These are mainly Thaumetopoea pityocampa schif. pine processionary
moth, Thaumetopoea processionea 1. oak processionary moth, Euproctis
chrysorrhoea brown-tail moth, Euproctis similis yellow-tail moth,
Animals most affected
Dogs, horses, pigs, (all animals).
The caterpillars infest pastures and fields. Animals may be affected by:
ingestion of the caterpillars as pupae or their irritant hairs (herbivores, dogs);
contact with the poisonous hairs whilst playing with the suspended nests which
hang under trees (puppies);
inhalation of the small hairs carried on the wind;
contact with underground nests (foraging pigs).
Incidences occur predominantly in spring (March-3une), when the caterpillars leave
their communal nests to feed.
Only the larvae at stages 3-5 are involved. Adverse effects occur due to the histamine-releasing
proteins (thaumetopoein in the case of the pine processionary moth) and other allergenic
compounds. Thaumetopoein is contained in the hairs which act as fine needles through
which the toxic compounds are injected.
Toxic doses not known.
Clinical features and lesions
Occur mainly in the buccal and perioral areas:
stomatitis, glossitis, pharyngitis developing over 2-3 days;
ulceration, progressing to necrosis of the tongue;
elongated mucosal erosions in the mouth;
oedema of the lips and oropharytix, hypersalivation.
Occasional general reactions may develop:
Local dermal reactions:
pronounced erythema in the form of acute eczema.
The following have also been observed:
in poultry: an acute, possibly severe enteritis, occurring particularly if
the caterpillar has been ingested;
in horses: enlongated mucosal erosions in the mouth, colic, nervousness and
agitation, progressing to agression, followed by a pronunced pruritus along the
No antidote. Symptomatic care only.
locally applied (topical) and general antihistamines;
oral antibiotics (spiramycin) for the mouth and surrounding areas;
local disinfection nd topical anaesthesia;
where the tongue is involved, injection in situ of the calcium heparinate
to limit the extent of the necrosis (due to infarcts).