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EBOLA VIRUS DISEASE (Contact) Please
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image and underlined links for details:[ [Also see: "Potential
Insect Vector Cycle"] According to the World Health
Organization Ebola Virus Disease
(EVD), formerly known as Ebola
Haemorrhagic Fever, is caused by an often-fatal virus in humans. The virus is transmitted to humans from wild animals and
spreads through human-to-human transmission. The average EVD case fatality rate is about 50%. Case
fatality rates have varied from 25% to 90% in outbreaks. The first EVD outbreaks
occurred in the remote villages of Central Africa, near rainforests. However, the latest outbreak in West
Africa has involved major urban as well as rural areas. Community commitment is
key to successfully controlling outbreaks. Outbreak control relies primarily
on case management, surveillance and contact tracing, a good laboratory
service, safe burials and social mobilization. Early supportive care
with rehydration and symptomatic treatment improves survival. There is as yet
no licensed treatment proven to neutralize the virus but a range of blood,
immunological and drug therapies are under development. There are currently no
licensed Ebola vaccines but
several potential candidates are undergoing evaluation. Studies of
insects found at Ebola outbreak
sites have failed to isolate Ebola in an arthropod. However, specimens were not collected at
the beginning of the outbreaks, and during the first Ebola Sudan outbreak, DDT was sprayed
around the hospital and the surrounding area. Kunz (1968)
reported Aedes aegypti as a vector of
the virus, but subsequent studies to ascertain whether Ebola replicates in A. aegypti have failed to
reproduce the result of the Kunz (1968) study. However, the recent study did not use the strains of Ebola, Ebola
Cote d'Ivoire, Ebola Sudan
and Ebola Zaire, that are the
causative agents of the outbreaks.
Only a small fraction of the specimens collected have been tested for Ebola.
Arthropods that were present at the beginning of outbreaks have yet to
be collected and analyzed. The
reservoir insect could be a seasonal insect, tick or mite and not be present
when insect species are collected for analysis. A particular
type arthropod could be an intermediate host and not the natural reservoir,
or another organism could be the intermediate host obtaining Ebola from a particular arthropod
species. = = = = = = = = = = = =
= = = = = = = = Key References: <medvet.ref.htm> <Hexapoda> Breman, Joel, et al.
1999. A Search for
Ebola Virus in Animals in the Democratic Republic of the Congo: Ecologic,
Virologic, and Serologic Surveys,
1979-1980. J. Infect. Diseases 179 (Suppl 1): S139-47. Conrad J. L. et al.
1978.
Epidemiological investigations of Marburg virus diseases, southern
Africa, 1975. Amer.
J. Tropical Med. & Hyg. 27:1210-5. Kunz, C. et al. 1968. Die vermehrung des Marburg-Virus in Aedes aegypt. Zentralbl Bakteriol I
Orig 208:347-9. Lolik, Pacifico.
1978. Containment and
Surveillance of the Ebola Virus Epidemic in Southern Sudan. Ebola Virus Haemorrhagic Fever. Berlin:
Elsevier/North-Holland Biomedical Press. Monath, Thomas.
1999. Ecology of Marburg and
Ebola Viruses: Speculations and Directions for Future Research. J. Infect. Diseases. 179
(Suppl 1):S127-38. Turrell M. J.
et al. 1996. Lack of virus replication in arthropods
after intrathoracic inoculation of Ebola Reston virus. Amer. J. Tropical Med.
& Hyg. 55:89-90. |