Analysis of wastewater from sewage systems has provided an early warning system for the presence of Covid-19 in communities – showing up in the water samples before people test positive. It’s also possible to identify the variants and even specific genetic mutations. Davida Smyth of Texas A&M University has been using this technique in New York and found intriguing results - forms of the virus not present in humans. The suggestion is that mutated forms may be infecting other animals, possibly those present in the sewers.

An analysis of long Covid, symptoms of fatigue, and ‘brain fog’ which occur long after initial infection, show that around a quarter of those infected develop these symptoms. Lucy Cheke of Cambridge University discusses the implications.

The war in Ukraine has highlighted the importance of the region in supplying raw materials and energy to other countries, gas, cereal crops, and fertilisers in particular. As crop scientist John Hammond from Reading University explains, the stopping of fertiliser exports from Russia, in particular, could impact food security in many countries.

And with unseasonal fires already burning in the Western US Caroline Juang of Columbia University’s Earth Observatory gives us her analysis of the driving factors in the intensification of fires year-on-year.

(Image: USA, New York, steam coming out from sewer. Credit: Westend61/Getty Images)

Presenter: Roland Pease Producer: Julian Siddle