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AIM: To determine the effect of fertility control on the rate of transmission of bovine tuberculosis (Tb), caused by Mycobacterium bovis, in brushtail possums (Trichosurus vulpecula).METHODS: At two study sites with a history of Tb infection in the resident possum population, a sample of adult male and female possums (n=50), determined by palpation to be Tb-free, was surgically sterilised by gonadectomy. A sample of untreated Tb-free male and female possums (n=54) served as controls. Each study site was trapped every 2 months over a 3-year period, and the Tb status of the individuals in the trial assessed. At the conclusion of the trial, all remaining experimental individuals were killed, necropsied and examined for characteristic lesions typical of Tb. The rate of transmission of Tb infection was estimated using the incidence of tuberculous cases in the experimental animals and comparing it between sites, sex and sterilisation treatment.RESULTS: Sterilisation by gonadectomy resulted in a reduction in the rate of transmission of Tb in male possums by 53%, but a corresponding increase in sterilised females for reasons that are still unclear. However, this interaction was statistically weak (p=0.10). When the sexes were combined, there was no overall effect of sterilisation on the rate of transmission of Tb (p=0.43). Sterility treatment notwithstanding, there was a highly significant difference in the rate of transmission between the sexes (p=0.01), being almost one order of magnitude higher in untreated males compared with untreated females.CONCLUSIONS: Although lacking strong statistical support, these results suggest that fertility control that targets endocrine control of fertility may provide some additional benefits for disease control over that achieved by reductions in population density, by reducing the rate of transmission of M. bovis in male possums. However, additional studies are needed to confirm the validity of these results. The large difference in the rate of transmission of M. bovis in untreated males compared with untreated females suggests that transmission of Tb among males may be an important driver of the dynamics of Tb infection in possums.

AIM: To determine the trap-catch index (an estimate of abundance) of brushtail possum (Trichosurus vulpecula) populations infected with bovine tuberculosis (Tb; Mycobacterium bovis) that must be achieved, and the length of time such an index must be maintained, for Tb to be eliminated from possum populations and adjacent livestock.METHODS: Between 1997-1998 and 2000-2001, trap-catch surveys of possum populations naturally infected with Tb and subjected to population-control measures were undertaken at four forest sites and two farmland sites. At the same time, possum carcasses were collected at these sites and their Tb status determined, and all contiguous cattle and deer herds were Tb-tested and abattoir slaughter data for these herds were interrogated.RESULTS: Trap-catch surveys indicated that numbers of possums on the farmland sites surveyed were usually very low and well below the control targets set (i.e. a 5% trap catch or ∼0.5-1 possum/ha) for the study. In contrast, trap-catch surveys undertaken in forest sites indicated possum numbers were more variable, and often recovered rapidly from control operations to exceed control targets within 1-3 years. The annual rate of recovery of possum populations in half of the forest population surveys undertaken exceeded published intrinsic rates of increase for possums. The overall prevalence of Tb in possum populations was ≤1.9% at 5/6 sites, and was 6.5% at the sixth site. Juvenile possums infected with Tb were trapped within but near the edge of control zones and appeared to represent an immigrant source of infection. Mature infected possums survived control operations apparently by having home ranges in uncontrolled patches within control areas. Infection in possums appeared to be eliminated from one study site by the intensive control undertaken, but elimination at other sites appeared less likely. Levels of Tb in livestock on or adjacent to the study sites fell by at least 50% during the study, and cattle in one area tested clear for the first time in 20 years.CONCLUSIONS: Initial control of possums in forest appeared to achieve national control targets set by the Animal Health Board (AHB), despite trap-catch data often providing misleading population estimates. Such targets were often exceeded within 1-3 years. By comparison, possum control on farmland appeared to maintain populations at very low levels, while control on forest margins maintained populations at intermediate levels. Control was least effective in deep forest where human access was most difficult. Intensive population control measures appeared to have led to a reduced incidence of Tb in livestock at 3/4 sites, and elimination of Tb in livestock at one site. This result supports modelling studies that predict the eradication of Tb from possums through ongoing intensive control and may explain the lower success achieved with earlier less-intensive possum control.

Presents letters to the editor referencing topics and articles discussed in the previous issues of the journal "The Nation." Comments on the British policy towards Palestine; Discussion on the issues related to the Jewish-Arab community; Attitude of English soldiers towards Arabs.

The article presents the book "Father Knickerbocker Rebels," by Thomas Jefferson Wertenbaker. It is not revolutionary Paris that Wertenbaker is describing in the opening chapter of this exciting book, but colonial New York on the night of November 1, 1765, when the hated Stamp Act was to go into effect. At any rate, if not large-scale revolution, organized and often violent resistance to Great Britain's ever-increasing restrictions upon colonial trade led to the first emergence of the U.S. working-class, headed in New York by leftist merchants. The author gives a rounded story of the tense years of occupation; now New Yorkers need no longer know more about what went on in revolutionary New England than about the goings-on in their native city.

This article focuses on the book "World Communism Today," by Martin Ebon. It is a 536-page survey of the "hidden ways" of the Communists the world over, Ebon supplies needed light to those innocents who still believe that the Stalinist outfit is a group of persecuted idealists who have established some sort of workers' republic in the Soviet Union and are flow attempting, in the face of fierce capitalist opposition, to spread its manifest benefits to the workers of all the world, who have nothing to lose but their chains. It is too bad none of these innocents will read this well-documented book after they discover that its author is pretty hard-boiled about the "peculiar institution" which neo-communism has become.

The article discusses the book "Enjoyment of Living," by Max Eastman. Much of the book is devoted to a Freudian self-analysis, although he gives credit to a non-Freudian Maine doctor for curing the backaches, which perennially followed every frustrated love affair. Now he sees his many afflictions as psychosomatic.

Presents several letters to the editor. Comment on Trotskyism; Reasons for the failure of liberals, progressives and radicals in the election campaigns; Views on the Marx theory of labor; Publication of five hundred copies of a book dedicated to James Lardner, the last American volunteer of the Abraham Lincoln Brigade; Information on the book "The Revolution of Nihilism," by Herman Rauschning, the former National Socialist president of the Free City of Danzig.

Presents a letter to the editor about American socialism.