VIRAL haemorrhagic fevers .docx

8/14/2019 VIRAL haemorrhagic fevers .docx

1/3

VIRALHEMORRHAGICFEVERS

Theviralhemorrhagic (or haemorrhagic)fevers (VHFs) are a diverse group of animal and

human illnesses that may be caused by five distinct families ofRNA viruses:the

familiesArenaviridae,Filoviridae,Bunyaviridae,Flaviviridae,andRhabdoviridae. All types of

VHF are characterized by fever and bleeding disorders and all can progress to high fever, shockand death in many cases. Some of the VHF agents cause relatively mild illnesses, such as the

Scandinaviannephropathia epidemica,while others, such as the AfricanEbola virus,can cause

severe, life-threatening disease

Five families of RNA viruses have been recognised as being able to cause this syndrome.

The familyArenaviridaeinclude the viruses responsible forLassa fever,Lujovirus,Argentine,Bolivian,Brazilian andVenezuelan hemorrhagic fevers.

The familyBunyaviridaeinclude the members of theHantavirusgenus thatcausehemorrhagic fever with renal syndrome (HFRS), theCrimean-Congo hemorrhagicfever(CCHF) virus from theNairovirusgenus,Garissa virus andIlesha virus from

theOrthobunyavirusand theRift Valley fever (RVF) virus from thePhlebovirusgenus.

The familyFiloviridaeincludeEbola virus andMarburg virus. The familyFlaviviridaeincludedengue,yellow fever,and two viruses in thetick-borne

encephalitis group that cause VHF:Omsk hemorrhagic fever virus andKyasanur Forest

disease virus.

In September 2012 scientists writing in the journalPLOS Pathogens reported the isolation ofa member of theRhabdoviridaeresponsible for 2 fatal and 2 non-fatal cases of hemorrhagic

fever in the Bas-Congo district of the Democratic Republic of Congo. The non-fatal cases

occurred in healthcare workers involved in the treatment of the other two, suggesting the

possibility of person-to-person transmission.[1]This virus appears to be unrelated topreviously known Rhabdoviruses.

Clinical and treatment aspects

Signs and symptoms of VHFs include (by definition)fever andbleeding diathesis.

Manifestations of VHF often also include flushing of the face and chest,petechiae,frank

bleeding, edema,hypotension,and shock. Malaise,myalgias,headache, vomiting, and diarrhea

occur frequently. Definitive diagnosis is usually made at a reference laboratory with

advancedbiocontainment capabilities.

The findings of laboratory investigation vary somewhat between the viruses but in general there

is a decrease in the total white cell count particularly thelymphocytes,a decrease intheplatelet count, an increase in theserumliverenzymes as well as increase in both the

prothrombin (PT) and activated partial thromboplastin times (PTT). The hematocrit may be

elevated. The serum urea and creatine may be raised but this is dependent on the hydration status

of the patient. The bleeding time tends to be prolonged.

Medical management of VHF patients may require intensive supportive care. Antiviral therapy

with intravenousribavirin may be useful in Bunyaviridae and Arenaviridae infections
http://en.wikipedia.org/wiki/Virushttp://en.wikipedia.org/wiki/Hemorrhagehttp://en.wikipedia.org/wiki/Feverhttp://en.wikipedia.org/wiki/Virushttp://en.wikipedia.org/wiki/Hemorrhagehttp://en.wikipedia.org/wiki/Feverhttp://en.wikipedia.org/wiki/RNA_virushttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Nephropathia_epidemicahttp://en.wikipedia.org/wiki/Nephropathia_epidemicahttp://en.wikipedia.org/wiki/Nephropathia_epidemicahttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/Lassa_feverhttp://en.wikipedia.org/wiki/Lujo_virushttp://en.wikipedia.org/wiki/Lujo_virushttp://en.wikipedia.org/wiki/Argentine_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Bolivian_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Brazilian_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Venezuelan_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Hantavirushttp://en.wikipedia.org/wiki/Hantavirushttp://en.wikipedia.org/wiki/Hantavirushttp://en.wikipedia.org/wiki/Hemorrhagic_fever_with_renal_syndromehttp://en.wikipedia.org/wiki/Crimean-Congo_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Crimean-Congo_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Nairovirushttp://en.wikipedia.org/wiki/Nairovirushttp://en.wikipedia.org/wiki/Nairovirushttp://en.wikipedia.org/w/index.php?title=Garissa_virus&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Ilesha_virus&action=edit&redlink=1http://en.wikipedia.org/wiki/Orthobunyavirushttp://en.wikipedia.org/wiki/Orthobunyavirushttp://en.wikipedia.org/wiki/Orthobunyavirushttp://en.wikipedia.org/wiki/Rift_Valley_feverhttp://en.wikipedia.org/wiki/Phlebovirushttp://en.wikipedia.org/wiki/Phlebovirushttp://en.wikipedia.org/wiki/Phlebovirushttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Marburg_virushttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Denguehttp://en.wikipedia.org/wiki/Yellow_feverhttp://en.wikipedia.org/wiki/Tick-borne_encephalitishttp://en.wikipedia.org/wiki/Tick-borne_encephalitishttp://en.wikipedia.org/wiki/Omsk_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Kyasanur_Forest_diseasehttp://en.wikipedia.org/wiki/Kyasanur_Forest_diseasehttp://en.wikipedia.org/wiki/PLOS_Pathogenshttp://en.wikipedia.org/wiki/Rhabdoviridaehttp://en.wikipedia.org/wiki/Rhabdoviridaehttp://en.wikipedia.org/wiki/Rhabdoviridaehttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-Grard2012-1http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-Grard2012-1http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-Grard2012-1http://en.wikipedia.org/wiki/Feverhttp://en.wikipedia.org/wiki/Bleeding_diathesishttp://en.wikipedia.org/wiki/Petechiaehttp://en.wikipedia.org/wiki/Edemahttp://en.wikipedia.org/wiki/Hypotensionhttp://en.wikipedia.org/wiki/Myalgiahttp://en.wikipedia.org/wiki/Biocontainmenthttp://en.wikipedia.org/wiki/Lymphocytehttp://en.wikipedia.org/wiki/Platelethttp://en.wikipedia.org/wiki/Blood_serumhttp://en.wikipedia.org/wiki/Liverhttp://en.wikipedia.org/wiki/Enzymehttp://en.wikipedia.org/wiki/Ribavirinhttp://en.wikipedia.org/wiki/Ribavirinhttp://en.wikipedia.org/wiki/Enzymehttp://en.wikipedia.org/wiki/Liverhttp://en.wikipedia.org/wiki/Blood_serumhttp://en.wikipedia.org/wiki/Platelethttp://en.wikipedia.org/wiki/Lymphocytehttp://en.wikipedia.org/wiki/Biocontainmenthttp://en.wikipedia.org/wiki/Myalgiahttp://en.wikipedia.org/wiki/Hypotensionhttp://en.wikipedia.org/wiki/Edemahttp://en.wikipedia.org/wiki/Petechiaehttp://en.wikipedia.org/wiki/Bleeding_diathesishttp://en.wikipedia.org/wiki/Feverhttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-Grard2012-1http://en.wikipedia.org/wiki/Rhabdoviridaehttp://en.wikipedia.org/wiki/PLOS_Pathogenshttp://en.wikipedia.org/wiki/Kyasanur_Forest_diseasehttp://en.wikipedia.org/wiki/Kyasanur_Forest_diseasehttp://en.wikipedia.org/wiki/Omsk_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Tick-borne_encephalitishttp://en.wikipedia.org/wiki/Tick-borne_encephalitishttp://en.wikipedia.org/wiki/Yellow_feverhttp://en.wikipedia.org/wiki/Denguehttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Marburg_virushttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Phlebovirushttp://en.wikipedia.org/wiki/Rift_Valley_feverhttp://en.wikipedia.org/wiki/Orthobunyavirushttp://en.wikipedia.org/w/index.php?title=Ilesha_virus&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Garissa_virus&action=edit&redlink=1http://en.wikipedia.org/wiki/Nairovirushttp://en.wikipedia.org/wiki/Crimean-Congo_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Crimean-Congo_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Hemorrhagic_fever_with_renal_syndromehttp://en.wikipedia.org/wiki/Hantavirushttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Venezuelan_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Brazilian_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Bolivian_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Argentine_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Lujo_virushttp://en.wikipedia.org/wiki/Lujo_virushttp://en.wikipedia.org/wiki/Lassa_feverhttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Nephropathia_epidemicahttp://en.wikipedia.org/wiki/Flaviviridaehttp://en.wikipedia.org/wiki/Bunyaviridaehttp://en.wikipedia.org/wiki/Filoviridaehttp://en.wikipedia.org/wiki/Arenaviridaehttp://en.wikipedia.org/wiki/RNA_virushttp://en.wikipedia.org/wiki/Feverhttp://en.wikipedia.org/wiki/Hemorrhagehttp://en.wikipedia.org/wiki/Virushttp://en.wikipedia.org/wiki/Feverhttp://en.wikipedia.org/wiki/Hemorrhagehttp://en.wikipedia.org/wiki/Virus


2/3

(specifically Lassa fever, RVF, CCHF, and HFRS due to Old World Hantavirus infection) and

can be used only under an experimental protocol asinvestigational new drug (IND) approved by

theU.S. Food and Drug Administration(FDA). Interferon may be effective in Argentine or

Bolivian hemorrhagic fevers (also available only as IND). Experimental vaccines for other VHFs

are not readily available.

Prophylactic (preventive) ribavirin may be effective for some bunyavirus and arenavirus

infections (again, available only as IND).

VHF isolation guidelines dictate that all VHF patients (with the exception of dengue patients)

should be cared for using strict contact precautions, including hand hygiene, double gloves,

gowns, shoe and leg coverings, and faceshield or goggles. Lassa, CCHF, Ebola, and Marburg

viruses may be particularly prone tonosocomial (hospital-based) spread. Airborne precautions

should be utilized including, at a minimum, a fit-tested, HEPA filter-equipped respirator (such as

an N-95 mask), a battery-powered, air-purifying respirator, or a positive pressure supplied air

respirator to be worn by personnel coming within six feet of a VHF patient. Multiple patients

should be cohorted (sequestered) to a separate building or a ward with an isolated air-handling

system. Environmental decontamination is typically accomplished with hypochlorite or phenolicdisinfectants.

[2]

Pathophysiology

The diversity of clinical features seen among the VHF infections probably originates from

varying mechanisms of pathogenesis. An immunopathogenic mechanism, for example, has been

identified fordengue hemorrhagic fever,which usually occurs among patients previously

infected with a heterologous dengue serotype. An influential theory explaining this phenomenon

is called antibody-dependent enhancement. In contrast,disseminated intravascular

coagulation (DIC) is thought to underlie the hemorrhagic features of Rift Valley, Marburg and

Ebola fevers. In most VHFs, however, the etiology of the coagulopathy is most likelymultifactorial (e.g., hepatic damage, consumptive coagulopathy, primary marrow dysfunction,

etc.).

The reasons for variation among patients infected with the same virus are unknown but stem

from a complex system of virus-host interactions. Moreover, why some infected persons develop

full-blown VHF while others do not also remains an unresolved issue. Virulence of the infecting

agent clearly plays an important role. The VHF syndrome (capillary leak, bleeding diathesis

and hemodynamic compromise leading to shock) occurs in a majority of patients manifesting

disease from filoviruses, CCHF, and the South American hemorrhagic fever viruses, while it

occurs in a small minority of patients with dengue, RVF and Lassa fever.

Biowarfare/bioterrorism potential

The VHF viruses are spread in a variety of ways. Some may be transmitted to humans through a

respiratory route. Although evidence for a history of weaponization (development into

abiological weapon)does not exist for many of these viruses, all are considered by military

medical planners to have a potential for aerosol dissemination, weaponization, or likelihood for

confusion with similar agents that might be weaponized.[3][4]
http://en.wikipedia.org/wiki/Investigational_new_drughttp://en.wikipedia.org/wiki/Food_and_Drug_Administration_(United_States)http://en.wikipedia.org/wiki/Nosocomialhttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-2http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-2http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-2http://en.wikipedia.org/wiki/Dengue_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Antibody_dependent_enhancementhttp://en.wikipedia.org/wiki/Antibody_dependent_enhancementhttp://en.wikipedia.org/wiki/Antibody_dependent_enhancementhttp://en.wikipedia.org/wiki/Disseminated_intravascular_coagulationhttp://en.wikipedia.org/wiki/Disseminated_intravascular_coagulationhttp://en.wikipedia.org/wiki/Biological_weaponhttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-3http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-3http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-3http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-3http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-3http://en.wikipedia.org/wiki/Biological_weaponhttp://en.wikipedia.org/wiki/Disseminated_intravascular_coagulationhttp://en.wikipedia.org/wiki/Disseminated_intravascular_coagulationhttp://en.wikipedia.org/wiki/Antibody_dependent_enhancementhttp://en.wikipedia.org/wiki/Dengue_hemorrhagic_feverhttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-2http://en.wikipedia.org/wiki/Nosocomialhttp://en.wikipedia.org/wiki/Food_and_Drug_Administration_(United_States)http://en.wikipedia.org/wiki/Investigational_new_drug


3/3

Notable VHF outbreaks

Cocoliztli in New Mexico 1545. The GreatYellow Fever Epidemic of 1793 in Philadelphia, PA USA. Nearly 10% of the

population of 50,000 succumbed to the disease.

Mkambo inGabon is the site of several outbreaks ofEbola virus disease. Orientale Province,Democratic Republic of the Congo villages ofDurba andWatsa were the

epicenter of the 19982000 outbreak ofMarburg virus disease.

Uge Province inAngola is the site of world's worst hemorrhagic feverepidemic,whichoccurred in 2005.

A VHF outbreak in the village ofMweka, Democratic Republic of the Congo (DRC) thatstarted in August 2007, and that has killed 103 people (100 adults and three children), has

been shown to be caused (at least partially) byEbola virus.

A viral hemorrhagic fever is a possible cause of thePlague of Athens duringthePeloponnesian War.

[10]

The initial, and currently only, outbreak ofLujo virus in September-October 2008 left 4/5patients dead.

[11]
http://en.wikipedia.org/wiki/Yellow_Fever_Epidemic_of_1793http://en.wikipedia.org/wiki/M%C3%A9kambohttp://en.wikipedia.org/wiki/Gabonhttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Orientale_Provincehttp://en.wikipedia.org/wiki/Democratic_Republic_of_the_Congohttp://en.wikipedia.org/wiki/Durba,_Democratic_Republic_of_the_Congohttp://en.wikipedia.org/wiki/Watsahttp://en.wikipedia.org/wiki/Marburg_virushttp://en.wikipedia.org/wiki/U%C3%ADge_Provincehttp://en.wikipedia.org/wiki/Angolahttp://en.wikipedia.org/wiki/Epidemichttp://en.wikipedia.org/wiki/Mweka,_Democratic_Republic_of_the_Congohttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Plague_of_Athenshttp://en.wikipedia.org/wiki/Peloponnesian_Warhttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-10http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-10http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-10http://en.wikipedia.org/wiki/Lujo_virushttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-11http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-11http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-11http://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-11http://en.wikipedia.org/wiki/Lujo_virushttp://en.wikipedia.org/wiki/Viral_hemorrhagic_fever#cite_note-10http://en.wikipedia.org/wiki/Peloponnesian_Warhttp://en.wikipedia.org/wiki/Plague_of_Athenshttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Mweka,_Democratic_Republic_of_the_Congohttp://en.wikipedia.org/wiki/Epidemichttp://en.wikipedia.org/wiki/Angolahttp://en.wikipedia.org/wiki/U%C3%ADge_Provincehttp://en.wikipedia.org/wiki/Marburg_virushttp://en.wikipedia.org/wiki/Watsahttp://en.wikipedia.org/wiki/Durba,_Democratic_Republic_of_the_Congohttp://en.wikipedia.org/wiki/Democratic_Republic_of_the_Congohttp://en.wikipedia.org/wiki/Orientale_Provincehttp://en.wikipedia.org/wiki/Ebola_virushttp://en.wikipedia.org/wiki/Gabonhttp://en.wikipedia.org/wiki/M%C3%A9kambohttp://en.wikipedia.org/wiki/Yellow_Fever_Epidemic_of_1793

Documents

VIRAL haemorrhagic fevers .docx