Viruses Flashcards
(94 cards)
1
Q
What is the taxonomy of HPV? Family, Genus, and Species
A
Family: Papovaviridae
Genus: Papillomavirus
Species: Human papilloma virus
2
Q
Viruses within genus Papillomavirus cause what symptoms?
A
Warts and cancer (cervical, vaginal, anal, penile, and oral). Frequently STDs.
3
Q
What is the structure of HPV? Capsid, Genome, Envelope
A
Capsid: Icosahedral
Genome: dsDNA, circular
Enveloped: No
4
Q
How is HPV grouped? What are two examples?
A
Predilection for type of tissue they infect: 1. Cutaneous HPV (growths on epithelium of skin) 2. Mucosal HPV (growths on mucous membranes)
5
Q
What is the mechanism by which the virus enters and develops symptoms?
A
Enters basal layer thru skin breaks and replicates, stimulating hyperplasia–> thickening of skin (acanthuses)–> warts (3-4 mos)
*Regress w/in 2 yrs but can recur
6
Q
***What is the most common STD in the US?
A
***Papillomavirus
7
Q
What is the epidemiology of HPV?
A
Direct contact and infection of live skin thru broken skin.
Fomites, surfaces, bathroom floors, pools
8
Q
Which HPV types cause laryngeal papilloma and conjuctival papilloma?
A
HPV type 6 and 11
9
Q
Which HPV types cause oral papilloma
A
HPV type 6, 11, 2, and 16
10
Q
Which HPV types cause focal epithelial hyperplasia
A
13, 32
11
Q
Which HPV types cause cervical cancer?
A
16, 18, 31, and 45
12
Q
What is the clinical syndromes for conjunctival papillomas?
A
Non-malignant, mushroom-shaped growths on eyelid. Most benign and asymptomatic wo associated conjunctivitis or folliculitis. (6,11)
13
Q
What areas of the mouth are frequently involved in oral warts caused by papillomavirus?
A
Can occur anywhere but frequently hard/soft palates or uvula.
14
Q
What are the 2 forms of lesions that form as oral warts?
A
- Exophytic warts: Dome-shaped papules or have hyperkeratosed fronds. Appear individually or in groups.
- Focal epithelial hyperplasia: (Heck’s disease) multiple nodular lesions in the mouth (13,32)
15
Q
Which HPV types cause genital warts? How is it generally contracted?
A
6 and 11. Sexual contact
16
Q
How is the mechanism by which HPV causes cervical cancer?
A
HPV DNA integrates into host cell DNA and cell cycle control disrupted (16, 18, 31, 45)
17
Q
What are the two methods in which HPV is diagnosed in the lab?
A
- Pap smears: to observe koilocytotic (vacuolated cytoplasm) squamous epithelial cells
- In situ DNA probe analysis, PCR and Southern blotting to determine genotypes
18
Q
How are HPV warts typically removed?
A
Surgical cryotherapy, electrocautery or chemical (Podofilox) but still recurrent
19
Q
What two class of drugs are used against papillomaviral infection?
A
Interferon and Imiquimod (stimulate host immune system)
Cidofovir (nucleotide inhibitor)
20
Q
What are two specific vaccines used against HPV?
A
- Gardasil: Protect against 6 & 11 (genital warts); 16 &18 (cervical cancer)
- Cervarix: 16 &18
21
Q
What is the taxonomy of Adenovirus? Family, genus, species
A
Family: Adenoviridae
Genus: Mastadenovirus
Species: Human adenovirus
22
Q
What is the structure of adenovirus? Capsid, genome, and envelope
A
Capsid: icosahedral
Genome: dsDNA, linear
Enevelope: No
23
Q
What is the most common disorders associated with adenovirus?
A
Upper respiratory tract (URT) infections, conjunctivitis, hemorrhagiv cystitis, and gastroenteritis.
24
Q
***What is the most common cause of viral conjunctivitis?
A
Adenovirus (children & military)
25
Where does adenovirus infect?
Epithelial cells lining respiratory tract and enteric organs
26
How is adenovirus spread?
Aerosol, close contact, fecal-oral routes to infect oropharanyx. Finger to eye, contaminated water. Can be latent in lymphoid tissue.
27
What is the histology of adenovirus-infected cells?
Dark basophilic nuclear inclusions: accumulation of DNA, proteins, and capsids.
28
What is the epidemiology of adenoviruses?
Stable in environment and easy to spread by fomites. Resistant to drying, detergents, GI secretions (acid & bile) and mild chlorine.
Serotypes 1-7: most common; 4-7: military
29
What are the clinical syndromes of Acute Febrile Pharyngitis and Pharyngoconjunctival Fever?
Pharyngitis that mimics strep throat: nasal congestion, cough, coryza (URT inflammation, head cold), malaise, fever, chillds, and headache 3-5 days.
CONJUNCTIVITIS often accompanies pharyngitis
30
What are the clinical syndromes of Conjunctivitis and Epidemic Keratoconjunctivitis (EKC)?
Adenovirus infection causes mucosa of palpebral conjunctiva to become nodular and both conjunctivae (palpebral and bulbar) are inflamed.
31
Where is a common source of Adenovirus-related conjunctivitis outbreak?
Swimming pools
32
What are the clinical syndromes for Acute Respiratory Distress Syndrome (ARDS)?
An acute, severe injury to most or all of both lungs. Often require mechanical ventilation due to respiratory failure.
33
Is ARDS a specific disease?
Not a specific disease, it is severe, acute lung dysfunction associated with variety of diseases (pneumonia, shock, sepsis, or trauma).
34
What are clinical syndromes for Atypical Pneumonia?
Community acquired pneumonia characterized by extreme fatigue and nonproductive gough with pulmonary infiltrates.
35
What are clinical syndromes for Gastroenteritis and Diarrhea?
Serotypes 40-42: enteric adenoviruses responsible for infant diarrhea. Rarely cause fever or respiratory tract infections.
36
What are methods by which to diagnose adenovirus in the lab?
Culture from throat infections (not diarrhea)
| Immunoassays, PCR, and DNA probe analysis
37
What are treatment and prevention plans for adenovirus?
None. Must run course.
38
What is the taxonomy Herpesvirus? 1 Family and 3 Subfamilies
Family: Herpesviridae
Subfamilies: Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae
39
Which species are part of the Alphaherpesvirinae?
HHV1 (Herpes Simplex Virus 1)
HHV2 (Herpes Simplex Virus 2)
HHV3 (Varicella-Zoster Virus)
40
Which species are part of the Betaherpesvirinae?
HHV5 (Cytomegalovirus)
HHV6
HHV7
41
Which species are part of the Gammaherpesvirinae?
```
HHV 4 (Epstein-Barr Virus)
HHV 8
```
42
What is the structure of Herpesvirus? Capsid, genome, and enveloped
Capsid: Icosahedral
Genome: dsDNA, linear
Enveloped: Yes
43
How many herpes viruses cause disease in humans? And of them, how many are relevant to dentistry?
8 cause clinical disease, 6 relevant to dentistry (HHV1-HHV5; HHV8)
44
***True or False:
| All herpes viruses have capacity to persist in host indefinitely in the form of episome.
***True (for LIFE)
45
What are the 3 disease phases of human herpes viruses?
1. Primary infection- (virus replicating, asymptomatic, but infectious)
2. Latency- (control of virus, but not cleared)
3. Reactivation- (reactivation, replication, infectious)
46
What 3 factor influence severity of primary infection?
1. Age
2. Site of infection (brain and system dangerous)
3. Immunocompetence (T-cells)
47
Is the clinical disease during reactivation same as what occurred during primary infection? Why?
No, virus may have establish latency in cell type different from cell initially infected.
48
***What is an example of a type of herpes virus that is different in clinical disease when reactivated from primary infection?
***Varicella-Zoster Virus (VZV)
Primary infection: Chicken pox
Reactivated: Shingles
49
What elements of the herpes virus help initiate replication?
Proteinaceous tegument layer btwn capsid and envelope: contains viral proteins and enzymes.
50
What factors of the herpes virus helps inhibit clearance by immune system?
Some of its surface glycoproteins bind the Fc portion of IgG or C3 of complement system.
51
How is the herpes simplex virus (HSV-1,2) contracted?
Direct contact (oral or genital). Initially infect mucoepithelial cells then establish latent infection of innervating neurons.
52
Where is the most common sites of inoculation with HSV-1? HSV-2?
HSV-1: oral mucosa
| HSV-2: genital mucosa
53
How does HSV affect immunocompetent individuals differently from immunocompromised ones?
Immunocompetent: rarely cause viermia
| Neonates and immunocompromised: herpetic encelphalitis (teratogenic organism)
54
True or False:
| HSV-1 and HSV-2 are specified and localized and highly distinguishable.
False
| Both can cause oral herpes and are clinically indistinguishable.
55
What are the clinical syndromes of Herpetic gingivostomatitis?
HSV-1: Occurs mostly in young children. Sores on lips, gums, tongue, and cheeks. Red, swollen gums. Self-limiting. Reactivation results in cold sores.
56
What are clinical syndromes for Herpes labialis?
aka Cold sores. Reactivation of HSV-1 from trigeminal ganglia. Occur in ~1/3 of primary herpetic gingivostomatitis.
57
***What are clinical syndromes for Herpes keratitis?
Reactivation of HSV-1, but virus travels down opthalmic branch rather than mandibular branch of trigeminal nerve ganglion ***limited to one eye
58
What is the leading cause of blindness due to disease in the US?
Herpes keratitis
59
What is a clinical syndrome of Herpetic whitlow?
Painful HSV-1 and HSV-2 infection usually of the finger
60
Genital herpes usually occurs on what specific part of the body?
(90% HSV-2, 10% HSV-1)
Male: Shaft of penis
Female: vulva, vagina, cervix, perianal area or inner thigh
61
What are clinical syndromes of Herpes encephalitis?
(HSV-1) Significant morbidity and mortality. Leading cause of sporadic encephalitis in US adults, w early onset of seizures. Temporal lobe involvement.
62
By which methods can herpes encephalitis be diagnosed in the lab?
Viral culture & isolation: from vesicles not crusted lesions (long wait)
PCR: for HSV DNA (accurate and fast)
Tzanck Smear: for epidermal multi-nucleated cells and eosinophilic intranuclear inclusions
63
What are two drugs used to treat and prevent Herpes virus?
Acyclovir: Topical cream or tablets for non-ocular herpes infections
Trifluidine: ophthalmic solution for HSV ocular infections.
64
What type of foods has been suggested in keeping herpesvirus outbreaks at a minimum?
High arginine, low lysine content food by suppressing HSV viral replication.
65
Where is the initial site of Varicella Zoster Virus?
Respiratory tract: viral aerosols inhaled and infects epithelial cells and fibroblasts.
66
How does VZV spread?
Forms synctia and spreads cell to cell. Viremia spreads virus from respiratory tract to lymphatics to liver and spleen.
67
What causes chicken pox?
Secondary viremia spreads virus to skin and mucous membranes, to cause rash. ***Reactivation causes vesicular rash, herpes zoster/shingles
68
What is the epidemiology of VZV?
ONLY HHV that spreads via airborne transmission: respiratory droplets and direct contact.
69
What are the clinical syndromes of vericella?
Chickenpox: vesiculopustular rash, "dewdrop on rose petal" starts on trunk and spreads to head and limbs. Painless but itchy. Can appear on mucous membranes.
70
What are clinical syndromes of Herpes zoster?
Shingles: reactivated VZV. More common with immunocompromised and older ppl. Severe neuronal pain prior to herpetic dermatome. Lesions. Orally, devitalization of teeth or root resorption.
71
What are the clinical syndromes of Postherpetic neuralgia?
Complication of shingles, affects nerve fibers and skin. Limited to area of skin of 1st shingle outbreak. Symptoms: pain sensitivity to touch & temp, itching, and numbness. Occurs in 1/2 of Zoster patients after 60 yo
72
What are clinical syndromes of Herpes zoster ophthalmicus?
Ranges from primary infection in lids to persistent conjunctivitis, keratouveitis, glaucoma, papillitis, ocular nerve palsy and deep ocular pain.
73
What are ways in VZV can be diagnosed in the lab? (Lab seldom required, clear-cut clinical signs)
Observation: "dewdrops on a rose petal" rash in stages of vesicles-->pustules-->scabs
Vesicle scraping histologically show Giant cells
VZV-specific antigens id'ed with immunofluorescent techniques and ELISA to detect anti-VZV antibodies from patient serum
74
What are 2 vaccines for varicella (chicken pox)?
Varivax and MMRV (ProQuad) vaccines
75
What is a vaccine for Herpes zoster?
Zostavax
76
What is given to pregnant women when exposed to VZV and newborns?
Varicella-zoster immunoglobulin (VZIg)
77
What are 3 vaccines against VZV for adults and immunocompromised pts?
Acyclovir, valcyclovir, famcyclovir
78
What are two other names for Epstein-Barr Virus (EBV)?
Lymphocryptovirus and herpesvirus 4 (HHV4)
79
What is the pathogenesis of EBV?
Spread through saliva (kissing disease) and infects epithelial cells of the oropharynx causing pharyngitis.
80
What happens when EBV infects B cells?
Lytic infection can spread to B cells in lymphatic tissue or blood and stimulates growth, altering normal immune B cell functions. Can lead to lymphoma.
81
What is mononucleosis?
Occurs partly due to T cell proliferation in response to EBV's B cell outgrowth. The T cells are activated to destroy infected B cells--> swollen lymph glands, spleen, and liver.
82
True or False
| Infection with EBV may be asymptomatic and vary in severity. Infection is common.
True
83
Who is EBV different, symptomatically, for normal adults and immunocompromised individuals?
Normal: infectious mononucleosis
Immunocompromised: Develop neoplastic disease
84
What are 7 clinical syndromes of EBV?
1. Infectious mononucleosis
2. Hairy Oral Leukoplakia
3. African Burkitt's Lymphoma
4. Hodgkin's Lymphoma
5. Nasopharyngeal carcinoma
6. Epithelial keratitis
7. Stromal keratitis
85
What is infectious mononucleosis?
(Glandular fever)
Children: mild or asymptomatic
Adolescent/Adults: Fatigue, high fever, malaise, pharyngitis, lymphadenopathy, and hepatosplenomegaly
86
What are meningoencelphalitis and Guillain-Barre syndrome?
Complications associated with infectious mononucleosis.
87
What is Hairy Oral Leukoplakia?
Corrugated white lesions in mouth on lateral border of tongue. Mostly in immunocompromised patients.
88
What is African Burkitt's Lymphoma (endemic lymphoma)?
B cell cancer of the jaw and face. Endemic to children in malarial regions of Africa. Connection in EVB with AfBL with malaria is unclear.
89
What is Hodgkin's lymphoma?
Malignancy of lymph tissue found in the lymph nodes, spleen, liver and bone marrow.
90
What is Nasopharyngeal carcinoma?
Cancer in nasopharynx. Endemic to adults in Orient but rare in US.
91
What is stromal keratitis?
Ring opacities due to multifocal anterior stromal infiltrates
92
Infectious mononucleosis a presenting sign for which disease?
Follicular conjunctivitis
93
How is EBV diagnosed in lab?
1. Large, lobed B lymphocytes with atypical nuclei and neutropenia: early indications of EBV infection
2. Immunofluorescent microscopy using fluorescein-tagged antibodies against anti_EBV antibodies or ELISA with anti-EBV antibodies
94
What is the treatment for EBV?
None
