Ebola Zaire 1976 & 1995
To: virology@net.bio.net
From: roberts@thorin.uthscsa.edu (J.P. ROBERTS, MD)
Subject: Ebola Zaire 1976 & 1995
Date: 12 May 95 11:17:56 CST
The New York Times today reported a CDC report that the strain
of Ebola isolated in the current outbreak in Kikwit, Zaire is
very similar biochemically (immunologically?) to the strain
from the Zaire 1976 outbreak. A simultaneous outbreak in 1976
in neighboring Sudan was from a slightly different strain.
Detailed reports on both of these outbreaks were published in
The Bulletin of WHO in 1978; this is probably available iin
most university libraries.
Epidemiological investigation of the Sudan and Zaire 1976 outbreaks
revealed no evidence of airborne transmission. Transmission was
primarliy by the use of contaminated (pre-used) needles and
syringes or by close contact with bodily secretions. Casual
contact was not a risk for transmission. Ironically, what
halted the two outbreaks was closing the hospitals involved.
Standard infection control practices such as those routinely
used with HIV-infected patients in the US are sufficient to
prevent transmission. Unfortunately, such simple devices as
latex gloves, masks, and gowns are often unavailable in central
Africa.
-- End --
To: virology@net.bio.net
From: roberts@thorin.uthscsa.edu (J.P. ROBERTS, MD)
Subject: Ebola
Date: 14 May 95 04:33:11 CST
I've been reviewing virtually all of the peer-reviewed
publications about Ebola. After reading The Hot Zone, it's
clear that much of what is known about Ebola virus has
not been published in peer-reviewed press.
Here are some tidbits I haven't seen posted yet in this thread:
1976 Sudan 284 cases 53% mortality
1976 Zaire 318 cases 88% mortality
1979 Sudan "small" 65% mortality
1989 Reston, VA monkeys
1995 Zaire unknown unknown
1972,77,78 Zaire isolated cases
The 1989 Reston strain was similar to the 1976 Sudan strain.
(source: J.Clin.Path., 43:813).
The 1995 Zaire strain is similar to the 1976 Zaire strain.
(source: NY Times, 5-12-95)
The Reston strain infected four humans without causing illness.
The infection rate (how many of those who get virus
get the disease) is unknown but is probably around 75%.
Studies of rural central Africans have shown that
7-17% of them carry antibodies to Ebola. This strikes me
as a rather high rate for such an apparently virulent
disease. Nevertheless, it implies that some or even
many cases of Ebola infection are mild or even asymptomatic.
The best summary I have seen of the viral hemorrhagic fevers
is in Morbidity and Mortality Weekly Report, Feb 26, 1988.
MMWR should be in any university or municipal library.
Bear in mind that since Ebola's incubation period (the time
from infection until illness) is up to 15 days and there is no
rapid serologic test, it will be 2-3 weeks before we
can know whether the current outbreak is contained.
--- John P. Roberts, MD (roberts@uthscsa.edu)
San Antonio, Texas
"It bothers people when you are lucid and ironic." - A. Camus