Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-23 (of 23 Records) |
Query Trace: Armstrong GL[original query] |
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Cryptic transmission of SARS-CoV-2 in Washington State.
Bedford T , Greninger AL , Roychoudhury P , Starita LM , Famulare M , Huang ML , Nalla A , Pepper G , Reinhardt A , Xie H , Shrestha L , Nguyen TN , Adler A , Brandstetter E , Cho S , Giroux D , Han PD , Fay K , Frazar CD , Ilcisin M , Lacombe K , Lee J , Kiavand A , Richardson M , Sibley TR , Truong M , Wolf CR , Nickerson DA , Rieder MJ , Englund JA , Hadfield J , Hodcroft EB , Huddleston J , Moncla LH , Müller NF , Neher RA , Deng X , Gu W , Federman S , Chiu C , Duchin J , Gautom R , Melly G , Hiatt B , Dykema P , Lindquist S , Queen K , Tao Y , Uehara A , Tong S , MacCannell D , Armstrong GL , Baird GS , Chu HY , Shendure J , Jerome KR . medRxiv 2020 Following its emergence in Wuhan, China, in late November or early December 2019, the SARS-CoV-2 virus has rapidly spread throughout the world. On March 11, 2020, the World Health Organization declared Coronavirus Disease 2019 (COVID-19) a pandemic. Genome sequencing of SARS-CoV-2 strains allows for the reconstruction of transmission history connecting these infections. Here, we analyze 346 SARS-CoV-2 genomes from samples collected between 20 February and 15 March 2020 from infected patients in Washington State, USA. We found that the large majority of SARS-CoV-2 infections sampled during this time frame appeared to have derived from a single introduction event into the state in late January or early February 2020 and subsequent local spread, strongly suggesting cryptic spread of COVID-19 during the months of January and February 2020, before active community surveillance was implemented. We estimate a common ancestor of this outbreak clade as occurring between 18 January and 9 February 2020. From genomic data, we estimate an exponential doubling between 2.4 and 5.1 days. These results highlight the need for large-scale community surveillance for SARS-CoV-2 introductions and spread and the power of pathogen genomics to inform epidemiological understanding. |
Emergence of SARS-CoV-2 B.1.1.7 Lineage - United States, December 29, 2020-January 12, 2021.
Galloway SE , Paul P , MacCannell DR , Johansson MA , Brooks JT , MacNeil A , Slayton RB , Tong S , Silk BJ , Armstrong GL , Biggerstaff M , Dugan VG . MMWR Morb Mortal Wkly Rep 2021 70 (3) 95-99 On December 14, 2020, the United Kingdom reported a SARS-CoV-2 variant of concern (VOC), lineage B.1.1.7, also referred to as VOC 202012/01 or 20I/501Y.V1.* The B.1.1.7 variant is estimated to have emerged in September 2020 and has quickly become the dominant circulating SARS-CoV-2 variant in England (1). B.1.1.7 has been detected in over 30 countries, including the United States. As of January 13, 2021, approximately 76 cases of B.1.1.7 have been detected in 12 U.S. states.(†) Multiple lines of evidence indicate that B.1.1.7 is more efficiently transmitted than are other SARS-CoV-2 variants (1-3). The modeled trajectory of this variant in the U.S. exhibits rapid growth in early 2021, becoming the predominant variant in March. Increased SARS-CoV-2 transmission might threaten strained health care resources, require extended and more rigorous implementation of public health strategies (4), and increase the percentage of population immunity required for pandemic control. Taking measures to reduce transmission now can lessen the potential impact of B.1.1.7 and allow critical time to increase vaccination coverage. Collectively, enhanced genomic surveillance combined with continued compliance with effective public health measures, including vaccination, physical distancing, use of masks, hand hygiene, and isolation and quarantine, will be essential to limiting the spread of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). Strategic testing of persons without symptoms but at higher risk of infection, such as those exposed to SARS-CoV-2 or who have frequent unavoidable contact with the public, provides another opportunity to limit ongoing spread. |
The intersection of genomics and big data with public health: Opportunities for precision public health.
Khoury MJ , Armstrong GL , Bunnell RE , Cyril J , Iademarco MF . PLoS Med 2020 17 (10) e1003373 Muin Khoury and co-authors discuss anticipated contributions of genomics and other forms of large-scale data in public health. |
Cryptic transmission of SARS-CoV-2 in Washington state.
Bedford T , Greninger AL , Roychoudhury P , Starita LM , Famulare M , Huang ML , Nalla A , Pepper G , Reinhardt A , Xie H , Shrestha L , Nguyen TN , Adler A , Brandstetter E , Cho S , Giroux D , Han PD , Fay K , Frazar CD , Ilcisin M , Lacombe K , Lee J , Kiavand A , Richardson M , Sibley TR , Truong M , Wolf CR , Nickerson DA , Rieder MJ , Englund JA , Hadfield J , Hodcroft EB , Huddleston J , Moncla LH , Müller NF , Neher RA , Deng X , Gu W , Federman S , Chiu C , Duchin JS , Gautom R , Melly G , Hiatt B , Dykema P , Lindquist S , Queen K , Tao Y , Uehara A , Tong S , MacCannell D , Armstrong GL , Baird GS , Chu HY , Shendure J , Jerome KR . Science 2020 370 (6516) 571-575 Following its emergence in Wuhan, China, in late November or early December 2019, the SARS-CoV-2 virus has rapidly spread globally. Genome sequencing of SARS-CoV-2 allows reconstruction of its transmission history, although this is contingent on sampling. We have analyzed 453 SARS-CoV-2 genomes collected between 20 February and 15 March 2020 from infected patients in Washington State, USA. We find that most SARS-CoV-2 infections sampled during this time derive from a single introduction in late January or early February 2020 which subsequently spread locally before active community surveillance was implemented. |
Pathogen Genomics in Public Health.
Armstrong GL , MacCannell DR , Taylor J , Carleton HA , Neuhaus EB , Bradbury RS , Posey JE , Gwinn M . N Engl J Med 2019 381 (26) 2569-2580 Rapid advances in DNA sequencing technology ("next-generation sequencing") have inspired optimism about the potential of human genomics for "precision medicine." Meanwhile, pathogen genomics is already delivering "precision public health" through more effective investigations of outbreaks of foodborne illnesses, better-targeted tuberculosis control, and more timely and granular influenza surveillance to inform the selection of vaccine strains. In this article, we describe how public health agencies have been adopting pathogen genomics to improve their effectiveness in almost all domains of infectious disease. This momentum is likely to continue, given the ongoing development in sequencing and sequencing-related technologies. |
Next-Generation Sequencing of Infectious Pathogens.
Gwinn M , MacCannell D , Armstrong GL . JAMA 2019 321 (9) 893-894 Next generation sequencing (NGS) holds potential for improving clinical and public health microbiology.1 In addition to identifying pathogens faster and more precisely, high-throughput technologies and bioinformatics can provide new insights into disease transmission, virulence, and antimicrobial resistance. The US public health system is integrating pathogen genome sequencing into infectious disease surveillance with support from the Advanced Molecular Detection (AMD) program established by Congress at the Centers for Disease Control and Prevention (CDC) in 2014.2 Population-level data on pathogen genomes in turn supports the development of more precise and efficient clinical diagnostics. In time, laboratories may be able to replace many traditional microbiology processes with a single workflow that accommodates a wide array of pathogens.3 |
Human metapneumovirus circulation in the United States, 2008 to 2014
Haynes AK , Fowlkes AL , Schneider E , Mutuc JD , Armstrong GL , Gerber SI . Pediatrics 2016 137 (5) BACKGROUND: Human metapneumovirus (HMPV) infection causes respiratory illness, including bronchiolitis and pneumonia. However, national HMPV seasonality, as it compares with respiratory syncytial virus (RSV) and influenza seasonality patterns, has not been well described. METHODS: Hospital and clinical laboratories reported weekly aggregates of specimens tested and positive detections for HMPV, RSV, and influenza to the National Respiratory and Enteric Virus Surveillance System from 2008 to 2014. A season was defined as consecutive weeks with ≥3% positivity for HMPV and ≥10% positivity for RSV and influenza during a surveillance year (June through July). For each virus, the season, onset, offset, duration, peak, and 6-season medians were calculated. RESULTS: Among consistently reporting laboratories, 33 583 (3.6%) specimens were positive for HMPV, 281 581 (15.3%) for RSV, and 401 342 (18.2%) for influenza. Annually, 6 distinct HMPV seasons occurred from 2008 to 2014, with onsets ranging from November to February and offsets from April to July. Based on the 6-season medians, RSV, influenza, and HMPV onsets occurred sequentially and season durations were similar at 21 to 22 weeks. HMPV demonstrated a unique biennial pattern of early and late seasonal onsets. RSV seasons (onset, offset, peak) were most consistent and occurred before HMPV seasons. There were no consistent patterns between HMPV and influenza circulations. CONCLUSIONS: HMPV circulation begins in winter and lasts until spring and demonstrates distinct seasons each year, with the onset beginning after that of RSV. HMPV, RSV, and influenza can circulate simultaneously during the respiratory season. |
Possible eradication of wild poliovirus type 3 - worldwide, 2012
Kew OM , Cochi SL , Jafari HS , Wassilak SG , Mast EE , Diop OM , Tangermann RH , Armstrong GL . MMWR Morb Mortal Wkly Rep 2014 63 (45) 1031-1033 In 1988, the World Health Assembly resolved to eradicate polio worldwide. Since then, four of the six World Health Organization (WHO) regions have been certified as polio-free: the Americas in 1994, the Western Pacific Region in 2000, the European Region in 2002, and the South-East Asia Region in 2014. Currently, nearly 80% of the world's population lives in areas certified as polio-free. Certification may be considered when ≥3 years have passed since the last isolation of wild poliovirus (WPV) in the presence of sensitive, certification-standard surveillance. Although regional eradication has been validated in the European Region and the Western Pacific Region, outbreaks resulting from WPV type 1 (WPV1) imported from known endemic areas were detected and controlled in these regions in 2010 and 2011, respectively. The last reported case associated with WPV type 2 (WPV2) was in India in 1999, marking global interruption of WPV2 transmission. The completion of polio eradication was declared a programmatic emergency for public health in 2012, and the international spread of WPV1 was declared a public health emergency of international concern in May 2014. The efforts needed to interrupt all indigenous WPV1 transmission are now being focused on the remaining endemic countries: Nigeria, Afghanistan, and Pakistan. WPV type 3 (WPV3) has not been detected in circulation since November 11, 2012. This report summarizes the evidence of possible global interruption of transmission of WPV3, based on surveillance for acute flaccid paralysis (AFP) and environmental surveillance. |
Progress toward global interruption of wild poliovirus transmission, 2010-2013, and tackling the challenges to complete eradication
Wassilak SG , Oberste MS , Tangermann RH , Diop OM , Jafari HS , Armstrong GL . J Infect Dis 2014 210 Suppl 1 S5-s15 Despite substantial progress, global polio eradication has remained elusive. Indigenous wild poliovirus (WPV) transmission in 4 endemic countries (Afghanistan, India, Nigeria, and Pakistan) persisted into 2010 and outbreaks from imported WPV continued. By 2013, most outbreaks in the interim were promptly controlled. The number of polio-affected districts globally has declined by 74% (from 481 in 2009 to 126 in 2013), including a 79% decrease in the number of affected districts in endemic countries (from 304 to 63). India is now polio-free. The challenges to success in the remaining polio-endemic countries include (1) threats to the security of vaccinators in each country and a ban on polio vaccination in areas of Afghanistan and Pakistan; (2) a risk of decreased government commitment; and (3) remaining surveillance gaps. Coordinated efforts under the International Health Regulations and efforts to mitigate the challenges provide a clear opportunity to soon secure global eradication. |
A world without polio
Cochi SL , Jafari HS , Armstrong GL , Sutter RW , Linkins RW , Pallansch MA , Kew O , Aylward RB . J Infect Dis 2014 210 Suppl 1 S1-4 When this journal last published a special supplement on polio nearly 18 years ago, we lived in a world that was still deeply entangled with this devastating virus [1]. All 3 poliovirus serotypes were still circulating on four continents. Some of the world’s largest countries remained mired in the disease, some with thousands of cases each year. Most tellingly, a number of polio-infected countries, particularly in Africa, had not even introduced core eradication strategies, such as polio national immunization days (NIDs). Both financial and human resources were stretched; worldwide, <250 people were employed full time in a program whose success would eventually require, at its peak, reaching and vaccinating >600 million children multiple times per year. | Despite these realities, optimism and enthusiasm were running high in 1997. Nelson Mandela himself had, just the previous year, launched the continent-wide Polio-Free Africa initiative accompanied by a Kick Polio Out of Africa social mobilization campaign. The massive Operation MECACAR was rapidly clearing virus from the 18 participating countries, spanning 2 continents and coordinating and collaborating through shared poliovirus surveillance, cross-border planning, and synchronized NIDs across the Middle East, Caucasus, Central Asian Republics, and Russian Federation. And in most of the world where the 4 core eradication strategies had been introduced, the number of both cases of polio-paralyzed children and polio-infected countries were falling rapidly (Figure 1). The sense that, with further program expansion, eradication might soon be inevitable was reinforced in 1999 by the eradication of the type 2 wild poliovirus serotype globally; that the last type 2 case was reported from Aligarh, India, suggested that eradication of the other serotypes would follow quickly, both in that country and globally. By 2000, 3 of the 6 regions of the World Health Organization (WHO) had seen their last indigenous poliovirus and were either already certified as polio free or soon would be. Although it was apparent that the original goal of completing wild poliovirus eradication globally by 2000 would be missed, the then Secretary-General of the United Nations, Mr Kofi Annan, convened a special Polio Eradication Summit in September of that year to ensure that the program remained on track for its secondary target of certification of global eradication in 2005. By 2001, polio had been reduced to 475 cases in 10 polio-endemic countries, compared with 350 000 cases in 125 polio-endemic countries in 1988. |
Elimination of endemic measles, rubella, and congenital rubella syndrome from the Western hemisphere: the US experience.
Papania MJ , Wallace GS , Rota PA , Icenogle JP , Fiebelkorn AP , Armstrong GL , Reef SE , Redd SB , Abernathy ES , Barskey AE , Hao L , McLean HQ , Rota JS , Bellini WJ , Seward JF . JAMA Pediatr 2013 168 (2) 148-55 IMPORTANCE: To verify the elimination of endemic measles, rubella, and congenital rubella syndrome (CRS) from the Western hemisphere, the Pan American Health Organization requested each member country to compile a national elimination report. The United States documented the elimination of endemic measles in 2000 and of endemic rubella and CRS in 2004. In December 2011, the Centers for Disease Control and Prevention convened an external expert panel to review the evidence and determine whether elimination of endemic measles, rubella, and CRS had been sustained. OBJECTIVE: To review the evidence for sustained elimination of endemic measles, rubella, and CRS from the United States through 2011. DESIGN, SETTING, AND PARTICIPANTS: Review of data for measles from 2001 to 2011 and for rubella and CRS from 2004 to 2011 covering the US resident population and international visitors, including disease epidemiology, importation status of cases, molecular epidemiology, adequacy of surveillance, and population immunity as estimated by national vaccination coverage and serologic surveys. MAIN OUTCOMES AND MEASURES: Annual numbers of measles, rubella, and CRS cases, by importation status, outbreak size, and distribution; proportions of US population seropositive for measles and rubella; and measles-mumps-rubella vaccination coverage levels. RESULTS: Since 2001, US reported measles incidence has remained below 1 case per 1 000 000 population. Since 2004, rubella incidence has been below 1 case per 10 000 000 population, and CRS incidence has been below 1 case per 5 000 000 births. Eighty-eight percent of measles cases and 54% of rubella cases were internationally imported or epidemiologically or virologically linked to importation. The few cases not linked to importation were insufficient to represent endemic transmission. Molecular epidemiology indicated no endemic genotypes. The US surveillance system is adequate to detect endemic measles or rubella. Seroprevalence and vaccination coverage data indicate high levels of population immunity to measles and rubella. CONCLUSIONS AND RELEVANCE: The external expert panel concluded that the elimination of endemic measles, rubella, and CRS from the United States was sustained through 2011. However, international importation continues, and health care providers should suspect measles or rubella in patients with febrile rash illness, especially when associated with international travel or international visitors, and should report suspected cases to the local health department. |
Neurologic manifestations associated with an outbreak of typhoid fever, Malawi - Mozambique, 2009: an epidemiologic investigation
Sejvar J , Lutterloh E , Naiene J , Likaka A , Manda R , Nygren B , Monroe S , Khaila T , Lowther SA , Capewell L , Date K , Townes D , Redwood Y , Schier J , Barr BT , Demby A , Mallewa M , Kampondeni S , Blount B , Humphrys M , Talkington D , Armstrong GL , Mintz E . PLoS One 2012 7 (12) e46099 BACKGROUND: The bacterium Salmonella enterica serovar Typhi causes typhoid fever, which is typically associated with fever and abdominal pain. An outbreak of typhoid fever in Malawi-Mozambique in 2009 was notable for a high proportion of neurologic illness. OBJECTIVE: Describe neurologic features complicating typhoid fever during an outbreak in Malawi-Mozambique METHODS: Persons meeting a clinical case definition were identified through surveillance, with laboratory confirmation of typhoid by antibody testing or blood/stool culture. We gathered demographic and clinical information, examined patients, and evaluated a subset of patients 11 months after onset. A sample of persons with and without neurologic signs was tested for vitamin B6 and B12 levels and urinary thiocyanate. RESULTS: Between March - November 2009, 303 cases of typhoid fever were identified. Forty (13%) persons had objective neurologic findings, including 14 confirmed by culture/serology; 27 (68%) were hospitalized, and 5 (13%) died. Seventeen (43%) had a constellation of upper motor neuron findings, including hyperreflexia, spasticity, or sustained ankle clonus. Other neurologic features included ataxia (22, 55%), parkinsonism (8, 20%), and tremors (4, 10%). Brain MRI of 3 (ages 5, 7, and 18 years) demonstrated cerebral atrophy but no other abnormalities. Of 13 patients re-evaluated 11 months later, 11 recovered completely, and 2 had persistent hyperreflexia and ataxia. Vitamin B6 levels were markedly low in typhoid fever patients both with and without neurologic signs. CONCLUSIONS: Neurologic signs may complicate typhoid fever, and the diagnosis should be considered in persons with acute febrile neurologic illness in endemic areas. |
Impact of a third dose of measles-mumps-rubella vaccine on a mumps outbreak
Ogbuanu IU , Kutty PK , Hudson JM , Blog D , Abedi GR , Goodell S , Lawler J , McLean HQ , Pollock L , Rausch-Phung E , Schulte C , Valure B , Armstrong GL , Gallagher K . Pediatrics 2012 130 (6) e1567-74 BACKGROUND AND OBJECTIVE: During 2009-2010, a northeastern US religious community experienced a large mumps outbreak despite high 2-dose measles-mumps-rubella (MMR) vaccine coverage. A third dose of MMR vaccine was offered to students in an affected community in an effort to control the outbreak. METHODS: Eligible sixth- to 12th-grade students in 3 schools were offered a third dose of MMR vaccine. Baseline and follow-up surveys and physician case reports were used to monitor mumps attack rates (ARs). We calculated ARs for defined 3-week periods before and after the intervention. RESULTS: Of 2265 eligible students, 2178 (96.2%) provided documentation of having received 2 previous doses of MMR vaccine, and a high proportion (1755 or 80.6%) chose to receive an additional vaccine dose. The overall AR for all sixth- to 12th-grade students declined from 4.93% in the prevaccination period to 0.13% after vaccination (P < .001). Villagewide, overall AR declined by 75.6% after the intervention. A decline occurred in all age groups but was significantly greater (96.0%) among 11- to 17-year-olds, the age group targeted for vaccination, than among all other age groups. The proportions of adverse events reported were lower than or within the range of those in previous reports of first- and second-dose MMR vaccine studies. CONCLUSIONS: This is the first study to assess the impact of a third MMR vaccine dose for mumps outbreak control. The decline in incidence shortly after the intervention suggests that a third dose of MMR vaccine may help control mumps outbreaks among populations with preexisting high 2-dose vaccine coverage. |
An outbreak of wild poliovirus in the Republic of Congo, 2010 - 2011
Patel MK , Konde MK , Didi-Ngossaki BH , Ndinga E , Yogolelo R , Salla M , Shaba K , Everts J , Armstrong GL , Daniels D , Burns C , Wassilak S , Pallansch M , Kretsinger K . Clin Infect Dis 2012 55 (10) 1291-8 BACKGROUND: The Republic of Congo has had no cases of wild poliovirus type 1 (WPV1) since 2000. In October 2010, a neurologist noted an abnormal number of cases of acute flaccid paralysis (AFP) among adults which were later confirmed to be caused by WPV1. METHODS: Those presenting with AFP underwent clinical history, physical examination, and clinical specimen collection to determine if they had polio. AFP cases were classified as laboratory-confirmed, clinical, or non-polio AFP. Epidemiologic features of the outbreak were analyzed. RESULTS: From September 19, 2010 to January 22, 2011, 445 WPV1 cases were reported in the ROC; 390 cases were from Pointe Noire. Overall, 331 cases were among adults; 378 cases were clinically confirmed and 64 cases were laboratory confirmed. The case fatality ratio (CFR) was 43%. Epidemiologic characteristics differed among polio cases reported in Pointe Noire and cases reported in the rest of ROC, including age distribution and CFR. The outbreak stopped after multiple vaccination rounds with oral poliovirus vaccine which targeted the entire population. CONCLUSIONS: This outbreak underscores the need to maintain high vaccination coverage to prevent outbreaks, the need to maintain timely high quality surveillance to rapidly identify and respond to any potential cases before an outbreak escalates, and the need to perform ongoing risk assessments of immunity gaps in polio-free countries. |
Respiratory syncytial virus in Indonesian children
Armstrong GL . Pediatr Infect Dis J 2012 31 (5) 539 Globally, respiratory syncytial virus (RSV) is estimated to cause between 66,000 and 199,000 deaths among young children every year.1 Several factors, including a better understanding of RSV disease burden, improvements and vaccine technology and the remarkable success of vaccines such as rotavirus vaccines, have led to a renaissance in interest in RSV vaccine development. Currently, there are more than a dozen RSV vaccine candidates in preclinical or early clinical development. | One of the critical questions about RSV vaccines is whether they can be effective early enough in life to prevent the most severe disease. Studies in industrialized as well as developing nations suggest that the highest incidence of hospitalization for RSV is in the first 6 months of life, and in particular, during the second and third month of life.2–5 Developing vaccines to induce active immunity at such a young age would be challenging. | The study by Simões et al6 in September’s Pediatric Infectious Disease Journal presents an intriguing finding from a study conducted in Indonesia a decade earlier—that fewer than 5% of cases of RSV lower respiratory infection among periurban and semirural Sundanese infants occur in the first 6 months of life. If true, and if this pattern occurs in other developing world settings, this opens the possibility that an RSV vaccine that does not become effective until age 6 months could prevent the bulk of serious RSV-related disease in those settings. |
Trends in the risk of U.S. polio outbreaks and poliovirus vaccine availability for response
Thompson KM , Wallace GS , Tebbens RJ , Smith PJ , Barskey AE , Pallansch MA , Gallagher KM , Alexander JP , Armstrong GL , Cochi SL , Wassilak SG . Public Health Rep 2012 127 (1) 23-37 OBJECTIVES: The United States eliminated indigenous wild polioviruses (WPVs) in 1979 and switched to inactivated poliovirus vaccine in 2000, which quickly ended all indigenous live poliovirus transmission. Continued WPV circulation and use of oral poliovirus vaccine globally allow for the possibility of reintroduction of these viruses. We evaluated the risk of a U.S. polio outbreak and explored potential vaccine needs for outbreak response. METHODS: We synthesized information available on vaccine coverage, exemptor populations, and population immunity. We used an infection transmission model to explore the potential dynamics of a U.S. polio outbreak and potential vaccine needs for outbreak response, and assessed the impacts of heterogeneity in population immunity for two different subpopulations with potentially low coverage. RESULTS: Although the risk of poliovirus introduction remains real, widespread transmission of polioviruses appears unlikely in the U.S., given high routine coverage. However, clusters of un- or underimmunized children might create pockets of susceptibility that could potentially lead to one or more paralytic polio cases. We found that the shift toward combination vaccine utilization, with limited age indications for use, and other current trends (e.g., decreasing proportion of the population with immunity induced by live polioviruses and aging of vaccine exemptor populations) might increase the vulnerability to poliovirus reintroduction at the same time that the ability to respond may decrease. CONCLUSIONS: The U.S. poliovirus vaccine stockpile remains an important resource that may potentially be needed in the future to respond to an outbreak if a live poliovirus gets imported into a subpopulation with low vaccination coverage. |
Multidrug-resistant typhoid fever with neurologic findings on the Malawi-Mozambique border
Lutterloh E , Likaka A , Sejvar J , Manda R , Naiene J , Monroe SS , Khaila T , Chilima B , Mallewa M , Kampondeni SD , Lowther SA , Capewell L , Date K , Townes D , Redwood Y , Schier JG , Nygren B , Tippett Barr B , Demby A , Phiri A , Lungu R , Kaphiyo J , Humphrys M , Talkington D , Joyce K , Stockman LJ , Armstrong GL , Mintz E . Clin Infect Dis 2012 54 (8) 1100-6 BACKGROUND: Salmonella enterica serovar Typhi causes an estimated 22 million cases of typhoid fever and 216,000 deaths annually worldwide. We investigated an outbreak of unexplained febrile illnesses with neurologic findings, determined to be typhoid fever, along the Malawi-Mozambique border. METHODS: The investigation included active surveillance, interviews, examinations of ill and convalescent persons, medical chart reviews, and laboratory testing. Classification as a suspected case required fever and ≥1 other finding (eg, headache or abdominal pain); a probable case required fever and a positive rapid immunoglobulin M antibody test for typhoid (TUBEX TF); a confirmed case required isolation of Salmonella Typhi from blood or stool. Isolates underwent antimicrobial susceptibility testing and subtyping by pulsed-field gel electrophoresis (PFGE). RESULTS: We identified 303 cases from 18 villages with onset during March-November 2009; 214 were suspected, 43 were probable, and 46 were confirmed cases. Forty patients presented with focal neurologic abnormalities, including a constellation of upper motor neuron signs (n=19), ataxia (n=22), and parkinsonism (n=8). Eleven patients died. All 42 isolates tested were resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole; 4 were also resistant to nalidixic acid. Thirty-five of 42 isolates were indistinguishable by PFGE. CONCLUSIONS: The unusual neurologic manifestations posed a diagnostic challenge that was resolved through rapid typhoid antibody testing in the field and subsequent blood culture confirmation in the Malawi national reference laboratory. Extending laboratory diagnostic capacity, including blood culture, to populations at risk for typhoid fever in Africa will improve outbreak detection, response, and clinical treatment. |
Outbreak of lower respiratory tract illness associated with human enterovirus 68 among American Indian children
Jacobson LM , Redd JT , Schneider E , Lu X , Chern SW , Oberste MS , Erdman DD , Fischer GE , Armstrong GL , Kodani M , Montoya J , Magri JM , Cheek JE . Pediatr Infect Dis J 2012 31 (3) 309-12 Human enterovirus 68 (EV68) infections are rarely reported. We describe a respiratory outbreak associated with EV68 among 18 children admitted to a remote Indian Health Service facility during August 11-September 14, 2010. Clinical illness was characterized by pneumonia and wheezing. EV68 should be considered as an etiology in outbreaks of lower respiratory tract illness. |
Persistence of long-term immunity to hepatitis B among adolescents immunized at birth
Chaves SS , Fischer G , Groeger J , Patel PR , Thompson ND , Teshale EH , Stevenson K , Yano VM , Armstrong GL , Samandari T , Kamili S , Drobeniuc J , Hu DJ . Vaccine 2012 30 (9) 1644-9 The long-term duration of recombinant hepatitis B vaccine-induced immunity among persons vaccinated starting at birth is still not well understood. Waning of vaccine-induced immunity could leave young adults at risk of hepatitis B virus infection due to behavioral or occupational exposures. We followed a cohort of children immunized starting at birth with a 3-dose regimen of recombinant hepatitis B vaccine (5mcg, 2.5mcg, 2.5mcg). They were challenged with a booster dose of the hepatitis B vaccine 10 and 15 years after vaccination to assess anamnestic response as a measure of persistence of protection. Among 108 participants who had lost protective antibody levels against hepatitis B, the majority (>70%) had an anamnestic response to the booster dose; response rates did not decline significantly between 10 and 15 years follow-up periods. A high antibody concentration following primary vaccination was independently associated with an anamnestic response later on in life. Nonetheless, approximately 20-30% of participants were unable to mount an immune response after boosting. Hepatitis B revaccination might be required for persons vaccinated starting at birth if opportunities for hepatitis B virus exposure exist. Future vaccine recommendations should be based on studies ascertaining protection against clinically significant disease. |
Malaria in Kakuma refugee camp, Turkana, Kenya: facilitation of Anopheles arabiensis vector populations by installed water distribution and catchment systems
Nabie Bayoh M , Akhwale W , Ombok M , Sang D , Engoki SC , Koros D , Walker ED , Williams HA , Burke H , Armstrong GL , Cetron MS , Weinberg M , Breiman R , Hamel MJ . Malar J 2011 10 149 BACKGROUND: Malaria is a major health concern for displaced persons occupying refugee camps in sub-Saharan Africa, yet there is little information on the incidence of infection and nature of transmission in these settings. Kakuma Refugee Camp, located in a dry area of north-western Kenya, has hosted ca. 60,000 to 90,000 refugees since 1992, primarily from Sudan and Somalia. The purpose of this study was to investigate malaria prevalence and attack rate and sources of Anopheles vectors in Kakuma refugee camp, in 2005-2006, after a malaria epidemic was observed by staff at camp clinics. METHODS: Malaria prevalence and attack rate was estimated from cases of fever presenting to camp clinics and the hospital in August 2005, using rapid diagnostic tests and microscopy of blood smears. Larval habitats of vectors were sampled and mapped. Houses were sampled for adult vectors using the pyrethrum knockdown spray method, and mapped. Vectors were identified to species level and their infection with Plasmodium falciparum determined. RESULTS: Prevalence of febrile illness with P. falciparum was highest among the 5 to 17 year olds (62.4%) while malaria attack rate was highest among the two to 4 year olds (5.2/1,000/day). Infected individuals were spatially concentrated in three of the 11 residential zones of the camp. The indoor densities of Anopheles arabiensis, the sole malaria vector, were similar during the wet and dry seasons, but were distributed in an aggregated fashion and predominantly in the same zones where malaria attack rates were high. Larval habitats and larval populations were also concentrated in these zones. Larval habitats were man-made pits of water associated with tap-stands installed as the water delivery system to residents with year round availability in the camp. Three percent of A. arabiensis adult females were infected with P. falciparum sporozoites in the rainy season. CONCLUSIONS: Malaria in Kakuma refugee camp was due mainly to infection with P. falciparum and showed a hyperendemic age-prevalence profile, in an area with otherwise low risk of malaria given prevailing climate. Transmission was sustained by A. arabiensis, whose populations were facilitated by installation of man-made water distribution and catchment systems. |
Health care-associated measles outbreak in the United States after an importation: challenges and economic impact
Chen SY , Anderson S , Kutty PK , Lugo F , McDonald M , Rota PA , Ortega-Sanchez IR , Komatsu K , Armstrong GL , Sunenshine R , Seward JF . J Infect Dis 2011 203 (11) 1517-25 BACKGROUND: On 12 February 2008, an infected Swiss traveler visited hospital A in Tucson, Arizona, and initiated a predominantly health care-associated measles outbreak involving 14 cases. We investigated risk factors that might have contributed to health care-associated transmission and assessed outbreak-associated hospital costs. METHODS: Epidemiologic data were obtained by case interviews and review of medical records. Health care personnel (HCP) immunization records were reviewed to identify non-measles-immune HCP. Outbreak-associated costs were estimated from 2 hospitals. RESULTS: Of 14 patients with confirmed cases, 7 (50%) were aged ≥18 years, 4 (29%) were hospitalized, 7 (50%) acquired measles in health care settings, and all (100%) were unvaccinated or had unknown vaccination status. Of the 11 patients (79%) who had accessed health care services while infectious, 1 (9%) was masked and isolated promptly after rash onset. HCP measles immunity data from 2 hospitals confirmed that 1776 (25%) of 7195 HCP lacked evidence of measles immunity. Among these HCPs, 139 (9%) of 1583 tested seronegative for measles immunoglobulin G, including 1 person who acquired measles. The 2 hospitals spent US$799,136 responding to and containing 7 cases in these facilities. CONCLUSIONS: Suspecting measles as a diagnosis, instituting immediate airborne isolation, and ensuring rapidly retrievable measles immunity records for HCPs are paramount in preventing health care-associated spread and in minimizing hospital outbreak-response costs. (See the editorial commentary by Ostroff, on pages 1507-9.) |
Non-pharmaceutical interventions during an outbreak of 2009 pandemic influenza A (H1N1) virus infection at a large public university, April-May 2009
Mitchell T , Dee DL , Phares CR , Lipman HB , Gould LH , Kutty P , Desai M , Guh A , Iuliano AD , Silverman P , Siebold J , Armstrong GL , Swerdlow DL , Massoudi MS , Fishbein DB . Clin Infect Dis 2011 52 S138-S145 Nonpharmaceutical interventions (NPIs), such as home isolation, social distancing, and infection control measures, are recommended by public health agencies as strategies to mitigate transmission during influenza pandemics. However, NPI implementation has rarely been studied in large populations. During an outbreak of 2009 Pandemic Influenza A (H1N1) virus infection at a large public university in April 2009, an online survey was conducted among students, faculty, and staff to assess knowledge of and adherence to university-recommended NPI. Although 3924 (65%) of 6049 student respondents and 1057 (74%) of 1401 faculty respondents reported increased use of self-protective NPI, such as hand washing, only 27 (6.4%) of 423 students and 5 (8.6%) of 58 faculty with acute respiratory infection (ARI) reported staying home while ill. Nearly one-half (46%) of student respondents, including 44.7% of those with ARI, attended social events. Results indicate a need for efforts to increase compliance with home isolation and social distancing measures. |
Timely assessment of the severity of the 2009 H1N1 influenza pandemic
Armstrong GL , Brammer L , Finelli L . Clin Infect Dis 2011 52 S83-S89 During the 2009 influenza pandemic, weekly mortality data were analyzed to estimate excess mortality above a seasonally adjusted baseline modeled from prior years' data. Between the 1962-1963 and 2008-2009 seasons, among persons ≥25 years old, excess mortality had been substantially higher during influenza A(H3N2)-dominant years than during A(H1N1)-dominant years. Among persons ≥15 years of age, excess mortality was higher in the 1968-1969 influenza pandemic season than during any other season. During the 2009-2010 pandemic, among all age groups 65 years old, excess mortality increased earlier than during any of the previous 47 seasons, eventually exceeding mortality in any prior non-pandemic season. In the ≥65-year-old age group, excess mortality remained relatively low, at rates typical of seasonal influenza A(H1N1) seasons. The model provided a timely assessment of severity during the 2009-2010 influenza pandemic, showing that, compared with prior seasons, mortality was relatively high among persons 65 years old and relatively low among those ≥65 years old. |
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