A new skin- allergy causing moth species (Toxoproctis hemibathes) and the study of its impact on the residents of Mukim Labis and Mukim Bekok, Johor

A population outbreak of the moth species identified taxonomically as Toxoproctis hemibathes (Family Lymantriidae) had occurred between 9-16 August 2007, triggering allergic reactions manifested as skin rashes, intense itchiness and dermatitis among the local residents of Mukim Labis and Mukim Bekok, in Peninsular southern state of Johor. Follow-up surveys of the allergic incident were conducted from 22 to 26 November 2008 involving 161 afflicted respondents comprising different age, gender, ethnicity and occupational groups. Results of the studies showed that the allergic reactions mostly involved young people within the age range of 10 to 19 years old (24.2%), especially males (59.0%), Malays (63.4%), school children (32.3%) and local residents of Mukim Labis (59.6%), and particularly workers of the North Labis plantation (28.6%). The most prevalent allergic symptoms were intense skin itchiness (98.1%) and skin rashes (99.4%), with the majority manifesting mild allergic reactions (73.0%) lasting between 1 to 7 days (76.0%). The problem also involved interrupted sleep (92.5%), loss of appetite (5.0%), and other ailments (7.5%), which required medical leave (19.3%). About 98.8% of the afflicted respondents applied self cures using modern drugs and ointments (93.8%) and 62.7% used commercial insecticides to eliminate the moth population outbreaks. The moth species identified, Toxoproctis hemibathes, was a new record for Peninsular Malaysia. Further data analyses found significant positive correlations between the severity of allergic symptoms and gender (p=0.042) as well as ethnicity (p=0.007). However, the prevalence was confined to the local residents of mukim Labis only, particularly those in the North Labis plantation. This outbreak was an isolated case, and thus, further studies should be conducted to determine the actual cause and mechanisms invloved in the allergic reactions triggered by this particular species of moths.