Olga Kosoy

Centers for Disease Control and Prevention, Атланта, Michigan, United States

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Publications (28)200.09 Total impact

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    ABSTRACT: Yellow fever virus (YFV) is endemic in tropical and sub-tropical regions of the world, with around 180,000 human infections a year occurring in Africa. Serologic testing is the chief laboratory diagnostic means of identifying an outbreak and to inform the decision to commence a vaccination campaign. The World Health Organization disseminates the reagents for YFV testing to African reference laboratories, and the US Centers for Disease Control and Prevention (CDC) is charged with producing and providing these reagents. The CDC M-antibody capture ELISA is a 2-day test, requiring titration of reagents when new lots are received, which leads to inconsistency in testing and wastage of material. Here we describe the development of a kit-based assay (YF MAC-HD) based upon the CDC method, that is completed in approximately 3.5h, with equivocal samples being reflexed to an overnight protocol. The kit exhibits >90% accuracy when compared to the 2-day test. The kits were designed for use with a minimum of equipment and are stored at 4°C, removing the need for freezing capacity. This kit is capable of tolerating temporary sub-optimal storage conditions which will ease shipping or power outage concerns, and a shelf life of >6 months was demonstrated with no deterioration in accuracy. All reagents necessary to run the YF MAC-HD are included in the kit and are single-use, with 8 or 24 sample options per kit. Field trials are envisioned for the near future, which will enable refinement of the method. The use of the YF MAC-HD is anticipated to reduce materials wastage, and improve the quality and consistency of YFV serologic testing in endemic areas.
    Journal of virological methods 09/2015; DOI:10.1016/j.jviromet.2015.08.025 · 1.78 Impact Factor
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    ABSTRACT: We examined sera from snowshoe hares (Lepus americanus) livetrapped in the northern Greater Yellowstone Area (GYA), US, for antibodies to Brucella abortus, Francisella tularensis, and snowshoe hare virus (SSHV). Zero of 90, 0 of 67, and 40 of 100 samples were antibody positive for B. abortus, F. tularensis, and SSHV, respectively. Hares were trapped from 2009 to 2012, and of the six animals that were captured twice with at least 1 yr between captures, four developed antibody to SSHV, indicating active exposure to the agent. These findings suggest snowshoe hares in the GYA do not play a significant role as a reservoir of B. abortus, but do maintain the zoonotic, encephalitic SSHV in the population.
    Journal of wildlife diseases 07/2015; 51(3):769-773. DOI:10.7589/2015-01-021 · 1.36 Impact Factor
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    ABSTRACT: Chikungunya virus is an emerging threat to the United States because humans are amplifying hosts and competent mosquito vectors are present in many regions of the country. We identified laboratory-confirmed chikungunya virus infections with diagnostic testing performed in the United States from 2010 to 2013. We described the epidemiology of these cases and determined which were reported to ArboNET. From 2010 to 2013, 115 laboratory-confirmed chikungunya virus infections were identified. Among 55 cases with known travel history, 53 (96%) reported travel to Asia and 2 (4%) to Africa. No locally acquired infections were identified. Six patients had detectable viremia after returning to the United States. Only 21% of identified cases were reported to ArboNET, with a median of 72 days between illness onset and reporting. Given the risk of introduction into the United States, healthcare providers and public health officials should be educated about the recognition, diagnosis, and timely reporting of chikungunya virus disease cases.
    The American journal of tropical medicine and hygiene 10/2014; 92(1). DOI:10.4269/ajtmh.14-0442 · 2.70 Impact Factor
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    ABSTRACT: Abstract Batai virus (BATV) was identified in mosquitoes in the Caltignaga region of Novarra, northern Italy in 2009. Here, we report the identification of antibodies to BATV in serum samples that were taken from healthy bovines in that region in 2011. BATV has been associated with a mild febrile human illness and identified as the likely parental segment donor in a reassortment event that resulted in the generation of the virulent progeny, Ngari virus. The possible veterinary disease associations of BATV are unknown. The presence of antibodies to BATV in bovine populations confirms local transmission in northern Italy. Given its likely role as a segment donor, an understanding of the geographic and host distributions of BATV is of veterinary and human public health interest.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 09/2014; 14(9). DOI:10.1089/vbz.2014.1596 · 2.30 Impact Factor
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    ABSTRACT: BACKGROUND: Chikungunya virus is a mosquito-borne alphavirus that can cause large outbreaks of acute febrile illness with severe polyarthralgia. It is an emerging health threat to the United States because humans are amplifying hosts and mosquito species that transmit the virus are present in many areas of the country. In late 2013, the first cases of locally-acquired chikungunya virus disease were identified in the Americas. METHODS: We identified laboratory-confirmed chikungunya cases with diagnostic testing performed at the Centers for Disease Control and Prevention, the California Department of Public Health, or Focus Diagnostics from 2010‒2013. We defined a case as a patient with one of the following: 1) chikungunya virus or viral RNA detected by culture or RT-PCR; 2) ≥4-fold rise in anti-chikungunya virus neutralizing antibodies between acute- and convalescent-phase specimens; or 3) anti-chikungunya virus IgM antibodies with either anti-chikungunya virus IgG or neutralizing antibodies. Patients with chikungunya virus or RNA detected in serum were considered viremic. We described the epidemiology of these cases and determined which were reported to ArboNET, the national surveillance system for arboviral disease. RESULTS: From 2010‒2013, 115 laboratory-confirmed chikungunya cases were identified in the United States. Sixty-seven cases were identified in 2010, 10 in 2011, 5 in 2012, and 33 in 2013. The median age of case-patients was 44 years [interquartile range (IQR) 34‒54 years]; only two case-patients were children. Travel history was available for 55 (48%) cases. Of those, 53 (96%) reported travel to Asia and 2 (4%) to Africa. The most commonly reported travel destinations were India (n=37), Indonesia (n=7), and the Philippines (n=7). Six patients were viremic after returning to the United States and an additional 15 patients returned <7 days after illness onset but did not have viral culture or RT-PCR testing performed. Of the 115 cases identified, only 24 (21%) were reported to ArboNET, with a median of 71 days (IQR 51–114 days) between illness onset and reporting. CONCLUSIONS: Since 2010, a median of 22 chikungunya cases were identified per year in the United States. Although viremic travelers pose a theoretical risk for local transmission, no locally-acquired cases were identified. Less than one-quarter of recognized cases were reported to ArboNET; however, chikungunya is not currently a nationally notifiable condition. Given the recent increased risk of introduction into the United States, healthcare providers and public health officials should be educated about the recognition, diagnosis, and timely reporting of chikungunya cases.
    2014 Council of State and Territorial Epidemiologists Annual Conference; 06/2014
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    ABSTRACT: Serodiagnosis of arthropod-borne viruses (arboviruses) at the Division of Vector-Borne Diseases, CDC, employs a combination of individual enzyme-linked immunosorbent assays and microsphere immunoassays (MIAs) to test for IgM and IgG, followed by confirmatory plaque-reduction neutralization tests. Based upon the geographic origin of a sample, it may be tested concurrently for multiple arboviruses, which can be a cumbersome task. The advent of multiplexing represents an opportunity to streamline these types of assays; however, because serologic cross-reactivity of the arboviral antigens often confounds results, it is of interest to employ data analysis methods that address this issue. Here, we constructed 13-virus multiplexed IgM and IgG MIAs that included internal and external controls, based upon the Luminex platform. Results from samples tested using these methods were analyzed using 8 different statistical schemes to identify the best way to classify the data. Geographic batteries were also devised to serve as a more practical diagnostic format, and further samples were tested using the abbreviated multiplexes. Comparative error rates for the classification schemes identified a specific boosting method based on logistic regression "Logitboost" as the classification method of choice. When the data from all samples tested were combined into one set, error rates from the multiplex IgM and IgG MIAs were <5% for all geographic batteries. This work represents both the most comprehensive, validated multiplexing method for arboviruses to date, and also the most systematic attempt to determine the most useful classification method for use with these types of serologic tests.
    PLoS ONE 09/2013; 8(9):e75670. DOI:10.1371/journal.pone.0075670 · 3.23 Impact Factor
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    ABSTRACT: Abstract An outbreak of fever and meningitis/encephalitis occurred in Xinjiang, China, from August 5 to September 3, 2004. In preliminary diagnostic testing, several cerebrospinal fluid (CSF) and serum samples showed positive immunoglobulin M (IgM) antibody to Japanese encephalitis virus. Here, the CSF and serum samples of 6 cases collected at that time were tested by immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), and plaque reduction neutralization assay (PRNT) for the existence of IgM antibody or neutralization antibody against West Nile virus (WNV) or other arboviruses. The results demonstrate the evidence of West Nile infection in Xinjiang, China.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 01/2013; 13(2). DOI:10.1089/vbz.2012.0995 · 2.30 Impact Factor
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    ABSTRACT: Abstract U.S. National Park Service employees may have prolonged exposure to wildlife and arthropods, placing them at increased risk of infection with endemic zoonoses. To evaluate possible zoonotic risks present at both Great Smoky Mountains (GRSM) and Rocky Mountain (ROMO) National Parks, we assessed park employees for baseline seroprevalence to specific zoonotic pathogens, followed by evaluation of incident infections over a 1-year study period. Park personnel showed evidence of prior infection with a variety of zoonotic agents, including California serogroup bunyaviruses (31.9%), Bartonella henselae (26.7%), spotted fever group rickettsiae (22.2%), Toxoplasma gondii (11.1%), Anaplasma phagocytophilum (8.1%), Brucella spp. (8.9%), flaviviruses (2.2%), and Bacillus anthracis (1.5%). Over a 1-year study period, we detected incident infections with leptospirosis (5.7%), B. henselae (5.7%), spotted fever group rickettsiae (1.5%), T. gondii (1.5%), B. anthracis (1.5%), and La Crosse virus (1.5%) in staff members at GRSM, and with spotted fever group rickettsiae (8.5%) and B. henselae (4.3%) in staff at ROMO. The risk of any incident infection was greater for employees who worked as resource managers (OR 7.4; 95% CI 1.4,37.5; p=0.02), and as law enforcement rangers/rescue crew (OR 6.5; 95% CI 1.1,36.5; p=0.03), relative to those who worked primarily in administration or management. The results of this study increase our understanding of the pathogens circulating within both parks, and can be used to inform the development of effective guidelines and interventions to increase visitor and staff awareness and help prevent exposure to zoonotic agents.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 07/2012; 12(11). DOI:10.1089/vbz.2011.0917 · 2.30 Impact Factor
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    ABSTRACT: Eastern equine encephalitis virus (EEEV) is a highly virulent, mosquito-borne alphavirus that causes severe and often fatal neurological disease in humans and horses in eastern North American, the Caribbean, and Mexico and throughout Central and South America. EEEV infection is diagnosed serologically by anti-EEEV-specific IgM detection, with confirmation by the plaque reduction neutralization test (PRNT), which is highly specific for alphaviruses. Live virus is used in the PRNT procedure, which currently requires biosafety level 3 containment facilities and select agent security in the case of EEEV. These requirements restrict the ability of public health laboratories to conduct PRNTs. Sindbis virus (SINV)/EEEV recombinant constructs have been engineered to express the immunogenic structural proteins from 2 wild-type EEEV strains in an attenuated form. These SINV/EEEVs, which are not classified as select agents, were evaluated as alternative diagnostic reagents in a PRNT using human, equine, and murine sera. The results indicate that the chimeric viruses exhibit specificity comparable to that of wild-type EEEV, with only a slight reduction in sensitivity. Considering their benefits in increased safety and reduced regulatory requirements, these chimeric viruses should be highly useful in diagnostic laboratories throughout the Americas.
    Clinical and vaccine Immunology: CVI 07/2011; 18(9):1486-91. DOI:10.1128/CVI.05129-11 · 2.47 Impact Factor
  • JAMA The Journal of the American Medical Association 06/2011; 305(24):2516-2518. · 35.29 Impact Factor
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    ABSTRACT: Chikungunya virus (CHIKV) represents a threat to the United States, because humans amplify CHIKV and vectors that transmit CHIKV are present. We described the epidemiology of laboratory-confirmed chikungunya fever (CHIK) cases in the United States in 1995-2009 and compared states with CHIKV vectors with states with returning viremic CHIK cases. For 2006-2009, we evaluated reporting of CHIK cases to ArboNET, the arboviral surveillance system. In 1995-2009, 109 CHIK cases were identified in the United States; all adult travelers. Sixty-two subjects (57%) had recently visited India, and 13 (12%) had CHIKV viremia. Of the 26 jurisdictions with CHIK cases, 22 (85%) reported the presence of CHIKV vectors. Twelve viremic travelers returned to 6 states with CHIKV vectors. Of the 106 cases identified in 2006-2009, only 27 (25%) were reported to ArboNET, with a median of 122 days (range, 44-273 days) between illness onset and reporting. No locally acquired CHIK cases were identified. However, several viremic travelers returned to states with CHIKV vectors and presented a risk for local transmission. Incomplete and delayed reporting made ArboNET less useful. To minimize the risk of CHIKV spread in the United States, healthcare providers and public health officials should be educated about recognition, diagnosis, and reporting of CHIK cases.
    Clinical Infectious Diseases 03/2011; 52(5):e121-6. DOI:10.1093/cid/ciq214 · 8.89 Impact Factor
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    ABSTRACT: To investigate the infection status and the spatial distribution of Tahyna virus infection among unknown fever cases in Xinjiang, China. Sera samples of unknown fever cases from Kashi in southern Xin-jiang and Yili in northern Xinjiang were tested against Tahyna virus by IFA. Partial positive cases were tested against Tahyna virus/Snowshoe hare virus/Inkoo virus parrelled. Finally, 742 sera samples of unknown fever cases were collected from Kashi, Southern Xinjiang in 2007-2008, the positive rate of IgM antibody against Tahyna virus was 5.3%, the positive rate of IgG antibody against Tahyna virus was 18.3%. 222 sera samples of unknown fever cases were collected from Yili, Northern Xinjiang in 2008, no positive case of IgM antibody against Tahyna was found. 10 cases showed antibody neutralization against Tahyna virus by plaque reduction neutralization test. Our results demonstrate that there is current infection and past infection of Tahyna virus among Southern Xinjiang residents.
    Bing du xue bao = Chinese journal of virology / [bian ji, Bing du xue bao bian ji wei yuan hui] 01/2011; 27(1):71-4.
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    ABSTRACT: Japanese encephalitis virus (JEV) is endemic in Thailand and prevention strategies include vaccination, vector control, and health education. Between July 2003 and August 2005, we conducted hospital-based surveillance for encephalitis at seven hospitals in Bangkok and Hat Yai. Serum and cerebrospinal (CSF) specimens were tested for evidence of recent JEV infection by immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and a plaque reduction neutralization test (PRNT). Of the 147 patients enrolled and tested, 24 (16%) had evidence of acute flavivirus infection: 22 (15%) with JEV and two (1%) with dengue virus. Of the 22 Japanese encephalitis (JE) cases, 10 (46%) were aged ≤ 15 years. The median length of hospital stay was 13 days; one 13-year-old child died. Ten percent of encephalitis patients enrolled in Bangkok hospitals were found to have JEV infection compared to 28% of patients enrolled in hospitals in southern Thailand (p < 0.01). Four (40%) of the 10 children with JE were reported as being vaccinated. JEV remains an important cause of encephalitis among hospitalized patients in Thailand. The high proportion of JE among encephalitis cases is concerning and additional public health prevention efforts or expanded vaccination may be needed.
    International journal of infectious diseases: IJID: official publication of the International Society for Infectious Diseases 10/2010; 14(10):e888-92. DOI:10.1016/j.ijid.2010.03.022 · 1.86 Impact Factor
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    Emerging Infectious Diseases 09/2010; 16(9):1498-500. DOI:10.3201/eid1609.100505 · 6.75 Impact Factor
  • JAMA The Journal of the American Medical Association 06/2010; 303(21):2132-2135. · 35.29 Impact Factor
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    ABSTRACT: From September through early December 2005, an outbreak of yellow fever (YF) occurred in South Kordofan, Sudan, resulting in a mass YF vaccination campaign. In late December 2005, we conducted a serosurvey to assess YF vaccine coverage and to better define the epidemiology of the outbreak in an index village. Of 552 persons enrolled, 95% reported recent YF vaccination, and 25% reported febrile illness during the outbreak period: 13% reported YF-like illness, 4% reported severe YF-like illness, and 12% reported chikungunya-like illness. Of 87 persons who provided blood samples, all had positive YF serologic results, including three who had never been vaccinated. There was also serologic evidence of recent or prior chikungunya virus, dengue virus, West Nile virus, and Sindbis virus infections. These results indicate that YF virus and chikungunya virus contributed to the outbreak. The high prevalence of YF antibody among vaccinees indicates that vaccination was effectively implemented in this remotely located population.
    The American journal of tropical medicine and hygiene 06/2010; 82(6):1146-52. DOI:10.4269/ajtmh.2010.09-0105 · 2.70 Impact Factor
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    ABSTRACT: Serum antibodies from myriad species, particularly birds, can provide key information regarding the transmission and the expansion of the territory of emerging pathogens. Expedient antibody analysis is constrained by a lack of species-specific reagents, a deficiency potentially highlighted by the recent swine-origin influenza A virus (H1N1) outbreak. Available methodologies present difficulties that discourage thorough serologic monitoring of potential disease vectors or hosts. Rapid high-throughput procedures that combined serum amine labeling via biotinylation, contaminant removal, and microsphere-based immunoassays for antibodies to three arboviruses were developed. Agent-specific adaptations of this simple format should facilitate expanded surveillance and diagnostic capabilities regarding pathogens of human and veterinary importance.
    Clinical and vaccine Immunology: CVI 11/2009; 17(1):56-61. DOI:10.1128/CVI.00291-09 · 2.47 Impact Factor
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    ABSTRACT: In 2007, physicians on Yap Island reported an outbreak of illness characterized by rash, conjunctivitis, and arthralgia. Although serum from some patients had IgM antibody against dengue virus, the illness seemed clinically distinct from previously detected dengue. Subsequent testing with the use of consensus primers detected Zika virus RNA in the serum of the patients but no dengue virus or other arboviral RNA. No previous outbreaks and only 14 cases of Zika virus disease have been previously documented. We obtained serum samples from patients and interviewed patients for information on clinical signs and symptoms. Zika virus disease was confirmed by a finding of Zika virus RNA or a specific neutralizing antibody response to Zika virus in the serum. Patients with IgM antibody against Zika virus who had a potentially cross-reactive neutralizing-antibody response were classified as having probable Zika virus disease. We conducted a household survey to estimate the proportion of Yap residents with IgM antibody against Zika virus and to identify possible mosquito vectors of Zika virus. We identified 49 confirmed and 59 probable cases of Zika virus disease. The patients resided in 9 of the 10 municipalities on Yap. Rash, fever, arthralgia, and conjunctivitis were common symptoms. No hospitalizations, hemorrhagic manifestations, or deaths due to Zika virus were reported. We estimated that 73% (95% confidence interval, 68 to 77) of Yap residents 3 years of age or older had been recently infected with Zika virus. Aedes hensilli was the predominant mosquito species identified. This outbreak of Zika virus illness in Micronesia represents transmission of Zika virus outside Africa and Asia. Although most patients had mild illness, clinicians and public health officials should be aware of the risk of further expansion of Zika virus transmission.
    New England Journal of Medicine 07/2009; 360(24):2536-43. DOI:10.1056/NEJMoa0805715 · 55.87 Impact Factor
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    ABSTRACT: The plaque reduction neutralization test (PRNT) is a specific serological test used to identify and confirm arbovirus infection in diagnostic laboratories and monitor immunological protection in vaccine recipients. Wild-type (wt) viruses used in the PRNT may be difficult to grow and plaque titrate, such as the dengue viruses (DENV), and/or may require biosafety level 3 (BSL3) containment, such as West Nile virus (WNV), St. Louis encephalitis virus (SLEV), and Japanese encephalitis virus (JEV). These requirements preclude their use in diagnostic laboratories with only BSL2 capacity. In addition, wt JEV falls under the jurisdiction of the select-agent program and can be used only in approved laboratories. The chimeric vaccine viruses ChimeriVax-WNV and -SLEV have previously been shown to elicit antibody reactivity comparable to that of parental wt WNV and SLEV. ChimeriVax viruses provide advantages for PRNT, as follows: they grow more rapidly than most wt flaviviruses, produce large plaques, require BSL2 conditions, and are not under select-agent restrictions. We evaluated the ChimeriVax-DENV serotype 1 (DENV1), -DENV2, -DENV3, -DENV4, and -JEV for use in PRNT on sera from DENV- and JEV-infected patients and from JEV vaccine recipients. Serostatus agreement was 100% between the ChimeriVax-DENV serotypes and wt prototype DENV and 97% overall with ChimeriVax-JEV compared to prototype Nakayama JEV, 92% in a subgroup of JEV vaccine recipients, and 100% in serum from encephalitis patients naturally infected with JEV. ChimeriVax-DENV and -JEV plaque phenotype and BSL2 requirements, combined with sensitive and specific reactivity, make them good substitutes for wt DENV and JEV in PRNT in public health diagnostic laboratories.
    Clinical and vaccine Immunology: CVI 06/2009; 16(7):1052-9. DOI:10.1128/CVI.00095-09 · 2.47 Impact Factor
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    ABSTRACT: Powassan virus (POWV) disease is a rare human disease caused by a tick-borne encephalitis group flavivirus maintained in a transmission cycle between Ixodes cookei and other ixodid ticks and small and medium-sized mammals. During 1958-1998, only 27 POWV disease cases (mostly Powassan encephalitis) were reported from eastern Canada and the northeastern United States (average, 0.7 cases per year). During 1999-2005, nine cases (described herein) of serologically confirmed POWV disease were reported in the United States (average, 1.3 cases per year): four from Maine, two from New York, and one each from Michigan, Vermont, and Wisconsin. The Michigan and Wisconsin cases are the first ever reported from the north-central United States. Of these nine patients, 5 (56%) were men, the median age was 69 years (range: 25-91 years), and 6 (67%) had onset during May-July. All but one patient developed encephalitis with acute onset of profound muscle weakness, confusion, and other severe neurologic signs. In one case, no neurologic symptoms were present but the presence of pleocytosis, an elevated cerebrospinal fluid (CSF) protein concentration, and POWV-specific immunoglobulin M in CSF suggested neuroinvasion. All patients recovered from their acute disease, but most had long-term neurologic sequelae. Periresidential ecologic investigations were performed in three cases, including tests of local mammals and ticks for evidence of POWV infection. Woodchucks (Marmota monax), striped skunks (Mephitis mephitis), and a raccoon (Procyon lotor) collected at two of the Maine case-patients' residences had neutralizing antibody titers to POWV. I. cookei were found on woodchucks and skunks and questing in grassy areas of one of these residences; all were negative for POWV. Although POWV disease is rare, it is probably under-recognized, and it causes significant morbidity, and thus is an additional tick-borne emerging infectious disease entity. Because no vaccine or specific therapy is available, the basis of prevention is personal protection from ticks (or "tick hygiene") and reduced exposure to peridomestic wild mammals.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 11/2008; 8(6):733-40. DOI:10.1089/vbz.2008.0022 · 2.30 Impact Factor

Publication Stats

448 Citations
200.09 Total Impact Points


  • 2007–2015
    • Centers for Disease Control and Prevention
      • Division of Vector-Borne Diseases
      Атланта, Michigan, United States
    • Arizona Department of Health Services
      Phoenix, Arizona, United States
  • 2011
    • University of Texas Medical Branch at Galveston
      • Department of Pathology
      Galveston, Texas, United States
  • 2005
    • National Institute of Allergy and Infectious Diseases
      Maryland, United States