Download Human simplex virus type 1 (HSV-1)

Human simplex virus type 1 (HSV-1)
Human herpesvirus 1 (HSV-1) most commonly causes Herpes labialis, the
medical term for cold sores. However, HSV-1 can cause a few other
diseases as well, including:
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Cutaneous herpes (herpes of the skin)
Genital herpes (HSV-1 can cause genital herpes, though HSV-2 is
the more common cause)
Gingivostomatitis (painful mouth ulcers)
Herpes encephalitis (inflammation of the brain)
Keratoconjunctivitis (inflammation of the cornea and conjunctiva in
the eye)
In people with depressed immune systems, HSV-1 can cause esophagitis
(inflammation of the esophagus), hepatitis (inflammation of the liver), and
pneumonia (inflammation of the lungs). Once an HSV-1 infection takes
hold, it will usually pass in time but rarely fully clears the body. People with
HSV-1 can usually expect symptoms from time to time throughout their
lives. HSV-1 is passed through direct physical contact.
Human simplex virus type 2 (HSV-2)
Human herpesvirus 2 can cause many of the same diseases as HSV-1.
While both the simplex viruses can cause both cold sores and genital
sores, most often HSV-1 is the cause of cold sores and HSV-2 affects the
genitals. HSV-2 is also the main cause of neonatal herpes, a potentially
devastating disease that can affect the face, eyes, mouth, skin, and internal
organs of newborn babies born to HSV-2 infected mothers. The disease is
so dreadful in infants and the infection is so common in women (1 in 5
American women carry the herpes virus) that HSV-2 is one of the routine,
mandatory tests that expectant mothers take. Like HSV-1, HSV-2 is passed
between people through physical contact.
Varicella-zoster virus (HHV-3)
Varicella-zoster (VZV) causes chickenpox and shingles (also called herpes
zoster). Chickenpox involves fever and itchy, fluid-filled blisters. It’s usually
a childhood disease, although adults who didn’t have it as children can also
get it. VZV is extremely contagious. It sticks around for about a week. Then
the symptoms disappear. However, the herpes virus isn’t permanently gone
but rather retreats to lie dormant in a large bundle of nerves called a
ganglion. In some people who’ve had VZV, it can reactivate later in life,
traveling down the nerve from the ganglion to erupt on the skin as
exquisitely painful blisters. Since nerves leaving the ganglion supply a
small strip of skin on one side of the body, the lesion forms a wedge-shape
that resembles a shingle (hence the name shingles). A vaccine against
VZV has greatly reduced the number of cases of chickenpox in children
and to some extent of shingles in adults.
Epstein-Barr virus (HHV-4)
Most people in the West know Epstein-Barr virus (EBV) by the disease it
causes: infectious mononucleosis, or simply “mono.” Infectious
mononucleosis is passed through saliva, which is why it’s often called the
“kissing disease”. However, people who share silverware and glassware
can also pass EBV. Infectious mononucleosis causes prolonged fatigue, a
sore throat, and swollen lymph nodes. Epstein-Barr virus also cause
swelling of the spleen, which makes the organ more prone to rupture. Quite
extraordinarily (and, thankfully, rarely), EBV can also cause a few types of
cancer, including nasopharyngeal carcinoma (nose/throat cancer) and
Hodgkin’s or Burkitt’s lymphoma (cancer of the lymphatic system).
Cytomegalovirus (HHV-5)
Cytomegalovirus (CMV) is very common. About two out of three people
have been exposed to the virus. We know this because random testing of
donated blood finds antibodies against CMV in about two thirds of samples.
In otherwise healthy people with intact immune systems, CMV doesn’t
usually cause many noticeable problems (other than a “mono” type of
disease in some people). However, cytomegalovirus can be particularly
destructive in two groups of people: newborns and people with weak
immune systems. Newborn CMV can affect various organs such as the
spleen, liver, and lungs. In severe cases, babies born with CMV can
experience hearing loss, vision loss, and mental retardation. In people with
weak immune systems, CMV can cause:
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Colitis (inflammation of the large intestine)
Hepatitis
Myocarditis (inflammation of the heart)
Nephritis (inflammation of the kidney)
Pancreatitis (inflammation of the pancreas)
Pneumonia
Retinitis (inflammation in the back of the eye)
Human herpesvirus 6 and 7 (HHV-6 and HHV-7)
These two herpes viruses are thought to cause relatively mild human
disease compared to the other herpes viruses. However, ongoing research
is attributing more (and more severe) diseases to these viruses. Both HHV6 and HHV-7 are known to cause roseola infantum, a rash common in
young children. In almost every case, roseola infantum causes a fever
lasting about three days followed by a diffuse rash, both of which go away
soon after without problem. HHV-6 may also cause middle ear infections
and, in rare cases, encephalitis.
Human herpesvirus 8 (HHV-8)
Epstein-Barr virus isn’t the only human herpes virus that can cause cancer.
HHV-8 has been found to be the causative agent in Kaposi’s sarcoma,
usually found in patients with HIV/AIDS. In addition to appearing in people
with AIDS, Kaposi’s sarcoma may occur in patients with cancer, those
being treated for cancer, and those taking powerful immunosuppressant
drugs. HHV-8 doesn’t cause significant or noticeable disease in people with
intact immune systems.