Question

(general microbiology class in nursing school)

Discuss how a pathogen causes an infection. Include definitions for primary pathogen, opportunistic pathogen, infection, disease (caused by a living organism), and various stages of pathogenesis. You can choose a specific organism to describe (like Orthomyxovirus and Influenza) or discuss a generalized infection.

References are greatly appreciated.

Answer 1

Pathogen causes infection. But Infection with all pathogen does not necessarily lead to disease. Infection occurs when viruses, bacteria, or other microbes enter into the body and begin to multiply. Disease occurs as a results of damage to the cells by the pathogen and signs and symptoms of an illness appear.

Primary pathogen

Primary pathogens cause disease as a result of their presence or activity within the normal, healthy host, and their intrinsic virulence.

Opportunistic pathogen

Opportunistic pathogens are organisms that can become pathogenic following a perturbation to their host (e.g., disease, wound, medication, prior infection, immunodeficiency, and ageing).

Infection disease (caused by a living organism)

Infectious diseases are disorders caused by organisms — such as bacteria, viruses, fungi or parasites. Many organisms live in and on our bodies. They're normally harmless or even helpful. But under certain conditions, some organisms may cause disease.

Various stages of pathogenesis.

The pathogenesis of a disease is the biological mechanism that leads to a diseased state.

The stages of pathogenesis include exposure, adhesion, invasion, infection, and transmission.

Generalized infection by influenza

Influenza, one of the most common infectious diseases, is a highly contagious airborne disease that occurs in seasonal epidemics and shows as an acute febrile illness with variable degrees of systemic symptoms, ranging from mild fatigue to respiratory failure and death..

The virus is inhaled or transmitted, usually via fingers, to the mucous membranes of the mouth, nose or eyes. It then travels down the respiratory tract and binds to epithelial cells lining the lung airways via specific molecules on the cell surface.

The influenza virus primarily attacks respiratory tract: the nose, throat, and the tubes to lungs. So symptoms like a runny nose, a phlegmy cough, and a sore throat will occur.

  Referances

· Pubmed.ncbi.nim.nih.gov

· Ananthanarayanan, Textbook of microbiology, Japee publishers.