Term
| Properties of Herpesviruses |
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Definition
• Enveloped, double-stranded DNA viruses
• Genome consists of long and short fragments which may be orientated in either direction, giving a total of four isomers
• Three subfamilies
– Alpha herpesviruses: HSV-1, HSV-2, VZV – Beta herpesviruses: CMV, HHV-6, HHV-7 – Gamma herpesviruses: EBV, HHV-8
• Set up latent or persistent infection following primary infection
• Reactivation is more likely to take place during periods of immunosuppression
• Both primary infection and reactivation are likely to be more serious in immunocompromised patients |
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Term
| Properties of herpes simplex viruses |
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Definition
• Belong to the alpha herpesvirus subfamily of herpesviruses
• Double-stranded DNA-enveloped virus with a genome of around 150 kb
• The genome of HSV-1 and HSV-2 share 50–70% homology
• They also share several cross-reactive epitopes with each other
– There is also antigenic cross-reaction with VZV
• Man is the only natural host for HSV |
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Term
| epidemiology of herpes simplex viruses |
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Definition
• HSV is spread by contact, as the virus is shed in saliva, tears, genital, and other secretions.
• By far the most common form of infection results from a kiss given to a child or adult from a person shedding the virus.
• Primary infection is usually trivial or subclinical in most individuals. It is a disease mainly of very young children.
• There are two peaks of incidence, the first at 0–5 years and the second in the late teens, when sexual activity commences.
• About 10% of the population acquires HSV infection through the genital route, and the risk is concentrated in young adulthood.
• Generally HSV-1 causes infection above the belt and HSV-2 below the belt. In fact, 40% of clinical isolates from genital sores are HSV-1, and 5% of strains isolated from the facial area are HSV-2.
– This data is complicated by oral sexual practices.
• Following primary infection, 45% of orally infected individuals and 60% of patients with genital herpes will experience recurrences.
• The actual frequency of recurrences varies widely between individuals. The mean number of episodes per year is about 1.6. |
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Term
| pathogenesis of herpes simplex viruses |
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Definition
• During the primary infection, HSV spreads locally and a short-lived viremia occurs, whereby the virus is disseminated in the body. Spread to the craniospinal ganglia occurs.
• The virus then establishes latency in the craniospinal ganglia.
• The exact mechanism of latency is not known; it may be true latency where there is no viral replication or viral persistence where there is a low level of viral replication.
• Reactivation
– It is well known that many triggers can provoke a recurrence. These include physical or psychological stress, infection (especially pneumococcal and meningococcal), fever, irradiation (including sunlight), and menstruation. |
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Term
| clinical manifestations of herpes simplex viruses |
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Definition
• HSV is involved in a variety of clinical manifestations which include:
– Acute gingivostomatitis
– Herpes labialis (cold sore)
– Ocular herpes
– Herpes genitalis
– Other forms of cutaneous herpes – Meningitis
– Encephalitis
– Neonatal herpes |
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Term
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Definition
• Acute gingivostomatitis
– Acute gingivostomatitis is the most common manifestation of primary herpetic infection.
– The patient experiences pain and bleeding of the gums.1–8mm ulcers with necrotic bases are present.
– Neck glands are commonly enlarged, accompanied by fever.
– Usually a self-limiting disease which lasts around 13 days.
• Herpes labialis (cold sore)
– Following primary infection, 45% of orally infected individuals will experience reactivation. The actual frequency of recurrences varies widely between individuals.
– Herpes labialis (coldsore) is a recurrence of oral HSV.
– A prodrome of tingling, warmth, or itching at the site usually heralds the recurrence. About 12 hours later, redness appears, followed by papules and then vesicles. |
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Term
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Definition
• HSV causes a broad spectrum of ocular disease, ranging from mild superficial lesions involving the external eye, to severe sight- threatening diseases of the
inner eye.
• Diseases caused include the following:
– Primary HSV keratitis: dendritic ulcers
– Recurrent HSV keratitis
– HSV conjunctivitis
– Iridocyclitis, chorioretinitis, and cataract |
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Term
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Definition
• Genital lesions may be primary, recurrent, or initial.
• Many sites can be involved which include the penis,
vagina, cervix, anus, vulva, bladder, sacral nerve
routes, the spinal and the meninges.
• The lesions of genital herpes are particularly prone to
secondary bacterial infection.
• Dysuria is a common complaint; in severe cases,
there may be urinary retention.
• Local sensory nerves may be involved leading to the
development of a radiculitis. A mild meningitis may be
present.
• 60% of patients with genital herpes will experience
recurrences.
– Recurrentlesionsintheperianalareatendtobe
more numerous and persists longer than their oral HSV-1 counterparts. |
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Term
| Herpes Simplex Encephalitis (HSE) |
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Definition
• Herpes simplex encephalitis is one of the most serious complications of herpes simplex disease. There are two forms:
– Neonatal: There is global involvement and the brain is almost liquefied. The mortality rate approaches 100%.
– Focal disease: The temporal lobe is most commonly affected. This form of the disease appears in children and adults. It is possible that many of these cases arise from reactivation of the virus. The mortality rate is high (70%) without treatment.
• It is of utmost importance to make a diagnosis of HSE early. It is general practice that IV acyclovir is given in all cases of suspected HSE before laboratory results are available. |
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Term
| Laboratory Diagnosis of herpes simplex |
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Definition
• Direct detection
– Electron microscopy of vesicle fluid—rapid result but cannot
distinguish between HSV and VZV.
– Immunofluorescence of skin scrapings—can distinguish between HSV and VZV.
– PCR—now used routinely for the diagnosis of herpes simple encephalitis.
• Virus isolation
– HSV-1 and HSV-2 are among the easiest viruses to cultivate. It
usually takes only 1–5 days for a result to be available.
• Serology
– Not that useful in the acute phase because it takes 1–2 weeks before antibodies appear after infection. Used to document to recent infection. |
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Term
| management of herpes simplex |
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Definition
• At present, there are only a few indications of antiviral chemotherapy, with the high cost of antiviral drugs being a main consideration. Generally, antiviral chemotherapy is indicated where the primary infection is especially severe, where there is dissemination, where sight is threatened, and herpes simplex encephalitis.
– Acyclovir: this the drug of choice for most situations at present. It is available in a number of formulations.
• IV (HSV infection in normal and immunocompromised patients)
• Oral (treatment and long-term suppression of mucocutaneous herpes and prophylaxis of HSV in immunocompromised patients)
• Cream (HSV infection of the skin and mucous membranes)
• Ophthalmic ointment
– Famciclovir and valacyclovir: oral only, more expensive than acyclovir.
– Other older agents: e.g., idoxuridine, trifluorothymidine, vidarabine (ara-A).
• These agents are highly toxic and are suitable for topical use for opthalmic infection only |
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Term
| Varicella—Zoster Virus properties |
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Definition
• Belong to the alphaherpesvirus subfamily of herpesviruses
• Double-stranded DNA enveloped virus
• Genome size 125 kbp, long and short fragments with a total of four isometric forms.
• One antigenic serotype only, although there is some cross reaction with HSV |
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Term
| Varicella—Zoster Virus epidemiology |
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Definition
• Primary varicella is an endemic disease. Varicella is one of the classic diseases of childhood, with the highest prevalence occurring in the 4- to 10-year-old age group.
• Varicella is highly communicable, with an attack rate of 90% in close contacts.
• Most people become infected before adulthood, but 10% of young adults remain susceptible.
• Herpes zoster, in contrast, occurs sporadically and evenly throughout the year. |
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Term
| Varicella—Zoster Virus pathogenesis |
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Definition
• The virus is thought to gain entry via the respiratory tract and spreads shortly after to the lymphoid system.
• After an incubation period of 14 days, the virus arrives at its main target organ, the skin.
• Following the primary infection, the virus remains latent in the cerebral or posterior root ganglia. In 10–20% of individuals, a single recurrent infection occurs after several decades.
• The virus reactivates in the ganglion and tracks down the sensory nerve to the area of the skin innervated by the nerve, producing a varicelliform rash in the distribution of a dermatome. |
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Term
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Definition
• Primary infection results in varicella (chickenpox).
• Incubation period of 14–21 days.
• Presents fever, lymphadenopathy, a widespread vesicular rash.
• The features are so characteristic that a diagnosis can usually be made on clinical grounds alone.
• Complications are rare but occur more frequently and with greater severity in adults and immunocompromised patients.
• Most common complication is secondary bacterial infection of the vesicles.
• Severe complications which may be life threatening include viral pneumonia, encephalitis, and hemorrhagic chickenpox. |
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Term
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Definition
• Herpes zoster mainly affects a single dermatome of the skin.
• It may occur at any age but the vast majority of patients are more than 50 years of age.
• The latent virus reactivates in a sensory ganglion and tracks down the sensory nerve to the appropriate segment.
• There is a characteristic eruption of vesicles in the dermatome which is often accompanied by intensive pain which may last for months (postherpetic neuralgia).
• Herpes zoster affecting the eye and face may pose great problems.
• As with varicella, herpes zoster is a far greater problem in immunocompromised patients in whom the reactivation occurs earlier in life and multiple attacks occur as well as complications.
• Complications are rare and include encephalitis and disseminated herpes zoster. |
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Term
|
Definition
• 90% of pregnant women already immune; therefore, primary infection is rare during pregnancy.
• Primary infection during pregnancy carries a greater risk of severe disease, in particular pneumonia.
• Neonatal
– VZV can cross the placenta in the late stages of pregnancy to
infect the fetus congenitally.
– Neonatal varicella may vary from a mild disease to a fatal
disseminated infection.
– If rash in mother occurs more than 1 week before delivery, then
sufficient immunity would have been transferred to the fetus.
– Zoster immunoglobulin should be given to susceptible pregnant
women who had contact with suspected cases of varicella.
– Zoster immunoglobulin should also be given to infants whose
mothers develop varicella during the last 7 days of pregnancy or the first 14 days after delivery. |
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Term
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Definition
The clinical presentations of varicella or zoster are so characteristic that laboratory confirmation is rarely required. Laboratory diagnosis is required only for atypical presentations, particularly in the immunocompromised.
• Virus isolation: rarely carried out as it requires 2–3 weeks for a results.
• Direct detection: electron microscopy may be used for vesicle fluids but cannot distinguish between HSV and VZV. Immunofluorescence on skin scrapings can distinguish between the two.
• Serology: the presence of VZV IgG is indicative of past infection and immunity. The presence of IgM is indicative of recent primary infection. |
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Term
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Definition
• Uncomplicated varicella is a self-limited disease and requires no specific treatment. However, acyclovir had been shown to accelerate the resolution of the disease and is prescribed by some doctors.
• Acyclovir should be given promptly to immunocompromised individuals with varicella infection and normal individuals with serious complications such as pneumonia and encephalitis.
• Herpes zoster in a healthy individual is not normally a cause for concern. The main problem is the management of the postherpetic neuralgia.
• The International Herpes Management Forum recommends that antiviral therapy should be offered routinely to all patients over 50 years of age presenting with herpes zoster.
• Three drugs can be used for the treatment of herpes zoster: acyclovir, valicyclovir, and famciclovir. There appears to be little difference in efficacy among them. |
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Term
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Definition
• Preventive measures should be considered for individuals at risk of contracting severe varicella infection, e.g., leukemic children, neonates, and pregnant women.
• Where urgent protection is needed, passive immunization should be given. Zoster immunoglobulin (ZIG) is the preparation of choice but it is very expensive. Where ZIG is not available, HNIG should be given instead.
• A live attenuated vaccine is available. There had been great reluctance to use it in the past, especially in immunocompromised individuals since the vaccine virus can become latent and reactivate later on.
• However, recent data suggests that the vaccine is safe, even in children with leukemia provided that they are in remission.
• It is highly debatable whether universal vaccination should be offered since chickenpox and shingles are normally mild diseases. |
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Term
| cytomegalovirus properties |
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Definition
• Belong to the betaherpesvirus subfamily of herpesviruses.
• Double-stranded DNA enveloped virus.
• Nucleocapsid 105 nm 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 four isomers.
• A large number of proteins are encoded for, the precise number is unknown. |
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Term
| epidemiology of cytomegalovirus |
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Definition
• 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.
• In developed countries with a high standard of hygiene, 40% of adolescents are infected and ultimately 70% of the population is infected. In developing countries, over 90% of people are ultimately infected. |
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Term
| pathogenesis of cytomegalovirus |
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Definition
• Once infected, the virus remains in the person for life and may be reactivated from time to time, especially in immunocompromised individuals.
• The virus may be transmitted in utero, perinatally, or postnatally. Perinatal transmission occurs.
• Perinatal infection is acquired mainly through infected genital secretions or breast milk. Overall, 2–10% of infants are infected by the age of 6 months worldwide. Perinatal infection is thought to be 10 times more common than congenital infection.
• Postnatal infection mainly occurs through saliva. Sexual transmission may occur as well as through blood and blood products and transplanted organs. |
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Term
| clinical manifestations of cytomegalovirus |
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Definition
• 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 heterophile 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. |
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Term
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Definition
• Defined as the isolation of CMV from the saliva or urine within 3 weeks of birth.
• Most common 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 teratogenicity; damage to the fetus results from destruction of target cells once they are formed. |
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Term
| Cytomegalic Inclusion Disease |
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Definition
• CNS abnormalities: microcephaly, mental retardation, spasticity, epilepsy, periventricular calcification
• Eye: choroidoretinitis and optic atrophy
• Ear: sensorineural deafness
• Liver: hepatosplenomegaly and jaundice which is due to hepatitis.
• Lung: pneumonitis
• Heart: myocarditis
• Thrombocytopenic purpura, Haemolytic anaemia
• Late sequelae in individuals asymptomatic at birth: hearing defects and reduced intelligence |
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Term
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Definition
• 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 antigenemia 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.
• 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. |
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Term
| CMV pp65 Antigenemia Test |
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Definition
| detected in nuclei of peripheral blood neutrophils |
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Term
| specimens for lab diagnosis of cmv |
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Definition
neonates- urine, saliva, serology IgM
adults- urine, blood, serology igG, IgM
pregnant women- serology IgG, serology IgM
immuno-compromised- urine, saliva, blood, tissue affected, serology IgG, serology IgM |
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Term
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Definition
• 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, foscarnet, and cidofovir. |
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Term
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Definition
• No licensed vaccine is available. There is a candidate live attenuated vaccine known as the Towne strain, but there are concerns about administering a live vaccine which could become latent and reactivate.
• Prevention of CMV disease in transplant recipients is a very complicated subject and varies from center to center. It may include the following measures:
– Screening and matching the CMV status of the donor and recipient
– Use of CMV negative blood for transfusions
– Administration of CMV immunoglobulin to seronegative recipients prior to transplant
– Give antiviral agents such as acyclovir and ganciclovir prophylactically |
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Term
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Definition
• Belong to the gamma herpesvirus subfamily of herpesviruses.
• Nucleocapsid 100 nm in diameter, with 162 capsomeres.
• Membrane is derived by budding of immature particles through cell membrane and is required for infectivity.
• Genome is a linear double-stranded DNA molecule with 172 kbp.
• The viral genome does not normally integrate into the cellular DNA but forms circular episomes which reside in the nucleus.
• The genome is large enough to code for 100–200 proteins but only a few have been identified. |
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Term
| epstein-barr virus epidemiology |
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Definition
• Two epidemiological patterns are seen with EBV.
• In developed countries, two peaks of infection are seen: the first in very young preschool children aged 1–6 and the second in adolescents and young adults aged 14–20. Eventually 80–90% of adults are infected.
• In developing countries, infection occurs at a much earlier age so that by the age of 2, 90% of children are seropositive.
• The virus is transmitted by contact with saliva, in particularly through kissing. |
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Term
| epstein-barr virus pathogenesis |
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Definition
• Once infected, a lifelong carrier state develops whereby a low-grade infection is kept in check by the immune defenses.
• Low-grade virus replication and shedding can be demonstrated in the epithelial cells of the pharynx of all seropositive individuals.
• EBV is able to immortalize B-lymphocytes in vitro and in vivo.
• Furthermore, a few EBV-immortalized B-cells can be demonstrated in the circulation which are continually cleared by immune surveillance mechanisms.
• EBV is associated with several very different diseases where it may act directly or one of several cofactors. |
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Term
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Definition
• Primary EBV infection is usually subclinical in childhood. However, in adolescents and adults, there is a 50% chance that the syndrome of infectious mononucleosis (IM) will develop.
• IM is usually a self-limited disease which consists of fever, lymphadenopathy, and splenomegaly. In some patients jaundice may be seen, which is due to hepatitis. Atypical lymphocytes are present in the blood.
• Complications occur rarely but may be serious, e.g., splenic rupture, meningoencephalitis, and pharyngeal obstruction.
• In some patients, chronic IM may occur, where eventually the patient dies of lymphoproliferative disease or lymphoma.
• Diagnosis of IM is usually made by the heterophile antibody test and/or detection of EBV IgM.
• There is no specific treatment. |
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Term
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Definition
• Burkitt’s lymphoma (BL) occurs endemically in parts of Africa and Papua New Guinea. It usually occurs in children aged 3–14 years. It responds favorably to chemotherapy.
• It is restricted to areas with holoendemic malaria. Therefore, it appears that malaria infection is a cofactor.
• Multiple copies of EBV genome and some EBV antigens can be found in BL cells, and patients with BL have high titers of antibodies against various EBV antigens.
• BL cells show a reciprocal translocation between the long arm of Chromosome 8 and Chromosomes 14, 2, or 22.
• This translocation result in the c-myc oncogene being transferred to the immunoglobulin gene regions. This results in the deregulation of the c-myc gene. It is thought that this translocation is probably already present by the time of EBV infection and is not caused by EBV.
• Sporadic cases of BL occur, especially in AIDS patients, which may or may not be associated with EBV.
• In theory BL can be controlled by the eradication of malaria (as has happened in Papua New Guinea) or vaccination against EBV. |
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Term
| Immunocompromised Patients ebv |
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Definition
• After primary infection, EBV maintains a steady low-grade latent infection in the body. Should the person become immunocompromised, the virus will reactivate. In a few cases, lymphoproliferative lesions and lymphoma may develop. These lesions tend to be extranodal and in unusual sites such as the GI tract or the CNS.
• Transplant recipients, e.g., renal: EBV is associated with the development of lymphoproliferative disease and lymphoma.
• AIDS patients: EBV is associated with oral leukoplakia and with various non-Hodgkin’s lymphoma.
• Ducan X-linked lymphoproliferative syndrome: This condition occurs exclusively in males who had inherited a defective gene in the X-chromosome. This condition accounts for half of the fatal cases of IM. |
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Term
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Definition
• Acute EBV infection is usually made by the heterophile antibody test and/or detection of anti-EBV VCA IgM.
• Cases of Burkitt’s lymphoma should be diagnosed by histology. The tumor can be stained with antibodies to lambda light chains which should reveal a monoclonal tumor of B-cell origin. In over 90% of cases, the cells express IgM at the cell surface.
• Cases of NPC should be diagnosed by histology.
• The determination of the titer of anti-EBV VCA IgA in screening for early lesions of NPC and also for monitoring treatment.
• A patient with nonspecific ENT symptoms who have elevated titers of EBV IgA should be given a thorough examination. |
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Term
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Definition
• A vaccine against EBV, which prevents primary EBV infection, should be able to control both BL and NPC.
• Such a vaccine must be given early in life. Such a vaccine would also be useful in seronegative organ transplant recipients and those developing severe IM, such as the male offspring of X-linked proliferative syndrome carriers.
• The vaccine should not preferably be a subunit vaccine since there is a danger that a live vaccine may still have tumorigenic properties.
• The antigen chosen for vaccine development is the MA antigen gp 340/220, as antibodies against this antigen are virus neutralizing.
• This vaccine is being tried in Africa. |
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Term
| Properties of HHV-6 And 7 |
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Definition
• Belong to the betaherpesvirus subfamily of herpesviruses.
• Double-stranded DNA genome of 170 kbp.
• The main target cell is the T-lymphocyte, although B-lymphocytes may also be infected.
• HHV-6 and HHV-7 share limited nucleotide homology and antigenic cross-reactivity.
• It is thought that HHV-6 and HHV-7 are related to each other in a similar manner to HSV-1 and HSV-2. |
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Term
| Epidemiology and Pathogenesis of HHV-6 and HHV-7 |
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Definition
• HHV-6 and HHV-7 are ubiquitous and are found worldwide.
• They are transmitted mainly through contact with saliva and through breastfeeding.
• HHV-6 and HHV-7 infections are acquired rapidly after the age of 4 months when the effect of maternal antibodies wears off.
• By the time of adulthood, 90–99% of the population has been infected by both viruses.
• Like other herpesviruses, HHV-6 and HHV-7 remain latent in the body after primary infection and reactivate from time to time. |
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Term
| clinical manifestations of HHV-6 and HHV-7 |
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Definition
• Primary HHV-6 infection is associated with roseola infantum, which is a classical disease of childhood.
• Most cases occur in infants between the ages of 4 months and 2 years.
• A spiking fever develops over a period of 2 days, followed by a mild rash. The fever is high enough to cause febrile convulsions.
• There are reports that the disease may be complicated by encephalitis.
• If primary infection is delayed until adulthood, there is a small chance that an infectious mononucleosis-like disease may develop in a similar manner to EBV
and CMV.
• There is no firm evidence linking HHV-6 to lymphomas or lymphoproliferative diseases.
• There is no firm disease association with HHV-7 at present.
• Although both viruses may be reactivated in immunocompromised patients, it is yet uncertain whether they cause significant disease since CMV is almost invariably present. |
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Term
| Diagnosis and Management of roseola infantum |
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Definition
• Rosela infantum has a very characteristic presentation, and a diagnosis can usually be made on clinical grounds alone.
• Therefore, very few virology laboratories offer a diagnostic service for HHV-6 or HHV-7 infection.
• The technique for virus isolation is complicated and thus not practicable as a routine diagnostic procedure.
• Therefore, serology is the mainstay of diagnosis where specific IgM and IgG are detected.
• There is no specific antiviral treatment for HHV-6 infection. |
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Term
| rubeola vs rubella vs roseola infantum |
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Definition
rubeola- ordinary measles, conjunctivitis, cough, coryza, fever, koplic spots on buccal mucosa, rash appears at the hairline and spreads cephalocaudally over 3 days
rubella- german measles, headache, low grade fever, sore throat, coryza, forchheimer spots on soft palate, lymphadenopathy, rash begins on the face and spreads cephalocaudally
roseola infantum- exanthem subitum, affects young children 6-36 months old, caused by human herpes virus 6, abrupt high fever, after fever subsides a rash develops starting on the neck and trunk and spreading to the face and extremities |
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Term
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Definition
• Belong to the gammaherpes viruses subfamily of herpes viruses.
• Originally isolated from cells of Kaposi’s sarcoma (KS).
• Now appears to be firmly associated with Kaposi’s sarcoma as well as some lesser known malignancies such as Castleman’s disease and primary effusion lymphomas.
• HHV-8 DNA is found in almost 100% of cases of Kaposi’s sarcoma.
• Most patients with KS have antibodies against HHV-8.
• The seroprevalence of HHV-8 is low among the general population but is high in groups of individuals susceptible to KS, such as homosexuals.
• Unlike other herpes viruses, HHV-8 does not have a ubiquitous distribution. |
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