Aerial poisoning of the landscape
Aerial poisoning of the landscape, called “possum control”, and testing and slaughtering of infected livestock were used together to control Tb. Widespread poisoning occurred even if there was only a suspected infection in wildlife.
| 1991 | Davidson, M. | Surveillance 18(5) | Tuberculosis in possums | “During this period sampling of possum populations throughout the Buller area showed that infection (with Tb) was wide-spread in that species. In 1969 an infected possum had been found in the Wairarapa, an area in which recurring infection in some cattle herds had been observed. The pressure was then on for some action to be taken. MAF efforts were directed at what was necessarily an empirical approach, decimation of possum populations, based on the hypotheses of the time. The first such large-scale operations were carried out in Buller county in 1972, followed a few months later by the first campaign in the Wairarapa. It is probably worth noting that, in essence, this remains the basic method of dealing with the problem.” |
| 2015 | Livingstone, P.G., Hancox, N., Nugent, G. & de Lisle, G.W. | NZ Veterinary Journal 63 (Supp 1):4-18 | Toward eradication: the effect of Mycobacterium bovis infection in wildlife on the evolution and future direction of bovine tuberculosis management in New Zealand | “wide-scale possum control programmes were initiated in 1972…In those areas where isolated pockets of possums with TB were identified, intensive control was usually undertaken over the whole site…Possum control, combined with TB testing of beef and dairy herds, resulted in a halving of reactor rates (the term widely used in New Zealand for the proportion of tested animals with a positive skin-test reaction), from 33.7 per 10,000 cattle tested in the 1975/76 financial year to 14.1 per 10,000 in 1980/81” |
| 1994 | Tweddle, N.E. & Livingstone, P. | Veterinary Microbiology 40 (1994) 23-39 | Bovine tuberculosis control and eradication programs in Australia and New Zealand | “The central component to managing TB in cattle herds in Endemic areas in the 1970s, in addition to a test and slaughter policy, was mass poisoning of possums using sodium monofluoroactate (1080) poison.” |
| 2015 | Livingstone, P.G., Hancox, N., Nugent, G. & de Lisle, G.W. | NZ Veterinary Journal 63 (Supp 1):4-18 | Toward eradication: the effect of Mycobacterium bovis infection in wildlife on the evolution and future direction of bovine tuberculosis management in New Zealand | “Similar reductions in reactor rates and herd infection levels were observed throughout the rest of the Buller district following possum control (Davidson, 1976). Although not formally confirmed until much later, this provided compelling evidence that TB in possums had become a major source of spillback infection for cattle.” |
| 2016 | Nugent, G. | Kararehe Kino 27:16-17 | The main host of TB is … possum! | “Within a decade of TB being found to be common in some local populations of possums, possum control was applied near and on farms in which the level of TB in cattle had stayed stubbornly high despite intensive quarterly testing and culling of infected animals. Within two years of such possum control, TB in cattle had dropped to very low levels (Fig.), strongly implying that possum control had largely stopped TB transmission from possums to cattle. This pattern and response to control was also observed in other places in the 1980s, leaving no need for further scientific confirmation.” |
| 2000 | Montague, T.L. | In T.L. Montague (Ed.) The brushtail possum: biology, impact and management. Manaaki Whenua Press. | Editor’s Conclusion – the beginning of the end or the end of the beginning. In The Brushtail Possum Biology, Impact and Management of an Introduced Marsupial | “The unique and perverse nature of bovine tuberculosis (Tb) in New Zealand has also made it difficult to show clear benefits of poisoning possums when seeking to reduce the incidence of Tb in livestock…examples are needed as unfortunately Hohotaka…is the only documented example with an experimental control, and most scientists will not be willing to generalise from one example. No doubt more evidence will accumulate with time.” |
| 2000 | Coleman, J., Caley, P. | pp 92-104. In Montague, T.L. (Ed.) The Brushtail Possum. Biology, impact and management if an introduced marsupial. Montague, T.L. (Ed.) Manaaki Whenua Press, Lincoln, New Zealand. 292 pp. | Possums as a reservoir of bovine Tb | “Tuberculosis foci in possum populations may be long-lasting. Ongoing studies in Westland have recorded infection at the same or nearby trap sites on bush/pasture margins apparently persisting for 16 (Cooke et al. 1995) and 25 years (Coleman & Caley unpubl. data). Such infections frequently persist despite possum control, presumably either through more frequent horizontal transmission in favoured longstanding den sites or through their contamination, although neither is proven.” |
| 1994 | Tweddle, N.E. & Livingstone, P. | Veterinary Microbiology 40 (1994) 23-39 | Bovine tuberculosis control and eradication programs in Australia and New Zealand | “Properties in Surveillance areas which either had an unexplained herd infection, or an animal in the herd that was spreading TB, also receive possum control.” |
| 2015 | Livingstone, P.G., Hancox, N., Nugent, G. & de Lisle, G.W. | NZ Veterinary Journal 63 (Supp 1):4-18 | Toward eradication: the effect of Mycobacterium bovis infection in wildlife on the evolution and future direction of bovine tuberculosis management in New Zealand | “A VRA was defined as a geographical area in which TB had either been identified in a wildlife maintenance host (possums), or was strongly suspected to be present in a wildlife maintenance host based on epidemiological findings from infected cattle and deer herds.” |