Marburg virus disease, previously known as Marburg haemorrhagic fever, is caused by the Marburg virus and is a severe and fatal disease in humans. The Marburg virus can be spread through human-to-human; however, it originates from fruit bats and is transmitted to humans from them. It causes severe haemorrhagic (excessive bleeding) fever in humans. However, early symptoms can be confused with other viral haemorrhagic fevers and other infectious diseases.¹ This highlights the importance of understanding the different viruses that cause similar infections to Marburg virus disease such as Ebola, as it will improve swift diagnosis and early treatment. This article discusses the differences between the Marburg virus and other similar viruses that cause disease in humans.

Introduction

Marburg virus is a member of the Filoviridae family, also known as filoviruses, and has a long, thread-like shape. The family includes 6 types of viruses: Marburgvirus, Ebolavirus, Cuevavirus, Dianlovirus, Striavirus, and Thamnovirus. Both Marburgvirus and Ebolavirus can cause disease in humans. The Marburgvirus genus contains two species: Marburg virus and Ravn virus, which are both pathogenic to humans.³ The first incidences of a new disease were reported in 1967 in West Germany and Yugoslavia; they were described as experiencing high fever, haemorrhaging (excessive bleeding) and organ failure. However, it wasn’t until 1975 that the virus responsible for the illness was defined as the Marburg virus. It was later discovered that Marburg virus disease is zoonotic, meaning it is transmitted from animals to humans. Specifically, outbreaks have been found in humans having been near mines where bat colonies reside. It is now understood that the Marburg virus is present in Egyptian Roulette bats (Rousettus aegyptiacus).²

How is the marburg virus disease transmitted?

Marburg virus disease spreads human-to-human via direct contact with blood, secretions, organs or other bodily fluids of a person with the disease, or indirectly through surfaces and materials contaminated with infected fluids. Healthcare workers who do not follow strict infection control precautions may get infected while caring for Marburg virus disease patients. Additionally, burial ceremonies that involve direct contact with the disease-infected body of the deceased can also contribute to its transmission.

Symptoms of marburg virus disease

Symptoms of Marburg virus disease are severe. There is no cure or specific treatment for the disease, which contributes to its high death rate of up to 88%. Marburg virus disease symptoms usually start abruptly, most commonly experienced are:

• High fever
• Headache
• Severe malaise
• Muscle aches

The following symptoms usually start on day 3 of infection:

• Watery diarrhoea –  may last for a week
• Vomiting – usually starts at day 3
• Abdominal pain/ cramping – usually starts at day 3
• “Ghost-like” drawn features
• Deep-set eyes
• Lethargy (extreme tiredness)

In most cases, between days 5 and 7, this common symptom may occur:

• Haemorrhagic manifestation – bleeding in multiple areas, such as nose, vagina, gums, blood in vomit and faeces

As the disease progresses, confusion, aggression, irritability and orchitis (inflammation of the testicles) can be experienced, especially within the late phase of the disease. In fatal cases, severe blood loss and shock may result in death, usually occurring between 8 and 9 days.²

Marburg virus in comparison with other viruses

Let's explore how it differs from other viruses, notably those that cause similar haemorrhagic fevers.

Ebola virus

Ebola is a rare, often fatal, viral disease in humans. Like the Marburg virus, the Ebola virus that causes the disease belongs to the Filoviridae family. Humans become infected with the Ebola virus when they come in contact with blood, secretions or other bodily fluids of animals that are the natural hosts of the virus or are infected with Ebola, such as primates and, like the Marburg virus, fruit bats. Ebola spreads like the Marburg virus, through human-to-human transmission via direct contact with infected bodily fluids.⁵

The symptoms of Ebola are very similar to Marburg disease. These can be fatigue, headache, vomiting, diarrhoea, sore throat and internal and external bleeding (haemorrhaging). According to the World Health Organisation, Case fatality rates can vary between 25–90%.⁵

Key differences between ebola and marburg virus disease

• Transmission: The Ebola virus can remain in the body longer than the Marburg virus; pregnant women can pass the virus to their baby whilst breastfeeding and the virus can linger in the semen therefore patients must be cautious during sexual intercourse
• Fatality: Ebola can be slightly more fatal than the Marburg virus. (up to 90% vs 88%)
• Treatment: Ebola has vaccines to protect against the spread of the disease, unlike the Marburg virus disease with no available vaccines⁵

Lassa fever

Lassa Fever is another haemorrhagic fever and is caused by the Lassa virus, caused by a family of viruses called arenavirus. The symptoms of Lassa fever are varied and non-specific, they include typical haemorrhagic fever-associated symptoms such as headache, sore throat, nausea, vomiting, diarrhoea, muscle pain and internal and external bleeding. In fatal cases, death can occur within 14 days and similar to Marburg virus disease, there is currently no licensed vaccine for Lassa fever. Prevention of Lessa fever relies on maintaining good hygiene, this ensures little to no rodents enter the home and contaminate food. Storing food in sealed containers is also advisable⁶.

Key differences between ebola and marburg virus disease

• Transmission: Humans become infected with the Lassa virus when consuming contaminated foods with urine or faeces of infected Mastomys rats
• Symptoms: People with the Lessa virus may experience seizures during the late stages of the disease, and hair loss and deafness may be experienced during recovery
• Treatment: The antiviral drug ribavirin has been used to treat Lessa fever, however, it is not yet licensed as a treatment for Lassa fever⁶

Crimean-congo fever virus

The Crimean-Congo haemorrhagic fever virus, also known as Nairovirus, causes severe viral haemorrhagic fever outbreaks. The virus is found in ticks. From the infected person, human-to-human transmission can occur via contact with blood and other bodily fluids, similar to Marburg virus disease. Non-sterile medical equipment used in hospitals is also the cause of transmission. Like other haemorrhagic fever viruses, the symptoms are the same, ranging from flu-like symptoms to gastrointestinal issues. The antiviral drug ribavirin has been used to treat Crimean-Congo haemorrhagic fever, but no vaccines are currently available to prevent the spread of the disease.⁷

Key differences between crimean-congo fever virus and marburg virus disease

Transmission: Through tick bites or being in close contact with animals that have been bitten by ticks, making veterinarians, agricultural workers and slaughterhouse workers more likely to get infected.

Symptoms: Patients can experience an array of further symptoms not found in Marburg virus disease cases, such as fast heart rate and petechial rash, which is a rash caused by bleeding onto the skin.

Death rate: This is a lot lower in Crimean-Congo haemorrhagic fever cases compared with Marburg virus disease, with up to 30%⁷

Other haemorrhagic fever viruses

We have touched upon various common haemorrhagic fever viruses, however, there are four families of viruses (Arenaviridae, Bunyaviridae, Filoviridae, and Flaviviridae) that can cause similar diseases to Marburg virus disease. One other common disease in regions of tropical weather is Dengue fever, transmitted through mosquitoes. To summarise, all haemorrhagic fever viruses share characteristics of being mainly zoonotic with the ability to cause mild to severe, and sometimes fatal, symptoms. These symptoms tend to be flu-like and nonspecific.⁸

Conclusion

Marburg virus disease is a severe and often fatal illness caused by the Marburg virus, which comes from fruit bats. It was first identified in 1967 and causes high fever, severe headaches, muscle pain, and, after a few days, symptoms like watery diarrhoea and vomiting. Unfortunately, the death rate is 88%, mainly due to it having no treatment or vaccine. The virus spreads human-to-human via direct contact with the bodily fluids of infected patients, this leads to the healthcare settings and certain burial practices are high-risk places where transmission can be made.

Differentiating Marburg virus disease from other similar diseases is important, especially since its early symptoms are non-specific and begin with flu-like symptoms. Both the Ebola and Marburg virus belong to the same viral family and share similar transmission routes, however, Ebola can remain in the body longer and in some cases, has a higher death rate. Crimean-Congo and Dengue fever on the other hand are both caused by different viruses that transmit disease via insect bites (ticks for Crimean-Congo fever and mosquitoes for Dengue fever). Whereas, Lassa fever is transmitted by ingesting rat-contaminated food. These diseases pose significant health threats, highlighting the importance of having faster ways to tell them apart so that they aren’t mistaken for one another and the right care can be given promptly.