Viruses Flashcards
enveloped, dsDNA, linear poxvirus that causes single or multiple lesions that are smooth, 2-6 mm wide, witish or skin-colored, firm and apear and “pearly papules” with central umbilication
molluscum contagiosum
What is HHV-6,7
Roseola infantum
all herpes viruses are _____ (viral characteristics)
eveloped, double stranded DNA, linear
Segmented viruses R BOARing
segmented viruses are all RNA viruses and are capable of reassortment with co-infection
BOARing
Bunyavisuses - hantavirus (hemorrhagic fever + pneumo)
Othomyxoviruses - influenza
Arenaviruses - lymphocytic choriomeniengitis virus LCMV
Reoviruses - rotavus
Teacher with stillbirth had symptoms of 1 week symmetric arthralgia during pregnancy. She may or may not have had a rash. Autopsy of fetus showed pleural effusions with secondary pulmonary hypoplasia and effusions and ascites. What was the cause of still birth?
Congential Parvovirus B19 infection leading to hydrops fatalis
non-enveloped, single stranded DNA virus
how does parvovirus B19 cause fetal hydrops fatalis?
interrups erythropeoisis resulting in profound anemia and congestive heart failure which can cause pleural effusions, pericardial effusions and ascites.
also causes aplstic crisis in sickel cell disease and 5th disease - slapped cheek rash in children
VZV, CMV and HSV share what viral characteristics?
enveloped, doubled stranded DNA virsuses
Pregnant woman in second trimester is exposed to a virus that causes fetal limb hypoplasia, microcephaly and chorioretinitis. What was the virus?
VZV - fetal vericella syndrome
A newbown is found to have sensineural deafness, jaundice, hepatosplenomegaly, chroioretinitis and periventricular calcifications. Congenital infection with what virus causes these symptoms?
CMV
A prenant woman has a stillbirth due to viral infection that caused intrauterine death. Autopsy shows microcephaly and scaring vasicular lesions. What was the causal agent?
HSV
Infant is born with cateracts, sensorineural deafness, congential heart disease (PDA + pulmonary artery stenosis), and purperitic lesions that resemble a blueberry muffin rash. What was the infectious agent?
congential rubella infection
purpuritic rash signifies dermal erythropeoisis
newborn presents with chorioretinitis, hydrocephalus, intracranial calcifications, microcephaly and seizures. what is the causal agent?
toxoplama gondii - obligate intracellular protozoan
Congenital Rubella and CMV have sensorineural deaffness and hepatospelnomegally - what differentiates them?
Rubella has purpuritic rash (blueberry muffin) and congenital heart disease - CMV doesn’t present with rash
CMV also has periventricular calcifications - rubella has no brain calcifications.
T/F congenital CMV, Toxoplasmosis and VZV all have chorioretinitis
True
if chorioretinitis without Intracranial calcifications ==> VZV
If chorioretinitis with intracranial calcifications =>Toxo or CMV
chorioretinitis with intracranial calcifications +hydrocephalus = toxo
chorioretinitis with intracranial calcifications
+sensineural deafness = CMV
what type of virus is hepititis B?
circular dsDNA virus with neucleocapsid core (containing Hep B core antigen) covered by outer liprotein evelope (containing hep B surface antigen)
describe the replication sequence of Hep B
following viral entry and import to the nucleus the Heb B
dsDNA=> +RNA template => dsDNA progeny
circular dsDNA serves as a template for transcirption into an intermediate AND a single stranded RNA. The RNA strand serves as a template for BOTH translation of viral proteins (including a polimerase and reverse transcriptase), AND reverse transcription into a singled stranded DNA intermediate that is then converted back into a dsDNA
what kind of virus is for parvovirus B19? is it enveloped? What disease does it cause? What is the classic presentation? What is the replication sequence?
paravirus is a singles stranded, non-enveloped DNA virus that causes erythema inefctiosum or 5th disease
classic presentation is with fever, ough, rhinorrhea, followed by slapped cheek and lacy, reticular truncal rash
ssDNA => dsDNA template => ssDNA progeny
what type of virsuses are adenovirus, herpesvirus and poxvirus? are they enveloped? what are the replication sequences?
double stranded DNA viruses
adenovirus is not enveloped – herpes, and poxvirses (e.g. small pox) are enveloped
dsDNA => dsDNA template => dsDNA progeny
what is the replication sequence for poliovirus?
+ssRNA => -ssRNA template => +ssRNA progeny
what is the replication sequence for retroviruses (e.g. HIV)?
+ssRNA => dsDNA template => +ssRNA progeny
what is the replication sequence for influenza virus, measles virus and rabies virus?
-ssRNA => +ssRNA template => -ssRNA progeny
What is the function of viral RNase H?
required retrovirus enzyme that removes the RNA primer allowing for completion of newly synthesized DNA
what is the mechanism of a drug that would be used to treat HSV encephalitis?
inhibition of viral DNA polimerase
what type of virus is rotavirus?
reovirus
double-stranded, positive sense, non-enveloped DNA virus
causes profuse watery diarrhea in children - vaccine exists
which are directly translated into proteins, negative or positive sense RNA virses?
positive sense
what type of virsuses are coxackie virses?
single stranded, positive sense RNA viruses of the enterovirus family that causes hand foot and mouth disease - presents with vasciular lesions on the buccal mucosa, tounge and soft palate
DIFFERNTIATE FROM HSV by involvement of the gums and hard palate (coxackie doesn’t affect these areas)
what are two viral causes of aplastic anemia?
paravirus B19 and EBV
