Assessment of virally vectored autoimmunity as a biocontrol strategy for cane toads.

Background: The cane toad, Bufo (Chaunus) marinus, is one of the most notorious vertebrate pests introduced into Australia over the last 200 years and, so far, efforts to identify a naturally occurring B. marinus-specific pathogen for use as a biological control agent have been unsuccessful. We explored an alternative approach that entailed genetically modifying a pathogen with broad host specificity so that it no longer caused disease, but carried a gene to disrupt the cane toad life cycle in a species specific manner.

Cane toad toxicity: an assessment of extracts from early developmental stages and adult tissues using MDCK cell culture.

Extracts of the cane toad (Bufo [Chaunus] marinus) adversely affected the growth of Mardin-Darby canine kidney (MDCK) cells during culture. In a similar manner to ouabain treatment, application of toad extracts over a 24 h period resulted in high levels of cytotoxicity, as indicated by cell detachment, increased membrane permeability and loss of mitochondrial function. Cell viability and growth were unchanged for controls (PBS) and increased with the application of Limnodynastes peronii tadpole and adult frog extracts.

Corticosteroid treatment does not reactivate canine herpesvirus in red foxes.

To study canine herpesvirus (CHV) reactivation from red foxes (Vulpes vulpes), 29 foxes with varying CHV antibody and CHV carrier status were treated with methylprednisolone acetate, a glucocorticosteroid drug with prolonged immunosuppressive effect in dogs. In the first experiment, 17 foxes with unknown CHV carrier status were treated once with methylprednisolone: in the second experiment, five foxes were treated twice, 4 mo after being intravenously CHV infected; and in the third experiment, six foxes were treated five times, 11 mo after peroral CHV infection. Infectious CHV was not isolated after treatment from either naturally or experimentally CHV-infected foxes or from untreated, CHV-seronegative in-contact foxes.