VIRUSES Flashcards
Name 5 Flaviviruses
HCV (only one not an arbovirus), Yellow fever, West Nile, St. Louis encephalitis, and Dengue
What determines tropism when phenotypic mixing of viruses occurs?
The coat that the virus takes with it (this is when 2 viruses infect a cell and one takes the other’s coat; HOWEVER, after infection in the new tissue, the virions expressed will have their original coat)
What are 4 important paramyxoviruses?
Parainfluenzae (croup), Respiratory Syncytial Virus (RSV), Measles (rubeola) and Mumps (all can form syncytia)
Which picornavirus is not spread via a fecal oral route?
Rhinovirus
Which RNA viruses are NOT ssRNA?
Reoviridae (rotavirus)
What is Gerstmann-Straussler-Scheinker syndrome?
inherited prion disease
Which cause of hepatitis is a picornavirus?
HAV
What are the likely organisms for the following neurologic findings in an AIDS pt 1) Encephalopathy 2) Abscess 3) Meningitis 4) Retinitis 5) Dementia
1) JC virus reactivation 2) Toxoplasma gondii 3) Cryptococcus neoformans 4) CMV (with cotton wool spots) 5) directly related to HIV
What is the structure of the Parvovirus genome?
ssDNA and linear (smallest DNA virus; largest = poxviruses)
What is a Tzanck test used to detect? What is it looking for?
Herpes (HSV 1 and 2, and VZV); it is looking for multinucleated giant cells
What is an adult infection with parvovirus like?
Rheumatoid arthritis-like with pure red cell aplasia
What are HHV 3, 4, and 5?
3 = VZV, 4 = EBV and 5 = CMV
What monoclonal antibody is used to prevent pneumonia from RSV infection in premature infants? MOA
Pavalizumab (binds to F protein, fusion protein)
Which RNA viruses do not replicate in the cytoplasm?
Influenza and retroviruses
Most common cause of sporadic encephalitis in US
HSV-1
Which hepatitis is a flavivirus? Which is a picornavirus?
Flavivirus enveloped (+) ssRNA = Hep C; Picornavirus naked (+) ssRNA = Hep A
What type of genome must a virus have in order to do recombination?
Segmented
Can you give live-attenuated vaccines to HIV patients?
If they are not showing signs of IC then it is at least safe (according to FA) to give them the MMR
What are 3 cancers associated with EBV?
1) Hodgkin’s lymphoma 2) Burkitt’s lymphoma and 3) Nasopharyngeal carcinoma (Asians)
Name 2 recombinant vaccines
HBV and HPV (6 and 11 = warts; 16 and 18 = cervical CA)
What kind of virus is Lymphocytic Choriomeningitis virus?
LCMV = Arenavirus
Which virus can cause a heterophile antibody negative (sheep abs) infectious mononucleosis?
CMV
What is the kissing disease? What is transmitted by the kissing bug?
Epstein-Barr virus; Trypanosoma cruzi
What are atypical lymphocytes? Are they infected?
Reactive cytotoxic T cells that are responding to EBV infection of B cells
What causes pure red aplasia and rheumatoid arthritis like Sx in adults?
Parvovirus B19
How do you get HSV-1?
Respiratory secretions and saliva
What inclusion body do you commonly see in herpes infections?
Cowdry type A intranuclear (intranuclear because herpes viruses replicate IN THE NUCLEUS!)
What kind of virus is norovirus? Rotavirus?
Norovirus = a calicivirus (SS linear RNA), Rotavirus = a reovirus (DS linear 10-12 segments RNA)
Name 3 togaviruses
Measles (Rubella), Eastern Equine encephalitis; Western Equine encephalitis
What is exanthem subitum?
Roseola (HHV-6)
What are the 5 picornaviruses?
Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, HAV
What cells are infected by EBV? Receptor?
B cells; CD21
What 3 enzymes are coded for on pol gene in HIV?
reverse transcriptase, aspartate protease, and integrase
What mutations lead to immunity of AIDS? Which for a slower course?
Homozygous CCR5 mutations; Heterozygous CCR5 mutations
What is viral reassortment?
Occurs when viruses with segmented genomes exchange segments of their genomes (co-infect a cell)
What is viral phenotypic mixing?
When 2 viruses infect a cell and one virus takes the coat of the other virus
What are the 6 live attenuated vaccines?
Nasal spray influenza, MMR, Yellow fever, Sabin polio, small pox, and chickenpox
Where do most enveloped viruses get their envelope? Where do herpes viruses get theirs?
Plasma membrane of the cell they are infecting; the nuclear membrane
Which flavivirus is NOT an arbovirus?
HCV
What is the test of choice for HSV?
PCR, however, you can identify it with a Tzanck smear of an opened skin vesicle
Which virus can lead to hydrops fetalis in utero and death?
Parvovirus B19
Anti-HAV IgM
active HAV
What are the early and late co-receptors on CD4 for HIV?
Early = CCR5 (MO and CD4); Late = CXCR4 (CD4)
Why is the live-attenuated vaccine for influenza given nasally?
It can replicate in the nose but cant make it to the lungs
What 2 diseases are caused by coronaviruses?
second most common cause of common cold as well as SARS
What are the 4 segmented viruses?
Bunyaviruses, Orthomyxoviruses, Arenaviruses, and Reoviruses
How is Lassa fever virus spread?
By mice (Arenavirus)
Which hepatitis vaccine is killed? Which is recombinant?
HAV; HBV
What kind of virus is norovirus?
Calicivirus (+) ssRNA causes viral gastroenteritis in adults
Which DNA virus is not icosahedral?
poxvirus (it is complex)
What are the 2 main retroviruses?
HTLV (T-cell leukemia) and HIV
Why does HBV increase risk of HCC? HCV?
HBV because it integrates into genome; HCV because it causes chronic inflammation
Which DNA genome viruses are circular?
Polyomaviridae, Papillomaviridae, Hepadnaviridae
What is the structure of the poxvirus genome?
dsDNA and linear (largest DNA virus)
Where does CMV go latent? EBV?
CMV in mononuclear cells; EBV in B cells
Where do most DNA viruses replicate? RNA viruses?
DNA viruses = nucleus; RNA = cytoplasm
Which virus carries its own DNA-dependent RNA polymerase?
Poxvirus
What kind of viruses are HCV, yellow fever, Dengue, St. Louis encephalitis, and West Nile virus?
Flaviviruses (+) ssRNA
What kind of virus is Rabies?
Rhabdovirus enveloped (-)ssRNA
Discuss the ontogeny of a roseola infection
Usually HHV-6, though can be HHV-7, leads to high fevers that may lead to febrile seizure and then abrupt defervescence followed by maculopapular rash
Which DNA genome viruses are NOT double stranded?
ONLY parvoviridae (all others are dsDNA)
What term describes when 2 viruses infect a cell and one makes a dysfunctional protein so the other virus decides to be a bro and make the functional version of the protein for its fellow virus?
Complementation
Which RNA viruses have 10-12 segments? 8 segments? 2 segments? 3 segments?
10-12 = Reoviridae; 8 = orthomyxoviridae 2= Arenavirus 3 = Bunyaviridae
What do all paramyxoviruses contain that allows them to make syncytia?
F protein (fusion protein, molecular target of Pavalizumab)
What is p17? P24? (in HIV)
p17 = matrix proteinl; p24 = capsid protein (from gag gene)
Which cells contain Negri bodies?
Purkinje cells of cerebellum (intracytoplasmic inclusion)
Where does HIV replicate during the latent phase?
lymph nodes
Which herpes virus is most likely to cause febrile seizures in a child?
HHV-6 since they have the high fever and abrupt defervescence followed by rash
What causes temporal lobe encephalitis?
HSV-1
Primary CNS lymphoma in an AIDS pt is actually caused by _______-
EBV usually
What is viral recombination?
The exchange of genes between 2 CHROMOSOMES by crossing over regions of significant base sequence homology
Name 4 paramyxoviruses
Measles, Mumps, Parainfluenza (croup) and RSV
What is the number 1 cause of fatal diarrhea in children?
Rotavirus
4 bunyaviruses
Crimean-Congo hemorrhagic fever, Hantavirus, Sandfly/Riftvalley fever, and California encephalitis
Worldwide vector for rabies?
Dog (bat, racoon, and skunk in U.S.)
Which DNA virus does NOT replicate in the nucleus?
Poxvirus
Which RNA viruses are dsRNA?
Reoviridae (rotavirus)
Function of hemagluttinin? Function of neuraminidase?
Hemagluttinin = viral entry; Neuraminidase = viral exit
What is the smallest DNA virus?
Parvovirus (ssDNA all others are ds)
What is the structure of the hepadnavirus genome structure?
dsDNA and partially circular
What proteins are coded for on the env gene of HIV? What is the direct precursor to these?
gp120 (attach to CD4), gp41 (fusion); come from gp160
What is the structure of Herpesviridae genome?
dsDNA and linear
Which virus is a rhabdovirus?
Rabies
What kinds of viruses cause ebola and Marburg?
Filoviruses (-) SS linear RNA
Which picornavirus is not an enterovirus? Why?
Rhinovirus because it is acid labile
What is the structure of the Adenovirus genome?
dsDNA and circular
Which lymph nodes are most affected by EBV mononucleosis?
posterior cervical
Which viruses obtain their envelope from the nuclear membrane?
Herpesviruses
What occurs when 2 viruses infect a cell and one virus is packaged in the other virus’ coat?
Phenotypic mixing
What family is the influenza virus in?
Orthomyxoviridae
Pavalizumab best inhibits the ability of paramyxovirdae to do what?
Form syncytia; it is against the F fusion protien
What are the largest DNA viruses?
Poxviruses
What is viral complementation?
When 2 viruses infect a cell and 1 virus makes a dysfunctional protein so the other virus donates a functional version of that protein to the dysfunctional virus
What is Hepevirus?
(+) ss linear RNA virus that cause Hep E (pregnant women, fecal oral)
What is the structure of the virus that causes aplastic crisis in sickle cell disease?
Parvovirus (ssDNA all others are ds)
Which DNA virus family is dsDNA and partially circular
Hepadnaviruses
What enzyme MUST a negative stranded RNA virus have with it? What are the 6 negative stranded viruses?
RNA dependent RNA polymerase? Arenavirus, Bunyavirus, Paramyxovirus, Orthomyxovirus, Filovirus, and Rhabovirus
Which hepatitis viruses are RNA?
All except HBV (hepadnavirus); So, HAV (picornavirus), HCV (flavivirus), HEV (hepevirus), and delta agent (RNA delta virus)
If you are infected with HHV-3 what are you infected with?
VZV
What does a negative stranded virus bring with it?
RNA dependent RNA polymerase
What is the most common and least common cause of roseola?
Most common = HHV-6; Least common = HHV-7
What occurs when there is exchange of genes between 2 chromosomes by crossing over areas with significant base sequence homology?
Recombination
Which virus can cause an acute hemorrhagic cystitis?
Adenovirus (dsDNA, linear)
Why are screening tests for AIDS often falsely positive in newborns of infected mothers?
because gp120 can cross the placenta
Which DNA viruses are NOT linear?
papilloma and polyoma (circular and supercoiled), hepadna (circular and incomplete)
Name 2 poxviruses
Molluscum contagiosum; Smallpox (cowpox = vaccinia)
What viral family (aside from HIV, which isnt really a family anyway) transcribes its RNA into 1 protein and then cleaves it?
Picornaviridae (polio, echo, rhino, coxsackie, HAV)
What is the most common cause of sporadic encephalitis in the US?
HSV-1
What is delta virus?
Hep D (requires Hep B to infect)
What protein comes from the gag gene of HIV?
p24 (capsid protein, used to detect viral load)
For which Herpes virus does a vaccine exist?
VZV
What is the genetic makeup of the polyomaviruses? Name 2 and their associated Dz
DS circular DNA; JC = progressive multifocal leukencephalopathy in AIDS; BK = targets kidney transplants
What is the difference in the rash of measles and rubella?
Rubella is a truncal rash typically starting on head and moving down; Measles is a full body rash)
What antibody is positive during the window period of HBV infection?
Anti-HBc (core antibodies) IgM
What are 5 important Flaviviruses?
HCV, Yellow fever, Dengue fever, St. louis encephalitis, West Nile virus
What are 4 killed vaccines?
Rabies, Injectable influenza, Salk Polio, and HAV
What detects active HAV infection?
Anti-HAV IgM
What herpes virus has the classic owl’s eye inclusion?
CMV
Which DNA virus replicates in the cytoplasm?
Poxvirus (i.e. smallpox, molluscum)
What antigen is used in the recombinant HBV vaccine?
recombinant surface antigen HBsAg
What are heterophile antibodies?
Antibodies that are used in the monospot test for EBV that agglutinate horse or sheep RBC’s
Name 2 viral causes of aseptic meningitis
echovirus, coxsackievirus (both picornaviridae)
4 areas that can get hit by mumps
Pancreas, Parotids, Testes (orchitis), and Meninges (aseptic meningitis).. .Note, mumps is a paramyxovirus
What are 2 important members of Reoviridae?
Coltivirus (Colorado tick fever) and Rotavirus (#1 cause of fatal diarrhea in kids)
What is the structure of the papillomavirus genome?
dsDNA and circular
What virus is not a retrovirus but contains reverse transcriptase?
HBV
What kind of viruses are Rubella, Eastern Equine encephalitis, and Western equine encephalitis?
Togaviruses (+) ssRNA
Which DNA genome viruses are NOT linear?
Papillomaviridae, Polyomaviridae, and Hepadnaviruses (CIRCULAR)
Which viruses are diploid?
Retroviruses contain 2 copies of ssRNA
