A nurse who cared for an Ebola patient repatriated to a Madrid hospital has contracted the disease, the Spanish health ministry announced on 6 October. But the news is, unfortunately, not surprising.

US National Institute of Allergy and Infectious Disease

Although Ebola is relatively difficult to catch in the community because infection requires contact with the bodily fluids — such as blood or vomit — of an infected person, close contacts and health-care workers treating patients with Ebola have long been recognized as being most at risk of contracting the virus.

Health-care workers have already paid a heavy price in the current epidemic in west Africa: as of 1 October, the World Health Organization estimates that 382 have contracted Ebola, and 216 of them have died.

Spanish authorities will investigate how the nurse at the Carlos III hospital came to be infected, and whether there were any shortcomings in infection control — such as in the personal protective equipment supplied, training in its use or hospital hygiene. As someone who recently treated an Ebola patient, the nurse would have been considered a contact at risk of exposure to the virus, and have been monitored for any symptoms such as fever, that could signal the onset of Ebola. Such surveillance of contacts is crucial to preventing any onward spread of virus.

It’s important to remember that people with Ebola don’t become infectious until they start showing symptoms, so monitoring of contacts of an Ebola-infected patient for fever is usually considered sufficient, with them being isolated only at the first hint of illness — although some authorities may choose to quarantine high-risk contacts. Such early isolation is crucial to limit the number of people they could come into contact with.

A key question for Spanish authorities will be whether there was any delay between when the nurse first showed symptoms and when she was isolated. They will then try to trace every single person she was in contact during that period and monitor them for symptoms for 21 days, the maximum incubation period of the disease (see ‘How disease detectives are fighting Ebola’s spread‘ for an explainer of this process of ‘contact tracing’).

That contacts of the nurse might in turn become infected cannot be ruled out, but the case does not raise any major threat of an outbreak of Ebola in Europe. Risk assessments of the current outbreak have long factored in the prospect that infected people would occasionally travel from the epicentre of the epidemic in west Africa to distant unaffected areas, and that healthcare workers are among those most at risk of secondary infections.

The Spanish case raises legitimate concerns as to the preparedness of hospitals to safely treat Ebola patients, and spotlights the need for health facilities everywhere to review their own precautions and practice. But even with the best training and equipment, the infectious nature of bodily fluids that carry Ebola means that accidental infections of health-care workers treating patients with the virus will unfortunately continue.

In its latest risk assessment, the the European Centre for Disease Prevention and Control reiterated that “if a symptomatic case of [Ebola] presents in an EU Member State, secondary transmission to caregivers in the family and in healthcare facilities cannot be ruled out.” Europe’s well developed public-health services are, however, well placed to quickly stamp out any further chains of transmission using contact tracing.

The big lessons of the new Spanish case, as in the recent case of a traveller from Liberia diagnosed with Ebola in Dallas, Texas, are the same: that unless the international community acts far faster, and on a far larger scale, to tackle Ebola at its source in west Africa, exported cases and the repatriation of sick health-care workers will continue — and family, and health-care workers caring for them, will continue to become infected with Ebola.