First-ever Marburg virus disease outbreak in Equatorial Guinea
and Tanzania: an imminent crisis in West and East Africa.
Abstract
The Marburg virus, which is a member of the same virus family as the
Ebola virus called Filoviridae, causes the severe infectious disease
known as Marburg Virus Disease (MVD). Previously, different outbreaks of
MVD have appeared in different African countries, including Ghana,
Guinea, Uganda, Angola, the Democratic Republic of the Congo, Kenya, and
South Africa. For the first time, Equatorial Guinea and Tanzania are
experiencing MVD outbreaks. A total of 15 laboratory-confirmed cases of
MVD and 23 probable cases have been reported in Equatorial Guinea since
the confirmation of the outbreak on 13 February 2023. The first MVD
outbreak in the United Republic of Tanzania was formally confirmed by
the Ministry of Health on March 21, 2023. As of 22 March, there were
eight cases and five fatalities (case fatality ratio [CFR]: 62.5%).
Due to the facts that Ebebiyin and Nsock Nsomo districts, the affected
regions of Equatorial Guinea, borders Cameroon and Gabon, and Kagera
region, the affected region of Tanzania, borders Uganda, Rwanda and
Burundi, there is fear of cross-border spread of MVD due to cross-border
migrations, and this can be a great crisis in West and East Africa.
Although there are currently outbreaks of MVD in Equatorial Guinea and
Tanzania, there is currently no proof of an epidemiological connection
between the two outbreaks. The aim of this paper is to describe Marburg
Virus Disease (MVD), describe its first outbreak in Equatorial Guinea
and Tanzania, explain the efforts being used and the challenges being
faced in MVD mitigation, and recommend different measures to be taken to
cope with the outbreak of MVD in Equatorial Guinea and Tanzania.
Keywords: Marburg virus disease, outbreak, Equatorial Guinea, Tanzania
Introduction
A severe infectious disease called Marburg Virus Disease (MVD) is caused
by the Marburg virus, a member of the Filoviridae family of viruses that
also includes the Ebola virus [1]. Haemorrhagic fever outbreaks in
laboratories in Marburg and Frankfurt (in Germany), and Belgrade (in
Yugoslavia [Serbia of today]), led to the discovery of the Marburg
virus in 1967 [2]. Two viruses, MARV and Ravn, are members of the
Marburgvirus genus. The World Health Organization has identified MARV as
being of the utmost priority. The virus has a case fatality rate that
ranges from 24.0 to 88.0%, showing that it is deadly and that extensive
knowledge on it is required [3]. MARV is a single-stranded negative
sense RNA virus that is enveloped. It is morphologically similar to silk
and has a length that ranges from 800 to 14,000 nm. When it is 790 nm in
length, it is most contagious. Seven structural proteins make up MARV.
Although having a structure that is remarkably comparable to the Ebola
virus, the MARV may cause distinct antibodies in susceptible
individuals. MARV is thought to have been the first human-discovered
filovirus [4].
The Egyptian fruit bat (Rousettus aegyptiacus ) serves as the
reservoir of the zoonotic virus [5], [6]. Previous research
demonstrates that most of the primary infections associated with natural
outbreaks of MARV disease to date have been related to human access to
caves, for example, cave visitors and mine workers [3]. Following
the first human-to-human transmission of a zoonotic disease caused by an
infected animal, the disease is subsequently spread more widely via
close human-to-human contact. This can happen either directly or by
coming into contact with contaminated fomites or bodily fluids [3].
The transmission of Marburg can also occur during burial ceremonies that
involve getting into close contact with the corpse of the deceased
[7].
The incubation period of the Marburg virus lasts 3–21 days (usually
between 5 and 10 days) and is probably influenced by the infectious dose
and route [8]. After the incubation period, people often have sudden
illnesses with vague symptoms such as fever, chills, headache,
odynophagia, myalgia, vomiting, and diarrhea. Early cases can be
overlooked because they resemble more widespread infections such as
malaria, typhoid, or rickettsial diseases. Early signs of MVD frequently
include rash, which is characterized as non-pruritic, erythematous, and
maculopapular. It starts out focally before becoming confluent and
widespread. During the initial outbreak, the condition starts as a
distinctly marked, pin-sized red papule around the hair roots at the
buttocks, trunk, and outside of both upper arms between the fifth and
seventh day. This papule lasts up to 24 hours before developing into a
maculopapular rash, which later coalesce [9].
Since MVD was discovered, there have been two sizable outbreaks that
occurred simultaneously, one of which was linked to laboratory research
involving African green monkeys that were imported from Uganda. Two
unconnected sporadic occurrences of the disease occurred in 2008 in
tourists from the Netherlands and the United States while they were
visiting a cave in Uganda that was home to a sizable colony of Rousettus
bats. Previous reports of MVD outbreaks include Ghana (2022), Guinea
(2021), Uganda (2017, 2014, 2012, 2007), Angola (2004–2005), the
Democratic Republic of the Congo (1998 and 2000), Kenya (1990, 1987,
1980), and South Africa (1975) [10]. The greatest MVD outbreak to
date was in Angola in 2005, where 374 cases and 329 deaths were
reported, with an 88% CFR. There have been four previous epidemics in
Uganda, with case fatality rates ranging from 27 to 100% in 2007, 2012,
2014, and 2017 [11]. Table 1 shows the history of Marburg Virus
Disease outbreaks from 1967 to 2022. Countries reporting outbreaks of
MVD until 2023 are shown in Figure 1.
Table 1. History of Marburg Virus Disease Outbreaks from 1967 to 2022