Microbiology and Parasitology: Chain of Infection

Microbiology and Parasitology

• Pathogens are substances that alter the structure or function of the nervous system.
• Neurotoxins are a type of pathogen.
• The chain of infection involves six steps: pathogen, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.

Pathogenesis

• Refers to the steps or mechanisms involved in the development of a disease.

Epidemiology

• The four periods or phases in the course of an infectious disease are incubation, prodromal, period of illness, and convalescent.
• Hyperendemic refers to a disease that is equally endemic in all age groups of a population.
• Holoendemic refers to a disease that is endemic in most of the children in a population, with the adults in the same population being less often affected.

Infections

• Septicemia is a condition in which the bloodstream contains bacteria or other toxins.
• Meningococcemia is a specific type of septicemia caused by Neisseria meningitidis.
• Airborne transmission involves particles less than or equal to 5 nanometers in size.
• Droplet transmission involves particles larger than 5 nanometers in size.

Healthcare Associated Infections (HAIs)

• UTIs, surgical site infections, lower respiratory infections, and bloodstream infections are four common types of HAIs.
• Asepsis means "without infection" and can be medical or surgical.
• Airborne infection isolation rooms have negative pressure to prevent airborne droplet nuclei from entering the corridor.
• Protective environments are under positive pressure, and air entering the room passes through HEPA filters.

Microbial Ecology and Microbial Biotechnology

• Microbial ecology is the study of interactions among organisms and their environment.
• Microbial ecology involves the study of numerous interrelationships between microorganisms and the world around them.
• Symbiosis is a close and often long-term relationship between different species.
• Mutualism is a symbiotic relationship in which both individuals benefit from the association.
• Synergism is the interaction or cooperation of two or more agents to produce a combined effect greater than the sum of their separate effects.

Indigenous Microflora of Humans

• Normal flora refers to the microbes that reside on or within the human body.
• The resident microflora of the skin consists primarily of bacteria and fungi.
• The most common bacteria of the skin are species of Staphylococcus, Micrococcus, Corynebacterium, Propionibacterium, Brevibacterium, and Acinetobacter.

Epidemiology and Public Health

• Communicable disease refers to an infectious disease that is transmissible from one human to another.
• An epidemic is a widespread outbreak of a disease affecting a large number of people.
• Reservoirs of infections can be living (animals, arthropods) or non-living (air, soil, dust, food, milk, and water).
• The five principle modes of transmission are contact, airborne, droplet, vehicular, and vectors.
• Portal of entry refers to the route by which a pathogen enters the body.

Bioterrorism

• Bioterrorism is the intentional release or dissemination of biological agents.
• The most commonly discussed pathogens in bioterrorism are Bacillus anthracis, Clostridium botulinum, Variola major (smallpox virus), and Yersinia pestis (plague).

This quiz covers the basics of microbiology and parasitology, including the chain of infection and neurotoxins. Test your knowledge of pathogens and their effects on the nervous system.