Tissue for sectioning should be placed in a 
fixative as soon as it is removed from the 
body. 
c. Shipment of specimens 
Dry blood or tissue smears may be placed in 
slide boxes with tissue between and over the 
slides to prevent breakage. Slides may be 
wrapped in bundles, slide over slide, in toilet 
tissue with one or two layers of tissue be- 
tween adjacent slides. The slides may be 
packed in a mailing container or box with 
enough protective material to prevent break- 
age, but these containers should be packed 
in a box with additional packing material. 
d. Storage of specimens 
Prompt examination of blood specimens is 
desirable because blood loses its affinity for 
stain after 3 to 4 days. Unstained slides may 
be refrigerated a week, but, if staining is to 
be delayed, thin films should be fixed 
with methyl alcohol and thick films dehemo- 
globinized in buffered water before storage. 
Subsequent staining requires special technic. 
Prompt refrigeration of whole blood is nec- 
essary if it is not to be examined immedi- 
ately. Microfilariae remain alive in blood a 
week or more under refrigeration. Tissue or 
fluid smears, like thin blood films, may be 
stored in the refriegrator, after fixation with 
methyl alcohol, before being stained. 
Stained blood films, tissue impression 
smears, or fluid smears may be preserved by 
covering the film with a coverslio or a coat- 
ing of clear Diaphane or other neutral 
mounting medium. 
e. Immunodiagnostic tests in parasitic diseases 
The immunodiagnostic tests employed in 
parasite diagnosis are, in general, modifica- 
tions of procedures in common use, that is, 
complement fixation, precipitin, hemag- 
glutination, flocculation, or fluorescent anti- 
body technics. 
Various types of immunodiagnostic tests 
and the present status of their applicability 
in a variety of parasitic diseases are shown 
in Table 2. Specimens collected for serologic 
diagnosis of parasitic infections are taken as 
for other types of serologic tests. The serum 
should never be inactivated. If examination 
is to be delayed, 0.01 ml. of 1% aqueous 
solution of borated merthiolate per ml. of 
scrum may be added f Appendix II). If the 
serum is to be used also for virus serology, 
it must not be merthiolated. 
2. Intestinal Parasites. Diseases caused by intesti- 
nal parasites are diagnosed mainly by the exami- 
nation of fecal specimens, but urine or sputum 
may be used for diseases caused by certain 
species. Properly collected and preserved speci- 
mens are of utmost importance since old, or 
poorly preserved materials are of little value in 
establishing a diagnosis and may lead to errone- 
ous conclusions. 
a. Fecal specimens 
The stool should be collected in a clean con- 
tainer or on clean paper and transferred to 
a suitable container such as a half-pint waxed 
carton with an over-lapping lid. Urine must 
be excluded since it will destroy trophozoites 
if they are present. Feces deposited on soil 
are not satisfactory due to the possible pres- 
ence of free-living larvae and other con- 
taminants which may confuse the diagnosis. 
The specimen should be taken to the labora- 
tory at once; or if the examination will be 
delayed, a small portion, in addition to the 
carton specimen, should be placed in PVA 
fixative (polyvinyl alcohol) (Appendix II) 
to preserve trophozoites. Administration of 
barium, magnesia, or oil prior to collection 
will render a specimen unsatisfactory for ex- 
amination. 
b. Mailed specimens 
Specimens sent through the mail must be in 
containers which meet postal regulations for 
infectious materials. 
One-ounce, screw-cap vials placed in a metal 
case with a screw cap and enclosed in a 
cardboard container with a metal screw cap 
are satisfactory. The vials should be sealed 
with adhesive tape around the top to prevent 
leakage. They should then be packed in suit- 
able absorbent materials to prevent break- 
age from shock transmission and to absorb 
entirely any leakage that would result if 
breakage should occur. Mailed specimens 
require use of a preservative, and a two-vial 
method of collection and shipping is ad- 
vocated. One vial contains 5% or 10% 
formalin, the other PVA fixative. Thus the 
laboratory has a formalinized specimen that 
can be examined for cysts and helminth eggs 
and a PVA-fixed specimen that can be ex- 
amined for trophozoites, and to a lesser de- 
gree, for cysts. The method of handling a 
stool specimen for parasitological examina- 
tion is shown in Figure 2. 
22 
