Pathology Of Infectious diseases Flashcards
What is the definition of infectious diseases?
Infectious diseases are diseases in which tissue damage or dysfunction is produced by microorganisms.
Name the major groups of infectious agents.
Prions, Viruses, Bacteria, Mycoplasma, Rickettsiae, Chlamydia, Fungi, Parasites.
What is the relationship between virulence and host immune response in determining the outcome of infection?
The outcome depends on the virulence of the microorganism and the nature of the host immune response.
Define symbiosis in the context of host-organism interaction.
Symbiosis is a cooperative association between two dissimilar organisms, beneficial to both.
What is the difference between commensalism and parasitism?
Commensalism benefits one organism without harming the other, while parasitism benefits one organism at the expense of the other.
Name the major protective barriers against infection in the skin.
Epidermal barrier.
How do microbes gain entry into the human body via the gastrointestinal tract?
By overcoming acidic secretions, bile, pancreatic enzymes, and protective flora.
How do microorganisms evade host adaptive immunity?
By modulating their surface structure (antigenic variability).
What are some ways that microbes inhibit phagocytosis?
Through resistance to microbial peptides and inhibition of phagosome-lysosome fusion.
Describe the role of cytokines in host defense evasion by microorganisms.
Microorganisms resist cytokine-mediated defense mechanisms.
What is the main cellular event that leads to vascular damage in viral hemorrhagic fevers?
Direct infection and damage to endothelial cells or dendritic cells.
Which cells are responsible for removing apoptotic hepatocytes during yellow fever?
Kupffer cells.
What is the pathogenesis of yellow fever at the cellular level?
It involves midzonal necrosis of hepatocytes, apoptosis, and the formation of Councilman bodies.
How do viruses cause cellular death in host cells?
By preventing the synthesis of critical macromolecules or by activating apoptotic machinery.
What types of immune responses contribute to tissue damage in viral infections?
Antiviral immune responses such as cytotoxic T cell-mediated tissue damage.
Which body fluids are potential sources of transmission for Lassa fever?
Urine, saliva, semen, and other secretions.
What are the primary signs of Lassa fever in its initial stage?
General weakness and high fever.
How does Lassa fever cause hepatocellular necrosis?
Through high viral content and inflammatory damage.
What viral family does the Ebola virus belong to?
Filoviridae.
How is Ebola transmitted from animals to humans?
Through direct contact with infected animals or their fluids.
How does the Ebola virus affect immune cells?
It targets macrophages and dendritic cells, impairing immune responses.
What are the clinical features of dengue hemorrhagic fever?
High fever, myalgia, bleeding, hemoconcentration, and thrombocytopenia.
What is the role of monocytes in dengue virus infection?
Monocytes are infected by the virus, contributing to the immune response and disease progression.
How does hemorrhage occur in dengue hemorrhagic fever?
Due to thrombocytopenia, coagulopathy, and increased vascular permeability.