Association of HSV and Alzheimer’s Disease

An infectious agent or predisposing factor has longbeen HSV-1, a neurotropic virus that is almost
been sought for many neurological disorders, includingubiquitous in the human population. HSV-1 also shows
the insidious and debilitating Alzheimer’s diseasea predilection for infection of anatomical sites of the
(AD). Herpes simplex virus type 1 has been studiedbrain that are commonly damaged in AD.
extensively as a candidate for an aetiological agentFirst suggested by Ball in 1982, HSV-1 has since been
due to its ubiquitous and neurotropic nature, and theestablished as a prominent risk factor for AD. Other
similarity of the sites of human brain infection and ADpathogens, including herpes virus family members,
pathologies.have been investigated, but currently, HSV-1 is the
Collectively, current research indicates that HSV-1only infectious agent thought to have a possible
infection of the brain, although not the cause of AD,association with AD development.
is a significant risk factor, potentially predisposingA considerable number of studies have been
individuals to increased inflammation, neuritic plaquecompleted over the past 20 years to assess
and neurofibrillary tangle formation and beta-amyloidwhether or not the presence of HSV-1 in the aged
deposition.brain is associated with AD using increasingly more
Alois Alzheimer described the salient clinical featuressensitive techniques. Although there are some
of AD in 1907 through a case report of progressivecontradictory findings, by and large, the studies
dementia in a psychiatric patient in his care. Hisindicate that HSV-1 is found commonly in the brains
patient, Auguste D, probably suffered from many ofof individuals who had AD. Greater variability and a
the classic symptoms of this disease, includinglower frequency of HSV-1 detection was found in
memory loss, paranoid and altered behaviours,the earlier studies that employed less sensitive
reduced higher intellectual functions and loss oftechniques.
linguistic ability.With the advent of more sensitive polymerase chain
Alzheimer’s report marked the beginning ofreaction (PCR) techniques, the consistent detection
almost 100 years of clinical and research effortof HSV-1 has indicated a strong correlation between
designed to establish both an understanding of theHSV-1 in the brain and AD. The more recent
aetiology of this insidious neurological disorder and thePCR-based studies also indicated that HSV-1 is found
development of a cure. Substantial progress has beenat fairly high frequency in normal aged human brain,
made but the search for the causative agentsbut is absent from most younger human brain
continues.samples examined.
As a consequence of the investigation into theAn absence of central nervous system
aetiology of sporadic AD, many risk factors(CNS) infection by another member of the
associated with the development of AD have beenherpes virus family (varicella zoster virus) was also
identified, including age, head injury accompanied byestablished, supporting the association of HSV-1 with
loss of consciousness, and a family history of AD,AD. HSV-1, on its own, is not the sole causative
which suggests the involvement of commonagent because AD develops in a subset of those
environmental factors.individuals with evidence of CNS infection but it is an
Although they remain controversial, protectiveestablished risk factor for AD.
factors have been identified also and these include anOutbreakBalm-Rx is a potent anti-herpes agent vital
increased level of education, hormone replacementin the treatment of HSV. Topical application of this
therapy in women, and the use of anti-inflammatoryantiviral treatment inhibits and kills the herpes virus,
drugs. Despite these advances in our understandingmaking it an important and versatile remedy for
of the disease, no single causative agent has beenhome use in the fight against herpes. It therefore
established for the more common, sporadic form ofcomes as no surprise that application of this product
AD.during prodrome, the tingling before an outbreak, can
Due to the common and neurological nature ofprevent herpes blisters forming, aborting the pending
sporadic AD, neurotropic and ubiquitous candidateflare up altogether.
pathogens were investigated. A prime candidate has