The oldest sitting member of the Senate, Sen. Dianne Feinstein, D-Calif., is recovering at home after a recent hospitalization secondary to the viral infection called shingles, according to multiple reports.
"I want to thank everyone for the well wishes and the hospital staff for providing excellent care," the 89-year-old senator tweeted on March 7.
"I’m recovering at home now while I continue receiving treatment and look forward to returning to the Senate as soon as possible."
CALIFORNIA SENATOR FEINSTEIN HOSPITALIZED IN SAN FRANCISCO
Roughly one out of every three people in the United States will develop shingles in their lifetime, according to the Centers for Disease Control and Prevention (CDC).
People generally only get shingles once in their lives, although it is possible to get it more than once.
The risk of the infection increases as people get older, with some 1 million getting the disease each year in the U.S, the agency added.
Fox Digital News discussed the affliction with an infectious disease specialist in order to share more information about the medical condition.
Shingles is a rash caused by a virus known as varicella zoster virus. It's the same virus that causes chickenpox, according to the CDC.
More than 99% of Americans born before 1980 have had chickenpox, even if they didn’t know they had it, per the CDC.
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After someone gets chickenpox, the virus stays "dormant" in the body, hiding out in the nervous system.
However, it can reactivate years later as the person ages or the immune system gets depressed, causing a painful rash known as shingles, the CDC also said.
"Chickenpox occurs when you first acquire the virus — historically, it was one of the childhood diseases that almost everyone had," Dr. Anna Wald, an infectious diseases specialist and professor at the University of Washington School of Medicine in Seattle, told Fox News Digital.
"Even after the illness and the rash resolves, the virus remains in the body," she said.
"When people are older, or immunocompromised, the virus can become active again, causing shingles or zoster."
If a person has shingles, he or she can spread the virus to other people who have never had chickenpox or never been vaccinated for chickenpox.
When these people touch the fluid blisters from the rash, they can later become infected, according to the CDC.
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"If they get infected, they will develop chickenpox, not shingles," the CDC notes on its website.
But these people may develop shingles later in life.
Those who have active shingles can reduce their risk of spreading the virus by covering their rash.
It usually takes about seven to 10 days for the rash to crust over, at which time people are no longer infectious, per the CDC.
The shingles rash is classically on one side of the face or body, which often can be diagnosed by its characteristic appearance of lesions that are fluid-filled on a red base along a nerve distribution, per the CDC.
"Typical signs and symptoms of shingles is a rash on part of the body, most often the trunk and almost always one-sided," Wald noted.
Pain or tingling often precedes the rash, which usually occurs several days before the rash appears.
"The rash tends to be painful, with pain often persisting for a long time after the rash resolves."
"The most common complication of shingles is long-term nerve pain called postherpetic neuralgia (PHN)," the CDC says on its website.
The rash can also affect the eye or brain and sometimes also other internal organs, Wald cautioned.
These complications include pneumonia, hearing problems, encephalitis (brain inflammation) and Ramsay Hunt Syndrome — which affected pop sensation Justin Bieber last year.
The syndrome affects the facial nerve near one of the ears, according to Mayo Clinic.
It is known by its classic presentation of three signs: paralysis on one side of the face; pain in the ear on the same side of facial paralysis; and vesicles, or fluid-filled blisters, in the outer part of the ear, according to previous research.
Since shingles is caused by a virus, medications directed against the virus — known as antivirals, such as acyclovir and valacyclovir — are prescribed to decrease the duration and severity of the illness, according to the CDC.
But the medications are most effective if they're begun as soon as the rash appears.
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Prevention is key with vaccination to prevent chickenpox and shingles.
"Effective vaccines are available to prevent both chickenpox — given in childhood, 2 doses; and for shingles — given to adults over the age of 50, also 2 doses," Wald noted.
"Some people will develop shingles despite the vaccination, but it is usually milder and much less common."