41. In addition, the herpes simplex virus type 1 ( HSV-1 ) infection is associated with demyelination of nerves. 42. This derivative has become a new lead for clinical trials and is also active against herpes simplex virus 1. 43. Herpes simplex virus is also used as a transneuronal tracer defining connections among neurons by virtue of traversing synapses.44. Interferon alpha has been used for control of serious viral infections, such as widespread warts or herpes simplex virus . 45. About two-thirds of the people infected with HIV also carry herpes simplex virus type 2, the genital herpes virus. 46. About 45 million people are infected with herpes simplex virus type 2, the primary cause of sexually transmitted genital herpes. 47. The sores typically heal within 2 3 weeks, but the herpes simplex virus remains dormant in the facial nerve branches. 48. Herpes simplex virus type 1, or HSV-1, causes fever blisters on the mouth, while HSV-2 triggers sores on the genitals.49. During the 1960s and 1970s it was suspected that infection with herpes simplex virus was the cause of the disease. 50. In the natural host, the virus exhibits pathogenesis similar to that of herpes simplex virus ( HSV ) in humans.