The number of cases of Covid -19 infections in Brazil and deaths related to the pandemic may be much higher than official figures show. Testing of the living is not widespread and there are few resources for analysing the potential role of the virus as a cause of death. Virologist Fernando Spiliki gives us his bleak assessment.

A remarkable study from South Africa shows just how easily the virus can spread around a hospital, with a single infected person infecting many. However the route of infection is not necessarily direct person to person transmission says investigator Richard Lessells from the University of KwaZulu Natal. And from London a study in a hospital with many Covid patients at the height of the pandemic supports the South African findings; Researchers found viral particles on surfaces and in the air says Professor Wendy Barclay from Imperial College.

An early warning system for outbreaks of the virus or second waves may come from analysis of sewage, Jordan Peccia from Yale University analysed waste from his local sewage treatment works and found peaks in concentrations of the virus in the sludge occurred a few days before increases in hospital admissions.

(Image: Supporters of Brazilian President Jair Bolsonaro wear face masks as they demonstrate against quarantine and social distancing measures imposed by governors and mayors to combat the new coronavirus outbreak and demand military intervention.

Also this week, The kids take over. Our younger listeners are as curious as their parents, it seems, so presenter Marnie Chesterton seeks out the finest minds and attempts to answer a raft of their science questions, including why can’t you tickle yourself? Why don’t our eyebrows grow as long as the hair on our heads?

Not content with humankind, these whizz kids have been pondering deeply about other animals. Ava, 9, from the UK wants to know if any other animals kill for fun, like some humans do.

Not limited by planet Earth, these little thinkers have been contemplating even weightier questions. Joshua, 13, from Kenya wonders if our Solar System rotates around anything. And Seattle-based Michael, 10, puzzles over what would happen if a black hole collided with a wormhole.

These and other mysteries are uncovered by Marnie and her experts.

Credit: SERGIO LIMA/AFP via Getty Images)