Viruses Flashcards
Picornaviruses: what are they and what are the 4 common ones?
- naked positive sense RNA viruses that are transmitted fecal-orally (except Rhinovirus, which is transmitted via respiratory droplets
- can be directly translated into DNA material; one long polyprotein that is cleaved into smaller pieces
- includes: Hepatitis A, enteroviruses (polio, coxsackie), and rhinovirus
Poliovirus: what is it and what does it affect, what are 3 clinical manifestations of it, and how does aseptic meningitis present?
- naked acid-stable RNA virus that replicates in Peyers Patches of the gut (lymphoid tissue) and affects motor neurons of the anterior horn of the spinal cord
- causes asymmetric paralysis, respiratory insufficiency, and ASEPTIC MENINGITIS
- aseptic meningitis presents with normal CSF glucose lvls, elevated CSF protein lvls, and most commonly affects children
Coxsackievirus A and B: what are they and how does each virus present clinically? What disease does each virus cause?
- naked positive sense RNA viruses
A: causes “hand, foot, and mouth” disease (red vesicular rash in mouth, palms, and soles), aseptic meningitis; commonly affects young children in the summer
B: causes myopericarditis (dilated cardiomyopathy), “Bornholm” disease or “Devils Grip” (severe unilateral pain in lower chest)
Rhinovirus: what is it and how is it transmitted, what does it bind to in the body, and what is its clinical manifestation?
- naked acid-labile positive sense RNA virus transmitted by respiratory droplets; washing hands reduces infection from foamites (WASH YO FUGGIN HANDS)
- binds ICAM-I of host cells (entry), grows well at 33 C and causes upper respiratory tract infections
- there are over 100 different serotypes, so it is hard to completely treat it
Hepatitis A: what is it and how is it transmitted (2), what are 7 common clinical findings of infection, and what does the virus cause in smokers?
- naked acid-stable positive sense RNA virus usually transmitted by contaminated water (can be boiled, chlorinated, irradiated, etc) in developing countries and contaminated shellfish in developed countries; symptoms typically last for 1 month (no carrier or chronic state)
- causes nausea, vomiting, abdominal pain, jaundice (mainly seen in adults), with smokers who develop it becoming adverse to smoking
- causes hepatitis, gastroenteritis, hepatosplenomegaly
Noravirus/Norwalk Virus: what is it and how is it transmitted, and what is its main clinical presentation?
- naked positive sense RNA virus that is translated into one long polyprotein and cleaved into smaller bits; outbreaks occur frequently in schools and cruises and is associated with consuming contaminated shellfish
- causes explosive watery diarrhea (#1 cause of diarrhea)
Flavivirus: what are they and what are the 4 known viruses of this family?
- enveloped positive sense RNA virus whose genome contains a SINGLE RNA segment
- include Hepatitis C, Dengue Fever, Yellow Fever, and West Nile Virus
Dengue Fever: what is it, how is it transmitted, and what are its two major clinical presentations?
- positive sense RNA virus transmitted by Aedes mosquito
- type 2 fever = “Break Bone Fever”
- classic presentation can progress to dengue hemorrhagic fever (thrombocytopenia/renal failure)
Yellow Fever: what is it, how is it transmitted, and what are 3 clinical findings of infection?
- positive sense RNA virus transmitted by Aedes mosquito
- present with jaundice, severe backache, and is a hemorrhagic fever (bloody stool and vomit)
West Nile Virus: what is it, how is it transmitted, and what are 5 clinical findings of infection?
- positive sense RNA virus transmitted by Culex mosquites from birds
- causes encephalitis, viral meningitis, flaccid paralysis, seizures, and coma
Hepatitis C: what is it and how is it transmitted, what are 3 clinical findings of infection, and what are two molecular findings of infection?
- enveloped (antigenic variation) positive sense RNA virus transmitted via infected blood (needles/blood transfusions) that lacks proofreading exonuclease activity in the 3-5’ direction, making it prone to mutation
- causes hepatitis, jaundice (60-80% develop chronic infection), liver cirrhosis (hepatocellular carcinoma)
- ALT elevated during acute stage (falls after 6 months) and is associated with cryoglobulinemia (IgM precipitate)
Togaviruses (Eastern/Western/Venezuelan/Rubella): what is it and how is it transmitted, what does it typically present with, and how is the adult form different from the congenital form?
- enveloped positive sense RNA virus that are arthropod-borne (arboviruses) commonly transmitted via mosquitoes and cause encephalitis
- rubella is transmitted via respiratory droplets and presents w/tender post auricular/occipital lymphadenopathy, maculopapular rash that spreads from face inferiorly
- TORCH (spread congenitally) causing patent ductus arteriosus, congenital cataracts, sensorineural deafness, and blueberry muffin rash/jaundice
adults rubella infection causes: arthritis of knees/wrists/fingers
one long polyprotein that gets cleaved
Coronavirus: what is it and what are two clinical findings it can cause?
- helical enveloped positive-sense RNA virus
- causes the common cold and upper respiratory tract infections that cause MERS and SARS
Human Immunodeficiency Virus: what is it and what cells does it infect, and what does gag, env, and pol encode for?
- enveloped diploid (two copies) positive sense RNA virus that initially infects macrophages, that allow it to infect CD4+ T helper cells (CCR5 early and CXCR4 late)
gag = p24 protein (conical capsule of RNA strand) env = gp41/120 proteins (transmembrane and surface proteins of the envelope) pol = reverse transcriptase (RNA --> DNA)
Human Immunodeficiency Virus: how does it present accutely, what lvls are patients diagnosed with AIDS, and what are two tests used to diagnose HIV?
acute: flu/mono-like symptoms (cervical lymphadenopathy and pharyngitis), fever
- undergoes a latency period that can last up to 10 years (CD4+ < 200 = diagnoses of AIDS or above 200 in presence of AIDS defining illness)
- pts at risk of Diffuse B Cell Lymphoma
- use ELISA to diagnose (anti-HIV Abs) and Western Blot (detects p24 Ag and confirms HIV)
Influenza Virus (orthomyovirus): what is it and where does it replicate, how is it transmitted, and what two Syndromes can it associated with?
- enveloped negative sense RNA virus that is the only RNA virus that replicates inside the NUCLEUS (all others replicate in CYTOPLASM); genomes composed of 8 segments and exhibits antigenic drift and shift
- transmitted via respiratory droplets and can cause pneumonia (more susceptible to bacterial pneumonia during or after flu)
- no aspirin for kids –> Reyes Syndrome
- encephalopathy, fatty liver, hepatic failure
- Guillain Barre Syndrome –> ascending paralysis
What are Antigenic Drift and Shift? (Flu)
Antigenic Drift (why we need new shots each year)
- point mutations in viral genome
- cause Hemagluttinin and Neuraminidase changes
Antigenic Shift (creates new species: PANDEMICS)
- segments of different virus genomes come together
- forms novel genomes w/virulence factor variation
Influenza Virus: what are the protein Hemagluttin, M2, and Neuraminidase responsible for?
Hemagluttinin (HA) - viral entry into host cells
- binds sialic acid residues
- H1/H2/H3 –> determines cell tropism
M2 protein of Flu A = proper pH for viral encoding
Neuraminidase (NA) - cleaves sialic acid residues
- releases virus from host cells
What four viruses are part of the Paramyxovirus family? What do they have in common with each other?
- Measles, Mumps, Parainfluenza, and Respiratory Syncytial Virus (RSV)
- enveloped negative sense RNA virus transmitted via respiratory droplets
Measles Virus: what two proteins does it have, what are 6 clinical symptoms it presents with (CCCKFP), how is its rash characterized, and what is a serious complication of it? (SSPE)
- referred to as Rubeola, possesses HA protein and fusion protein (multinucleated giant cell syncytia) –> give Vitamin A
- presents with cough, coryza, conjunctivits, and Koplik spots (small blue-white spots on cheek mucosa), and fever over 104 degrees; can also cause pneumonia
- maculopapular rash that starts at the face and moves inferiorly (confluent)
- subacute sclerosing panencephalitis (progressive brain inflammation)
Mumps Virus: where does it replicate and what proteins does it possess, and what are two clinical findings of infection?
- replicates in partoid gland (parotitis) and can cause unilateral orchitis (testes inflammation)
- possesses HA protein, fusion protein, and NA protein
- can progress to meningitis
RSV Virus: who does it affect and how, what proteins does it possess, and what two things is it the most common cause of?
- commonly affects infants < 6 mo, infecting their respiratory epithelium via G proteins
- possesses fusion protein
- most common cause of bronchitis and pneumonia in infants
Parainfluenza Virus: what does it cause and what proteins does it possess, what does it show on X-Ray, and what is it the most common cause of?
- cause of croup (Barking Cough) and possesses HA protein, fusion protein, and NA protein
- shows “steeple sign” on X-ray due to subglottic trachea narrowing
- is a common cause of inspiratory stridor
Rabies Virus: what is it and how is it transmitted, where does it spread, and what are 4 clinical findings of infection? (FFE/N)
- bullet-shaped, helical, enveloped negative sense RNA virus commonly carried by bats, skunks, raccoons, foxes that binds to nicotinic acetylcholine receptors (postsynaptic membrane)
- travels retrograde along peripheral nerves to dorsal root ganglia and replicates in the motor neurons
- presents with fever, foaming of the mouth, and encephalitis (see Negri bodies in hippocampal pyramidal nervous tissue and Purkinje bodies)
Ebola virus and Marburgvirus: what are they and how are they transmitted, what are 3 clinical findings associated with infection (PR/HF/HS), and who is at inc. risk of infection?
- helical enveloped negative sense RNA viruses transmitted via primates and bats
- present with petichial rash and fever (hemorrhagic fever) and can lead to hypovolemic shock
- healthcare workers are at high risk for contracting from patients
Hantavirus (PE/H/HF), California encephalitis virus, and Rift Valley River virus (E/S): what are they, how are they transmitted, and what are clinical findings of each?
- enveloped (Golgi body membrane) negative sense RNA viruses whose genome is composed of 3 segments
hantavirus: transmitted via urine/feces/saliva of rodents and can lead to pulmonary edema, hypotension leading to pre-renal azotemia, and hemorrhagic fever
CEV/RVR: transmitted via Aedes mosquito and causes encephalitis and seizures (arboviruses)
Lymphocytic Choriomeningitis Virus: what is it and what does it look like, how is it transmitted, and what are 3 clinical findings of infection? (G/AM/F)
- helical enveloped negative sense RNA viruses (have some positive sense RNA segments) = AMBISENSE; genomes carry two RNA segments and are transmitted via rodents
- appear grainy on microscopy, causes aseptic meningitis and fever (inactivated via heat and irradiation)
Rotavirus (WD) and Colorado Tick Fever (VFM): what are they and how does each present clinically?
- naked double stranded (pos/neg sense) RNA viruses and is comprised, on average, of 11 RNA segments
Rotavirus: watery diarrhea caused by NSP4 enterotoxin (inc. chloride permeability); peaks in winter w/children (#1 cause of severe child diarrhea)
Colorado Tick Fever: vomiting, fever, myalgias
What 6 viruses make up the Herpes Virus Family? (HSV, EBV, CMV, VZV, HHV-6/8)
Herpes Simplex Virus 1 and 2, Epstein-Barr Virus, Cytomegalovirus, Varicella-zoster Virus, HHV-6 (Roseola), and HHV-8 (Karposi Sarcoma)
Herpes Simplex Virus Type 1 and 2: what is it and what does it look like (3 - CDH), where does HSV1 and HSV2 lie at, and how does each present clinically?
- enveloped, DS, linear DNA viruses that produce Cowdry bodies in infected cells and have a “dew drop on rose petal” appearance (Tzank Smear) and can cause Herpetic Withlow (finger lesions) and target lesions on back of hands and feet
HSV1: lies dormant in trigeminal ganglia; causes gingivostomatitis w/herpes labialis (cold sores) around lips, keratoconjunctivitis, and can cause hemorrhagic temporal lobe encephalitis (#1 cause of sporadic encephalitis)
HSV2: lies dormant in sacral ganglia; causes inguinal lymphadenopathy and aseptic meningitis in adults and kids
Epstein-Barr Virus: what is it and what do infected cells look like, what are 4 clinical findings of infection (F/L/S/P), and what are 4 cancers that infected patients are at inc. risk of contracting?
- DNA virus that is primarily transmitted through saliva that remains latent in B cells; presents with peripheral lymphocytosis (DOWNEY CELLS)
- causes fever, post. cervical lymphadenopathy, splenomegaly, pharyngitis (tonsilar exudate)
- inc. risk of developing Hodgkins/non-Hodgkins (reed Sternberg Owl Eyes), Burkitt lymphoma (large jaw lesions), nasopharyngeal carcinoma, oral hairy leukoplakia
How does the Epstein-Barr Virus initiate infection? What happens if they are treated with penicillin? What should infected patients avoid?
- envelope glycoprotein binds to the CD21 membrane protein of B cells
- develop a maculopapular rash if treated with penicillin or amoxacillin on accident
- avoid contact sports so they don’t rupture their spleens
Cytomegalovirus: what is it and what does it look like, what are 6 congenital symptoms, 1 transplant symptoms (CP), and 3 immunocompromised symptoms (RECitis)
- DNA virus that stays latent in mononuclear cells that have “owl eye” inclusions upon visualization, monospot test negative
congenital: blueberry muffin rash, jaundice, hepatosplenomegaly, sensorineural hearing loss, ventriculomegaly, periventricular calcifications
- most children w/congenital are asymptomatic
transplant pts: Cytomegalovirus pneumonia
immunocompromised: (CD4 < 50), retinitis (Pizza Pie retinopathy), esophagitis (single, deep, linear ulcer), colitis
What is Cytomegalovirus the #1 cause of? How do you tell it apart from EBV?
- sensorineural hearing loss
- also #1 congenital viral infection
- use monospot test (test will be negative for Cytomegalovirus but positive for Epstein-Barr Virus)
Varicella-zoster Virus: where does it remain latent and what does it look like, what does it normally cause in children and immunocompromised (P/E), and what is Shingles?
- enveloped DNA virus that is transmitted by respiratory droplets and remains latent in dorsal basal ganglia; lesions look like “dew drops on rose petal”; Tzank smear for diagnosis
- causes chickenpox: fever, headache, vesicular lesions at different stages; immunocompromised: inc. risk of pneumonia and encephalitis
- Shingles (reactivated) –> dermatomal distribution, extremely painful (postherpetic neuralgia) and vision loss if reactivated in V1 (opthalamic)
- TORCH (o = others)
HHV-6 (roseola): what is it and who does it affect, and what are 3 clinical findings of it? (F/F/LR)
- DNA virus that infects CD4+ cells (immunocompromization); commonly affects children age 6 mo - 2 yrs
- fever lasting 4 days, febrile seizures in children, diffuse lacy body rash (spares face)
HHV-8 (Kaposi Sarcoma): what is it and what does it look like, and what are 3 clinical findings of it? (V/P/PL)
- DNA virus that is an AIDS-defining illness causing violet lesions of nose, extremities, mucosa
- causes vascular proliferation (VEG-F disregulation), lesions in GI tract/hard palate. primary effusion lymphoma (B cell infection)
JC and BK polyomavirus: what are they, how does JC present (ML/MBL/DD), and how does BK present (N/HC)
- naked, DS circular DNA viruses
JC: progressive multifocal leukoencephalopathy in immunocompromised patients (CD4+ < 200); non-enhancing multifocal brain lesions; demyelinating disease
BK: nephropathy (transplant/immunocomp), hemorrhagic cystitis
Human Papillomavirus: what is it and what does it look like, and what are the clinical presentations of HPV 1-4, HPV 6/11, and HPV 16/18/31/33?
- naked DNA virus with koilocytes (large cells w/dense wrinkled nuclei)
HPV 1-4: verruca vulgaris (cut. warts on kid hand/feet)
- physical contact
HPV 6/11: laryngeal papillomatosis & anogenital warts (condyloma accumulata)
- sexual contact
HPV 16/18/31/33 = anogenital and squamous cell cancer
Parvovirus B19: what is it and how is it transmitted, and what is its clinical presentation in children, adults, and congenitally?
- naked SS DNA virus that is the smallest DNA virus and is transmitted by respiratory droplets (TORCH)
- causes “Slapped Cheek Syndrome”: rash starts on face and moves inferiorly
- causes arthralgia, arthritis, and edema in adults
- causes hydrops fetalis congenitally
Adenovirus: what is it and what is it the most common infector of, how is it transmitted and what two places are known to see outbreaks, and what are 3 clinical mainfestations of infection? (T/HC/PE)
- naked DNA virus that is most common infector of adenoids/tonsils; transmitted by respiratory droplets, fecal-orally (commonly affects kids)
- outbreaks occur in public swimming pools and military barracks
- causes tonsilitis, hemorrhagic cystitis, and pink eye
Smallpox, Cow Pox, Molluscum contagiosum virus: what are they and what do they look like, where do they replicate at, and what does each virus cause?
- DNA viruses that make their own envelope and can replicate in the CYTOPLASM (Guarnieri bodies); have “dumbbell-shaped” core and are the LARGEST DNA virus
Smallpox: lesions all the same (vs Zoster lesions),
Cowpox: contact w/infected udders
MCV: flesh-colored, dome-shaped, umbilical skin lesions (trunk of kids)
Hepatitis B Virus: what is it and where does it replicate, what is the rate of chronic infection in neonates and adults, and what are 5 clinical presentations of infection? (PN/R/A/CKD/MG)
- enveloped, partially DS DNA virus that undergoes both Nucleus and Cytoplasm replication; transmitted via sexual contact, blood transfusion, or vertically (TORCH; “O”)
- 90% of neonatal infections become chronic, while 10% of adult infections become chronic
- causes polyarteritis nodosa (chronic vasculitis), rash, arthralgia, chronic kidney disease, and membranous glomerulopathy
- major risk of liver cirrhosis and hepatocellular carcinoma
ALT levels of Hepatitis B (acute and neonatal)
Acute: ALT lvls rise and fall (once symptomatic phase is over)
Neonatal: ALT lvls are normal
viral hepatitis = ALT>AST
Hepatitis B Serological Markers (SECES): how will people with Hep B vaccine test?
- HBsAg - (surface Ag): first marker of active infection
- HBeAg - (envelope Ag): active replication
- high infectivity
- Anti-HBc Ab - maybe only marker during window period
- Anti-HBe Ab - low transmissibility
- Anti-HBs Ab - recovery from infection or immunization
**people with HepB vaccine will be positive for Anti-HBs and negative for Anti-HBc and Anti-HBe
Hepatitis D: what is it and what does it look like, and how can it be transmitted with HepB?
- enveloped negative sense RNA virus that only propagates in the presense of Hepatitis B
- circular and single stranded that requires HBs-Ag to be infectious
- can be coinfected (transmitted at same time as Hep B) or superinfectious (transmitted AFTER pt has contracted HepB = WORSE PROGNOSIS)
