pathogen
Quick Summary
A pathogen is a microorganism that causes disease. These disease-causing agents can include viruses, bacteria, fungi, and parasites. While many microorganisms are harmless or even beneficial, pathogens have specific properties that allow them to infect hosts and cause illness.1234
The study of how pathogens cause disease is called pathogenesis. This involves understanding the pathogen's virulence, or its capacity to establish an infection, and how it interacts with the host's biology and immune system. Pathogens can spread through various means, such as airborne transmission, direct or indirect contact, or vectors like insects. The outcome of an infection depends on both the pathogen's characteristics and the host's resistance.15234
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infectious diseaseImmune response to infectionWhen a pathogenic (disease-causing) microorganism invades the body for the first time, the clinical (observable) response may range from nothing at all, through various degrees of nonspecific reactions, to specific infectious disease. Immunologically, however, there is always a response, the purpose of which is defense. If the…
Read MoreWhen a pathogenic (disease-causing) microorganism invades the body for the first time, the clinical (observable) response may range from nothing at all, through various degrees of nonspecific reactions, to specific infectious disease. Immunologically, however, there is always a response, the purpose of which is defense. If the…
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human diseaseInfectious agents…and cause disease are termed pathogenic. Streptococcus viridans bacteria, for example, are found in the throats of more than 90 percent of healthy persons. In this area they are not considered pathogenic. The same organism cultured from the bloodstream, however, is highly pathogenic and usually indicates the presence of the…
Read More…and cause disease are termed pathogenic. Streptococcus viridans bacteria, for example, are found in the throats of more than 90 percent of healthy persons. In this area they are not considered pathogenic. The same organism cultured from the bloodstream, however, is highly pathogenic and usually indicates the presence of the…
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bacteriaBacteria in medicine…a host and are called pathogens, or disease producers. Some pathogens act at specific parts of the body, such as meningococcal bacteria (Neisseria meningitidis), which invade and irritate the meninges, the membranes surrounding the brain and spinal cord; the diphtheria bacterium (Corynebacterium diphtheriae), which initially infects the
Read More…a host and are called pathogens, or disease producers. Some pathogens act at specific parts of the body, such as meningococcal bacteria (Neisseria meningitidis), which invade and irritate the meninges, the membranes surrounding the brain and spinal cord; the diphtheria bacterium (Corynebacterium diphtheriae), which initially infects the
Read More- bacteriaNutritional requirements
…way is particularly important to pathogenic (disease-causing) bacteria, which must compete with their host for iron. In anaerobic environments, iron can exist in the more-soluble ferrous state and is readily available to bacteria.
Read More…way is particularly important to pathogenic (disease-causing) bacteria, which must compete with their host for iron. In anaerobic environments, iron can exist in the more-soluble ferrous state and is readily available to bacteria.
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- animal diseaseInfectious and noninfectious diseases
Many pathogens (e.g., the bacterium that causes anthrax) are able to live outside the animal’s body until conditions occur that are favourable for entering and infecting it. Pathogens enter the body in various ways—by penetrating the skin or an eye, by being eaten with food, or…
Read MoreMany pathogens (e.g., the bacterium that causes anthrax) are able to live outside the animal’s body until conditions occur that are favourable for entering and infecting it. Pathogens enter the body in various ways—by penetrating the skin or an eye, by being eaten with food, or…
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plant diseasePathogenesis and saprogenesisPathogenesis is the stage of disease in which the pathogen is in intimate association with living host tissue. Three fairly distinct stages are involved:
Read MorePathogenesis is the stage of disease in which the pathogen is in intimate association with living host tissue. Three fairly distinct stages are involved:
Read More- plant diseaseInfectious disease-causing agents
…as previously mentioned, are called pathogens and can be grouped as follows: viruses and viroids, bacteria (including mycoplasmas and spiroplasmas, collectively referred to as mycoplasma-like organisms [MLOs]), fungi, nematodes, and parasitic seed plants.
Read More…as previously mentioned, are called pathogens and can be grouped as follows: viruses and viroids, bacteria (including mycoplasmas and spiroplasmas, collectively referred to as mycoplasma-like organisms [MLOs]), fungi, nematodes, and parasitic seed plants.
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