Virology Flashcards
Viral Specimen Collection
Collect during heavy viral shedding
Swabs and tissue in VTM (viral transport media), Dacron or Rayon swabs - no VTM with body fluids
Do NOT use calcium alginate (inhibits viral replication)
Culture ASAP or store at 4 deg, or at 70C if >4 days. Do NOT freeze at -20C, will crystallize and kill the virus
Adenovirus
Respiratory disease, conjunctivitis, gastroenteritis, obesity/adipogenesis
Pneumonia in US, gastroenteritis in children
Shed by respiratory and eye secretions in acute infection
Shed in stool and urine during convalescence
dsDNA, non-enveloped, icosahedral
Hepatitis B
Cirrhosis and Hepatocellular carcinoma
Clay colored stool, dark urine
Transmission: blood-blood (parenterally), or sexual route due to blood contact
Hepadnaviridae family
Partially dsDNA, enveloped
HSV (or HHV) I & II
Most common cause of corneal infection and fatal Encephalitis in US
Tzanck smear
Oral herpes/genital herpes
Herpesviridae family
Diagnosed with IF from lesion specimen
Varicella-zoster virus (VZV)
Chickenpox & Shingles
Large multinucleated cells on Tzanck smear
Specimen of choice: scrapping off the lesion
Epstein-Barr Virus (HHV 4)
Infectious mononucleosis (mono) in 15-24 yo
Burkitt lymphoma
Hodgkin’s lymphoma - Reed-Sternberg cells (owl eyes)
Nasopharyngeal carcinoma
Multiple sclerosis
Cytomegalovirus (CMV)
Urine = most common specimen
Congenital infection from mother —> baby
Diagnosis: PCR
Human papillomavirus
Skin warts
Cervical cancer, oropharyngeal cancer and penile cancer
Cervical swab/scraping
Koilocytes
Parvovirus B19
5th disease, Erythema infectiosum- slapped cheek (rash spreads to trunk and limbs)
Flu-like symptoms
Self-limiting
Naked ssDNA, smallest DNA virus
Poxvirus
Variola virus: smallpox
Largest of all viruses
dsDNA
Dengue virus
Dengue fever (mild)
Dengue hemorrhagic fever (bleeding in organs)
Aedes aegypti
Flavivirus family
Yellow virus
Vector: Aedes aegypti
Reservoir: Monkeys, or human to human
Flavivirus family
St. Louis Encephalitis
Vector: Culex mosquito
Circulates in birds
Midwestern and Southern states, summer
Milder in children than adults
Humans are dead end host (cannot infect human to human)
Flavivirus family
West Nile Virus
Vector: Culex mosquito
From birds - needs avian host to replicate
Leading cause of vector born fever in the US
Found in body fluids and tissues
Mother—> baby, blood transfusion or organ donation
Flavivirus family
Zika
Vector: Aedes species
Guillain-Barré syndrome (trouble walking due to myelin sheath damage)
Microcephaly and neurological deformities in fetus
Flavivirus family
Bunyaviridae, Hantavirus
Vector: rodent. From rat poop - more likely to inhale in drier states
Kidneys and lungs
Hemorrhagic fever with renal syndrome (HFRS)
Old world Hanta virus (more severe, Europe and Asia)
New world Hanta virus (America) - hantavirus pulmonary syndrome (HPS)
Hepatitis A
Self-limiting
Transmission: fecal-oral
Does not cause chronic liver damage
Hepatitis C
Only Flaviviridae that is not vector borne
High mortality rate
50% disease patients are chronic carriers, 30% of those can develop cirrhosis
High ALT
Transmission: blood contact
(Same symptoms and signs as hep B)
Diagnosed by EIA (high false pos rate so confirm with PCR)
Influenza
Group A: classified by hemagglutinin and neuroaminidase glycoproteins
- only group with known animal reservoirs (pig, bird)
Antigenic drift (RNA replication errors, results in seasonal flu strain changes) - not a major change
Antigenic shift (major change to surface antigens causing a new H or N antigen) - results in pandemic flu outbreaks like Spanish flu
- Group A: undergoes both drift and shift
- Group B: drift
- Group C: neither one, relatively stable
- Group D: only affects cattle
Influenza complications
Otitis media
Primary viral pneumonia
Secondary pneumonia (S. pneumo, S. aureus, H. influenzae)
Reye’s syndrome: acute encephalopathy, fatty liver
Guillain-Barre Syndrome: demyelination of motor nerves —> paralysis
Influenza diagnosis testing
ELISA - distinguishes between influenza A and B
PCR testing, Biofire, cepheid
Parainfluenza
Most important respiratory disease is within 2 first years of life, along with RSV
PCR with nasopharyngeal swab
Symptoms: rhinitis, pharyngitis, laryngotracheitis, bronchiolitis, pneumonia
Morbillivirus
Measles (Rubeola)
Maculopapular rash on head and trunk
Koplik spot lesions on oral mucosa
Highly contagious, through aerosol droplets
Diagnosis: IgM presence of cell culture on PMK cells (primary macaque kidney)
Rubulavirus
Mumps
Bilateral (or unilateral) swelling on parotid glands (Hamster Face)
Transmission: saliva
EIA and IF testing
Rubivirus
Rubella (German measles)
Mild febrile disease with erythematous, maculopapular, and discrete rash and lymphadenopathy
Similar to measles (can be misdiagnosed)
Transmission: airborne droplets
Affects pregnant women and fetus: Congenital Rubella Syndrome (CRS) - can affect almost everything on baby’s body. More damage the earlier into pregnancy
Poliovirus
1/200 will have lasting CNS effects since CNS has low cell numbers
Poliomyelitis - paralysis
Diarrhea (GI tract) and flu symptoms
From Enterovirus genus
Coxsackie virus
Hand, foot and mouth disease - common in < 5 yo
Contagious, spreads at daycares and schools
Rarely meningitis and encephalitis
Enterovirus
Respiratory Syncytial Virus (RSV)
Causes croup (URT), bronchitis, interstitial pneumonia
Severe lower respiratory disease in children
Nosocomial spread
Transmission: fomites and large particle droplets
Rhabdovirus
Rabies
Flu-like with hallucination, hydrophobia, excessive salivation, irritability, anxiety —> coma, death
Mostly from dogs
Negri bodies
Enveloped RNA rod shaped virus
Coronavirus
Common cold
Largest RNA virus
Coronaviridae
Biofire test for various coronavirus
Pleomorphic morphology
Specimen processing for Coronavirus
Real time rtPCR
antigen test FIA
Cepheid
Biofire
Nasopharyngeal or oropharyngeal swab in VTM, saliva
Short term immunity due to antigenic changes in Spike protein
Rotavirus
Naked dsDNA, resembles a wheel (rota-= wheel)
Gastroenteritis in children
Fecal oral route
Fillviridae
Ebola virus
High mortality rate
Ebola hemorrhagic fever - fever, chills, myalgia, anorexia, sore throat, vomiting, diarrhea
From infected humans and primates, possibly from bats but not known
Sub-Saharan Africa
Rhinovirus
Common cold
Congestion, sneezing, sore throat, cough
Self-limiting
Transmission: inhalation of aerosols, fomites, contact with secretions
Infects nasal epithelial cells
Retroviruses/Retroviridae
ssRNA, enveloped
Reverse transcriptase - makes proteins by converting RNA —> DNA —> various RNA like mRNA, tRNA, etc
Associated with cancers, immune system disorders, degenerative neurological disorders, leukemias, AIDs
HIV
Acute infection:
- Flu-like symptoms
- high mutation rate and high reproduction rate prevents complete clearance by immune system
Latency period:
- virus infects T cells and macrophages/monocytes. Infected cells show no signs of infection so can go unnoticed by immune system
- increased T cells and dendritic cells infected = immune system falls apart
HIV screening and confirmation
Screening: EIA - identifies HIV 1 and 2, p24
(+) = colored well, retest in duplicate
(-) = no further testing
Confirmatory: Western Blot or IF
Western Blot - most important antibodies are against:
gp24, gp120, hp41
Karposi’s Sarcoma
Caused by AIDS
Cancer of lymph vessel and blood vessel cells
Associated with HHV 8 virus
HTLV I (Human T-lymphotropic virus)
T cell leukemia
HTLV II (Human T-lymphotropic virus)
Hairy cell leukemia
HIV testing
Serology
Which virus has negri bodies?
Rhabdovirus (Rabies)
Which virus has koilocytes?
HPV
Which viruses have common cold as a symptom?
Coronavirus
Rhinovirus
Which viruses have Guillain-Barre Syndrome?
Zika
Influenza
Which virus has a rodent as a vector?
Hantavirus (Bunyaviridae)
Which viruses have hemorrhagic fever?
Hantavirus
Filoviridae (Ebola)
Dengue virus
Leading cause of vector borne fever in the US
West Nile virus
Only Flaviviridae that is NOT vector borne
Hepatitis C
Largest of the RNA viruses
Coronavirus
Which viruses have flu-like symptoms?
Poliovirus
Parvovirus
HIV (retrovirus) in acute stage
Infectious mononucleosis viruses
EBV
CMV
Papillomaviridae family for:
HPV
