Skin snips are the specimens of choice in 
infections with Onchocerca volvulus as the 
microfilariae do not appear in the blood 
stream. Tissue fluid obtained by puncture 
and aspiration of a nodule may also show 
organisms. 
f. Serum 
Immunodiagnostic tests for intestinal para- 
site infection are considered to be useful 
routine diagnostic procedures in only a few 
diseases, as shown in Table 2. 
ARTHROPOD-BORNE DISEASES 
(SPECIMENS FOR IDENTIFICATION 
OF ARTHROPODS) 
Arthropod ectoparasites play an important role in the 
transmission of plague, typhus, tularemia, spotted 
fever, relapsing fever, and several other diseases. Any 
specimen submitted should be divided, one portion to 
be used for identification and the other for isolation 
of any virus or rickettsia that may be present. The 
sample for identification should be preserved in, pref- 
erably, 70% alcohol or in 2% formalin. Samples 
for isolation should be collected alive and stored on 
dry ice until tested. Table 3 shows the method of pre- 
serving and handling insects and other arthropods 
according to the kind of examination to be made. 
TABLE 3 
Preserving and Handling Insects and Other 
Arthropods 
For Identification 
Moist 
Dry 
In 70% alcohol or 2% formalin 
Between layers of tissue 
or lens paper. Not cotton 
Ticks 
Mosquitoes 
Mites 
Flies 
Fleas 
True bugs 
Lice 
Wasps, bees 
Fly maggots 
Moths 
Spiders 
Mosquito larvae 
Small flies 
Bed bugs 
Ants 
Caterpillars 
Butterflies 
For Demonstration of Microorganisms or Antibodies 
Suspend in bottle of 1% sodium chloride solution. 
Ectoparasites usually are wingless arthropods. Ticks 
and mites have eight legs in the nymphal and adult 
stages. Fleas and lice are true insects with six legs. 
Fleas are very active jumping insects, compressed 
from side to side, with elongated legs adapted for 
jumping. Lice are more sluggish insects, depressed 
from top to bottom, with legs adapted for grasping 
hairs. Illustrations of various kinds of arthropods are 
shown in Figure 4. 
1. Ectoparasites. Ticks, mites, fleas, and lice 
should be collected from bedding, animal bur- 
rows, or birds’ nests with fine forceps, aspirators, 
or applicator sticks. They may be simply 
combed, brushed, or knocked off an infected 
animal. 
2. Flies and Mosquitoes. These arthropods may be 
collected with insect nets, aspirators, chloroform 
tubes, cyanide jars, light, bait, or fly traps. 
Barns, outbuildings, the under surfaces of 
bridges, or other adult resting places are the best 
areas in which to find these insects. Tubes for 
picking up live insects, holding cages, storage 
boxes, and bottles are illustrated in Figure 5. 
All specimens should be submitted unmounted, 
and large numbers of specimens may be mailed 
in pill boxes or similar containers. Specimens 
may be mailed wrapped between layers of lens 
paper or cleansing tisue with a layer of absorb- 
ent cotton next to the top and bottom of the 
box to absorb vibrations and prevent breakage. 
Do not ship mosquitoes or flies between layers 
'of absorbent cotton. If specimens are mounted 
for identification, they should be fastened with 
clear fingernail polish or liquid cement to an 
insect point or an insect pin. Larger flies may be 
pinned through the thorax. Poorly mounted 
specimens are worse than those unmounted. 
3. Arthropod specimens submitted for virus or 
rickettsia isolation. For this purpose it is of 
the utmost importance that ticks, mites, fleas, 
lice, mosquitoes, or other insects be collected 
alive, sealed in ampules or rubber-stoppered test 
tubes, and stored on dry ice until tested. If dr)' 
ice is not available, temporary storage in a me- 
chanical deep freeze chest is satisfactory. Col- 
lection or storage in chloroform tubes or cyanide 
jars is not permissible because these materials 
inactivate many viral and rickettsial agents. 
27 
