We are studying the full range of other potential health problems that zika virus infection during pregnancy may cause. Zika virus pathogenesis in rhesus macaques is unaffected. The recent spread of zikv to countries in the western hemisphere is associated with reports of microcephaly, congenital malformations, and guillainbarre syndrome. Zikv was first isolated from a nonhuman primate in 1947 and from mosquitoes in 1948 in africa, and zikv infections in humans were sporadic for half a century before emerging in the pacific and the americas. From neglected tropical disease to a focal point of international attention. Zika fever also known as zika virus disease is an illness caused by zika virus. The virus has emerged in the recent years and spread in the pacific area and the americas, where it has caused large human. Do immune responses to zika virus completely protect from reinfection.
It was not considered a relevant human pathogen until the large outbreak starting in brazil in 2015 that revealed an association of zikv infection with fetal microcephaly and guillainbarre syndrome ministerio da saude brasil 2015. After its discovery in 1947, the virus remained relatively obscure until 2015, when a large outbreak occurred in brazil and rapidly spread outward to other countries in south and central america. Epidemiology, pathogenesis and human disease article pdf available in the american journal of the medical sciences 3535 december 2016 with 390 reads how we measure reads. Here we are providing you zika virus topic for upsc mains. Zika virus zikv is primarily transmitted through mosquito bites. Although the full spectrum of zikv infection of the newborn has yet to be determined, other maternal viral infections resulting in transmission to the fetus provide instructive lessons that can be applied to the prospective evaluation of individuals with zikv. Approximately 80% of infected individuals are asymptomatic, while the remaining infected population. Pathophysiology and mechanisms of zika virus infection in the. Pdf zika virus is a mosquitoborne flavivirus discovered in uganda in 1947.
A recent outbreak of zika virus has been linked to fetal abnormalities in pregnant women who have been infected. For the first 60 years following its isolation, zika virus zikv remained a. Zikv is usually transmitted by the bite of infected mosquitoes. Incidence subsequently declined in essentially all countries and territories throughout 2017 and 2018. Zika virus zikv is a mosquitotransmitted flavivirus endemic to parts of africa and asia. From the virus research institute, entebbe, uganda. Understanding these outcomes and the factors that drive zikv pathogenesis are key. Epidemiology, virology, and pathogenesis of the zika virus. Zika virus is an emerging mosquitoborne virus that was first isolated in zika forest of uganda in 1947. Flaviviruses generally replicate in the cytoplasm, but zika virus antigens have been found in infected cell nuclei. Zika is a cause of microcephaly and other severe fetal brain defects. We find extension of a loop within the envelope protein influences stability and pathogenesis. King lecturer, has worked for the past two decades investigating how viruses work, with a goal of defining basic principles of pathogenesis and host immune. To gain preliminary insight into zikv pathology and immune responses on route of transmission, rhesus macaques rms were inoculated with zikv prvabc59 via intravaginal ivag n 3 or subcutaneous sub q n 2 routes.
Zika virus structure, symptoms, transmission, pathogenesis. Sep 21, 2019 for the first 60 years following its isolation, zika virus zikv remained a relatively poorly described member of the flaviviridae family. Understanding the pathogenesis of the emerging zika virus. Zika virus zikv was first isolated from a sentinel rhesus macaque in 1947 in the ziika forest more commonly known as the zika forest region of uganda. Zika virus was first isolated in the zika forest of uganda in 1947. The ongoing zika virus zikv epidemic and unexpected clinical outcomes, including guillainbarre syndrome and birth defects, has brought an urgent need for animal models. Pathogenesis of ocular findings in congenital zika. Since its discovery in 1947, there have been numerous outbreaks affecting many different populations. King lecturer, has worked for the past two decades investigating how viruses work, with a goal of defining basic. Currently, zika virus often can be detected during the acute phase of infection and up to 14 days after the onset of symptoms using diagnostic tests for viral rna.
What is the natural history of zika virus infectionwhen is viremia detected and cleared. Aedes mosquito is considered to be responsible for the evolutio n of t he virus. The zika virus epidemic has brought an urgent need for animal models. A strong causal association has become evident between zika virus zikv infection during pregnancy and the occurrence of fetal growth restriction, microcephaly and eye defects. This is a pdf file of an unedited manuscript that has been. A mouse model of zika virus pathogenesis sciencedirect. Mar 27, 2017 the zika virus zikv is a newly emerging pathogen that has resulted in a worldwide epidemic. Since the zika virus zikv infection outbreak in brazil in 2015 and the subsequent reported cases of congenital zika syndrome czs.
Symptoms may include fever, red eyes, joint pain, headache, and a maculopapular rash. Zika virus zikv is a mosquitoborne flavivirus that was originally discovered in 1947 dick et al. Although it was presumed to be endemic to the region based on the presence of antizikv antibodies identified during surveys of human sera, the first undisputed account of human infection was not published until 1964. To date, testing for zika cannot be done on a local. The virus has emerged in the recent years and spread in the pacific area.
Like other flaviviruses, zika virus is composed of 2 noncoding regions 5. Feb 14, 2016 the pathogenesis of the virus is hypothesized to start with an infection of dendritic cells near the site of inoculation, followed by a spread to lymph nodes and the bloodstream. Pathogenesis of zika virus infection via rectal route. Dick national institute for medical research, london. The spread of zika virus illness is of particular concern because of the complication of microcephaly in fetuses of infected mothers. The zika virus genome contains 10,794 nt encoding 3,419 aa. O ver the past several months, the zika virus has prompted the pan american health organization to issue an alert and the world health organization to declare a public health emergency. Since then, it has remained mainly in africa, with small and sporadic outbreaks in asia. In 2015, public awareness of zika virus zikv rose in response to alarming statistics of infants with. One of the hypotheses for the seemingly increased pathogenicity of zikv is that crossreactive dengue antibodies can enhance a zikv infection through the principle of antibodydependent. The zikv outbreak in the americas peaked during the first half of 2016. When present, the most common symptoms of zika fever are rash, fever, conjunctivitis, and arthralgias.
Question and answer open access understanding zika virus. The virus belongs to the flaviviridae family, which includes other flaviviruses such as dengue, yellow fever, west nile, and japanese encephalitis viruses. 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. A widespread epidemic of zika virus zikv infection was reported in 2015 from south and central america and the caribbean. Accurate diagnostic tests for zika virus infection are needed to distinguish it from other flavivirus infections and to identify women who have been infected with zika virus during pregnancy and may be at risk for developing fetal complications. Zika virus zikv is a member of flaviviridae family that has emerged as a pathogen of significant public health importance. Prior zika infection can be detected by antibodybased tests, however, these tests may also detect or crossreact with antibodies against other flaviviruses, particularly dengue virus. Pathogenesis of nonzika congenital viral infections the.
The possible role of crossreactive dengue virus antibodies. Zikv is mainly spread by the aedes aegypti mosquito and causes nonspecific symptoms such as fever. The 201516 outbreak of zika virus and congenital zika infection brought the worlds attention to links between zika infection and microcephaly. Zika virus is an arbovirus in the flavivirus family that includes yellow fever, west nile, dengue, and japanese encephalitis viruses. Zika virus pathogenesis and tissue tropism ncbi nih. Zika virus zikv is spreading rapidly into regions around the world where other flaviviruses, such as dengue denv and west nile virus wnv are endemic. In most cases, zika virus infection causes a mild, selflimited illness. Understanding the pathogenesis of zika virus infection using.
Zika virus frequently asked questions what is zika virus zika. The recent outbreak of zika virus zikv in the western hemisphere has prompted accelerated research and discovery in this area. Dec 11, 2018 zika virus zikv belongs to the flavivirus genus. The scientific community is working toward understanding zika virus pathogenesis to better manage affected women and children. Catherine spong, we discuss the aims and challenges of a forthcoming longitudinal study of a cohort of pregnant. May 08, 2019 a distinct pattern of birth defects and disabilities, called congenital zika syndrome external icon, has been found with zika virus infection during pregnancy. Zika virus pdf download ias mains important topics. Circumstantial evidence is presented in this paper in support of the hypothesis that these effects, as well as the guillainbarre syndrome, are due to an endogenous form of hypervitaminosis a resulting from zikv. Zika virus zikv is mosquitoborne emerging flavivirus which was first identified in zika forest of uganda in 1947 in rhesus monkeys. Zika virus zikv is one of a family of flaviviruses that includes west nile, dengue, yellow fever, chikungunya, japanese encephalitis and tickborne encephalitic viruses. In may 2015, the pan american health organization issued an alert. Pdf epidemiology, virology, and pathogenesis of the zika. However, since 2007, it has caused a series of increasingly severe outbreaks and is now associated with neurological symptoms such as guillainbarre syndrome and congenital zika syndrome czs. Zika virus pathogenesis and tissue tropism sciencedirect.
In this communication some studies which have been made to investigate the pathogenicity and physical properties of zika virus dick et al. It primarily spreads either through infected aedes aegypti or aedes albopictus mosquitos leading to severe neurological disorders such as microcephaly and guillainbarre syndrome in susceptible individuals. Preliminary studies on immune response and viral pathogenesis. This pattern changed in 2007, when the first major outbreak of zika virus infection. Zika virus zikv is an arbovirus belonging to the flaviviridae family. Zika virus zikv is a mosquitotransmitted flavivirus in the. Cdloop extension in zika virus envelope protein key for. The crucial period for brain development is the first trimester of pregnancy. Hostvirus interaction of zika virus in modulating disease. Triaging zika virus in pathology by elizabeth walker 24 march the aedes mosquito. It is the most recent of four surprising appearances of imperative arthropodborne viral illnesses in the western hemisphere over the preceding 20 years. Does zika virus infect or establish sanctuary in the. Zika virus is a mosquitoborne flavivirus discovered in uganda in 1947.
Pathogenesis, diagnostic challenges and treatment of zika virus. Outbreaks typically occur in tropical africa and southeast asia. Zika virus pathogenesis in rhesus macaques is unaffected by. Most cases have no symptoms, but when present they are usually mild and can resemble dengue fever. It can also be transmitted during sexual intercourse and in utero from mother to fetus.
However, zika virus is only one of the infectious causes of microcephaly and, although the contexts in which they occur vary greatly, all are of concern. Department of pathology triaging zika virus in pathology. Zika virus zikv is a mosquitoborne flavivirus originally confined to africa and asia that has spread to islands located in southeast asia, and most recently to the americas and the caribbean. 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. Zika virus was discovered in a sentinel monkey in uganda in 1947. Antibodydependent enhancement ade has been implicated in more severe forms of flavivirus. Although zika virus zikv was isolated approximately 70 years ago, few experimental studies had been published prior to 2016. For the first 60 years following its isolation, zika virus zikv remained a relatively poorly described member of the flaviviridae family. The lipid envelope is covered with dense projections that consist of a membrane and envelope glycoproteins. Resource a mouse model of zika virus pathogenesis graphical abstract highlights d development of a mouse model of zikv pathogenesis including multiple viral strains d ifnar1 mice sustain high viral burden in brain, spinal cord, and testes d zikv can establish viremia in the absence of clinical signs in mice d zikv mouse model may be useful for vaccine and antiviral. Pdf pathogenesis of zika virusassociated embryopathy. Pathogenesis and molecular mechanisms of zika virus shriddha nayak, md1 jun lei, phd1 andrew pekosz, phd2 sabra klein, phd2 irina burd, md, phd1 1department of gynecology and obstetrics, integrated research center for fetal medicine, johns hopkins university school of. Zika virus structure, genome, symptoms, transmission, pathogenesis, diagnosis. Aug 15, 2019 zika virus structure, genome, symptoms, transmission, pathogenesis, diagnosis.
Pdf zika virus zikv is a member of flaviviridae family that has emerged as a pathogen of significant public health importance. We evaluated infection and pathogenesis with contemporary and historical zikv strains in immunocompetent mice and mice lacking components of the antiviral response. Zika virus pdf download ias mains important topics hello friends welcome to. However, major complications of a zikv infection have recently become apparent for reasons that are still not fully elucidated. Blood, organ and tissue donor screening tests are also needed to assure the safety of transfusion and transplantation in areas of active mosquito. Zika virus is a newly developing virus that has been confirmed to have p otential o f spre ading acro ss a wide area. Zika virus zikv is an arthropodborne virus arbovirus in the genus flavivirus and the family flaviviridae. A number of reports have improved our understanding of. Question and answer open access understanding zika virus pathogenesis. Pathogenesis and molecular mechanisms of zika virus. Pathogens free fulltext preliminary studies on immune. Zika virus infection through mosquito bite, sexual contact, blood transfusion, or potentially other transmission routes results in asymptomatic infection in adults approximately 80% of the time.
Zika virus zikv has been known for decades to circulate in africa and asia. It can sometimes be spread by having sex with an infected partner. The pathogenesis of the virus is hypothesized to start with an infection of dendritic cells near the site of inoculation, followed by a spread to lymph nodes and the bloodstream. The mode of zikv entry into specific cell types such as. The exact pathogenesis of zika virus infection in the fetus is not fully understood. Zika virus emergence is a major concern for public health. Pathogenesis, diagnostic challenges and treatment of zika virus disease in resourcelimited settings. Structure, epidemiology, pathogenesis, symptoms, laboratory diagnosis and prevention by editorial team on january 3, 2020 in microbiology, virology the zika virus zikv is a flavivirus related to dengue, yellow fever virus, japanese encephalitis virus and west nile virus. Enhancement of zika virus pathogenesis by preexisting. Pathogenesis and molecular mechanisms of zika virus shriddha nayak, md1 jun lei, phd1 andrew pekosz, phd2 sabra klein, phd2 irina burd, md, phd1 1department of gynecology and obstetrics, integrated research.
Historically, symptomatic zika virus infections were limited to sporadic cases or small clusters of patients online technical appendix table 2. The zika virus zikv has been slowly becoming an epidemic in different parts of the world. A mouse model of zika virus pathogenesis graphical abstract highlights d development of a mouse model of zikv pathogenesis including multiple viral strains d ifnar1 mice sustain high viral burden in brain, spinal cord, and testes d zikv can establish viremia in the absence of clinical signs in mice d zikv mouse model may be useful for vaccine. Pdf understanding the pathogenesis of zika virus infection using. In may 2015, brazil reported the first outbreak of zika in the. Although many of the features seen as part of congenital zika syndrome can be caused by other infections during pregnancy, the five features listed below are rarely seen with other. Cdc recommends zika virus testing for symptomatic people living in an active zika transmission area, or who have recently traveled to an area with zika, or who have had unprotected sex with a man confirmed to have zika virus infection. Zika is a viral infection that is usually spread by the bite of an infected mosquito.
Spong abstract a recent outbreak of zika virus has been linked to fetal abnormalities in pregnant women who have been infected. Zika virus is an arthropodborne virus transmitted primarily by mosquitoes of the genus aedes. Zika virus genome biology and molecular pathogenesis. A pregnant woman already infected with zika virus can pass the virus to her fetus during the pregnancy or around the time of birth. Question and answer open access understanding zika.
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