What can Roman outbreaks of malaria teach us about Covid?

When Covid-19 first appeared, its similarity to Sars made some assume it could not mount a pandemic; others that it would be infectious, but mild. Assumptions with unhappy consequences are nothing new: some can last millennia.

Take the West’s understanding of malaria. This deadly fever, widespread across the ancient world and mentioned in Homer, is caused by mosquitoes carrying the malaria parasite. But the ancient view was that ‘bad air’ (mal’aria, from the Italian) was the cause, reasonably enough, since the disease was clearly associated with swamps.

Roman encyclopaedist Varro nearly solved it, arguing that ‘certain small animals breed there, invisible but causing troublesome diseases by entering through mouth or nose’. But Romans did not make the link with mosquitoes because not all mosquitoes carry the parasite — so some swamps were harmless. Further, as Pliny the Elder noted, Romans used to noxious conditions could work near them quite happily; but Romans had no concept of immunity. To keep the irritants off, at least some used wormwood and nets.

Having failed to drain the swamps, the Romans, who knew this disease flourished only at lower levels, socially distanced from them. Cato advised building farms in ‘healthy’ places, away from swampy land, and the architect Vitruvius suggested locating villas on high ground (as the elite did on the hills of Rome). But this option was not open to plebs. So they looked to the gods, especially Febris (‘Fever’), who long outlasted antiquity and even had a shrine in the Vatican. Others preferred magic: write abracadabra, line below line, each time removing the final letter, until there is a single ‘a’ at the bottom of the cone. Hang round the neck with a linen thread. (5G theorists might like to try it.