Last data update: Apr 29, 2024. (Total: 46658 publications since 2009)
Records 1-30 (of 64 Records) |
Query Trace: Nakazawa Y[original query] |
---|
Nowcasting and forecasting the 2022 U.S. Mpox outbreak: Support for public health decision making and lessons learned
Charniga K , Madewell ZJ , Masters NB , Asher J , Nakazawa Y , Spicknall IH . Epidemics 2024 47 100755 In June of 2022, the U.S. Centers for Disease Control and Prevention (CDC) Mpox Response wanted timely answers to important epidemiological questions which can now be answered more effectively through infectious disease modeling. Infectious disease models have shown to be valuable tools for decision making during outbreaks; however, model complexity often makes communicating the results and limitations of models to decision makers difficult. We performed nowcasting and forecasting for the 2022 mpox outbreak in the United States using the R package EpiNow2. We generated nowcasts/forecasts at the national level, by Census region, and for jurisdictions reporting the greatest number of mpox cases. Modeling results were shared for situational awareness within the CDC Mpox Response and publicly on the CDC website. We retrospectively evaluated forecast predictions at four key phases (early, exponential growth, peak, and decline) during the outbreak using three metrics, the weighted interval score, mean absolute error, and prediction interval coverage. We compared the performance of EpiNow2 with a naïve Bayesian generalized linear model (GLM). The EpiNow2 model had less probabilistic error than the GLM during every outbreak phase except for the early phase. We share our experiences with an existing tool for nowcasting/forecasting and highlight areas of improvement for the development of future tools. We also reflect on lessons learned regarding data quality issues and adapting modeling results for different audiences. |
Updating reproduction number estimates for Mpox in the Democratic Republic of Congo using surveillance data
Charniga K , McCollum AM , Hughes CM , Monroe B , Kabamba J , Lushima RS , Likafi T , Nguete B , Pukuta E , Muyamuna E , Tamfum JM , Karhemere S , Kaba D , Nakazawa Y . Am J Trop Med Hyg 2024 Incidence of human monkeypox (mpox) has been increasing in West and Central Africa, including in the Democratic Republic of Congo (DRC), where monkeypox virus (MPXV) is endemic. Most estimates of the pathogen's transmissibility in the DRC are based on data from the 1980s. Amid the global 2022 mpox outbreak, new estimates are needed to characterize the virus' epidemic potential and inform outbreak control strategies. We used the R package vimes to identify clusters of laboratory-confirmed mpox cases in Tshuapa Province, DRC. Cases with both temporal and spatial data were assigned to clusters based on the disease's serial interval and spatial kernel. We used the size of the clusters to infer the effective reproduction number, Rt, and the rate of zoonotic spillover of MPXV into the human population. Out of 1,463 confirmed mpox cases reported in Tshuapa Province between 2013 and 2017, 878 had both date of symptom onset and a location with geographic coordinates. Results include an estimated Rt of 0.82 (95% CI: 0.79-0.85) and a rate of 132 (95% CI: 122-143) spillovers per year assuming a reporting rate of 25%. This estimate of Rt is larger than most previous estimates. One potential explanation for this result is that Rt could have increased in the DRC over time owing to declining population-level immunity conferred by smallpox vaccination, which was discontinued around 1982. Rt could be overestimated if our assumption of one spillover event per cluster does not hold. Our results are consistent with increased transmissibility of MPXV in Tshuapa Province. |
An evaluation of the ecological niche of Orf virus (Poxviridae): Challenges of distinguishing broad niches from no niches
Nair RR , Nakazawa Y , Peterson AT . PLoS One 2024 19 (1) e0293312 Contagious ecthyma is a skin disease, caused by Orf virus, creating great economic threats to livestock farming worldwide. Zoonotic potential of this disease has gained recent attention owing to the re-emergence of disease in several parts of the world. Increased public health concern emphasizes the need for a predictive understanding of the geographic distributional potential of Orf virus. Here, we mapped the current distribution using occurrence records, and estimated the ecological niche in both geographical and environmental spaces. Twenty modeling experiments, resulting from two- and three-partition models, were performed to choose the candidate models that best represent the geographic distributional potential of Orf virus. For all of our models, it was possible to reject the null hypothesis of predictive performance no better than random expectations. However, statistical significance must be accompanied by sufficiently good predictive performance if a model is to be useful. In our case, omission of known distribution of the virus was noticed in all Maxent models, indicating inferior quality of our models. This conclusion was further confirmed by the independent final evaluation, using occurrence records sourced from the Centre for Agriculture and Bioscience International. Minimum volume ellipsoid (MVE) models indicated the broad range of environmental conditions under which Orf virus infections are found. The excluded climatic conditions from MVEs could not be considered as unsuitable owing to the broad distribution of Orf virus. These results suggest two possibilities: that the niche models fail to identify niche limits that constrain the virus, or that the virus has no detectable niche, as it can be found throughout the geographic distributions of its hosts. This potential limitation of component-based pathogen-only ENMs is discussed in detail. |
Modelling the impact of vaccination and sexual behaviour adaptations on mpox cases in the USA during the 2022 outbreak
Clay PA , Asher JM , Carnes N , Copen CE , Delaney KP , Payne DC , Pollock ED , Mermin J , Nakazawa Y , Still W , Mangla AT , Spicknall IH . Sex Transm Infect 2023 BACKGROUND: The 2022 mpox outbreak has infected over 30 000 people in the USA, with cases declining since mid-August. Infections were commonly associated with sexual contact between men. Interventions to mitigate the outbreak included vaccination and a reduction in sexual partnerships. Understanding the contributions of these interventions to decreasing cases can inform future public health efforts. METHODS: We fit a dynamic network transmission model to mpox cases reported by Washington DC through 10 January 2023. This model incorporated both vaccine administration data and reported reductions in sexual partner acquisition by gay, bisexual or other men who have sex with men (MSM). The model output consisted of daily cases over time with or without vaccination and/or behavioural adaptation. RESULTS: We found that initial declines in cases were likely caused by behavioural adaptations. One year into the outbreak, vaccination and behavioural adaptation together prevented an estimated 84% (IQR 67% to 91%) of cases. Vaccination alone averted 79% (IQR 64% to 88%) of cases and behavioural adaptation alone averted 25% (IQR 10% to 42%) of cases. We further found that in the absence of vaccination, behavioural adaptation would have reduced the number of cases, but would have prolonged the outbreak. CONCLUSIONS: We found that initial declines in cases were likely caused by behavioural adaptation, but vaccination averted more cases overall and was key to hastening outbreak conclusion. Overall, this indicates that outreach to encourage individuals to protect themselves from infection was vital in the early stages of the mpox outbreak, but that combination with a robust vaccination programme hastened outbreak conclusion. |
Updating reproduction number estimates for mpox in the Democratic Republic of Congo using surveillance data (preprint)
Charniga K , McCollum AM , Hughes CM , Monroe B , Kabamba J , Lushima RS , Likafi T , Nguete B , Pukuta E , Muyamuna E , Tamfum JJM , Karhemere S , Kaba D , Nakazawa Y . medRxiv 2023 17 Incidence of human mpox has been increasing in West and Central Africa, including in the Democratic Republic of Congo (DRC), where monkeypox virus (MPXV) is endemic. Most estimates of the pathogen's transmissibility in DRC are based on data from the 1980s. Amid the global 2022 mpox outbreak, new estimates are needed to characterize the virus' epidemic potential and inform outbreak control strategies. We used the R package vimes to identify clusters of laboratory-confirmed mpox cases in Tshuapa Province, DRC. Cases with both temporal and spatial data were assigned to clusters based on the disease's serial interval and spatial kernel. We used the size of the clusters to infer the effective reproduction number, R<inf>t</inf>, and the rate of zoonotic spillover of MPXV into the human population. Out of 1,463 confirmed mpox cases reported in Tshuapa Province between 2013 and 2017, 878 had both date of symptom onset and a location with geographic coordinates. Results include an estimated R<inf>t</inf> of 0.82 (95% CI: 0.79 - 0.85) and a rate of 132 (95% CI: 122 - 143) spillovers per year assuming a reporting rate of 0.25. This estimate of R<inf>t</inf> is larger compared to most previous estimates. One potential explanation for this result is that R<inf>t</inf> could have increased in DRC over time due to declining population-level immunity conferred by smallpox vaccination, which was discontinued around 1982. R<inf>t</inf> could be overestimated if our assumption of one spillover event per cluster does not hold. Our results are consistent with increased transmissibility of MPXV in Tshuapa Province. 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. |
Modelling the impact of vaccination and sexual behavior change on reported cases of mpox in Washington D.C (preprint)
Clay PA , Asher JM , Carnes N , Copen CE , Delaney KP , Payne DC , Pollock ED , Mermin J , Nakazawa Y , Still W , Mangla AT , Spicknall IH . medRxiv 2023 14 Background: The 2022 mpox outbreak infected over 30,000 people in the United States. Infections were commonly associated with sexual contact between men. Interventions included vaccination and reductions in sexual partnerships. We estimated the averted infections attributable to each intervention using mathematical modeling. Method(s): We fit a dynamic network transmission model to mpox cases reported by the District of Columbia through January 2023. We incorporated vaccine administration data and reported reductions in sexual partnerships among gay, bisexual, or other men who have sex with men (MSM). Model output consisted of predicted cases over time with or without vaccination and/or behavior change. Result(s): We estimated initial case reductions were due to behavior change. Vaccination alone averted 64% [IQR:57%-72%] and behavior change alone averted 21% [IQR:11%-29%] of cases. Vaccination and behavior change together averted 80% [IQR:74%-85%] of cases. In the absence of vaccination, behavior change reduced cumulative cases but also prolonged the outbreak. Conclusion(s): Initial case declines were likely caused by behavior change, but vaccination averted more cases overall. Overall, this indicates that encouraging individuals to protect themselves was vital in the early outbreak, but that combination with a robust vaccination program was ultimately required for control. 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. |
Nowcasting and Forecasting the 2022 U.S. Mpox Outbreak: Support for Public Health Decision Making and Lessons Learned (preprint)
Charniga K , Madewell ZJ , Masters NB , Asher J , Nakazawa Y , Spicknall IH . medRxiv 2023 17 Mpox is a zoonotic disease endemic in Central and West Africa. In May 2022, an outbreak of mpox characterized by human-to-human transmission was detected in multiple non-endemic countries. We performed nowcasting and forecasting for the 2022 mpox outbreak in the United States using the R package EpiNow2. We generated nowcasts/forecasts at the national level, by Census region, and for jurisdictions reporting the greatest number of mpox cases. Modeling results were shared for situational awareness within the Centers for Disease Control and Prevention (CDC) Mpox Response and publicly on the CDC website. We retrospectively evaluated forecast predictions at four key phases during the outbreak using three metrics, the weighted interval score, mean absolute error, and prediction interval coverage. We compared the performance of EpiNow2 with a naive Bayesian generalized linear model (GLM). The EpiNow2 model had less probabilistic error than the GLM during every outbreak phase except for the early phase. We share our experiences with an existing tool for nowcasting/forecasting and highlight areas of improvement for the development of future tools. We also reflect on lessons learned regarding data quality issues and adapting modeling results for different audiences. 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. |
Serial interval and incubation period estimates of monkeypox virus infection in 12 U.S. jurisdictions, May - August 2022 (preprint)
Madewell ZJ , Charniga K , Masters NB , Asher J , Fahrenwald L , Still W , Chen J , Kipperman N , Bui D , Shea M , Saathoff-Huber L , Johnson S , Harbi K , Berns AL , Perez T , Gateley E , Spicknall IH , Nakazawa Y , Gift TL . medRxiv 2022 30 Using data collected by 12 U.S. health departments, we report mean estimated serial interval for monkeypox virus infection of 8.5 (95% CrI: 7.3 - 9.9) days for symptom onset from 57 case pairs and mean estimated incubation period of 5.6 (4.3 - 7.8) days from 35 case pairs for symptom onset. 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. |
A Novel Restraint Device to Improve Safety and Efficacy of Blood Collection During Non-Terminal Sampling of Bats (preprint)
Morgan CN , Mauldin MR , Jones J , Collier B , Nakazawa Y . bioRxiv 2022 25 There are a variety of blood collection techniques described in the literature for unanesthetized bats, which typically require multiple sharps (e.g., needles, lancets, etc.), competent animal handling for prolonged periods, and usually involve two individuals. With the challenges inherent to non-terminal sampling of blood from bats, as well as the growing need for the use of this technique across multiple disciplines and industries, an improved blood collection method is needed. We report the creation of a bat restraint device specifically designed for a single individual to safely collect blood from anesthetized or non-anesthetized bats. The utility of this restraint device is multifaceted, serving as a safety measure for both animal and handler, as well as increasing the efficiency of blood collection. The restraint device was tested during two laboratory bat studies, Afterwards, the users of the restraint device were provided with a 10-question survey questionnaire to record their opinions on its usage. In total 80% of responses were considered positive, 15% considered neutral, and 5% considered negative. Survey questions that all participants responded to positively when in comparison to the traditional method of blood collection from bats include "easier to perform", "safer to bats", and "safer to the individual". While using the restraint devices during the laboratory studies, no needle sticks, bites, or scratches to laboratorians occurred, and no observable health issues or complication due to blood collection in the bats bled using the restraint devices. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license. |
Estimating the incubation period of monkeypox virus during the 2022 multi-national outbreak (preprint)
Charniga K , Masters NB , Slayton RB , Gosdin L , Minhaj FS , Philpott D , Smith D , Gearhart S , Alvarado-Ramy F , Brown C , Waltenburg MA , Hughes CM , Nakazawa Y . medRxiv 2022 23 Monkeypox is a zoonotic disease endemic in Central and West Africa. In May 2022, an outbreak of monkeypox characterized by human-to-human transmission was detected in multiple non-endemic countries. We estimated the incubation period for monkeypox using information from 22 probable (N = 1) and confirmed (N = 21) monkeypox cases in patients reported in the United States through June 6, 2022. We pooled U.S. patient data with the data from 18 confirmed cases in patients reported from the Netherlands through May 31, 2022. The mean incubation period from exposure to first symptom onset was 7.6 days (95% credible interval: 6.2 - 9.7), and the 95th percentile was 17.1 days (95% CrI: 12.7-24.3). These findings align with current CDC recommendations for monitoring close contacts of people with monkeypox for 21 days after their last exposure. 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. |
Risk of rabies and implications for postexposure prophylaxis administration in the US
Charniga K , Nakazawa Y , Brown J , Jeon S , Wallace RM . JAMA Netw Open 2023 6 (6) e2317121 IMPORTANCE: In the US, rabies postexposure prophylaxis (PEP) is often administered without a comprehensive and regionally appropriate rabies risk assessment. For low-risk exposures, this can result in patients incurring out-of-pocket expenses or experiencing adverse effects of PEP unnecessarily. OBJECTIVE: To use a model to estimate (1) the probability that an animal would test positive for rabies virus (RABV) given that a person was exposed, and (2) the probability that a person would die from rabies given that they were exposed to a suspect rabid animal and did not receive PEP, and to propose a risk threshold for recommending PEP according to model estimates and a survey. DESIGN, SETTING, AND PARTICIPANTS: In this decision analytical modeling study, positivity rates were calculated using more than 900 000 animal samples tested for RABV between 2011 and 2020. Other parameters were estimated from a subset of the surveillance data and the literature. Probabilities were estimated using Bayes' rule. A survey was administered among a convenience sample of state public health officials in all US states (excluding Hawaii) plus Washington, DC and Puerto Rico to determine a risk threshold for PEP recommendation. Respondents were asked whether they would recommend PEP given 24 standardized exposure scenarios while accounting for local rabies epidemiology. MAIN OUTCOMES AND MEASURES: A quantitative and regionally appropriate approach for helping health care practitioners and public health professionals determine whether to recommend and/or administer rabies PEP. RESULTS: A total of 1728 unique observations were obtained from the model for the probability that an animal would test positive for RABV given that a person was exposed, and 41 472 for ) the probability that a person would die from rabies given that they were exposed to a suspect rabid animal and did not receive PEP. The median probability that an animal would test positive for RABV given that a person was exposed ranged from 3 × 10-7 to 0.97, while the probability that a person would die from rabies given that they were exposed to a suspect rabid animal and did not receive PEP ranged from 1 × 10-10 to 0.55. Fifty public health officials out of a target sample size of 102 responded to the survey. Using logistic regression, a risk threshold was estimated for PEP recommendation of 0.0004; PEP may not be recommended for exposures with probabilities below this threshold. CONCLUSIONS AND RELEVANCE: In this modeling study of rabies in the US, the risk of death|exposure was quantified and a risk threshold was estimated. These results could be used to inform the decision-making process as to the appropriateness of recommending rabies PEP. |
Serial interval and incubation period estimates of monkeypox virus infection in 12 jurisdictions, United States, May-August 2022
Madewell ZJ , Charniga K , Masters NB , Asher J , Fahrenwald L , Still W , Chen J , Kipperman N , Bui D , Shea M , Saunders K , Saathoff-Huber L , Johnson S , Harbi K , Berns AL , Perez T , Gateley E , Spicknall IH , Nakazawa Y , Gift TL . Emerg Infect Dis 2023 29 (4) 818-821 Using data from 12 US health departments, we estimated mean serial interval for monkeypox virus infection to be 8.5 (95% credible interval 7.3-9.9) days for symptom onset, based on 57 case pairs. Mean estimated incubation period was 5.6 (95% credible interval 4.3-7.8) days for symptom onset, based on 35 case pairs. |
Orthopoxvirus circulation in an endemic area in Brazil: Investigation of infections in small mammals during an absence of outbreaks
Domingos IJS , Rocha KLS , Graciano JM , Almeida LR , Doty JB , Paglia AP , Oliveira DB , Nakazawa YJ , Trindade GS . Viruses 2023 15 (4) Vaccinia virus (VACV) is the causative agent of an emerging viral zoonosis called bovine vaccinia (BV). Several studies have documented characteristics of VACV infections in Brazil; however, the manner in which this virus is maintained in wildlife remains unknown. This work investigated the presence of viral DNA and anti-orthopoxvirus (OPXV) antibodies in samples collected from small mammals in a VACV-endemic area in Minas Gerais, Brazil, in the absence of current outbreaks. Samples did not show amplification of OPXV DNA in molecular tests. However, 5/142 serum samples demonstrated the presence of anti-OPXV neutralizing antibodies in serological tests. These data reinforce the involvement of small mammals in the natural cycle of VACV, highlighting the need for further ecological studies to better understand how this virus is maintained in nature and to develop measures to prevent BV outbreaks. |
Revealing the complexity of vampire bat rabies "spillover transmission"
Escobar LE , Velasco-Villa A , Satheshkumar PS , Nakazawa Y , Van de Vuurst P . Infect Dis Poverty 2023 12 (1) 10 BACKGROUND: The term virus 'spillover' embodies a highly complex phenomenon and is often used to refer to viral transmission from a primary reservoir host to a new, naïve yet susceptible and permissive host species. Spillover transmission can result in a virus becoming pathogenic, causing disease and death to the new host if successful infection and transmission takes place. MAIN TEXT: The scientific literature across diverse disciplines has used the terms virus spillover, spillover transmission, cross-species transmission, and host shift almost indistinctly to imply the complex process of establishment of a virus from an original host (source/donor) to a naïve host (recipient), which have close or distant taxonomic or evolutionary ties. Spillover transmission may result in unsuccessful onward transmission, if the virus dies off before propagation. Alternatively, successful viral establishment in the new host can occur if subsequent secondary transmission among individuals of the same novel species and among other sympatric susceptible species occurred. As such, virus spillover transmission is a common yet highly complex phenomenon that encompasses multiple subtle stages that can be deconstructed to be studied separately to better understand the drivers of disease emergence. Rabies virus (RABV) is a well-documented viral pathogen which still inflicts heavy impact on humans, companion animals, wildlife, and livestock throughout Latin America due substantial spatial temporal and ecological-natural and expansional-overlap with several virus reservoir hosts. Thereby, the rabies disease system represents a robust avenue through which the drivers and uncertainties surrounding spillover transmission can be unravel at its different subtle stages to better understand how they may be affected by coarse, medium, and fine scale variables. CONCLUSIONS: The continued study of viral spillover transmission necessitates the elucidation of its complexities to better assess the cross-scale impacts of ecological forces linked to the propensity of spillover success. Improving capacities to reconstruct and predict spillover transmission would prevent public health impacts on those most at risk populations across the globe. |
Orthopoxvirus infections in rodents, Nigeria, 2018-2019
Meseko C , Adedeji A , Shittu I , Obishakin E , Nanven M , Suleiman L , Okomah D , Tyakaray V , Kolade D , Yinka-Ogunleye A , Muhammad S , Morgan CN , Matheny A , Nakazawa Y , McCollum A , Doty JB . Emerg Infect Dis 2023 29 (2) 433-434 To investigate animal reservoirs of monkeypox virus in Nigeria, we sampled 240 rodents during 2018-2019. Molecular (real-time PCR) and serologic (IgM) evidence indicated orthopoxvirus infections, but presence of monkeypox virus was not confirmed. These results can be used to develop public health interventions to reduce human infection with orthopoxviruses. |
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. |
Reduced risk for Mpox after receipt of 1 or 2 doses of JYNNEOS vaccine compared with risk among unvaccinated persons - 43 U.S. Jurisdictions, July 31-October 1, 2022
Payne AB , Ray LC , Cole MM , Canning M , Houck K , Shah HJ , Farrar JL , Lewis NM , Fothergill A , White EB , Feldstein LR , Roper LE , Lee F , Kriss JL , Sims E , Spicknall IH , Nakazawa Y , Gundlapalli AV , Shimabukuro T , Cohen AL , Honein MA , Mermin J , Payne DC . MMWR Morb Mortal Wkly Rep 2022 71 (49) 1560-1564 As of October 28, 2022, a total of 28,244* monkeypox (mpox) cases have been reported in the United States during an outbreak that has disproportionately affected gay, bisexual, and other men who have sex with men (MSM) (1). JYNNEOS vaccine (Modified Vaccinia Ankara vaccine, Bavarian Nordic), administered subcutaneously as a 2-dose (0.5 mL per dose) series (with doses administered 4 weeks apart), was approved by the Food and Drug Administration (FDA) in 2019 to prevent smallpox and mpox disease (2); an FDA Emergency Use Authorization issued on August 9, 2022, authorized intradermal administration of 0.1 mL per dose, increasing the number of persons who could be vaccinated with the available vaccine supply(†) (3). A previous comparison of mpox incidence during July 31-September 3, 2022, among unvaccinated, but vaccine-eligible men aged 18-49 years and those who had received ≥1 JYNNEOS vaccine dose in 32 U.S. jurisdictions, found that incidence among unvaccinated persons was 14 times that among vaccinated persons (95% CI = 5.0-41.0) (4). During September 4-October 1, 2022, a total of 205,504 persons received JYNNEOS vaccine dose 2 in the United States.(§) To further examine mpox incidence among persons who were unvaccinated and those who had received either 1 or 2 JYNNEOS doses, investigators analyzed data on 9,544 reported mpox cases among men(¶) aged 18-49 years during July 31-October 1, 2022, from 43 U.S. jurisdictions,** by vaccination status. During this study period, mpox incidence (cases per 100,000 population at risk) among unvaccinated persons was 7.4 (95% CI = 6.0-9.1) times that among persons who received only 1 dose of JYNNEOS vaccine ≥14 days earlier and 9.6 (95% CI = 6.9-13.2) times that among persons who received dose 2 ≥14 days earlier. The observed distribution of subcutaneous and intradermal routes of administration of dose 1 among vaccinated persons with mpox was not different from the expected distribution. This report provides additional data suggesting JYNNEOS vaccine provides protection against mpox, irrespective of whether the vaccine is administered intradermally or subcutaneously. The degree and durability of such protection remains unclear. Persons eligible for mpox vaccination should receive the complete 2-dose series to optimize strength of protection(††) (5). |
Incidence of monkeypox among unvaccinated persons compared with persons receiving 1 JYNNEOS vaccine vose - 32 U.S. jurisdictions, July 31-September 3, 2022
Payne AB , Ray LC , Kugeler KJ , Fothergill A , White EB , Canning M , Farrar JL , Feldstein LR , Gundlapalli AV , Houck K , Kriss JL , Lewis NM , Sims E , Smith DK , Spicknall IH , Nakazawa Y , Damon IK , Cohn AC , Payne DC . MMWR Morb Mortal Wkly Rep 2022 71 (40) 1278-1282 Human monkeypox is caused by Monkeypox virus (MPXV), an Orthopoxvirus, previously rare in the United States (1). The first U.S. case of monkeypox during the current outbreak was identified on May 17, 2022 (2). As of September 28, 2022, a total of 25,341 monkeypox cases have been reported in the United States.* The outbreak has disproportionately affected gay, bisexual, and other men who have sex with men (MSM) (3). JYNNEOS vaccine (Modified Vaccinia Ankara vaccine, Bavarian Nordic), administered subcutaneously as a 2-dose (0.5 mL per dose) series with doses administered 4 weeks apart, was approved by the Food and Drug Administration (FDA) in 2019 to prevent smallpox and monkeypox infection (4). U.S. distribution of JYNNEOS vaccine as postexposure prophylaxis (PEP) for persons with known exposures to MPXV began in May 2022. A U.S. national vaccination strategy(†) for expanded PEP, announced on June 28, 2022, recommended subcutaneous vaccination of persons with known or presumed exposure to MPXV, broadening vaccination eligibility. FDA emergency use authorization (EUA) of intradermal administration of 0.1 mL of JYNNEOS on August 9, 2022, increased vaccine supply (5). As of September 28, 2022, most vaccine has been administered as PEP or expanded PEP. Because of the limited amount of time that has elapsed since administration of initial vaccine doses, as of September 28, 2022, relatively few persons in the current outbreak have completed the recommended 2-dose series.(§) To examine the incidence of monkeypox among persons who were unvaccinated and those who had received ≥1 JYNNEOS vaccine dose, 5,402 reported monkeypox cases occurring among males(¶) aged 18-49 years during July 31-September 3, 2022, were analyzed by vaccination status across 32 U.S. jurisdictions.** Average monkeypox incidence (cases per 100,000) among unvaccinated persons was 14.3 (95% CI = 5.0-41.0) times that among persons who received 1 dose of JYNNEOS vaccine ≥14 days earlier. Monitoring monkeypox incidence by vaccination status in timely surveillance data might provide early indications of vaccine-related protection that can be confirmed through other well-controlled vaccine effectiveness studies. This early finding suggests that a single dose of JYNNEOS vaccine provides some protection against monkeypox infection. The degree and durability of such protection is unknown, and it is recommended that people who are eligible for monkeypox vaccination receive the complete 2-dose series. |
Modeling the impact of sexual networks in the transmission of monkeypox virus among gay, bisexual, and other men who have sex with men - United States, 2022
Spicknall IH , Pollock ED , Clay PA , Oster AM , Charniga K , Masters N , Nakazawa YJ , Rainisch G , Gundlapalli AV , Gift TL . MMWR Morb Mortal Wkly Rep 2022 71 (35) 1131-1135 What is already known about this topic? The 2022 monkeypox outbreak is associated with sexual and intimate contact. Survey data suggest that gay, bisexual, and other men who have sex with men (MSM), who have been disproportionately affected, are reducing one-time partnerships. What is added by this report? Modeling of sexual infection transmission between men indicates that one-time partnerships, which account for 3% of daily sexual partnerships and 16% of daily sex acts, account for approximately 50% of daily Monkeypox virus (MPXV) transmission. A 40% reduction in one-time partnerships might delay the spread of monkeypox and reduce the percentage of persons infected by 20% to 31%. What are the implications for public health practice? Reductions in one-time partnerships, already being reported by MSM, might significantly reduce MPXV transmission. © 2022 Department of Health and Human Services. All rights reserved. |
Activity patterns and burrowing ecology of the giant pouched rat (Cricetomys emini) in Tshuapa Province, D. R. Congo
Kalemba LN , Morgan CN , Nakazawa YJ , Mauldin MR , Malekani JM , Doty JB . Mammalia 2022 86 (6) 562-569 Rodents of the genus Cricetomys have been reported to be nocturnal with a bimodal activity pattern and to frequently change burrows. However, no studies to date have examined these ecological aspects with the use of radio-telemetry. Five C. emini were captured and radio-collared to study their activity patterns and burrowing ecology from 9 March to 15 April 2016. Nocturnal activity ranged between the hours of 18:00 and 05:00 with a probable reduction of activities between 20:00-23:00 and around 04:00 with diurnal activity between 06:00 and 17:00 h with a reduction of activity between 11:00 and 14:00. While the present study does confirm nocturnal activity and a bimodal pattern, this study also suggests greater diurnal activity as compared to previous studies. Additionally, data presented here also suggest that C. emini may not change burrows as frequently as previously reported. 2022 Walter de Gruyter GmbH, Berlin/Boston 2022. |
A Cross Sectional Sampling Reveals Novel Coronaviruses in Bat Populations of Georgia.
Urushadze L , Babuadze G , Shi M , Escobar LE , Mauldin MR , Natradeze I , Machablishvili A , Kutateladze T , Imnadze P , Nakazawa Y , Velasco-Villa A . Viruses 2021 14 (1) Mammal-associated coronaviruses have a long evolutionary history across global bat populations, which makes them prone to be the most likely ancestral origins of coronavirus-associated epidemics and pandemics globally. Limited coronavirus research has occurred at the junction of Europe and Asia, thereby investigations in Georgia are critical to complete the coronavirus diversity map in the region. We conducted a cross-sectional coronavirus survey in bat populations at eight locations of Georgia, from July to October of 2014. We tested 188 anal swab samples, remains of previous pathogen discovery studies, for the presence of coronaviruses using end-point pan-coronavirus RT-PCR assays. Samples positive for a 440 bp amplicon were Sanger sequenced to infer coronavirus subgenus or species through phylogenetic reconstructions. Overall, we found a 24.5% positive rate, with 10.1% for Alphacoronavirus and 14.4% for Betacoronavirus. Albeit R. euryale, R. ferrumequinum, M. blythii and M. emarginatus were found infected with both CoV genera, we could not rule out CoV co-infection due to limitation of the sequencing method used and sample availability. Based on phylogenetic inferences and genetic distances at nucleotide and amino acid levels, we found one putative new subgenus and three new species of Alphacoronavirus, and two new species of Betacoronavirus. |
Use of partial N-gene sequences as a tool to monitor progress on rabies control and elimination efforts in Ethiopia.
Binkley L , Deressa A , Shi M , Jara M , Escobar LE , Mauldin MR , Matheny A , O'Quin J , Pieracci EG , Kling C , Hartloge C , Yimer G , Abate E , Gebreyes W , Reynolds M , Belay E , Shiferaw M , Nakazawa Y , Velasco-Villa A . Acta Trop 2021 221 106022 Ethiopia is one of the African countries most affected by rabies. A coarse catalog of rabies viruses (RABV) was created as a benchmark to assess the impact of control and elimination activities. We evaluated a 726 bp amplicon at the end of the N-gene to infer viral lineages in circulation using maximum likelihood and Bayesian methods for phylogenetic reconstruction. We sequenced 228 brain samples from wild and domestic animals collected in five Ethiopian regions during 2010-2017. Results identified co-circulating RABV lineages that are causing recurrent spillover infections into wildlife and domestic animals. We found no evidence of importation of RABVs from other African countries or vaccine-induced cases in the area studied. A divergent RABV lineage might be involved in an independent rabies cycle in jackals. This investigation provides a feasible approach to assess rabies control and elimination efforts in resource-limited countries. |
Educational Approach to Prevent the Burden of Vaccinia Virus Infections in a Bovine Vaccinia Endemic Area in Brazil
Barbosa Costa G , Silva de Oliveira J , Townsend MB , Carson WC , Borges IA , McCollum AM , Kroon EG , Satheshkumar PS , Reynolds MG , Nakazawa YJ , de Souza Trindade G . Pathogens 2021 10 (5) Bovine vaccinia (BV), caused by Vaccinia virus (VACV), is a zoonotic disease characterized by exanthematous lesions on the teats of dairy cows and the hands of milkers, and is an important public health issue in Brazil and South America. BV also results in economic losses to the dairy industry, being a burden to the regions involved in milk production. In the past 20 years, much effort has been made to increase the knowledge regarding BV epidemiology, etiologic agents, and interactions with the hosts and the environment. In the present study, we evaluated milking practices that could be associated with VACV infections in an endemic area in Brazil and proposed an educational tool to help prevent VACV infections. In our survey, 124 individuals (51.7%) from a total of 240 had previously heard of BV, 94 of which knew about it through BV outbreaks. Although most individuals involved in dairy activities (n = 85/91) reported having good hygiene practices, only 29.7% used adequate disinfecting products to clean their hands and 39.5% disinfected cows' teats before and after milking. Furthermore, 46.7% of individuals reported having contact with other farm and domestic animals besides dairy cattle. We also evaluated the presence of IgG and IgM antibodies in the surveyed population. Overall, 6.1% of likely unvaccinated individuals were positive for anti-Orthopoxvirus IgG antibodies, and 1.7% of all individuals were positive for IgM antibodies. Based on our findings, we proposed educational materials which target individuals with permanent residence in rural areas (mainly farmers and milkers), providing an overview and basic information about preventive measures against VACV infections that could enhance BV control and prevention efforts, especially for vulnerable populations located in endemic areas. |
SARS-CoV-2 transmission in a Georgia school district - United States, December 2020-January 2021.
Gettings JR , Gold JAW , Kimball A , Forsberg K , Scott C , Uehara A , Tong S , Hast M , Swanson MR , Morris E , Oraka E , Almendares O , Thomas ES , Mehari L , McCloud J , Roberts G , Crosby D , Balajee A , Burnett E , Chancey RJ , Cook P , Donadel M , Espinosa C , Evans ME , Fleming-Dutra KE , Forero C , Kukielka EA , Li Y , Marcet PL , Mitruka K , Nakayama JY , Nakazawa Y , O'Hegarty M , Pratt C , Rice ME , Rodriguez Stewart RM , Sabogal R , Sanchez E , Velasco-Villa A , Weng MK , Zhang J , Rivera G , Parrott T , Franklin R , Memark J , Drenzek C , Hall AJ , Kirking HL , Tate JE , Vallabhaneni S . Clin Infect Dis 2021 74 (2) 319-326 BACKGROUND: To inform prevention strategies, we assessed the extent of SARS-CoV-2 transmission and settings in which transmission occurred in a Georgia public school district. METHODS: During December 1, 2020-January 22, 2021, SARS-CoV-2-infected index cases and their close contacts in schools were identified by school and public health officials. For in-school contacts, we assessed symptoms and offered SARS-CoV-2 RT-PCR testing; performed epidemiologic investigations and whole-genome sequencing to identify in-school transmission; and calculated secondary attack rate (SAR) by school setting (e.g., sports, elementary school classroom), index case role (i.e., staff, student), and index case symptomatic status. RESULTS: We identified 86 index cases and 1,119 contacts, 688 (63.1%) of whom received testing. Fifty-nine (8.7%) of 679 contacts tested positive; 15 (17.4%) of 86 index cases resulted in ≥2 positive contacts. Among 55 persons testing positive with available symptom data, 31 (56.4%) were asymptomatic. Highest SAR were in indoor, high-contact sports settings (23.8%, 95% confidence interval [CI] 12.7, 33.3), staff meetings/lunches (18.2%, CI 4.5-31.8), and elementary school classrooms (9.5%, CI 6.5-12.5). SAR was higher for staff (13.1%, CI 9.0-17.2) versus student index cases (5.8%, CI 3.6-8.0) and for symptomatic (10.9%, CI 8.1-13.9) versus asymptomatic index cases (3.0%, CI 1.0-5.5). CONCLUSIONS: Indoor sports may pose a risk to the safe operation of in-person learning. Preventing infection in staff members, through measures that include COVID-19 vaccination, is critical to reducing in-school transmission. Because many positive contacts were asymptomatic, contact tracing should be paired with testing, regardless of symptoms. |
Geographic distribution and genetic characterization of poxviruses from human infections in Georgia, 2009-2014.
Khmaladze E , Mauldin MR , Tsaguria D , Gavashelidze M , Sidamonidze K , Tevdoradze T , Li Y , Reynolds MG , Imnadze P , Nakazawa Y . Arch Virol 2021 166 (6) 1729-1733 Anthrax is endemic in Georgia, as are multiple zoonotic poxviruses. Poxvirus-associated infections share some clinical manifestations and exposure risks with anthrax, and so it is important to distinguish between the two. With this in mind, an archived collection of anthrax-negative DNA samples was retrospectively screened for poxviruses, and of the 148 human samples tested, 64 were positive. Sequence analysis confirmed the presence of orf virus, bovine papular stomatitis virus, and pseudocowpox virus. This study provides evidence of previously unrecognized poxvirus infections in Georgia and highlights the benefit of the timely identification of such infections by improving laboratory capacity. |
Low SARS-CoV-2 Transmission in Elementary Schools - Salt Lake County, Utah, December 3, 2020-January 31, 2021.
Hershow RB , Wu K , Lewis NM , Milne AT , Currie D , Smith AR , Lloyd S , Orleans B , Young EL , Freeman B , Schwartz N , Bryant B , Espinosa C , Nakazawa Y , Garza E , Almendares O , Abara WE , Ehlman DC , Waters K , Hill M , Risk I , Oakeson K , Tate JE , Kirking HL , Dunn A , Vallabhaneni S , Hersh AL , Chu VT . MMWR Morb Mortal Wkly Rep 2021 70 (12) 442-448 School closures affected more than 55 million students across the United States when implemented as a strategy to prevent the transmission of SARS-CoV-2, the virus that causes COVID-19 (1). Reopening schools requires balancing the risks for SARS-CoV-2 infection to students and staff members against the benefits of in-person learning (2). During December 3, 2020-January 31, 2021, CDC investigated SARS-CoV-2 transmission in 20 elementary schools (kindergarten through grade 6) that had reopened in Salt Lake County, Utah. The 7-day cumulative number of new COVID-19 cases in Salt Lake County during this time ranged from 290 to 670 cases per 100,000 persons.(†) Susceptible(§) school contacts(¶) (students and staff members exposed to SARS-CoV-2 in school) of 51 index patients** (40 students and 11 staff members) were offered SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) testing. Among 1,041 susceptible school contacts, 735 (70.6%) were tested, and five of 12 cases identified were classified as school-associated; the secondary attack rate among tested susceptible school contacts was 0.7%. Mask use among students was high (86%), and the median distance between students' seats in classrooms was 3 ft. Despite high community incidence and an inability to maintain ≥6 ft of distance between students at all times, SARS-CoV-2 transmission was low in these elementary schools. The results from this investigation add to the increasing evidence that in-person learning can be achieved with minimal SARS-CoV-2 transmission risk when multiple measures to prevent transmission are implemented (3,4). |
Clinical and epidemiologic findings from enhanced monkeypox surveillance in Tshuapa Province, Democratic Republic of the Congo during 2011-2015
Whitehouse ER , Bonwitt J , Hughes CM , Lushima RS , Likafi T , Nguete B , Kabamba J , Monroe B , Doty JB , Nakazawa Y , Damon I , Malekani J , Davidson W , Wilkins K , Li Y , Radford KW , Schmid DS , Pukuta E , Muyamuna E , Karhemere S , Tamfum JM , Okitolonda EW , McCollum AM , Reynolds MG . J Infect Dis 2021 223 (11) 1870-1878 BACKGROUND: Monkeypox is a poorly described emerging zoonosis endemic to Central and Western Africa. METHODS: Using surveillance data from Tshuapa Province, Democratic Republic of the Congo during 2011-2015, we evaluated differences in incidence, exposures, and clinical presentation of PCR-confirmed cases by sex and age. RESULTS: We report 1,057 confirmed cases. Average annual incidence was 14·1 per 100,000 (95% CI: 13·3-15·0). Incidence was higher in males (incidence rate ratio [IRR] males: females: 1·21, 95% CI 1·07-1·37), except among 20-29-year-old (IRR: 0·70, 95% CI: 0·51-0·95). Females aged 20-29 years also reported a high frequency of exposures (26·2%) to people with monkeypox-like symptoms. Highest incidence was among 10-19-year-old males, the cohort reporting the highest proportion of animal exposures (37·5%). Incidence was lower among those presumed to have received smallpox vaccination versus those presumed unvaccinated. No differences were observed by age group in lesion count or lesion severity score. CONCLUSIONS: Monkeypox incidence was twice that reported during 1980-1985, an increase possibly linked to declining immunity provided by smallpox vaccination. The high proportion of cases attributed to human exposures suggests changing exposure patterns. Cases were distributed across age and sex, suggesting frequent exposures that follow socio-cultural norms. |
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. |
Laboratory infection of novel Akhmeta virus in CAST/EiJ mice
Morgan CN , Matheny AM , Nakazawa YJ , Kling C , Gallardo-Romero N , Seigler L , Barbosa Costa G , Hutson C , Maghlakelidze G , Olson V , Doty JB . Viruses 2020 12 (12) Akhmeta virus is a zoonotic Orthopoxvirus first identified in 2013 in the country of Georgia. Subsequent ecological investigations in Georgia have found evidence that this virus is widespread in its geographic distribution within the country and in its host-range, with rodents likely involved in its circulation in the wild. Yet, little is known about the pathogenicity of this virus in rodents. We conducted the first laboratory infection of Akhmeta virus in CAST/EiJ Mus musculus to further characterize this novel virus. We found a dose-dependent effect on mortality and weight loss (p < 0.05). Anti-orthopoxvirus antibodies were detected in the second- and third-highest dose groups (5 × 10(4) pfu and 3 × 10(2) pfu) at euthanasia by day 10, and day 14 post-infection, respectively. Anti-orthopoxvirus antibodies were not detected in the highest dose group (3 × 10(6) pfu), which were euthanized at day 7 post-infection and had high viral load in tissues, suggesting they succumbed to disease prior to mounting an effective immune response. In order of highest burden, viable virus was detected in the nostril, lung, tail, liver and spleen. All individuals tested in the highest dose groups were DNAemic. Akhmeta virus was highly pathogenic in CAST/EiJ Mus musculus, causing 100% mortality when ≥3 × 10(2) pfu was administered. |
Exportation of Monkeypox virus from the African continent.
Mauldin MR , McCollum AM , Nakazawa YJ , Mandra A , Whitehouse ER , Davidson W , Zhao H , Gao J , Li Y , Doty J , Yinka-Ogunleye A , Akinpelu A , Aruna O , Naidoo D , Lewandowski K , Afrough B , Graham V , Aarons E , Hewson R , Vipond R , Dunning J , Chand M , Brown C , Cohen-Gihon I , Erez N , Shifman O , Israeli O , Sharon M , Schwartz E , Beth-Din A , Zvi A , Mak TM , Ng YK , Cui L , Lin RTP , Olson VA , Brooks T , Paran N , Ihekweazu C , Reynolds MG . J Infect Dis 2020 225 (8) 1367-1376 BACKGROUND: The largest West African monkeypox outbreak began September 2017, in Nigeria. Four individuals traveling from Nigeria to the UK (2), Israel, and Singapore became the first human monkeypox cases exported from Africa, and a related nosocomial transmission event in the UK became the first confirmed human-to-human monkeypox transmission event outside of Africa. METHODS: Epidemiological and molecular data for exported and Nigerian cases were analyzed jointly to better understand the exportations in the temporal and geographic context of the outbreak. RESULTS: Isolates from all travelers and a Bayelsa case shared a most recent common ancestor and traveled to Bayelsa, Delta, or Rivers states. Genetic variation for this cluster was lower than would be expected from a random sampling of genomes from this outbreak, but data did not support direct links between travelers. CONCLUSIONS: Monophyly of exportation cases and the Bayelsa sample, along with the intermediate levels of genetic variation suggest a small pool of related isolates is the likely source for the exported infections. This may be the result of the level of genetic variation present in monkeypox isolates circulating within the contiguous region of Bayelsa, Delta, and Rivers states, or another more restricted, yet unidentified source pool. |
- Page last reviewed:Feb 1, 2024
- Page last updated:Apr 29, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure