The origins of the word dengue are not clear, but one theory is that it is derived from the swahili phrase kadinga pepo, meaning cramplike seizure caused by. There is currently no approved specific treatment or vaccine for dengue fever, and an estimated 2 billion people are at risk for being bitten by aedes. Whereas the majority of denv infections proceed asymptomatically or result in selflimited dengue fever, an increasing number of patients present more severe manifestations, such as. The mosquito immune system and the life of dengue virus. Dengue is an acute systemic viral disease that has established itself globally in both endemic and epidemic transmission cycles. Zika virus is very likely to occur in a cyclical pattern similar to that of dengue and chikungunya in the near future. The global distribution and burden of dengue nature.
The world health organizations have estimated that between 50 and 100 million people suffer from dengue fever each year. We investigated 400 cases of denguelike illness in persons hospitalized during an outbreak in al hudaydah, yemen, in 2012. Global incidence of dengue has grown dramatically in. Dengue virus is the causative agent of both classical dengue fever and the more severe dengue hemorrhage fever and dengue shock syndrome 3.
If you or a family member develops any of the these warning signs, go to a local clinic or emergency room immediately. Nevertheless, scientists understanding of dengue virus may be simplistic, as rather than distinct antigenic groups, a continuum appears to exist. Dengue virus circulating between monkeys and mosquitoes. Fully immature dengue virus particles contain a full complement of prm proteins and are noninfectious, whereas all prm proteins are cleaved in fully mature virus particles. How dengue does it dengue virus has sophisticated mechanisms for entering a cell, for replicating its rna genome, and for transcribing proteins. All four denv serotypes are prevalent in the sub tropical regions of the world and infect 50100 million individuals annually. The dengue virus is a single positive stranded rna virus belonging to the flavivirus genus of the flaviviridae family. It is a mosquitoborne, single positivestranded rna virus of the family flaviviridae. The viruses that cause dengue fever are related to those that. An infected human is bitten by a mosquito, the infected mosquito then bites another human, and the cycle continues. University of groningen dengue and chikungunya virus van. The resulting polyprotein is subsequently cleaved by. Dengue fever cases typically reach peak levels during and after the monsoon season, as the cooler and wetter conditions present ideal conditions for the viruss mosquito hosts to thrive. Oct 22, 2015 there is currently no approved specific treatment or vaccine for dengue fever, and an estimated 2 billion people are at risk for being bitten by aedes mosquitoes and infected with the dengue virus.
Dengue fever df, caused by dengue virus, is an arboviral disease characterized by an initial nonspecific febrile illness that can sometimes progress to more severe forms manifesting capillary leakage and hemorrhage dengue hemorrhagic fever, or dhf and shock dengue shock syndrome, or. What is dengue virus and how does it infect a host. Dengue fever usually starts with a fever, joint pain, rash and nausea. The monthly distribution and the proportion of denv and chikvpositive cases are shown in figure 2. Replication for many rna viruses occurs in cellular compartments mainly originated from the production and reorganization of virus induced membranes. Csf was examined sparingly due to thrombocytopenia. The other three viruses, den2, den3, and den4, are closely related to den1, but are not recognized as the same virus by. History and origin of dengue virus dengue virus net. Dengue, dengue virus, dengue hemorrhagic fever, dengue fever, flavivirus, aedes mosquitoes, dhf, df, dss. Feat provides insights into west nile, yellow fever and other flaviviruses.
The virus responsible for causing dengue, is called dengue virus denv. The disease is transmitted through the bite of an infected mosquito. Transmission of the dengue virus happens in a cycle. The goal of the study was to improve this surveillance system by assessing a modelling tool to predict the occurrence of.
Severe dengue can result in shock, internal bleeding, and even death. Watch for signs and symptoms of severe dengue to develop 2448 hours after fever goes away. Dengue fever genetic and rare diseases information. This case was attributed to the introduction of dengue virus denv. Three of these are structural proteins that form the coat of the virus and deliver the rna to target cells, and seven of them are nonstructural proteins that orchestrate the production of new viruses once the virus gets inside the cell. Time series analysis of dengue incidence in guadeloupe. Dengue virus denv belongs to the flavivirus genus of the flaviviridae family. Aedes aegypti mosquitoes are the most important vectors for the human transmission of yellow fever, which, you. Denv causes an estimated 390 million infections per year, of which about 100 million are symptomatic 1. Scientists at punebased national institute of virology, who spotted it and had been tracking it, said the new. Jungle animals in africa and southeast asia can also become bitten and infected with the. Dengue fever is the second most widespread in the world. Jun 06, 2016 the dengue virus is a single positive stranded rna virus belonging to the flavivirus genus of the flaviviridae family.
The life cycle of aedes aegypti can be completed within oneandahalf to three weeks see figure 1. Viremia for dengue 1, 2, and 3 infections ranges from barely detectable to 10 8 virions per ml for 212 days median of 45 days. In the transmission cycle, upon injection into the human body, the virus gains entry into the hosts cells, hijacks the hosts cell machinery to replicate, and escapes the hosts immune strategies to elicit pathology symptoms 1. Epidemic denguedengue haemorrhagic fever world health. Dengue, japanese encephalitis, west nile and yellow fever belong to the flavivirus genus, which is a member of the flaviviridae family.
A structural perspective of the flavivirus life cycle. Dengue fever genetic and rare diseases information center. Dengue is an acute febrile disease caused by the mosquitoborne dengue viruses denvs, consisting of four serotypes denv 1 to 4, that are members of the flaviviridae family, genus flavivirus. Learn the life cycle of this dangerous virus through this educational animation. Overall, 116 dengue and 49 chikungunya cases were diagnosed. Dengue virus infection in humans is often inapparent 1,6 but can. Dengue is a mosquitoborne infection that causes a severe flulike illness dengue fever, and sometimes a potentially lethal complication called dengue haemorrhagic fever. A new dengue virus has been confirmed for the first time in the country. Dengue virus denv 14 represents a major emerging arthropodborne pathogen. During the last decades, dengue viruses have spread throughout the americas region, with an increase in the number of severe forms of dengue. Trends for cases of dengue virus, chikungunya virus, and other dengue like viruses, al hudaydah, yemen, 2012a number of cases by monthb monthly percentages of cases by virus type.
Dengue fever dengue hemorrhagic fever dhf dengue shock syndrome threats. They are human pathogens that cause large epidemics and tens of thousands of deaths annually in many parts of the world. Rash in dengue fever is a maculopapular or macular confluent rash over the face, thorax, and flexor surfaces, with islands of skin sparing. This means that the insects goes through a complete metamorphosis with an egg, larvae, pupae, and adult stage.
Dengue viruses denvs cause the most common arthropodborne viral disease in man with 50100 million infections per year. Dengue virus is one of the most widespread mosquitoborne viruses worldwide, with an estimated annual infection rate around 390 million. Dengue virus circulating between monkeys and mosquitoes could. Factors contributing to the spread of dengue include numbers of infected and susceptible human hosts, strain of dengue virus, size of mosquito population, feeding habits, time from infection to ability to transmit virus for both vector and host, likelihood of virus transmission from human to mosquito to human, and temperature which affects. Jun 11, 2014 what is dengue virus and how does it infect a host. The cocirculation of these viruses indicates that mosquitoborne infections represent a public health threat in yemen. This study evaluated the safety and immunogenicity of a candidate recombinant, liveattenuated, tetravalent dengue vaccine cydtdv in 916 year olds in latin america. Dengue fever is a mosquitoborne tropical disease caused by the dengue virus.
More than 40% of the worlds population lives in dengue endemic areas and as many as 100 million people a year. The various steps in the flavivirus life cycle include 1 virions binding to. After about 810 days, the mosquito can transmit the virus to another human. There are four different serotypes of dengue virus denv 14. Dengue virus net is the web resource for anyone interested in dengue. Dengue fever is a dangerous and depilating disease, and its a growing threat to global health. Cocirculation of dengue and chikungunya viruses, al hudaydah. The dengue virus has sophisticated mechanisms for entering a. Zika virus may follow a cyclic pattern similar to dengue. New dengue virus confirmed in india times of india.
Five serotypes of the virus have been found, all of which can cause the full spectrum of disease. Amplification of the sylvatic cycle of dengue virus type 2, senegal. Dec 01, 2012 dengue fever df, caused by dengue virus, is an arboviral disease characterized by an initial nonspecific febrile illness that can sometimes progress to more severe forms manifesting capillary leakage and hemorrhage dengue hemorrhagic fever, or dhf and shock dengue shock syndrome, or dss. This animation shows how dengue virus infects a cell and replicates itself with the help of its hosts cellular machinery. Dengue virus life cycle youtube vti swl 04 youtube. The mosquito immune system and the life of dengue virus mdpi. Until a few hundred years ago, dengue virus was transmitted in sylvatic cycles in africa and asia between mosquitoes of the genus aedes and. Dengue virus is a small virus that carries a single strand of rna as its genome. Occasionally, and more commonly in children, the fever abates for a day and then returns, a. Albert sabin developer of the oral polio vaccine identified two serologically different viruses that cause dengue in 1944 and to date, four serotypes denv1 4 have been identified. However, doctors are noting that unusually high numbers of dengue fever cases have been reported across may and into june. How dengue virus infects cells national institutes of. Dengue virus surveillance for early warning, singapore.
Dengue virus 1 den1 was first discovered in japan in the 1940s. The symptoms are high fever, bad headache, pain behind the eyes, backache, joint pains, and sometimes a rash. Dengue virus translates, replicates and assembles new viral particles. Jungle animals in africa and southeast asia can also become bitten and infected with the virus, contributing to the spread of the disease. Dengue virus has sophisticated mechanisms for entering a cell, for replicating its rna genome, and for transcribing proteins. Mosquitoes can live and reproduce inside and outside the home. When the mosquito feeds on the blood of a person infected with dengue, the virus enters and multiplies within the mosquito. The mosquitoes that spread dengue usually breed in urban areas close to human habitation and are most active during daylight hours. Epidemic dengue fever is a very old disease, but it was characterized during most of its history by periodic, often infrequent, epidemics. Dengue virus, which causes the infectious disease dengue fever, is an rna virus that infects immune system cells. The entire life cycle, from an egg to an adult, takes approximately 810 days. Dengue is an infection caused by the dengue virus of which there are four different types serogroups.
The surveillance system in guadeloupe french west indies is currently operational for the detection of early outbreaks of dengue. Sylvatic dengue continues to flourish in southeast asia and west africa, cycling between nonhuman primates and the mosquitoes that feed on them. Pupae develop into adult flying mosquitoes in 23 days. Cocirculation of dengue and chikungunya viruses, al. The virus that causes dengue is transmitted by mosquitoes. Dengue cannot be spread from one person to another. Dengue virus life cycle and pathogenesis introduction dengue virus denv mainly transmitted by the aedes aegypti mosquito is the most common mosquitoborne viral infection worldwide. These results suggested that dengue virus may be transmitted in a fashion similar to the jungle cycle of yellow fever virus.
Dengue disease is caused by any 1 of 4 dengue virus serotypes and is a serious public health concern in latin america. It is most commonly transmitted by the mosquito vector aedes aegyptibut can replicate within and be transmitted by other members of the genus aedes including aedes albopictus figure 24. Dengue fever is a disease spread by the aedes aegypti mosquito and caused by one of four dengue viruses that are closely related. Replication for many rna viruses occurs in cellular compartments mainly originated from the production and reorganization of virusinduced membranes. As shown in the animation, the virus binds to receptors on the host cell s surface. Feb 28, 20 dengue virus has sophisticated mechanisms for entering a cell, for replicating its rna genome, and for transcribing proteins. Mosquito life cycle aedes aegypti adult eggs larva pupa the aedes mosquitoes have 4 life stages. All four denv serotypes have emerged from sylvatic strains in the forests of southeast asia. The adult life span can range from two weeks to a month depending on environmental conditions. Recovery from infection by one provides lifelong immunity. Dengue and severe dengue world health organization. Dengue a worldwide threat dengue, one of the most serious diseases affecting children in the tropics, is caused by a mosquitoborne virus related to those causing yellow fever and west nile. Life cycle of dengue mosquito aedes aegypti dengue virus net.
The rash typically begins on day 3 and persists 23 days. The denv rna genome is in the infected cell translated by the host ribosomes. Current research on dengue 39 in the americas, evidence of a forest maintenance cycle for dengue viruses is more circumstantial because field studies have not yet been carried out. All four denv serotypes are prevalent in the sub tropical regions of the world and infect 50100 million individuals. By that time, in light of the yellow fever virus transmission cycle established by haddow 5, much interest was being shown in sylvatic cycles of. Dengue virus life cycle dengue virus exists as a number of different viral forms depending on the degree of precursor membrane prm protein cleavage.
Fever typically abates with the cessation of viremia. Here is a nice graphic that depicts common life cycle elements that are generic to flaviviruses, including yellow fever virus. Samples were sent to the environmental health institute from tan tock seng hospital, which cares for. Like most arboviruses, dengue virus is maintained in nature in cycles that involve preferred. Opening doors to the possibility of developing new vaccines and antiviral agents to fight a host of insectborne diseases, scientists have, for the first time, determined the structure of a family of viruses known as the flaviviruses. Because of the lack of a vaccine and antiviral drugs, the sole measure of control is limiting the aedes mosquito vectors. Without treatment, the virus can cause damage to blood and lymph vessels and lead to dengue hemorrhagic fever, which is marked by difficulty breathing, bruising and bleeding from the nose, gums or under the skin.
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