Microbiology
Summary
Human herpesvirus 6 (HHV-6), a member of the Herpesviridae family, is a double-stranded DNA virus that primarily infects humans and is responsible for a disease called roseola. This disease, which is also called "sixth disease" and "exanthema subitum", primarily affects children aged 6 months to 2 years. A key characteristic of HHV-6 is that it infects CD4 cells, namey helper T-cells, which can lead to immunosuppression by reducing the CD4 cell population.
Roseola initially presents as a high fever that lasts for approximately 3-4 days and is subsequently followed by a diffuse macular rash, often with a lacy appearance that spares the face. The high fever associated with roseola, sometimes reaching over 104¬°F, can trigger febrile seizures.
Lesson Outline
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FAQs
HHV-6, or human herpesvirus 6, is a member of the Herpesviridae family. This DNA virus is the causative agent of roseola, also known as sixth disease or exanthema subitum. Roseola is a common childhood viral illness characterized by a high-grade fever followed by a distinctive skin rash.
Roseola typically begins with a sudden, high-grade fever that can last for several days. Once the fever subsides, a pinkish-red rash generally appears on the trunk and then spreads to the extremities. Roseola is diagnosed primarily based on the characteristic pattern of high fever followed by a rash. Laboratory tests to detect HHV-6 can confirm the diagnosis.
HHV-6 is primarily spread via saliva. It is most commonly transmitted amongst children, particularly those in daycare or school environments. The virus can also be spread through respiratory secretions during close contact with an infected individual. HHV-6 can remain inactive in the body and reactivate at a later time, particularly in times of stress or illness.
HHV-6 is a lymphotropic virus. It primarily infects CD4 cells, namely helper T-cells. Infection with HHV-6 can cause a decrease in CD4 cell numbers and potentially lead to an impaired immune response. Reactivation of latent HHV-6 can occur in immunocompromised individuals, leading to further health complications.
