Introduction 

Marburg is a rare and severe viral disease that can infect humans and primates, such as apes and monkeys. It is caused by either the Marburg or the Ravn virus and is categorised under viral hemorrhagic fevers (VHFs).¹ Although different viruses cause Ebola and Marburg, they are medically similar because they belong to the same family of viruses known as Filoviruses. Both diseases are rare but have the potential to lead to outbreaks with high mortality (death) rates.

The disease can cause severe illness by damaging small blood vessels, leading to leaks and affecting blood clotting. Symptoms often appear suddenly, with immediate onset. However, cases in adolescents and children are sporadic, with only a few documented instances.²

Cases of Marburg virus disease (MVD) are severe, with an average fatality rate of around 50%. However, this rate has varied between 24% and 88% in past outbreaks.³ Survival rates can be significantly higher with prompt and effective patient care. Up to 9 out of 10 people infected with the virus will die without treatment, with the chance of survival improving when treatment is given early.

Understanding MVD is crucial, especially considering its impact on different demographics. This viral hemorrhagic fever, caused by the Marburg or Ravn virus, poses an enormous threat with varying effects on children, adolescents, and adults. This article will clarify how these groups are affected and how we can manage the risks associated with this disease.

Understanding marburg virus

The disease is named after the German city of Marburg, where the virus was first identified in 1967 when scientists were handling monkeys imported from Africa. Since then, outbreaks and sporadic cases have been reported in countries such as Angola, Equatorial Guinea, the Democratic Republic of the Congo, Ghana, Guinea, and Kenya.²

The MVD viruses are primarily found in the Egyptian rousette fruit bat, Rousettus aegyptiacus. Human infections often occur among individuals who have prolonged exposure to environments where these bats reside, such as mines or caves. Additionally, research indicates that pigs can contract the virus, potentially increasing its spread. Thus, implementing measures to prevent pigs from coming into contact with infected bats is crucial to control the transmission of viruses.⁴

Once the Marburg virus enters the human population, it can spread from person to person; this happens when someone comes into contact with the bodily fluids of an infected person, such as blood, through broken skin or mucous membranes. Additionally, the virus can spread by touching surfaces or materials contaminated with these infected fluids, like bedding and clothing. This places healthcare workers who care for infected individuals and close family members of the infected person at a higher risk of contracting the illness.

Most at risk from severe illness

Pregnant women, children, and individuals in the late stages of this illness are at a higher risk of mortality from Marburg virus disease. This increased vulnerability is often attributed to their weaker immune systems, which put them at greater risk of experiencing severe effects from the virus.

Those with direct contact with infected fruit bats, particularly primary cases, tend to experience the most severe symptoms. The Marburg virus affects children and adolescents differently from adults, primarily due to their developing immune systems. Here are the key differences:

• Immune response: Children and adolescents could have less robust immune responses than adults, making them more susceptible to severe disease manifestations
• Symptom severity: While adults often show severe symptoms quickly, children could present with nontypical symptoms, which can make diagnosis difficult and lead to delayed treatment
• Outcome variability: The mortality rate can be more pronounced in younger populations because their bodies can struggle more with the impacts the virus has on the whole body

Transmission and risk factors of MDV for children and adolescents

Most primary cases of infection are typically linked to work in mines or caves due to prolonged exposure to the infected Egyptian rousette fruit bat or its excretions. Due to this, it is unlikely to see children as the primary infected group.

The second most significant risk factor for contracting MDV is caring for individuals with this condition, which is commonly associated with older family members or healthcare workers; therefore, this could explain the transmission of the virus to older children and adolescents, but might not explain the transmission to young children. 

The spread of the virus from person to person through contact with the bodily fluids of an infected individual could be a possible way for young children to become infected with MDV; in particular, this is a risk for very young children who are being breastfed by an infected mother, or are in close contact with their infected primary caregiver or family member. The control of an outbreak is essential to increase survival rates.⁵ Raising community awareness and educating the public is the most effective way to manage an outbreak. Control of an outbreak requires several vital actions: managing cases, monitoring health, tracing contacts, providing quality lab services, preventing and controlling infections in healthcare settings, ensuring safe and respectful burials, and mobilising the community. By informing people about the risk factors for MVD and the protective steps they can take, we can help reduce the spread of the disease and protect entire communities, including adolescents and children.⁶

Symptoms

Recognising MVD in children can be difficult because early symptoms are broad and unclear, with travel history essential for identification. Recently, there have been outbreaks in Tanzania, from March to May 2023, and Equatorial Guinea, from February to June 2023. The MVD symptoms usually start 2 to 21 days after contact with the Marburg virus.

Common MVD symptoms include:

•  High fever
•  Severe tiredness
•  Red eyes
•  Intense headache
•  Muscle aches and pains
•  Non-itchy rash with flat and raised bumps
•  Chest pain
•  Sore throat
•  Severe nausea, vomiting, and watery diarrhoea with abdominal pain and cramping

Symptoms often worsen after day five and may begin to show bleeding, such as:

•  Fresh blood in vomit or diarrhoea
•  Bleeding from the nose, gums, and vagina
•  Bleeding at sites where intravenous needles were used
•  Confusion, irritability, or aggression
•  Swelling of one or both testicles

As the disease progresses, it can be fatal. Symptoms may then include:

•  Liver failure
•  Delirium
•  Shock
•  Severe bleeding
•  Multi-organ dysfunction

Treatment

No vaccines or antiviral treatments are approved for MVD, and treatment is limited to supportive care, such as rest, hydration, and managing oxygen status and blood pressure. Furthermore, secondary infections (infections during or after treatment of another infection) may require treatment. The early onset of supportive care can improve survival. However, the Marburg virus is a severe and deadly illness with a 20-90% mortality rate.

It is possible for the Marburg virus to still be present in some bodily fluids in those that have survived, such as semen, fluid inside the eye, and the placenta, amniotic fluid, and fetus of women infected while pregnant, and in the breast milk of women infected while breastfeeding. Although rare, relapse-symptomatic illness, the presence of reinfection in someone who has recovered from MVD, has been documented but not yet fully understood. Additionally, it has been noted that the Marburg virus has been transmitted via infected semen up to 7 weeks after clinical recovery. Counselling should be offered to male survivors and their sexual partners, to inform them of potential risks and advise on safe sex practices to prevent transmissions. 

Summary

• Marburg virus disease (MVD) is a rare and severe viral disease that can infect humans and primates, such as apes and monkeys
• Cases of MVD are rare
• The viruses that cause MVD are naturally found in the Egyptian rousette fruit bat and can spread from bats to humans
• Person-to-person transmission occurs when someone comes into contact with an infected person's bodily fluids, such as blood or semen, through broken skin or mucous membranes
• The virus can be spread by touching surfaces or materials contaminated with the infected fluid, such as bedding and clothing
• Up to 9 out of 10 people infected with the virus will die without treatment
• Currently, no vaccines or antiviral treatments have been approved for MVD
• Pregnant women, children, and those who are late in the course of illness are at higher risk of dying from MVD
• Effective outbreak management relies on various interventions, including case management, surveillance, contact tracing, quality laboratory services, infection prevention and control in healthcare facilities, safe and dignified burials, and isolation of the infected
• Raising awareness of risk factors for MVD and protective measures that individuals can take is an effective way to reduce the spread of the disease from person to person, and aid in the protection of whole communities, including young children and adolescents