Primary pathogen

Examples of Primary pathogen in the following topics:

• Extent of Host Involvement

  • Clinicians therefore classify infectious microorganisms or microbes according to the status of host defenses - either as primary pathogens or as opportunistic pathogens.
  • Primary pathogens cause disease as a result of their presence or activity within the normal, healthy host, and their intrinsic virulence is, in part, a necessary consequence of their need to reproduce and spread.
  • Many of the most common primary pathogens of humans only infect humans; however many serious diseases are caused by organisms acquired from the environment or which infect non-human hosts.
  • Primary pathogens may also cause more severe disease in a host with depressed resistance than would normally occur in an immunosufficient host.
  • Differentiate between primary and opportunistic pathogens in regards to host involvement

• The Diagnostic Scheme

  • Infectious disease results from the interplay between those few pathogens and the defenses of the hosts they infect.
  • The appearance and severity of disease resulting from any pathogen depends upon the ability of that pathogen to damage the host as well as the ability of the host to resist the pathogen.
  • Clinicians therefore classify infectious microorganisms or microbes according to the status of host defenses - either as primary pathogens or as opportunistic pathogens.
  • Culture allows identification of infectious organisms by examining their microscopic features, by detecting the presence of substances produced by pathogens, and by directly identifying an organism by its genotype.

• Overview of Human-Microbial Reactions

  • Human-microbial interactions can be commensal or mutualistic, as with many types of gut flora, or harmful, as with pathogenic bacteria.
  • Skin flora are usually non-pathogenic and either commensal or mutualistic.
  • Infectious disease results from the interplay between those few pathogens and the defenses of the hosts they infect.
  • Primary pathogens cause disease as a result of their presence or activity within the normal, healthy host.
  • The success of any pathogen depends on its ability to elude host immune responses.

• Natural Active Immunity

  • Naturally acquired active immunity occurs when a person is exposed to a live pathogen, develops the disease, and then develops immunity.
  • Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response.
  • Once a microbe penetrates the body's skin, mucous membranes, or other primary defenses, it interacts with the immune system.
  • The adaptive immune response generated against the pathogen takes days or weeks to develop but may be long-lasting, or even lifelong.
  • The principle behind immunization is to introduce an antigen, derived from a disease-causing organism, that stimulates the immune system to develop protective immunity against that organism, but which does not itself cause the pathogenic effects of that organism.

• Ecology, Epidemiology, and Evolution of Pathogens

  • Pathogens have evolved to adapt to their environment and their host in order to survive.
  • If a pathogen does not have this, it will likely become extinct.
  • In the case of plant pathogens, it is also their ability to survive between growing seasons.
  • For example, peanut clump virus can survive in the spores of its fungal vector until a new growing season begins and it can proceed to infect its primary host again.
  • Diseases can emerge when existing parasites become pathogenic or when new pathogenic parasites enter a new host.

• Primary and Secondary Antibody Responses

  • Pathogens can rapidly evolve and adapt to avoid detection and neutralization by the immune system.
  • As a result, multiple defense mechanisms have also evolved to recognize and neutralize pathogens .
  • Adaptive (or acquired) immunity creates immunological memory after an initial response to a specific pathogen, leading to an enhanced response to subsequent encounters with that same pathogen.
  • When B cells and T cells are first activated by a pathogen, memory B-cells and T- cells develop.
  • Throughout the lifetime of an animal these memory cells will "remember" each specific pathogen encountered, and are able to mount a strong response if the pathogen is detected again.

• Primary Immunodeficiency Diseases

  • The precise symptoms of a primary immunodeficiency depend on the type of defect.
  • These proteins, generated by plasma cells, normally bind to pathogens, targeting them for destruction.
  • Phagocytes are the cells that engulf and ingest pathogens (phagocytosis), and destroy them with chemicals.
  • Reduction of exposure to pathogens may be recommended, and in many situations prophylactic antibiotics may be advised.
  • Describe primary immunodeficiency disorders and explain what treatment options are available

• Primary and Secondary Metabolites

  • Pathogenic bacteria are capable of exhibiting various types of metabolism.
  • Metabolites can be categorized into both primary and secondary metabolites.
  • Primary metabolites are involved in growth, development, and reproduction of the organism.
  • Examples of primary metabolites include alcohols such as ethanol, lactic acid, and certain amino acids.
  • Another example of a primary metabolite commonly used in industrial microbiology includes citric acid.

• Cells and Organs of the Immune System

  • The immune system includes primary lymphoid organs, secondary lymphatic tissues and various cells in the innate and adaptive immune systems.
  • The red bone marrow is a key element of the lymphatic system, being one of the primary lymphoid organs that generate lymphocytes from immature hematopoietic progenitor cells.
  • Bone marrow and thymus constitute the primary lymphoid tissues involved in the production and early selection of lymphocytes.
  • Neutrophils and macrophages are phagocytes that travel throughout the body in pursuit of invading pathogens.
  • These cells have no cytotoxic activity and do not kill infected cells or clear pathogens directly.

• Making Memory B Cells

  • Memory B cells are a B cell sub-type that are formed following primary infection.
  • Memory B cells are a B cell sub-type that are formed following a primary infection .
  • In the wake of the first (primary response) infection involving a particular antigen, the responding naïve cells (ones which have never been exposed to the antigen) proliferate to produce a colony of cells.
  • B lymphocytes are the cells of the immune system that make antibodies to invading pathogens like viruses.
  • They form memory cells that remember the same pathogen for faster antibody production in future infections.