How Geneva is preparing for the next viral outbreak

Mpox, hantavirus, Ebola: when these viruses emerge, the Geneva Centre for Viral Emerging Diseases at HUG and UNIGE plays a key role in diagnosis and clinical response. Founded in the wake of the 2014 Ebola epidemic, the Centre is celebrating its tenth anniversary as a new outbreak alarms an entire continent.

The Geneva Centre for Emerging Viral Diseases brings together expertise that is unique in Switzerland. Image: HUG

A virus, when you get down to it, is a remarkably simple thing: a strand of RNA or DNA wrapped in a protein coat. Yet when it appears in an unexpected form, or in a region of the world that has never encountered it, this tiny assembly can endanger entire populations and put hospitals, health authorities and scientific networks on high alert. It is precisely to anticipate such moments that the HUG/UNIGE Geneva Centre for Viral Emerging Diseases exists. "An emerging virus is either a completely new virus — like SARS-CoV-2 was at the time — or a known virus detected for the first time in a region where it was not previously endemic," explains Professor Isabella Eckerle, a physician at the HUG, a researcher in the UNIGE Faculty of Medicine, and the Centre’s Director. Mpox in Europe, Zika in Brazil, hantavirus aboard a cruise ship, or Ebola Bundibugyo now spreading in the Democratic Republic of Congo (DRC) and Uganda: every time, the question is the same — can we rapidly identify what is circulating to take the right measures?

A centre that watches with quiet vigilance

Drawing on long-standing expertise and reference laboratories established in the early 2000s, the Centre was formally created in 2016 in the aftermath of the Ebola epidemic that struck West Africa in 2014. The aim was to bring together, in Geneva, the clinical, diagnostic and scientific skills — alongside the international connections — needed to respond to emerging viruses. "We are one of only two centres in Switzerland capable of treating patients with highly pathogenic viruses, such as Ebola," says Isabella Eckerle. In practice, this means trained physicians, trained nurses, regularly rehearsed procedures, protective equipment, and a high-security laboratory capable of operating around the clock whenever a case is suspected. To meet these requirements, the Centre is affiliated with several virology laboratories and clinical services, as well as a number of national and international reference laboratories.

Above all, however, the cornerstone of this preparedness is diagnosis. When a virus appears, it must be possible to identify part of its genetic material. The Centre relies in particular on PCR — a technique that amplifies fragments of viral RNA or DNA until they can be detected and interpreted. But the PCR test must be aimed at the right target. "For several rare viruses, no commercial test exists. We develop our own," explains the virologist. "That means we know exactly which sequences they recognise, and we can adapt them if the virus changes."
Much of this work takes place far from the spotlight, during quiet periods, sometimes to establish screening protocols that will almost never be used. But that is precisely what makes it possible to be ready when a virus does emerge.

When diagnosis changes everything

Recent events have illustrated this clearly. In the spring of 2026, a cluster of hantavirus — extremely rare in this part of the world — was identified among tourists and crew members aboard the cruise ship MV Hondius. A Swiss traveller who had disembarked before the general alert arrived at Zurich Hospital with symptoms. He had stayed aboard the vessel in question. His sample was sent directly to Geneva. "Thanks to our PCR test, we were able to confirm very quickly that it was indeed the Andes virus," recalls Isabella Eckerle. A crucial detail: of all the hantaviruses transmitted to humans by rodents, the Andes virus is the only one capable of spreading from human to human.

The Centre, working in collaboration with the virology laboratory in Zurich, rapidly sequenced the virus. The sample arrived on a Tuesday. By Friday, a report had been published internationally. "We were able to show the world that this was not a new virus, but a known strain, closely related to those already described in South America," the researcher notes. In a context where rumours can spread faster than data, this precision is reassuring, helps orient other laboratories, and sheds light on the virus's characteristics so that public health measures can be calibrated accordingly.

This articulation between cutting-edge laboratory research and fieldwork is at the heart of the Geneva model. The Centre also collaborates with the WHO on epidemic and pandemic diseases, contributes to training, makes protocols available, and is embedded in an indispensable international network. "This work cannot be done at the national level alone," says Isabella Eckerle. "To stay current, you need to exchange with international partners."

From surveillance to the university laboratory

The link with UNIGE is expressed in particular through the translational research conducted by Isabella Eckerle. Her group studies emerging zoonotic viruses (transmitted from wildlife) such as coronaviruses and other respiratory viruses. The goal is to better understand how a virus behaves in human cells and how diagnostic tests respond to new variants.
"You cannot always predict the behaviour of a virus from its genetic sequence," she explains. Her team therefore works with cultured human-derived cells — from the respiratory tract or the placenta, for instance — to observe what a virus actually does at the cellular level. Does it trigger a strong immune response? Does it evade antibodies? Is it resistant to certain treatments? Do commercial tests detect it? Questions that may seem highly theoretical can quickly become critical during an outbreak.

Ebola: a brutal reminder

The current Ebola Bundibugyo epidemic in the DRC is a reminder of just how important anticipation and diagnosis are. This strain is rarer than the Ebola Zaire virus that drove the major 2014 epidemic, yet some of the rapid tests deployed in the field were primarily designed to detect the latter. "Patients appeared clinically to have Ebola, but the tests said otherwise. This may have contributed to delayed detection, and therefore to the spread of the epidemic," explains Isabella Eckerle.

In her view, this episode illustrates a recurring difficulty. Simple, closed, rapid and robust tools are invaluable in countries with limited health infrastructure, but they do not always detect every strain. Conversely, conventional laboratories are costly and require greater training and infrastructure — but they offer far greater capacity for adaptation and analysis. This is precisely why the Centre is committed to contributing to local capacity-building, with the support of the WHO and NGOs.

In Geneva, the Centre remains on standby. Its tests can detect the different strains of Ebola. The feared scenario remains unlikely for Switzerland — but it has been planned for. One cannot rule out that a medical repatriation, an international organisation staff member exposed in the field, or a traveller returning home unknowingly infected might one day bring this grim virus to our shores.

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