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