Objective: To compare cancer incidence and survival for the Northern Territory (NT) Indigenous population with that of other Australians, and to assess NT Indigenous incidence time trends. Methods: Cancer registry data were used to calculate cancer incidence rate ratios (NT Indigenous to total Australian), the average annual change in NT Indigenous cancer incidence and the relative risk of cancer death after diagnosis of cancer (NT Indigenous to combined Western Australian and Tasmanian cases) for 1991–2001. Results: For NT Indigenous people, incidence rates were high for cancers of the liver, gallbladder, cervix, vulva and thyroid and, in younger people only, for cancers of the oropharynx, oesophagus, pancreas and lung, but low for cancers of the colon and rectum, breast, ovary, prostate, bladder, kidney, melanoma and lymphoma. Incidence rate ratios ranged from 0.1 for melanoma to 7.4 for liver cancer. Incidence increased for breast and pancreatic cancers. Survival was low for almost all specific cancers examined, and for all cancers combined (relative risk of death 1.9, 95% Cl 1.7‐2.1). Conclusions: Compared with other Australians, NT Indigenous people have higher, and increasing, incidence for some cancers (particularly smoking‐related cancers) and lower survival for most. Implications: Cancer has a greater impact on NT Indigenous people than other Australians. Well‐established cancer risk factors should be more effectively tackled in Indigenous people and known effective screening programs more effectively implemented. Research is urgently required into the reasons why survival from cancer in NT Indigenous people is so much lower than in other Australians.
Objective: To investigate whether Indigenous Australians with cancer have more advanced disease at diagnosis than other Australians, and whether late diagnosis explains lower Indigenous cancer survival rates. Design: Retrospective cohort study. Setting and participants: Indigenous and non‐Indigenous people diagnosed with cancers of the colon and rectum, lung, breast or cervix and non‐Hodgkin lymphoma in the Northern Territory of Australia in 1991–2000. Main outcome measures: SEER summary stage of cancer at diagnosis (local, regional or distant spread), cause‐specific cancer survival rates and relative risk of cancer death. Results: Diagnosis with advanced disease (regional or distant spread) was more common for Indigenous people (70%; 95% CI, 62%–78%) than for non‐Indigenous people (51%; 95% CI, 53%–59%) with cancers of the colon and rectum, breast, cervix and non‐Hodgkin lymphoma, but for lung cancer the opposite was found (Indigenous, 56% [95% CI, 46%–65%] v non‐Indigenous, 69% [95% CI, 64%–75%]). Stage‐adjusted survival rates were lower for Indigenous people for each cancer site. With few exceptions, the relative risk of cancer death was higher for Indigenous people for each category of stage at diagnosis for each cancer site. Conclusions: Health services apparently could, and should, be performing better for Indigenous people with cancer in the Northern Territory, and probably elsewhere in Australia. This study has demonstrated that data from cancer registers, enhanced with data on stage at diagnosis, can be used to monitor health service performance for Indigenous Australians in the Northern Territory; similar data is available in other States, and could be used to monitor health service performance for Indigenous people throughout Australia.
Echinococcosis, resulting from infection with tapeworms Echinococcus granulosus and E. multilocularis, has a global distribution with 2-3 million people affected and 200,000 new cases diagnosed annually. Costs of treatment for humans and economic losses to the livestock industry have been estimated to exceed $2 billion. These figures are likely to be an underestimation given the challenges with its early detection and the lack of mandatory official reporting policies in most countries. Despite this global burden, echinococcosis remains a neglected zoonosis. The importance of environmental factors in influencing the transmission intensity and distribution of Echinococcus spp. is increasingly being recognized. With the advent of climate change and the influence of global population expansion, food insecurity and land-use changes, questions about the potential impact of changing temperature, rainfall patterns, increasing urbanization, deforestation, grassland degradation and overgrazing on zoonotic disease transmission are being raised. This study is the first to comprehensively review how climate change and anthropogenic environmental factors contribute to the transmission of echinococcosis mediated by changes in animal population dynamics, spatial overlap of competent hosts and the creation of improved conditions for egg survival. We advocate rigorous scientific research to establish the causal link between specific environmental variables and echinococcosis in humans and the incorporation of environmental, animal and human data collection within a sentinel site surveillance network that will complement satellite remote-sensing information. Identifying the environmental determinants of transmission risk to humans will be vital for the design of more accurate predictive models to guide cost-effective pre-emptive public health action against echinococcosis.
A nationwide longitudinal study was conducted to investigate risk factors for bovine respiratory disease (BRD) in cattle in Australian feedlots. After induction (processing), cattle were placed in feedlot pens (cohorts) and monitored for occurrence of BRD over the first 50 days on feed. Data from a national cattle movement database were used to derive variables describing mixing of animals with cattle from other farms, numbers of animals in groups before arrival at the feedlot, exposure of animals to saleyards before arrival at the feedlot, and the timing and duration of the animal's move to the vicinity of the feedlot. Total and direct effects for each risk factor were estimated using a causal diagram-informed process to determine covariates to include in four-level Bayesian logistic regression models. Mixing, group size and timing of the animal's move to the feedlot were important predictors of BRD. Animals not mixed with cattle from other farms prior to 12 days before induction and then exposed to a high level of mixing (≥4 groups of animals mixed) had the highest risk of developing BRD (OR 3.7) compared to animals mixed at least 4 weeks before induction with less than 4 groups forming the cohort. Animals in groups formed at least 13 days before induction comprising 100 or more (OR 0.5) or 50-99 (OR 0.8) were at reduced risk compared to those in groups of less than 50 cattle. Animals moved to the vicinity of the feedlot at least 27 days before induction were at reduced risk (OR 0.4) compared to cattle undergoing short-haul transportation (<6h) to the feedlot within a day of induction, while those experiencing longer transportation durations (6h or more) within a day of induction were at slightly increased risk (OR 1.2). Knowledge of these risk factors could potentially be used to inform management decisions to reduce the risk of BRD in feedlot cattle.
Indigenous Australians with cancer are diagnosed with more advanced disease and have lower survival than other Australians. To investigate reasons for these differences. Retrospective cohort study of 1197 indigenous and nonindigenous people in the Northern Territory diagnosed with cancers of the colon and rectum, lung, breast, cervix and non-Hodgkin lymphoma between 1991 and 2000. Outcome measures were stage at diagnosis and relative risk of cancer death. Indigenous people compared with nonindigenous people had higher relative odds of advanced stage of cancer at diagnosis (relative odds 1.9, 95% CI 1.3-2.7) for four cancers but lower relative odds for lung cancer (relative odds 0.3, 95% CI 0.2-0.5). None of the potentially contributing factors examined could explain this difference. Risk of cancer death (adjusted for cancer type and age and stage at diagnosis) was higher in indigenous than in nonindigenous people (relative risk 1.7, 95% CI 1.4-2.1). This difference, however, was confined to indigenous people with an indigenous first language (relative risk 2.9, 95% CI 2.2-3.8). Adjustment for cancer treatment variables further reduced but did not eliminate this higher risk of death. Although more advanced stage at diagnosis appeared to be a sufficient explanation for poorer cancer outcome in indigenous people whose first language was English, poorer treatment also contributed to, but was still not sufficient to explain, poorer outcome in those who had an indigenous first language. Other factors, possibly including communication difficulties, knowledge of and attitudes to cancer symptoms and treatment and social and cultural 'distance' from mainstream health services, may also be involved.
Echinococcoses are parasitic diseases of major public health importance globally. Human infection results in chronic disease with poor prognosis and serious medical, social and economic consequences for vulnerable populations. According to recent estimates, the geographical distribution of Echinococcus spp. infections is expanding and becoming an emerging and re-emerging problem in several regions of the world. Echinococcosis endemicity is geographically heterogeneous and over time it may be affected by global environmental change. Therefore, landscape epidemiology offers a unique opportunity to quantify and predict the ecological risk of infection at multiple spatial and temporal scales. Here, we review the most relevant environmental sources of spatial variation in human echinococcosis risk, and describe the potential applications of landscape epidemiological studies to characterise the current patterns of parasite transmission across natural and human-altered landscapes. We advocate future work promoting the use of this approach as a support tool for decision-making that facilitates the design, implementation and monitoring of spatially targeted interventions to reduce the burden of human echinococcoses in disease-endemic areas.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-016-0109-x) contains supplementary material, which is available to authorized users.
This paper is based on the experience of the authors, with the aim to define the challenges for Echinococcus granulosus (E.g./CE) diagnosis and control for those countries that may now or in the future be contemplating control of hydatid disease. A variety of methods are available for diagnosis in humans but a universal gold standard is lacking. Diagnosis in definitive hosts can avoid necropsy by the use of methods such as coproantigen detection but test performance is variable between populations. A sylvatic cycle adds challenges in some countries and the epidemiology of the parasite in these hosts is poorly understood. Control by solely administering praziquantel to dogs is not effective in developing countries where the disease is endemic. Additional avenues to pursue include the instigation of participatory planning, use of an existing vaccination for intermediate hosts and development of a vaccine and long-acting anthelmitic implants for definitive hosts. Promoting public acceptance of control of the dog population by humane euthanasia and reduced reproduction is also essential.
dMycoplasma bovis is a pathogen of emerging significance in cattle throughout the world that is causing a range of diseases, including mastitis, arthritis, and pneumonia. The limited availability and efficacy of current diagnostic and prophylactic tools for its control and its increasing antimicrobial resistance are contributing to its increasing importance in beef and dairy cattle. We have developed an indirect IgG enzyme-linked immunosorbent assay (ELISA) based on a recombinant fragment of the MilA protein and have shown its potential as an effective diagnostic tool. To more comprehensively estimate the diagnostic sensitivity and specificity of this IgG ELISA for detection of infection with M. bovis in cattle and to define a suitable cutoff for use in the field, we further assessed its performance in experimentally infected calves in a closed beef herd and by applying Bayesian latent class modeling to laboratory testing results from 7,448 cattle entering Australian feedlots. The most effective cutoff points were estimated to be 68.6 antibody units (AU) for experimentally infected calves and to be 58.7 AU for a closed adult herd. Under field conditions, in feedlot cattle the globally optimal cutoff was estimated to be 105 AU. At this cutoff, the diagnostic sensitivity was 94.3% (95% probability interval [PI], 89.9% to 99.6%) with a diagnostic specificity of 94.4% (95% PI, 90.3% to 99.6%). Applying this 105 AU cutoff, 13.1% of cattle were seropositive for infection with M. bovis on entry into feedlots, and 73.5% were seropositive when followed up approximately 6 weeks later suggesting a high risk of infection shortly after entry into feedlots. Mycoplasma bovis is regarded to be an emerging cause of bovine respiratory disease (BRD) in veal calves, and infection can also cause polyarthritis and/or otitis media. In adult cattle, M. bovis is mainly associated with mastitis, keratoconjunctivitis, and reproductive tract disorders. Outbreaks of pneumonia induced by M. bovis have been reported throughout the world (1-3) and cause economic loss due to reduced weight gain and increased medication costs (4). The importance of M. bovis has been increasing because of increasing resistance to antimicrobial agents (5) and the lack of an effective vaccine (6). Transmission can occur through fomites, contact, or aerosol, and subclinically infected calves are believed to be carriers for life, so comingling of animals from different farms and age groups, combined with transport stress, results in outbreaks shortly after arrival in feedlots (7). Therefore, identification of infected source herds before introduction of animals to a naive group may help to prevent outbreaks (6).The gold standard for diagnosis of M. bovis infection is culture of the organism, but this is time-consuming and laborious. A M. bovis-specific PCR assay has been developed (8), but such assays are unlikely to be useful for herd screening, as excretion is only detectable for a limited time after infection. Serological diagnosis can be sensitive and inexpensive...
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