Life Sciences Commons^™

Molecular Evolution Of Dengue Type 2 Virus In Thailand, Rebeca Rico-Hesse, Lisa M. Harrison, Ananda Nisalak, David W. Vaughn, Siripen Kalayanarooj, Sharone Green, Alan L. Rothman, Francis A. Ennis

Sharone Green

Dengue is a mosquito-borne viral infection that in recent years has become a major international public health concern. Dengue hemorrhagic fever (DHF), first recognized in Southeast Asia in the 1950s, is today a leading cause of childhood death in many countries. The pathogenesis of this illness is poorly understood, mainly because there are no laboratory or animal models of disease. We have studied the genetic relationships of dengue viruses of serotype 2, one of four antigenically distinct dengue virus groups, to determine if viruses obtained from cases of less severe dengue fever (DF) have distinct evolutionary origins from those obtained …

Rapid Diagnosis Of Dengue Viremia By Reverse Transcriptase-Polymerase Chain Reaction Using 3'-Noncoding Region Universal Primers, T. Mirawati Sudiro, Hiroaki Ishiko, Sharone Green, Ananda Nisalak, David W. Vaughn, Siripen Kalayanarooj, Alan L. Rothman, Boonyos Raengsakulrach, Jurand Janus, Ichiro Kurane, Francis A. Ennis

Sharone Green

A reverse transcriptase-polymerase chain reaction (RT-PCR) method was developed as a rapid diagnostic test of dengue viremia. To detect dengue viruses in serum or plasma specimens, a pair of universal primers was designed for use in the RT-PCR. Using these primers, the 3'-noncoding region of dengue virus types 1, 2, 3, and 4 could be amplified, but not those of other flaviviruses, such as West Nile virus, Japanese encephalitis virus, and yellow fever virus, or the alphavirus Sindbis virus. The sensitivity of the RT-PCR assay was similar to that of a quantitative fluorescent focus assay of dengue viruses in cell …

Evaluation Of Cardiac Involvement In Children With Dengue By Serial Echocardiographic Studies, Tawatchai Kirawittaya, In-Kyu Yoon, Sineewanlaya Wichit, Sharone Green, Francis A. Ennis, Robert V. Gibbons, Stephen J. Thomas, Alan L. Rothman, Siripen Kalayanarooj, Anon Srikiatkhachorn

Sharone Green

BACKGROUND: Infection with dengue virus results in a wide range of clinical manifestations from dengue fever (DF), a self-limited febrile illness, to dengue hemorrhagic fever (DHF) which is characterized by plasma leakage and bleeding tendency. Although cardiac involvement has been reported in dengue, the incidence and the extent of cardiac involvement are not well defined. METHODS AND PRINCIPAL FINDINGS: We characterized the incidence and changes in cardiac function in a prospective in-patient cohort of suspected dengue cases by serial echocardiography. Plasma leakage was detected by serial chest and abdominal ultrasonography. Daily cardiac troponin-T levels were measured. One hundred and eighty …

The Spatial Dynamics Of Dengue Virus In Kamphaeng Phet, Thailand, Piraya Bhoomiboonchoo, Robert V. Gibbons, Angkana Huang, In-Kyu Yoon, Darunee Buddhari, Ananda Nisalak, Natkamol Chansatiporn, Mathuros Thipayamongkolgul, Siripen Kalanarooj, Timothy Endy, Alan L. Rothman, Anon Srikiatkhachorn, Sharone Green, Mammen P. Mammen, Derek A. Cummings, Henrik Salje

Sharone Green

BACKGROUND: Dengue is endemic to the rural province of Kamphaeng Phet, Northern Thailand. A decade of prospective cohort studies has provided important insights into the dengue viruses and their generated disease. However, as elsewhere, spatial dynamics of the pathogen remain poorly understood. In particular, the spatial scale of transmission and the scale of clustering are poorly characterized. This information is critical for effective deployment of spatially targeted interventions and for understanding the mechanisms that drive the dispersal of the virus.

METHODOLOGY/PRINCIPAL FINDINGS: We geocoded the home locations of 4,768 confirmed dengue cases admitted to the main hospital in Kamphaeng Phet …

Preliminary Evaluation Of Near Infrared Spectroscopy As A Method To Detect Plasma Leakage In Children With Dengue Hemorrhagic Fever, Babs R. Soller, Anon Srikiatkhachorn, Fengmei Zou, Alan L. Rothman, In-Kyu Yoon, Robert V. Gibbons, Siripen Kalayanarooj, Stephen J. Thomas, Sharone Green

Sharone Green

BACKGROUND: Dengue viral infections are prevalent in the tropical and sub-tropical regions of the world, resulting in substantial morbidity and mortality. Clinical manifestations range from a self-limited fever to a potential life-threatening plasma leakage syndrome (dengue hemorrhagic fever). The objective of this study was to assess the utility of near infrared spectroscopy (NIRS) measurements of muscle oxygen saturation (SmO2) as a possible continuous measure to detect plasma leakage in children with dengue.

METHODS: Children ages 6 months to 15 years of age admitted with suspected dengue were enrolled from the dengue ward at Queen Sirikit National Institute for Child Health. …

Sequential Dengue Virus Infections Detected In Active And Passive Surveillance Programs In Thailand, 1994-2010, Piraya Bhoomiboonchoo, Ananda Nisalak, Natkamol Chansatiporn, In-Kyu Yoon, Siripen Kalayanarooj, Mathuros Thipayamongkolgul, Timothy Endy, Alan L. Rothman, Sharone Green, Anon Srikiatkhachorn, Darunee Buddhari, Mammen P. Mammen, Robert V. Gibbons

Sharone Green

BACKGROUND: The effect of prior dengue virus (DENV) exposure on subsequent heterologous infection can be beneficial or detrimental depending on many factors including timing of infection. We sought to evaluate this effect by examining a large database of DENV infections captured by both active and passive surveillance encompassing a wide clinical spectrum of disease.

METHODS: We evaluated datasets from 17 years of hospital-based passive surveillance and nine years of cohort studies, including clinical and subclinical DENV infections, to assess the outcomes of sequential heterologous infections. Chi square or Fisher's exact test was used to compare proportions of infection outcomes such …

A Comparative Study Of Leptospirosis And Dengue In Thai Children, Daniel H. Libraty, Khin S. A. Myint, Clinton K. Murray, Robert V. Gibbons, Mammen P. Mammen, Timothy P. Endy, Wenjun Li, David W. Vaughn, Ananda Nisalak, Siripen Kalayanarooj, Duane R. Hospenthal, Sharone Green, Alan L. Rothman, Francis A. Ennis

Sharone Green

BACKGROUND: Leptospirosis is an emerging zoonosis that is often under-recognized in children and commonly confused with dengue in tropical settings. An enhanced ability to distinguish leptospirosis from dengue in children would guide clinicians and public health personnel in the appropriate use of limited healthcare resources. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a prospective, hospital-based, study of children with acute febrile illnesses and dengue in Thailand. Among the children without dengue, we identified those with leptospirosis using anti-leptospira IgM and microscopic agglutination titers in paired acute and convalescent blood samples. We then performed a case-control comparison of symptoms, signs, and clinical laboratory values …

Determinants Of Inapparent And Symptomatic Dengue Infection In A Prospective Study Of Primary School Children In Kamphaeng Phet, Thailand, Timothy P. Endy, Kathryn B. Anderson, Ananda Nisalak, In-Kyu Yoon, Sharone Green, Alan L. Rothman, Stephen J. Thomas, Richard G. Jarman, Daniel H. Libraty, Robert V. Gibbons

Sharone Green

BACKGROUND: Dengue viruses are a major cause of morbidity in tropical and subtropical regions of the world. Inapparent dengue is an important component of the overall burden of dengue infection. It provides a source of infection for mosquito transmission during the course of an epidemic, yet by definition is undetected by health care providers. Previous studies of inapparent or subclinical infection have reported varying ratios of symptomatic to inapparent dengue infection. METHODOLOGY/PRINCIPAL FINDINGS: In a prospective study of school children in Northern Thailand, we describe the spatial and temporal variation of the symptomatic to inapparent (S:I) dengue illness ratio. Our …

T Cell Receptor Vbeta Gene Usage In Thai Children With Dengue Virus Infection, Susan J. Gagnon, Anita M. Leporati, Sharone Green, Siripen Kalayanarooj, David W. Vaughn, Henry A. F. Stephens, Saroj Suntayakorn, Ichiro Kurane, Francis A. Ennis, Alan L. Rothman

Sharone Green

T lymphocyte activation during dengue is thought to contribute to the pathogenesis of dengue hemorrhagic fever (DHF). We examined the T cell receptor Vbeta gene usage by a reverse transcriptase-polymerase chain reaction assay during infection and after recovery in 13 children with DHF and 13 children with dengue fever (DF). There was no deletion of specific Vbeta gene families. We detected significant expansions in usage of single Vbeta families in six subjects with DHF and three subjects with DF over the course of infection, but these did not show an association with clinical diagnosis, viral serotype, or HLA alleles. Differences …

T-Cell Responses To Dengue Virus In Humans, Ichiro Kurane, Takaji Matsutani, Ryuji Suzuki, Tomohiko Takasaki, Siripen Kalayanarooj, Sharone Green, Alan L. Rothman, Francis A. Ennis

Sharone Green

Dengue virus (DENV) is a leading cause of morbidity and mortality in most tropical and subtropical areas of the world. Dengue virus infection induces specific CD4+CD8- and CD8+CD4- T cells in humans. In primary infection, T-cell responses to DENV are serotype cross-reactive, but the highest response is to the serotype that caused the infection. The epitopes recognized by DENV-specific T cells are located in most of the structural and non-structural proteins, but NS3 is the protein that is most dominantly recognized. In patients with dengue hemorrhagic fever (DHF) caused by secondary DENV infection, T cells are highly activated in vivo. …

Prediction Of Dengue Disease Severity Among Pediatric Thai Patients Using Early Clinical Laboratory Indicators, James A. Potts, Robert V. Gibbons, Alan L. Rothman, Anon Srikiatkhachorn, Stephen J. Thomas, Pra-On Supradish, Stephenie C. Lemon, Daniel H. Libraty, Sharone Green, Siripen Kalayanarooj

Sharone Green

BACKGROUND: Dengue virus is endemic in tropical and sub-tropical resource-poor countries. Dengue illness can range from a nonspecific febrile illness to a severe disease, Dengue Shock Syndrome (DSS), in which patients develop circulatory failure. Earlier diagnosis of severe dengue illnesses would have a substantial impact on the allocation of health resources in endemic countries. METHODS AND FINDINGS: We compared clinical laboratory findings collected within 72 hours of fever onset from a prospective cohort children presenting to one of two hospitals (one urban and one rural) in Thailand. Classification and regression tree analysis was used to develop diagnostic algorithms using different …

Robust Intrapulmonary Cd8 T Cell Responses And Protection With An Attenuated N1l Deleted Vaccinia Virus, Anuja Mathew, Joel O'Bryan, William L. Marshall, Girish J. Kotwal, Masanori Terajima, Sharone Green, Alan L. Rothman, Francis A. Ennis

Sharone Green

BACKGROUND: Vaccinia viruses have been used as a model for viral disease and as a protective live vaccine. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the immunogenicity of an attenuated strain of vaccinia virus engineered to inactivate the N1L gene (vGK5). Using the intranasal route, this recombinant virus was 2 logs less virulent compared to the wildtype VACV-WR. Infection by the intranasal, intraperitoneal, and tail scarification routes resulted in the robust induction of cytolytic virus-specific CD8 T cells in the spleens and the lungs. VACV-specific antibodies were also detected in the sera of mice infected 3-5 months prior with the attenuated …

Virus-Induced Decline In Soluble Vascular Endothelial Growth Receptor 2 Is Associated With Plasma Leakage In Dengue Hemorrhagic Fever, Anon Srikiatkhachorn, Chuanpis Ajariyakhajorn, Timothy P. Endy, Siripen Kalayanarooj, Daniel H. Libraty, Sharone Green, Francis A. Ennis, Alan L. Rothman

Sharone Green

Some individuals infected with dengue virus develop dengue hemorrhagic fever (DHF), a viral hemorrhagic disease characterized by a transient period of localized plasma leakage. To determine the importance of vascular endothelial growth factor A (VEGF-A) in this syndrome, we compared plasma levels of VEGF-A and the soluble forms of its receptors in patients with DHF to patients with dengue fever (DF), a milder form of dengue virus infection without plasma leakage. We observed a rise in the plasma levels of free, but not total VEGF-A in DHF patients at the time of plasma leakage. This was associated with a decline …

Cross-Reactivity And Expansion Of Dengue-Specific T Cells During Acute Primary And Secondary Infections In Humans, Heather L. Friberg-Robertson, Hema Sundara Bashyam, Tomoko Toyosaki-Maeda, James A. Potts, Thomas C. Greenough, Siripen Kalayanarooj, Robert V. Gibbons, Ananda Nisalak, Anon Srikiatkhachorn, Sharone Green, Henry A. F. Stephens, Alan L. Rothman, Anuja Mathew

Sharone Green

Serotype-cross-reactive memory T cells responding to secondary dengue virus (DENV) infection are thought to contribute to disease. However, epitope-specific T cell responses have not been thoroughly compared between subjects with primary versus secondary DENV infection. We studied CD8(+) T cells specific for the HLA-A*1101-restricted NS3(133) epitope in a cohort of A11(+) DENV-infected patients throughout acute illness and convalescence. We compared the expansion, serotype-cross-reactivity, and activation of these cells in PBMC from patients experiencing primary or secondary infection and mild or severe disease by flow cytometry. Our results show expansion and activation of DENV-specific CD8(+) T cells during acute infection, which …