Chap8- Viral Infections Flashcards
What viruses attack upper respiratory tract
adenovirus
rhinovirus
influenza viruses A B
Respiratory syncytial virus
What viruses affect the digestive tract
mumps rotavirus- childhood norovirus Hep A Hep B Hep D Hep C Hep E
What viruses cause systemic with skin eruptions
measles rubella varicella zoster Herpes simplex virus 1 Herpes simplex virus 2
What viruses cause systemic with hematopoietic disorders
CMV
EBV
HIV 1 and 2
What are the arboviral and hemorhhagic fever viruses
dengue virus1-4
yellow fever
what virus causes skin warts
papillomavirus
What viruses affect CNS
polio and JC
How do you confirm a measles Dx
detection of viral antigen in nasal exudate or urinary sediment
What type of virus is measles
ss RNA of the paramyxovirus family
What virus causes croup
parainfluenza virus
What cell R are associated with measles
CD46- C’ regulatroy protein that inactivates C3 converses
SLAM- involved in T cell activation
How does measles spread
respiratory droplets and from there can multuply in epithelial cells, endothelial, monocytes, macrophages, dendritic cells and lymphocytes
What does measles cause clinically
croup, pneumonia, diarrhea with protein-losing enteropathy, keratitis with scarring and blindness, encephalitis and hemorrhagic rashes in malnourished children
Most people develope what type immunity to measles
T cell, with hypersensitivity rash
What is the cause of measles morbiditiy and mortality rates
its immunosuppression resulting in secondary bacterial and viral infection
What are some of the late complications of measeles
subacute sclerosing panencephalitis and inclusion body encephalitis
What does the rash to measles look like and what causes it
blotchy reddish, brown rash on face, trunk and proximal extremities
from dilated skin vessels, edema and mononuclear perivascular infiltrate
What are the pathonomonic findings in measles
Koplik spots, ulcerated mucosal lesions in oral cavity near opening
Warthin-Finkeldey cells- multinucleate giant cells in lymphoid tissue
What are the 2 types of glycoproteins on the mumps virus
one with hemagglutinin and one with neuraminidase activities
Where does mump replicate
preferentially in activate T cells
travel in drained lymph
What are common signs of mumps
salivary gland pain and aseptic meningitis
Describe morphology of the parotitis in mumps
moist, glistening and reddish brown
diffusely infiltrated by macrophages, lymph and plasma cells which compress acini and ducts
some neutrophils and necrotic debris
Describe morphology mumps orchitis
swelling from edema and mononuclear cell infiltration with focal hemorrhages
can have ares of infarction leading to sterility
What does mumps look like in pancreas
fat necrosis and neutrophil rich inflammation
describe mumps encephalitis
causes perivenous demylination and perivascular mononuclear cuffing
What type of virus is polio
unencapsulated RNA from the enterovirus genus
What are the enteroviruses
coxsackievirus A and B, enterovirus 70, echovirus
How many strains are there of polio and what vaccines are available
3 strains
the salk formalin(killed) and sabin oral (attenuated live) have all 3
how is polio transmitted
oral fecal route
multipling in intestinal mucosa and lymph nodes
Why does polio only affect humans
uses human CD155 to gain entry
What group of viruses does west nile belong to
arbovirus of flavivirus group
Where does west nile replicate
in dendritic cells then migrating to lymph nodes where it can enter blood stream and potentially cross bbb
What is the double edge about CCR5
without it more prone to west nile
with it- can be affect by HIV
What are the symptoms of west nile if any
short lived febrile illness with HA and myalgia
maculopapular rash in some
What is found in brains of those who died of West nile
perivascular and leptomeningeal chronic inflammation with microglial nodes and neronophagia in temporal lobes and brain stem
what is the best way to confirm Dx of west nile
usually serology but viral culture and PCR used too
what type of viruses cause viral hemorrhagic fevers and what are the 4 families
enveloped RNA viruses
arenaviruses, filoviruses, bunyaviruses and falviviruses
what are the mild acute diseases cause by viral hemorrhagic fevers VHF
fever, HA, myalgia, rash, neutropenia and thrombocytopenia
what are the severe diseases cause by VHF
hemodynamic deterioration and schock
What immune response contributes to VHF
innate because activation of macrophages leads to release of mediators that modify vascular function
What type of DNA is herpes
ds DNA
what are the categories of herpes and types of cells they each infect
alpha group: HSV 1 and 2, VZV infecting epithelial cells and latency in neurons
lymphotropic beta group: CMV, herpes-6 and herpes-7 infect a variety of cells
-group: EBV KSHV-8 latent infections in lymphoid cells
Where do HIV 1 and 2 replicate
in the skin and mucous membranes at site of entrance where they cause vesicular lesions
What occurs during latency in HSV
viral DNA remains in nucleus and viral RNA trancripts are synthesized
no viral proteins are produced
how do HSV evade CTLs
inhibit class I MHC and elude humoral immune defenses by producing R for the Fc domain of Ig and inhibitors of C’
Where in the brain does HSV attack first
temporal lobes, orbital gyri of frontal lobes
what do HSV cells looks like
large with inclusions that have intact disrupted virions with stained host cell chromatin pushed to edges of nucleus
what is gingivostomatitis
children with HSV-1 that have a vesicular eruption extending from tongue to retropharynx casing cervical lymphadenopathy
What does HSV-2 look like in neonate
mild, more commonly with generalized lymphadenopathy, splenomegaly and necrotic foci throughout lungs, liver, adrenals and CNS
What type of corneal lesions does Herpes cause
herpes epithelial keratitis- cytolysis of superficial epithelium
herpes stromal keratitis- infiltrates of mononuclear cells around keratinocytes and endothelial cells–>neovascularization, scarring, opacificaiton of cornea and eventual blindness
What is kaposi varicelliform eruption
generalized vesiculating involvement of skin
what is eczema herpeticum
confluent pustular or hermorrhagic blisters with bacterial superinfection and viral dissemination to internal viscera
how does herpes affect resp tract
herpes esophagitis and bronchopneumonia
what conditions are caused by varicella zoster virus
chicken pox and shingles
how is VZV transferred
aerosols, and causes widespread vesicular skin lesions
Describe the recurrence of VZV
painful in dermatomes innervated by trigem ganglia
How is VZV Dx confirmed
viral culture or detection of viral Ag in cells from superficial lesions
what do chicken pox vesicles have in them
intranuclear inclusions in epithelial cells like that of HSV-1
What is shingles
when VZV has been latent a long time, after having chicken pox
will infect keratinocytes that have vesicular lesions assoc with itching, burning or sharp pain
What can VZV cause in immunocompromised patients
interstitial pneumonia, encephalitis, transverse myelitis, necrotizing visceral lesions
What type of cells does CMV attack latently
monocytes and their bone marrow progenitors
What does CMV cause in healthy patients? neonateS? immunocompromised?
asymptomatic or mononucleosis like infection with fever and lymphadenopathy, hepatomegaly
intrauterine: cytomegalic inclusion disease- growth retardation, jaundice, HSM, anemia, encephalitis, microcephaly, deafness
perinatal: interstitial pneumonitis, skin rash, hepatitis, failure to thrive
immunocompromised pneumonitis, colitis, ARDS, intestinal necrosis with formation of pseudomembranes and diarrhea
What cells does CMV acutely affect
dendritic cells and impair their maturation and ability to stimulate T cells
how does CMV elude immune system
downmodulates Class I and II MHC and produces homologues to TNF R, IL 10 and MHC I
how does CMV affect NK cells
activate and evade NK cells by inducing ligands for activating R
What do CMV cells look like morpho
enlarged
intranuclear basophillic inclusions spanning half the nuclear diameter
what tissues and components are affected by CMV
glands- parenchymal epithelium
brain- neurons
lungs- alveolar macrophages
kidneys- tubular epithelium and glomerular endothelial
What is the most common opportunistic viral pathogen in AIDS
cytomegalovirus
What does HBV (HepB) cause
acute and chronic liver disease
how is HBV transmitted
drug IV, blood, perinatally, sexually
The cellular injury of liver from HBV occurs how
from immune response to infected liver cells
when the rate of infection overcomes rate that CTL can clear virus
Patients with HBV are at increased for developing what
hepatocellular carcinoma
What does EBV cause
infectious mononucleosis, self limited lymphoproliferative disorder
assoc with developing neoplasms like lymphomas and nasopharyngeal carcinoma
What are the symptoms of EBV
fever, generalized lymphadenopaty, splenomegaly, sore throat and blood of atypical T lymphocytes
How is EBV transmitted
saliva, kissing
What type of proteins are on EBV
CD21 (CR2) whicis the R for C’3d on B cells
what are the ways that B cells are infected
lysis of infected cells releasing virions that can infect other cells
majority just establish latent infection
What type of disease is protective for EBV
X- agamaglobulinemia because don’t have B cells
What are the gene products of EBV latency
EBNA1 which mediates maintenance
EBNA2 and latent membrane protein1 LMP1 that dirve proliferation
What type of R does the LMP1 from EBV bind
TNFR activating pathways that mimic B cell activation by CD40
What is used Dx for EBV
detection of heterophile anti-sheep red blood cell Ab
What cells are most important against EBV
CD8 CTLs and NK cells
What type of lymphomas does EBV contribute to in immunocompromised patients
B cell lymphomas
Burkitt lymphoma with the 8:14 translocation amplifying c-myc
what is characteristic of EBV in peripheral smear
lymphocytosis with >60% WBC and many of them being atypical huge with many clear vacillations and oval indented nucleus with scattered granules
where are lymph nodes enlarged first in EBV
groin, axillary and posterior cervical
What areas of lymph nodes are expanded in EBV
paracortical by activated T cells
The Dx of EBV depends on what
lymphocytosis with characteristic atypical lymphocytes in peripheral blood
+ heterophile Ab rxn
specific Ab for EBV Ag
what disease if concurrent with EBV infection is fatal in 1/3 patients
X linked lymphoproliferation syndrome “Duncan disease”
