Development of a semi-quantitative scoring protocol for gill lesion assessment in greenlip abalone Haliotis laevigata held at elevated water temperature.

Water temperatures that exceed thermal optimal ranges (~19 to 22°C for greenlip abalone Haliotis laevigata, depending on stock genetics) can be associated with abalone mortalities. We assessed histopathological changes in H. laevigata gills held in control (22°C) or elevated (25°C) water temperature conditions for 47 d by developing a new scoring protocol that incorporates histopathological descriptions and relative score summary. Lesions were allocated to 1 of 3 reaction patterns, (1) epithelial, (2) circulatory or (3) inflammatory, and scored based on their prevalence in gill leaflets. Indices for each reaction pattern were calculated and combined to provide an overall gill index. H. laevigata held in 25°C water temperature had significantly more epithelial lifting and hemolymph channel enlargement and significantly higher gill and circulatory reaction pattern indices than H. laevigata held in 22°C water temperature. One H. laevigata had a proliferation of unidentified cells in the v-shaped skeletal rod of a gill leaflet. The unidentified cells contained enlarged nuclei, a greater nucleus:cytoplasm ratio and, in some cases, mitotic figures. This cell population could represent a region of hematopoiesis in response to hemocyte loss or migration to a lesion. Without thorough diagnostic testing, the origin of these larger cells cannot be confirmed. The new scoring protocol developed will allow the standard quantification of gill lesions for H. laevigata, specifically for heat-related conditions, and could further be adapted for other Haliotis spp.

Detection of infectious spleen and kidney necrosis virus (ISKNV) and turbot reddish body iridovirus (TRBIV) from archival ornamental fish samples.

Although infections caused by megalocytiviruses have been reported from a wide range of finfish species for several decades, molecular characterisation of the viruses involved has been undertaken only on more recent cases. Sequence analysis of the major capsid protein and adenosine triphosphatase genes is reported here from formalin-fixed, paraffin-embedded material from 2 archival ornamental fish cases from 1986 and 1988 in conjunction with data for a range of genes from fresh frozen tissues from 5 cases obtained from 1991 through to 2010. Turbot reddish body iridovirus (TRBIV) genotype megalocytiviruses, previously not documented in ornamental fish, were detected in samples from 1986, 1988 and 1991. In contrast, megalocytiviruses from 1996 onwards, including those characterised from 2002, 2006 and 2010 in this study, were almost indistinguishable from infectious spleen and kidney necrosis virus (ISKNV). Three of the species infected with TRBIV-like megalocytiviruses from 1986 to 1991, viz. dwarf gourami Trichogaster lalius (formerly Colisa lalia), freshwater angelfish Pterophyllum scalare and oscar Astronotus ocellatus, were infected with ISKNV genotype megalocytiviruses from 2002 to 2010. The detection of a TRBIV genotype isolate in ornamental fish from 1986 represents the index case, confirmed by molecular sequence data, for the genus Megalocytivirus.

An egg drop associated with splenomegaly in broiler breeders.

A new disease in broiler breeders known in Australia as Big Liver and Spleen Disease (BLS) is described from field observations, retrospective record analysis, and detailed study of a selected flock. BLS has a predilection for adult birds. It is characterized clinically by a sudden drop in egg production, splenomegaly, hepatomegaly, and increased mortality and histologically by a period of lymphoproliferation followed by a period of lymphoid destruction that coincides with the clinical signs. Epidemiology suggests an infectious cause, though initial attempts at isolation of a causative agent have been unsuccessful, and it is serologically distinct from the common avian viral and mycoplasma diseases.

Intestinal mast cell changes in guinea pigs infected with the nematode Trichostrongylus colubriformis.

Infection of guinea pigs with the parasitic nematode Trichostrongylus colubriformis was followed by a three- to fourfold increase in the number of mast cells in the small intestine mucosa. Mitotic figures were observed in many mast cells during the period numbers were increasing. Many mast cells developed cytoplasmic granules which, unlike pre-infection mast cell granules, contained crystalline structures.