Viral Infection Of Skin And Joints Flashcards
(20 cards)
What are the main physiological functions of the skin as outlined in the lecture?
Protection against microbial agents, water and heat loss, trauma, pigment production (melanocytes), keratin production (keratinocytes), and antigen processing (Langerhans’ cells).
Describe the function of keratinocytes in the epidermis.
Keratinocytes produce keratin, forming the outermost skin layer. This layer is covered by thin lipids that provide a protective barrier.
What is the role of Langerhans’ cells in the skin?
Langerhans’ cells are dendritic cells specialized in antigen processing and presentation, contributing to immune response initiation.
What are maculopapular rashes, and which viruses are associated with them?
Flat to slightly raised colored bumps associated with Measles (Rubeola) and Rubella (German Measles).
Explain the significance of Koplik’s spots in measles infection.
Koplik’s spots are small, white lesions with a red halo that appear on the oral mucosa during measles infection, aiding in clinical diagnosis.
What is the genomic structure of the Measles virus (MeV)?
MeV is a negative-sense RNA virus with a 16kb genome and a lipid envelope, belonging to the morbillivirus genus of the Paramyxoviridae family.
What is Congenital Rubella Syndrome (CRS), and what are its clinical manifestations?
CRS occurs when the Rubella virus infects a fetus, causing developmental defects like blindness, hearing loss, and heart problems.
How does the Varicella Zoster Virus (VZV) establish latency in the human body?
VZV travels to sensory ganglia via neuronal axons or viremia, establishing latency in neuronal nuclei, which can later reactivate as shingles.
What is the typical clinical presentation of Molluscum Contagiosum, and what virus causes it?
Discrete, flesh-colored papules with a central umbilication caused by a DNA virus from the Poxviridae family.
Why was the eradication of smallpox possible, and what role did vaccination play in this effort?
Absence of an animal reservoir, effective vaccination using vaccinia virus, and ring vaccination strategies were key.
What are the primary components of the skin’s natural defenses against viral infections?
Keratin, skin sloughing, sebum (low pH, high lipid), sweat (low pH, high salt), lysozyme (digests peptidoglycan), and RNase (digests RNA).
Which skin cells are responsible for antigen presentation and immune response initiation?
Langerhans’ cells, which are dendritic cells specialized in antigen processing and presentation.
What are the key clinical features of a measles infection and its characteristic rash?
Maculopapular rash that begins on the face and spreads to the trunk and extremities, with Koplik’s spots in the oral mucosa.
Describe the viral structure of the Measles virus (MeV).
MeV has six proteins: hemagglutinin (H), fusion (F), matrix (M), nucleocapsid (N), phosphoprotein (P), and large (L) polymerase protein.
How does Rubella infection differ from measles in terms of clinical severity and complications?
Rubella is milder and self-limiting but poses severe risks to fetuses, leading to Congenital Rubella Syndrome (CRS).
What is the primary mechanism by which VZV establishes latency in the host?
VZV establishes latency in sensory ganglia after initial infection through neuronal axons or viremia.
What are the clinical manifestations of herpes simplex virus (HSV) infection in immunocompromised patients?
Severe disseminated lesions, encephalitis, and systemic infection; HSV-1 typically presents as cold sores, HSV-2 as genital lesions.
Explain the life cycle of the varicella zoster virus (VZV).
VZV infects mucosal epithelial cells, spreads to lymphoid tissues via T cells, and establishes latency in sensory ganglia.
What is the significance of a ‘shotty’ rash in smallpox, and how does it differ from chickenpox?
Smallpox rash consists of firm, deep-seated pustules (‘shotty’), unlike the superficial vesicles of chickenpox.
What is the most effective prevention strategy for smallpox and how was it utilized during eradication efforts?
Vaccination using live vaccinia virus, ring vaccination, and strict isolation of infected patients.
