Hi there folks,
These tidbits are targeted towards "armchair" virologists. They
are just for those seeking a little information about this thing for
curiosity.
The Ebola virus belongs to one of the 13 families of RNA
viruses, the FILOVIRUSES, along with Marburg virus. Previously these two
(Ebola and Marburg) were grouped under the RHABDOVIRUSES.
(the thirteen type of RNA viruses and examples of each are as follows:
PARAMYOVIRIDAE - measles,mumps,parainfluenza,Sendai
ORTHOMYXOVIRIDAE - influenza A,B & C
CORONAVIRIDAE - coronavirus
ARENAVIRIDAE - lymphocytic choriomeningitis,Lassa
fever,Tacaribe virus complex
RHABDOVIRIDAE - rabies
FILOVIRIDAE - Marburg,Ebola
BUNYAVIRIDAE - California encephalitis,sandfly fever,Crimean
Congo hemorrhagic fever
RETROVIRIDAE - human T cell leukemia I & II,human
immunodeficiency viruses I & II
REOVIRIDAE - rotavirus,reovirus,Californa tick fever
PICORNAVIRIDAE - rhinovirus,poliovirus,ECHO
virus,coxsackievirus,hepatitis A virus
TOGAVIRIDAE - rubella,Western Eastern and Venezuelan equine
encephalitis,Sindbis,Semlike forest
FLAVIVIRIDAE - yellow fever,dengue,St. Louis encephalitis
CALICIVIRIDAE - Norwalk agent
)
Filoviruses are filamentous, enveloped, negative-strand, single
stranded RNA viruses.
The virus replicates in the cytoplasm of the infected cell.
Microscopic analysis of infected cells show eosinophilic
cytoplasmic inclusions. Large amounts of viruses are replicated in the
host cell causing necrosis of the liver, spleen, lymph nodes and lungs.
The virus causes severe hemorrhaging leading to edema,
hypovolemic shock, and, possibly death.
Marburg virus was discovered in Marburg, Germany when laboratory
workers were infected by African green monkeys.
Marburg virus infections have been reported in Zimbabwe and
Kenya.
Ebola virus was disovered in Zaire (giving name to one strain of
Ebola- Ebola Zaire virus)
Mechanisms of natural transmisson are unknown, but viruses have
been known to be transmitted by accidental transmission accidental
injections and contaminated syringes. Contact with body fluids may also
cause infection.
Symptoms of infection include:
headache and myalgias
nausea, vomiting, diarrhea
hemorrhaging from multiple sites
Death occurs in 90% of those infected within 10 days.
Handling of these viruses requires level 4 isolation (very
stringent)
Both viruses can be grown in tissue cultures (Ebola requires
animal innoculation because it causes death to the tissue culture).
Viral antigens can be detected by direct immunofluorescence
analysis.
IgG and IgM antibodies to filovirus can be detected by indirect
fluorescence antibody, enzyme linked immunosorbent assay or radioimmuno
assay.
Infected individuals should be quarantined and contaminated
animals should be sacrificed.
The Ebola Zaire virus is deadly, no doubt about it. It has already shown
itself to mutate into several varieties (luckily, some non-pathogenic to
humans), but it can mutate into worse forms (picture an air-borne
virus). This is definetly something to watch out for as Marburg and
Ebola are not the only viruses waiting to be unleashed into the human
populace.
I hope these tidbits are enlightening into the world of filioviruses. I
recommend reading such books as "Textbook of Human Virology, 2nd
edition" by RB Belshe, Mosby publications St. Louis for detailed
information. Good luck to all.
Alexander Madama
New York College of Osteopathic Medicine
(BTW: lots of the info I used comes from "Medical Microbiology", PR
Murray et al., Mosby publications and thanks to Dr. Larry Green here at
NYCOM for his wonderful talks on virology)
