The death of a scientist in Russia’s Siberian region of Irkutsk has revived concerns about plague, but health authorities say there is currently no evidence of an outbreak or sustained transmission in Europe.

The woman died from pneumonia of unknown origin, prompting speculation that she could have contracted pneumonic plague. Russian authorities have said no plague cases have been confirmed in the region, while tests conducted on people who had contact with the woman were negative.

The World Health Organization has asked Russia for additional information about the incident and offered assistance to local health authorities.

Plague is caused by the bacterium Yersinia pestis, which remains present in wild animal populations in parts of the world. It is commonly associated with rodents and the fleas that live on them. People can become infected through bites from infected fleas, contact with tissues or bodily fluids from infected animals, or respiratory particles from people suffering from pneumonic plague.

For Spain and most of Europe, however, the current risk is considered very low. The European Centre for Disease Prevention and Control says routine transmission has not been recorded in Europe for more than five decades.

That does not mean the bacterium has disappeared. Its continued presence in animal reservoirs means isolated human infections remain possible, particularly in areas where infected wildlife and fleas are found.

Spain has maintained epidemiological surveillance despite the absence of locally acquired cases for decades. In April 2026, its Public Health Commission updated the national plague protocol, including case definitions, epidemiological information and procedures for investigating suspected infections.

European authorities have also been monitoring the Siberian incident. The European Union discussed the case at a Health Security Committee meeting on October 7, while the ECDC said there was no evidence of secondary cases or sustained person-to-person transmission.

The WHO has assessed the risk to the European region as very low.

Plague continues to occur in parts of Africa, Asia and the Americas. According to the WHO, most reported human cases between 2019 and 2025 were concentrated in Madagascar and the Democratic Republic of the Congo. Madagascar records bubonic plague cases during its annual epidemic season, generally from September to April. In the United States, about seven human cases are reported each year, mainly in rural areas of western states.

The disease can occur in bubonic, pneumonic or septicaemic forms. Bubonic plague usually causes fever and painful swollen lymph nodes after an infected flea bite. Pneumonic plague affects the lungs and can spread between people through respiratory particles. Septicaemic plague occurs when the infection enters the bloodstream.

Modern antibiotics can successfully treat plague, but early diagnosis is critical. Health surveillance, rapid identification and treatment remain important in preventing isolated infections from developing into wider outbreaks.

Scientists Karl Deisseroth, Peter Hegemann and Georg Nagel have been awarded the 2026 Nobel Prize in Physiology or Medicine for their work on light-gated ion channels and optogenetics, a technique that has transformed the study of the brain.

The Nobel Assembly at Karolinska Institutet announced the award on Monday, describing the work as laying the foundation for a new era in neuroscience.

Optogenetics allows researchers to control selected cells using light, effectively providing a remote switch that can turn specific cells on or off. The technique has enabled scientists to investigate how individual neurons and neural circuits influence behaviour in living animals.

The origins of the discovery date back to Hegemann’s research more than three decades ago. While studying the single-celled alga Chlamydomonas, which moves towards light, he sought to understand how the organism detects changes in illumination.

Hegemann focused on the alga’s eyespot, a small light-sensing structure on its surface. His research and subsequent experiments identified light-sensitive proteins known as channelrhodopsins.

Hegemann later worked with Nagel at the Max Planck Institute for Biophysics in Frankfurt. The researchers inserted genes from the algae into frog egg cells and human kidney cells, demonstrating that channelrhodopsin functions as a light-controlled ion channel.

When exposed to blue light, the channel can open within about 0.2 milliseconds. Positively charged ions then enter the cell, generating an electrical signal.

Deisseroth later adapted the discovery for neuroscience. He introduced the channelrhodopsin gene into rat nerve cells and showed that blue light could activate the cells and trigger nerve signals.

He subsequently used the technique in the brains of living mice, demonstrating that researchers could control specific groups of neurons with light. Experiments showed that stimulating selected neural circuits could produce physical responses, including movements of a mouse’s whiskers, or cause sleeping animals to wake.

The method was named optogenetics in 2006 and has since become an important research tool in neuroscience.

Researchers now use it to establish direct links between neural activity and behaviour. By activating or silencing particular groups of cells, scientists can study circuits associated with fear, anxiety, reward, pain, thirst, attention and aggression.

The technique has also been used in research into conditions including depression, schizophrenia, anxiety, Alzheimer’s disease, Parkinson’s disease and epilepsy.

Per Svenningsson, chair of the Nobel Committee for Physiology or Medicine, said the discovery provides opportunities to map the brain in ways researchers could previously only imagine.

Optogenetics has also moved beyond laboratory research. Scientists are testing its potential as a treatment for retinitis pigmentosa, a genetic disorder that causes blindness through the loss of light-sensitive retinal cells.

In experimental treatments, researchers introduce genes encoding light-sensitive proteins into surviving retinal cells. In some trials, patients using specialised light-emitting goggles have been able to regain partial vision and detect high-contrast objects.

The Nobel award recognises a discovery that has given researchers an unprecedented way to investigate the relationship between brain cells, neural circuits and behaviour.

About 1.3 billion people worldwide live with migraine, making it one of the most common neurological disorders and a major cause of disability, while many patients continue to go without a formal diagnosis or adequate medical care.

In Portugal, migraine is estimated to affect around two million people. Research by The Work Foundation, involving researchers from Lancaster University, found that about 24% of women and 13% of men in the country experience migraines.

Women are particularly affected by the condition, which can interfere with work, education and daily activities. A recent study by the European Migraine & Headache Alliance found that 92% of women with migraine in Portugal reported that the condition had prevented them from working, studying or carrying out normal activities for at least one day.

Migraine attacks can involve more than severe headaches. Patients may experience nausea and vomiting, sensitivity to light, sounds and smells, difficulty concentrating and slowed thinking.

Despite the scale of the problem, migraine remains underdiagnosed. A national consensus published in 2025 estimated that about 40% of people experiencing headaches in Portugal do not receive medical follow-up. Among those who do seek care, more than half use private healthcare services.

The same document estimated that about 1.5 million people in Portugal could benefit from medical follow-up for headaches, with around 90% potentially being treated through primary healthcare.

The European Migraine & Headache Alliance study found that 42% of women with symptoms consistent with migraine had never received a medical diagnosis. It also found that 33.6% of people with migraine had never consulted a doctor, while 72.4% relied on self-medication.

“These figures confirm that migraine continues to be underestimated and that access to appropriate treatment is still a challenge for many people in our country,” said Isabel Pireza, chair of the General Assembly of MiGRA Portugal, the Portuguese Association of Migraine and Headache Patients.

The condition can also have significant consequences in the workplace. Research among employees of Portuguese companies found episodes of absenteeism and reduced productivity during attacks. Among workers with headache-related conditions who said they completed less than half of the work planned during an episode, 29% had migraine.

Filipe Palavra, president of the Portuguese Headache Society, said migraine could affect family, social, educational and professional life beyond its most recognised symptom of headache.

He said recognising symptoms and obtaining an accurate diagnosis were important for helping patients receive appropriate treatment and improve their quality of life.

MiGRA Portugal said many people continue to regard persistent migraine pain as something they simply have to endure. The organisation is urging people experiencing recurring symptoms to seek medical advice rather than relying solely on self-medication.