The Pirbright Institute has revealed that on June 14, 2019, it destroyed the largest remaining stock of rinderpest virus on the face of the Earth. The destruction of one of a handful of laboratory samples of the deadly cattle virus was carried out under a program by the World Organisation for Animal Health (OIE) and the Food and Agriculture Organisation of the United Nations (FAO) to prevent any future outbreaks of the disease by eliminating it entirely.

It may seem odd in our environmentally conscious times, but there are some organisms that it's generally agreed should be hounded to extinction. One of these is the smallpox virus, which was eradicated in the wild after an aggressive campaign that took over 200 years. Today, the virus exists in only two laboratories in the United States and Russia, though there is consistent pressure to have even those destroyed.

Now it's the turn of rinderpest virus. Less well known to the general public, rinderpest, also known as cattle plague or steppe murrain, is a disease that, though it does not attack humans, has caused incredible death and suffering by wiping out millions of cattle and similar species, sparking major famines and economic collapse.

Eradication campaigns of this most deadly of cattle diseases started in the early 20th century and eventually pushed it out of every place on Earth, saving Africa alone US$920 million a year. In 2011, rinderpest was declared eradicated, but Pirbright says that, at that time, there were samples of the virus in 40 laboratories in 36 countries.

"The biggest risk of rinderpest re-appearing comes from an accidental escape from a laboratory, something that might be possible in the future if stocks are kept, even though no one is working on the virus." says Michael Baron, Honorary Fellow at Pirbright and rinderpest expert for the OIE.

To prevent this, the FAO and OIE started a campaign to move all known samples to special high containment laboratories called Rinderpest Holding Facilities (RHF), of which The Pirbright Institute was the largest. This was followed by a "Sequence and Destroy" program, where the rinderpest virus was studied to produce a complete DNA sequence, similar to the human genome project, which was followed by destroying the samples.

In this way, the genetic data could be used to create vaccines if an outbreak did occur from some unknown source. It would also act as an example to other laboratories to persuade them to do the same.

"This is a culmination of years of work by Pirbright scientists and our international collaborators; over 2,500 virus samples from as far back as the 1950s have been destroyed." says Carrie Batten, Chair for the Rinderpest Holding Facility Network and leader of the Non-Vesicular Disease Reference Laboratory at Pirbright.

The last Pirbright samples were destroyed in the Plowright Building, named after Walter Plowright, who developed the rinderpest vaccine that eradicated the disease.