Herpes And Pox Viruses Flashcards
Give a brief description of the herpesviridae family
Enveloped dsDNA viruses
MW: 80-150,000kD
Latent infection after initial entry
Reactivation to produce recurrent infections
Some are associated with cancer
Eg EBV with nasopharyngeal carcinoma and Burkitt’s lymphoma
Human Herpes virus 8 with Kaposi sarcoma
Classify herpes viruses
HHV1- Herpes Simplex virus type 1
HHV2- Herpes Simplex virus type 2
HHV3- Varicella Zoster virus
HHV4- Epstein-Barr virus
HHV5- Human cytomegalovirus
HHV6- Human Herpes virus 6
HHV7- Human Herpes virus 7
HHV8- Kaposi sarcoma associated herpes virus
HHV1, 2, 3 (VSV) have their site of latency in the sensory nerve ganglia
True or false
True
HSV1- Trigeminal ganglion
HSV2- Sacral ganglion
HHV4 (EBV) has its site of latency where❓
B-lymphocytes
HHV5 (CMV) has its site of latency where❓
Epithelial cells
Leukocytes
Which HHVs have their site of latency in T lymphocytes❓
HHV6
HHV7
HHV8 (KSHV) has its site of latency in❓
B lymphocytes
Epithelial cells
In most developing countries, 90% of population have HSV1 antibody by the age of 30
True
The detection of HSV-2 antibody before puberty is a usual occurrence
True or false
False, it’s unusual
What is the prevalence of HSV-2 antibody in Africa❓
51-68%
More common in women
How is HSV-1 transmitted❓
How is HSV-2 transmitted❓
1.
Kissing
Direct contact with infected saliva
Respiratory droplets
- Sexual transmission
Is the primary infection of HHV is usually asymptomatic or symptomatic❓
Is the reactivation of HHV symptomatic or asymptomatic❓
Asymptotic or mild; painful blistering rash 1-3days post exposure
Asymptomatic; symptoms are less severe
Is viraemia more common in HSV-2 or HSV-1
HSV-2, usually occurs in immunocompromised patients
What are the stimuli for the reactivation of HHV❓
Fever
Stress
Sunlight
Immunosuppression
Oropharyngeal Herpes is characterized by❓
It is usually seen in what age group❓
How long does it last❓
It is usually seen in what category of HHV❓
1.
Fever blisters/Cold sores
Gingivostomatitis: ulcerative lesions involving the buccal mucosa, tongue, gums, pharynx
- Children <5 years
- Lasts 5-12 days
4.
HSV-1
Genital herpes, a very common sexually transmitted infection, is caused by❓
The efficiency of sexual transmission is greater from which sex❓
1.
HSV-1
HSV-2
2.
Men➡️Women
- In the primary infection of HSV-1 and HSV-2, what’s the incubation period of the virus❓
- How long does the primary infection last❓
- How would you identify it❓
- What course does it follow❓
- Is the primary infection more severe than the recurrent or vise versa❓
- Is a symptomatic viral shedding greater in HSV1/HSV2 ❓
5days
11-12days
- Multiple painful vesicopustular lesions, bilateral and extensive
- Bilateral enlarged tender inguinal lymph nodes
4. Papules ⬇️ Vesicles ⬇️ Pustules ⬇️ Ulcers ⬇️ Crusts ⬇️ Healed
- The primary infection is more severe; recurrent is mild and of short duration
- HSV2
A recurrent symptomatic infection with genital herpes is usually mild and short in duration
True or false
True
Is asymptomatic viral shedding greater in HSV-1/HSV-2❓
HSV-2
What is the mortality of Neonatal Herpes❓
What is usually the sequelae in those who survive❓
60%
Neurologic
Is viral encephalitis usually seen in HSV1/HSV2❓
Is meningitis usually seen in HSV1/HSV2❓
HSV-1, may also present with ocular infections (keratoconjunctivitis)
Meningitis is usually seen in HSV-2
- a. In using Tzanck test to diagnose HSV, what would you watch out for❓
b. Is this test sensitive and specific❓
2.
a. If the type specific serological test is positive for HSV2, what would that denote❓
b. Does the type specific serological test positive for HSV1 distinguish between an anogenital and orolabial infection❓
1.
a. Intranuclear inclusions/multinucleated giant cells
b. This test is insensitive and nonspecific for HSV
2.
a. An anogenital infection
b. A +ve HSV1 can’t distinguish btwn an anogenital and orolabial infection
How would you diagnose a case of HSV-1 / HSV-2❓
Viral culture
PCR
Antigen detection
Type specific serological test
Tzanck
How would you treat a case of HSV-1 / HSV-2❓
Would it eradicate the latent virus❓
- Acyclovir 400mg orally 7-10days
Valacyclovir 1g orally 7-10days
Famciclovir
Episodic and suppressive treatments ⬇️fq of recurrence by 70-80% in px w recurrence >6 per year
- No, it wouldn’t eradicate the latent virus
Varicella zoster virus VZV…
- Is transmitted by❓
- Is a highly contagious childhood disease, T/F❓
- Has an incubation period of❓
- Is presented clinically as❓
- Describe the disease progression
- Respiratory droplets
- T, it’s a highly contagious childhood dx
- Incubation period: 11-21 days
- Generalized vesiculopapular rashes
5. Macules ⬇️ Papules ⬇️ Vesicles ⬇️ Pustules ⬇️ Crust
Herpes zoster (Shingles)…
- Occurs by reactivation of❓
- Is most common in the elderly, T/F❓
- Is presented clinically as❓
- What is it’s complication❓
1. Reactivation of latent VZV ⬇️ multiplication with a sensory ganglion ⬇️ Travels down the sensory nerve to the skin
- T, most common in the elderly
- Vesicular lesions on the skin
- Post herpetic neuralgia
- What methods can be used to prevent and control VZV❓
- How would you diagnose a case of VZV❓
- What treatment will you give❓
- Use of Varicella Immune Globulin
Use of attenuated varicella/shingle vaccine
Isolation - Viral culture
Antigen detection (immunoflourescence antibody staining)
PCR - Acyclovir for >18yrs
children w severe dx
CMV…
- Is transmitted via what routes❓
- Causes which infections❓
1. Intra-uterine Perinatal Blood transfusion Organ transplantation
- Pneumonia
Ocular infections
What do you know about CMV❓
- Most individuals are infected with in the first few years of life
- Rarely causes disease in healthy pple
- It is an infectious mononucleosis-like syndrome, with subclinical infections
- Establishes lifelong latent infections
- Viral shedding through pharynx and urine, months to years after primary infection
What diseases can occur in a CMV infected immunocompromised pt❓
Intestinal pneumonia (most common)
Retinitis
Enteritis
Disseminated infection
How would you diagnose a case of CMV❓
What treatment will you give❓
How can you control it❓
- PCR
Isolation of virus (human fibroblasts)
Antigen detection; pp65 assay (immunoflourescence)
Antibody detection (IgG past infection, IgM new infection)
- Ganciclovir
- Isolation of newborn
Screening of transplant donors and recipients for CMV antibody
What do you know about EBV❓
Most pple are infected by adulthood
Causes immortalization of infected cell lines
Viral shedding occurs through saliva
EBV/Infectious mononucleosis/Glandular Fever…
- Is transmitted via❓
- Initiates infection in the❓
- Is replicated in the❓
- Is reactivated by❓
- Has an incubation period of❓
- Presents clinically as❓
- Last for how long❓
- Close contact/Kissing
- Oropharynx
- Epithelial cells/surface B lymphocytes of pharynx and salivary gland
- Immunosuppression
4-7 weeks
6. Fever/Malaise Lymphadenopathy Sore throat Hepatosplenomegaly
2-4 weeks
Which cancers can be caused by EBV❓
Nasopharyngeal ca
Burkitt’s lymphoma
Hodgkin’s disease
Non-Hodgkin’s lymphoma
Gastric ca
Oral hairy leukoplakia (esp on AIDS)
Lymphoproliferative disorders
What tests will you order for if you suspect a case of EBV❓
PCR
Isolation of virus
Antibody detection (IgG/IgM/EBNA)
Heterophile antibody test/monospot
List:
- Latent Phase antigens
- Late phase antigens
for EBV
- Latent Phase:
EBNA (EBV nuclear antigens)
LMP (late membrane proteins) - Late Phase:
VCA (Viral capsid antigens)
Viral glycoproteins
70-80% of pt with acute IM develop heterophil antibodies that agglutinate sheep RBCs
True or false
True
Roseola/exanthem subitum
- Is caused by which HHV❓
- Is characterized by❓
- Reactivated by❓
- HHV6
- Fever (3days)
Maculopapular rash from trunk➡️extremities - Immunosuppression
Give a brief description of the pox viruses
- Large, complex structure
- Brick-shaped/ovoid
- dsDNA-carrying virions
- 200 * 300nm
- Envelope is not acquired by budding and not essential for infectivity
- Replication occurs in the cytoplasm
Small pox (orthopoxvirus)….
- Was eradicated in❓
- Presents clinically as❓
- Is a potential bioterrorist weapon, T/F❓
1979
Uniform papulovesicular rash that evolves to pustules over 1-2weeks
True
Molluscum contagiosum (molluscipoxvirus)…
- Is transmitted via❓
- Has an incubation period of❓
- An infection presents clinically as❓
- Can be treated by❓
Direct skin to skin contact
2-8 weeks
2 to 10mm, benign, painless, nodular, pale, firm lesions in the epidermis
Curettage/careful removal of the central core w forceps
Orf/Parapoxvirus of goat and sheep…
- Is acquired by❓
- Has a duration of infection of❓
- Presents clinically as❓
- Can be diagnosed using❓
- Close contact with infected animal
Inoculation through cuts/abrasions - About 35 days
- Begins as a vesicle
Evolved into nodular mass
Develops central necrosis
4. Clinical appearance Occupational history Serology Electron microscopy
- Describe the epidemiology of monkeypox
- It’s similar to smallpox but milder, T/F❓
- Is transmitted by❓
- Has an incubation period of❓
- Clinical presentation❓
- Prodrome lasts for how long❓
- How would you treat Monkeypox❓
1.
Rare
Occurs in Central and West Africa
- True
- Contact w cutaneous/mucosal lesions of infected animals
Contact with blood/body fluids of infected humans
5-21 days
5. Fever/malaise Headache Lymphadenopathy Enanthem on tongue and mouth
1-5days
- Isolation
No specific treatment available
Vaccine against smallpox (85% effective)
A seeming presentation w monkeypox could also be❓
Smallpox Chickenpox Measles Bacterial skin infections Scabies Secondary syphilis Drug related allergies
Would tests would you request for to diagnose monkeypox❓
Clinical presentation ELISA Antigen detection tests PCR Virus isolation
