level: Level 2
Questions and Answers List
STI: GEN HERPES
level questions: Level 2
| Question | Answer |
|---|---|
| the overall sequence homology between HSV I and II is about 50% the tropism for each virus is? | HSV I has tropism for oral epithelium and HSVII has tropism for genital epithelium, although in some unique populations, HSV I is associated with genital infection than HSV II |
| the mediator for HSV infection | attachment via ubiquitous(surface glycoproteins) receptors to cell: sensory neurons, leading to establishment of latency. |
| the HSV family comprises of large, DNA containing enviloped viruses and have identical morphology which cannot be distinguised from each other on the EM. the viridae structure include? | 1) core: contains linear DNA 2)capsid: 162 capsomers that form icosadeltahedron 3) tegument: contains protiens including Virion Host Shutoff (VHS) 4)envelope: proteins and lipids 5) surface protein: glycosylated protein spikes: gB-gJ( no gF gK &gN) |
| distributed world wide, it is the most common cause of genital ulcers in the USA. how is HSV transmitted? | close contact via inoculation of virus into susceptible mucosal surfaces through small cracks in the skin: oropharynx, cervix, conjunctiva. |
| increased age after onset of sexual activity and numbers of partners are independent factors associated with increased seroprevelance of HSV II antibodies. what is the distribution in men vs women? | seropositivity to HSVII is more common in women 25% than in men 10%. HSV II genital infection in women can be an indication of sexual abuse. |
| the overall mortality rate associated with HSV infection is related to 3 situations? | 1) perinatal infection 2) encephalitis 3) infection in immunocompromised. |
| HSV II infection are clustered perinatally in children, althugh genital infection in children can be an indication of sexual abuse. HSV I infections in children are transmitted via? | via saliva. |
| HSV I and II are characerised by unique biological properties: | 1) Neurovirulence: invade and replicate in nervous tissue 2) Latency: latent infection in nerve ganglion prox to site of infection 3)Reactiviation: in area supplied by ganglia where latency was established. may be induced via: fever, trauma, emotional stress, sunlingh and menstruation. |
| in HSV neurovirulence, the site of oral and genital infection are most commonly? | oral :trigeminal ganglia genital: sacral nerve root ganglia (s2-s5) |
| the reactivation and replication of latent HSV occur in areas of the ganglia in which latency was established resulting in overt or covert recurrent infection and shedding of HSV. Reactivation can be induced by? | 1) fever 2) trauma 3) sunlight 4) menstruation 5) emotional stress |
| clinical HSV infections | 1) acute herpetic gingivostomatitis(subclinical genital herpes; can also ne caused by HSV I) and pharyngotonsilitis( recurrent mucocutaneous HSV infection) 2) herpes labilis 3) herpetic whitlow 4) herpes gladiatorum 5) eczema herpeticum 6) genital herpes( primary and recurrent) |
| differential diagnosis of HSV | 1)candidiasis 2) chancroid 3) herpes zoster 4) syphilis 5) Bechet syndrome 6) HFMD |
| primary genital herpes with incubation period of 3-7 days, can be caused by both HSV I and II which can be asymptomatic. more severe and complicated in women, primary genital herpes is characterised by? | severe and prolonged systemic and local symptoms: fever, head aches, malaise and myalgia( prominent in first3-4 days). local symptoms include : itching, pain, dysuria, vaginal and urethral discharge and tender lymphadenopathy. primary HSV I protects or lessen the severity of HSV II or genital HSV I infection. |
| clinical features in women | herpetic vesicles appear: external genitalia, labia major/minor, vaginal vestibule and introitus. vesicles may rupture and tender ulcers. cervix may be involved in 70-90% of cases |
| clinical features in men | herpetic vesicles : glans penis, prepuce, shaft and sometimes scrotum, thighs, buttocks. herpetic Urethritis occur in 30-40% of men. |
| in men and women, ulcerative lesions persists for 4-15 days until encrusting and reepitheliazation occur. median duration of viral shedding is about ? | 12 days. |
| recurrent HSV infections will occur in 80% of primary infections; when compared recurrence is higher in: | HSV II reoccurs more than HSV I and lasts for 6-10 days. |
| lab diagnosis | 1)tzank smear: multinucleated giant cells and epithelial cells with eosiniphilic intranuclear inclusion bodies distinguish herpesviruses 2)DFA rapid test 3)Molecular: pcr rapid for confirmatory test 4) cell line culture: |
| in genital herpes, diagnosis include | viral culture pcr serology tzank prep |
| treatment of genital HSV | 1) nucleoside(guanosine) analog: antiviral triphosphate activity leads to DNA chain termination 2)acyclovir, valcyclovir, peniclovir, famciclovir: phosyphyrilation of parent compound by viral TK and cellular enzymes |