-Polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) analysis and microscopy were used to test 307 adult bee and 37 honey samples collected in Australia for the presence of two microsporidia, Nosema ceranae and Nosema apis. N. ceranae was detected in samples from 4 states (Queensland, New South Wales, Victoria and South Australia) and was most commonly found in samples from Queensland where 28 (33.7%) of 83 samples were positive. New South Wales had the second highest prevalence with 15 (15.8%) of 95 samples positive. South Australia and Victoria had 4 (16%) of 25 and 2 (4.5%) of 44 samples positive respectively. N. ceranae was not detected in samples from Western Australia and Tasmania. N. apis was detected in samples from all states. Three honey samples (8.1%) were PCR positive for N. ceranae. These positive honey samples originated from beekeepers in Queensland. Six imported honey samples tested were negative for both Nosema spp.Nosema ceranae / Nosema apis / nosemosis / Apis mellifera / PCR / RFLP

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-A quantitative assay for the transmission of European foulbrood (EFB) in artificially raised larvae was developed. This assay was used to determine the concentration of oxytetracycline (OTC) required to prevent larvae from developing EFB and whether 8 fatty acids (undecanoic, lauric [dodecanoic], myristic, myristoleic, ricinoleic, ricinelaidic, homo-y-linolenic and 13,16,19-docosatrienoic acids) which had previously been demonstrated to inhibit the growth of Melissococcus plutonius cultures, could protect larvae from developing EFB. The larval assay involved grafting individual larva (less than 24 hours old) into a single well in a micro-titre plate. Each larva was fed 10 µL of basic larval diet (BLD) containing 500 000 M. plutonius organisms. After 3 days the larvae were also fed 60 000 Paenibacillus alvei spores (a common secondary invader associated with EFB) in 10 µL BLD. The combination of these two organisms was required to reliably produce symptoms typical of that seen in field cases of EFB. Most larvae infected using this protocol died from EFB. To determine the efficacy of OTC, EFB infected larvae were fed 0, 1, 2.5, 5 10 or 20 µg/mL of OTC. Treatment with 1 µg/mL lowered the mortality rate from 93.75% to 69.5%. Treatments with 2.5 µg/mL to 10 µg/mL reduced the mortality rate further whereas treatment with 20 µg/mL reduced the rate to the same as the negative control. Larvae fed 20 or 200 µg/mL of each of the eight fatty acids were not protected from developing EFB.Melissococcus plutonius / European foulbrood treatment / oxytetracycline / Paenibacillus alvei / fatty acids