First, one takes samples (blood, sputum, secretions) from many people (e.g. 500) with symptoms which are unique and specific enough to characterize an illness.

Without mixing these samples with ANY tissue or products that also contain genetic material,

the virologist macerates, filters and ultracentrifuges i.e. purifies the specimen.

This common virology technique, done for decades to isolate bacteriophages 1 and so-called giant viruses in every virology lab, then allows the virologist to demonstrate with electron microscopy thousands of identically sized and shaped particles.

These particles are the isolated and purified virus.

These identical particles are then checked for uniformity by physical and/or microscopic techniques.

Once the purity is determined, the particles may be further characterized.

This would include examining the structure, morphology, and chemical composition of the particles.

Next, their genetic makeup is characterized by extracting the genetic material directly from the purified particles and using genetic-sequencing techniques, such as Sanger sequencing, that have also been around for decades.

Then one does an analysis to confirm that these uniform particles are exogenous (outside) in origin as a virus is conceptualized to be, and not the normal breakdown products of dead and dying tissues.2

(As of May 2020, we know that virologists have no way to determine whether the particles they’re seeing are viruses or just normal break-down products of dead and dying tissues.) 3

If we have come this far then we have fully isolated, characterized, and genetically sequenced an exogenous virus particle.

However, we still have to show it is causally related to a disease.

However, we still have to show it is causally related to a disease.

This is carried out by exposing a group of healthy subjects (animals are usually used) to this isolated, purified virus in the manner in which the disease is thought to be transmitted.

If the animals get sick with the same disease, as confirmed by clinical and autopsy findings, one has now shown that the virus actually causes a disease.

This demonstrates infectivity and transmission of an infectious agent.