Kairomones
produced by a host, and specifically human hosts, play a
major role in the host-seeking behavior of anthropophilic
female mosquitoes Because of the disease vectoring
capability of mosquitoes that feed upon human hosts, efforts
are being made to discover the identity of the chemical
compounds that are used in host-location. Multiple sampling
techniques for collecting and characterizing human odors
have been developed and used to compile a thorough
understanding of the volatile chemicals given off by human
skin. The sampling techniques mainly comprise collection of
chemical emanations in the gas phase with detection by mass
spectrometry. One means of allowing for sample
identification of highly polar compounds is the use of small
glass beads to collect residue from human skin. Although
this method does discriminate against highly volatile
compounds, it allows for solvent-free loading of the sample
and minimizes water deposition from perspiration. Use of
this technique has led to the isolation and identification
of over 270 compounds present in analyses of human
emanations. To adequately characterize the most volatile
compounds given off from the skin, purge and trap mass
spectrometry was employed to analyze headspace collections
of air above a human arm. This technique discriminates
against polar compounds, but combined with the glass bead
technique, provides a more exact compilation of human
produced compounds. Information obtained from these
complementary analyses has resulted in the discovery of
attractant blends for Aedes aegypti, Anopheles albimanus,
and Ae. albopictus. Effective blends do not involve the use
of carbon dioxide, except in the case of Ae. albopictus,
where a suitable substitute for carbon dioxide has not yet
been discovered. The best blends are either as efficient, or
more efficient than the human arm at attracting laboratory
mosquitoes when tested in a triple cage dual port
olfactometer. The blends are comprised of as little as two
compounds, but become more effective as the number of
attractant compounds is increased. Currently, the best
blends comprise three components. These are being tested in
the field as a way to enhance the efficiency of surveillance
traps. Some human-produced emanations have been found to
inhibit the attraction of mosquitoes to blends and to the
human arm; the potential for use of these in
attraction-antagonist technologies is being explored.
Index
terms: Aedes aegypti, Anopheles
albimanus, kairomones, attractants, GC/MS
Copyright:
The copyrights of this original work belong to the
authors (see right-most box in title table). This
abstract appeared in Session 15–MEDICAL AND VETERINARY
ENTOMOLOGY Symposium and Poster Session, ABSTRACT BOOK I
– XXI-International Congress of Entomology, Brazil,
August 20-26, 2000.