Michelle J. Groome
Head of the Division of Public Health Surveillance and Response, National Institute for Communicable Diseases
Head of the Center for Emerging and Zoonotic Diseases, National Institute for Communicable Diseases
As the COVID-19 pandemic rages on in Africa amid insufficient vaccination rollout, viral haemorrhagic fever has again raised its head. This adds to public health turmoil on the continent where resources to respond to emerging and re-emerging epidemic prone zoonotic diseases remain limited.
In the first week of August 2021, a Marburg virus disease outbreak was declared in south-western Guinea. This was the same area in which the recent outbreak of Ebola virus disease occurred and only weeks after the end of the Ebola outbreak was declared.
To date, 14 outbreaks of Marburg virus disease have been reported since 1967. These have been mostly in sub-Saharan Africa. The most recent case in Guinea is the first reported in West Africa. However, evidence of Marburg virus circulation has been reported from countries where Marburg virus disease cases have not been diagnosed to date. These include Gabon, Zambia, and Sierra Leone.
The first recognised outbreak of Marburg virus disease in Africa occurred in 1975 in South Africa. It was an imported case from Zimbabwe. Imported cases from Uganda were reported in 2008 in the US and the Netherlands and one laboratory infection was diagnosed in Russia in 2004. To date the largest and deadliest outbreak occurred in Angola in 2004–2005.
Recurrent outbreaks of viral haemorrhagic fevers are a major burden on countries such as Guinea where health care systems are already under threat.
Fortunately, many African countries are experienced in managing outbreaks of viral haemorrhagic fevers. Guinean health authorities have been able to respond rapidly and implement measures learnt during the Ebola outbreak to control the spread of Marburg. This has included rapid deployment of multidisciplinary teams, diagnosis, contact tracing, isolation and treatment of patients.
The existence of treatment centres greatly facilitated rapid treatment of suspected cases and confirmed cases, and medical expertise improved patient care.
Marburg virus belongs to the same family as the Ebola viruses. It causes sporadic, but often fatal disease in humans and non-human primates. Studies implicate the Egyptian rousette bat, Rousettus aegyptiacus (Pteropodidae family), as the prime reservoir host. Entering the roosting habitats, including caves and mining activities have been associated with Marburg virus transmission to humans.
The virus is transmitted by direct contact with the blood, bodily secretions and/or tissues of infected persons or wild animals, for example monkeys and bats. It can also be transmitted through contact with surfaces and materials like bedding or clothing contaminated with these fluids.
The incubation period varies from 2 to 21 days. Symptoms include fever, malaise, body aches, nausea, vomiting, diarrhoea, and internal haemorrhaging (bleeding).
Marburg virus can be difficult to distinguish from other tropical common febrile illnesses, because of the similarities in the clinical presentation. Based on the laboratory confirmed cases, infection with Marburg virus can result in death in 23% to 90% of patients.
There is no specific antiviral treatment or preventative vaccine. Supportive care includes intravenous fluids, replacement of electrolytes, supplemental oxygen, and replacement of blood and blood products may significantly improve the clinical outcome.
Marburg virus can spread easily between people if appropriate preventive measures are not in place. These include personal protection, barriers nursing, safe management of funerals, case finding, contact tracing, isolation and treatment of patient.
The virus is potentially prone to cause formidable epidemics with serious public health consequences.
The area in Guinea where the case of Marburg virus disease was detected shares close borders with Sierra Leone and Liberia. The movement of people locally and across borders could lead to the potential spread. That’s why the following steps are key:
the deployment of well-prepared response teams at national and district level.
surveillance and coordinated efforts within and between countries.
surveillance at points of entry.
contact tracing and active case finding in health facilities and at the community level.
investigations aiming at identification of the source of the infection.
laboratory testing without delay.
It is also vitally important to educate the public and raise community awareness about the risk factors and the protective measures individuals can take to reduce their exposure. These include:
avoiding close physical contact with someone who is thought to have contracted the virus.
the transfer of any suspected case to a health facility for treatment and isolation.
the immediate and safe burial of people who have died from the virus.
the use of infection prevention and control precautions by health-care workers caring for patients with suspected or confirmed Marburg virus disease. This is to avoid any exposure to blood and/or bodily fluids, as well as unprotected contact with a possibly contaminated environment.
wildlife to be handled with gloves and appropriate protective clothing to reduce the risk of spread.
animal products (blood and meat) to be cooked thoroughly before eating. Raw meat should be avoided.
Community involvement is essential to respond effectively and control an outbreak. This must be supported by primary health care systems to gain greater participation and commitment.
What needs to be fixed
A number of factors get in the way of researching, responding to and controlling zoonotic diseases in Africa. These include:
insufficient and un-coordinated surveillance and research programmes.
limited regional capacity to develop new and improved diagnostic assays.
shortage of maximum containment facilities.
lack of strategic biobanks for long-term and secure storage of reference clinical materials, strains and pathogen biodiversity.
lack of regional External Quality Assurance programmes for dangerous endemic viral and bacterial pathogens.
A timely, streamlined, well-funded and efficient disease reporting and surveillance system is essential to monitor the threat of potential epidemics. To strengthen the efficiency of responding quickly, each nation must improve its own capacity in disease recognition and laboratory competence.
We also need innovative African-driven approaches to make the necessary quantum leap in the development of scientific capacity for surveillance and control of infectious diseases.
Global initiatives aiming at improving health security, emergency preparedness and health systems are also important. However, a great deal of work is needed at the higher level of national governance to strengthen resilience and reduce vulnerability.