DNA Viruses

Herpesviridae

• dsDNA

• icosahedral capsid

• enveloped virus

What is common in all 8 herpes viruses?

• all produce latency

Herpes Simplex Virus

• HSV 1 and HSV 2

  • very genetically similar

• result in lifelong infections

• asymptomatic shedding 

How are HSV-1 and HSV-2 transmitted?

• direct contact with active vesicles or body fluid

Clinical Manifestations of Herpes Simplex Virus

• oral herpes

• genital herpes

• ocular herpes

• herpetic whitlow

• neonatal herpes

• HSV encephalitis 

Herpes labialis (cold sores) are most commonly caused by what? 

• HSV-1 

2/3 of genital herpes is caused by what?

• HSV-2

ocular herpes is most commonly caused by what? 

• HSV-1 

Herpetic Whitlow

• infection of the fingers

neonatal herpes

• vertical transmission 

• fetus before birth 

• caused by HIV-2

HSV encephalitis

• neonates and immunocompromised patients

• central nervous system infection 

How is HIV-1 and 2 diagnosed

• DFA

• NAAT

• Viral Isolation 

• Serology 

  • type specific IgG

How does acyclovir help treat HSV 1-2

• nucleoside analog 

• disrupts DNA replication for virus 

How is HSV 1 and 2 treated?

• antiviral drugs: acyclovir

• barrier methods 

• wearing gloves (healthcare workers) 

Varicella Zoster Virus (VZV)

• HHV-3

• smallest genome amongst herpes virus

How is VZV transmitted

• primarily by respiratory droplets 

  • highly infectious 

what are the two main clinical manifestations of VZV?

• chickenpox

• shingles

Chickenpox

• Varicella 

• primary infection 

• mild fever and rash with vesicles

• more severe in adults

Shingles

• herpes zoster

• secondary infection from reactivation 

• caused by aging, immunosuppression, stress

How is VZV diagnosed

• DFA

• NAAT

• serology: IgM or IgG

• viral isolating 

how is VZV (HHV-3) treated/prevented

• airborne isolation 

• alcyclovir/valacylovir 

• varicella zoster immune globulin 

• vaccines

  • varivax

  • shingrix

Cytomegalovirus (CMV)

• HIV-5

• causes enlargement of cells

• as you get older, you are at higher risk of getting it 

what cells does CMV (HHV-5) infect?

• endothelial/epithelial cells

• PMNs

• monocytes/macrophages

• lymphocytes

how is CMV transmitted

• direct contact with bodily secretions

• sexual transmission 

• parenteral

  • transplants

• congenital

  • in utero 

what groups are at high risk for CMV?

• neonates/infants

• daycare/childcare workers

• blood/organ transplant  recipients

• immunocompromised individuals 

Clinical manifestations of CMV

• congenital infections

• primary infections

• transfusion associated infections

• severe infections with people who have HIV?AIDS

Congenital infections- CMV

• primary infection of mother while pregnant

what is the most common congenital infection in the US?

• CMV

Primary Infection- CMV

• may present as a self limiting mild-infectous mononucleosis like illness

Primary Transfusion: CMV

• CMV negative recipient is transfused with CMV-infected donor 

Reactivated Infections: CMV

• when seropositive recipient is transfused with seronegative or seropositive donor

How is CMV diagnosed?

• serology

• NAAT

• Histopathology 

  • Owls Eye 

• viral isolation

How is CMV treated/prevented

• screening blood donors

• administering CMV immune globulin

• barrier method/hygiene

• antiviral drugs

Epstein-Barr Virus (EBV)

• HHV-4 

• infects B lymphocytes and epithelial cells

How is EBV (HHV-4) transmitted?

• contact with body fluids (mainly saliva)

• sexual contact 

• blood transfusion/organ transplantation 

What clinical manifestations are associated with EBV?

• infectous mononucleosis

• chronic infections

• cancers

Infectous Mononucleosis-EBV

• infection presents as “Mono”

• in adolescents/young adults 

what triad of symptoms is associated with infectous mononucleosis-EBV

• fever

• pharyngitis

• cervical lymphadenopathy 

What complications can arise from infectious mononucleosis?

• splenomegaly

• hepatomegaly with jaundice 

Chronic infections- EBV

• IM like symptoms persist for long time

• individuals cant clear infection 

  • NK cells, and T cells are impaired 

• pneumonia and encephalitis can occur

What cancers are associated with EBV (HHV-4)

• Burkitt lymphoma

• nasopharyngeal carcinoma

• hairy leukoplakia

• hodgkin lymphoma

Burkitt Lymphoma

• malignant neoplasm of B cells in the germinal center 

• increased d-myc expression

• located in jaw

Nasopharyngeal carcinoma

• not yet linked to an oncogene

• squamous cell carcinoma 

Hairy Leukoplakia 

• bengin 

• primarily in patients with HIV/AIDS

Hodgkin Lymphoma

• has reed-sternberg cells present in lymph nodes

  • derived from B lymphocytes

What cells are associated with hodgkin lymphoma? 

• reed-sternberg cells 

How is EBV diagnoses

• hematology results

  • lymphocytosis with reactive lymphocytes

• liver enzymes: ALT and AST

What serology testing is done for EBV?

• Paul Bunnell heterophile antibody screening test 

Paul Bunnel heterophile antibody screening test

• heterophile Abs against Ags on sheep,horse, and bovine RBC, not on guinea pig kidney cells 

When conducting an EBV antibody panel, what antigens are you looking for?

• Viral Capsid Antigen 

  • Anti-VCA IgM

  • Anti-VCA IgG

• EBV nuclear antigen 

  • EBNA IgG

How is EBV treated

• self limiting

• antivirals 

Human Herpesvirus 6 (HHV-6)

• two species A and B

• infects children early in life 

what does HHV-6B cause?

• roseola rash

Human Herpesvirus 7 (HHV-7)

• infects T cells and host cells

what symptom in HHV-7 is clinically identical to HHV-6

• roseola rash 

Human Herpesvirus 8 (HHV-8)

• causes kaposi sarcoma 

  • oncogenic tumor of endothelial cells 

  • highly vascular tumors 

Adenoviridae (Adenovirus) 

• first isolated from adenoid tissue

• dsDNA genome

• naked icosahedral capsid 

How is adenovirus transmitted

• respiratory droplets,ocular secretion, stool 

• 50% of infections are asymptomatic 

What are different clinical manifestations of adenovirus?

• respiratory

• conjunctivitis 

• gastroenteritis

• severe infections in immunocompromised patients

Conjunctivitis “Pink Eye”

• epidemic keratoconjunctivitis 

• species B and D

• seen in adenovirus 

How is adenovirus diagnosed

• DFA

• Antigen detection 

• NAAT

• rapid shell vial culture serology 

How is adenovirus treated/prevented?

• handwashing

• NO VACCINE

• treat symptoms/provide care 

Papillomaviridae

• human papillomaviruses (HPVs)

• small, non-enveloped dsDNA viruses

• cause warts 

How is human papillomavirus transmitted?

• shedding from warts

• sexual intercourse

• indirect contact from communal showers/locker rooms

What is the most common sexually transmitted infection in the US?

• HPV

What are the two categories of HPV

• mucosal→ genital 

• cutaneous→ warts 

What does HPV infect

• basal keratinocytes of epithelium

What is produced from HPV?

• Koilocytes

What shows up in an HPV infection during a pap smear?

• koilocytes

Cutaneous Infection-HPV

• common, plantar, flat, and periungual warts 

• resolve in months to years

• NOT associated with cancer

Condyloma acuminatum

• wart in genital or anal area

• may cause itching,redness, pain 

• associated with HPV

What is linked to 90% of cervical carcinomas?

• HPV

What HPV types are high risk for cervical cancer?

• 16, 18, 31,45

What HPV types are low risk for cervical cancer?

• 6 and 11 

How is HPV diagnosed

• clinical evaluation 

• pap smears

  • koilocytes

• histopathology biopsy 

• NAAT

• staging 

How is HPV treated

• minimize exposure in communal areas

• barrier methods

• cervical cancer screening 

• wart removal

• Vaccines 

Vaccines for HPV mainly protect against what main groups of HPV?

• 16 and 18 

Poxviridae

• cause fluid filled vesicles to form on the skin

• largest viruses

• dsDNA genome 

Smallpox agent 

• variola virus

Smallpox

• exclusive to humans 

• highly infectious 

• single stereotype 

  • good for immunization 

how is smallpox transmitted?

• respiratory droplets 

• contact with vesicle 

• contact with contaminated items

What should happen if small pox is detected? 

• contact CDC 

  • this disease hasnt been seen in 40 years 

How is smallpox treated

• vaccinia virus

  • most closely resembles horsepox virus

  • still used today

ACAM200

• live vaccinia virus

JYNNEOS

• live-attenuated vaccinia virus

Mpox (Monkeypox)

• has a pus tubular febrile illness similar to smallpox

Molluscum Contagiosum

• only found in humans 

• transmission 

  • direct contact 

  • sexually 

  • formites

What is associated with Molluscum Contagiosum 

• mollusca wart like lesions

Parvoviridae

• naked ssDNA virus 

• human pathogen: Parvovirus B19 

How is parvoviridae transmitted

• respiratory droplets

• blood/blood products

• vertical transmission

what condition is associated with parvoviridae

• erythema infectiosum (fifth disease) 

Erythema Infectiosum (fith disease)

• has prodromal symptoms 

• also hs classic slapped cheek rash

What complications can occur in parvovirus B19 infections

• Transient aplastic crisis 

• Hydrops fetalis 

Why do complications occur in parvovirus B19

• infects and replicates in erythroid progenitor cells in bone marrow

Transient aplastic crisis (TAC)

• acute transient erythropoietic arrest 

• abrupt onset of severe or chronic anemia 

Hydrops fetalis

• severe fetal anemia

• could cause miscarriage or stillbirth

how is paroviridae diagnosed

• signs/symptoms

• serology 

• immunohistochemistry 

• NAAT