GU infections Flashcards
Double stranded DNA (large), enveloped alphaherpesvirus. DNA is encapsidated, space between capsid and envelope is filled with viral and cellular proteins - termed tegument.
Herpes Simplex virus (HSV-1 and 2
Defense mech of female tract:
- Epithelial cells
- Provide a mechanical barrier
- Produce/secrete antimicrobial molecules
- Transport IgA
- Process and present antigen
- Communicate with underlying immune cells
- Normal microbial flora
- Lactobacillus lowers vaginal pH to 4.2-5.0
The Five P’s
- Partners
- Prevention of pregnancy •Protection from STI’s •Practices
- Past history of STI’s
Test for chlamydia and gonorrhea simultaneously
- Voided urine PCR probe
- First urine after no urination x 1 hour
Dx for trichomas
- Trichomonas
- Microscopic exam of discharge
Dx of ureaplasma
- Ureaplasma
- PCR or culture
Understand lytic replication phase of HSV
associated with active transcription of numerous virus genes, viral DNA replication, assembly and release of infectious virions. virus mostly replicates in the mucosal epithelium during primary infection or following reactivation.
Latent infection -
limited to neurons – trigeminal or sacral ganglion; virus is quiescent, very limited virus gene expression, no viral DNA replication, no production of virions; viral DNA is maintained as an episome (extra “chromosome”) in latently infected neurons
sheds infectious particles frequently (25% chance daily), transmission can effectively occur in the absence of genital lesions. Virus is not stable in the environment – transmission is most efficient upon direct mucosa-mucosa contact.
Untreated HSV-2 carrier
Genital herpes is most often due to____ (termed recurrent infection clinically) of HSV-2, but can also be HSV-1 in some cases.
reactivation
HSV: Transplacental transmission is rare, but fetus can pick up the virus during natural delivery,leading to
neonatal herpes – a serious disease with some mortality and significant long-term sequelae in survivors.
Dx of HSV
Clinical presentation (vesicles), detection of virus in the lesions (culture, IFA, PCR), detection of HSV-1 or HSV-2 specific antibodies (determines infection status independent of the presence of genital lesions).
Pt has painless lesios on vagina, she said she had a headache and fever a few days ago. Dx?
HSV
Tx for HSV
Famciclovir, nucleoside analogs that are processed by viral (but not host) DNA polymerase and lead to chain termination during viral DNA synthesis.
Why can’t we create a vaccine for HSV
Treatment inhibits virus replication, but does not affect viral latency – this is why current treatments cannot clear HSV. No vaccine is available.
Linear double stranded DNA (very large) fused at both ends. Virion is ovoid to brick shaped; complex structure of the virion includes lateral bodies, core, and several membranes.
Molluscum Contagiosum – poxvirus
How is Molluscum a unique DNA virs?
Unlike any other DNA virus, poxviruses replicate exclusively in the cytoplasm – virus encodes and carries all proteins necessary for replication.
Transmission of molluscum
** direct contact or via fomites** (towels, etc) and virus is reasonably stable in the environment. Humans are the only known reservoir. Virus is usually cleared (can take up to 12 months). Virus replicates in the dermis.
Nodular to wart-like skin lesions, begin as papules and become umbilicated with central caseous plug; occur in cluster of 5-20 nodules
Molluscum Contagiosum
How do we Dx molluscum contagiousum
Based on the presentation of lesions (that may not be associated with inflammatory response) and histologically (large eosinophilic cytoplasmic inclusions – molluscum bodies).
Tx of MOlluscum contigiosum
If clearance of virus is delayed, nodules can be removed by scraping, application of liquid nitrogen, or iodine treatment. More severe disease in immunocompromised patients – can be treated with ritonavir or cidofovir. No vaccine is available.
papovavirus family, small circular double stranded DNA, icosahedral capsid, not enveloped, more than 100 subtypes – about a third of subtypes infect genital tract.
HPV
Viral cycle of HPV
Virus replication in the skin (infection occurs at the basal layer of epithelium by direct inoculation of a damaged skin), active replication is mostly in the upper epithelium layers to escape immune system. Throughout replication, viral DNA is maintained as an episome in the nucleus.
Replication is local and produces a wart. Most anogenital warts are caused by_____ Infection is self-limiting in most cases, but can take many months to years to clear.
HPV 6 and 11.
In some cases integration of HPV event leads to cancer. Cancer is associated with certain strains of HPV
(high risk, 16, 18, 31, and 45).
Explain pathology of HPV causing cancer
Further, most pathogenic integration events disrupt the expression of viral E2 gene which is a _negative regulator of viral E6 and E7 o_ncogenes. Due to high prevalence of infection (> 20 million in U.S.), HPV-induced cervical cancer is the second leading cause of cancer deaths in women.
Dx of HPV
Diagnosis: Clinical presentation of the wart. Pap smear for cancer screening, typing of HPV by PCR.
How does Guardasil work?
Vaccine is available against high risk strains (Gardasil) – recombinant capsid proteins (L1) self-assemble into empty virion like-particles that elicit protective humoral response.
Pleomorphic gram negative rods (coccobacilli), bacteria in this family are frequently found associated with mucous membranes, facultative anaerobes.
Cause Chancroids
Haemophilus ducreyi
Painful ulcerated lesion with lymphadenopathy adn pleomorphic gram Neg rods
Haemophilus ducreyi