Page 161 - International Space Station Benefits for Humanity, 3rd edition.

According to the Centers for Disease Control and The herpes viruses are already present in astronauts,
Prevention, one million cases of shingles occur yearly as they are in at least 95 percent of the general adult
in the United States, and 100,000 to 200,000 of these population worldwide. Therefore, measuring the
cases develop into a particularly painful and sometimes appearance of herpes viruses in astronaut body fluids
debilitating condition known as post-herpetic neural- is critical. It is widely believed that various stressors
gia, which can last for months or years. The other associated with spaceflight are responsible for the
seven herpes viruses also exist in an inactive state in observed decreased immunity. Researchers at NASA’s
different body tissues much like VZV, and similarly they Johnson Space Center found that four human herpes
may reactivate and cause disease during periods of viruses reactivate and appear in body fluids in
decreased immunity. response to spaceflight. Due to the reduced cellular
The most common cause of decreasing immunity is immunity, the viruses can emerge from their latent
age; however, chronic stress also results in decreased state into active infectious agents. The multiplying
immunity, and an increased risk of the secondary viruses are released into saliva, urine or blood, and
disease, such as VZV-driven shingles. Chemotherapy, they can be detected and quantified by a method
organ transplants and infectious diseases, such as called polymerase chain reaction (PCR) for each
human immunodeficiency virus (HIV), also result in specific virus. The finding of VZV in the saliva of
decreased immunity. Thus, viral reactivation has astronauts was the first report of VZV being reactivated
been identified as an important indicator of clinically and shed in asymptomatic individuals, thus posing a
relevant immune changes. Studies of immune- risk of disease in uninfected individuals. However, the
compromised individuals indicate that these patients PCR assay requires large, complex equipment, which
shed EBV in saliva at rates 90-fold higher than found is not practical for spaceflight.
in healthy individuals. To overcome this obstacle, NASA developed a rapid
method of detection of VZV in body fluids, and a patent
application is currently pending. The new technology
requires a small sample of saliva, which is mixed
with specialized reagents that produce a red color
only when VZV is present. This technology makes
possible early detection, before the appearance of skin
lesions. Early detection allows for early administration
of antiviral therapy and thus limits nerve damage and
prevents overt disease. The device is designed for use
in doctors’ offices or spacecraft and can be modified
easily for use with other viruses in saliva, urine, blood
and spinal fluid. The sensitivity and specificity emanates
from an antibody-antigen reaction.
In another collaborative study, NASA and University
of Colorado Health Science Center (Denver) researchers
developed a tool that assessed stress hormones
during space shuttle missions. Saliva samples were
collected on individual filter paper strips and tested
once back on Earth. The test measured cortisol and
dehydroepiandrosterone (DHEA)—two important stress
and immune regulatory hormones. The filter paper
also can be used for proteins and other molecules
of interest in saliva. Booklets of these filter papers
now are being used in university and government
Varicella zoster-infected MeWo cells showing laboratories for remote saliva collection. These studies
typical herpes virus-induced, multinucleated giant
cells. Cultures are stained with acrydine orange demonstrate the potential value of bringing to the
to identify RNA (red) in the cytoplasm. public a technology that could prevent a painful and
debilitating condition in up to one million people each
Image credit: NASA
year in the United States alone.

147