• abalone viral ganglioneuritis;
  • haemocyte counts;
  • Haliotis laevigata

Objective  To compare microscopic lesion severity with circulating total haemocyte counts (THC) in abalone affected by abalone viral ganglioneuritis (AVG).

Results  A herpes-like virus led to severe mortality in a number of Australian abalone farms in 2006. The infection was associated with severe necrotising ganglioneuritis. The microscopic lesions were well demarcated, affecting the neural tissue almost exclusively and were characterised by necrosis and increased cellularity in affected ganglia and nerves. On two farms, the presence or absence of typical AVG pathology was compared with THC. Those abalone with microscopic lesions of AVG had significantly lower haemocyte counts. The mean THC in abalone with no evidence of AVG from both farms was 4.6 × 106/mL (±0.3 SE). The THC in AVG-affected abalone in farm 1 was 2.8 × 106/mL (±0.5 SE) and farm 2 was 0.98 × 106/mL (±0.4 SE).

Conclusions  Severe AVG is associated with leucopenia in affected abalone.