According to the World Health Organisation (WHO) and the US Centre for Disease Control and Prevention (CDC), Marburg virus disease (MVD) is a rare but severe virus that causes hemorrhagic fever that affects both people and non-human primates. It has a fatality ratio of 88%.
MVD is caused by the Marburg virus, a genetically unique zoonotic (or animal-borne) RNA virus of the filovirus family; same family as the virus that causes Ebola.
History
Marburg virus was first recognised in 1967, when outbreaks of hemorrhagic fever occurred simultaneously in laboratories in Marburg and Frankfurt, Germany and in Belgrade, Yugoslavia (now Serbia).
The first people infected had been exposed to Ugandan imported African green monkeys or their tissues while conducting research. Other outbreaks have also been reported in Europe and the United States.
In Africa, previous outbreaks have been reported in Angola, the Democratic Republic of the Congo, Kenya, South Africa and Uganda.
According to the Nigeria Centre for Disease Control (NCDC), this would be the second time the zoonotic disease has been detected in West Africa, following the previous incidence in Guinea in August 2021.
Transmission
The reservoir host of the Marburg virus is the African fruit bat, Rousettus aegyptiacus. Fruit bats infected with Marburg virus do not show obvious signs of illness. Primates (including people) can become infected with the Marburg virus and may develop serious disease with high mortality.
Human infection with the disease initially resulted from prolonged exposure to mines or caves inhabited by Rousettus bat colonies. Marburg can spread from human-to-human via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids.
Resurgence
Few days ago, health authorities in Ghana officially confirmed two cases of the highly infectious virus in the country, after the death of two people on July 10 who had previously tested for the virus.
The Ghana Health Service said a total of 98 people have been identified as contact cases and are currently under quarantine, with no new cases detected in the country yet.
The development has led NCDC to heighten surveillance at the borders and all other entry points to the country, as it warns citizens that the country faces moderate risk of importation.
The statement, which was signed by the Director General of the NCDC, Dr. Adetifa, reads in part: “NCDC is aware of the declaration of an outbreak of MVD in Ghana confirmed by the WHO on the 17th of July, 2022.
“Given the proximity of Ghana to Nigeria as well as the WHO alert, the NCDC-led multisectoral National Emerging Viral Haemorrhagic Diseases Working Group (EVHDWG) that coordinates preparedness efforts for MVD, and other emerging viral haemorrhagic diseases has conducted a rapid risk assessment to guide in-country preparedness activities.
“Based on available data, the overall risk of both importation of the disease and its potential impact on the Nigerian population is said to be moderate as assessed by NCDC experts and partners given the proximity (same region), high traffic from Ghana and countries that share borders with Ghana, the incubation period of 21 days of the virus, heightened surveillance at point of entry, Nigeria’s capacity to respond to the outbreak in the country and the fact that persons with MVD transmit the virus when they become symptomatic, unlike for SARS-CoV-2 that causes COVID-19 that can also be transmitted by infected persons without symptoms.”
Symptoms
According to WHO, illness caused by the Marburg virus begins abruptly, with high fever, severe headache and severe malaise. Muscle aches and pains are a common feature. Severe watery diarrhoea, abdominal pain and cramping, nausea and vomiting can begin on the third day. Diarrhoea can persist for a week.
The appearance of patients at this phase has been described as showing “ghost-like” drawn features, deep-set eyes, expressionless faces and extreme lethargy. A non-itchy rash has been noted between two and seven days after the onset of symptoms.
Fatal cases usually have bleeding, often from multiple areas and sustained high fevers. Fresh blood in vomit and faeces is often accompanied by bleeding from the nose, gums and vagina. Involvement of the central nervous system can result in confusion, irritability and aggression. Orchitis (inflammation of the testicles) has been reported occasionally in the late phase (15 days).
In fatal cases, death usually occurs between eight and nine days after onset, usually preceded by severe blood loss and shock.
Prevention and treatment
While there is yet no proven treatment available for Marburg, a range of potential treatments, including blood products, immune therapies and drug therapies are currently being evaluated. There are also no vaccines or antiviral treatments currently approved for MVD.
However, as part of measures to prevent the disease, the NCDC advised that people who exhibit the symptoms should ensure they are promptly taken to healthcare facilities for diagnosis and initiation of supportive treatment, which improve chances of survival.
“Other health advisories approved by the NCDC include, strict practice of infection prevention control in the healthcare setting for all suspected patients, survivors of Marburg virus disease should practice safer sexual practices and hygiene for 12 months from onset of symptoms or until their semen tests negative twice for the virus infections,” it said.
Also, the NCDC boss advised Nigerians to avoid non-essential travel to locations where the outbreak has been reported and prevent direct contact with the blood, saliva, vomit, urine and other body fluids of people with suspected or confirmed Marburg virus disease.
This explainer is produced in partnership with the Centre for Democracy and Development (CDD).
