Dengue viral infections are one of the most important mosquito borne diseases in the world. Pathogenic mechanisms include implantation of the virus at a body site, replication at the portal of entry, spread to and multiplication within target organs. Vhfs may be caused by five distinct families of rna viruses. Viral haemorrhagic fevers vhfs are extremely rare in the uk. The immune system plays a crucial role in dengue pathogenesis 25, 77. Pathogenesis of the viral hemorrhagic fevers utmb health. Interacting roles of immune mechanisms and viral load in the.
Molecular pathogenesis of viral hemorrhagic fever ncbi. Dermatologic manifestations of viral hemorrhagic fevers. For almost 50 years, ebolaviruses and related filoviruses have been repeatedly reemerging across the vast equatorial belt of the african continent to cause epidemics of highly fatal hemorrhagic fever. Vhf viruses and will not include a discussion of dengue fevers, hemorrhagic fever. Welcome to cdc stacks the role of platelets in the. Pathogenesis of bolivian hemorrhagic fever in guinea pigs. Viral hemorrhagic fevers fact sheet centers for disease control. Hemorrhagic fever viruses enter the bloodstream through various mechanisms eg, the bite of a mosquito or tick, inhalation, mucous membrane exposure, parenteral exposure, and all except hantaviruses cause disease during the period of viremia. Pdf four families of enveloped rna viruses, filoviruses, flaviviruses, arenaviruses, and bunyaviruses, cause hemorrhagic fevers. In addition to the vhf syndrome, these viruses have other common characteristics. Pathogenesis of ebola virus disease evd, formerly known as the ebola hemorrhagic fever ehf viral pathogenesis is the process by which virus infection leads to the disease.
Refer to the help section for more detailed instructions. Aug 01, 2005 pathogenesis of viral hemorrhagic fever pathogenesis of viral hemorrhagic fever bray, mike 20050801 00. Viral hemorrhagic fevers are enigmatic in when and where they cause outbreaks, and bolivian hemorrhagic fever bhf, a viral hemorrhagic fever not unlike ebola, is no exception. Viral hemorrhagic fever, any of a variety of highly fatal viral diseases that are characterized by massive external or internal bleeding or bleeding into the skin. Salvato1 1institute of human virology, university of maryland school of medicine, baltimore, maryland, united states of america, 2molecular and cellular therapeutics school of. Original antigenic sin and apoptosis in the pathogenesis of dengue hemorrhagic fever.
Exploring the immunopathogenesis of viral hemorrhagic. Viral hemorrhagic fevers vhfs refer to a group of illnesses that are caused by several distinct families of. Pathogenesis of viral hemorrhagic fever, current opinion. The role of platelets in the pathogenesis of viral. Viral hemorrhagic fevers vhfs are a group of zoonotic diseases characterized by fever and bleeding disorders that can progress to shock and death. May 29, 2017 the clinical syndrome referred to as viral hemorrhagic fever vhf can be caused by several different families of rna viruses, including select members of the arenaviruses, bunyaviruses, filoviruses, and flaviviruses. The clinical syndrome referred to as viral hemorrhagic fever vhf can be caused by several different families of rna viruses, including select members of the arenaviruses, bunyaviruses, filoviruses, and flaviviruses. Viral virulence, infection enhancing antibodies, cytokines and chemical mediators in the setting of intense immune activation are the key players implicated in the pathogenesis of dhf. Rhesus monkeys develop viremia similar in pattern to humans after dengue virus challenge but do not develop clinical disease. Travelers should not visit locations where outbreaks are occurring, avoid contact with rodents and bats, and avoid blood or body fluids of livestock in rvf and cchfendemic areas. Ninety percent of dhf subjects are children less than 15. Nov 01, 2012 although ineffective immunity and high viral loads are characteristic of several viral hemorrhagic fevers, severe plasma leakage occurs at the time of viral clearance and defervescence in dengue. Jul 02, 20 although crimeancongo hemorrhagic fever cchf is a widespread tickborne disease, little is known about its pathogenesis. The filoviruses, marburgvirus and ebolavirus, cause epidemics of haemorrhagic fever with high casefatality rates.
Other symptoms vary by the type of viral hemorrhagic fever but often include fever, malaise, muscle aches, vomiting, and shock. Although ineffective immunity and high viral loads are characteristic of several viral hemorrhagic fevers, severe plasma leakage occurs at the time of viral clearance and defervescence in dengue. The interaction of the virus with host cells is most likely. Mechanisms of disease on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Lassa fever has periodically been imported to europe, the united states, canada, and japan by travelers from west africa. The pathogenesis of this and other viral haemorrhagic fevers vhf is associated with alteration of vascular barrier function and haemorrhage, but the specific underlying mechanism is unknown. In rare cases, other viral and bacterial infections can cause a hemorrhagic fever. The interaction of the virus with host cells is most likely responsible for the pathogenesis of cchf. Pathogenesis of the viral hemorrhagic fevers annual. These highly infectious viruses lead to a potentially lethal disease syndrome characterized by fever, malaise, vomiting, mucosal and gastrointestinal gi bleeding, edema, and hypotension.
Viral hemorrhagic fevers chapter 4 2020 yellow book. Pathogenesis of viral hemorrhagic fever pathogenesis of viral hemorrhagic fever bray, mike 20050801 00. Substantial gaps remain in the comprehensive understanding of the pathogenesis of dengue virus infections. Molecular pathogenesis of viral hemorrhagic fever springerlink. Pathogenesis of viral hemorrhagic fever sciencedirect. Viral hemorrhagic fevers vhfs refer to a group of illnesses that are caused by several distinct families of viruses. Viral rna was quantified by realtime reversetranscriptase polymerase chain reaction. Although pathophysiology may differ for each factor of the viral hemorrhagic fever, major common features such as microvascular disease and disruption of hemostasis come to the forefront 23.
Dengue viral infections postgraduate medical journal. Review the role of platelets in the pathogenesis of viral hemorrhagic fevers juan c. Diagnostics and discovery in viral hemorrhagic fevers. Humanized mouse models in viral hemorrhagic fever vhf research.
In general, the term viral hemorrhagic fever is used to describe a. Crimeancongo haemorrhagic fever cchf disease in humans shows a spectrum of severity, from mild to acute. Hemorrhagic fever caused by a novel bunyavirus in china. The concept of viral hemorrhagic fever vhf was originated in the 1930s by soviet investigators, who were. Pdf pathogenesis of the viral hemorrhagic fevers moises reuel. Singlestranded rna viruses from four different families cause a syndrome of fever and malaise, capillary leak with loss of plasma volume, and coagulation defects which can lead to bleeding. T cell responses to an hlab07restricted epitope on the dengue ns3 protein correlate with disease severity. Bhf is caused by machupo virus macv, a south american hemorrhagic fever virus that is often hard to distinguish from other hemorrhagic fevers in the region.
Although many viral infections have on occasion been associated with hemorrhagic complications, infection with any of several rna viruses regularly results in vascular involvement and the syndrome called viral hemorrhagic fever vhf. Pathogenesis of filoviral haemorrhagic fevers the lancet. They are caused by different groups of viruses from the families flaviviridae, bunyaviridae, arenaviridae, and filoviridae. Abstract although crimeancongo hemorrhagic fever cchf is a widespread tickborne disease, little is known about its pathogenesis. Author summary kyasanur forest disease virus kfdv and alkhumra hemorrhagic fever virus ahfv are tickborne flaviviruses that cause severe hemorrhagic disease in humans. However, they can occur in returning travellers and should be in the differential diagnosis for cases of unexplained fever in a returning traveller from a relevant area. The hemorrhagic fever the diseases, the cell and organ tropism of the concept of vhf includes diseases caused by 23 viruses, and the pathogenic and. Interacting roles of immune mechanisms and viral load in. Viral hemorrhagic fevers vhf are acute zoonotic diseases that, early on, seem to cause platelet destruction or dysfunction. The severe illness results from a complex of pathogenetic mechanisms that enable the virus to suppress innate and adaptive immune responses, infect and kill a broad variety of cell types, and elicit strong inflammatory responses and disseminated intravascular coagulation, producing. Pathogenesis of dengue haemorrhagic fever and its impact. Four families of enveloped rna viruses, filoviruses, flaviviruses, arenaviruses, and bunyaviruses, cause hemorrhagic fevers.
However, it has been hypothesized that it could be a result of the direct injury of virusinfected tissues in combination with the indirect effects of host immune responses, including cytokines. Recovery from evd requires an early, transient and controlled inflammatory response, which helps control virus replication and spread while sim. N2 four families of enveloped rna viruses, filoviruses, flaviviruses, arenaviruses, and bunyaviruses, cause hemorrhagic fevers. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever dhf, or dengue shock syndrome. Epidemiology and pathogenesis of ebola virus disease. The role of heparan sulphate in pathogenesis of crimean. Although ineffective immunity and high viral loads are characteristic of several viral hemorrhagic fevers, severe plasma leakage occurs at the time. Much remains to be learned about the pathogenesis of the different manifestations of dengue virus denv infections in humans. Although direct cytopathic effects can contribute to disease severity, most features of. Annually, 100 million cases of dengue fever and half a million cases of dhf occur worldwide. The pathogenesis of viral hemorrhagic fevers shows similarity 22, 23. In spite of clinically useful similarities among various vhfs, there are significant differences in their.
Viral hemorrhagic fevers vhfs are a group of febrile illnesses caused by rna viruses from several viral families. The demise of the patient occurs due to severe inflammation, multiorgan dysfunction syndrome and haemorrhage associated with a poorly defined coagulopathy. The main contributors are endothelial cells ecs and immune cells. What carries virus es that cause viral hemorrhagic fevers. Viral hemorrhagic fevers vhfs are a diverse group of animal and human illnesses in which fever and hemorrhage are caused by a viral infection. Pathogenesis and pathophysiology of dengue hemorrhagic fever. Ian lipkin, gustavo palacios, and thomas briese center for infection and immunity, mailman school of public health of columbia university, new york, new york, usa. There are 2 theories underlying the cchf pathogenesis. Viral hemorrhagic fevers fact sheet centers for disease. Epidemiology and pathogenesis of ebola virus disease uptodate.
Jun 12, 2014 viral hemorrhagic fevers vhfs are a group of zoonotic diseases characterized by fever and bleeding disorders that can progress to shock and death. Although ineffective immunity and high viral loads are characteristic of several viral hemorrhagic fevers, severe plasma leakage occurs at the time of viral. Ninety percent of dhf subjects are children less than 15 years of age. These viruses are maintained in specific natural cycles involving nonhuman primates, bats, rodents, domestic ruminants, humans, mosquitoes, and ticks. The severe illness results from a complex of pathogenetic mechanisms that enable the virus to suppress innate and adaptive immune responses, infect and kill a broad variety of cell types, and elicit strong inflammatory responses and disseminated intravascular coagulation. Vhf is characterized by malaise, fever, vascular permeability, decreased plasma volume, coagulation abnormalities, and varying degrees of hemorrhage. Vascular instability varies from mild to fatal shock, and hemorrhage ranges from none to life threatening. The clinical manifestations, diagnosis, treatment, and prevention of ebola virus disease are discussed elsewhere. Despite sharing a high degree of genetic sequence similarity, kfdv replicates primarily in the brain and is. Viral hemorrhagic fevers fact sheet what are viral hemorrhagic fevers. Blood levels of a range of cytokines, chemokines, and acute phase proteins were assayed.
The 202015 west african epidemic, by far the most geographically extensive, most fatal, and longest lasting epidemic in ebolas history, presented an enormous international public health. Pathogenesis of crimeancongo hemorrhagic fever vector. Viral hemorrhagic fevers vhfs refer to a group of illnesses caused by. A viral hemorrhagic fever is an alternate theory of the cause of the black death and the plague of justinian. Comparative pathogenesis of alkhumra hemorrhagic fever and. Interacting roles of immune mechanisms and viral load in the pathogenesis of crimeancongo hemorrhagic fever ana saksida, 1darja duh, branka wraber,1 isuf dedushaj,2 salih ahmeti,3 and tatjana avs.
They may range from subclinical infection to dengue fever, dengue hemorrhagic fever dhf, and eventually dengue shock syndrome dss. Thus, understanding of the pathogenesis is important in planning of the treatment. Although they differ in some features, all of these illnesses are characterized by fever and malaise, increased vascular permeability leading to a. Ribavirin, an anti viral drug, has been effective in treating some individuals with lassa fever or hfrs. American hemorrhagic fevers caused by arenaviruses, but only in a small minority of patients with dengue, rift valley fever, and lassa fever.
The pathogenesis of the disease is still not very well understood mostly due to the lack of suitable animal models. Plasma leakage and intrinsic coagulopathy are the pathological hall marks in dengue haemorrhagic fever dhf. Pdf pathogenesis and pathophysiology of dengue hemorrhagic. The initial, and currently only, outbreak of lujo virus in septemberoctober 2008 left 45 patients dead. These highly infectious viruses lead to a potentially lethal disease syndrome characterized by fever, malaise, vomiting, mucosal and gastrointestinal gi. Mar 16, 2017 viral hemorrhagic fevers vhfs are a group of febrile illnesses caused by rna viruses from several viral families. In spite of clinically useful similarities among various vhfs, there are significant differences in their pathogenesis and clinical. Comparative pathogenesis of crimeancongo hemorrhagic fever.
Although crimeancongo hemorrhagic fever cchf is a widespread tickborne disease, little is known about its pathogenesis. Crimeancongo hemorrhagic fever cchf virus has been called the asian ebola virus an epithet that recognizes the close clinical resemblance of cchf and ebola hemorrhagic fever ehf, and also suggests that the two illnesses share similar underlying mechanisms 38. To shed more light on the role of viral load and cytokines, differential influences of cchf virus. Pathogenesis of viral hemorrhagic fever, current opinion in. Until now, the pathogenesis of crimeancongo hemorrhagic fever cchf has not been well described. Pathogenesis diagnosis medical management prevention and control summary director, national institute of allergies and infectious diseases, integrated research facility, national institutes of health, 6700a rockledge drive. Here we present the four major ways viruses affect platelet development and function and new evidence of molecular factors that are preferentially induced by the more pathogenic members of the families flaviviridae, bunyaviridae, arenaviridae, and filoviridae. A viral hemorrhagic fever is a possible cause of the plague of athens during the peloponnesian war. In general, the term viral hemorrhagic fever is used to describe a severe multisystem syndrome multisystem in that multiple organ systems in the body are affected. Immunology and pathogenesis of viral hemorrhagic fevers diagnostics and discovery in viral hemorrhagic fevers w. In addition to the vhf syndrome, these viruses have other common.
Although many viral infections have on occasion been associated with hemorrhagic com plications, infection with any of several rna viruses regularly results in. The term viral hemorrhagic fever vhf designates a group of diseases, caused by enveloped, singlestranded rna viruses from four different virus families, that are acquired through contact with animals or the bite of an infected arthropod. Ebola viral haemorrhagic fever is rare but the lifethreatening haemorrhagic disorder associated with ebola viral sepsis. Also, the mortality of viral hemorrhagic fever appears to be higher in pregnancy. The clinical syndrome referred to as viral hemorrhagic fever vhf can be caused several different families of rna viruses, including select. Download the annals of the new york academy of sciences app from the apple store. Comparative pathogenesis of crimeancongo hemorrhagic. In large part, this limitation is related to the lack of a suitable animal model of disease. Pathogenesis of the viral hemorrhagic fevers, annual. In general, the term viral hemorrhagic fever is used to describe a severe multisystem syndrome. A total of 49 patients with hemorrhagic fever caused by hysv were included.
Viral hemorrhagic fever should be suspected in patients who live in or who have returned from locations of viral occurrence if they have severe fever and evidence of vascular involvement eg, subnormal blood pressure, postural hypotension, petechiae, easy bleeding, flushing, nondependent edema. S1 immunology and pathogenesis of viral hemorrhagic fevers. The pathogenic mechanisms are extremely diverse and include deficiency of hepatic synthesis of. Select up to three search categories and corresponding keywords using the fields to the right. Viral hemorrhagic fevers vhfs refer to a group of illnesses that are caused by.
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