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Microbio:DNA Virus
USMLE Step 1
Virus | Pathology |
---|---|
Parvovirus B19 (naked Parvoviridae) | causes erythema infectiosum aka 5th disease or slapped cheek disease, bright red cheeks bilaterally,reticular rash of arms,also causes aplastic anemia in those w/ bone marrow path & spontaneous abortion,naked DNA virus,hydrops fetalis (fluid accumulation) |
JC virus (naked Papovaviridae) | cause leukoencephalopathy aka progressive multifocal leukoencephalopathy, demyelinates CNS by infect & kill oligodendrocytes, seen more often in HIV |
Human papillomovirus causing papillomas (naked Papovaviridae) | infects squamous epithelial cause peri-nuclear clearing termed koilocytes,benign tumors,E6 & E7 inactivate p53 & RB genes causing uncontrolled growth,contracted by skin 2 skin or genital contact,1-4 plantar & skin,6-11 genital warts, high risk 16 & 18 |
Human papillomovirus causing carcinoma of cervix, penis & anus (naked Papovaviridae) | assoc w/ many cervical, penile & anal carcinomas, esp 16, 18 & those in the 30s/40s/50s cause premalignant lesions, these bind to p53 & RB gene protein more tightly than the other HPV types, vaccinate w/ Gardasil ages 9-26 vs. types 6, 11, 16 & 18 |
Adenovirus (naked Adenoviridae) | infects upper respiratory tract,sxs fever,exudative pharyngitis,sore throat,coryza (head cold),conjunctivitis,bronchitis or pneumonia,transmitted by aerosol,fecal-PO,prevented w/ vaccine,child promote excessive Peyer patch enlrg = risk 4 intussusception |
Smallpox (enveloped w/ complex capsid from poxviridae) | bio-warfare agent, humans only reservoir, transmission route from respiratory to lymph to bld to organs to bld again then to skin causing sxs of fever, malaise, rash on face spreading to trunk then extremities, vaccine confers immunity up to 10 yrs |
Molluscum contagiosum (enveloped w/ complex capsid from poxviridae) | features small,pink,papules w/ indented crater in the ctr filled w/ a white core called "umbilicated papules", transmitted via sexual contact & children via touching each other-if child has it consider possibility of child abuse,tx w/ curettage or liq N2 |
Hepatitis B (enveloped hepadnaviridae), note interferon alpha is tx | asx usually,RUQ pain,fever,jaundice & malaise,transmitted via bld,sex or vertically e.g. breastfeeding,> 75% cases in Asia,+HBsAg in those w/ infection & > 6 mons are chronic that can cause hepatocellular carcinoma,vaccine use +anti-HBsAg determine status |
Herpes Simplex 1 (enveloped herpesviridae), note tx is acyclovir | more assoc w/ infections above waist in mouth around trigeminal ganglion during latency,transmission via direct contact w/ lesion or saliva,sex or vertically during birth,80% of pop infected,dx Tzanck smear w/ viral culture & ELISA,vesicles are infectious |
Herpes Simplex 2 (enveloped herpesviridae), note acyclovir is tx | assoc w/ infections below waist-genital that rests in lumbar & sacral dorsal root ganglia during latency,transmit w/ direct contact,saliva,sex or vertically during birth,dx screen w/ Tzanck smear-confirm w/ virus culture & ELISA,painful vesicle infectious |
Varicella-Zoster chickenpox (enveloped herpesviridae) | DRG site of latency,infects upper respiratory mucosa from bld to skin cause vesicular rash on trunk then spreads to crust over=pruritic,dx w/ Tzanck smear,confirm w/ anti-serum test or serum titers of VZV IgM,tx w/ acyclovir |
Epstein-Barr (enveloped herpesviridae) | transmit by saliva or respiratory secretions, prod heterophile antibodies & atypical lymphocytes (CD8s), during latency w/in B lymphocyte, assoc w/ infectious mono, Burkitt's lymphoma, nasopharyngeal CA, thymic CA & different types of B-cell lymphoma |
Cytomegalovirus (enveloped herpesviridae), note can also tx w/ foscarnet | transmit via body fluids like congenital,urine,saliva-#1,sexual,transplant & bld,doesnt prod heterophile Abs,asx except in fetus & immunocompromised,site of latency in leukocytes,kidney & cervix,dx w/ Ab & owl eye intranuclear inclusions,DOC ganciclovir |
Human Herpes Virus 6 (enveloped herpesviridae) | roseola (exanthem subitum; 6th disease), abrupt onset fever, lasts 1-5 days, pink rash on trunk occurs only after fever ends, transmission respiratory rt |
Human Herpes Virus 8 (enveloped herpesviridae), note tx by excision or radiation or interferon-alpha or vinblastine | Kaposi's sarcoma,most common cancer in AIDS pts-inactivates RB=uncontrolled cell growth=malignancy of vascular endothelium w/ extravasation of bld,dark purple,flat 2 nodular lesions on skin,in PO cavity,GI tract,soles & in lungs,transmit sexually,dx by bx |
Vaccinia (enveloped w/ complex capsid from poxviridae) | cowpox (milkmaid blisters). The original vaccine for smallpox, and the origin of the idea of vaccination, was cowpox, reported on by Edward Jenner in 1796. |
Varicella Zoster Shingles (enveloped herpesviridae) | DRG site of latency,re-activation of latent VZV erupt along sensory nerve along dermatome,dx w/ Tzanck smear,confirm w/ anti-serum test,tx w/ acyclovir although DOC is gabapentin, assoc w/ Reye syn (encephalopathy w/ liver degeneration) more likely w/ ASA |