CNN tells us Longevity lies in genes, and that scientists are looking for specific genes that confer extremely long life.
Equivalently, they should be looking for viruses that confer extremely long life.
Viruses are packages of portable genetic material that can cause a wide range of changes in infected organisms. We focus on -- and almost exclusively look for -- the bad, but since reading a David Brin short story ("The Giving Plague") 8 years ago, it has seemed perfectly natural to me that there should be subtly beneficial contagions all around us as well.
(I suggest that once a group of viruses that have net-beneficial effects on health are discovered, they be christened 'saluviruses' -- from the latin 'salus' for health. As of this moment, 'saluvirus' and 'saluviruses' return no hits on Google. They would be part of a larger group of long-term residents of the human body called commensal flora.)
Who knows? It may turn out that "infectious" optimism really is!