Liam Shaw

A hantavirus outbreak is extremely unexpected. Part of the confusion in press coverage has arisen from the messiness of viral classification. Although virologists do their best to categorise viruses into the traditional hierarchies of taxonomy – species, genus, family – the results are rarely satisfactory. Hantaviruses are a fairly diverse group of related viruses containing at least twenty species, only some of which can infect humans, and causing quite different diseases when they do. The natural hosts for all those viruses are thought to be rodents. After the passengers on the Hondius were informed in early May that the authorities suspected hantavirus, at least one hoped that it meant the ship was rat-infested; the alternative was that the outbreak was of the Andes virus, the only hantavirus species believed to be capable of human-to-human transmission.

The first vaccines a two-month-old child gets in England offer protection against three species of virus and five bacteria. Since 2015, they have included Neisseria meningitidis group B, the bacterium involved in the recent meningitis outbreak in Kent in which two people have died. The first vaccine against bacteria was created by Louis Pasteur in 1879. It was a live attenuated vaccine for chicken cholera, meaning it involved weakened forms of the bacteria that didn’t cause serious disease. While that approach is still often used for viruses, modern vaccine development for bacteria has largely moved away from live attenuated forms. Ensuring that a bacterium is reliably weakened is a difficult problem because bacteria are complicated: SARS-CoV-2 has only eleven genes; N. meningitidis has about two thousand.

Chimpanzees, New Caledonian crows – and now cows. The list of animals that use tools grew a little longer this week, with a paper in Current Biology reporting that an Austrian cow called Veronika uses a broom to scratch herself. Appealing to tool use as a defining feature of humanity has always been a shaky argument, though a curiously persistent one.

Streptomycetes are soil bacteria that could easily be mistaken for fungi, their cells snaking through the earth in long threads that resemble mycelial networks. To propagate when their survival is threatened, they break through the earth’s surface and then cannibalise themselves, using their last resources to build aerial platforms that release spores into the atmosphere to be carried away on the wind. Streptomycetes also produce a bonanza of antibiotics.