LCDR Tadeusz J. Kochel, Ph.D., Director Virology Program, NMRCD-Peru
Dengue is one of the most important emerging tropical diseases whose resurgence is closely tied with population growth, urbanization and air travel. There are four closely related serotypes of dengue virus in the genus Flavivirus, family Flaviridae, and they cause more morbidity and mortality in humans than any other arboviral disease in the world today. All 4 serotypes cause disease in humans, and frequently co-circulate (hyperendemicity). Worldwide, estimates indicate that 50 to 100 million people are infected with dengue each year and between 250,000 and 500,000 dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS) cases occur each year, with case fatality rates between 1 and 5%.
Alarmingly, the incidence, distribution and severity of dengue in the Americas have dramatically increased in the last 25 years. In 1981, a major outbreak of dengue-2 virus in Cuba resulted in over ten thousand cases and 158 deaths due to DHF/DSS. A prolonged outbreak of DHF/DSS occurred in Venezuela from October 1989 until April 1990 leading to over six thousand DHF cases and 73 deaths. From 1990 to 1995 more than 26,000 cases of DHF were documented in the Americas.
Humans are infected with dengue viruses by the bite of an infective mosquito, with Aedes aegypti being the principal vector. After infection, the virus undergoes an incubation period of ~4-7 days, after which the person may present acute onset of fever accompanied by a variety of nonspecific signs and symptoms. During this acute febrile period, which may be as short as 2 days and as long as 10 days, dengue viruses may circulate in the peripheral blood. Important risk factors influencing the disease severity include the strain and serotype of the infecting virus and the immune status, age, and genetic background of the human host.
The study goal is to identify plasma protein patterns associated with the development of DHF produced by serotype 3. From these proteins, we will generate robust predictors of disease severity based on initial plasma protein measurements
Below you will find data associated with the 2D gel image analysis performed by Same Spots (Nonlinear Dynamics). There are three files available for download. The first (Venezuela PAM 2D gel Normalized Volumes.xls) includes a list of 103 normalized spot volumes that have been identified via PAM (Predictive Analysis of Microarrays) to suggest differential expression between patients infected with Dengue Fever (DF) and those infected with Dengue Hemorrhagic Fever (DHF). There are 40 DF patients and 13 DHF patients. In addition, those 103 spots have been identified via MALDI, and the resulting protein identifications are present in the second file (Venezuela Protein Identifications.pdf). The third file (Venezuela Spot numbers on 2D gel.jpg) contains a 2D gel image with the 103 spots circled so you can see where they lie on a gel.
Nikos Vasilakis, PhD, Galveston National Laboratory, Dept of Pathology, UTMB, Galveston, Ernesto Marques Jr, MD, PhD, Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, Fundação Oswaldo Cruz, Centro de Pesquisas Aggeu Magalhães, Cidade Universitaria, Recife, PE - Brasil
Significance The goal of our research is to better understand the mechanisms that allow progression to severe disease during infection with dengue virus (DENV). One of the proposed mechanisms of DENV virulence, antibody-dependent enhancement (ADE), is based on epidemiological and experimental observations where secondary infection with a heterotypic DENV is often associated with increased risk in developing severe disease due to existence of non-neutralizing heterologous antibodies. However, epidemiologic and genetic studies have indicated that intrinsic viral factors (i.e. specific genotypes and/or serotypes, viral structures, etc) may also be important indicators of DENV virulence.
Understanding the inherent host- and virus-related factors and the underlying mechanisms responsible for progression to severe disease during DENV infection has major public health implications. Although severe dengue disease may be primarily prevalent in pediatric populations, recent epidemiologic evidence suggests that adult populations are at equal risk. Although the economic burden of severe disease may be different among the affected populations, the overall cost and disability-adjusted life years (DALYs) lost are significant. Therefore identification and characterization of host predictive biological markers for dengue virulence will allow us to develop successful countermeasures - such as vaccines, therapeutics, diagnostics - and significantly reduce the overall burden of disease in hyperendemic countries.
The aim of this proposal is therefore to identify and characterize host predictive biological markers that are essential in assessing the risk of progression to severe dengue disease.
We propose to prospectively investigate the nature and breadth of host predictive biologic markers (biomarkers) responsible for progression to severe dengue disease. Our research will initially focus on human sera obtained from a well-characterized dengue patient cohort from Recife, Brazil. The projected outcome of this proposal will broaden the breadth of our understanding of the underlying mechanisms responsible for progression to severe disease during DENV infection. Most profoundly, our results will improve predictions of the risk of severe dengue disease following DENV infection in susceptible human populations in hyperendemic countries.
Below you will find data associated with the 2D gel image analysis performed by Same Spots (Nonlinear Dynamics). There are three files available for download. The first (Brazil PAM 2D gel Normalized Volumes.xls) includes a list of 122 normalized spot volumes that have been identified via PAM (Predictive Analysis of Microarrays) to suggest differential expression between patients infected with Dengue Fever (DF) and those infected with Dengue Hemorrhagic Fever (DHF). There are 30 DF patients and 22 DHF patients. In addition, those 122 spots have been identified via MALDI, and the resulting protein identifications are present in the second file (Brazil Protein Identifications.pdf). The third file (Spot numbers on 2D gel.jpg) contains a 2D gel image with the 122 spots circled so you can see where they lie on a gel.