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All you need to know about Marburg haemorrhagic fever
Datelinehealth-Africa News
2005-05-03
Marburg haemorrhagic fever is a rare though severe and highly fatal disease.
The disease and what causes it
Marburg haemorrhagic fever is a rare though severe and highly fatal
disease. It is called Haemorrhagic fever because unlike many other fever
causing diseases, Marburg haemorrhagic fever is often associated with
significant bleeding from multiple sites in the body during days 5 to 7 of
the onset of the illness. The disease is caused by a Ribonucleic Acid
(RNA) virus of the filovirus family (Marburg virus). This virus is
from the same family as the one that causes Ebola
haemorrhagic fever.
Filoviruses are among the most virulent pathogens known to infect
humans.
Natural reservoir of the disease causing virus
Despite years of intensive investigation involving the testing of hundreds
of animals, insects, and plants, no proven animal reservoir or other
environmental source of the causative virus has been identified. Bats have
been alleged to be reservoirs, but there are no hard evidence to support
this. Monkeys are susceptible to infection but are not considered viable
reservoir hosts as virtually all infected animals die too rapidly to
sustain survival of the virus. Humans are not considered part of the
natural transmission cycle their infection is accidental.
Transmission
Transmission of the virus from person to person requires extremely close
contact with a patient. Infection results from contact with blood or other
body fluids (faeces, vomitus, urine, saliva, and respiratory secretions)
with high virus concentration, especially when these fluids contain blood.
Transmission via infected semen can occur up to seven weeks after clinical
recovery. Infection through casual contact is thought to be exceedingly
rare. The low rate of transmission to persons with casual contact suggests
that air borne transmission via the respiratory tract is not efficient, if
it occurs at all. Transmission does not occur during the incubation
period. Patients appear to be most infectious during the period of severe
illness accompanied by haemorrhagic manifestations. Close contact with a
severely ill patient, during care at home or in hospital, and certain
burial practices are common routes of infection. Transmission via
contaminated injection equipment or through needle-stick injuries is
associated with more severe disease, rapid deterioration, and possibly
higher death rate.
Reported outbreaks
The first reported outbreaks of this disease occurred in Marburg, Germany
and in Belgrade, the former Yugoslavia in 1967. These outbreaks were
linked to laboratory workers using African green monkeys (Cercopithecus
aethiops) imported from Uganda. Isolated occurrences of the disease in
humans were reported in South Africa (in 1975) and, Kenya (in 1980 and
1987). An outbreak in the Democratic Republic of the Congo, (DRC),
(formerly Zaire) marked the first large outbreak of this disease under
natural conditions. The outbreak occurred from late 1998 to 2000. It
involved 154 cases, of which 128 were fatal, representing a case fatality
of 83%. The majority of cases in the DRC outbreak occurred in young male
workers at a gold mine in Durba, in the north-eastern part of the country.
This region proved to be the major area (epicentre) of the outbreak. Cases
were subsequently detected in a neighbouring village called Watsa. Family
members involved in the close care of patients accounted for some cases,
but secondary transmission appeared to be rare.
A more recent and ongoing outbreak has been reported in Angola.
The outbreak is believed to have begun in October 2004 in Uige Province, a
region that is located in north-western Angola (view
map & details). As of 27 April 2005, the Angolan Ministry
of Health reported a cumulative total of 275 cases, of which 255 were
fatal. A case fatality of 93 percent. Most cases detected in other
provinces have been linked directly to the outbreak in Uige.
Incubation period
The disease, has an incubation period of 3 9 days. Incubation period
refers to the time between contact with the causative agent and the first
noticeable appearance of disease related symptoms.
Clinical features
Haemorrhagic fever illness caused by Marburg virus begins abruptly, with
severe headache and malaise (weakness and poor health), muscle aches and
pains. A high fever usually appears on the first day of illness, followed
by progressive and rapid deterioration in health. A severe watery
diarrhoea, abdominal pain and cramping, nausea, and vomiting begin about
the third day. Diarrhoea can persist for a week. The appearance of
patients at the early period of the disease has been described as showing
ghost-like drawn features, deep-set eyes, expressionless faces, and
extreme weakness coupled with lack of interest (lethargy). A non-itchy
rash appearing between days 2 and 7 after symptom onset could be a feature
in most patients.
Many patients develop severe bleeding (haemorrhagic) manifestations
between days 5 and 7. Fatal cases usually have some form of bleeding,
often from multiple sites. Findings of fresh blood in vomitus and faeces
are often accompanied by bleeding from the nose, gums, and vagina.
Spontaneous bleeding at venipuncture sites can be particularly
troublesome. During the severe phase of illness, patients have sustained
high fevers and involvement of the brain can result in confusion,
irritability, and aggression. Infection and tenderness in the testis (orchitis)
has been reported occasionally in the late phase of disease (day 15). In
fatal cases, death occurs most often between 8 and 9 days after symptom
onset, usually preceded by severe blood loss and shock.
Diagnosis, Treatment and Public health control
Marburg haemorrhagic fever may be difficult to diagnose early since many
of its initial symptoms are mimicked by other tropical infectious diseases
including the common malaria. A high level of suspicion is required,
especially if the presenting patient has a history of travel or close
contact with an ill individual who has travelled or lived in regions where
the disease is known to occur. There are no known preventive or curative
vaccine or specific treatment for the disease. Acute care is often
directed at managing the severe presenting symptoms ans stabilizing the
patient body systems generally. Care is best provided in strictly enforced
isolation unit with excellent attention to barrier nursing, hygiene and
body fluid waste disposal.
Survival from the disease is not unknown where care is provided early.
Public health control of an outbreak of Marburg haemorrhagic fever can be
very challenging as the disease commonly occurs in resource-poor regions
of the world, like Angola, Uganda and DRC in Africa. Early mobilization of
infectious disease control personnel to the outbreak region is mandatory.
These personnel may be local health ministry officials and/or from expert
institutions like the WHO.
Detailed and prompt surveillance system has to be put in place to identify
affected individuals, isolate and treat them as early as possible.
Appropriate community sensitization, education and mass mobilization for
healthy behaviours and practices need to be emphasized in affected
populations. Adequate provision of supplies for acute care, barrier
nursing, proper disposal of corpses and body fluids of infected patients
are essential for containment of the disease. These and other
population-directed (public) health measures help to bring outbreaks under
control.
(Source: Dateline health-Africa News, May 1, 2005)
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