Infestation with Tropilaelaps spp.

Description and importance of the disease: The mites in the genus Tropilaelaps are parasites of honey bee brood. Feeding on bee larvae and pupae causes brood malformation, death of bees and subsequent colony decline or absconding. Development requires about 1 week, and the mites are dispersed on bees. There are at least four species in the genus Tropilaelaps. Each species tends to be associated with a particular giant honey bee in Asia. Two species (T. clareae and T. mercedesae) are damaging pests of Apis mellifera. The other two species (T. koenigerum and T. thaii) appear to be harmless to A. mellifera. Identification of the agent: Molecular and morphological methods are available for identifying each species. An infestation by Tropilaelaps can be recognised either visually on bees or by examining hive debris. Irregular brood pattern, dead or malformed immatures, bees with malformed wings that crawl at the hive’s entrance, and especially the presence of fast-running, red-brown, elongated mites on the combs, are diagnostic for the presence of T. clareae and/or T. mercedesae. An early diagnosis can be made after opening brood cells and finding immature and adult mites therein. The hive (colony) may be treated with various chemicals that cause the mites to drop off combs and bees. Sticky boards on the bottom of the colony can be used to examine hive debris and mites. Alternatively the “bump test” can be used for rapid screening. Definitive diagnosis at the laboratory is based on morphological examination under a microscope. Confirmatory testing can be done by conventional polymerase chain reaction and sequencing.