Pathogens at a Glance

Pathogens are agents that cause disease and are commonly known as bacteria, viruses, fungi or molds. They cause disease in plants and animals by impacting the physiology of the host. Although there have been advances in safeguarding against human infection by pathogens via vaccinations, antibiotics and fungicides, progress on the botanical, food and industrial side, has been more challenging.

Which Pathogens are harmful?

The most common pathogens have become household names such as Escherichia Coli (E. Coli for short), Salmonella, and different strains of Staphylococcus.

There are over 200 different pathogens that can cause disease in humans, animals and plants.

How Pathogen’s harm from a human health standpoint?

Pathogens cause infectious disease ranging from the common cold, stomach viruses, strep throat, to more severe forms of disease such as AIDS, pneumonia, H1N1 virus, malaria and Ebola. Bacteria such as E. Coli reproduce rapidly and give off toxins, damaging the tissues of the body, causing inflammation of stomach and intestinal linings, excessive salivation, vomiting, diarrhea, and abdominal pain.

How Pathogens harm from a plant health standpoint?

Plant diseases can be caused by fungi, bacteria, viruses, or nematodes. Various organisms can transport (vector) pathogens from infected to healthy plants.

Of the 1600 known bacterial species about 200 have been found to cause disease in plants. Most plant infecting bacteria are rodshaped with threadlike structures (Flagella) that propel them through liquids. Some bacteria multiply every 20 minutes. At this rate, 1 bacterium can give rise to 17 million daughter cells within 12 hours if food, moisture, and temperature are favorable.

Fungi are small, usually microscopic, plants that lack chlorophyll and conductive tissues. Unlike green plants, they do not photosynthesize their own food, so they depend on living or dead plant or animal tissue. Of the 100,000 species of fungi on earth, only about 8,000 are known to cause disease in plants. All plants can be attacked by some type of fungi. Each of the parasitic fungi can attack one or many kinds of plants. Some fungi grow and multiply by living on their host plant during their entire life cycle. Other fungi can multiply on dead organic matter as well as living on plants. Fungi reproduce mainly by means of spores. These spores are special reproductive bodies made up of one or a few cells. The spores perform the same job as seeds in higher plants. Some fungi produce up to 5 types of spores to complete a single life cycle.

Viruses are pathogenic particles that infect most higher plants and animals. Virus particles are extremely small (20 to 250 nanometers. Viruses are not cells, nor do they consist of cells. They can be seen only with an electron microscope. They cannot grow or multiply except when they are within a host cell. These particles move from one plant to another via vectors.