Figure 1. Countries reporting outbreaks of Marburg virus disease.
Source: Centers for Disease Control and Prevention, National Center for
Emerging and Zoonotic Infectious Diseases (NCEZID), Division of
High-Consequence Pathogens and Pathology (DHCPP), Viral Special
Pathogens Branch (VSPB).
For the first time, Equatorial Guinea is facing Marburg virus disease
outbreak. The Ministry of Health and Social Welfare of Equatorial Guinea
reported the first case on February 7, 2023 [7]. This is the same
case in Tanzania: the country is experiencing the first outbreak of the
Marburg virus disease. The Marburg virus disease (MVD) outbreak in the
United Republic of Tanzania was declared on March 21, 2023, by the
Ministry of Health (MoH) of that nation [10]. 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 [10].
Outbreak and epidemiology of Marburg virus disease in
Equatorial Guinea
In two villages in the district of Nsock Nsomo, eastern province of
Kie-Ntem, Río Muni Region, the Ministry of Health and Social Welfare of
Equatorial Guinea reported at least eight deaths that occurred between 7
January and 7 February 2023. The cases, according to the current
epidemiological study, began with fever that preceded weakness,
vomiting, and blood-stained diarrhea. In two cases, skin lesions and
otorrhagia also appeared. Eight blood samples from contacts were taken
on 9 February 2023, and sent to the Centre Interdisciplinaire de
Recherches Médicales de Franceville (CIRMF) in Gabon, where real-time
polymerase chain reaction (RT-PCR) testing revealed that they were free
of Marburg and Ebola viruses [7].
On 12 February 2023, eight more blood samples were obtained from
different contacts and delivered to the Institute Pasteur in Dakar,
Senegal. One of these samples came from a suspected case that was RT-PCR
verified to have the Marburg virus. The patient had a fever, non-bloody
vomiting, bloody diarrhea, and convulsions. On February 10, 2023, the
patient passed away at the Ebebiyin District Hospital. Epidemiological
evidence connected the case with four other persons of deceased cases
from one of the communities in the Nsoc-Nsomo district [7].
By using RT-PCR at a mobile lab at the Regional Hospital of Ebibeyin on
13 March 2023, samples from two more people from the Kié-Ntem province
tested positively for MVD. On 15 March 2023, a sample from a person
living in Litoral province who was epidemiologically connected to a case
that had been confirmed in Kié-Ntem was positive for MVD after being
subjected to RT-PCR by the same laboratory. The two provinces (Kié-Ntem
and Litoral) are separated by around 150 kilometers and are situated in
different regions of the nation. Three other laboratory confirmed
positive cases from the Litoral province were reported on March 18 and
20. Two further laboratory-verified cases from the province of Centre
Sur were reported on March 20. Since then, six additional cases have
been reported. The possibility of unnoticed spread of the virus in the
community is suggested by the wide geographic distribution of the cases
and the hazy epidemiological connections in the Centre Sur province.
Since the outbreak began, a total of 15 laboratory-confirmed cases of
MVD and 23 probable cases have been reported. Laboratory-confirmed cases
were found to have 11 fatalities (Case Fatality Ratio (CFR) among
confirmed cases: 78.6%); all probable cases also had fatal outcomes;
one confirmed case had an undetermined result. Healthcare professionals
reported four laboratory-confirmed cases (26.6%), including two fatal
instances. Three of the confirmed patients have recovered. [12],
[13].
Outbreak and epidemiology of Marburg virus disease in
Tanzania
On March 16, 2023, the Ministry of Health of the United Republic of
Tanzania declared that two villages in Bukoba district, Kagera region,
northern Tanzania, had seven cases and five fatalities associated with
an unidentified disease. Subsequently, the Tanzanian National Public
Health Laboratory used reverse transcriptase-polymerase chain reaction
(RT-PCR) to confirm the cases as Marburg virus infection. The first MVD
outbreak in the nation was officially confirmed by the Ministry of
Health on 21 March 2023. As of 22 March, the Kagera region had eight
cases, including five fatalities (case fatality ratio [CFR]:
62.5%). Treatment is still being provided to the three remaining
patients. No cases have been documented outside the Bukoba district as
of March 22 [10].
The first case of MVD was identified in a person with a travel history
on Goziba Island in Lake Victoria in Tanzania and symptoms were
developed after the traveler returned to his village of Bukoba. The
patient died in the community. Four further cases from the same family
as this index case were detected. Also, among the healthcare workers who
treated them, there were two cases reported, one of which resulted in
death. The eighth case is still under investigation, so no information
is available. Fever, diarrhea, vomiting, numerous bleeds, and kidney
failure were the patients’ reported symptoms. The National Public Health
Laboratory tested samples from both dead and living cases and confirmed
the Marburg virus [10].
Efforts and challenges to mitigate Marburg virus disease in
Equatorial Guinea and Tanzania
Different public health responses are being implemented in Equatorial
Guinea and Tanzania, but there are also different challenges. Within
Equatorial Guinea, to identify the cause of the outbreak, comprehensive
epidemiological investigations are being conducted. National teams have
been sent to affected districts with the purpose of locating and
isolating cases and contacts, and treating patients. The WHO has also
sent out specialists in epidemiology, case management, infection
control, laboratory, and risk communication to aid national response
operations and guarantee community participation. Also, 500 health
professionals will get a viral hemorrhagic fever kit from WHO that
includes personal protective equipment in addition to tents, tools for
sample collection and analysis. As efforts are being made to establish
laboratory facilities locally, WHO is providing support for the
transportation of samples to labs in Senegal and Gabon [12].
Regional and district-level rapid response teams have been sent to
Tanzania to conduct investigations and implement response plan. Contact
tracking initiatives have also been implemented to keep an eye on others
who exhibit comparable symptoms in the local population and medical
facilities, including contacts with known patients. On March 21, health
workers followed up and monitored 140 of the 161 contacts that had been
discovered. In the Kagera region, risk communication initiatives have
also been launched to spread messages about health awareness, education,
and prevention [10].
Although different measures have been taken against the spread of the
Marburg virus in both Equatorial Guinea and Tanzania, there is still
fear of cross-border spread of the virus. For instance, in the
Equatorial Guinean districts of Ebebiyin and Nsock Nsomo, Cameroon, and
Gabon, there are many cross-border people migrations and relatively
porous boundaries. This represents a risk of cross-border spread of the
virus [12]. The affected area of Tanzania, Kagera region, borders
three nations (Uganda to the north, Rwanda and Burundi to the west), as
well as Lake Victoria, and cross-border population movements could
increase the risk of disease transmission. In addition, the fruit bat
species (Roussettus aegyptiacus) has been identified in other
nearby nations that neighbor the affected Kagera region; as a result,
these countries may be attached by MVD as they are home to the same bat
species that carry the virus [10]. The risk of spreading MVD in
Tanzania at the national level is rated very high due to the high CFR
and existing risk of the outbreak spreading to other regions of the
country, the insufficient human, financial, and material resources to
implement response interventions, and the likelihood that existing
capacities will be overwhelmed if cases increase [10].
It is difficult to diagnose Marburg virus disease. Because many other
tropical febrile illnesses have some clinical symptoms of MVD in its
early stages, it can be challenging to make a clinical diagnosis of the
condition. Ebola virus disease, malaria, typhoid fever, leptospirosis,
rickettsial diseases, and plague are a few diseases that must be ruled
out [12]. This difficulty in the diagnosis of MVD can delay the
identification and treatment of a disease, the factor that can increase
its mortality rate and the transmission rate.
Except rehydration with oral or intravenous fluids and treatment of
specific symptoms that improve survival, no current vaccines or
antiviral medications are approved to cure MVD, despite the fact that a
variety of potential treatments, including blood products, immune, and
drug therapies, are being evaluated [12]. The Marburg virus (MARV)
outbreak in Guinea and Ghana led to the formation of the ”MARVAC”
consortium, which is made up of experts in the field of vaccine research
and development. The consortium’s goal is to assist in a quick response
to the threat posed by this infectious disease. Soon after the virus was
identified, work on a MARV vaccine began with only little progress.
Several different vaccine platforms for MARV have been tested in rodent
models, but only some of these candidate vaccines showed protective
efficacy in nonhuman primates (NHPs). However, Currently, there are no
MARV vaccines or treatments that have received regulatory agency
approval [14].
Recommendations
Controlling the Marburg virus disease outbreak requires a variety of
interventions, including social mobilization, case management,
surveillance, including contact tracking, good laboratory service, and
infection prevention and control, including safe and dignified burials
[12]. In all impacted health zones, surveillance and detection
efforts—including contact tracing and active case finding—should be
stepped up. Identifying those who may have come into contact with
someone who has the Marburg virus and tracking their health for 21 days
are among the measures to be taken to control MVD outbreaks. Other
measures include separating healthy and ill people to stop further
transmission, caring for confirmed patients, maintaining good hygiene,
and keeping the environment clean [10].
To prevent contact with patients’ blood and other bodily fluids as well
as contaminated surfaces and objects, healthcare workers caring for
patients with confirmed or suspected MVD should take additional
infection prevention and control procedures in addition to conventional
safety measures. Furthermore, educating people about the risk factors
for Marburg infection and the preventive measures they can take to
reduce human exposure to the virus are important steps in reducing human
infections and fatalities [10].
Furthermore, WHO advises male MVD survivors to engage in safer sexual
activities and maintain good personal cleanliness for 12 months from the
onset of symptoms until their semen has tested Marburg virus-free twice.
Body fluid contact should be avoided, and cleaning with soap and water
is advised. WHO advises against segregating male or female convalescent
patients whose blood has been tested negative for the Marburg virus
[12].
Conclusions
Equatorial Guinea and the United Republic of Tanzania are experiencing
the first ever outbreaks of the Marburg virus. Different public health
responses are being implemented in Equatorial Guinea and Tanzania,
including treating patients, locating and isolating cases and contacts,
case management, infection control, risk communication, and the
provision of hemorrhagic fever kits to health professionals who involve
in outbreak responses. The unavailability of vaccine and drugs against
MVD and the fear of its cross-border spread are major challenges. In
affected regions of Equatorial Guinea and Tanzania, surveillance and
detection efforts including contact tracing and active case finding are
recommended. Furthermore, healthcare professionals dealing with
suspected cases of MVD are advised to take additional infection
prevention and control procedures in addition to conventional safety
measures.