Avian influenza infection dynamics under variable climatic conditions, viral prevalence is rainfall driven in waterfowl from temperate, south-east Australia

Understanding Avian Influenza Virus (AIV) infection dynamics in wildlife is crucial because of possible virus spill over to livestock and humans. Studies from the northern hemisphere have suggested several ecological and environmental drivers of AIV prevalence in wild birds. To determine if the same drivers apply in the southern hemisphere, where more irregular environmental conditions prevail, we investigated AIV prevalence in ducks in relation to biotic and abiotic factors in south-eastern Australia. We sampled duck faeces for AIV and tested for an effect of bird numbers, rainfall anomaly, temperature anomaly and long-term ENSO (El-Niño Southern Oscillation) patterns on AIV prevalence. We demonstrate a positive long term effect of ENSO-related rainfall on AIV prevalence. We also found a more immediate response to rainfall where AIV prevalence was positively related to rainfall in the preceding 3-7 months. Additionally, for one duck species we found a positive relationship between their numbers and AIV prevalence, while prevalence was negatively or not affected by duck numbers in the remaining four species studied. In Australia largely non-seasonal rainfall patterns determine breeding opportunities and thereby influence bird numbers. Based on our findings we suggest that rainfall influences age structures within populations, producing an influx of immunologically naïve juveniles within the population, which may subsequently affect AIV infection dynamics. Our study suggests that drivers of AIV dynamics in the northern hemisphere do not have the same influence at our south-east Australian field site in the southern hemisphere due to more erratic climatological conditions.

The prevalence of glaucoma in the Melbourne Visual Impairment Project

PURPOSE: The purpose of the study was to determine the prevalence of glaucoma in Melbourne, Australia. METHODS: All subjects were participants in the Melbourne Visual Impairment Project (Melbourne VIP), a population-based prevalence study of eye disease that included residential and nursing home populations. Each participant underwent a standardized eye examination, which included a Humphrey Visual Field test, applanation tonometry, fundus examination including fundal photographs, and a medical history interview. Glaucoma status was determined by a masked assessment and consensus adjudication of visual fields, optic disc photographs, intraocular pressure, and glaucoma history. RESULTS: A total of 3271 persons (83% response rate) participated in the residential Melbourne VIP. The overall prevalence rate of definite primary open-angle glaucoma in the residential population was 1.7% (95% confidence limits = 1.21, 2.21). Of these, 50% had not been diagnosed previously. Only two persons (0.1%) had primary angle-closure glaucoma and six persons (0.2%) had secondary glaucoma. The prevalence of glaucoma increased steadily with age from 0.1% at ages 40 to 49 years to 9.7% in persons aged 80 to 89 years. There was no relationship with gender. The authors examined 403 (90.2% response rate) nursing home residents. The age standardized rate for this component was 2.36% (95% confidence limits = 0, 4.88). CONCLUSION: The rate of glaucoma in Melbourne rises significantly with age. With only half of patients being diagnosed, glaucoma is a major eye health problem and will become increasingly important as the population ages.

Prevalence of Myopia in adults: implications for refractive surgeons

BACKGROUND: We reviewed the research on the prevalence of myopia in the adult population to compare the refractive distribution of patients being treated with excimer laser photorefractive keratectomy to correct myopia, and assess the potential market for excimer laser surgery. METHODS: All published reports of myopia prevalence in adults were reviewed, as well as the prevalence in the Melbourne Visual Impairment Project and the distribution of refractive errors treated by the Melbourne Excimer Laser Group in 1994. RESULTS: A large population-based study of people aged 4 to 74 years in the U.S. showed that 43% had low myopia (less than -5.00 diopters (D)), 3.2% had high myopia (-5.01 to -10.00 D), and 0.2% had extreme myopia (more than -10.00 D). In Asian populations these proportions may be much higher and in African and Pacific island groups, much lower. In the Melbourne Visual Impairment Project, we found the prevalence of low myopia was 21%, high myopia 2%, and extreme myopia 0.3%. A single excimer laser has operated for 3 years in Melbourne. Of those treated, 45% had low myopia, 42% high myopia, and 13% extreme myopia. Compared to low myopes, high myopes were ten times (OR: 9.8; Confidence interval: 6.69 to 12.91) more likely to have excimer laser treatment and extreme myopes were 16 times (OR: 16.40; Confidence interval: 12.53 to 20.27) more likely. CONCLUSIONS: Although there are many more people with lower amounts of myopia in the population and the clinical results have been more predictable after one procedure in this group, the perceived benefits of excimer laser treatment may be greater for those with higher amounts of myopia, thus influencing their decision to undergo excimer laser surgery to correct their myopia. There is clearly a large market potential for excimer laser surgery in people with low myopia.

The fallacy of punishing offenders for the deeds of others: an argument for abolishing offence prevalence as a sentencing aggravating consideration

Sentencing outcomes are often marked by a considerable degree ofunpredictability. A key reason for this is the large number of aggravating andmitigating considerations, some of which have unstable questionablefoundation. This article argues that one well-established aggravating factor —offence prevalence — should be abolished. Pragmatically, the courts have notestablished workable criteria or a process for establishing whether an offence isprevalent. From a normative perspective, increasing the penalty for prevalentoffences is unsound because defendants should be punished for their acts, notthose of other offenders. Further, on close analysis, all of the rationales (in theform of general deterrence, denunciation and specific deterrence) invoked tojustify offence prevalence do not do so. Abolishing one sentencing variable willnot make sentencing a significantly more coherent or predictable discipline, butthe methodology applied in this article can be used to assess the viability ofother sentencing considerations.

The Counterweight Programme: prevalence of CVD risk factors by body mass index and impact of a 10% weight change

Objectives

To examine relationships between body mass index (BMI), prevalence of physician-recorded cardiovascular disease (CVD) risk factors in primary care, and changes in risk with 10% weight change.

Methods

The Counterweight Project conducted a baseline cross-sectional survey of medical records of 6150 obese (BMI ≥ 30 kg/m2), 1150 age- and sex-matched overweight (BMI 25 to <30 kg/m2), and 1150 age- and sex-matched normal weight (BMI 18.5 to <25 kg/m2) controls, in primary care. Data were collected for the previous 18 months to examine BMI and disease prevalence, and then modelled to show the potential effect of 10% weight loss or gain on risk.

Results

Obese patients develop more CVD risk factors than normal weight controls. BMI ≥ 40 kg/m2 exhibits increased prevalence of type 2 diabetes mellitus (DM), odds ratio (OR) men: 6.16 (p < 0.001); women: 7.82 (p < 0.001) and hypertension OR men: 5.51 (p < 0.001); women: 4.16 (p < 0.001). Dyslipidaemia peaked around BMI 35 to <37.5 kg/m2, OR men: 3.26 (p < 0.001); women 3.76 (p < 0.001) and CVD at BMI 37.5 to <40 kg/m2 in men, OR 4.48 (p < 0.001) and BMI ≥ 40 kg/m2 in women, OR 3.98 (p < 0.001).

A 10% weight loss from the sample mean of 32.5 kg/m2 reduced the OR for type 2 DM by 30% and CVD by 20%, while 10% weight gain increased type 2 DM risk by more than 35% and CVD by 20%.

Conclusion

Obesity plays a fundamental role in CVD risk, which is reduced with weight loss. Weight management intervention strategies should be a public health priority to reduce the burden of disease in the population.