Understanding HMPV, H5N1 & Marburg Virus: What You Need to Know

Written by Dr Melinda Dimitriou

Infectious diseases continue to be a global health concern, with viruses like Human Metapneumovirus (HMPV), Avian Influenza A (H5N1), and the Marburg virus making headlines in 2025. While these viruses can cause illness in humans, understanding their transmission, symptoms, and preventative measures can help protect individuals and communities. Here’s what you need to know about each of these viruses:

Human Metapneumovirus (HMPV)

What is HMPV?

HMPV is a respiratory virus first identified in 2001. It spreads through respiratory droplets, contaminated surfaces, or direct contact with an infected person. The incubation period is typically 3–5 days, and symptoms include cough, fever, nasal congestion, and sore throat. Severe cases can lead to pneumonia or bronchiolitis, particularly in high-risk groups like young children, the elderly, and immunocompromised individuals.

Current Situation in South Africa

HMPV is present year-round in South Africa, with no defined seasonal pattern. According to the National Institute for Communicable Diseases (NICD), there is no current cause for alarm, as it remains a commonly occurring respiratory virus.

Prevention Tips:

• Wash hands regularly with soap and water.
• Avoid close contact with individuals displaying respiratory symptoms.
• Clean and disinfect frequently touched surfaces.

Avian Influenza A (H5N1) – “Bird Flu”

What is H5N1?

H5N1 is a subtype of the influenza A virus that primarily affects birds but can infect humans in rare cases. Human infections, though uncommon, can be severe. The virus is transmitted through direct contact with infected birds, their droppings, or contaminated environments. Human-to-human transmission is rare, but ongoing surveillance is crucial.

Current Global Updates

H5N1 remains enzootic in many bird populations worldwide. To date, 67 confirmed human cases have been reported—23 linked to poultry exposure and 44 related to dairy cow outbreaks. Fortunately, there have been no confirmed cases of human-to-human transmission.

Symptoms of H5N1:

• Fever, cough, sore throat, and muscle aches
• Severe respiratory illness, including pneumonia

Virulence and Mortality:

H5N1 has a high case fatality rate of approximately 50%, though experts suggest this may be overestimated due to undetected mild or asymptomatic cases.

Prevention Tips:

• Avoid contact with sick or dead poultry and wild birds.
• Cook poultry products thoroughly before consumption.
• Use protective gear like masks when handling birds in occupational settings.
• Avoid consuming unpasteurized milk.

Pandemic Risk Assessment

The CDC currently assesses the risk of H5N1 to humans as "moderate." Experts estimate the likelihood of an H5N1 pandemic in 2025 at around 7–9%, an increase from previous estimates of 5% in 2024.

Marburg Virus Disease (MVD)

What is the Marburg Virus?

Marburg virus belongs to the same family as Ebola and causes severe hemorrhagic fever. It is primarily transmitted to humans through exposure to fruit bats, particularly in caves and mines, and spreads between humans via direct contact with infected bodily fluids.

Current Outbreaks

As of January 2025, a suspected Marburg outbreak has been reported in Tanzania's Kagera region, with six confirmed cases and five fatalities. The World Health Organization (WHO) is actively involved in containment efforts.

Symptoms of Marburg Virus:

• Sudden onset of high fever, severe headache, and malaise
• Severe hemorrhagic symptoms in later stages

Virulence and Mortality:

MVD has a case fatality rate ranging from 24% to 88%, depending on healthcare quality and outbreak circumstances.

Prevention Tips:

• Avoid caves or mines inhabited by bats.
• Follow strict infection control measures when caring for patients.
• Use personal protective equipment when handling bodily fluids.
• Practice safe burial procedures for deceased patients.

Final Thoughts

While these viruses pose potential health risks, awareness and precautionary measures can significantly reduce the likelihood of infection. Stay informed through trusted sources like the NICD, CDC, WHO, and local health authorities. By practicing good hygiene, following public health guidelines, and staying updated on disease outbreaks, individuals and communities can contribute to global health security.