A biological characteristic that improves the chance of survival of an organism and its descendants.
Any foreign substance that when introduced into the body stimulates an immune response.
The appearance of mutations in a virus' genome as it replicates over time.
A widespread outbreak of an infectious disease where many people are infected at the same time.
The scientific theory for how groups of living things change over time.
An inherited piece of information contained in a cell's DNA. The information from each gene is used to make a unique type of protein, which has a specific function for the cell.
The scientific study of heredity. Also, the genetic constitution of an individual, group, or class.
The parts of the body that prevent and fight disease.
Any organism that can only be seen with a microscope; protozoans, bacteria, fungi, and viruses are examples of microorganisms.
A change in a gene´s structure that may be passed on to future generations.
The basic structural unit of nucleic acids (DNA or RNA).
The occurrence of a large number of cases of a disease in a short period of time.
An epidemic that affects multiple geographic areas at the same time.
Any disease-producing agent; such as, viruses, bacteria, or other microorganisms.
A group of organisms of one species, occupying a defined area and usually isolated from similar groups of the same species.
Preventive measure or medication.
Any of a group of complex organic compounds which contain carbon, hydrogen, oxygen, nitrogen and usually sulfur, the characteristic element being nitrogen; widely distributed in plants and animals.
The exchange of genetic material between two viruses inside a cell of an organism.
A host that carries a pathogen without injury to itself and serves as a source of infection for other host organisms.
RNA (ribonucleic acid)
A nucleic acid that governs protein synthesis in a cell.
A group of individuals, usually identifiable by a set of distinctive features, with a unique evolutionary history. Classically, the members of a species can interbreed only with each other to produce fertile offspring.
A substance that contains antigenic components, either weakened, dead or synthetic, from an infectious organism which is used to produce active immunity against that organism.
An organism that transmits a pathogen.
The degree or ability of a pathogenic organism to cause disease
An ultramicroscopic infectious agent that replicates itself only within cells of living hosts.