Viral hemorrhagic fever: Difference between revisions
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'''Viral hemorrhagic fevers (VHFs)'' are a group of diseases that share the ability to damage multiple organ systems, among them the vascular system of blood vessels. Vascular damage, and in some cases damage to clotting mechanism, cause frequent bleeding, thus the general term '''hemorrhagic fever (HF)'''. While there are some common biological features among the causative viruses, the group is characterized more by the nature of the disease presentation than the classification of the [[pathogen]]. | '''Viral hemorrhagic fevers (VHFs)''' are a group of diseases that share the ability to damage multiple organ systems, among them the vascular system of blood vessels. Vascular damage, and in some cases damage to clotting mechanism, cause frequent bleeding, thus the general term '''hemorrhagic fever (HF)'''. While there are some common biological features among the causative viruses, the group is characterized more by the nature of the disease presentation than the classification of the [[pathogen]].<ref name=CIDRAP>{{citation | ||
| title = Viral Hemorrhagic Fever (VHF): Current, comprehensive information on pathogenesis, microbiology, epidemiology, diagnosis, treatment, and prophylaxis | |||
| author = Center for Infectious Disease Research & Policy | |||
| publisher = Academic Health Center -- University of Minnesota | |||
| year = 2008 | |||
| url = http://www.cidrap.umn.edu/cidrap/content/bt/vhf/biofacts/vhffactsheet.html}}</ref> | |||
Not all fevers accompanied by bleeding are VHF, although until a VHF is excluded, the potential public health risk requires assuming that the cause is the most contagious and dangerous form consistent with the presentation. For example, [[scrub typhus]], caused by the [[bacterium]] ''[[Orientia tsutsugamushi]], can present as a HF. | Not all fevers accompanied by bleeding are VHF, although until a VHF is excluded, the potential public health risk requires assuming that the cause is the most contagious and dangerous form consistent with the presentation. For example, [[scrub typhus]], caused by the [[bacterium]] ''[[Orientia tsutsugamushi]], can present as a HF. | ||
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==Characteristics of the viruses== | ==Characteristics of the viruses== | ||
Several different families of virus cause VHFs. They share the property of being RNA viruses with a lipid (fatty) coat. | Several different families of virus cause VHFs. They share the property of being RNA viruses with a [[lipid]] (fatty) coat. | ||
While the focus of this article is VHF, the list below shows that not all species of the families cause HF; some species can present as a non-HF (e.g., dengue) or HF (e.g., dengue HF). The recognized familes are: | While the focus of this article is VHF, the list below shows that not all species of the families cause HF; some species can present as a non-HF (e.g., dengue) or HF (e.g., dengue HF). The recognized familes are: | ||
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**non-HF: none identified | **non-HF: none identified | ||
*[[flavirus]]es (genus ''flavivirus'', family ''[[Flaviviridae]]'') | *[[flavirus]]es (genus ''flavivirus'', family ''[[Flaviviridae]]'') | ||
**HF: Dengue HF, Omsk HF | **HF: Dengue HF, Omsk HF, Yellow fever (hemorrhagic) | ||
**non-HF: Dengue fever, Central European tick-borne encephalitis, Far Eastern tick-borne encephalitis, Kyasanur Forest disease, Hepatitis C, West Nile virus, Yellow Fever Virus | **non-HF: Dengue fever, Central European tick-borne encephalitis, Far Eastern tick-borne encephalitis, Kyasanur Forest disease, Hepatitis C, West Nile virus, Yellow Fever Virus | ||
==Epidemiology== | ==Epidemiology== | ||
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When the reservoir is known, extermination, sanitation and barriers are important. | When the reservoir is known, extermination, sanitation and barriers are important. | ||
While a [[yellow fever]] vaccine has long been available, other accine development recently has accelerated.<ref name=CIDRAP /> There has been some success with Argentine HF, also known as Junin, It may also be effective against Bolivian/Machupo.<ref name=>{{citation | |||
| authors= Maiztegui JI, McKee KT, Barrera Oro JG, ''et al.'' | |||
| title = Protective efficacy for a live attenuated vaccine against Argentine hemorrhagic fever. | |||
| journal = J Infect Dis | |||
| date = 1998 Feb | |||
| volume = 177 | |||
| pages = 277-83 | |||
| url = http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=9466512&query_hl=122&itool=pubmed_docsum}}</ref> | |||
Research trials have been published on vaccines for Ebola and Marburg. <ref name=CIDRAP /> | |||
==Treatment== | ==Treatment== | ||
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Given that a number of these diseases occur in underdeveloped countries where full barrier precautions may not be possible, the World Health Organization (WHO), with the CDC, has prepared a guide, focused on Africa, for what can be done with limited resources.<ref name=VHF-Africa>{{citation | Given that a number of these diseases occur in underdeveloped countries where full barrier precautions may not be possible, the World Health Organization (WHO), with the CDC, has prepared a guide, focused on Africa, for what can be done with limited resources.<ref name=VHF-Africa>{{citation | ||
| title = Infection Control for Viral Haemorrhagic Fevers In the African Health Care Setting | | title = Infection Control for Viral Haemorrhagic Fevers In the African Health Care Setting | ||
| author = Centers for Disease Control & World Health Organization | |||
| url = http://www.cdc.gov/ncidod/dvrd/spb/mnpages/vhfmanual.htm}}</ref> | | url = http://www.cdc.gov/ncidod/dvrd/spb/mnpages/vhfmanual.htm}}</ref> | ||
==References== | ==References== | ||
{{reflist}} | {{reflist}} | ||
Revision as of 20:33, 30 May 2008
Viral hemorrhagic fevers (VHFs) are a group of diseases that share the ability to damage multiple organ systems, among them the vascular system of blood vessels. Vascular damage, and in some cases damage to clotting mechanism, cause frequent bleeding, thus the general term hemorrhagic fever (HF). While there are some common biological features among the causative viruses, the group is characterized more by the nature of the disease presentation than the classification of the pathogen.[1]
Not all fevers accompanied by bleeding are VHF, although until a VHF is excluded, the potential public health risk requires assuming that the cause is the most contagious and dangerous form consistent with the presentation. For example, scrub typhus, caused by the bacterium Orientia tsutsugamushi, can present as a HF.
Characteristics of the viruses
Several different families of virus cause VHFs. They share the property of being RNA viruses with a lipid (fatty) coat.
While the focus of this article is VHF, the list below shows that not all species of the families cause HF; some species can present as a non-HF (e.g., dengue) or HF (e.g., dengue HF). The recognized familes are:
- arenaviruses (genus arenavirus, family Arenaviridae)
- HF: Argentine/Junin, Bolivian/Machupo, Flexal, Lassa, Guanarito, Sabia, Venezuelan
- non-HF: Flexal virus, Lymphocytic choriomeningitis virus
- bunyaviruses (genus bunyavirus, family Bunyaviridae
- HF: Crimean-Congo, hemorrhagic fever with renal syndrome (HFRS)
- non-HF: Hantavirus pulmonary syndrome (HPS), Rift Valley fever (RVF)
- filoviruses (genus filovirus, family Filoviridae)
- flaviruses (genus flavivirus, family Flaviviridae)
- HF: Dengue HF, Omsk HF, Yellow fever (hemorrhagic)
- non-HF: Dengue fever, Central European tick-borne encephalitis, Far Eastern tick-borne encephalitis, Kyasanur Forest disease, Hepatitis C, West Nile virus, Yellow Fever Virus
Epidemiology
At the species level, they are limited to a geographic level, and on an animal reservoir. Some can transmit from human to human as well as from animal to human. Not all reservoirs have been identified.
Outbreaks in humans are unpredictable.
While none is definitely known to have been weaponized, some VHFs do have potential as biological weapons. [2]
Prevention
When the reservoir is known, extermination, sanitation and barriers are important.
While a yellow fever vaccine has long been available, other accine development recently has accelerated.[1] There has been some success with Argentine HF, also known as Junin, It may also be effective against Bolivian/Machupo.[3]
Research trials have been published on vaccines for Ebola and Marburg. [1]
Treatment
For most of the VHF, the treatment is supportive, with barrier precautions to avoid spread. Ribavirin is helpful for Lassa fever. Plasma from recovering patients has helped some patients with Argentine hemorrhagic fever.
Given that a number of these diseases occur in underdeveloped countries where full barrier precautions may not be possible, the World Health Organization (WHO), with the CDC, has prepared a guide, focused on Africa, for what can be done with limited resources.[4]
References
- ↑ 1.0 1.1 1.2 Center for Infectious Disease Research & Policy (2008), Viral Hemorrhagic Fever (VHF): Current, comprehensive information on pathogenesis, microbiology, epidemiology, diagnosis, treatment, and prophylaxis, Academic Health Center -- University of Minnesota
- ↑ Borio L. et al. for the Working Group on Civilian Biodefense (May 8, 2002), "Consensus Statement: Viral Hemorrhagic Fevers as Biological Weapons", Journal of the American Medical Association (no. 18): 2391-2405
- ↑ Maiztegui JI, McKee KT, Barrera Oro JG, et al. (1998 Feb), "Protective efficacy for a live attenuated vaccine against Argentine hemorrhagic fever.", J Infect Dis 177: 277-83
- ↑ Centers for Disease Control & World Health Organization, Infection Control for Viral Haemorrhagic Fevers In the African Health Care Setting