Viruses

Question 1

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

Answer 1

molluscum contagiosum

Question 2

What is HHV-6,7

Answer 2

Roseola infantum

Question 3

all herpes viruses are _____ (viral characteristics)

Answer 3

eveloped, double stranded DNA, linear

Question 4

Segmented viruses R BOARing

Answer 4

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

Question 5

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?

Answer 5

Congential Parvovirus B19 infection leading to hydrops fatalis

non-enveloped, single stranded DNA virus

Question 6

how does parvovirus B19 cause fetal hydrops fatalis?

Answer 6

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

Question 7

VZV, CMV and HSV share what viral characteristics?

Answer 7

enveloped, doubled stranded DNA virsuses

Question 8

Pregnant woman in second trimester is exposed to a virus that causes fetal limb hypoplasia, microcephaly and chorioretinitis. What was the virus?

Answer 8

VZV - fetal vericella syndrome

Question 9

A newbown is found to have sensineural deafness, jaundice, hepatosplenomegaly, chroioretinitis and periventricular calcifications. Congenital infection with what virus causes these symptoms?

Answer 9

CMV

Question 10

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?

Answer 10

HSV

Question 11

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?

Answer 11

congential rubella infection

purpuritic rash signifies dermal erythropeoisis

Question 12

newborn presents with chorioretinitis, hydrocephalus, intracranial calcifications, microcephaly and seizures. what is the causal agent?

Answer 12

toxoplama gondii - obligate intracellular protozoan

Question 13

Congenital Rubella and CMV have sensorineural deaffness and hepatospelnomegally - what differentiates them?

Answer 13

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.

Question 14

T/F congenital CMV, Toxoplasmosis and VZV all have chorioretinitis

Answer 14

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

Question 15

what type of virus is hepititis B?

Answer 15

circular dsDNA virus with neucleocapsid core (containing Hep B core antigen) covered by outer liprotein evelope (containing hep B surface antigen)

Question 16

describe the replication sequence of Hep B

Answer 16

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

Question 17

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?

Answer 17

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

Question 18

what type of virsuses are adenovirus, herpesvirus and poxvirus? are they enveloped? what are the replication sequences?

Answer 18

double stranded DNA viruses

adenovirus is not enveloped – herpes, and poxvirses (e.g. small pox) are enveloped

dsDNA => dsDNA template => dsDNA progeny

Question 19

what is the replication sequence for poliovirus?

Answer 19

+ssRNA => -ssRNA template => +ssRNA progeny

Question 20

what is the replication sequence for retroviruses (e.g. HIV)?

Answer 20

+ssRNA => dsDNA template => +ssRNA progeny

Question 21

what is the replication sequence for influenza virus, measles virus and rabies virus?

Answer 21

-ssRNA => +ssRNA template => -ssRNA progeny

Question 22

What is the function of viral RNase H?

Answer 22

required retrovirus enzyme that removes the RNA primer allowing for completion of newly synthesized DNA

Question 23

what is the mechanism of a drug that would be used to treat HSV encephalitis?

Answer 23

inhibition of viral DNA polimerase

Question 24

what type of virus is rotavirus?

Answer 24

reovirus

double-stranded, positive sense, non-enveloped DNA virus

causes profuse watery diarrhea in children - vaccine exists

Question 25

which are directly translated into proteins, negative or positive sense RNA virses?

Answer 25

positive sense

Question 26

what type of virsuses are coxackie virses?

Answer 26

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)

Question 27

what are two viral causes of aplastic anemia?

Answer 27

paravirus B19 and EBV