9 topics with a brief review: definitions, key facts, and classroom questions.
The section "Doctrine of Infection" is a fundamental basis of microbiology that links the properties of the causative agent with the host macroorganism's response. Here we examine how host reactivity factors and environmental conditions determine the development, periods, and outcomes of an infectious disease. Special attention is paid to non-cellular forms of life: mechanisms of viral pathogenicity and types of viral infection.
Infection does not exist in a vacuum, so an important part of the section is devoted to the population level: the epidemic process and the ecological and epidemiological classification. You will learn how pathogens circulate in nature and society, and which diseases are classified into the strict group of especially dangerous and quarantine infections (EDIs).
What are the most frequent exam questions? Instructors traditionally focus on terminology (it is important to clearly distinguish superinfection from reinfection, and relapse from exacerbation), the characterization of periods of an infectious disease, and the principles of the ecological and epidemiological classification. An absolute "must know" for clinical clearance is knowledge of the list and characteristics of quarantine infections. Without understanding these basics, clinical thinking is impossible.
Why are pyogenic infections so dangerous in diabetes mellitus?
Diabetes causes complex immunodeficiency: general metabolism is impaired, the immunostimulating effect of insulin is lost, and phagocytosis is directly suppressed. This deprives the body of adequate protection against pyogenic bacteria.
Why is innate species immunity called relative?
Because it can be compromised by environmental influences. For example, chickens that are naturally resistant to anthrax contract the disease under severe hypothermia.
How do infectious diseases differ from infestation diseases?
Infectious diseases are caused by pathogenic bacteria, viruses, or fungi. Infestation (or parasitic) diseases are triggered by protozoa, helminths, and insects.
How does a relapse differ from an exacerbation?
Exacerbation occurs when symptoms were already subsiding, but complete clinical recovery has not yet occurred. A relapse is the return of symptoms after they have completely disappeared.
Why is the term "virulence" not applied to viruses?
Non-pathogenic forms do not exist among viruses in principle, as they are obligate parasites at the genetic level. Therefore, the terms "infectivity" or "infectiousness" are used to evaluate their properties.
What is an abortive infection and why does it occur?
This is a type of infection in which the virus replication cycle is interrupted and new infectious particles are not formed. The causes may include the absence of necessary factors within the cell itself (non-permissiveness), infection with a defective virus lacking a full set of genes, or exposure to defective interfering particles.
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