Amoeba (Malpighamoeba mellificae) is a protozoan amoeba-like parasite found in the gut of adult bees that causes encysts in the malpighian tubules - excretory organs, long, threadlike projections originating at the junction of the mid-gut and the hind-gut which act as the bees kidneys. Massive lethal invasions of bees are not frequent and the anatomical protective barriers of the gut limit the destructive action of the parasite. It is not considered a cause colony mortality. The diagnosis of the disease can only be done microscopically, but an apparent inability of healthy-looking colonies to build up may indicate infection.
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Image Courtesy The Animal and Plant Health Agency (APHA), Crown Copyright
Nosema apis and Amoeba
The cysts found in the malpighian tubules can only be detected using a compound microscope. The Amoebiasis symptoms are more common in spring and are similar to Nosemosis and often occur together, colony collapse, crawling bees outside the hive unable to fly, diarrhoea - watery faeces of yellowish coloration. There is no known medical treatment against Amoebiasis. Suspect colonies should have samples taken and sent off to SASA in a paper bag for analysis.
Life Cycle - The life of the cysts in the honeycombs is of 6 months in faeces.
Hive Examination - Examination of hives, components and debris is required especially in spring. Abnormalities such as the signs of dysentery, crawling and dead bees are easily spotted.
Monitoring - Vigilance is important with all honeybee diseases. Check all apiaries and colonies regularly for health and suspect any colonies that are not thriving where there is no already known reason. Colonies that die out should be examined thoroughly and sealed to prevent robbing and spread of any disease present.
Presently there is no effective medical treatment for Amoebiasis. Disinfection with acetic acid of the honeycombs destroys the cysts of Amoebiasis and the spores of Nosemosis. The disease has only slight effect on healthy colonies but may have a more serious effect on weakened colonies. Prevention is the best method of controlling this disease by maintaining healthy, strong and vigorous colonies that display good hygienic traits. Good husbandry contributes greatly to overall colony behaviour and health, thereby avoiding the conditions in which disease can flourish. Colonies that suffer excessively from Amoebiasis may need to be re-queened. Some strains of bee are also more prone to infestations than others. Disease prevention is best practice, maintain good apiary housekeeping:
Amoeba can exist in beekeeping equipment, honey, wax, etc. and can spread during normal hive / colony manipulations.