Acute corrosion of the oral mucosa in a dog due to ingestion of Multicolored Asian Lady Beetles (Harmonia axyridis : Coccinellidae)

Abstract

A six-year old mixed-breed dog presented with severe trauma to the oral mucosa suggestive of chemical burn. Sixteen Harmonia axyridis (Coccinellidae) were removed from the oral cavity, which revealed trauma consistent with chemical burn. The beetles had become embedded in mucosa covering the hard palate and required manual removal. A diagnosis of beetle induced chemical burn was warranted and consistent with the nature of the chemical constituents of H. axyridis hemolymph.

Full text

Short communication
Acute corrosion of the oral mucosa in a dog due to ingestion
of Multicolored Asian Lady Beetles (Harmonia axyridis: Coccinellidae)
Ian C. Stocks
a
,
*
, Derek E. Lindsey
b
a
Department of Entomology, Soils, and Plant Sciences, Clemson University, Clemson, SC 29634-0315, USA
b
Clemson Animal Hospital, 108 Liberty Drive, Clemson, SC 29631-1615, USA
article info
Article history:
Received 16 January 2008
Received in revised form 8 February 2008
Accepted 8 May 2008
Available online 3 June 2008
Keywords:
Harmonia axyridis
MALB
Piperidine
3-Hydroxypiperidin-2-one
abstract
A six-year old mixed-breed dog presented with severe trauma to the oral mucosa sugges-
tive of chemical burn. Sixteen Harmonia axyridis (Coccinellidae) were removed from the
oral cavity, which revealed trauma consistent with chemical burn. The beetles had become
embedded in mucosa covering the hard palate and required manual removal. A diagnosis
of beetle induced chemical burn was warranted and consistent with the nature of the
chemical constituents of H. axyridis hemolymph.
Ó2008 Elsevier Ltd. All rights reserved.
1. Introduction
A 22 kg mixed-breed bitch presented with a foul odor
emanating from the mouth. Examination of the mouth
revealed 16 Harmonia axyridis (Pallas) (Multicolored Asian
Lady Beetle, MALB; family Coccinellidae) embedded in
the hard palate, and damage (Figs. 1–3) to the oral and
pharyngeal mucosa consistent with chemical burn. The ab-
solute number of ingested beetles is unknown, nor the
amount, if any, that actually passed into the stomach. The
dog did not have a prior history of foreign object ingestion,
and given the foul smell of MALB, it is surprising that a dog
would attempt to ingest them. Coincidental ingestion of
household chemicals was ruled out after interview with
the owner, but the dog had been on a course of oral anti-
flammatory drugs (Carprofen) for cruciate condition, so
the possibility exists that the dog presented with a rare
drug-interaction phenomenon with one or more of the
compounds in the beetle’s hemolymph. An unremarkable
recovery and the absence of signs other than those limited
to the mouth area suggest that there were no systemic
sequalae. However, based on what little data are available,
there appears to be the possibility of severe systemic effects
if sufficient numbers of MALB are fully ingested.
2. Discussion
The veterinary implications of non-ectoparasitic insect
species have become increasingly well known in recent
years. Red imported fire ants (RIFA – Solenopsis invicta
Buren, Formicidae) can cause trauma to both domestic
pets and livestock (Conceiça
˜o et al., 2006). Cantharidosis
in horses (cantharidin poisoning caused by ingestion of
blister beetles, family Meloidae) is now a well-known
and well-studied phenomenon (Schoeb and Panciera,
1979). Ingestion of >0.5 l of assorted beetles (primarily
Carabidae and Scarabaeidae) by a captive Beluga whale
induced the emetic voidance of the lining of the forestom-
ach, a reaction attributed to chemical trauma caused by
the release from the beetles of irritant chemicals, including
formic-, capric-, tiglic-, and methacrylic-acids, benzoqui-
nones, and assorted alkane hydrocarbons (Eisner and
Dalton, 1993).
Multicolored Asian Lady beetles have been a medical
concern for several years, and there is now evidence that
*Corresponding author. Tel.: þ1 864 656 3035.
E-mail address: ians@clemson.edu (I.C. Stocks).
Contents lists available at ScienceDirect
Toxicon
journal homepage: www.elsevier.com/locate/toxicon
0041-0101/$ – see front matter Ó2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.toxicon.2008.05.010
Toxicon 52 (2008) 389–391

they also pose a veterinary concern. This species is native to
Asia, but by 1994 MALB had become established through-
out most of North America (Koch, 2003). Until recently
MALB was treated mainly as a nuisance species because it
can enter homes by the thousands in winter months and
cause inconvenience and minor damage. Reports in the
medical literature in recent years suggest that MALB is re-
sponsible for allergy-related health problems, such as hy-
persensitivity to protein, IgE-mediated, allergens (Albright
et al., 2006). Allergen exposure during MALB infestations
can result in allergic rhinoconjunctivitis, scleral chemosis,
and contact-based facial angioedema (Davis et al., 2006).
Coccinellid beetles, including MALB, also synthesize and
store in their body fluid (hemolymph) an array of noxious
chemicals that serve as a defense mechanism against pred-
ators (Glisan-King and Meinwald, 1996). Body fluid can be
released either by trauma to the beetle or as part of a defen-
sive reaction known as reflex-bleeding (also known as
autohemmorhage), wherein the beetle deliberately rup-
tures membranes in the leg joints and expels droplets of
hemolymph fluid. Almost all coccinellid beetle species
could potentially pose human and veterinary risk, but cur-
rently only MALB is a concern because its behavioral ecol-
ogy predisposes it to associate with man-made structures
in large numbers at certain times of the year.
A major class of defense chemicals is the alkaloids and
their derivatives, including those that impart the repellent
Fig. 2. Sloughing of the mucosa of the hard palate.
Fig. 1. Harmonia axyridis (MALB) embedded in hard palate mucosa. Note the
color variation (polymorphism) amongst individuals.
Fig. 3. Chemical burn on the tongue.
I.C. Stocks, D.E. Lindsey / Toxicon 52 (2008) 389–391390

odors characteristic of coccinellids, such as 3-alkyl-2-
methoxypyrazine (Laurent et al., 2005). Experimentally
determined total methoxypyrazine content for MALB
revealed w33
m
g per beetle (0.98
m
g/mg, given an average
weight of 34.0 mg per MALB). Although many alkaloids
are capable of causing chemically induced damage to soft
tissues and toxicity after ingestion, the piperidine-based
alkaloids are particularly potent. Piperidine (C
5
H
11
N) has
a characteristic pepper-like odor, and both piperidine and
piperidine derivatives are naturally occurring plant and
animal compounds. The Material Safety Data Sheet
(MSDS) for piperidine lists it as a severe irritant if inhaled
or swallowed, leading to contact burns and blindness if
applied to the eyes. The Lethal Dose (LD50) ratings range
from 30 mg/kg for oral ingestion (mouse) to 276 mg/kg
for administration onto skin (rabbit). Other piperidine
derivatives of veterinary concern include those derived
from hemlock (Conium species; e.g., coniine, resulting in
neurotoxicity after ingestion) and RIFA venom (Solenop-
sin-A; trans-2-methyl-6-n-undecylpiperidine, resulting in
dermonecrosis and cytotoxicity at sting site).
The piperidine derivative 3-hydroxypiperidin-2-one
was isolated from MALB in experiments to identify com-
pounds for therapeutic use, and was found to be signifi-
cantly cytotoxic against several solid-tumor lines (Alam
et al., 2002). No reports can be found in the literature
that address the veterinary or medical implications of
either ingestion of this compound or the result of hemo-
lymph contact with soft tissues, but given that it is an
hydroxylated piperidine backbone, the compound should
react similarly to many other modified piperidines that
have contact, inhalation, and ingestion warnings for their
MSDS reports. Neither the average amount of 3-hydroxypi-
peridin-2-one nor the total amount per beetle of piperidine
alkaloid derivatives is known for MALB.
MALB is, and will continue to be, an element of the
insect fauna with which humans and their pets will have
occasional interactions. Currently, MALB is the only species
of lady bird beetle whose behavioral ecology predisposes it
to cause significant problems. Unfortunately, MALB is
highly polymorphic in color and pattern (Figs. 1–3), and
recognizing any single individual as MALB may be difficult
for both the layperson and veterinarian. Furthermore, there
is no consensus in the pest-control community regarding
the best method for eradicating MALB infestations, al-
though the concerns raised by most techniques are due to
aesthetic (staining of upholstery, etc.) or allergy-related
reasons. Many university and state extension agencies
provide fact-sheets that discuss the biology and control of
nuisance insects, and they can be consulted for further
reference regarding control options.
Acknowledgements
ICS acknowledges partial funding from the Southern
Plant Diagnostic Network and Drs. J.C. Morse and P.H. Adler,
who reviewed the manuscript.
Conflict of interest
The authors state that they have no conflicts of interest.
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