Cattle plague was a lethal disease of bovines cause by the rinderpest virus, an agent closely related to measles. It came to Britain from Europe in the mid 1860s and killed at least 420,000 cows. Rinderpest is not a coronavirus. Its R number is probably three times greater than that of Covid-19, and its mortality rate is much higher. But as a model it still has relevance to contemporary events.
On 18 April 1947 in a cage on a tree platform in the Zika Forest in Uganda, rhesus monkey number 766 developed a fever. Its serum was inoculated into the brains of mice. They fell ill. Zika virus had been discovered. The sentinel monkey researchers were the virologist George Dick and the entomologist Alexander Haddow, based at the Rockefeller Foundation Yellow Fever Laboratories in Entebbe. Haddow went on to build a 120-foot steel tower in the forest to study high-flying mosquitoes and their viruses. The best time and place to find Zika virus was in the evening, 80 to 100 feet above the forest floor.
With two million cases in the UK every year, norovirus exceeds all other causes of diarrhoea and vomiting by many orders of magnitude. If a malevolent person had set out to create it as the nastiest virus known, their only disappointment would be a lethality failure; the vast majority of victims get better after two or three days without specific treatment. Just as well, because there isn’t one.
A coronavirus particle has spikes on its surface with knobs on the ends, making it look a bit like the sun and its corona. Hence the family name. Human ones were first seen in the 1960s by the electron microscopist June Almeida, in collaborative common cold research with the virologist David Tyrrell. Growing the viruses was very difficult. Almeida and Tyrell were enthusiasts for organ culture (I am reminded of it daily; I worked with June and have a scar on my forearm where skin was taken in a vain attempt to grow wart viruses). Bits of tissue kept alive in test tubes were infected with sneezings from common cold sufferers. It turned out that a quarter of colds are caused by coronaviruses.
The influenza season draws to a close. But the virus isn’t going quietly. Monday 2 April started early for me with an interview on the Today programme about the sensible decision by the US National Science Advisory Board for Biosecurity to give up trying to censor papers describing the enhancement of bird flu infectivity in ferrets. I covered the same story for Good Morning Scotland. The benefits of knowing about potentially nasty mutations before they take us by surprise far outweigh any risks from al-Qaida virologists.
Lambing is just starting. But the pictures on TV in the last few days have been of stillborns, and of newborns with bent legs, seized-up joints and crooked necks. Their mothers had been infected during pregnancy with the Schmallenberg virus, called after the German town where it was discovered last year. It belongs to a family – the bunyaviruses – that are mostly spread by insect bites.