Viral pathogenesis this lecture will define and discuss the basic principles of viral pathogenesis, the entire process by which viruses cause disease. Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience. This severe syndrome, which recently has also been. The virus belongs to the flaviviridae family, genus flavivirus, which contains several vectorborne viruses relevant for human health, such as dengue virus denv, yellow fever virus yfv, japanese encephalitis virus jev, west nile virus wnv, and tickborne encephalitis virus tbev. Denv comprise four serotypes denv 1 to 4 but are epidemiologically similar 3.
Dengue pathogenesis, clinical manifestation, lab diagnosis. Infected local cells then migrate from site of infection to lymph nodes, where monocytes and macrophages are recruited, which become targets of infection. Apr 03, 2016 this video aims to describe the mode of replication of dengue virus and the pathophysiology of dengue. Cellular receptors in human monocytes and mouse neural cells are main target for the viral infection.
Enhancement of zika virus pathogenesis by preexisting. Dengue fever, caused by infection with dengue virus, is not a new disease, but recently because of its serious emerging health threats, coupled with possible dire consequences including death, it has aroused considerable medical and public health concerns worldwide. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin rash. Infection with any of the 4 dengue virus serotypes results in a diverse range of symptoms, from mild undifferentiated fever to lifethreatening hemorrhagic fever and shock. As both cell tropism and tissue tropism of denv are considered major determinants in the pathogenesis of dengue, there is a. Comparative flavivirushost protein interaction mapping. Dengue chapter 4 2020 yellow book travelers health cdc. Generally, when we get an infection, our bodies have an immune response for antigen clearance at that time and memory for the next infection resistance in the future. Dengue viruses denv cause a spectrum of disease in humans, ranging from dengue fever df to a severe, lifethreatening syndrome called dengue hemorrhagic feverdengue shock syndrome dhfdss. Pdf dengue virus denv infections of humans were long thought to be self limited and of low mortality. Much remains to be learned about the pathogenesis of the different manifestations of dengue virus denv infections in humans. This video aims to describe the mode of replication of dengue virus and the pathophysiology of dengue. These preexisting antibodies may enhance infection with a heterologous denv serotype.
Since the second edition of dengue haemorrhagic fever. These viruses generally cause a benign syndrome, dengue fever, in the american and african tropics, and a severe syndrome, dengue hemorrhagic fever dengue shock syndrome dhfdss, in southeast asian children. Viral disease is a sum of the effects on the host of virus replication and of the immune response. There are more than 390 million new infections annually. Given that dengue virus infection elicits such a broad range of clinical symptoms, early and accurate laboratory diagnosis is essential for appropriate patient management. Pdf dengue viral infections are one of the most important mosquito borne viral infections in the world. Focusing on the pathogenesis of dengue, a pattern of acute viral infection can be seen. Role of mast cells in dengue virus pathogenesis dna and. Zika virus zikv, which is also transmitted by mosquitoes, has a replication cycle similar to denv saiz et al. Each denv has four or more genetic groups or genotypes. At present, japan is free of epidemics of dengue feverdhf, and has previously. Pdf pathogenesis of dengue viral infections researchgate. Dengue viral infections postgraduate medical journal.
Pathogenesis and pathophysiology of dengue hemorrhagic fever. Pdf autoimmune pathogenesis in dengue virus infection. Interaction with specific receptors at the cell surface is one of the first events in the pathogenesis of dengue virus. Recent evidence has provided further information of neutralizing versus enhancing monoclonal antibodies and their target epitopes on the. Dengue fever is a mosquitoborne tropical disease caused by the dengue virus. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever dhf, or dengue shock syndrome. Dengue virus after entering in the body invades the local macrophages and multiply there. The pathogenic mechanisms of dengue hemorrhagic fever and dengue shock syndrome dhfdss caused by dengue virus dv infection remain unresolved. Population growth and expansion of habitats for the viruscarrying vectorthe aedes mosquitocoupled with the ease of international travel have aligned, in space and time, populations of denguesusceptible hosts humans with circulating dengue viruses denvs and the mosquitoes that transmit. Challenges remain in understanding the basic mechanisms of viral replication and disease pathogenesis, in clinical management of patients, and in control of dengue viral transmission. Mar 19, 20 replication and transmission of dengue virus1. Following infection through the bite, cells of the hematopoietic lineage, like dendritic cells, are the first targets of dengue virus infection.
Zika virus zikv is a reemerging virus that has recently spread into dengue virus denv endemic regions and crossreactive antibodies abs could potentially affect zikv pathogenesis. Mcs are widely recognized for their immune functions and as cellular regulators of vascular integrity in human skin. Dengue is often a leading cause of illness in areas. Ppt dengue virus powerpoint presentation free to download. Nevertheless, new tools and insights have led to major recent scientific advances. This severe syndrome, which recently has also been identified.
Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Alternate hypothesis on the pathogenesis of dengue. Dengue is among the most important mosquitoborne viral disease in the world. In november 2009, the world health organization who issued a new guideline that classifies symptomatic cases as dengue or severe dengue.
Mouse models to study dengue virus immunology and pathogenesis. No other animals develop symptoms and research has been limited to studies involving humans 1. For patients presenting during the first week after fever onset, diagnostic testing should include a test for dengue virus rtpcr or ns1 and igm figure 401. Dendritic cell apoptosis and the pathogenesis of dengue. Apr 24, 2017 the importance of mast cells and their products such as cytokines and vascular endothelial growth factor vegf in the pathogenesis of dengue is emerging. Dengue chapter 4 2020 yellow book travelers health. In a mouse model, low titers of denv and wnv antibodies enhanced zikv viremia, especially in the. There are several immune cells associated with the pathogenesis of dengue virus denv infection and systemic spread, including dendritic cells, macrophages, and mast cells mcs. These viruses generally cause a benign syndrome, dengue fever, in the american and african tropics, and a severe syndrome, dengue hemorrhagic feverdengue shock syndrome dhfdss, in southeast asian children. Pathogenesis of dhfdss risk factors reported for dhf most cases of dengue fever are selflimited in their course and never progress to dengue hemorrhagic fever.
Virus infects white 3 blood cells and lymphatic tissues4. Dengue virus infection is a rapidly expanding public health problem of the tropics and subtropics. However, not all dengue infection produces dengue hemorrhagic fever. As both cell tropism and tissue tropism of denv are considered major determinants in the pathogenesis of. Current concepts in dengue pathogenesis pdf 92p this note describes about the global impact of dengue and its epidemiology, the clinical presentation of acute dengue and the pathogenesis of acute dengue infection. Dengue virusinduced er stress is required for autophagy. Aspirin free fever reducers like acetaminophen, pain medications, rest. Recent findings the pathogenesis of severe dengue is thought to be immunemediated due to the timing of the clinical manifestations and higher incidence in secondary infections with a heterologous serotype. Pathogenesis of dengue haemorrhagic fever and its impact. Annually, 100 million cases of dengue fever and half a million cases of dhf occur worldwide. Role of monocytes in the pathogenesis of dengue springerlink. Dendritic cells dcs are key antigen presenting cells, sensing pathogens, processing and. Dengue pathogenesis, clinical manifestation, lab diagnosis and treatment pathogenesis of dengue.
Clinical and laboratory diagnosis of dengue virus infection. 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. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. However, relatively little is known about these receptors.
The disease is caused by four serologically and genetically distinct viruses termed dengue virus denv 1, 2, 3 and 4. There are 2 main factors affecting severity of dengue fever. Dengue viruses cause 50 100 million cases of acute febrile disease every year. Dengue is transmitted to humans by aedes aegypti female mosquitoes. Dhf can occur in primary infection with certain genetic strains of virus. Dawn of a new era read the latest article version by scott b. Dengue virusinduced er stress is required for autophagy activation, viral replication, and pathogenesis both in vitro and in vivo. They may range from subclinical infection to dengue fever, dengue. Rhesus monkeys develop viremia similar in pattern to humans after dengue virus challenge but do not develop clinical disease. Plasma leakage and intrinsic coagulopathy are the pathological hall marks in dengue haemorrhagic fever dhf. Dengue fever is a virus, so it needs to run its course. Apr 14, 2017 antibodies against related flaviviruses such as dengue denv and west nile wnv can crossreact with zika virus zikv and could thereby increase disease severity. They may range from subclinical infection to dengue fever, dengue hemorrhagic fever dhf, and eventually dengue shock syndrome dss. Dengue fever is one of the major health problems in india.
A personalized approach to the study of pathogenesis will elucidate the basis of. The development of a compelling murine model of dengue virus denv infection has been challenging, because denv clinical isolates do not readily replicate or cause pathology in immunocompetent mice. In large part, this limitation is related to the lack of a suitable animal model of disease. In a mouse model, low titers of denv and wnv antibodies enhanced zikv viremia, especially. Ninety percent of dhf subjects are children less than 15. As both cell tropism and tissue tropism of denv are considered major determinants in the pathogenesis of dengue, there is a critical. Patients with dhfdss are characterized by several manifestations, including severe thrombocytopenia, vascular leakage, and hepatomegaly. Autoimmune pathogenesis in dengue virus infection viral. For patients presenting 1 week after fever onset, an igm test is most useful.
Antibiotics are ineffective at treating this disease. Reversely,the immune response of dengue does not resist to the next infection, but promote the severity of the disease from dengue fever to dengue hemorrhagic fever. Diseases caused by dengue virus denv are a major public health problem worldwide, considered one of the infections with more prevalence in tropical and subtropical zones of the world. However, research using immunocompromised mice andor mouseadapted viruses allows investigation of questions that may be impossible to address in. About two fifths of the worlds population lives in areas where there is a risk of dengue infection, and dengue affects 50 million people annually causing more than 25,000 deaths. Characteristics of the dengue virus the dengue virus is a single stranded rna virus belonging to the flaviviridae family. Once someone becomes infected with it, his or her symptoms are treated. Symptoms typically begin three to fourteen days after infection. Dengue is common in more than 100 countries around the world. The more dengue virus, the more target cell infection. Vectorborne flaviviruses are a source of emerging and reemerging infectious diseases.
Summary much remains to be learned about the pathogenesis of the different manifestations of dengue virus denv infections in humans. Despite the intense research in the pathogenesis of denv, this feature is not well understood. Dengue virus denv infections of humans were long thought to be selflimited and of low mortality. The advances made in those early investigations are all the. Antibodies against related flaviviruses such as dengue denv and west nile wnv can crossreact with zika virus zikv and could thereby increase disease severity.
Forty percent of the worlds population, about 3 billion people, live in areas with a risk of dengue. Population growth and expansion of habitats for the viruscarrying vectorthe aedes mosquitocoupled with the ease of international travel have aligned, in space and time, populations of denguesusceptible hosts humans with circulating dengue viruses denvs and the mosquitoes that. Nov 25, 2015 read the original article in full on fresearch. Although infection with the dengue virus denv is associated with a self. Antibodydependent enhancement of disease and severe dengue. Jun 23, 2017 zika virus zikv is a reemerging virus that has recently spread into dengue virus denv endemic regions and crossreactive antibodies abs could potentially affect zikv pathogenesis. Dengue viruses are spread to people through the bite of an infected aedes species ae.
The emergence of dengue haemorrhagic fever dhf in most tropical countries is a public health priority. In a small proportion of cases, the disease develops into severe dengue, also known as dengue. So what are the factors associated with the occurrence of dhf. Clinical findings include nausea, vomiting, rash, aches and pains, a positive tourniquet test, leukopenia, and the following. Scientific research on dengue has a long and rich history. Severe dengue most commonly occurs among infants and patients with secondary dengue virus denv infections i. The literature has been touched by famous names in medicine benjamin rush, walter reed, and albert sabin, to name a very few and has been fertile ground for medical historians. In addition, a fourth group of viruses found only in.
Dengue virus denv is the most important arboviral infection in the tropical and subtropical regions of the world affecting more than 100 countries. Dengue viruses occur as four antigenically related but distinct serotypes transmitted to humans by aedes aegypti mosquitoes. Explaining the heterogeneity between clinical presentations within a similar crosssection of the population remains a vital area of research. The importance of mast cells and their products such as cytokines and vascular endothelial growth factor vegf in the pathogenesis of dengue is emerging. Dengue viruses denv cause a spectrum of disease in humans, ranging from dengue fever df to a severe, lifethreatening syndrome called dengue hemorrhagic fever dengue shock syndrome dhfdss. Winner of the standing ovation award for best powerpoint templates from presentations magazine. This increased time corresponds to dengue virus infection of organs known to. Pathogenesis of vascular leak in dengue virus infection. Dengue viral infections are one of the most important mosquito borne diseases in the world. Current concepts in dengue pathogenesis pdf 92p download book. One of the main target cells for denv infection is monocytes. Dengue is a syndrome and its pathogenesis an interplay between virus and host factors that remains incompletely understood.
In the last 50 years, dengue incidence has increased 30fold, worldwide. Dengue virus denv is transmitted by mosquitoes and infects nearly 400 million people annually bhatt et al. In brazil, after a period of more than 30 years without. Molecular mechanism of pathogenesis of dengue virus. Dengue is the leading mosquitotransmitted viral infection in the world. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. Generally, dengue is classified as a blood infection and the. Freeaccess computer software programs are available. Pathogenesis of vascular leak in dengue virus infection malavige. Little is understood about dengue virus pathogenesis. Once inside the cell, the virus replicates and generates higher virus titers in the blood than when anti denv antibody is not present, which results in a cytokine storm and ultimately leading to more severe. Despite the global morbidity and mortality associated with denv infection, mechanisms of immune control and viral pathogenesis are poorly understood. Substantial gaps remain in the comprehensive understanding of the pathogenesis of dengue virus infections.
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