| Procedures
for individual specimens
Autopsy or
Biopsy Specimens
Autopsy specimens for virus isolation should be collected within 24 hours
after death. Samples (1.0-2.5 cm Tubes of tissue) from probable sites of
pathology are collected using separate, sterile instruments and separate
sterile containers for each specimen to avoid cross contamination. Tissues are
transported to the laboratory on wet ice or cold pack. If they cannot be
tested within 48 hours they should be frozen at less than 70 C.
Blood
Specimens
Although blood is not the optimal specimen for isolation of most viruses, it
may be used for the recovery of some of the vector-borne viruses,
Enteroviruses, and CMV. Specimens for virus isolation should be collected as
soon as a viral etiology is suspected, otherwise early neutralizing antibody
may prevent recovery of virus from the blood. Either serum or leukocyte
preparations may be used for viral isolation. For isolation of virus from
leukocytes, 8 ml of blood is collected into a tube containing an
anticoagulant. Although heparin is often used, it is reported to inactivate
herpes simplex virus, and therefore EDTA may be preferable as an
anticoagulant. For isolation of virus from the serum or blood clot, 8 ml of
blood is collected aseptically without an anticoagulant. Blood specimens
should be transported to the laboratory on wet ice or a cold pack, but not
frozen
Cerebrospinal
Fluids (CSF)
For virus isolation 3-4 ml of CSF should be collected no later than 7-10
days after onset of illness, placed in a sterile screw-cap tube without
collection medium, and transported to the laboratory on wet ice or a cold
pack. The specimen should be inoculated as soon as possible after collection,
or held at -70 C or lower, since viruses are very labile in this medium.
Cervical
Specimens
Specimens should be collected using a speculum. A swab is used to clear the
cervix of mucus, and is then discarded. A second swab is inserted about 1 cm
into the cervical canal, rotated, and then left in place for a few seconds to
absorb secretions. If lesions are seen, they are swabbed. The swab tips are
broken off in 3-4 ml of collection medium (Hanks BSS is satisfactory) in a
screw-cap container. The specimen is transported to the laboratory on wet ice
or a cold pack. If it cannot be tested within 48 hours it should be frozen
below -70 C.
Eye
Specimens
A swab moistened in sterile saline is used to collect secretions from the
palpebral conjunctiva. The swab tip should be broken off into 2-3 ml of viral
collection medium (Hanks BSS is satisfactory) and transported to the
laboratory on wet ice. Scrapings from the cornea or conjunctiva should
be collected by an ophthalmologist or other suitably trained individual, and
placed in 2-3 ml of collection medium (Hanks BSS is satisfactory) for
isolation attempts. Specimens not tested within 48 hours should be
frozen at below -70 C.
Rectal
Swabs
The specimen should be collected no later than 7-10 days after onset of
illness. A cotton or Dacron tipped swab is moistened with collection medium
free from serum, inserted 4-6 cm into the rectum and rubbed against the mucosa
until visible fecal material adheres to the swab. Two swabs should be
collected in this manner and the tips broken off in 3 - 4 ml of collection
medium. The specimen should be transported to the laboratory on wet ice or
cold pack. If the specimen cannot be tested within 48 hours, it should be
frozen at <= -70 C.
Saliva
A swab should be rubbed over the buccal mucosa opposite the upper molars in
the proximity of the Stensen's ducts, then over the floor of the mouth
anterior to the tongue. The swab tip should be broken off into 3-4 ml of
collection medium (Hanks BSS is satisfactory), then transported to the
laboratory. Specimens which cannot be tested within 48 hours should be frozen
at below -70 C. Saliva collected by aspiration or expectoration into a sterile
container also may be used for virus isolation.
Semen
Specimens
Semen specimens collected into sterile screw-cap jars should be sent to the
laboratory on wet ice or cold pack.
Stool
Specimens
Stool specimens for viral isolation attempts should be collected as soon as
possible, and usually no later than 7-10 days after onset of illness.
Enteroviruses may be excreted for weeks so if infection with these viruses is
suspected, stool specimens collected later than 10 days post onset may be
collected. Three to four grams of the specimen (2-3 tsp.) should be
placed in a sterile, screw-cap glass or plastic bottle. The specimen should be
transported to the laboratory on wet ice or cold pack. If the specimen cannot
be tested within 48 hours after collection, it should be frozen at -20 C to
-70 C. A temperature of
-20 C is satisfactory for specimens being tested
only for Enteroviruses.
Throat and
Nasopharyngeal Specimens
Virus isolation is most successful if respiratory specimens are taken within
the first 3 days of illness, and they should be collected no later than 5 days
after onset. For virus isolation, swabs from both the throat and nasal passage
should be collected. The pharynx is swabbed vigorously with a cotton swab
moistened with collection medium free of serum. (Hanks BSS is a good
collection medium). A dry swab is inserted into the nostril parallel with the
palate and gently rotated. The applicator sticks are broken off, leaving both
of the swab tips in a vial containing 2- 3 ml of collection medium. Ensure
that the swabs are broken off short enough so as not to interfere with proper
closing of the vial and causing leakage.
Specimens should be
transported to the laboratory on wet ice and inoculated as soon as possible.
If the specimens cannot be inoculated into cell culture within 48 hours,
specimens should be frozen at -70 C. Note, respiratory specimens should not be
frozen at -20 C temperatures as this will markedly reduce chances of isolating
respiratory viruses. In general, freezing should be avoided if possible.
Urine
Specimens
Urine specimens are generally tested only for Cytomegalovirus, although
Mumps virus, Adenovirus, and some other viruses can sometimes be found in
urine. The specimen should be collected at the onset of illness or as soon as
possible if congenital disease is suspected. Chances of recovering virus may
be enhanced by examining 2-3 consecutive urine specimens. Clean voided
specimens (10-20ml) are collected in sterile containers and transported to the
laboratory on wet ice or cold pack. It is particularly important that
specimens for CMV be transported to the laboratory as soon as possible after
collection. When submitting urine specimens it is very important to inform the
laboratory what viral agent is suspected.
Vesicular
Lesion Specimens
Vesicular fluids and cellular material from the base of lesions should be
collected for virus isolation during the first 3 days of the eruption.
Vesicles are washed gently with sterile saline and the vesicular fluids are
aspirated with a 26-gauge or 27-gauge needle attached to a tuberculin syringe,
or with a capillary pipette. The fluids should be diluted in 2-3 ml of
collection medium (Hanks BSS is satisfactory) to prevent clotting.
Alternatively, the cleansed vesicles may be opened and the fluids collected
from several vesicles may be collected onto a swab which is then broken off
into 2-3 ml of collection medium (e.g., Hanks BSS). Cellular material from the
base of the vesicles may be added to the vesicular fluids for virus isolation
attempts. The base of the opened vesicle is scraped with a scalpel blade,
without producing bleeding, and the cellular material is placed in collection
medium together with the vesicular fluid. Specimens should be transported to
the laboratory on wet ice or with a cold pack or frozen at <=70 C if they
cannot be inoculated within 48 hours.
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