The pathogenicity of Bacillus thuringiensis ssp. kurstaki to gamma-irradiated Cadra cautella (Walker) (Lepidoptera: Phycitidae)

The effects of radioactive pollution on the dynamics of infectious diseases in wildlife

The interactions between infectious diseases and chemical pollution are well known and recognised as important factors in regulating the way wild animals respond to contaminant exposure. However, the impact of ionising radiation and radionuclides has often been overlooked when assessing host-pathogen interactions in polluted habitats, despite often occurring together with chemical contamination. Nevertheless, a comprehensive body of literature exists from laboratory and field studies on host-pathogen relationships under radiation exposure, and with a renewed interest in radioecology developing; an evaluation of infectious disease dynamics under these conditions would be timely. The present study assesses the impact of external ionising radiation and radionuclides on animal hosts and pathogens (viruses, bacteria, protozoans, helminths, arthropods) in laboratory studies and collates the data from field studies, including the large number of investigations undertaken after the Chernobyl accident. It is apparent that radiation exposure has substantial effects on host-pathogen relationships. Although damage to the host immune system is a major factor other variables, such as damage to host tissue barriers and inhibition of pathogen viability are also important in affecting the prevalence and intensity of parasitic diseases. Field studies indicate that the occurrence of host-pathogen associations in radioactively contaminated sites is complex with a variety of biotic and abiotic factors influencing both pathogen and host(s), resulting in changes to the dynamics of infectious diseases.

Effect of gamma-irradiation on the biology and ultrastructure of haemocytes of greater wax moth, Galleria mellonella (L.) (Lepidoptera: Galleridae)

This study was carried out on fully grown pupae of greater wax moth, Galleria mellonella L., gamma-irradiated to 100, 150, 300 and 400Gy. The four doses given to male parents in the F(1) generation decreased the average number of eggs per mated female, the percentage of egg hatching and the percentage of mating in both the male and female lines; the effects increased with the dose. Dose dependence of the reduction in the fecundity and the percentage of egg hatching among the female line pairings (female descendants of irradiated parental male pupae) was more significant than among the male line pairings (male descendants of irradiated parental male pupae). We also examined morphological changes in the irradiated blood cells using transmission electron microscopy (TEM). Vacuolization of the cytoplasm, disorganization and swelling of mitochondria were found.