What is Marburg virus disease? Find out its symptoms, mode of transmission, fatality rate

Ghana has confirmed the country's first two cases of Marburg virus disease (MVD), the Ghana Health Service (GHS) has said.

The confirmation came after samples from suspected infected individuals sent to the Institute Pasteur in Dakar (IPD) tested positive for MVD, the GHS in a statement late Sunday.

The GHS first announced the suspected infections on July 7, after identifying two persons who had met the case definition of acute hemorrhagic fever in Ghana's Ashanti Region.

The samples from the individuals tested positive for MVD at the Noguchi Memorial Institute for Medical Research, Xinhua news agency reported quoting the GHS.

With assistance from the World Health Organisation (WHO), the samples were forwarded to the IPD for further confirmation.

"So far, 98 contacts have been identified, including those from the Sawla-Tuna-Kalba District of the Savannah Region," the GHS statement said. "They are undergoing quarantine and being monitored by the Ashanti and Savannah regional health directorates of the GHS."

"No new cases of MVD have been identified," the statement said.

What is the Marburg virus?

• Marburg virus disease (MVD), formerly known as Marburg haemorrhagic fever, is a severe, often fatal illness in humans.

• The virus causes severe viral haemorrhagic fever in humans.

Diagnosis

It can be difficult to clinically distinguish MVD from other infectious diseases such as malaria, typhoid fever, shigellosis, meningitis and other viral haemorrhagic fevers. Confirmation that symptoms are caused by Marburg virus infection are made using the following diagnostic methods:

• antibody-capture enzyme-linked immunosorbent assay (ELISA)

• antigen-capture detection tests

• serum neutralization test

• reverse transcriptase polymerase chain reaction (RT-PCR) assay

• electron microscopy

• virus isolation by cell culture.

Samples collected from patients are an extreme biohazard risk; laboratory testing on non-inactivated samples should be conducted under maximum biological containment conditions. All biological specimens should be packaged using the triple packaging system when transported nationally and internationally.

What is the fatality rate?

• The average MVD case fatality rate is around 50%. Case fatality rates have varied from 24% to 88% in past outbreaks depending on virus strain and case management.

• Marburg virus is the causative agent of Marburg virus disease (MVD), a disease with a case fatality ratio of up to 88%, but can be much lower with good patient care. Marburg virus disease was initially detected in 1967 after simultaneous outbreaks in Marburg and Frankfurt in Germany; and in Belgrade, Serbia.

Treatment and mitigation

• Early supportive care with rehydration, and symptomatic treatment improves survival. There is as yet no licensed treatment proven to neutralize the virus, but a range of blood products, immune therapies and drug therapies are currently under development.

• Community engagement is key to successfully controlling outbreaks.

• Currently there are no vaccines or antiviral treatments approved for MVD. However, supportive care – rehydration with oral or intravenous fluids – and treatment of specific symptoms, improves survival.

  There are monoclonal antibodies (mAbs) under development and antivirals e.g. Remdesivir and Favipiravir that have been used in clinical studies for Ebola Virus Disease (EVD) that could also be tested for MVD or used under compassionate use/expanded access.

• In May 2020, the EMA granted a marketing authorisation to Zabdeno (Ad26.ZEBOV) and Mvabea (MVA-BN-Filo). against EVD . The Mvabea contains a virus known as Vaccinia Ankara Bavarian Nordic (MVA) which has been modified to produce 4 proteins from Zaire ebolavirus and three other viruses of the same group (filoviridae). The vaccine could potentially protect against MVD, but its efficacy has not been proven in clinical trials.

How does it attack and spread?

• Initially, human MVD infection results from prolonged exposure to mines or caves inhabited by Rousettus bat colonies.

• Marburg spreads through human-to-human transmission 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.

• Health-care workers have frequently been infected while treating patients with suspected or confirmed MVD. This has occurred through close contact with patients when infection control precautions are not strictly practiced. Transmission via contaminated injection equipment or through needle-stick injuries is associated with more severe disease, rapid deterioration, and, possibly, a higher fatality rate.

• Burial ceremonies that involve direct contact with the body of the deceased can also contribute in the transmission of Marburg.

• People remain infectious as long as their blood contains the virus.

Symptoms of Marburg virus disease

• The incubation period (interval from infection to onset of symptoms) varies from 2 to 21 days.

• Illness caused by 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. In the 1967 European outbreak, non-itchy rash was a feature noted in most patients between 2 and 7 days after onset of symptoms.

• Many patients develop severe haemorrhagic manifestations between 5 and 7 days, and fatal cases usually have some form of bleeding, often from multiple areas. Fresh blood in vomitus and faeces is often accompanied by bleeding from the nose, gums, and vagina. Spontaneous bleeding at venepuncture sites (where intravenous access is obtained to give fluids or obtain blood samples) can be particularly troublesome. During the severe phase of illness, patients have sustained high fevers. Involvement of the central nervous system can result in confusion, irritability, and aggression. Orchitis (inflammation of one or both testicles) has been reported occasionally in the late phase of disease (15 days).

• In fatal cases, death occurs most often between 8 and 9 days after symptom onset, usually preceded by severe blood loss and shock.

(With inputs from WHO)