University of Alberta experts say the world needs to do more to prepare for outbreaks of deadly viruses such as Ebola, hantavirus and others, even though the current risk remains low.

Their warning comes as the World Health Organization declared a public health emergency of international concern this week after more than 600 Ebola cases and 139 deaths were reported in the Democratic Republic of Congo.

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University of Alberta researcher says the outbreaks are serious, but they do not point to a new global pandemic.

While both Ebola and hantavirus infections can be severe, neither virus spreads efficiently at a global level, unlike COVID-19. As a result, their pandemic potential remains very low based on what is known today.

The experts say it is important to distinguish between how severe a disease can be and how easily it spreads. In both cases, the disease can be serious, but broad community transmission remains limited.

The threat from both outbreaks is minimal, but the events are a reminder that not all the lessons from the COVID-19 pandemic have been learned.

Vaccines and antibodies developed to fight the last major Ebola outbreak in West Africa in 2014 were designed for the Zaire strain and will likely not work against the new Bundibugyo strain, Matthias Götte, the University of Alberta expert explains.

The current Ebola outbreak is already the 17th in the Democratic Republic of Congo since the virus was first detected in 1976. It may have been made worse by an unsafe open-casket funeral and delayed detection in a population that was not fully informed about the risks. The disease becomes more infectious as it progresses, with the highest risk coming in the later stages, especially during care of very ill patients and at funerals.

Ebola virus disease can cause systemic organ failure and kills about half of those infected. It spreads through direct contact with bodily fluids, making family members and health-care workers the most vulnerable.

The current outbreak is taking place in an area affected by conflict and famine, which can make people more susceptible to disease, including viral infections. There are also reports of cases in Uganda, and there are concerns about possible spread to neighbouring South Sudan.

University of Alberta researcher, who study RNA viruses with high epidemic potential, say it is difficult to keep up with these viruses because they are diverse and constantly changing.

“This is quite typical for RNA viruses like Ebola, hantavirus, SARS-CoV-2 and influenza. They are very sloppy in the way they replicate, and that means they create mutations. And some of them adapt very quickly,” one expert says.

This is why the flu vaccine is reviewed each year to ensure it can protect against the dominant strains in circulation.

The University of Alberta team says it can take months to develop new vaccines and years to develop new drugs, so the best hope for containing the current Ebola outbreak may come from clinical trials set to begin for two existing drugs.

One is MBP134, a combination of two existing antibody treatments known to target several Ebola strains. The second is remdesivir, an antiviral drug originally developed to fight the Zaire Ebola strain. The two drugs may also be tested together because they target the virus in different ways.

Researchers at the University of Alberta helped identify the mechanism behind remdesivir and its antiviral activity against Ebola and SARS-CoV-2.

Remdesivir inhibits the viral polymerase, which the researchers describe as the virus’s “replication engine”. The drug tricks the virus into adding faulty copies of its building blocks into RNA chains, stopping it from replicating.

The experts note that remdesivir was not as effective as antibodies against Ebola Zaire. At the time, remdesivir could only be given by intravenous injection, which limited its use. The drug is now available as a pill, called obeldesivir, which should make it much easier to administer.

Remdesivir is a broad-spectrum antiviral that attacks the polymerase (the enzyme for genetic material duplication), and that is quite conserved across different strains, so there is a chance it may have an effect against Bundibugyo.

They add that the key with any Ebola treatment is to give it early, before the virus causes major damage. The WHO was right to take the current Ebola outbreak seriously. There are likely already many more cases than have been reported. Once high numbers of cases are seen, it suggests there are likely many cases that have not yet been diagnosed. The virus is also already moving. Although most cases so far have been in one region, two have been confirmed in Uganda in people who travelled there from Congo.

Ebola is nowhere near as contagious as COVID-19 because it requires much closer contact. It is not transmitted through the air like influenza and coronaviruses, so the overall risk is very low.

The expert says the world is better prepared for coronaviruses because of the work done during the COVID-19 pandemic.

But University of Alberta experts say threats remain from relatively rare viruses such as Ebola and hantavirus, as well as more common viruses such as influenza. It is simply because viruses are able to adapt quickly, and humans are always trying to catch up.

It is important to optimise all workflows and continue developing broader-spectrum antivirals, antibodies and vaccines so there is a better chance of responding quickly to future outbreaks.