WHO raises the global alert for coronavirus to the highest possible level short of pandemic

Hello Nature readers,
Today we discover that early Earth might have been almost devoid of land, learn that coronavirus infections have passed 90,000 and hear what Nobel-prizewinning chemist Frances Arnold and other senior scientists learnt from the experience of retracting a paper.

Oceanic crust from the Panorama district in the Pilbara Craton of Western Australia is a time capsule of early Earth. (Planet Observer/Universal Images Group via Getty)

Early Earth might have been a water world Early Earth might have been covered with ocean and almost devoid of land. Researchers examined the ratio of oxygen isotopes in a 3.2-billion-year-old slab of the planet’s crust that is exposed in Western Australia. High levels of oxygen-18 in the oldest rock suggest that continents (which absorb that isotope) might not have emerged until between 3 billion and 2.5 billion years ago. The Guardian | 5 min readReference: Nature Geoscience paper

COVID-19 coronavirus outbreak Authorities monitor people for coronavirus symptoms at Kraków airport in Poland. ( Beata Zawrzel/NurPhoto/Getty) Global infections pass 90,000 The number of people worldwide who have been infected with coronavirus that causes COVID-19 has passed 90,000. More than 3,000 people have died since the outbreak began in December. The vast majority of cases have occurred in China, but around 60 other places have reported infections. South Korea, Italy and Iran are fighting the largest outbreaks outside China. (Nature | Continuously updated) The World Health Organization (WHO) has raised the global alert for COVID-19 to ‘very high’ — the highest possible level short of calling it a pandemic. The assessment is based on the continued increase in cases and affected locations, and the difficulties that regions such as Iran and Italy are facing in containing the spread. “We still have a chance of containing this virus, if robust action is taken to detect cases early, isolate and care for patients and trace contacts,” said Tedros Adhanom Ghebreyesus, director-general of the WHO. (Nature | Continuously updated) The United States is falling behind on diagnosing coronavirus infections after the Centers for Disease Control and Prevention (CDC) struggled to mass-produce a working test. Flaws in the CDC’s kit were discovered only after hundreds had been shipped to state laboratories last month. (The New York Times) Read the latest coronavirus news, continuously updated on Nature.

NOTABLE QUOTABLE “China has rolled out perhaps the most ambitious, agile, and aggressive disease containment effort in history.” China’s response to COVID-19 has been effective, says a WHO report released on 28 February. (Science) Reference: WHO report

Features & opinion

What we learnt from retracting a paper “Someone I admire retracted a very important paper when I was a young scientist,” says Nobel-prizewinning chemist Frances Arnold, who retracted a paper in January. “I wanted to pay that lesson forward.” Arnold and three other senior scientists share what they learnt from the experience of retracting flawed papers. Nature Index | 4 min read

Open your lab to art When ecologist Matthias Rillig welcomed artist Karine Bonneval into his lab, he saw some benefits he had not expected. In the end, a new research question was born, which resulted in a paper listing Bonneval as a co-author. Rillig offers his advice for scientists on how to make the most of an artist-in-residence. Nature | 8 min readReference: Soil Systems paper

News & views

One gene sets the stage for toxoplasmosis Around one-third of the global human population is infected with the single-celled organism Toxoplasma gondii, which in some cases causes the incurable disease toxoplasmosis. Researchers have found a single gene that controls the conversion of the parasite into a form that chronically infects the human brain. Targeting the gene, BFD1, shows real potential for making progress in the development of drugs or vaccines, writes biochemist Eva-Maria Frickel. Nature | 6 min readReference: Cell paper

Image of the week

In a 340-litre aquarium, researchers smashed vortices of coloured fluid together to study turbulence. They discovered a cascading cycle of propagating, ever-smaller vortices — “a Russian nesting doll of disorder”. (Harvard John A. Paulson School of Engineering and Applied Sciences press release) Reference: Science Advances paper (Video courtesy of Harvard SEAS)

QUOTE OF THE DAY “The beauty of science is that all the important things are unpredictable. The optimistic view in me is that nature is designed to make the universe as interesting as possible.” Physicist Freeman Dyson, who died on Friday at the age of 96, spoke to physicist Katie Mack last year about the end of the Universe. (The New York Times)

Ecologist Solene Marion snapped this red deer with an unusual stance giving the side-eye to her camera trap in Scotland. Stand and deliver your feedback on this newsletter — please email me at briefing@nature.com. Flora Graham, senior editor, Nature Briefing