Bee and wasp stings in Deniyaya; a series of 322 cases

To describe wasp and bee species that sting humans, analyse risk factors and clinical features.

A prospective observational study was conducted on patients presenting to Base Hospital Deniyaya with suspected bee and wasp stings from 2011 to 2013. Data were gathered using a questionnaire and specimens of offending insects collected for identification. When the insect specimen was unavailable, identification was made by the victim selecting (without prompting) from several dead specimens presented by the first author.

There were 322 patients (mean age: 42.5 years, SD: 15.1, 173 [53.7%] males). Insects were brought by 55 (17%) and 267 (83%) were identified using specimens. All occurred during day-time, 142 (44.1%) during August and September, and 200 victims (62%) were tea plantation workers. Majority (78.9%) reported a localized painful self-limiting swelling without systemic features and 15 (4.6%) developed anaphylactic shock. None died. Five specimens were available from those in anaphylactic shock (four Apis dorsata, one Ropalidia marginata). Vespa tropica stinging caused a characteristic skin lesion. Of the 55 specimens, 46 (83.6%) were Apis dorsata (Giant honey-bee, ''Bambara''), 8 (14.5%) Vespa tropica (Greater banded hornet, ''Debara'') and one Ropalidia marginata (Paper wasp, ''Kaladuruwa'').

Only three hymenoptera species stings were reported. Risk factors included day-time outdoor activities, occupation (tea plantation workers) and period of year. The latter may be due to pollen season when the insects are found in abundance. Only 4.6% of the patients developed anaphylactic shock. Vespa tropica stings led to a unique skin lesion.