Publications (21)101.8 Total impact
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Article: Persistence of vaccinia at the site of smallpox vaccination.
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ABSTRACT: Persistence of vaccinia at vaccination sites may help determine the risk associated with secondary transmission. Culture, PCR, and antigen detection were performed on serial vaccination site swab specimens. On day 21 after vaccination, 37% of volunteers were culture positive, most of whom had received vaccine for the first time. Vaccinia is detectable at least through day 21 after vaccination.Clinical Infectious Diseases 02/2008; 46(1):101-2. · 9.15 Impact Factor -
Article: Direct broad-range detection of alphaviruses in mosquito extracts.
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ABSTRACT: Members of the genus Alphavirus are a diverse group of principally mosquito-borne RNA viruses. There are at least 29 species and many more subtypes of alphaviruses and some are considered potential bioweapons. We have developed a multi-locus RT-PCR followed by electrospray ionization mass spectrometry (RT-PCR/ESI-MS) assay that uses the amplicon base compositions to detect and identify alphaviruses. A small set of primer pairs targeting conserved sites in the alphavirus RNA genome were used to amplify a panel of 36 virus isolates representing characterized Old World and New World alphaviruses. Base compositions from the resulting amplicons could be used to unambiguously determine the species or subtype of 35 of the 36 isolates. The assay detected, without culture, Venezuelan equine encephalitis virus (VEEV), Eastern equine encephalitis virus (EEEV), and mixtures of both in pools consisting of laboratory-infected and -uninfected mosquitoes. Further, the assay was used to detect alphaviruses in naturally occurring mosquito vectors collected from locations in South America and Asia. Mosquito pools collected near Iquitos, Peru, were found to contain an alphavirus with a very distinct signature. Subsequent sequence analysis confirmed that the virus was a member of the Mucambo virus species (subtype IIID in the VEEV complex). The assay we have developed provides a rapid, accurate, and high-throughput assay for surveillance of alphaviruses.Virology 12/2007; 368(2):286-95. · 3.35 Impact Factor -
Article: Vaccinia DNA in blood after smallpox vaccination.
JAMA The Journal of the American Medical Association 10/2006; 296(11):1350-1; author reply 1351-2. · 30.03 Impact Factor -
Article: Testosterone correlates with Venezuelan equine encephalitis virus infection in macaques.
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ABSTRACT: Here we briefly report testosterone and cytokine responses to Venezuelan equine encephalitis virus (VEEV) in macaques which were used as part of a larger study conducted by the Department of Defense to better characterize pathological responses to aerosolized VEEV in non-human primates. Serial samples were collected and analyzed for testosterone and cytokines prior to and during infection in 8 captive male macaques. Infected animals exhibited a febrile response with few significant changes in cytokine levels. Baseline testosterone levels were positively associated with viremia following exposure and were significantly higher than levels obtained during infection. Such findings suggest that disease-induced androgen suppression is a reasonable area for future study. Decreased androgen levels during physiological perturbations may function, in part, to prevent immunosuppression by high testosterone levels and to prevent the use of energetic resources for metabolically-expensive anabolic functions.Virology Journal 02/2006; 3:19. · 2.34 Impact Factor -
Article: Absence of oropharyngeal vaccinia virus after vaccinia (smallpox) vaccination.
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ABSTRACT: With the resumption of the vaccinia (smallpox) vaccination, questions regarding transmission risk prompted this study to determine whether vaccinia virus could be detected in the oropharynx of adults recently vaccinated with vaccinia (smallpox) vaccine. German, Russian, and American studies on the oropharyngeal presence of vaccinia virus revealed conflicting results in different age groups. To measure vaccinia viral particle or antigen presence in the oropharynx of adult health care workers after vaccination with vaccinia (smallpox) vaccine using viral culture and high-sensitivity assays (polymerase chain reaction [PCR] and electrochemiluminescence) and to determine whether there is an association between the presence of vaccinia virus and adverse reactions. A total of 155 adults (primary vaccinees and revaccinees) were enrolled for 1 baseline and 5 subsequent throat swabs. The swabs were evaluated using viral culture, PCR, and electrochemiluminescence. Of the 155 participants, 144 had more than 2 throat swabs in the 2 weeks after vaccination. Of the 801 specimens evaluated, there were no positive results by culture, PCR, or electrochemiluminescence except in the control samples (n = 6), which were positive by all 3 methods. Based on the absence of detectable vaccinia virus in this study population, one can be 95% certain that the true rate of vaccinia virus in the oropharynx of adults during the 2 weeks after vaccination with vaccinia (smallpox) vaccine is 0% to 3.3%. These data should be reassuring to the medical community and support the Advisory Committee on Immunization Practice guidelines that respiratory precautions are not necessary after vaccinia (smallpox) vaccination in healthy adults.Annals of allergy, asthma & immunology: official publication of the American College of Allergy, Asthma, & Immunology 07/2005; 94(6):682-5. · 2.83 Impact Factor -
Article: Venezuelan equine encephalitis virus, southern Mexico.
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ABSTRACT: Equine epizootics of Venezuelan equine encephalitis (VEE) occurred in the southern Mexican states of Chiapas in 1993 and Oaxaca in 1996. To assess the impact of continuing circulation of VEE virus (VEEV) on human and animal populations, serologic and viral isolation studies were conducted in 2000 to 2001 in Chiapas State. Human serosurveys and risk analyses indicated that long-term endemic transmission of VEEV occurred among villages with seroprevalence levels of 18% to 75% and that medical personnel had a high risk for VEEV exposure. Seroprevalence in wild animals suggested cotton rats as possible reservoir hosts in the region. Virus isolations from sentinel animals and genetic characterizations of these strains indicated continuing circulation of a subtype IE genotype, which was isolated from equines during the recent VEE outbreaks. These data indicate long-term enzootic and endemic VEEV circulation in the region and continued risk for disease in equines and humans.Emerging infectious diseases 01/2005; 10(12):2113-21. · 6.17 Impact Factor -
Chapter: Concepts for the Development of Immunodiagnostic Assays for Detection and Diagnosis of Biothreat Agents
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ABSTRACT: An integrated approach to agent detection and identification provides the most reliable laboratory data and is essential to a complete and accurate disease diagnosis. To achieve more rapid biological agent identification with a high level of confidence, a combination of state-of-the-art antigen and nucleic acid analysis methods is required. The most significant problem associated with the development of an integrated diagnostic system has been the inability of antigen-detection technologies to detect agents with sensitivities approaching those of nucleic acid-detection technologies. These differences in assay sensitivity increase the probability of obtaining disparate results, thus complicating medical decisions. However, advances in immunodiagnostic technologies provide the basis for developing antigen-detection platforms capable of meeting stringent requirements for sensitivity, specificity, assay speed, robustness, and simplicity. Such advances must be exploited to increase the confidence of immunodiagnostic testing and to ensure the success of the integrated approach toward diagnosis of disease caused by biological warfare (BW) agents.12/2004: pages 551-579; -
Article: Encephalitis and Sandfly Fever (Sicilian) Virus Infection: Case Report and Review of the Literature
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ABSTRACT: A 30-year-old man developed severe encephalitis with status epilepticus following 2 days of an acute gastroenteritislike illness while in Iraq. Tests for usual arboviral and enteroviral pathogens were negative, but the sandfly fever virus (Sicilian type) immunoglobulin M was positive. Neurologic deficits persist 3 months after the onset of his illness. To our knowledge, this is the first report of sandfly fever virus (Sicilian type)-associated encephalitis. When tests for more common pathogens are negative, providers taking care of soldiers or travelers returning from endemic areas should consider sandfly fever in the differential diagnosis of unexplained encephalitis.Infectious Disease in Clinical Practice 10/2004; 12(6):352-354. -
Article: Monkeypox virus detection in rodents using real-time 3'-minor groove binder TaqMan assays on the Roche LightCycler.
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ABSTRACT: During the summer of 2003, an outbreak of human monkeypox occurred in the Midwest region of the United States. In all, 52 rodents suspected of being infected with monkeypox virus were collected from an exotic pet dealer and from private homes. The rodents were euthanized and submitted for testing to the United States Army Medical Research Institute of Infectious Diseases by the Galesburg Animal Disease Laboratory, Illinois Department of Agriculture. The rodent tissue samples were appropriately processed and then tested by using an integrated approach involving real-time polymerase chain reaction (PCR) assays, an antigen-detection immunoassay, and virus culture. We designed and extensively tested two specific real-time PCR assays for rapidly detecting monkeypox virus DNA using the Vaccinia virus F3L and N3R genes as targets. The assays were validated against panels of orthopox viral and miscellaneous bacterial DNAs. A pan-orthopox electrochemiluminescence (ECL) assay was used to further confirm the presence of Orthopoxvirus infection of the rodents. Seven of 12 (58%) animals (seven of 52 (15%) of all animals) tested positive in both monkeypox-specific PCR assays and two additional pan-orthopox PCR assays (in at least one tissue). The ECL results showed varying degrees of agreement with PCR. One hamster and three gerbils were positive by both PCR and ECL for all tissues tested. In addition, we attempted to verify the presence of monkeypox virus by culture on multiple cell lines, by immunohistology, and by electron microscopy, with negative results. Sequencing the PCR products from the samples indicated 100% identity with monkeypox virus strain Zaire-96-I-16 (a human isolate from the Congo). These real-time PCR and ECL assays represent a significant addition to the battery of tests for the detection of various orthopoxviruses. In light of the recent monkeypox virus transmissions, early detection of the virus is crucial for both natural outbreaks and potential acts of bioterrorism.Laboratory Investigation 10/2004; 84(9):1200-8. · 3.64 Impact Factor -
Article: Development and evaluation of an efficient 3'-noncoding region based SARS coronavirus (SARS-CoV) RT-PCR assay for detection of SARS-CoV infections.
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ABSTRACT: The severe acute respiratory syndrome (SARS) epidemic originating from China in 2002 was caused by a previously uncharacterized coronavirus that could be identified by specific RT-PCR amplification. Efforts to control future SARS outbreaks depend on the accurate and early identification of SARS-CoV infected patients. A real-time fluorogenic RT-PCR assay based on the 3'-noncoding region (3'-NCR) of SARS-CoV genome was developed as a quantitative SARS diagnostic tool. The ideal amplification efficiency of a sensitive SARS-CoV RT-PCR assay should yield an E value (PCR product concentration increase per amplification cycle) equal to 2.0. It was demonstrated that the 3'-NCR SARS-CoV based RT-PCR reactions could be formulated to reach excellent E values of 1.81, or 91% amplification efficacy. The SARS-CoV cDNA preparations derived from viral RNA extract and the cloned recombinant plasmid both exhibit the identical amplification characteristics, i.e. amplification efficacy using the same PCR formulation developed in this study. The viral genomic copy (or genomic equivalences, GE) per infectious unit (GE/pfu) of SARS-CoV used in this study was also established to be approximate 1200-1600:1. The assay's detection sensitivity could reach 0.005 pfu or 6-8 GE per assay. It was preliminarily demonstrated that the assay could efficiently detect SARS-CoV from clinical specimens of SARS probable and suspected patients identified in Taiwan. The 3'-NCR based SARS-CoV assay demonstrated 100% diagnostic specificity testing samples of patients with acute respiratory disease from a non-SARS epidemic region.Journal of Virological Methods 10/2004; 120(1):33-40. · 2.01 Impact Factor -
Article: Department of Defense West Nile virus surveillance in 2002.
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ABSTRACT: The Department of Defense (DoD) has engaged in West Nile virus (WNV) surveillance and response since 1999. In 2002, the three Services continued their cooperative, multidisciplinary approach to the WNV outbreak. Activities included a doubling of mosquito surveillance and vector control responses, extension of and doubling of bird and nonhuman mammal surveillance to all four continental United States regions, expanded diagnostic testing by DoD laboratories, and installation environmental clean up and personnel protection campaigns. Medical treatment facilities conducted passive surveillance and reported possible cases in DoD health care beneficiaries. Efforts were coordinated through active communication within installations, with commands, and with surrounding communities. Undertaken activities complemented each other to maximize surveillance coverage. The surveillance detected WNV on 44 DoD installations. It led directly to vector control and prevention activities, and there were no confirmed cases of WNV reported in the DoD force. This multi-Service effort is a surveillance template for future outbreaks that threaten DoD force health.Military medicine 07/2004; 169(6):421-8. · 0.92 Impact Factor -
Article: Use of a recombinant envelope protein subunit antigen for specific serological diagnosis of West Nile virus infection.
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ABSTRACT: Serological diagnosis of West Nile virus (WNV) infection is complicated by extensive antigenic cross-reactivity with other closely related flaviviruses, such as St. Louis encephalitis virus. Here we describe a recombinant, bacterially expressed antigen equivalent to structural domain III of the WNV envelope protein that has allowed clear discrimination of antibody responses to WNV from those against other related flaviviruses in indirect enzyme-linked immunosorbent assays using standardized control antisera and field-collected samples.Journal of Clinical Microbiology 07/2004; 42(6):2759-65. · 4.15 Impact Factor -
Article: Evidence for arbovirus dissemination conduits from the mosquito (Diptera: Culicidae) midgut.
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ABSTRACT: The mechanism by which arboviruses bypass the basal lamina of mosquito midgut cells and enter the body cavity has been unclear. Experiments using Venezuelan equine encephalitis viral replicon particles, which express the green fluorescent protein gene in cells, indicate the operation of tissue conduits, possibly involving tracheae and visceral muscles, that facilitate virus movement through the basal lamina. Ultrastructural studies of the midgut reveal evidence for possible complete penetration of the basal lamina by tracheal cells and regions of modified basal lamina associated with visceral muscle. The modified basal lamina closely resembles proventricular matrix material known to allow virus passage.Journal of Medical Entomology 06/2004; 41(3):467-75. · 1.76 Impact Factor -
Article: Endemic Venezuelan equine encephalitis in northern Peru.
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ABSTRACT: Since Venezuelan equine encephalitis virus (VEEV) was isolated in Peru in 1942, >70 isolates have been obtained from mosquitoes, humans, and sylvatic mammals primarily in the Amazon region. To investigate genetic relationships among the Peru VEEV isolates and between the Peru isolates and other VEEV strains, a fragment of the PE2 gene was amplified and analyzed by single-stranded conformation polymorphism. Representatives of seven genotypes underwent sequencing and phylogenetic analysis. The results identified four VEE complex lineages that cocirculate in the Amazon region: subtypes ID (Panama and Colombia/Venezuela genotypes), IIIC, and a new, proposed subtype IIID, which was isolated from a febrile human, mosquitoes, and spiny rats. Both ID lineages and the IIID subtype are associated with febrile human illness. Most of the subtype ID isolates belonged to the Panama genotype, but the Colombia/Venezuela genotype, which is phylogenetically related to epizootic strains, also continues to circulate in the Amazon basin.Emerging infectious diseases 05/2004; 10(5):880-8. · 6.17 Impact Factor -
Article: Lack of vaccinia viremia after smallpox vaccination.
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ABSTRACT: Although the transmission of certain viral infections (human immunodeficiency virus, hepatitis B and C viruses, and West Nile virus) through donated blood products is well described, the risk of transmitting vaccinia virus after smallpox vaccination is unknown. Blood samples from patients receiving the smallpox vaccine were obtained before vaccination; then from one-half of the study group on alternate days for each of the first 10 days after vaccination; then from all patients on days 14 and 21 after vaccination. Samples were analyzed by culture, polymerase chain reaction, and antigen detection (electrochemiluminescence) assay for the presence of vaccinia virus. Two hundred and twenty samples from 28 volunteers were processed by all 3 laboratory detection methods and all were negative for the presence of vaccinia virus (confidence interval, 0%-12.3%). Viremia with vaccinia virus after smallpox vaccination appears to be an uncommon occurrence.Clinical Infectious Diseases 03/2004; 38(3):456-8. · 9.15 Impact Factor -
Article: West Nile virus in Mexico: evidence of widespread circulation since July 2002.
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ABSTRACT: West Nile virus (WNV) antibodies were detected in horses from five Mexican states, and WNV was isolated from a Common Raven in the state of Tabasco. Phylogenetic studies indicate that this isolate, the first from Mexico, is related to strains from the central United States but has a relatively high degree of sequence divergence.Emerging infectious diseases 01/2004; 9(12):1604-7. · 6.17 Impact Factor -
Article: DNA vaccine for West Nile virus infection in fish crows (Corvus ossifragus).
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ABSTRACT: A DNA vaccine for West Nile virus (WNV) was evaluated to determine whether its use could protect fish crows (Corvus ossifragus) from fatal WNV infection. Captured adult crows were given 0.5 mg of the DNA vaccine either orally or by intramuscular (IM) inoculation; control crows were inoculated or orally exposed to a placebo. After 6 weeks, crows were challenged subcutaneously with 105 plaque-forming units of WNV (New York 1999 strain). None of the placebo inoculated-placebo challenged birds died. While none of the 9 IM vaccine-inoculated birds died, 5 of 10 placebo-inoculated and 4 of 8 orally vaccinated birds died within 15 days after challenge. Peak viremia titers in birds with fatal WNV infection were substantially higher than those in birds that survived infection. Although oral administration of a single DNA vaccine dose failed to elicit an immune response or protect crows from WNV infection, IM administration of a single dose prevented death and was associated with reduced viremia.Emerging infectious diseases 10/2003; 9(9):1077-81. · 6.17 Impact Factor -
Article: Detection of West Nile virus-infected mosquitoes and seropositive juvenile birds in the vicinity of virus-positive dead birds.
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ABSTRACT: Mosquitoes and wild birds were collected from three sites near locations in the New York City metropolitan area where single, West Nile (WN) virus-positive dead birds were found early in the 2000 transmission season. The mosquitoes were tested for the presence of infectious virus with a Vero cell culture assay and for WN viral RNA by using reverse transcriptase-polymerase chain reaction (RT-PCR) protocols. Serum samples from wild birds were tested for the presence of neutralizing antibodies against WN virus. Infectious WN virus and WN viral RNA were found in Culex species adult mosquitoes from each of the three sites, and a seropositive hatch-year house sparrow (Passer domesticus) was found in one of the three sites. Molecular techniques used to identify the species in the positive mosquito pools found that most of the pools contained a combination of Culex pipiens and Cx. restuans. The minimum infection rate in Culex species mosquitoes from the sites ranged from 0.2 to 6.0 per 1,000 specimens tested. The results demonstrated that, at least early in the transmission season, detection of a WN virus-positive dead bird indicates a local WN virus transmission cycle. This information is valuable in focusing subsequent surveillance and vector management programs. In addition, the RT-PCR procedure for detecting WN viral RNA in mosquito pools detected more positive pools than did the Vero cell plaque assay.The American journal of tropical medicine and hygiene 12/2002; 67(5):492-6. · 2.59 Impact Factor -
Article: Short report: Isolation and identification of Venezuelan equine encephalitis virus from a human in Panama.
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ABSTRACT: Venezuelan equine encephalitis (VEE) virus was isolated from a febrile human in Panama. The patient became febrile approximately 10 days after returning from Gatun Lake in Panama. The virus was isolated from the acute phase serum and identified as VEE, subtype ID virus by monoclonal antibodies, and was confirmed by cross plaque-reduction neutralization tests.The American journal of tropical medicine and hygiene 08/2002; 67(1):112-3. · 2.59 Impact Factor -
Article: An outbreak of West Nile virus in a New York City captive wildlife population.
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ABSTRACT: An outbreak of West Nile virus (WNV) in and around New York City during the late summer of 1999 was the cause of extensive mortality among free-ranging birds. Within the Bronx Zoo/Wildlife Conservation Park, viral activity was also observed and produced some morbidity and mortality among specimens in the zoo's bird collection and probably caused morbidity in at least one specimen from the zoo's mammal collection. To determine the extent of the outbreak and attempt to ascertain the temporal appearance of virus within the park, a serologic survey of birds and mammals was performed. The survey showed that 34% of tested birds (125 of 368; 124 species) were positive for antibody to WNV. The virus caused a disease to infection ratio of 22% (27 of 125) among birds with a 70% (19 of 27) case fatality rate. In contrast, only 8% of the mammals (9 of 117; 35 species) possessed antibody to WNV and there was no virus-associated mortality. Testing of banked and fresh sera obtained from both birds and mammals revealed that there was no evidence of WNV circulation before the 1999 outbreak and that birds introduced into the park were not the source of the New York outbreak. West Nile virus RNA was detected in tissues from one bird that died in February 2000, long after the end of the mosquito transmission season. The potential importance of zoologic parks as possible sentinels for emerging diseases is discussed.The American journal of tropical medicine and hygiene 08/2002; 67(1):67-75. · 2.59 Impact Factor
Top co-authors
Top Journals
Institutions
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2004–2008
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Walter Reed National Military Medical Center
- Department of Infectious Diseases
Washington, D. C., DC, USA -
U.S. Army Medical Research Institute of Infectious Diseases
Frederick, MD, USA -
Ohio University
- Department of Biomedical Sciences
Athens, OH, USA
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2006
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University of Wisconsin - Milwaukee
- Department of Anthropology
Milwaukee, WI, USA
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2005
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University of Texas Medical Branch at Galveston
Galveston, TX, USA
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2002
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United States Army Medical Research Institute for Infectious Diseases
Frederick, MD, USA
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