M , Kern D , Kerins J , McCollum AM , Rao AK , Tabidze I . Clin Infect Dis 2024 BACKGROUND: After months of few mpox cases, an increased number of cases were reported in Chicago during May 2023; predominantly among fully vaccinated patients. We investigated the outbreak scope, differences between vaccinated and unvaccinated patients, and hypotheses for monkeypox virus (MPXV) infection after vaccination. METHODS: We interviewed patients and reviewed medical records to assess demographic, behavioral, and clinical characteristics, mpox vaccine status, and vaccine administration routes. We evaluated serum antibody levels after infection and compared patient viral genomes with MPXV sequences in available databases. We discussed potential vaccine compromise with partners who manufactured, handled, and administered vaccine associated with breakthrough infections. RESULTS: During March 18-June 27, 2023, we identified 49 mpox cases; 57% of these mpox patients were fully vaccinated (FV). FV patients received both JYNNEOS doses subcutaneously (57%), intradermally (7%), or via heterologous administration (36%). FV patients had more median sex partners (3, IQR=1-4) versus not fully vaccinated (NFV) patients (1, IQR=1-2). Thirty-six of 37 sequenced specimens belonged to lineage B.1.20 of clade IIb MPXV, which did not demonstrate any amino acid changes relative to B.1, the predominant lineage from May 2022. Vaccinated patients demonstrated expected humoral antibody responses; none were hospitalized. No vaccine storage excursions were identified. Approximately 63% of people at risk for mpox in Chicago were FV during this period. CONCLUSIONS: Our investigation indicated cases were likely due to frequent behaviors associated with mpox transmission, even with relatively high vaccine effectiveness and vaccine coverage. Cases after vaccination might occur in similar populations. |
Pathology and monkeypox virus localization in tissues from immunocompromised patients with severe or fatal mpox
Ritter JM , Martines RB , Bhatnagar J , Rao AK , Villalba JA , Silva-Flannery L , Lee E , Bullock HA , Hutson CL , Cederroth T , Harris CK , Hord K , Xu Y , Brown CA , Guccione JP , Miller M , Paddock CD , Reagan-Steiner S . J Infect Dis 2024 BACKGROUND: Pathology and monkeypox virus (MPXV) tissue tropism in severe and fatal human mpox is not thoroughly described but can help elucidate the disease pathogenesis and the role of coinfections in immunocompromised patients. METHODS: We analyzed biopsy and autopsy tissues from 22 patients with severe or fatal outcomes to characterize pathology and viral antigen and DNA distribution in tissues by immunohistochemistry and in situ hybridization. Tissue-based testing for coinfections was also performed. RESULTS: Mucocutaneous lesions showed necrotizing and proliferative epithelial changes. Deceased patients with autopsy tissues evaluated had digestive tract lesions, and half had systemic tissue necrosis with thrombotic vasculopathy in lymphoid tissues, lung, or other solid organs. Half also had bronchopneumonia, and one-third had acute lung injury. All cases had MPXV antigen and DNA detected in tissues. Coinfections were identified in 5/16 (31%) biopsy and 4/6 (67%) autopsy cases. DISCUSSION: Severe mpox in immunocompromised patients is characterized by extensive viral infection of tissues and viremic dissemination that can progress despite available therapeutics. Digestive tract and lung involvement are common and associated with prominent histopathological and clinical manifestations. Coinfections may complicate mpox diagnosis and treatment. Significant viral DNA (likely correlating to infectious virus) in tissues necessitates enhanced biosafety measures in healthcare and autopsy settings. |
Tecovirimat resistance in Mpox patients, United States, 2022-2023
Smith TG , Gigante CM , Wynn NT , Matheny A , Davidson W , Yang Y , Condori RE , O'Connell K , Kovar L , Williams TL , Yu YC , Petersen BW , Baird N , Lowe D , Li Y , Satheshkumar PS , Hutson CL . Emerg Infect Dis 2023 29 (12) 2426-2432 During the 2022 multinational outbreak of monkeypox virus (MPXV) infection, the antiviral drug tecovirimat (TPOXX; SIGA Technologies, Inc., https://www.siga.com) was deployed in the United States on a large scale for the first time. The MPXV F13L gene homologue encodes the target of tecovirimat, and single amino acid changes in F13 are known to cause resistance to tecovirimat. Genomic sequencing identified 11 mutations previously reported to cause resistance, along with 13 novel mutations. Resistant phenotype was determined using a viral cytopathic effect assay. We tested 124 isolates from 68 patients; 96 isolates from 46 patients were found to have a resistant phenotype. Most resistant isolates were associated with severely immunocompromised mpox patients on multiple courses of tecovirimat treatment, whereas most isolates identified by routine surveillance of patients not treated with tecovirimat remained sensitive. The frequency of resistant viruses remains relatively low (<1%) compared with the total number of patients treated with tecovirimat. |
Prevalence of undiagnosed monkeypox virus infections during global mpox outbreak, United States, June-September 2022
Minhaj FS , Singh V , Cohen SE , Townsend M , Scott H , Szumowski J , Hare CB , Upadhyay P , Reddy J , Alexander B , Baird N , Navarra T , Priyamvada L , Wynn N , Carson WC , Odafe S , Guagliardo SAJ , Sims E , Rao AK , Satheshkumar PS , Weidle PJ , Hutson CL . Emerg Infect Dis 2023 29 (11) 2307-2314 Since May 2022, mpox has been identified in 108 countries without endemic disease; most cases have been in gay, bisexual, or other men who have sex with men. To determine number of missed cases, we conducted 2 studies during June-September 2022: a prospective serologic survey detecting orthopoxvirus antibodies among men who have sex with men in San Francisco, California, and a retrospective monkeypox virus PCR testing of swab specimens submitted for other infectious disease testing among all patients across the United States. The serosurvey of 225 participants (median age 34 years) detected 18 (8.0%) who were orthopoxvirus IgG positive and 3 (1.3%) who were also orthopoxvirus IgM positive. The retrospective PCR study of 1,196 patients (median age 30 years; 54.8% male) detected 67 (5.6%) specimens positive for monkeypox virus. There are likely few undiagnosed cases of mpox in regions where sexual healthcare is accessible and patient and clinician awareness about mpox is increased. |
How the orthodox features of orthopoxviruses led to an unorthodox Mpox outbreak: What we've learned, and what we still need to understand
Brooks JT , Reynolds MG , Torrone E , McCollum A , Spicknall IH , Gigante CM , Li Y , Satheshkumar PS , Quilter LAS , Rao AK , O'Shea J , Guagliardo SAJ , Townsend M , Hutson CL . J Infect Dis 2023 Orthopoxviruses are complex, large-genome DNA viruses that have repeatedly confounded expectations in terms of the clinical illness they cause and their patterns of spread. Monkeypox virus (MPXV) was originally characterized during outbreaks among captive primates in the late 1950's. Human disease (mpox) has been observed since the 1970's and inter-human spread has largely been associated with non-sexual, close physical contact in endemic areas of west and central Africa. In May 2022, a focus of Clade IIb MPXV transmission was detected, spreading largely by sexual contact through international networks of gay, bisexual, and other men who have sex with men. Despite decades of preparedness for the potential biothreat risk posed by smallpox, the outbreak grew in both size and geographic scope, testing the strength of smallpox preparedness tools and public health science alike. In this article we consider what was known about mpox prior to the 2022 outbreak, what we have learned about mpox and Clade IIb virus during the outbreak, and what outbreak response actions and continued research are needed to ensure the global public health community is equipped to detect and halt the further spread of this disease threat. We focus on how epidemiologic characterization and investigation together with laboratory studies have advanced our understanding of the transmission and pathogenesis of mpox, and describe what work remains to be done to optimize diagnostics, therapeutics, and vaccines. Persistent health inequities challenge our capacity to fully eliminate circulation of the 2022 outbreak strain of MPXV currently in the United States. |
Community spread of a human monkeypox virus variant with a tecovirimat resistance-associated mutation
Garrigues JM , Hemarajata P , Espinosa A , Hacker JK , Wynn NT , Smith TG , Gigante CM , Davidson W , Vega J , Edmondson H , Karan A , Marutani AN , Kim M , Terashita D , Balter SE , Hutson CL , Green NM . Antimicrob Agents Chemother 2023 67 (11) e0097223 Tecovirimat, also known as TPOXX or ST-246, is a drug available for the treatment of mpox. Tecovirimat targets the conserved orthopoxvirus VP37 protein (also known as F13) required for extracellular virus particle generation (1, 2). Multiple VP37 mutations associated with tecovirimat resistance have been reported within the current global mpox outbreak in immunocompromised individuals with advanced HIV infection (3 – 5). In many of these cases, resistance mutation heterogeneity was observed following tecovirimat exposure, suggesting resistance emerged under selective pressure during treatment. | To monitor circulating monkeypox virus (MPXV) within California, a genomic surveillance network was established whereby clinical and commercial laboratories provided positive specimens for whole-genome sequencing using an amplicon-based protocol and subsequent analysis (6 – 9). Through this surveillance, 11 mpox cases were identified in southern California with the same tecovirimat resistance-associated mutation (Table 1): a three-nucleotide deletion in the vaccinia virus Copenhagen F13L gene homolog (OPG057) resulting in asparagine removed from position 267 in the VP37 protein (VP37:N267del) (5) (https://www.fda.gov/emergency-preparedness-and-response/mcm-issues/fda-mpox-response#therapeutics). VP37:N267del was the only tecovirimat resistance-associated mutation detected in identified specimens and had allele frequencies greater than 89% in all instances, suggesting infections may have occurred with predominantly mutant virus. Phenotypic testing in vitro (3 – 5) confirmed tecovirimat resistance in ten identified specimens with EC50 values ranging from 1.488 to 3.977 µM, corresponding to an 85- to 230-fold change compared to wild-type isolates. |
Resistance to anti-orthopoxviral drug tecovirimat (TPOXX) during the 2022 mpox outbreak in the US (preprint)
Smith TG , Gigante CM , Wynn NT , Matheny A , Davidson W , Yang Y , Condori RE , O'Connell K , Kovar L , Williams TL , Yu YC , Petersen BW , Baird N , Lowe D , Li Y , Satheshkumar PS , Hutson CL . medRxiv 2023 18 Background: During the 2022 multinational outbreak of monkeypox virus (MPXV) clade IIb, the antiviral drug tecovirimat (TPOXX) was deployed in the US on a large scale for the first time ever. The MPXV F13L gene homolog encodes the target of tecovirimat, and single amino acid changes in the F13 protein are known to cause resistance to tecovirimat in orthopoxviruses (OPXV). Method(s): Whole genome metagenomic sequencing and amplicon-based sequencing targeting the F13L gene was used to identify nine mutations previously reported to cause resistance in other OPXV along with ten novel mutations that have been identified from the 2022 mpox outbreak. A cytopathic effect assay, previously established at CDC as part of WHO smallpox research, was adapted to MPXV for tecovirimat phenotype testing of virus isolated from mpox patients. Result(s): As of March 2023, in total, 70 isolates from 40 patients were tested, and 50 of these isolates from 26 patients were found to have a resistant phenotype. Most resistant isolates were associated with severely immunocompromised mpox patients on multiple courses of TPOXX treatment; while isolates with F13 mutations identified by routine surveillance of patients not treated with TPOXX have remained sensitive. Conclusion(s): These data indicate that tecovirimat resistance is developing in immunocompromised patients treated with TPOXX and that for isolates that we have analyzed, the frequency of resistant viruses remain relatively low (< 1%) compared to the total number of patients treated with TPOXX. These findings inform our understanding of when tecovirimat resistance is likely to occur and highlight the need for additional OPXV therapeutics. Copyright The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Multiple lineages of Monkeypox virus detected in the United States, 2021-2022 (preprint)
Gigante CM , Korber B , Seabolt MH , Wilkins K , Davidson W , Rao AK , Zhao H , Hughes CM , Minhaj F , Waltenburg MA , Theiler J , Smole S , Gallagher GR , Blythe D , Myers R , Schulte J , Stringer J , Lee P , Mendoza RM , Griffin-Thomas LA , Crain J , Murray J , Atkinson A , Gonzalez AH , Nash J , Batra D , Damon I , McQuiston J , Hutson CL , McCollum AM , Li Y . bioRxiv 2022 11 (6619) 560-565 Monkeypox is a viral zoonotic disease endemic in Central and West Africa. In May 2022, dozens of non-endemic countries reported hundreds of monkeypox cases, most with no epidemiological link to Africa. We identified two lineages of Monkeypox virus (MPXV) among nine 2021 and 2022 U.S. monkeypox cases. A 2021 case was highly similar to the 2022 MPXV outbreak variant, suggesting a common ancestor. Analysis of mutations among these two lineages revealed an extreme preference for GA-to-AA mutations indicative of APOBEC3 cytosine deaminase activity that was shared among West African MPXV since 2017 but absent from Congo Basin lineages. Poxviruses are not thought to be subject to APOBEC3 editing; however, these findings suggest APOBEC3 activity has been recurrent and dominant in recent West African MPXV evolution. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Genomic deletions and rearrangements in monkeypox virus from the 2022 outbreak, USA (preprint)
Gigante CM , Plumb M , Ruprecht A , Zhao H , Wicker V , Wilkins K , Matheny A , Khan T , Davidson W , Sheth M , Burgin A , Burroughs M , Padilla J , Lee JS , Batra D , Hetrick EE , Howard DT , Garfin J , Tate L , Hubsmith SJ , Mendoza RM , Stanek D , Gillani S , Lee M , Mangla A , Blythe D , SierraPatev S , Carpenter-Azevedo K , Huard RC , Gallagher G , Hall J , Ash S , Kovar L , Seabolt MH , Weigand MR , Damon I , Satheshkumar PS , McCollum AM , Hutson CL , Wang X , Li Y . bioRxiv 2022 17 Genomic surveillance of monkeypox virus (MPXV) during the 2022 outbreak has been mainly focused on single nucleotide polymorphism (SNP) changes. DNA viruses, including MPXV, have a lower SNP mutation rate than RNA viruses due to higher fidelity replication machinery. We identified a large genomic rearrangement in a MPXV sequence from a 2022 case in the state of Minnesota (MN), USA, from an abnormal, uneven MPXV read mapping coverage profile in whole-genome sequencing (WGS) data. We further screened WGS data of 206 U.S. MPXV samples and found seven (3.4 percent) sequenced genomes contained similar abnormal read coverage profiles that suggested putative large deletions or genomic rearrangements. Here, we present three MPXV genomes containing deletions ranging from 2.3 to 15 kb and four genomes containing more complex rearrangements. Five genomic changes were each only seen in one sample, but two sequences from linked cases shared an identical 2.3 kb deletion in the 3' terminal region. All samples were positive using VAC1 and Clade II (formerly West African)-specific MPXV diagnostic tests; however, large deletions and genomic rearrangements like the ones reported here have the potential to result in viruses in which the target of a PCR diagnostic test is deleted. The emergence of genomic rearrangements during the outbreak may have public health implications and highlight the importance of continued genomic surveillance. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Identification of tecovirimat resistance-associated mutations in human monkeypox virus - Los Angeles County
Garrigues JM , Hemarajata P , Karan A , Shah NK , Alarcón J , Marutani AN , Finn L , Smith TG , Gigante CM , Davidson W , Wynn NT , Hutson CL , Kim M , Terashita D , Balter SE , Green NM . Antimicrob Agents Chemother 2023 67 (7) e0056823 Tecovirimat (also known as TPOXX or ST-246) is a drug available for the treatment of mpox through the Centers for Disease Control and Prevention’s Expanded Access Investigational New Drug “compassionate use” protocol (https://www.cdc.gov/poxvirus/monkeypox/clinicians/Tecovirimat.html). In Los Angeles County, a fatal case of mpox with tecovirimat resistance was previously reported (1). Epidemiologic surveillance in Los Angeles County has since identified additional cases of severe mpox that did not improve after multiple rounds of tecovirimat treatment, including one involving a person who succumbed to infection (Table 1). Consistent with reports describing severe manifestations of mpox within the current global outbreak (1, 2), the identified cases involved host immunodeficiency due to advanced HIV infection. |
The CDC domestic mpox response - United States, 2022-2023
McQuiston JH , Braden CR , Bowen MD , McCollum AM , McDonald R , Carnes N , Carter RJ , Christie A , Doty JB , Ellington S , Fehrenbach SN , Gundlapalli AV , Hutson CL , Kachur RE , Maitland A , Pearson CM , Prejean J , Quilter LAS , Rao AK , Yu Y , Mermin J . MMWR Morb Mortal Wkly Rep 2023 72 (20) 547-552 Monkeypox (mpox) is a serious viral zoonosis endemic in west and central Africa. An unprecedented global outbreak was first detected in May 2022. CDC activated its emergency outbreak response on May 23, 2022, and the outbreak was declared a Public Health Emergency of International Concern on July 23, 2022, by the World Health Organization (WHO),* and a U.S. Public Health Emergency on August 4, 2022, by the U.S. Department of Health and Human Services.(†) A U.S. government response was initiated, and CDC coordinated activities with the White House, the U.S. Department of Health and Human Services, and many other federal, state, and local partners. CDC quickly adapted surveillance systems, diagnostic tests, vaccines, therapeutics, grants, and communication systems originally developed for U.S. smallpox preparedness and other infectious diseases to fit the unique needs of the outbreak. In 1 year, more than 30,000 U.S. mpox cases were reported, more than 140,000 specimens were tested, >1.2 million doses of vaccine were administered, and more than 6,900 patients were treated with tecovirimat, an antiviral medication with activity against orthopoxviruses such as Variola virus and Monkeypox virus. Non-Hispanic Black (Black) and Hispanic or Latino (Hispanic) persons represented 33% and 31% of mpox cases, respectively; 87% of 42 fatal cases occurred in Black persons. Sexual contact among gay, bisexual, and other men who have sex with men (MSM) was rapidly identified as the primary risk for infection, resulting in profound changes in our scientific understanding of mpox clinical presentation, pathogenesis, and transmission dynamics. This report provides an overview of the first year of the response to the U.S. mpox outbreak by CDC, reviews lessons learned to improve response and future readiness, and previews continued mpox response and prevention activities as local viral transmission continues in multiple U.S. jurisdictions (Figure). |
Mpox respiratory transmission: the state of the evidence.
Beeson A , Styczynski A , Hutson CL , Whitehill F , Angelo KM , Minhaj FS , Morgan C , Ciampaglio K , Reynolds MG , McCollum AM , Guagliardo SAJ . Lancet Microbe 2023 4 (4) e277-e283 The relative contribution of the respiratory route to transmission of mpox (formerly known as monkeypox) is unclear. We review the evidence for respiratory transmission of monkeypox virus (MPXV), examining key works from animal models, human outbreaks and case reports, and environmental studies. Laboratory experiments have initiated MPXV infection in animals via respiratory routes. Some animal-to-animal respiratory transmission has been shown in controlled studies, and environmental sampling studies have detected airborne MPXV. Reports from real-life outbreaks demonstrate that transmission is associated with close contact, and although it is difficult to infer the route of MPXV acquisition in individual case reports, so far respiratory transmission has not been specifically implicated. Based on the available evidence, the likelihood of human-to-human MPXV respiratory transmission appears to be low; however, studies should continue to assess this possibility. |
Evidence of mpox virus infection among persons without characteristic lesions or rash presenting for first dose of JYNNEOS vaccine-District of Columbia, August 2022
Ogale YP , Baird N , Townsend MB , Berry I , Griffin I , Lee M , Ashley P , Rhodes T , Notigan T , Wynn N , Kling C , Smith T , Priyamvada L , Carson WC , Navarra T , Dawson P , Weidle PJ , Willut C , Mangla AT , Satheshkumar PS , Hutson CL , Jackson DA , Waltenburg MA . Clin Infect Dis 2023 77 (2) 298-302 We assessed mpox virus prevalence in blood, pharyngeal, and rectal specimens among persons without characteristic rash presenting for JYNNEOS vaccine. Our data indicate that the utility of risk-based screening for mpox in persons without skin lesions or rash via pharyngeal swabs, rectal swabs, and/or blood is likely limited. |
An Mpox-related death in the United States
Alarcón J , Kim M , Terashita D , Davar K , Garrigues JM , Guccione JP , Evans MG , Hemarajata P , Wald-Dickler N , Holtom P , Garcia Tome R , Anyanwu L , Shah NK , Miller M , Smith T , Matheny A , Davidson W , Hutson CL , Lucas J , Ukpo OC , Green NM , Balter SE . N Engl J Med 2023 388 (13) 1246-1247 Since May 2022, when the multinational mpox (formerly known as monkeypox) clade IIb virus outbreak was first reported, more than 30,000 cases have been identified in the United States.1 In one study involving more than 1900 patients with mpox, more than 35% of the patients also had human immunodeficiency virus (HIV) infection.2 | | We report a death due to mpox in a patient in the United States. A 33-year-old man with HIV infection (CD4+ T-cell count, <35 per cubic millimeter) and recently treated syphilis became infected with mpox virus (MPXV) (clade IIb). He received two courses of oral tecovirimat (from Aug. 6 through Aug. 20, 2022, and from Aug. 21 through Sept. 4, 2022) and died on hospital day 27. |
Epidemiology of human mpox - worldwide, 2018-2021
McCollum AM , Shelus V , Hill A , Traore T , Onoja B , Nakazawa Y , Doty JB , Yinka-Ogunleye A , Petersen BW , Hutson CL , Lewis R . MMWR Morb Mortal Wkly Rep 2023 72 (3) 68-72 Monkeypox (mpox) is a zoonotic disease caused by Monkeypox virus (MPXV), an Orthopoxvirus; the wild mammalian reservoir species is not known. There are two genetic clades of MPXV: clade I and clade II (historically found in central and west Africa, respectively), with only Cameroon reporting both clades (1). Human cases have historically been reported from 1) mostly rural, forested areas in some central and west African countries; 2) countries reporting cases related to population migration or travel of infected persons; and 3) exposure to imported infected mammals (2). The annual number of cases in Africa has risen since 2014 and cumulatively surpassed reports from the previous 40 years for most countries. This reemergence of mpox might be due to a combination of environmental and ecological changes, animal or human movement, the cessation of routine smallpox vaccination since its eradication in 1980, improvements in disease detection and diagnosis, and genetic changes in the virus (2). This report describes the epidemiology of mpox since 1970 and during 2018-2021, using data from national surveillance programs, World Health Organization (WHO) bulletins, and case reports, and addresses current diagnostic and treatment challenges in countries with endemic disease. During 2018-2021, human cases were recognized and confirmed in six African countries, with most detected in the Democratic Republic of the Congo (DRC) and Nigeria. The reemergence and increase in cases resulted in its being listed in 2019 as a priority disease for immediate and routine reporting through the Integrated Disease Surveillance and Response strategy in the WHO African region.* In eight instances, patients with mpox were identified in four countries outside of Africa after travel from Nigeria. Since 2018, introductory and intermediate training courses on prevention and control of mpox for public health and health care providers have been available online at OpenWHO.(†)(,)(§) The global outbreak that began in May 2022(¶) has further highlighted the need for improvements in laboratory-based surveillance and access to treatments and vaccines to prevent and contain the infection, including in areas of Africa with endemic mpox. |
Multiple lineages of monkeypox virus detected in the United States, 2021-2022.
Gigante CM , Korber B , Seabolt MH , Wilkins K , Davidson W , Rao AK , Zhao H , Smith TG , Hughes CM , Minhaj F , Waltenburg MA , Theiler J , Smole S , Gallagher GR , Blythe D , Myers R , Schulte J , Stringer J , Lee P , Mendoza RM , Griffin-Thomas LA , Crain J , Murray J , Atkinson A , Gonzalez AH , Nash J , Batra D , Damon I , McQuiston J , Hutson CL , McCollum AM , Li Y . Science 2022 378 (6619) eadd4153 Monkeypox is a viral zoonotic disease endemic in Central and West Africa. In May 2022, dozens of non-endemic countries reported hundreds of monkeypox cases, most with no epidemiological link to Africa. We identified two lineages of monkeypox virus (MPXV) among two 2021 and seven 2022 U.S. monkeypox cases: the major 2022 outbreak variant, B.1, and a minor contemporaneously sampled variant called A.2. Analyses of mutations among these two variants revealed an extreme preference for GA-to-AA mutations indicative of human APOBEC3 cytosine deaminase activity among Clade IIb MPXV (previously West African, Nigeria) sampled since 2017. Such mutations were not enriched within other MPXV clades. These findings suggest that APOBEC3 editing may be a recurrent and a dominant driver of MPXV evolution within the current outbreak. |
Orthopoxvirus Testing Challenges for Persons in Populations at Low Risk or Without Known Epidemiologic Link to Monkeypox - United States, 2022.
Minhaj FS , Petras JK , Brown JA , Mangla AT , Russo K , Willut C , Lee M , Beverley J , Harold R , Milroy L , Pope B , Gould E , Beeler C , Schneider J , Mostafa HH , Godfred-Cato S , Click ES , Borah BF , Galang RR , Cash-Goldwasser S , Wong JM , McCormick DW , Yu PA , Shelus V , Carpenter A , Schatzman S , Lowe D , Townsend MB , Davidson W , Wynn NT , Satheshkumar PS , O'Connor SM , O'Laughlin K , Rao AK , McCollum AM , Negrón ME , Hutson CL , Salzer JS . MMWR Morb Mortal Wkly Rep 2022 71 (36) 1155-1158 Since May 2022, approximately 20,000 cases of monkeypox have been identified in the United States, part of a global outbreak occurring in approximately 90 countries and currently affecting primarily gay, bisexual, and other men who have sex with men (MSM) (1). Monkeypox virus (MPXV) spreads from person to person through close, prolonged contact; a small number of cases have occurred in populations who are not MSM (e.g., women and children), and testing is recommended for persons who meet the suspected case definition* (1). CDC previously developed five real-time polymerase chain reaction (PCR) assays for detection of orthopoxviruses from lesion specimens (2,3). CDC was granted 510(k) clearance for the nonvariola-orthopoxvirus (NVO)-specific PCR assay by the Food and Drug Administration. This assay was implemented within the Laboratory Response Network (LRN) in the early 2000s and became critical for early detection of MPXV and implementation of public health action in previous travel-associated cases as well as during the current outbreak (4-7). PCR assays (NVO and other Orthopoxvirus laboratory developed tests [LDT]) represent the primary tool for monkeypox diagnosis. These tests are highly sensitive, and cross-contamination from other MPXV specimens being processed, tested, or both alongside negative specimens can occasionally lead to false-positive results. This report describes three patients who had atypical rashes and no epidemiologic link to a monkeypox case or known risk factors; these persons received diagnoses of monkeypox based on late cycle threshold (Ct) values ≥34, which were false-positive test results. The initial diagnoses were followed by administration of antiviral treatment (i.e., tecovirimat) and JYNNEOS vaccine postexposure prophylaxis (PEP) to patients' close contacts. After receiving subsequent testing, none of the three patients was confirmed to have monkeypox. Knowledge gained from these and other cases resulted in changes to CDC guidance. When testing for monkeypox in specimens from patients without an epidemiologic link or risk factors or who do not meet clinical criteria (or where these are unknown), laboratory scientists should reextract and retest specimens with late Ct values (based on this report, Ct ≥34 is recommended) (8). CDC can be consulted for complex cases including those that appear atypical or questionable cases and can perform additional viral species- and clade-specific PCR testing and antiorthopoxvirus serologic testing. |
Rapid diagnostic testing for response to the monkeypox outbreak - Laboratory Response Network, United States, May 17-June 30, 2022
Aden TA , Blevins P , York SW , Rager S , Balachandran D , Hutson CL , Lowe D , Mangal CN , Wolford T , Matheny A , Davidson W , Wilkins K , Cook R , Roulo RM , White MK , Berman L , Murray J , Laurance J , Francis D , Green NM , Berumen RA3rd , Gonzalez A , Evans S , Hudziec M , Noel D , Adjei M , Hovan G , Lee P , Tate L , Gose RB , Voermans R , Crew J , Adam PR , Haydel D , Lukula S , Matluk N , Shah S , Featherston J , Ware D , Pettit D , McCutchen E , Acheampong E , Buttery E , Gorzalski A , Perry M , Fowler R , Lee RB , Nickla R , Huard R , Moore A , Jones K , Johnson R , Swaney E , Jaramillo J , Reinoso Webb C , Guin B , Yost J , Atkinson A , Griffin-Thomas L , Chenette J , Gant J , Sterkel A , Ghuman HK , Lute J , Smole SC , Arora V , Demontigny CK , Bielby M , Geeter E , Newman KAM , Glazier M , Lutkemeier W , Nelson M , Martinez R , Chaitram J , Honein MA , Villanueva JM . MMWR Morb Mortal Wkly Rep 2022 71 (28) 904-907 As part of public health preparedness for infectious disease threats, CDC collaborates with other U.S. public health officials to ensure that the Laboratory Response Network (LRN) has diagnostic tools to detect Orthopoxviruses, the genus that includes Variola virus, the causative agent of smallpox. LRN is a network of state and local public health, federal, U.S. Department of Defense (DOD), veterinary, food, and environmental testing laboratories. CDC developed, and the Food and Drug Administration (FDA) granted 510(k) clearance* for the Non-variola Orthopoxvirus Real-time PCR Primer and Probe Set (non-variola Orthopoxvirus [NVO] assay), a polymerase chain reaction (PCR) diagnostic test to detect NVO. On May 17, 2022, CDC was contacted by the Massachusetts Department of Public Health (DPH) regarding a suspected case of monkeypox, a disease caused by the Orthopoxvirus Monkeypox virus. Specimens were collected and tested by the Massachusetts DPH public health laboratory with LRN testing capability using the NVO assay. Nationwide, 68 LRN laboratories had capacity to test approximately 8,000 NVO tests per week during June. During May 17-June 30, LRN laboratories tested 2,009 specimens from suspected monkeypox cases. Among those, 730 (36.3%) specimens from 395 patients were positive for NVO. NVO-positive specimens from 159 persons were confirmed by CDC to be monkeypox; final characterization is pending for 236. Prompt identification of persons with infection allowed rapid response to the outbreak, including isolation and treatment of patients, administration of vaccines, and other public health action. To further facilitate access to testing and increase convenience for providers and patients by using existing provider-laboratory relationships, CDC and LRN are supporting five large commercial laboratories with a national footprint (Aegis Science, LabCorp, Mayo Clinic Laboratories, Quest Diagnostics, and Sonic Healthcare) to establish NVO testing capacity of 10,000 specimens per week per laboratory. On July 6, 2022, the first commercial laboratory began accepting specimens for NVO testing based on clinician orders. |
A cocktail of human monoclonal antibodies broadly neutralizes North American rabies virus variants as a promising candidate for rabies post-exposure prophylaxis.
Ejemel M , Smith TG , Greenberg L , Carson WC , Lowe D , Yang Y , Jackson FR , Morgan CN , Martin BE , Kling C , Hutson CL , Gallardo-Romero N , Ellison JA , Moore S , Buzby A , Sullivan-Bolyai J , Klempner M , Wang Y . Sci Rep 2022 12 (1) 9403 Human rabies remains a globally significant public health problem. Replacement of polyclonal anti-rabies immunoglobulin (RIG), a passive component of rabies post-exposure prophylaxis (PEP), with a monoclonal antibody (MAb), would eliminate the cost and availability constraints associated with RIG. Our team has developed and licensed a human monoclonal antibody RAB1 (Rabishield()), as the replacement for RIG where canine rabies is enzootic. However, for the highly diverse rabies viruses of North America, a cocktail containing two or more MAbs targeting different antigenic sites of the rabies glycoprotein should be included to ensure neutralization of all variants of the virus. In this study, two MAb cocktails, R172 (RAB1-RAB2) and R173 (RAB1-CR57), were identified and evaluated against a broad range of rabies variants from North America. R173 was found to be the most potent cocktail, as it neutralized all the tested North American RABV isolates and demonstrated broad coverage of isolates from both terrestrial and bat species. R173 could be a promising candidate as an alternative or replacement for RIG PEP in North America. |
Analysis of the initial lot of the CDC 2019-Novel Coronavirus (2019-nCoV) real-time RT-PCR diagnostic panel.
Lee JS , Goldstein JM , Moon JL , Herzegh O , Bagarozzi DAJr , Oberste MS , Hughes H , Bedi K , Gerard D , Cameron B , Benton C , Chida A , Ahmad A , Petway DJJr , Tang X , Sulaiman N , Teklu D , Batra D , Howard D , Sheth M , Kuhnert W , Bialek SR , Hutson CL , Pohl J , Carroll DS . PLoS One 2021 16 (12) e0260487 At the start of the COVID-19 pandemic, the Centers for Disease Control and Prevention (CDC) designed, manufactured, and distributed the CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel for SARS-CoV-2 detection. The diagnostic panel targeted three viral nucleocapsid gene loci (N1, N2, and N3 primers and probes) to maximize sensitivity and to provide redundancy for virus detection if mutations occurred. After the first distribution of the diagnostic panel, state public health laboratories reported fluorescent signal in the absence of viral template (false-positive reactivity) for the N3 component and to a lesser extent for N1. This report describes the findings of an internal investigation conducted by the CDC to identify the cause(s) of the N1 and N3 false-positive reactivity. For N1, results demonstrate that contamination with a synthetic template, that occurred while the "bulk" manufactured materials were located in a research lab for quality assessment, was the cause of false reactivity in the first lot. Base pairing between the 3' end of the N3 probe and the 3' end of the N3 reverse primer led to amplification of duplex and larger molecules resulting in false reactivity in the N3 assay component. We conclude that flaws in both assay design and handling of the "bulk" material, caused the problems with the first lot of the 2019-nCoV Real-Time RT-PCR Diagnostic Panel. In addition, within this study, we found that the age of the examined diagnostic panel reagents increases the frequency of false positive results for N3. We discuss these findings in the context of improvements to quality control, quality assurance, and assay validation practices that have since been improved at the CDC. |
Teaching a new mouse old tricks: Humanized mice as an infection model for Variola virus
Hutson CL , Kondas AV , Ritter JM , Reed Z , Ostergaard SD , Morgan CN , Gallardo-Romero N , Tansey C , Mauldin MR , Salzer JS , Hughes CM , Goldsmith CS , Carroll D , Olson VA . PLoS Pathog 2021 17 (9) e1009633 Smallpox, caused by the solely human pathogen Variola virus (VARV), was declared eradicated in 1980. While known VARV stocks are secure, smallpox remains a bioterrorist threat agent. Recent U.S. Food and Drug Administration approval of the first smallpox anti-viral (tecovirimat) therapeutic was a successful step forward in smallpox preparedness; however, orthopoxviruses can become resistant to treatment, suggesting a multi-therapeutic approach is necessary. Animal models are required for testing medical countermeasures (MCMs) and ideally MCMs are tested directly against the pathogen of interest. Since VARV only infects humans, a representative animal model for testing therapeutics directly against VARV remains a challenge. Here we show that three different humanized mice strains are highly susceptible to VARV infection, establishing the first small animal model using VARV. In comparison, the non-humanized, immunosuppressed background mouse was not susceptible to systemic VARV infection. Following an intranasal VARV challenge that mimics the natural route for human smallpox transmission, the virus spread systemically within the humanized mouse before mortality (~ 13 days post infection), similar to the time from exposure to symptom onset for ordinary human smallpox. Our identification of a permissive/representative VARV animal model can facilitate testing of MCMs in a manner consistent with their intended use. |
Pharmacokinetics and efficacy of a potential smallpox therapeutic, brincidofovir, in a lethal monkeypox virus animal model
Hutson CL , Kondas AV , Mauldin MR , Doty JB , Grossi IM , Morgan CN , Ostergaard SD , Hughes CM , Nakazawa Y , Kling C , Martin BE , Ellison JA , Carroll DD , Gallardo-Romero NF , Olson VA . mSphere 2021 6 (1) Smallpox, caused by Variola virus (VARV), was eradicated in 1980; however, VARV bioterrorist threats still exist, necessitating readily available therapeutics. Current preparedness activities recognize the importance of oral antivirals and recommend therapeutics with different mechanisms of action. Monkeypox virus (MPXV) is closely related to VARV, causing a highly similar clinical human disease, and can be used as a surrogate for smallpox antiviral testing. The prairie dog MPXV model has been characterized and used to study the efficacy of antipoxvirus therapeutics, including recently approved TPOXX (tecovirimat). Brincidofovir (BCV; CMX001) has shown antiviral activity against double-stranded DNA viruses, including poxviruses. To determine the exposure of BCV following oral administration to prairie dogs, a pharmacokinetics (PK) study was performed. Analysis of BCV plasma concentrations indicated variability, conceivably due to the outbred nature of the animals. To determine BCV efficacy in the MPXV prairie dog model, groups of animals were intranasally challenged with 9 × 10(5) plaque-forming units (PFU; 90% lethal dose [LD(90)]) of MPXV on inoculation day 0 (ID0). Animals were divided into groups based on the first day of BCV treatment relative to inoculation day (ID-1, ID0, or ID1). A trend in efficacy was noted dependent upon treatment initiation (57% on ID-1, 43% on ID0, and 29% on ID1) but was lower than demonstrated in other animal models. Analysis of the PK data indicated that BCV plasma exposure (maximum concentration [C (max)]) and the time of the last quantifiable concentration (AUC(last)) were lower than in other animal models administered the same doses, indicating that suboptimal BCV exposure may explain the lower protective effect on survival.IMPORTANCE Preparedness activities against highly transmissible viruses with high mortality rates have been highlighted during the ongoing coronavirus disease 2019 (COVID-19) pandemic. Smallpox, caused by variola virus (VARV) infection, is highly transmissible, with an estimated 30% mortality. Through an intensive vaccination campaign, smallpox was declared eradicated in 1980, and routine smallpox vaccination of individuals ceased. Today's current population has little/no immunity against VARV. If smallpox were to reemerge, the worldwide results would be devastating. Recent FDA approval of one smallpox antiviral (tecovirimat) was a successful step in biothreat preparedness; however, orthopoxviruses can become resistant to treatment, suggesting the need for multiple therapeutics. Our paper details the efficacy of the investigational smallpox drug brincidofovir in a monkeypox virus (MPXV) animal model. Since brincidofovir has not been tested in vivo against smallpox, studies with the related virus MPXV are critical in understanding whether it would be protective in the event of a smallpox outbreak. |
Lyssavirus Vaccine with a Chimeric Glycoprotein Protects across Phylogroups.
Fisher CR , Lowe DE , Smith TG , Yang Y , Hutson CL , Wirblich C , Cingolani G , Schnell MJ . Cell Rep 2020 32 (3) 107920 Rabies is nearly 100% lethal in the absence of treatment, killing an estimated 59,000 people annually. Vaccines and biologics are highly efficacious when administered properly. Sixteen rabies-related viruses (lyssaviruses) are similarly lethal, but some are divergent enough to evade protection from current vaccines and biologics, which are based only on the classical rabies virus (RABV). Here we present the development and characterization of LyssaVax, a vaccine featuring a structurally designed, functional chimeric glycoprotein (G) containing immunologically important domains from both RABV G and the highly divergent Mokola virus (MOKV) G. LyssaVax elicits high titers of antibodies specific to both RABV and MOKV Gs in mice. Immune sera also neutralize a range of wild-type lyssaviruses across the major phylogroups. LyssaVax-immunized mice are protected against challenge with recombinant RABV and MOKV. Altogether, LyssaVax demonstrates the utility of structural modeling in vaccine design and constitutes a broadened lyssavirus vaccine candidate. |
Magnitude and diversity of immune response to vaccinia virus is dependent on route of administration
Hughes LJ , Townsend MB , Gallardo-Romero N , Hutson CL , Patel N , Doty JB , Salzer JS , Damon IK , Carroll DS , Satheshkumar PS , Karem KL . Virology 2020 544 55-63 Historic observations suggest that survivors of smallpox maintained lifelong immunity and protection to subsequent infection compared to vaccinated individuals. Although protective immunity by vaccination using a related virus (vaccinia virus (VACV) strains) was the key for smallpox eradication, it does not uniformly provide long term, or lifelong protective immunity (Heiner et al., 1971). To determine differences in humoral immune responses, mice were inoculated with VACV either systemically, using intranasal inoculation (IN), or locally by an intradermal (ID) route. We hypothesized that sub-lethal IN infections may mimic systemic or naturally occurring infection and lead to an immunodominance reaction, in contrast to localized ID immunization. The results demonstrated systemic immunization through an IN route led to enhanced adaptive immunity to VACV-expressed protein targets both in magnitude and in diversity when compared to an ID route using a VACV protein microarray. In addition, cytokine responses, assessed using a Luminex(R) mouse cytokine multiplex kit, following IN infection was greater than that stemming from ID infection. Overall, the results suggest that the route of immunization (or infection) influences antibody responses. The greater magnitude and diversity of response in systemic infection provides indirect evidence for anecdotal observations made during the smallpox era that survivors maintain lifelong protection. These findings also suggest that systemic or disseminated host immune induction may result in a superior response, that may influence the magnitude of, as well as duration of protective responses. |
Antiviral ranpirnase TMR-001 inhibits rabies virus release and cell-to-cell infection in vitro
Smith TG , Jackson FR , Morgan CN , Carson WC , Martin BE , Gallardo-Romero N , Ellison JA , Greenberg L , Hodge T , Squiquera L , Sulley J , Olson VA , Hutson CL . Viruses 2020 12 (2) Currently, no rabies virus-specific antiviral drugs are available. Ranpirnase has strong antitumor and antiviral properties associated with its ribonuclease activity. TMR-001, a proprietary bulk drug substance solution of ranpirnase, was evaluated against rabies virus in three cell types: mouse neuroblastoma, BSR (baby hamster kidney cells), and bat primary fibroblast cells. When TMR-001 was added to cell monolayers 24 h preinfection, rabies virus release was inhibited for all cell types at three time points postinfection. TMR-001 treatment simultaneous with infection and 24 h postinfection effectively inhibited rabies virus release in the supernatant and cell-to-cell spread with 50% inhibitory concentrations of 0.2-2 nM and 20-600 nM, respectively. TMR-001 was administered at 0.1 mg/kg via intraperitoneal, intramuscular, or intravenous routes to Syrian hamsters beginning 24 h before a lethal rabies virus challenge and continuing once per day for up to 10 days. TMR-001 at this dose, formulation, and route of delivery did not prevent rabies virus transit from the periphery to the central nervous system in this model (n = 32). Further aspects of local controlled delivery of other active formulations or dose concentrations of TMR-001 or ribonuclease analogues should be investigated for this class of drugs as a rabies antiviral therapeutic. |
Use of live Variola virus to determine whether CAST/EiJ mice are a suitable surrogate animal model for human smallpox
Gallardo-Romero NF , Hutson CL , Carroll D , Kondas AV , Salzer JS , Dietz-Ostergaard S , Smith S , Hudson P , Olson V , Damon I . Virus Res 2019 275 197772 Numerous animal models of systemic orthopoxvirus disease have been developed to evaluate therapeutics against variola virus (VARV), the causative agent of smallpox. These animal models do not resemble the disease presentation in human smallpox and most used surrogate Orthopoxviruses. A rodent model using VARV has a multitude of advantages, and previous investigations identified the CAST/EiJ mouse as highly susceptible to monkeypox virus infection, making it of interest to determine if these rodents are also susceptible to VARV infection. In this study, we inoculated CAST/EiJ mice with a range of VARV doses (10(2)-10(6) plaque forming units). Some animals had detectable viable VARV from the oropharynx between days 3 and 12 post inoculation. Despite evidence of disease, the CAST/EiJ mouse does not provide a model for clinical smallpox due to mild signs of morbidity and limited skin lesions. However, in contrast to previous rodent models using VARV challenge (i.e. prairie dogs and SCID mice), a robust immune response was observed in the CAST/EiJ mice (measured by Immunoglobulin G enzyme-linked immunosorbent assay). This is an advantage of this model for the study of VARV and presents a unique potential for the study of the immunomodulatory pathways following VARV infection. |
Characterization of Monkeypox virus dissemination in the black-tailed prairie dog (Cynomys ludovicianus) through in vivo bioluminescent imaging
Weiner ZP , Salzer JS , LeMasters E , Ellison JA , Kondas AV , Morgan CN , Doty JB , Martin BE , Satheshkumar PS , Olson VA , Hutson CL . PLoS One 2019 14 (9) e0222612 Monkeypox virus (MPXV) is a member of the genus Orthopoxvirus, endemic in Central and West Africa. This viral zoonosis was introduced into the United States in 2003 via African rodents imported for the pet trade and caused 37 human cases, all linked to exposure to MPXV-infected black-tailed prairie dogs (Cynomys ludovicianus). Prairie dogs have since become a useful model of MPXV disease, utilized for testing of potential medical countermeasures. In this study, we used recombinant MPXV containing the firefly luciferase gene (luc) and in vivo imaging technology to characterize MPXV pathogenesis in the black-tailed prairie dog in real time. West African (WA) MPXV could be visualized using in vivo imaging in the nose, lymph nodes, intestines, heart, lung, kidneys, and liver as early as day 6 post infection (p.i.). By day 9 p.i., lesions became visible on the skin and in some cases in the spleen. After day 9 p.i., luminescent signal representing MPXV replication either increased, indicating a progression to what would be a fatal infection, or decreased as infection was resolved. Use of recombinant luc+ MPXV allowed for a greater understanding of how MPXV disseminates throughout the body in prairie dogs during the course of infection. This technology will be used to reduce the number of animals required in future pathogenesis studies as well as aid in determining the effectiveness of potential medical countermeasures. |
Analgesia during monkeypox virus experimental challenge studies in prairie dogs (Cynomys ludovicianus)
Hutson CL , Gallardo-Romero N , Carroll DS , Salzer JS , Ayers JD , Doty JB , Hughes CM , Nakazawa Y , Hudson P , Patel N , Keckler MS , Olson VA , Nagy T . J Am Assoc Lab Anim Sci 2019 58 (4) 485-500 Because human patients with monkeypox virus (MPXV) infection report painful symptoms, it is reasonable to assume that animals infected with MPXV experience some degree of pain. Understanding whether and how analgesics affect MPXV disease progression is crucial when planning in vivo challenge experiments. In the current study, we challenged prairie dogs with a low dose (4 x10(3) pfu) of MPXV and treated with meloxicam (NSAID) or buprenorphine (opioid); control animals did not receive analgesia or received analgesia without MPXV challenge. Subsets of animals from each group were serially euthanized during the course of the study. Disease progression and viral kinetics were similar between groups, but MXPVinfected, meloxicam-treated animals showed increasing trends of morbidity and mortality compared with other groups. Differences between no-analgesia MPXV-infected control animals and MPXV-infected animals treated with buprenorphine were minimal. The findings in the current study allow more informed decisions concerning the use of analgesics during experimental MPXV challenge studies, thereby improving animal welfare. In light of these findings, we have modified our pain scale for this animal model to include the use of buprenorphine for pain relief when warranted after MPXV challenge. |
Revisiting rabies virus neutralizing antibodies through infecting BALB/c mice with live rabies virus
Qin Y , Smith TG , Jackson F , Gallardo-Romero NF , Morgan CN , Olson V , Hutson CL , Wu X . Virus Res 2018 248 39-43 This study investigates the production of rabies virus (RABV) neutralizing antibody after virus infection through a mouse model. The BALB/c mice from different age groups (three, five, seven week old) were intramuscularly inoculated with live rabies virus (TX coyote 323R). Without pre-exposure or post-exposure prophylaxis (PEP), we found there is a decreased fatality with increased age of animals, the mortalities are 60%, 50%, and 30%, respectively. Interestingly, through assay of rapid fluorescent focus inhibition test (RFFIT), direct fluorescent antibody (DFA) and quantitative Polymerase Chain Reaction (qPCR), the results showed that all the animals that succumbed to rabies challenge, except one, developed circulating neutralizing antibodies, and all the healthy animals, except two, did not generate virus neutralizing antibodies (VNA). Our animal study suggests that the induction of VNA was an indicator of infection progression in the central nervous system (CNS) and speculate that RABV neutralizing antibodies did not cross the blood-brain barrier of the CNS for those diseased animals. We hypothesize that early release of viral antigens from damaged nerve tissue might potentially be a benefit for survivors, and we also discuss several other aspects of the interaction of RABV and its neutralizing antibodies. |
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