ASTM E938-94
(Test Method)Standard Test Method for Effectiveness of Liquid, Gel, or Cream Insecticides Against Adult Human Lice
Standard Test Method for Effectiveness of Liquid, Gel, or Cream Insecticides Against Adult Human Lice
SCOPE
1.1 This test method determines the effectiveness of pediculicidal materials in liquid, gel, or cream form, against the adult human louse, Pediculus humanus , the surrogate subspecies for the human head louse ( P.h. capitis ). (Only gels or creams that liquefy at 32°C (90°F) can be tested).
1.2 This test method is for the use of those wishing to develop efficacy data, or to compare formulations for head louse control.
1.3 This test method consists of five replicates for a statistical comparison of formulations.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E 938 – 94
Standard Test Method for
Effectiveness of Liquid, Gel, or Cream Insecticides Against
Adult Human Lice
This standard is issued under the fixed designation E 938; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope both in terms of test insects and test procedures for the
gathering of efficacy data for pediculicides.
1.1 This test method determines the effectiveness of pedi-
4.2 Data collection in this manner should be suitable for
culicidal materials in liquid, gel, or cream form, against the
product development and comparison. In addition, it should be
adult human louse, Pediculus humanus, the surrogate subspe-
suitable for review by regulatory agencies.
cies for the human head louse (P.h. capitis). (Only gels or
creams that liquefy at 32°C (90°F) can be tested).
5. Apparatus and Materials
1.2 This test method is for the use of those wishing to
5.1 Test Container—A 9-dram plastic vial, screened at the
develop efficacy data, or to compare formulations for head
bottom with 20-mesh screen, shall be used as the dipping
louse control.
vessel. A plunger, made from a plastic rod, and a circular
1.3 This test method consists of five replicates for a statis-
screen fits inside the vial. Plastics used should be as chemically
tical comparison of formulations.
unreactive as possible. Plastic vials are to be discarded after
1.4 The values stated in SI units are to be regarded as the
each test.
standard. The values given in parentheses are for information
5.2 Beakers—A 100-mL beaker is used to contain the
only.
insecticide into which the test container is dipped. A1000-mL
1.5 This standard does not purport to address all of the
beaker is used as the container in which the lice are washed
safety concerns, if any, associated with its use. It is the
after treatment.
responsibility of the user of this standard to establish appro-
5.3 Heating Surface—A slide dryer, that will provide heat
priate safety and health practices and determine the applica-
of approximately 37°C (98°F), is adequate.
bility of regulatory limitations prior to use.
5.4 Incubator—The incubator shall be capable of maintain-
2. Terminology ing a temperature of 31.7°C (89°F) and 60 % RH.
5.5 Petri dishes, 8.9 cm in diameter and 1.3 cm deep.
2.1 Descriptions of Terms Specific to This Standard:
5.6 Waterbath—Capable of maintaining 32°C (90°F).
2.1.1 morbid—unable to move towards heat 1 h after
5.7 Dark Cotton Corduroy,4by4cm.
treatment: sickly, but not necessarily dying; may recover by 24
5.8 Paper Toweling, Stop Watch, Forceps or Camel Hair
h.
Brush, and Wash Bottle.
2.1.2 moribund—unable to move towards heat (and there-
5.9 Test Insect—The test insect is the human body louse,
fore food) 24 h after treatment; dying.
Pediculus humanus humanus. The present strain was estab-
3. Summary of Test Method
lished from the USDA Gainesville strain. It is a susceptible
strain and, through selection, has adapted to a rabbit host.
3.1 Five replicates of 25 lice each, plus five control repli-
5.10 Host Animal—New Zealand white rabbits.
cates for each batch of lice, shall be used for each test
concentration or any other variable tested.
6. Rearing of Test Insects
3.2 Percent mortality, corrected by Abbott’s Formula, is
6.1 Collect eggs at 2-day intervals. This can be done when
determined.
the corduroy patch is placed on the rabbit. The adult lice leave
4. Significance and Use
the patch to feed. The patch is then removed from the rabbit.
Any lice that do remain on the patch, should be removed.
4.1 This test method should provide a consistent approach
6.2 Place the patch containing eggs in a plastic container (10
by 7 cm) with a screened lid, and note the date on the container.
This test method is under the jurisdiction of ASTM Committee E-35 on
Place the container in an incubator that is maintained at 31.7°C
Pesticides and is the direct responsibility of Subcommittee E35.12 on Insect Control
and 60 % RH.
Agents.
Current edition approved June 15, 1994. Published August 1994. Originally
e1
published as E 938 – 83. Last previous edition E 938 – 83 (1988) .
2 3
Abbott, W. S., “A Method of Computing the Effectiveness of An Insecticide,” The present strain of Pediculus humanus humanus is maintained by Insect
Journal of Economic Entomology, Vol 18, 1925, pp. 265–267. Contr
...
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