• Following reports of suspected cases of viral haemorrhagic fever in Tanzania, World Health Organisation (WHO) has enhanced its readiness to support the government as it takes measures to investigate and respond swiftly to the situation.

• The national health authorities have dispatched a team of experts to the Kagera region, where the cases of Marburg virus have been reported.

• WHO is mobilising technical expertise and logistical supplies to support these efforts. Early notification of the investigation's outcome is crucial for a swift response.

• Tanzania previously faced an outbreak of Marburg virus in March 2023, also in the Kagera region. The outbreak was controlled and declared over in less than two months due to strong measures.

• Previous outbreaks have occurred in Angola, Congo, Ghana, Kenya, Equatorial Guinea, Rwanda, South Africa, and Uganda.

Marburg Virus Disease

• Marburg virus (MARV) and Ravn virus (RAVV) of the species Orthomarburgvirus marburgense are the causative agents of Marburg Virus Disease (MVD). 

• Both viruses are part of the Filoviridae family (filovirus) to which Orthoebolavirus genus belongs. Though caused by different viruses, Ebola and Marburg diseases are clinically similar. Both diseases are rare but have the capacity to cause outbreaks with high fatality rates.

• Rousettus aegyptiacus bats are considered natural hosts for Marburg virus. There is no apparent disease in these fruit bats. As a result, the geographic distribution of Marburg virus may overlap with the range of Rousettus bats.

• Marburg Virus Disease (MVD) is a highly virulent disease that causes haemorrhagic fever, with a fatality ratio of up to 88 per cent.

• Two large outbreaks that occurred simultaneously in Marburg and Frankfurt in Germany, and in Belgrade, Serbia, in 1967, led to the initial recognition of the disease. The outbreak was associated with laboratory work using African green monkeys (Cercopithecus aethiops) imported from Uganda. Subsequently, outbreaks and sporadic cases have been reported in Angola, Democratic Republic of the Congo, Kenya, South Africa (in a person with recent travel history to Zimbabwe) and Uganda.

Transmission

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

• Rousettus aegyptiacus bats are considered natural hosts for Marburg virus.

• 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 (bedding, clothing) contaminated with these fluids.

• Health care workers have frequently been infected while treating patients with suspected or confirmed MVD.

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

Symptoms of Marburg Virus Disease

• 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. 

• The appearance of patients at this phase has been described as showing “ghost-like” drawn features, deep-set eyes, expressionless faces, and extreme lethargy. 

• Many patients develop severe haemorrhagic manifestations between five and seven days, and fatal cases usually have some form of bleeding, often from multiple areas.

• During the severe phase of illness, patients have sustained high fevers. 

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

• It can be difficult to clinically distinguish MVD from other infectious diseases such as malaria, typhoid fever, shigellosis, meningitis and other viral haemorrhagic fevers.

• Antigen-capture enzyme-linked immunosorbent assay (ELISA) testing, polymerase chain reaction (PCR), and IgM-capture ELISA can be used to confirm a case of MVD within a few days of symptom onset. 

Treatment

• 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.

• A range of potential treatments, including blood products, immune therapies and drug therapies, are being evaluated.

• Outbreak control relies on using a range of interventions, namely case management, surveillance and contact tracing, a good laboratory service, safe and dignified burials, and social mobilisation.

Manorama Yearbook app is now available on Google Play Store and iOS App Store