Pathogens in Animals and Plants

By: Steven Shanks Jessica Wright Ashley Berg

What is a Pathogen?A Pathogen is an infectious agent, or more

commonly germ, a biological agent that causes disease to its host.

Virus Diseases in AnimalsSome common diseases in animals include

bird flu, rabies, and anthrax. There are many common ways to treat these

diseases in animals and the most common way is Vaccines.

Vaccines are simply harmless variants of pathogenic microbes that stimulate the immune system to put up a defense against an attacking disease.

Emerging VirusesThree processes contribute to the emergence

of viral diseases. 1.First, the mutation of existing viruses is a

major source of these new diseases. 2.Another source of new viral diseases is the

spread of existing viruses from one host species to another.

3.Finally, the dissemination of a viral disease from a small, isolated population can lead to widespread epidemics.

Emerging Virus pictures

Viral Diseases in PlantsThere are currently more than 2,000 different

types of viral diseases in plants that are known to the world. Plant viral diseases spread by two major routes.

In the first route, called horizontal transmission, a plant is infected from an external source of the virus.

The other route of viral infection is vertical transmission, in which a plant inherits a viral infection from a parent.

Viral infections of plants

Viral infection of plants.  Infection with particular viruses causes “breaking” or streaking of tulip flower color (top), irregular brown patches on tomatoes (left center), and black blotching on squash (bottom).

Viroids and Prions: The Simplest Infectious Agents

Viroids. These are circular RNA molecules, only several hundred nucleotides long, that infect plants.

Prions. Infectious proteins that appear to cause a number of degenerative brain diseases in animals.