[7] HHV-7 infection also leads to or is associated with a number of other symptoms, including acute febrile respiratory disease, fever, rash, vomiting, diarrhea, low lymphocyte counts,[8] and febrile seizures,[9] though most often no symptoms present at all.
[17] Drug reaction with eosinophilia and systemic symptoms (DRESS) is a specific type of DIHS that may be linked to HHV-7 as the condition may develop in response to herpesvirus antigens.
In one dermatologic study, 33 skin biopsies were performed and HHV-7 was found at higher rates in lichen planus lesions.
[18] HHV-7 was also detected in 79.3% of cervical tissue examined, indicating that sexual contact may be a route of transmission for HHV-7.
[19] Notably, HHV-7 and HHV-6 were detected in 56.3% of unspecified encephalopathy cases examined, with more HHV-7 positive cells in the gray matter of the frontal and temporal lobes HHV-7 is typically present in astrocytes and oligodendrocytes in the cerebral cortex, deep nuclei, and cerebellum.
During infection, HHV-7 causes a loss of CXCR4 in CD4+ T-cells in addition to lowering intracellular Ca2+ flux and chemotaxis in response to stroll cell-derived factor 1 (SDF-1).
Among these include membrane leaking, the presence of lytic syncytia,[34][35] occasional apoptosis,[36] the supporting of latent infection,[37] and increases and decreases in levels of certain cytokines.
HHV-7 can be grown in various lymphocytes in vitro, but researchers have noted that the virus does not propagate well under laboratory conditions.
[10] While HHV-7 may not be linked to any specific diseases, some researchers emphasize that the virus is still clinically relevant as it causes significant complications in immunocompromised patients.
Some research suggests that acyclovir and anti-CMV drugs such as cidofovir and foscarnet may have some therapeutic benefit in HHV-7 infection.
There is a need for HHV-7 specific treatments, however, because broad-spectrum antivirals are typically toxic and thus unsuitable for prophylactic use.
[46] A 2014 Washington University School of Medicine's analysis of 102 healthy adults sampled at as many as five major body habitats found that HHV-7 was present in 98% of them, especially in the mouth.