The remains are called fossils. Fossils are remnants of animals, plants, or microorganisms that have been solidified in the process of fossilization, where the organism is surrounded by sediment, minerals, and other solid objects which are compressed and heated around the organism over time. This forms a solid mass with the preserved organism inside, other known as a fossil.
A vaccine is used to provide active acquired immunity to the host by supplying them with a biological preparation which is often made up of attenuated organism, its associated immunogenic particle, protein, DNA, etc.
Today there are vaccines available for a wide variety of diseases however there is no preventive vaccine for listeriosis.
Listeriosis is a disease caused by <em>Listeria monocytogenes</em> and it is a very serious disease often caused due to the consumption of contaminated food.
There is unavailability of a commercially available vaccine against listeriosis although a lot of research is underway to prepare a vaccine to reduce the mortality rate.
