56 S.-Afr. Tydskr. Dierk. 1980, 15 (I) skin. Each spine can function effectively only twice (Gilmer Urticaria caused by the slug 1925). caterpillar Latoia vivida On contact with the skin there is a sharp jabbing pain which quickly reaches a maximum intensity. The pain (Lepidoptera: Limacodidae) gradually subsides and is followed by a poorly circum­ scribed paraesthesia and local itchiness (Fig. 2). An urti­ carial reaction becomes apparent after 8 min, reaches 8 P.B. Fourie· and P.R. Hull maximum 25 min after contact with the poison, and dis­ Photobiology Research Unit of the MRC, Department of Dermatology, appears within 2 h with no constitutional side effects. Test University of Pretoria. Pretoria 0002, South Africa. fields on the skin of a volunteer were topically pre-treated P.D. Fourie with various pharmacological agents including anti­ ,Prerent address: Tuberculosis Research Institut.e of the MRC, histamine, atropine, theophyUin and a corticosteroid. When Private Bag X385, Pretoria 0001 South Africa the live caterpillar was allowed to sting the test areas the ·To whom oll correspondence should be addressed. reaction was blocked by the antihistamine and the corti­ Received 6 August 1979; a.cccpt.ed 24 August 1979 costeroid. Histamine and histidine alongside some unidentified sub­ Larvae of the moth LaJoia vivida (family Limacodidae) stances were demonstrated on thin layer chromatographY, have spiny tubercles which cause sharp pain and subse­ quent urticaria upon contact with human skin. This study These were separated with butaAol-acetic acid against a set of 20 pure concentrates of known amino acids, dried and describes the sting's clinical consequences and evaluates the etTect of various pharmacological modifiers on the clinical stained with ninhydrin for inspection under ultra-violet light. response. Several Lepidoptera larvae produce irritating and some­ L. vivida is widely distributed in South Africa, except for times dangerous toxins (Picarelli & Do Va.lle 1971). Most of the Cape Province and most parts of the Orange Free State the species CAuse burning pain and a rash or urticaria. (Pinbey 1975). In urban gardens the slug caterpillars Although various substances have been identified in the usually live on privet, rose and prune leaves. The cater­ toxins of these caterpillars (Picarelli & Do Valle 1971; pillars are light green in colour and approximately 2,5 cm Rothschild, Von Euw & Reicbstein 1972), little is known long in the fInal larval stadium. A striking feature is the about the venom of the Limacodidae. Histamine is common . pointed bollow tubercles armed with prominent spines. A in many toxin·producing insects and invertebrates, and its ) 0 single large poison ceU occupies the greatest part of the presence in the slug caterpillar is nol surprising. It alone 1 0 tubercle lumen. Some of the spines possess setae but most cannot be responsible for the intense pain and 'symptomatic 2 d terminate in sharp stylets (Fig. I). Upon contact the distal results (Valle, Picarell.i & Prado J 954). This was confirmed e t portion of the spine breaks otT and releases poison into the by comparing the effects of slug caterpillar toxin extracls a d and histamine on small superficial cuts in the skin. Acetyl ( r choline, proteins and proteolytic enzymes may be can­ e h s didates for evoking the characteristic burning sensation i l b (Goldman el a/. 1960; Beard 1963; Frazer 1965; De Jong, u Bleumink & Nater 1975). P e h t y Reter.ences b d BEARD, R.L. 1963. Insect toxins and venoms. Ann. Rev. £nl. 8: 1-18. e t DEJONG, M.CJ.M., BLEUMINK, E. & NATER. l.P. 1975. n a Investigative studies of the dermatitis caused by thl! larva of the r FIg. I Lateral view of the slug caterpillar La/Ola vivida to show spiny g browo-taiJ moth (Euproelis ehrysorrhoeo LinD.) I. Clinical and tubercles arranged in longitudinal row&. Note lack of alxlominal legs.. e experimental rtndings. Arch. Denn. Res. 253: 287-300. c n FRAZER, l.P.S. 1965. The cause ofurticauon produced by larval hair! e c i of A rclla eqja (L.) (l.epidoptera:Arcti.ida.e). Proc. R. enJ. Soc. Lond. l r (A) 40: 96-100. e d G ILMBR, P.M. 1925. A comparative study of the poison apparatus or n cc:rt.ain lepidopterous larvae. AM. En/omal. Soc. Am. 18: 203-239. u y GOLDMAN, L .• SAWYER, P., LEVINE, A., GOLDMAN, l., a GOLDMAN. S. & SPINAGER. J. 1960.lnvestigative studies of skin w e irrit.arion from caterpillars. J. Invt!SJ. Demw.lol. 34: 67-79. t a _.- I PICARELLI, Z.P. & DO VALLE,J.R. 1971. Pharmacological studies G I t I 00 caterpillar venoms. In: Venomous animals and their venomS e I Vol. 3, (OOs) Bilcher~ W. & Buck:]ey, f.E. Academic Press, New York. n i I b I PINHEY, E.C.G. 1975. Moths of Southem Africa. Tafelbcrg Publishers, a --- S Cape Town, South Africa. y 234 5 6 7 8 9 10 11 12 ROTHSCHILD, M., VON EUW, 1. & REICHSTEfN, T. 1972. Some b warningly d minules problems connected with roloured insects and toxic defense e c Fig. 2 Diagram.matic representation of pain scnsatiOIl: against time after mecbanisms. Mitt. Basler Afrika Bwl. 4: 135 - IS 8. ' . , u skiD contact with slug cat.erpillar venomous spines. The height of the d VALLE, l.R., PICARELLI, Z.P. & PRADO, J.t. 1954. Histamine o graph is arbitrary. content and pbarmacological properties of crude extracts from setae r p --burning pain; --- paraesthesia; and _. - itch. of urticating caterpillars. A rch. fill. pharmacodyn, 98; ) 24 - )34. e R.