Hantavirus: Difference between revisions
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The word ''hantavirus'' is derived from the Hantan River, where the Hantaan virus (the etiologic agent of Korean hemorrhagic fever) was first isolated by Dr. Lee Ho-Wang. The disease associated with Hantaan virus is called '''Korean hemorrhagic fever''' (a term that is no longer in use) or '''hemorrhagic fever with renal syndrome''' (HFRS), a term that is accepted by the World Health Organization. | The word ''hantavirus'' is derived from the Hantan River, where the Hantaan virus (the etiologic agent of Korean hemorrhagic fever) was first isolated by Dr. Lee Ho-Wang. The disease associated with Hantaan virus is called '''Korean hemorrhagic fever''' (a term that is no longer in use) or '''hemorrhagic fever with renal syndrome''' (HFRS), a term that is accepted by the World Health Organization. | ||
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==Virology== | ==Virology== | ||
Revision as of 14:40, 10 August 2015
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Diagnosis |
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Treatment |
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Case Studies |
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Hantavirus On the Web |
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American Roentgen Ray Society Images of Hantavirus |
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 Transmission electron micrograph of the Sin Nombre Hantavirus
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Andes virus (ANDV) |
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WikiDoc Resources for Hantavirus |
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Articles |
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Most recent articles on Hantavirus |
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Media |
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Evidence Based Medicine |
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Clinical Trials |
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Ongoing Trials on Hantavirus at Clinical Trials.gov Clinical Trials on Hantavirus at Google
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Guidelines / Policies / Govt |
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US National Guidelines Clearinghouse on Hantavirus
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Books |
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News |
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Commentary |
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Definitions |
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Patient Resources / Community |
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Patient resources on Hantavirus Discussion groups on Hantavirus Patient Handouts on Hantavirus Directions to Hospitals Treating Hantavirus Risk calculators and risk factors for Hantavirus
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Healthcare Provider Resources |
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Causes & Risk Factors for Hantavirus |
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Continuing Medical Education (CME) |
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International |
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Business |
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Experimental / Informatics |
Overview
Hantaviruses belong to the bunyaviridae family of viruses. There are 5 genera within the bunyaviridae family: bunyavirus, phlebovirus, nairovirus, tospovirus, and hantavirus. Each is made up of negative-sensed, single-stranded RNA viruses. All these genera include arthropod-borne viruses, with the exception of hantavirus, which is a genus of rodent-borne agents.
The word hantavirus is derived from the Hantan River, where the Hantaan virus (the etiologic agent of Korean hemorrhagic fever) was first isolated by Dr. Lee Ho-Wang. The disease associated with Hantaan virus is called Korean hemorrhagic fever (a term that is no longer in use) or hemorrhagic fever with renal syndrome (HFRS), a term that is accepted by the World Health Organization.
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Virology
Like other members of the bunyavirus family, hantaviruses are enveloped viruses with a genome that consists of three single-stranded RNA segments designated S (small), M (medium), and L (large). All hantaviral genes are encoded in the negative (genome complementary) sense. The S RNA encodes the nucleocapsid (N) protein. The M RNA encodes a polyprotein that is cotranslationally cleaved to yield the envelope glycoproteins G1 and G2. The L RNA encodes the L protein, which functions as the viral transcriptase/replicase. Within virions, the genomic RNAs of hantaviruses are thought to complex with the N protein to form helical nucleocapsids, the RNA component of which circularizes due to sequence complementarity between the 5' and 3' terminal sequences of each genomic segment.
Hantaviruses replicate exclusively in the host cell cytoplasm. Entry into host cells is thought to occur by attachment of virions to cellular receptors and subsequent endocytosis. Nucleocapsids are introduced into the cytoplasm by pH-dependent fusion of the virion with the endosomal membrane. Transcription of viral genes must be initiated by association of the L protein with the three nucleocapsid species. In addition to transcriptase and replicase functions, the viral L protein is also thought to have an endonuclease activity that cleaves cellular messenger RNAs (mRNAs) for the production of capped primers used to initiate transcription of viral mRNAs. As a result of this "cap snatching," the mRNAs of hantaviruses are capped and contain nontemplated 5' terminal extensions. The G1 (aka Gn) and G2 (Gc) glycoproteins form hetero-oligomers and are then transported from the endoplasmic reticulum to the Golgi complex, where glycosylation is completed. The L protein produces nascent genomes by replication via a positive-sense RNA intermediate. Hantavirus virions are believed to assemble by association of nucleocapsids with glycoproteins embedded in the membranes of the Golgi, followed by budding into the Golgi cisternae. Nascent virions are then transported in secretory vesicles to the plasma membrane and released by exocytosis.
Symptoms
Hemorrhagic Fever with Renal Syndrome (HFRS)
Hantavirus has an incubation time of 2-4 weeks in humans, before symptoms of infection occur. These symptoms can be split into five phases:
- Febrile phase: Symptoms include fever, chills, malaise, headaches, nausea, abdominal and back pain, respiratory problems such as the ones common in the influenza virus, as well as gastro-intestinal problems. These symptoms normally occur for 3-7days.
- Hypotensive phase: This occurs when the blood platelet levels drop and symptoms can lead to tachycardia and hypoxemia. This phase can last for 2 days.
- Oliguric phase: This phase lasts for 3-7 days and is characterised by the onset of renal failure and proteinuria occurs.
- Diuretic phase: This is characterized by diuresis of 3-6L per day, which can last for a couple of days up to weeks.
- Convalescent phase: This is normally when recovery occurs and symptoms begin to improve.
Hantavirus (Cardio-)Pulmonary Syndrome (HPS or HCPS)
Hantavirus pulmonary syndrome (HPS) is a deadly disease transmitted by infected rodents through urine, droppings, or saliva. Humans can contract the disease when they breathe in aerosolized virus. HPS was first recognized in 1993 and has since been identified throughout the United States. Although rare, HPS is potentially deadly. Rodent control in and around the home remains the primary strategy for preventing hantavirus infection.
These symptoms, which are very similar to HFRS, include tachycardia and tachypnoea. Such conditions can lead to a cardiopulmonary phase, where cardiovascular shock can occur, and hospitalization of the patient is required.
Treatment
- Hanta virus treatment[1]
- Supportive therapy
- ICU management should include careful assessment, monitoring and adjustment of volume status and cardiac function, including inotropic and vasopressor support if needed.
- Fluids should be administered carefully due to the potential for capillary leakage.
- Supplemental oxygen should be administered if patients become hypoxic.
- Equipment and materials for intubation and mechanical ventilation should be readily available since onset of respiratory failure may be precipitous.
- Note (1): There is no specific treatment or cure for hantavirus infection.
- Note (2): Treatment of patients with HPS remains supportive in nature.
- Note (3): Patients should receive appropriate, broad-spectrum antibiotic therapy while awaiting confirmation of a diagnosis of HPS. Care during the initial stages of the disease should include antipyretics and analgesia as needed.
- Note (4): If there is a high degree of suspicion of Hantavirus pulmonary syndrome, patients should be immediately transferred to an emergency department or intensive care unit (ICU) for close monitoring and care.
- Note (5): if the individual is experiencing fever and fatigue and has a history of potential rural rodent exposure, together with shortness of breath, would be strongly suggestive of Hantavirus pulmonary syndrome.
External links
- "Hantaviruses, with emphasis on Four Corners Hantavirus" by Brian Hjelle, M.D., Department of Pathology, School of Medicine, University of New Mexico
- CDC's Hantavirus Information page
- Kruger DH, Ulrich R, Lundkvist A (2001) "Hantavirus infections and their prevention", Microbes And Infection 3 (13): 1129-1144