The stock structure of grey mackerel Scomberomorus semifasciatus in Australia as inferred from its parasite fauna

The scombrid Scomberomorus semifasciatus is an important component of inshore fisheries in tropical Australia. Data on the parasite fauna of 593 fish from areas off northern and eastern Australia were examined for evidence of discrete fish populations. The parasites used were juveniles of Pterobothrium pearsoni, Callitetrarhynchus gracilis, Anisakis simplex (sensu latu) and Terranova sp. Tukey Kramer pairwise comparisons gave significant differences in the abundances of two or more parasites between fish from the east coast, the eastern Gulf of Carpentaria and the remainder of northern Australia. Multivariate analysis gave further evidence of differences and the results suggest that at least 4 populations or stocks of grey mackerel occur along the northern and eastern coastline of Australia.

Characterization of the antibody response in birds following infection with wild-type and attenuated strains of Eimeria tenella and Eimeria necatrix.

Live vaccines containing attenuated parasite strains are increasingly used to control chicken coccidiosis. In this paper antibody responses elicited by infections with wild-type and attenuated strains of Eimeria tenella and E.necatrix were characterized by immunoblotting and ELISA with homologous and heterologous antisera. Few differences between antisera from birds infected with wild and attenuated strains of E. tenella were evident in immunoblots conducted with merozoite antigen preparations from both E. tenella strains, however the reactivity of sera raised in birds infected with the wild-type strain was noticeably more intense. In ELISAs conducted with merozoite antigen preparations, antisera from birds infected with the wild-type strains of E. tenella and E. necatrix consistently produced a significantly higher (P < 0.05) antibody response than antisera from birds infected with the attenuated strains. Likewise, avidity ELISAs conducted with the E. tenella strains demonstrated that antibodies in birds infected with the wild-type strain were of significantly higher avidity (P < 0.05) than antibodies in birds infected with the attenuated strain. The differences in the antibody responses are probably due to changes in the attenuated strain as a result of selection for precocious development and the less severe tissue damage and inflammation of the intestine resulting from infection with the attenuated strain.

Freeze-drying of ovalbumin loaded mesoporous silica nanoparticle vaccine formulation increases antigen stability under ambient conditions

Amino functionalised mesoporous silica nanoparticles (AM-41) have been identified as a promising vaccine delivery material. The capacity of AM-41 to stabilise vaccine components at ambient temperature (23–27 °C) was determined by adsorbing the model antigen ovalbumin (OVA) to AM-41 particles (OVA-41). The OVA-41 was successfully freeze-dried using the excipients 5% trehalose and 1% PEG8000. Both the immunological activity of OVA and the nanoparticle structure were maintained following two months storage at ambient temperature. The results of immunisation studies in mice with reconstituted OVA-41 demonstrated the induction of humoral and cell-meditated immune responses. The capacity of AM-41 particles to facilitate ambient storage of vaccine components without loss of immunological potency will underpin the further development of this promising vaccine delivery platform.