Very little is known about how Tb is transmitted between animals in New Zealand.
Because of this the control plan being used by TbFree is based on assumptions, which are proving to be wrong.
2015 | Nugent, G., Buddle, B.M. & Knowles, G. | NZ Veterinary Journal 63 (Supp 1): 28-41 | Epidemiology and control of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula), in the primary wildlife host of bovine tuberculosis in New Zealand | “The dearth of robust empirical data on the epidemiological dynamics of TB in possums has led to the development of a plethora of mathematical and simulation models” |
2015 | Nugent, G., Buddle, B.M. & Knowles, G. | NZ Veterinary Journal 63 (Supp 1): 28-41 | Epidemiology and control of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula), in the primary wildlife host of bovine tuberculosis in New Zealand | “The current mainstream epidemiological model for possum TB…assumes, unrealistically, that possums become infectious to other possums from the moment of initial infection up until death.” |
2015 | Rouco, C. | Kararehe Kino 26:Aug | Estimating TB transmission rates among possums in the wild | “These results have two key implications for the team’s understanding of TB dynamics in possum populations. Firstly, transmission is highly variable across both space and time. Hence, understanding the conditions that lead to high rates of transmission could potentially allow the better targeting of control efforts for TB management. Secondly, the generally low rate of transmission observed suggests that 6 months may have been insufficient to document all of the secondary cases that would have occurred. Indeed, infected possums have been documented surviving for many years, periodically relapsing with and then resolving clinical disease. Such dynamics are common for TB infection in other species (including humans), and their consideration may be important for understanding how TB persists in possum populations.” |
2016 | Cross, F., Yockney, I., Nugent, G., Whitford, J., Latham, M.C. | Kararehe Kino 27:8-9 | How does chronic TB affect possum movements? | “These results confirm that the assumptions in the current possum-TB spatial model (i.e. that infected possums present a more or less constant infection risk over their whole range for the duration of the disease course) is possibly too simplistic. We now need to complete more detailed analyses of the movement data from tuberculosis possums, to explore how big an effect this new understanding has in changing the patterns of disease predicted by the possum-TB model.” |
2016 | Tompkins, D., Holland, P. | Kararehe Kino 27:14-15 | Lesion resolution may contribute to TB persistence in the face of control | “Recent trials to directly measure the rate at which infected possums transmit TB to uninfected possums in free-living populations have raised more questions than they have answered. While TB transmission in possums was successfully experimentally induced and monitored, the rates at which it occurred were too low to account for TB persistence based on current understanding of the disease in possums.” |
2010 | Environmental Protection Authority | P 5 | Annual Report on the Aerial Use of 1080 for the year ended 31 December 2010 | “Eradication of TB from wildlife depends on sustained possum control to achieve low, even possum densities across large areas for long enough periods to break the cycle of possum-to-possum transmission.” |
1986 | Anon | Surveillance 13(3) | Possum research and cattle tuberculosis | “relative density estimates of the possum population in each zone were made using trap data and faecal pellet counts. This was done in order to determine the relationship between possum density and the prevalence of tb infection in possums. The assumption for such a relationship was based on a mathematical model which simulates the effects of a terminal disease (rabies) on a wild animal population (foxes).” |