Biological control of the rabbit in Australia: lessons not learned?

The story of the spread of the European rabbit across Australia, and of the two viruses used to control it, is an interesting way to look at some of the issues associated with biological control. What can be learned from the way this system developed, and what has been learned, or not learned, from the mistakes made? Here, we look at these events and examine what insights can be gained from this history.

Body size and ovarian cancer: case-control study and systematic review (Australia)

Objective: Although increased body mass is an established risk factor for a variety of cancers, its relation with cancer of the ovary is unclear. We therefore investigated the association between measures of body mass index (BMI) and ovarian cancer risk. Methods: Data from an Australian case-control study of 775 ovarian cancer cases and 846 controls were used to examine the association with BMI. We have also summarized the results from a number of other studies that have examined this association. Results: There was a significant increased risk of ovarian cancer with increasing BMI, with women in the top 15% of the BMI range having an odds ratio (OR) of 1.9 (95% confidence interval (CI), 1.3-2.6) compared with those in the middle 30%. Stratifying by physical activity showed a stronger effect among inactive women (OR = 3.0, 95% CI 1.3-6.9). The overall effect was consistent with the findings of most prior population-based case-control studies, while cohort studies reported positive effects closer to the null. Hospital-based studies gave variable results. Conclusions: Taken together, the evidence is in favor of a small to moderate positive relation between high BMI and occurrence of ovarian cancer.

Opportunities for the control of coronary heart disease in Australia

Objective: To estimate the number of coronary events that could be prevented in Australia each year by the use of preventive and therapeutic strategies targeted to subgroups of the population based on their levels of risk and need. Methods: Estimates of risk reduction from the published literature, prevalence estimates of elevated risk factor levels from the 1995 National Health Survey and treatment levels from the Australian collaborating centres in the World Health Organization's MONICA Project were used to calculate numbers of coronary events preventable among men and women aged 35-79 years in Australia. Results: Approximately 14,000 coronary events could be avoided each year if the mean level of cholesterol in the population was reduced by 0.5 mmol/L, smoking prevalence was halved and prevalence of physical inactivity was reduced to 25%. This represents a reduction in coronary events of about 40%. Even with less optimistic targets, a reduction of 20% could be attained, while the achievement of some internationally recommended targets could lead to almost 50% reduction. In the short term, aggressive medical treatment of people with elevated levels of risk factors and established coronary disease offers the greatest opportunity for reducing coronary events. Conclusion: A comprehensive approach to reduce levels of behavioural and biological risk factors and improve the use of effective treatment could lead to a large reduction in coronary event rates. In the long term, primary prevention - especially to reduce smoking, lower cholesterol levels and increase exercise - has the potential to reduce the population levels of risk and hence contain the national cost of coronary disease.

Melanoma in adolescents: A case-control study of risk factors in Queensland, Australia

The incidence of melanoma increases markedly in the second decade of life but almost nothing is known of the causes of melanoma in this age group. We report on the first population-based case-control study of risk factors for melanoma in adolescents (15-19 years). Data were collected through personal interviews with cases, controls and parents. A single examiner conducted full-body nevus counts and blood samples were collected from cases for analysis of the CDKN2A melanoma predisposition gene. A total of 201 (80%) of the 250 adolescents with melanoma diagnosed between 1987 and 1994 and registered with the Queensland Cancer Registry and 205 (79%) of 258 age-, gender- and location-matched controls who were contacted agreed to participate. The strongest risk factor associated with melanoma in adolescents in a multivariate model was the presence of more than 100 nevi 2 mm or more in diameter (odds ratio [OR] = 46.5, 95% confidence interval [Cl] = 11.4-190.8). Other risk factors were red hair (OR = 5.4, 95%Cl = 1.0-28.4); blue eyes (OR = 4.5, 95%Cl = 1.5- 13.6); inability to tan after prolonged sun exposure (OR = 4.7, 95%Cl = 0.9-24.6); heavy facial freckling (OR = 3.2, 95% Cl = 0.9-12.3); and family history of melanoma (OR = 4.0, 95%Cl = 0.8-18.9). Only 2 of 147 cases tested had germline variants or mutations in CDKN2A. There was no association with sunscreen use overall, however, never/rare use of sunscreen at home under the age of 5 years was associated with increased risk (OR = 2.2, 95%Cl = 0.7-7.1). There was no difference between cases and controls in cumulative sun exposure in this high-exposure environment. Factors indicating genetic susceptibility to melanoma, in particular, the propensity to develop nevi and freckles, red hair, blue eyes, inability to tan and a family history of the disease are the primary determinants of melanoma among adolescents in this high solar radiation environment. Lack of association with reported sun exposure is consistent with the high genetic susceptibility in this group. (C) 2002 Wiley-Liss, Inc.

Point source inoculation of Mesocyclops (Copepoda : Cyclopidae) gives widespread control of Ochlerotatus and Aedes (Diptera : Culicidae) immatures in service manholes and pits in North Queensland, Australia

This study details the novel application of predacious copepods, genus Mesocyclops, for control of Ochlerotatus tremulus (Theobald) group and Aedes aegypti (L.) mosquito larvae in subterranean habitats in north Queensland, Australia. During June 1997, 50 Mesocyclops sp. I were inoculated into one service manhole in South Townsville. Wet season rainfall and flooding in both 1998 and 2000 was responsible for the dispersal of copepods via the underground pipe system to 29 of 35 manholes over an area of 1.33 km(2). Significant reductions in Aedes and Ochlerotatus larvae ensued. In these habitats, Mesocyclops and Metacyclops were able to survive dry periods, when substrate moisture content ranged from 13.8 to 79.9%. At the semiarid inland towns of Hughenden and Richmond, cracking clay soil prevents drainage of water from shallow service pits where Oc. tremulus immatures numbered from 292-18,460 per pit. Introduction of Mesocyclops copepods into these sites during May 1999 resulted in 100% control of Oc. tremulus for 18 mo. One uninoculated pit subsequently became positive for Mesocyclops with resultant control of mosquito larvae.

Farm exposures, parental occupation, and risk of Ewing's sarcoma in Australia: a national case-control study

Objective: It has been suggested that parental occupation, particularly farming, increased the risk of Ewing's sarcoma in the offspring. In a national case-control study we examined the relationship between farm and other parental occupational exposures and the risk of cancer in the offspring. Methods: Cases were 106 persons with confirmed Ewing's sarcoma or peripheral primitive neuroectodermal tumor. Population-based controls (344) were selected randomly via telephone. Information was collected by interview (84% face-to-face). Results: We found an excess of case mothers who worked on farms at conception and/or pregnancy (odds ratio (OR) = 2.3, 95% confidence interval (CI) 0.5-12.0) and a slightly smaller excess of farming fathers; more case mothers usually worked as laborers, machine operators, or drivers (OR = 1.8, 95% CI 0.9-3.9). Risk doubled for those whose mothers handled pesticides and insecticides, or fathers who handled solvents and glues, and oils and greases. Further, more cases lived on farms (OR = 1.6, 95% CI 0.9-2.8). In the 0-20 years group, the risk doubled for those who ever lived on a farm (OR = 2.0, 95% CI 1.0-3.9), and more than tripled for those with farming fathers at conception and/or pregnancy (OR = 3.5, 95% CI 1.0-11.9). Conclusions: Our data support the general hypothesis of an association of Ewing's sarcoma family of tumors with farming, particularly at younger ages, who represent the bulk of cases, and are more likely to share etiologic factors.

THE ORGANISATION OF RABBIT CONTROL (Oryctolagus cuniculus) IN WESTERN AUSTRALIA

ABSTRACT: Under Western Australian legislation, landholders have an obligation to control rabbits on their properties; local authorities the responsibility to supervise their work whilst the Agriculture Protection Board has a Statewide supervisory and co-ordination role. Prior to 1950 (when the Agriculture Protection Board was formed) the central role was in the hands of a Government department which, through lack of staff and money was unable to provide adequate supervision, and rabbits were in plague proportions. Since 1950, the Board has actively engaged in a vigorous policy aimed at tighter control and supervision. To enable this, the Board has entered into a voluntary scheme with local authorities whereby the role of local supervision of landholders is passed to staff employed by the Board, but jointly financed by the local authority and the Board. A contract poisoning service is also pro¬vided by the Agriculture Protection Board to any landholder who is unable or unwilling, to meet his obligations in this area. Both services are subsidised. Two of the major reasons for the poor level of control existing before 1950, have thereby been minimised. Soon after its formation, the Board set up a research section which has devoted nearly all of its activities to applied research on control of the State's many vertebrate pest problems. In the rabbit control area, poisoning has received most attention. The "One-Shot" method of poisoning was developed after years of research. Fumigation is at present being closely studied as is the economics of complete eradication from some areas of the State. Greatest needs in the applied rabbit research field at present are: (1) a selective poison, or poisoning regime, which will not harm stock, and (2) a more complete understanding of the economics of control and eradication. The serious rabbit problem which existed in 1950 has been reduced to very small proportions, by organisational development using local research findings. These organisational developments have been implemented by circumvention rather than confrontation.

Direct support and general support maintenance manual : tank, combat, full-tracked, 105-MM gun, M1 (2350-01-061-2445) General Abrams : sighting and fire control.

Description based on vol. I, pt. 2.

Intermediate direct support and intermediate general support maintenance manual : tank, combat, full-tracked, 105-MM gun, M1 (2350-01-061-2445) and tank, combat, full-tracked, 105-MM gun, IPM1 (2350-01-136-8738) and tank, combat, full-tracked, 120-MM gun, M1A1 (2350-01-087-1095) : General Abrams : sighting and fire control.

"September 1987"--Vol. 1.

Intermediate direct support and intermediate general support maintenance manual : tank, combat, full-tracked, 105-mm gun, M1 (2350-01-061-2445) and tank, combat, full-tracked, 105-mm gun, IPM1 (2350-01-136-8738) and tank, combat, full-tracked, 120-mm gun, M1A1 (2350-01-087-1095) : General Abrams : sighting and fire control.

"9 July 1990"--Vol. 2, change no. 5.

A national case-control study of Ewing's sarcoma family of tumours in Australia

Limited population-based epidemiologic information is available on Ewing's sarcoma family of tumours (ESFT), a rare group of neoplasms. Several associations have been noted on a few studies but results were not consistent, except for exposure to farming among cases and their parents. Here we present the non-farm findings of a nationwide case-control study of ESFT in children and young adults in Australia. The analysis included 106 persons with confirmed ESFT and 344 population-based controls selected randomly via telephone. Information was collected by interview (84% face to face). We found a strong and significant association of ESFT with hernias, in particular hernia repaired in hospital (OR = 5.6, 95% Cl 1.3-6.4). Among other factors, there was a near doubling of risk for males, and male cases had their pubertal signs earlier (started shaving earlier) than male controls. There was also an increased risk of ESFT at higher levels of self-assessed exercise, but no other factor really stood out. For pregnancy-related factors, there was a tripling of risk for glandular fever, a doubling of risk for urinary tract infection and a near doubling of risk for X-rays during or just before pregnancy, but these estimates were not significant. In addition, there was a large number of inverse associations with medical conditions (specifically bone disorders), case exposure to medications, vaccinations and X-rays, with ultrasound during the pregnancy having the most certain effects. We conclude that, although the aetiology of ESFT remains obscure, overall there is strong evidence of an association with inguinal hernia; this can now be added to the farm-associated risk reported by others and us. The other associations reported here await replication and refinement in future studies. (C) 2003 Wiley-Liss, Inc.

Hospital-based case-control study of bronchiectasis in indigenous children in central Australia

Background: Childhood pneumonia has been reported to be associated with the development of bronchiectasis but there are no case-control studies that have examined this. This study examined the relationship between hospital admission for episode(s) of pneumonia and the risk of radiologically proven bronchiectasis. Methods: A medical record-based case-control study of bronchiectasis in Indigenous children was conducted in Central Australia. Controls (183), matched to cases (61) by gender, age and year of diagnosis, were Indigenous children hospitalized with other conditions. Results: There was a strong association between a history of hospitalized pneumonia and bronchiectasis [odds ratio (OR), 15.2; 95% confidence interval (95% CI) 4.4-52.7]. This was particularly evident in recurrent hospitalized pneumonia (P for trend < 0.01), severe pneumonia episodes with longer hospital stay (P for trend < 0.01), presence of atelectasis (OR 11.9; 95% CI 3.1-45.9) and requirement for oxygen (P for trend < 0.01). The overall number of pneumonia episodes, rather than its site, was associated with bronchiectasis. Although the total number of pneumonia episodes in the first year of life did not increase the risk of bronchiectasis, more severe episodes early in life did. Malnutrition, premature birth and being small for gestational age were more common findings among cases. Breast-feeding appeared to be a protective factor (OR 0.2; 95% CI 0.1-0.7). Conclusions: Although we cannot fully answer the question of why bronchiectasis is much more common in Indigenous children, we have provided strong evidence of an association between bronchiectasis and severe and recurrent pneumonia episodes in infancy and childhood.