X-Message-Number: 4448
Date: 25 May 95 04:52:01 EDT
From: Mike Darwin <>
Subject: Ebola outbreak summary <Forwarded Message>

Following is the final electronic text from the Morbidity
and Mortality Weekly Report (MMWR), vol. 44, no. 19, dated
May 19, 1995.  The MMWR is published by the U.S. Department
of Health and Human Services, Public Health Service, Centers
for Disease Control and Prevention (CDC), Atlanta, Georgia.

Outbreak of Ebola Viral Hemorrhagic Fever -- Zaire, 1995

     On May 6, 1995, CDC was notified by health authorities
and the U.S. Embassy in Zaire of an outbreak of viral
hemorrhagic fever (VHF)-like illness in Kikwit, Zaire (1995
population: 400,000), a city located 240 miles east of
Kinshasa. The World Health Organization and CDC were invited
by the Government of Zaire to participate in an
investigation of the outbreak. This report summarizes
preliminary findings from this ongoing investigation.
     On April 4, a hospital laboratory technician in Kikwit
had onset of fever and bloody diarrhea. On April 10 and 11,
he underwent surgery for a suspected perforated bowel.
Beginning April 14, medical personnel employed in the
hospital to which he had been admitted in Kikwit developed
similar symptoms. One of the ill persons was transferred to
a hospital in Mosango (75 miles west of Kikwit). On
approximately April 20, persons in Mosango who had provided
care for this patient had onset of similar symptoms.
     On May 9, blood samples from 14 acutely ill persons
arrived at CDC and were processed in the biosafety level 4
laboratory; analyses included testing for Ebola antigen and
Ebola antibody by enzyme-linked immunosorbent assay, and
reverse transcription-polymerase chain reaction (RT-PCR) for
viral RNA. Samples from all 14 persons were positive by at
least one of these tests; 11 were positive for Ebola
antigen, two were positive for antibodies, and 12 were
positive by RT-PCR. Further sequencing of the virus
glycoprotein gene revealed that the virus is closely related
to the Ebola virus isolated during an outbreak of VHF in
Zaire in 1976 (1).
     As of May 17, the investigation has identified 93
suspected cases of VHF in Zaire, of which 86 (92%) have been
fatal. Public health investigators are now actively seeking
cases and contacts in Kikwit and the surrounding area. In
addition, active surveillance for possible cases of VHF has
been implemented at 13 clinics in Kikwit and 15 remote sites
within a 150-mile radius of Kikwit. Educational and
quarantine measures have been implemented to prevent further
spread of disease.

Reported by: M Musong, MD, Minister of Health, Kinshasa, T
Muyembe, MD, Univ of Kinshasa; Dr. Kibasa, MD, Kikwit
General Hospital, Kikwit, Zaire. World Health Organization,
Geneva. Div of Viral and Rickettsial Diseases, and Div of
Quarantine, National Center for Infectious Diseases;
International Health Program Office, CDC.

Editorial Note: Ebola virus and Marburg virus are the two
known members of the filovirus family. Ebola viruses were
first isolated from humans during concurrent outbreaks of
VHF in northern Zaire (1) and southern Sudan (2) in 1976. An
earlier outbreak of VHF caused by Marburg virus occurred in
Marburg, Germany, in 1967 when laboratory workers were
exposed to infected tissue from monkeys imported from Uganda
(3). Two subtypes of Ebola virus--Ebola-Sudan and
Ebola-Zaire--previously have been associated with disease in
humans (4). In 1994, a single case of infection from a newly
described Ebola virus occurred in a person in Cote d'Ivoire.
In 1989, an outbreak among monkeys imported into the United
States from the Philippines was caused by another Ebola
virus (5) but was not associated with human disease.
     Initial clinical manifestations of Ebola hemorrhagic
fever include fever, headache, chills, myalgia, and malaise;
subsequent manifestations include severe abdominal pain,
vomiting, and diarrhea. Maculopapular rash may occur in some
patients within 5-7 days of onset. Hemorrhagic
manifestations with presumptive disseminated intravascular
coagulation usually occur in fatal cases. In reported
outbreaks, 50%-90% of cases have been fatal (1-3,6).
     The natural reservoirs for these viruses are not known.
Although nonhuman primates were involved in the 1967 Marburg
outbreak, the 1989 U.S. outbreak, and the 1994 Cote d'Ivoire
case, their role as virus reservoirs is unknown.
Transmission of the virus to secondary cases occurs through
close personal contact with infectious blood or other body
fluids or tissue. In previous outbreaks, secondary cases
occurred among persons who provided medical care for
patients; secondary cases also occurred among patients
exposed to reused needles (2). Although aerosol spread has
not been documented among humans, this mode of transmission
has been demonstrated among nonhuman primates. Based on this
information, the high fatality rate, and lack of specific
treatment or a vaccine, work with this virus in the
laboratory setting requires biosafety level 4 containment
     CDC has established a hotline for public inquiries
about Ebola virus infection and prevention ([800] 900-0681).
CDC and the State Department have issued travel advisories
for persons considering travel to Zaire. Information about
travel advisories to Zaire and for air passengers returning
from Zaire can be obtained from the CDC International
Travelers' Hotline, (404) 332-4559.

1. World Health Organization. Ebola haemorrhagic fever in
Zaire, 1976: report of an international commission. Bull WHO
2. Baron RC, McCormick JB, Zubeir OA. Ebola virus disease in
southern Sudan: hospital dissemination and intrafamilial
spread. Bull World Health Organ 1981;61:997-1003.
3. Peters CJ, Sanchez A, Rollin PE, Ksiazek TG, Murphy FA.
Filoviridae: Marburg and Ebola viruses. In: Fields BN, Knipe
DM, Howley PM, eds. Field's virology. 3rd ed. New York:
Raven Press, Ltd, 1996 (in press).
4. McCormick JB, Bauer SP, Elliott LH, Webb PA, Johnson KM.
Biologic differences between strains of Ebola virus from
Zaire and Sudan. J Infect Dis 1983;147:264-7.
5. Jarling PB, Geisbert TW, Dalgard DW, et al. Preliminary
report: isolation of Ebola virus from monkeys imported to
USA. Lancet 1990;335:502-5.
6. CDC. Management of patients with suspected viral
hemorrhagic fever. MMWR 1988;37(no. S-3).
7. Peters CJ, Sanchez A, Feldmann H, Rollin PE, Nichol S,
Ksiazek TG. Filoviruses as emerging pathogens. Seminars in
Virology 1994;5:147-54.

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