Clinical Description of Infection

HHV-6B is the principle cause of the exanthem roseola infantum (exanthem subitum), an illness characterized by high fever and development of a rash after fever resolves.[8] HHV-7 can also cause roseola. However, the majority of children with HHV-6B or HHV-7 infection develop an undifferentiated fever, but this may be complicated in some by febrile convulsions, encephalopathy, and hepatitis. Primary infection is rare in adults but can occur including an infectious mononucleosis-type illness.

These viruses are ubiquitous and frequently reactivate. Proof that viral replication is causal in specific disease associations is usually lacking. The greatest attention has focused on links between HHV-6A and multiple sclerosis and HHV-7 and the skin rash pityriasis rosea. Links between HHV-6/HHV-7 and chronic fatigue syndrome have not been substantiated by molecular techniques.

Interactions between HIV-1 and HHV-6A, HHV-6B, or HHV-7 replication occur. Each of the herpesviruses can up-regulate or down-regulate HIV-1 replication under specific conditions, but the significance is uncertain. HHV-6 infection in the first year of life has been associated with more rapid HIV-1 disease progression in vertically infected infants. HHV-6A may contribute to the switch between CCR5 (M-tropic) and CXCR4 (T-tropic) virus late in HIV-1 infection. Reactivation of HHV-6A, HHV-6B, or HHV-7 in immunosuppressed transplant recipients can induce clinical syndromes including undif-ferentiated febrile illness, cytopenias, hepatitis, enceph-alopathy, rash, or pneumonitis. Indirect effects of reactivation of these viruses, posttransplantation may be more frequent and include increased HCMV replication, increased severity of HCMV disease, enhanced immuno-suppression leading to fungal superinfection, and in association with HCMV graft dysfunction or rejection.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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