virus818 Flashcards
Virus:
-either dna or rna not both
-obligate intracellular parasite
-no cell wall, no ribosomes, no growth on media
Capsid: Protein coating genome; made of capsomer
Capsomer: structural protein units make up capsid
Nucelocapsid:
-Nucleic acid and capsid
Envelope:
outer membrane around capsid, aids in attachement to host
Virion:
mature virus particle with a nucleic acid core surrounded by a protein coat, w/wout an envelope
Peplomer: spike protein
Bacteriophage, phage:
-virus that infects and replicates in bacteria/archaea
-proteins that encapsulate DNA/RNA, replicate in bacteria after injecting their genome in their cytoplasm
Viral Diseases
Respiratory:
-flu,RSV, parainflu
Gastroenteritis
-noro, rota, adeno
Vesicles/lesions
-HSV, VZV/shingles
Cervical
-HPV
Meningitis
-HSV, entero
Immunocompromised
-CMV, EBV, HSV,
Hepatitis
-HAV, HBV, HCV
HIV
Coronavirus
1.)MERs
-arabian, camels
-respiratory failure from contact
SARS
-china, EIA/molecular
SARS-CoV2
-bat, china
-respiratory droplet
nasopharygeal swab
-RNA molecular and antigen assay
-Ab detection
Viral diagnostic
1.)Direct detection:
-electron microscope
-light miscrope for inclusion bodies
-Fluorescent microscope, DFA(ab detects ag)
-PCR/nucleic acid probes
-Antigen/EIA: flu, rsv, rotavirus
2.)Virus isolation
-animal inoculation
-embryonated egg inoculation
-shell vial centrifugation
-in vitro cell culture: CPE
-cytopathic effects
-rounding, swelling, shrinking of cells
3.)Serology
-sera a week apart, 4fold rise in IgG diagnostic of infection
-ELISA: HepB blood donor
-EBV (heterophile, Monospot)
-Hep (ab markers)
-HIV, HTLV
Cell culture:
-Primary: from animals, isolates most viruses
-Diploid/finite: can only use one type of cell culture,
-Continuous: malignat/Hep2, HSV, RSV, adeno
Collect: 3 to 7 days w/in onset symp, viral shedding highest in early infection, decreases a few days after acute symptoms
-aspiration of secretions best
-swabs dacron/rayon
-VTM: Hanks balanced salt sln w/antibiotics
4C if not w/in 1 hr
(not blood)
-60C if not w/in 24hrs
tranport on dry ice
What is the most common format for viral isolation?
Tube monolayer cell culture is the most common format for viral isolation. Tissue is minced and treated with an enzyme to disperse individual cells further. The cells are seeded onto a surface to form a monolayer in a tube or flask. Leukocyte culture, organ culture and laboratory animals are primarily reserved for specialized and research laboratories.
Three potential viroterrism agents
echo viruses called
ebola
small pox
hanta (RNA, rodents)
Enteric cytopathic human orphan virus
Cause of gastroenteritis kids winter
Rotavirus
Infection can be reactivated with latent infection with
Herpesviridae
two ways to inactivate viruses
10% bleach, 3-10min
2% glutaraldehydge, 1-10min
DNA viruses
Adeno
HepB
Herpes 1/2
CMV
EBV
VZV
Parvo
Papillo (HPV)
Pox (small pox)
Herpes viruses are RNA or DNA?
name some
Herpes: DNA
HSV1/2,6/8
VZV
EBV
CMV
Hepadnavirus
Hep B
Papillomavirus
HPV
HSV 1 is oral or genital
HSV 2 is oral or genital
- oral
- genital
Common RNA
-Coronavirus
-Orthomyxovirus/flu ABC
-Picornavirus/Rhinovirus: cold
-Calicivirus/Noro: gastroenteritis in US
-Reovirus/Rotavirus gastroenterotis in kids
-Retrovirus: HIV, HTLV
-Hep A
-Paramyxo: Mumps/Measles, RSV kids
-Rhabdo/Rabies
…
orthomyxoviruses
flu a,b,c
Flavi-viruses
Arbovirus, dengue, yellow
WN, St.luis
HCV
Rhabdoviruses
Rabies
Retro viruses
HIV, HTLV
Reovirus
Rotavirus
Paramyxovirus mostly kids, elderly, immunocomp
Measures, mumps
Paraflue
RSV
HMPV
PCR
Ligase chain reaction
strand displacement amp all are nucleic acid amplification teq
not flow
Lipase chain reaction:
Nucleic acid amplification
The ligase chain reaction (LCR) is a method of DNA amplification. The ligase chain reaction (LCR) is an amplification process that differs from PCR in that it involves a thermostable ligase to join two probes or other molecules together which can then be amplified by standard polymerase chain reaction (PCR) cycling
Strand Displacement Amplification (SDA): Nucleic acid amp
Strand Displacement Amplification (SDA) is an isothermal, in vitro nucleic acid amplification technique
Histoplasma, Crypto, Cocci, Blasto, Geotrichum all produce this kind of mycoses
systemic
Dermatophytes, Microsporus produces this kind of mycoses
cutaneous/skin
Sporotrichum, Chromoblasto make this kind of mycoses
subcutaneous
Colorful bodies are found in which fungi
Chromoblastomycosis
Fungus of skin/hair/nails seen under woods lamp
Dermatoophytes
branching, intertwining of molds…
branching hyphae grows downwards from anchor…
branching, intertwining of molds…mycelium
branching hyphae grows downwards from anchor…rhizoids
asexual stage of yeasts…
Asexual reproductive spore of fungi…
asexual stage of yeasts…
blastocondia
Asexual reproductive spore of fungi…conidia
3 dermatophytes, cutaneous
microsporum
trichophyton
epidermophyton
Dermatophyte
macroconidia:
thick walled, multi septate usually in kids
microconidia: few/absent, club
Microsporum
Micro, kids, macro
Canis: dog
Anthropophilic: humans
Dermatophyte
Microconidia:
predominant
adults
Trichophyton
Adults, Only one of three with microconidia
Dermatophyte
Macroconidia:
club shaped
Microconidia:
absent
Epidermophyton-club macro
Fungi in water damaged areas, mycotoxins
Stachybotrys
Fungi such as Rhizopus/Mucor, nonseptate, lid lifters
Mucormycosis
Infective form of dimorphic fungi for lab
Best temp, days for mycology
hyphal which is the long branching w/nuclei
30C, 30 days
Two ingridients used in Mycosel SDA
chloram-phenicol
cyclo-heximide
BHIA…
For…
Brain Heart infused agar for fastidious fungi
Germ tube+
Pseudohyphae +
Chlamydospores on cornmeal
thrush
Candida albicans
Lung to brain, meningitis, systemic, capsule/mucoid
bird/bat droppings
Urea and birdseed agar used for
C.neoformans
Trichoophyton that is ureas po and penetrates hair shaft
T.mentagrophyte
Trichophyton that makes red pigment on dermatophyte medium
T. Rubrum
R=red
Sclerotic bodies, subcutaneous
Colored
Chromoblastomycosis
Systemic mycoses, true yeast
India ink prep, serology of CSF, HIV
wide refractive capsule
Cryto. neo
Three fungi with yeast in tissue phase of humans
H.capsulatum
(blastospores, intracellular in phagocytes, tissue)
B.dermatitidis (Broad based)
-B for broad based
Coccidiodies immits
(thick walled spherule with endospores in tissue, keeps them alive in desert)
dimorphic, intracellular mononuclear cells
yeast tissue phase
yeast blastospores
*Mycelial: thick walled tuberculate macrocondia
Darlings disease
Chix house,pidgeou coup
H.capsulatum
Capsulatum is a darling, she’s tuberculate w/chlamydospores and lives in phagocytes
Yeast with thick walled spherule with endospores in tissue
Mycelial: Barrelshaped arthroconidia with alternating or spaces
Valley fever
Coccidioides immitis
Dimorphic,
Yeast: cigar shaped
(tissue phase) at 37C,
Mold:
flower, rosette heads
Roses
Rose handlers disease, subcutaneous
S.schenkii
Schenckii the rose gardener smokes cigars while growing flowers of conidia
dimorphic, broad based yeast, yeat in tissue
gilchrist disease
inhale conida/hyphal soil,wood,waterways
conidia at tips (lolipops)
Blastomyces dermatitidis
Gilchrist the farmer has dermatitidis and eats lollipops with broad yeast
Latin american agriculture
Mariners wheel
dimorphic
Yeast mother surrounded by daughter buds
mycelial: lolipops
No NAT
Paracoccidioides
brasiliensis
There’s lollipop mold and mariners wheels in brasil
San Jouqin valley fever, hot dry alkaline soil
lab hazard, inhale arthroconida
Yeast thick wall spherules endospores
Mycelial barrel shape arthroconida/empty spaces
sealed plates BSC 3
NAT
Coccidioides immitis
Cocci immitis lives in the valley where there’s barrels w/spaces and spheres with endospores
ascospores
sexual propagules of ascomycetes
blastoconidia
Yeast: asexual reproduction (budding)
arthroconidia
fungal spore produced by segmentation of preexisting fungal hyphae
chlamydospores
thick walled large resting spore, asexual
Name of yeast for Tinea versicolor
Bottle shaped budding
Malassezia furfur
Opportunistic infection in AIDs, can’t be cultured
Pneumocystis jiroveci
Two lid lifters, lab contaminant, zygomycetes
Rhizopus
Mucor
Farmers lung, Hyaline
aspergillus
Fonsecaea and phialophora are two types of
Chromoblastomycosis
Where does the fungal infection Onychomycosis occur?
a.
Blood
b.
Hair
c.
Nails
d.
Skin
Nails
Onychomycosis, which is infection of the nails, is most often caused by dermatophytes but also may be the result of infection by other fungi.
What fungi can generally be divided into two broad groups based on the appearance of the colonies formed in the clinical laboratory?
Question 182Answer
a.
Cutaneous and subcutaneous
b.
Septate hyphae and aseptate hyphae
c.
Systemic and superficial
d.
Yeast and mold
Yeast and molds are the two groups’ fungi and are separated into based on colonies formed. Fungi can be further divided based on the infections produced and microscopic appearance. Yeasts form a smooth, creamy, bacteria-like colony. Molds have a fuzzy or woolly appearance due to formation of mycelia.
What test depends on Candida albicans being able to produce hyphae-like extensions from their yeast cells when placed in 0.5 mL of sheep or rabbit serum and incubated at 35 °C for no longer than three hours?
Examine under low power magnification. This allows an early identification of the most common and important yeast pathogen. Time of incubation is critical since other species produce a similar looking tubule with extended incubation.
Why are systemic mycoses historically grouped together?
Question 197Answer
a.
They are opportunistic and primarily occur in immunocompromised patients, such as HIV
b.
They are present in the keratinized tissue of humans and animals; identified as dermatophytes
c.
They occur in patients from the same geographic area
d.
They are shared characteristics, such as mode of transmission, dimorphism, and dissemination
They are shared characteristics, such as mode of transmission, dimorphism, and dissemination
Systemic mycoses are mostly caused by inhalation of the conidia, are dimorphic (able to grow in the mold form or in the lab in their yeast form) and disseminate to sites far removed from the portal of entry in a patient.
Where are KOH solutions of 10 – 20% useful for the identification of fungi?
Question 200Answer
a.
Blood and body fluids
b.
Cerebrospinal fluid
c.
Feces, vomit, and saliva
d.
Skin, hair, and nails
Skin, hair, and nails are useful for the identification of fungi. Thin slices of tissue and mucoid specimens may be treated with a solution KOH to break down the proteinaceous material while leaving the fungal elements intact for identification.
