7 topics with concise reviews: definitions, key facts, and class questions.
Acute respiratory viral infections (ARVI) are the most frequent reason for seeking medical care. In this section, we examine the properties of the main respiratory viruses, as well as slow infections—prion diseases—which have historically been included in this module.
The material covers the entire chain of the infectious process: from epidemiology and mechanisms of development (pathogenesis) to clinical manifestations. Special attention is paid to the development of antiviral immunity and modern methods of microbiological diagnostics that every clinician must know.
In seminars and exams, instructors are strictest about testing laboratory diagnostic algorithms (choice of specimen, PCR, ELISA, virological method) and the mechanisms of the immune response. Prions are usually asked as a tricky bonus question for a high grade—be ready to clearly explain their protein nature, resistance to sterilization, and mechanism of CNS damage.
Prions are a modified form of the body's own proteins; therefore, they are not recognized by the immune system as foreign agents, and neither inflammatory infiltrates nor classical antibodies are formed.
Prions do not induce a classical immune response in the body.
Can the measles virus or mumps virus be considered ARVI pathogens?
No. Although these viruses are transmitted via airborne droplets and also affect the respiratory tract, true ARVI pathogens are considered to be only those whose primary replication occurs exclusively in the respiratory epithelium.
Why do ARVI outbreaks occur more frequently in winter?
The peak incidence during the cold season is due to the fact that virus infectivity is preserved much better at low ambient temperatures.
Why do severe mucosal edema and runny nose occur in ARVI?
Local manifestations of the infection (edema, rhinorrhea) are caused not only by the replication of the virus itself, but also by the active release of tissue inflammatory mediators, primarily bradykinins.
Why do serum antibodies fail to protect during the acute phase of ARVI?
They are produced too slowly and fail to reach protective concentrations in the blood before the acute phase of the disease runs its course and resolves.
Why is the serological method used primarily for retrospective diagnostics?
The duration of clinical manifestations of the disease is usually 5–7 days, which is significantly shorter than the time required for full antibody production. Reliable analysis requires paired sera with an interval of 10–14 days, by which time the patient has already recovered.
Study the full topic in the «Microbiology» course
This is a summary. The course covers everything tested in classes and exams.
4,383 pages of study guides across all topics
Assignments and quizzes after every topic — just like in a colloquium