HUMAN METAPNEUMOVIRUS (hMPV)

Annelies Van Den Bergh is a 3^rd year PhD candidate at the Institute for Glycomics working under the supervision of Dr Larissa Dirr and Professor Mark von Itzstein AO.  Annelies’ research project focuses on a virus that affects the respiratory system that many people may not be familiar with. In fact, it has not been around for all that long. The virus in question is called Human Metapneumovirus (prononouced meta-new-mo-virus), or hMPV in short. 

But what exactly is hMPV, who is more at risk of severe illness, and how is the Institute’s research combatting this particular pathogen?  Annelies delves into all these questions and more…

So, what is Human Metapneumovirus (hMPV)?

hMPV is a viral pathogen (a virus), which means that it needs human cells and their machinery to replicate. More specifically, hMPV is a respiratory virus, which means that it can infect the cells of the respiratory tract (the nose, throat, and lungs). Once infected, the cells can no longer function normally, becoming ‘sick’, which leads to symptoms such as a runny nose, fever, sore throat, shortness of breath, and/or a cough. The typical symptoms are not usually severe, however if hMPV continues to spread to the lower respiratory tract, it could lead to more serious illnesses like pneumonia or bronchiolitis.

In extreme cases where hMPV infection leads to severe pneumonia or bronchiolitis, patients struggle to breathe sufficiently on their own and need to be admitted to the intensive care unit for close monitoring. Fortunately, most hospitals are capable of managing this shortness of breath, but immunocompromised patients and those with underlying medical conditions can be severely affected by hMPV.

The greatest threat occurs in those circumstances where a patient suffering from pneumonia is infected by a second pathogen (either viral or bacterial). This usually exacerbates symptoms and, due to a weak immune system in these patients, it can cause death.

A little history about hMPV

hMPV infection was first discovered in humans in 2001 by a group of researchers in the Netherlands, however avian (bird) metapneumovirus has been around since the 1970s.

Back then it was identified that hMPV is a member of the same viral family – called Pneumoviridae – that also includes respiratory syncytial virus (RSV). These viruses have structural similarities and they also infect specific groups within our populations. Children under the age of two, the elderly, and people who are immunocompromised, such as transplant patients, are most at risk of contracting hMPV.

Transmission – what you need to know

hMPV is an infectious disease which means it is easily spread from person to person in a similar way as other respiratory viruses – through secretions from coughing and sneezing, close personal contact, such as touching or shaking hands, and touching the mouth, nose or eyes after touching objects or surfaces that have been contaminated by the virus.

hMPV infections are not endemic to any particular region but occur periodically around the world. A peak in infections is observed during the winter months when it is cold outside, and people don’t go out as much. During this time, people are more susceptible to infections as their immune system is weakened, and this makes it easier for any pathogen, like hMPV, to infect people. Interestingly, the infection peak for hMPV is usually seen at the end of winter and early spring.

The exact global impact of hMPV is difficult to predict as not every case is reported, but global studies have indicated that every child under the age of five has encountered hMPV at one point in their life, with the percentage of children who are hospitalised due to an hMPV infection being 10-12%.

If the symptoms of hMPV are so similar to those of cold and flu-like symptoms, how can you determine if you indeed have hMPV?

Because the symptoms are very similar to other respiratory viruses, additional tests will need to be carried out by health care professionals in certified facilities to determine whether or not you have an hMPV infection. Common diagnostic tests include a throat swab, saliva sample or blood sample.

Current treatment options

Although there have been many advances made since its discovery, there are currently no effective drugs or vaccines available to treat or prevent hMPV infections.

It’s a common misconception that antibiotics are effective against viral infections, as this is not the case. Antibiotics are ineffective against viruses, for example some of them work by destroying the cell wall of bacteria, but viruses like hMPV have a distinctly different membrane structure. So, antibiotics would have no effect in the treatment of an hMPV infection.

What does your hMPV research project specifically focus on?

My project focuses on how hMPV is able to bind to human cells by using a range of different techniques. We have already identified that one viral protein is essential in the lifecycle of hMPV and we are now working hard to understand how this protein interacts with the human host cell receptors.

Once we understand this, we can design potential drug compounds that are highly effective and specific in blocking the interaction between the viral protein and human host cell receptors. Additionally, I have screened a large library of FDA-approved drugs against hMPV to identify hits that can potentially be repurposed as an anti-hMPV drug. Ultimately, we like to combine our new insights to design an anti-hMPV drug that is highly effective and causes very few side effects.

How does the Institute for Glycomics’ resources help facilitate research into pathogens like hMPV?

Here at the Institute for Glycomics, research led by Dr Larissa Dirr and Professor Mark von Itzstein AO is focused on understanding how hMPV behaves and spreads in the human body and how we can use this information to design effective drugs that can treat the infection.

The high calibre of research facilities and expertise within the Institute for Glycomics, combined with its multidisciplinary research approach centred around the research field Glycomics, makes it both specialised and unique.

For example, many different facilities and highly experienced staff within the Institute enable us to first identify an interesting and potential drug target. Next we use structural insights to design and synthesise potential compounds of interest in-house that we then evaluate in a wide range of physiological relevant models such as an ex vivo human airway epithelial cell model and in vivo models. Ultimately, all steps are combined to efficiently target a pathogen and speed up the drug discovery process.