Parasitol Res (2012) 110:335–339DOI 10.1007/s00436-011-2495-0
Observations on effects of a neem seed extract (MiteStop®)on biting lice (mallophages) and bloodsucking insectsparasitizing horses
Saleh Al-Quraishy & Fathy Abdel-Ghaffar &Khaled A. S. Al-Rasheid & Julia Mehlhorn &Heinz Mehlhorn
Received: 26 May 2011 / Accepted: 10 June 2011 / Published online: 22 June 2011
Abstract The hair of 300 horses belonging to short hair and
was noted to last for up to 7 days if the horses were not
long hair races had been routinely treated during the last 3 years
with a neem seed extract (MiteStop®) in order to killmallophages (e.g., specimens of the genus Werneckiella). Itwas found that in all cases, a hidden infestation with these
biting lice had existed, which became visible when theproduct (diluted 1:20 with tap water) was brushed onto the
The name of the specimens of the insect order Mallophaga
hair. The mallophages left the body surface and became
comes from the Greek words for “wool eater,” although
visible as a fine “wooly looking” layer at the tips of the hair.
they do not eat wool but live on the surface of the skin of
Furthermore, this treatment stopped the forming of dandruff
mammalian animals and on the skin as well as among the
of the skin of the horses, which, in case of heavy mallophage
feathers of birds, feed on skin scales and feather coverings,
infestations, had looked like being powdered. Another
and/or even lick blood—being very host specific (Zlotorzycka
interesting result of the treatment was reported by the riders.
et al. With respect to their living sites, there are two
They described that the product had a considerable repellent
basic groups (“hairlings” and “featherlings”), which parasit-
effect on bloodsucking tabanids, mosquitoes, ceratopogonids,
ize either the hair of mammalians or the feathers of birds.
simuliids, as well as on licking flies. This repellency effect
With respect to the arrangement of their chewing mouthparts(mandibles) and their paired, rather short antennae, there aretwo groups (suborders): Amblycera (they possess antennae
mostly with five segments each lying in a groove along the
Department of Zoology, College of Science,
lateral side of the broad head, and their mandibles bite
horizontally), while in the case of the suborder Ischnocera,
the antennae with 3–5 segments remain clearly visible, and
the mandibles bite vertically. Different species of both the
Department of Zoology, Faculty of Science, Cairo University,
hairlings and featherlings belong either to the suborders
The most important mallophage of horses—Werneckiella
C. & O. Vogt Institute for Brain Research,
equi equi—belongs to the order Ischnocera and is found
worldwide, since horses were distributed onto each conti-
nent as means of transport since thousands of years and
with them traveled their parasites and other agents of
diseases (Murray Arundel ; Moreby ; Perris
Düsseldorf, Germanye-mail: [email protected]
; Foil and Foil The recently finally accepted
species Werneckiella equi (Price et al. 2003) has many
synonyms in older literature and was placed before in thegenera Damalinia, Trichodectes, or Bovicola. The malloph-
The product was freshly diluted prior to use: 100 ml of the
ages of mammalian hosts and thus W. equi are mostly
product was placed in a bowl and covered by about 2 l of
hidden at the bases of hair, so that mass reproduction is
tap water. After some stirring with a brush or a sponge, this
only seen at the late state when skin and/or hair have
2 l of ready-to-use solution was brought onto the hair, so
already severe damage. Therefore, the prevention of such
that the whole body was wet from the upper side of the
large populations is needed, which grow mostly during
hooves to the back, head, and face. Afterwards, it was
winter after infestations were acquired during summer on
controlled what happened. The horse owners reported their
the meadow by contact with other infested hosts or by
observations to the distributor and ordered further material.
using the same equipment (e.g., equipment or blankets;
The family owned horses of the authors and those of
Jones and DiPietro ). In cases in which animals have
neighboring riding stables were personally treated and
further hidden diseases, the population of the hairlings may
inspected by the authors. In heavy infestations, the
reach more than one million per horse or cow. Therefore,
treatment was repeated twice at 1-week intervals, which
regular schemes of treatment seem reasonable to prevent
were noted due to appearance of numerous dead malloph-
severe scabies-like skin appearances (focal alopecia, scal-
ages at the tips of the hair after the first treatment.
ing, crusts, excoriations, exudations, hair loss; Larsen et al. ; Fadok and/or even transmission of the RNAviruses of infectious anemia worldwide in endemic regions.
In general, the treatment of horses against mallophages isdone by body washing with typical insecticides (pyreth-
During wintertime when the horses were in stables, the
roids, carbamates, fipronil, triflumuron, avermectines,
number of mallophages increased—apparently due to an
imidacloprid, etc.; Rommel ; Eckert et al.
infestation by body contacts with other horses in the late
phase of the summer and after the last treatments or by
sharing riding equipment with other horses. All horses of
Sorrell et al. which in general requires a second
the present study were kept under good conditions; but
treatment due to the fact that the nits glued to the hair are
nevertheless, they were found to be more or less intensely
not or poorly affected. The present paper reports the
infested. This was diagnosed by intense combing/brushing
effects of a biological insecticide based on a neem seed
extract (MiteStop®) that has been shown to have a broad
Although in some publications it is claimed that malloph-
range of efficacy against many species of ticks, mites, and
ages mainly occur at special places (such as along the head,
neck, and lateral sides, but not at the lower limbs, tail, andears), the present study showed their presence at merely allportions of the body. However, clearly visible dermatological
symptoms such as alopecia, scaling, excoriations, exudations,crusts, lesions, etc., which might attract licking flies (and thus
potential transmitters of agents of diseases), were scarce evenin heavily infested horses. On the other hand, mallophage-
MiteStop® is a concentrate of a neem seed extract
infested places of the fur led to skin reactions such as local
developed by the university spin-off company Alpha-
trembling when these places are touched. This was apparently
Biocare (Düsseldorf, Germany). It is classified as a
a sign of pruritus or peculiar sensitivity at these places. When
biocide of the EU class 18. This concentrated water-free
inspecting the hair of the horses, in general, different
extract was freshly diluted 1:20 with tap water just prior
developing stages (nits, larvae, adults) of the species W. equi
equi were observed (Fig. ). This species belongs to the orderof Ischnocera (= from Greek: with tiny horns = antennae).
These adult stages were characterized by their typical broadhead with a rounded anterior front and one pair of eyes at the
Three-hundred horses belonging to long and short hair
head as well as by their large spiracles at the lateral sides of
races were treated each several times per year during the
the segments of the abdomen. The mallophages measured
last 3 years with the product beginning in springtime until
about 1.6 mm in the case of the rare males and 1.8–2 mm in
early December, when most of the outdoor bloodsuckers
females, while their heads reached a diameter of 0.3 mm
being nearly as broad as the broadest region of the dorsal-
had migrated from the body surface to the tips of the hair
tion of a female Werneckiellamallophage containing an egg
before being killed. Due to this effect, the hair appeared“wooly twisted.” When using a dry brush, the chitinouscarcasses of the mallophages could be combed down. Whenthey were collected on a towel, they appeared very dry. When combing the mallophages down in heavy infestations,a large amount of dandruff was also removed. It was notedby the researchers and by the different rider groups that evena single treatment reduced considerably the formation ofdandruff, which was even more reduced if the treatment wasrepeated twice at intervals of 1 week. Apparently, thetreatment stopped also the development of the larvae in thenits, since in treated horses, it took months until aconsiderable infestation was noted again. This fact isremarkable, since the normal development inside the eggs
ventrally flattened, but if fed, the ton-like swollen abdominal
takes only 5–10 days (Arundel , being followed by a
body consists of eight visible segments. Embryological
2-week period to reach the adult stages (Martini ;
studies indicated that there had been ten anlagen of full
Mehlhorn ), which live for about 1–2 months. The
abdominal segments, of which the first was reduced, while
females produce mostly in total about 100 eggs which
segments 8 and 9 were apparently fused, so that only eight
Practically all users reported that the application of the
The above-described treatment with MiteStop® led to
product MiteStop® led, in addition to its insecticidal
the observation that about 1 h after the application of the
activity, to a considerable repellency of tabanids, other
product to the hair, the tips of the latter were spotted with
bloodsucking insects, ticks, and even flies, when applica-
remnants of the bodies of the mallophages which apparently
tion of the product was done in midsummer prior to a ride.
Table 1 Use of insecticides in the treatment against horse mallophages
as a continuous strip byhelp of a syringe
The typical insecticides are mostly not registered for horses, but for cattle. Therefore, the veterinarian has to use them “off label”p.t. post treatment
It was furthermore reported that this protection was
even in mass infestations (which often occur under bad
persistent at least for 3 days; in some cases, even repellency
containment conditions of the horses). This led to the fact
that the industry did not care intensely for the development
In addition, there were observations that treated horses
of peculiar anti-lice products for horses. Therefore, true
were apparently not attacked by the so-called autumn mites
insecticides being used in other animals were adapted in
(the larvae of the mite species Neotrombicula autumnalis),
doses and in the way of treatment for horses (Table
which suck lymph just above the hooves and thus introduce
Especially phoxim and imidacloprid but also permethrin
numerous severely itching wounds. Several other users also
and triflumuron had been intensively tested to be useful for
reported that in those cases, when horses had lesions along
the upper side of the hooves—apparently due to infections
Hanssen et al. ; Sorrell et al. ; Lowden et al.
with fungi and/or bacteria—healing occurred during the
). Applications of other insecticides (used and regis-
tered for cattle) are also reported in these papers and in thetextbooks of (Rommel and Eckert et al. (However, all these true insecticides can only be obtained by
prescription of a veterinarian. This is apparently anobstacle, which prevents riders to treat this rather inappar-
Animals on the meadow are attacked by a large variety of
ent but in any way important dermatosis.
bloodsucking or licking ectoparasites belonging to the
The neem seed extract (MiteStop®), which has a broad
groups of ticks, mites, and insects. These ectoparasites,
range of efficacies (Schmahl et al. ), is on the other hand
often occurring in huge numbers, may parasitize for a few
freely available in horse supply shops and has, in addition,
minutes (temporarily) such as mosquitoes and flies, stay
the advantages that it repels biting insects and ticks and
some days such as ticks, or even permanently such as
apparently has reducing effects on wounds along the hooves.
bloodsucking lice (Anoplura) or biting lice (Mallophaga)
Furthermore, the positive effect of a treatment can be seen
(Hansen and Londershausen Mehlhorn et al.
soon after the treatment, since apparently the compound
makes the mallophages crawl onto the tips of the hair just
flying from one host to the other or ticks with a regular
before they die. Since 10% of the active ingredient of
change of hosts (as all temporary ectoparasites) have
MiteStop® is also included in shampoos against human head
developed the potential to transmit agents of diseases,
lice (Abdel-Ghaffar and Semmler Heukelbach et al.
permanent parasites such as lice are less often vectors of
Abdel-Ghaffar et al. the efficacy of MiteStop®
parasites, bacteria, or viruses (Mehlhorn ; Aspöck
against the bloodsucking lice of horses (Haematopinus asini)
). However, mass infestations with ectoparasites may
is also given, although in the present study, there was no
introduce severe clinical signs of different types of
search for these parasites, which might introduce consider-
dermatosis due to their biting and/or bloodsucking activi-
able blood loss in case that they occur in larger numbers.
ties. These diseases were connected with loss of blood,restlessness, skin pain, itching, exudations, and/or lesionsmostly leading to considerable loss of weight and/or loss of
We gratefully acknowledge the support of the
general fitness, which may make them more easy victims of
Center of Excellence of the College of Science at King SaudUniversity, Riyadh, Saudi Arabia.
severe infectious diseases, while the latter would run muchmore smoothly in non-infested animals.
The mallophages of the present study (W. equi equi) are
underestimated parasites of horses, since they are muchmore common than believed. The reasons for this neglect
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