Transcript Herpesviruses

HERPES SIMPLEX VIRUS
Dr. Hani Masaadeh
MD, Ph.D
HERPES SIMPLEX VIRUS (HSV)
• HSV-1 and HSV-2 infect more than one-third
of the world’s population
• HSV-2 is responsible for the majority of cases
of genital herpes, although HSV-1 can also
lead to genital infections
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HERPES SIMPLEX VIRUS (HSV)
• Triggers for viral reactivation include:
– Immunodeficiency
– Fever
– Ultraviolet light
– Stress ????
– Trauma
– Menstruation
– Sexual Intercourse
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HERPES SIMPLEX VIRUS (HSV)
MANIFESTATIONS
• Initial episodes are
more severe than
recurrences
• After an incubation period of several days
patients notice a prodrome:
– Itching
– Burning
– Erythema
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HERPES SIMPLEX VIRUS (HSV)
MANIFESTATIONS
• Classic vesicles which are painful appear on
the:
– Cervix
– Vagina
– Vulva
– Rectum
– Perineum
– Surrounding skin
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HERPES
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HERPES
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HERPES SIMPLEX VIRUS (HSV)
DIAGNOSIS
• Clinical diagnosis is made
by recognition of multiple,
shallow and tender ulcerations or vesicles on or
around the genitalia
• Laboratory diagnosis
– Viral isolation by tissue culture
• Gold standard
• Can take up to 5 days
• Sensitivity is only 70% - 80%
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HERPES SIMPLEX VIRUS (HSV)
DIAGNOSIS
– Antigen Detection and Tzanck Tests
• Lower sensitivity
– Serologic studies
• Not helpful during the primary illness because of
the delay in antibody production
– PCR testing
• Sensitive (96%) and specific (99%)
• High cost
• Limited availability
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HERPES SIMPLEX VIRUS (HSV)
TREATMENT - ACYCLOVIR
• Acyclovir binds viral DNA polymerase and
ends replication
• Medications must be administered early in
the course of the illness because HSV
replication may end as soon as 48 hours
into a recurrence
• Only to be used in pregnancy if there is a
severe infection
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Cytomegalovirus
Properties
• Belong to the betaherpesvirus subfamily of herpesviruses
• double stranded DNA enveloped virus
• Nucleocapsid 105nm in diameter, 162 capsomers
• The structure of the genome of CMV is similar to other
herpesviruses, consisting of long and short segments
which may be orientated in either direction, giving a total
of 4 isomers.
• A large no. of proteins are encoded for, the precise
number is unknown.
Epidemiology
• CMV is one of the most successful human pathogens, it can
be transmitted vertically or horizontally usually with little
effect on the host.
• Transmission may occur in utero, perinatally or postnatally.
Once infected, the person carries the virus for life which may
be activated from time to time, during which infectious
virions appear in the urine and the saliva.
• Reactivation can also lead to vertical transmission. It is also
possible for people who have experienced primary infection
to be reinfected with another or the same strain of CMV, this
reinfection does not differ clinically from reactivation.
Clinical Manifestations
• Congenital infection - may result in cytomegalic inclusion
disease
• Perinatal infection - usually asymptomatic
• Postnatal infection - usually asymptomatic. However, in a
minority of cases, the syndrome of infectious
mononucleosis may develop which consists of fever,
lymphadenopathy, and splenomegaly. The heterophil
antibody test is negative although atypical lymphocytes
may be found in the blood.
• Immunocompromised patients such as transplant recipients
and AIDS patients are prone to severe CMV disease such
as pneumonitis, retinitis, colitis, and encephalopathy.
• Reactivation or reinfection with CMV is usually
asymptomatic except in immunocompromised patients.
Congenital Infection
• Defined as the isolation of CMV from the saliva or urine within 3
weeks of birth.
• Commonest congenital viral infection, affects 0.3 - 1% of all live
births. The second most common cause of mental handicap after
Down's syndrome and is responsible for more cases of congenital
damage than rubella.
• Transmission to the fetus may occur following primary or recurrent
CMV infection. 40% chance of transmission to the fetus following a
primary infection.
• May be transmitted to the fetus during all stages of pregnancy.
• No evidence of teratogenecity, damage to the fetus results from
destruction of target cells once they are formed.
Laboratory Diagnosis (1)
• Direct detection
– biopsy specimens may be examined histologically for CMV
inclusion antibodies or for the presence of CMV antigens.
However, the sensitivity may be low.
– The pp65 CMV antigenaemia test is now routinely used for
the
rapid
diagnosis
of
CMV
infection
in
immunocompromised patients.
– PCR for CMV-DNA is used in some centers but there may
be problems with interpretation.
Laboratory Diagnosis (2)
• Virus Isolation
– conventional cell culture is regarded as gold standard but
requires up to 4 weeks for result.
– More useful are rapid culture methods such as the DEAFF
test which can provide a result in 24-48 hours.
• Serology
– the presence of CMV IgG antibody indicates past infection.
– The detection of IgM is indicative of primary infection
although it may also be found in immunocompromised
patients with reactivation.
Cytopathic Effect of CMV
(Courtesy of Linda Stannard, University of Cape Town, S.A.)
Specimens for Laboratory Diagnosis
Site for virus culture
Urine Saliva Blood Tissue affected
Serology
IgG IgM
Neonates
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Adults
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Pregnant women
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Immunocompromised
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Treatment
• Congenital infections - it is not usually possible to detect
congenital infection unless the mother has symptoms of primary
infection. If so, then the mother should be told of the chances of
her baby having cytomegalic inclusion disease and perhaps
offered the choice of an abortion.
• Perinatal and postnatal infection - it is usually not necessary to
treat such patients.
• Immunocompromised patients - it is necessary to make a
diagnosis of CMV infection early and give prompt antiviral
therapy. Anti-CMV agents in current use are ganciclovir,
forscarnet, and cidofovir.
Human Papillomavirus (HPV)
Genital Warts
Human Papillomavirus
(commonly called Genital Warts)
• Human Papillomavirus (HPV) is a virus that can
cause various disease states including “genital” or
“venereal” warts
• Papillomaviruses are a complex group of DNA
tumor viruses. They can cause benign growths
(papillomas), cancers, or more commonly,
transient infections
• HPV infection is causally associated with cervical
cancer ; other genital cancers including anal,
penile, vulvar, and vaginal cancers may have HPV
as co-factor
HPV Prevalence
• Most common STD
• An estimated sexually active adolescents and
young adults 15-24 years of age are infected with
genital HPV
• An estimated people infected with genital HPV are
infected with multiple types of the virus
Risk Factors for Acquiring a
Genital HPV Infection
• Young age (less than 25 years)
• Multiple sex partners
• Early age at first intercourse (16 years or
younger)
• Male partner has (or has had) multiple sex
partners
HPV Transmission
• Direct skin-to-skin contact
– Usually, but not always sexual contact
• Infected birth canal
• Fomites (very rare)
HPV Incubation
• Average incubation is 3 weeks to 1 year
• Possibly years before appearance of warts or
cervical abnormalities
• Some will be transient and may never be
detected
Common Symptoms of Genital Warts in
Males & Females
• The symptoms may include single or multiple
fleshy growths around the penis, scrotum, groin,
vulva, vagina, anus, and/or urethra
• They may also include: itching, bleeding, or
burning, and pain
• The symptoms may recur from time to time
Perianal Warts
Source: Cincinnati STD/HIV Prevention Training Center
Complications of Genital Warts
(if untreated)
• It may destroy body tissue around the
genitals and anus
• For pregnant women
– Delivery complications or need for C-section
Testing & Treatment for
Genital Warts
• Can be detected in a
clinical exam;
• Can be treated by
removing the warts;
• The virus cannot be
removed, so the warts
may grow back.
HPV Diagnostic Techniques
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History
Visual exam
Pap smears
DNA testing
HPV Treatment Options
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Chemical agents
Cryotherapy
Electrosurgery
Surgical excision
Laser surgery
Imiquimod (Aldara)
Defer treatment
Natural therapies
Perinatal complications
Can a person be
re-infected with HPV?
• There appears to be humoral and probably cellular
immunity that develops to a specific type of HPV
after a person has been infected with it and “has
cleared” it.
• The risk for re-infection with that specific type of
HPV appears to be rare.
• However, a person can be infected with more than
one type of HPV
Molluscum contagiosum
• Molluscum contagiosum is a common, selflimiting, nonscarring, papular, viral skin
infection
• Groups of papules are found anywhere except
palms of hands or soles of feet, containing
infectious, white, curd-like material
• Found mainly in children and young, sexually
active adults
• Transmission by close contact, for
Transmission by close contact, for
example, sport, occupational, sexual
Adult disease is associated with sexually
transmitted infections and may be a
marker for late-stage HIV infection
Treatment is often unnecessary in children
but may prevent further sexual
transmission in adults
Transmission by close contact, for
example, sport, occupational, sexual
Adult disease is associated with sexually
transmitted infections and may be a
marker for late-stage HIV infection
Treatment is often unnecessary in children
but may prevent further sexual
transmission in adults