The T-lymphotropic HHV-6 was first recognized in 1986. Initial isolations were made from cultures of peripheral blood mononuclear cells from patients with lymphoproliferative disorders.

Properties of the Virus

The viral DNA is about 160–170 kbp in size and has a mean composition of 43–44% (G + C). The genetic arrangement of the HHV-6 genome resembles that of human CMV.

HHV-6 appears to be unrelated antigenically to the other known human herpesviruses except for some limited cross reactivity with HHV-7. Isolates of HHV-6 segregate into two closely related but distinct antigenic groups (designated A and B).

The virus grows well in CD4 T lymphocytes. Other cell types also support viral replication, including B cells and cells of glial, fibroblastoid, and megakaryocyte origin. Cells in the oropharynx must become infected because virus is present in saliva. It is not known which cells in the body become latently infected. Human CD46 is the cellular receptor for the virus.

Epidemiology and Clinical Findings

Seroepidemiologic studies using immunofluorescence tests for serum antibodies or PCR assays for viral DNA in saliva or blood cells have shown that HHV-6 is widespread in the population. It is estimated that more than 90% of children older than age 1 year and adults are virus positive.

Infections with HHV-6 typically occur in early child hood. This primary infection causes exanthem subitum (roseola infantum, or “sixth disease”), the mild common childhood disease characterized by a high fever and skin rash. The 6B variant appears to be the major cause of this disease. The virus is associated with febrile seizures in children.

The mode of transmission of HHV-6 is presumed to be via oral secretions. The fact that it is a ubiquitous agent suggests that it must be shed into the environment from an infected carrier.

Infections persist for life. Reactivation appears to be common in transplant patients and during pregnancy. The consequences of reactivated infection remain to be determined. HHV-6 reactivation occurs in close to half of patients who undergo hematopoietic stem cell transplantation and can be detected using blood PCR. Those reactivations commonly occur soon after transplant and have been associated with delayed engraftment, central nervous system dysfunction, and increased mortality.

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم العلاقات العامة ينظّم برنامجًا ثقافيًّا لوفد أكاديمي من جامعة كربلاء

قسم الشؤون الخدمية ينفّذ حملة لتنظيف محيط مرقد أبي الفضل العباس (عليه السلام)

معهد القرآن الكريم النسوي يواصل برنامج الختمات القرآنية الرمضانية

ضمن برنامج يبلغون.. محافظة المثنى تشهد إقامة 8 مجالس قرآنية رمضانية

المزيد

الآخبار الصحية

الماء المملح.. فائدة حقيقية أم "صيحة زائفة"؟

عادة بسيطة تدعم الصحة وتحافظ على الوزن المثالي

الغذاء النباتي يقلل مخاطر السرطان.. مع استثناء مهم

الحليب قليل أم كامل الدسم.. أيهما أفضل؟

المزيد

الآخبار التكنلوجية

أنثروبيك تتحدى البنتاغون.. وترامب يأمر بوقف التعامل معها

ميزة جديدة من "إنستغرام" لحماية المراهقين من الانتحار

الأولى من نوعها.. "تقنية مذهلة" في هاتف سامسونغ الجديد

لماذا تشعر المرأة بالألم أكثر من الرجل؟.. دراسة تجيب

المزيد

مواضيع ذات صلة

HIV Infections in Humans: Laboratory Diagnosis

HIV Infections in Humans :Clinical Findings

HIV Infections in Humans : Pathogenesis and Pathology

Animal Lentivirus Systems

Classification of Lentiviruses

Viral DNA Is Integrated into the Host-Cell Genome in Some Nonlytic Viral Growth Cycles

Lytic Viral Growth Cycles Lead to Death of Host Cells

Viral Capsids Are Regular Arrays of One or a Few Types of Protein

Structure and Composition of Lentiviruses

HERPESVIRUSES

POLYOMAVIRUSES

Human T-Lymphotropic Viruses