A New Model For The Pathogenesis Of Rheumatic Fever: Superantigen Priming Of The Immune Response To Group A Streptococci
Funder
National Health and Medical Research Council
Funding Amount
$248,820.00
Summary
Acute rheumatic fever (ARF) is now rare in developed countries. However, it remains a major problem in Aboriginal Australians in the NT where the rate of ARF is the highest in the world. This leads to high rates of rheumatic heart disease (up to 3% of individuals in some communities) and a premature mortality of over four times that for developing countries. Immunisation and improved living conditions offer a long-term solution but these remain a distant prospect. In the short and medium term, c ....Acute rheumatic fever (ARF) is now rare in developed countries. However, it remains a major problem in Aboriginal Australians in the NT where the rate of ARF is the highest in the world. This leads to high rates of rheumatic heart disease (up to 3% of individuals in some communities) and a premature mortality of over four times that for developing countries. Immunisation and improved living conditions offer a long-term solution but these remain a distant prospect. In the short and medium term, control of this ARF will partly depend on new and better treatment and prevention strategies. To achieve these goals a deeper understanding of the immune mechanisms underlying this disease is urgently needed. It is known that ARF is caused by an abnormal immune response following streptococcal infection. This leads to the production of cells called T cells that attack the body s own tissues rather than the bacteria itself. This autoimmune disease is responsible for the heart damage that underlies ARF. It is believed that this proces only occurs when susceptible individuals are infected with specific rheumatogenic strains of streptococci. However there are a number of deficiencies in this model and it is proposed that there is an additional factor responsible for the abnormal immune response in ARF. This project will explore the possibility that bacterial toxins called superantigens are the critical missing factor , by studying the immune response in ARF. Superantigens are produced by certain streptococci and staphylococci, and are potent in minute quantities causing widespread activation of the immune system. They have been found to play an important role in a number of autoimmune diseases and the type of immune response found in ARF fits well with that expected if superantigens were involved. If superantigens play an important role in causing the abnormal immune response in ARF then a number of new avenues would open for the treatment and prevention of this disease.Read moreRead less
Mathematical Modelling Of Bacterial Carriage In Children
Funder
National Health and Medical Research Council
Funding Amount
$421,746.00
Summary
Children exposed to larger numbers of other children are at risk of persistent bacterial infections. Such circumstances explain the high rates of ear and chest infections, and skin sores seen in children in historical times. Changing social circumstances (smaller families, better housing, nutrition and hygiene), as well as the introduction of antibiotics, explain the decline of such infections in affluent communities since the early 20th century. However, even today, in affluent countries, child ....Children exposed to larger numbers of other children are at risk of persistent bacterial infections. Such circumstances explain the high rates of ear and chest infections, and skin sores seen in children in historical times. Changing social circumstances (smaller families, better housing, nutrition and hygiene), as well as the introduction of antibiotics, explain the decline of such infections in affluent communities since the early 20th century. However, even today, in affluent countries, children attending group child care are at high risk of ear infections. As many bacteria are resistant, antibiotics are now much less effective than when they were first introduced. Furthermore, there is a continuing load of infection for children in Aboriginal communities, in PNG and other developing countries, causing hearing loss, chronic respiratory problems, and heart disease and renal disease in later life. Using data previously collected from other studies in Indigenous communities and children in child care, mathematical models allow us to ask what if?, and answer important public health questions: 1. What environmental and public health measures can reduce the cycle of cross-infection in child-care and high-risk populations? 2. What coverage rates with pneumococcal vaccine will eliminate the vaccine-specific bacteria from child care centres, from the wider community, and from high risk populations? 3. Will infections with bacteria not covered by vaccine then increase? 4. Will the resistant bacteria tend to disappear if antibiotic use is restricted? 5. Under what circumstances will antibiotics help to control infection? The modelling will promote understanding of the social and health costs of bacterial infection in Aboriginal communities and child care and use educational scenarios to promote uptake of the most cost-effective and socially acceptable interventions.Read moreRead less
Clinical Impact Of Clonal Pseudomonas Aeruginosa In Cystic Fibrosis
Funder
National Health and Medical Research Council
Funding Amount
$547,238.00
Summary
In patients with cystic fibrosis (CF), the normal defence mechanisms are compromised by an inherent genetic fault which results in an extremely sticky and dehydrated mucus. The respiratory system is unable to eradicate microbes (infection) from the lungs of patients with CF which begin to multiply and cause infection and inflammation. Recurring infections are treated with multiple courses of antibiotics and frequent hospitalisation and eventually result in premature death. This study focuses on ....In patients with cystic fibrosis (CF), the normal defence mechanisms are compromised by an inherent genetic fault which results in an extremely sticky and dehydrated mucus. The respiratory system is unable to eradicate microbes (infection) from the lungs of patients with CF which begin to multiply and cause infection and inflammation. Recurring infections are treated with multiple courses of antibiotics and frequent hospitalisation and eventually result in premature death. This study focuses on the major bacterial problem, Pseudomonas aeruginosa. Several studies from Australia and the UK, including our own have shown that about 30% to 45% of patients share the same strain of Pseudomonas aeruginosa within a centre. We know that two dominant strains of Pseudomonas aeruginosa are found in CF centres on the eastern board of Australia. This is unexpected as this bacterium is usually acquired from the environment. The emergence of these clonal strains is causing increasing anxiety in the CF community. This study is designed to provide vitally needed information on the clinical implications of being infected by an clonal strain of Pseudomonas aeruginosa and the risk factors for the acquisition of an clonal strain. This new information will provide a rationale basis for the need for changes to infection control policies (including patient segregation), better outcome predictors for patients infected with clonal strain of Pseudomonas aeruginosa.Read moreRead less
Cluster Randomised Trial Comparing One Versus Two Doses Of Ivermectin For Mass Drug Administration To Control Scabies
Funder
National Health and Medical Research Council
Funding Amount
$540,512.00
Summary
Scabies is a common skin disease in developing countries, in particular in the Pacific region. In the Western Province of Solomon Islands, one in two children suffer from the infestation, and 20% of the population. We know that mass drug administration with two doses of oral ivermectin is effective to reduce the burden of scabies in the community. We now propose a study to determine whether one single dose is as effective. This would have major public health benefits.
Does Mass Drug Administration For Scabies Result In Control Of Serious Bacterial Complications? A Proof Of Concept Towards Global Elimination.
Funder
National Health and Medical Research Council
Funding Amount
$883,760.00
Summary
Scabies is common skin disease in developing countries, in particular in the Pacific region. In Fiji, one in two children suffer from the infestation, which affects over 20% of the population. A recent study conducted in Fiji on 2000 people showed that mass drug administration (MDA) with oral ivermectin is a safe and effective way to reduce the burden of scabies in the community. We will expand the MDA program to 100,000 people, the largest study of MDA ivermectin for scabies ever undertaken.
Estimating The Burden Of Group A Streptococcal Diseases In Victoria
Funder
National Health and Medical Research Council
Funding Amount
$386,760.00
Summary
Despite the considerable advances in the diagnosis and treatment of group A streptococcal (GAS) diseases made during the last century, the impressive spectrum of infections caused by this organism continues to have a significant impact in developed countries. This spectrum includes diseases that are mild but common (e.g. sore throat, skin sores), rare but very severe (e.g. bloodstream infections, flesh-eating bacteria) and those that are more common in developing countries and the Aboriginal pop ....Despite the considerable advances in the diagnosis and treatment of group A streptococcal (GAS) diseases made during the last century, the impressive spectrum of infections caused by this organism continues to have a significant impact in developed countries. This spectrum includes diseases that are mild but common (e.g. sore throat, skin sores), rare but very severe (e.g. bloodstream infections, flesh-eating bacteria) and those that are more common in developing countries and the Aboriginal population (e.g. rheumatic fever, kidney disease). Streptococcal sore throat remains one of the most common childhood infections, and severe group A streptococcal diseases are thought to be increasing in incidence in Australia. Yet, there are no accurate data on the incidence and costs of these or other GAS diseases in non-Aboriginal Australians, or in most other populations around the world. It is becoming more urgent to collect this data as numerous vaccine candidates are entering human trials, new approaches to the treatment of sore throat are emerging, and new strategies to treat and control the spread of severe disease are being developed. We propose a comprehensive strategy to measure the incidence, prevalence and costs of each group of GAS diseases. We will follow a group of families for 12 months to detect cases of GAS sore throat and skin sores and measure the impact on the family. We will survey children in schools to estimate the prevalence of skin sores. We will check hospital records to calculate the number of cases of rheumatic fever and kidney disease. And we will maintain surveillance for severe diseases by checking hospital and laboratory records. We will also check to see if family members of people with severe disease have the GAS bacterium in their throats. We will then compile these data into a comprehensive estimate of the burden of disease in Victoria, and estimate the cost-effectiveness of different treatment and prevention strategies.Read moreRead less
Anti-sporulation Strategies For Clostridium Difficile Infections
Funder
National Health and Medical Research Council
Funding Amount
$651,559.00
Summary
Hospital-acquired infections with the bacterium Clostridium difficile are a major global public health concern with highly virulent isolates emerging overseas in 2002 and in Australia in 2010. These strains have spread through our hospitals and are also found in the community. This project will increase our understanding of how these strains spread and will provide knowledge that is critical for developing improved strategies for preventing these infections.
A Randomised Placebo-controlled Trial Of Antibiotics To Prevent Urinary Tract Infection In Children
Funder
National Health and Medical Research Council
Funding Amount
$735,000.00
Summary
This study is needed to determine whether a common clinical practice long-term antibiotic treatment for children following urinary tract infection (UTI) - is safe and effective in preventing further UTI and if so, whether all appropriate children are being treated. UTI will affect about 10% of Australian children by high school age (88,000 children per year). Because UTI may damage the kidneys, the management priority for children with UTI has been prevention of further infection. Currently this ....This study is needed to determine whether a common clinical practice long-term antibiotic treatment for children following urinary tract infection (UTI) - is safe and effective in preventing further UTI and if so, whether all appropriate children are being treated. UTI will affect about 10% of Australian children by high school age (88,000 children per year). Because UTI may damage the kidneys, the management priority for children with UTI has been prevention of further infection. Currently this means the identification of children thought to be most at risk of recurrent UTI by renal tract imaging. Those found to have reflux of urine from the bladder to the kidney (present in about 30% of those with UTI) are then placed on antibiotics fro 2-5 years. Unfortunately there has never been a properly designed trial to test whether antibiotics do really prevent UTI and if so, whether children with reflux are the appropriate and only group requiring treatment. Long term antibiotics may in fact do more harm than good because of side effects like skin, bowel and blood problems and because resistant bacteria may develop. The design of this study involves the random allocation of placebo or antibiotic (cotrimoxazole, the usual antibiotic given in this case) to about 800 children after their first symptomatic UTI. These children are treated and followed for one year to determine the rate of futher UTI in both groups. Any difference in outcome between the two groups of children will be because of the antibiotic treatment. This study may prove long-term antibiotics are ineffective and therefore should not be routinely used. In this case investigation of children to detect vesicoureteric reflux would serve little purpose and should be abandoned. Alternatively antibiotic treatment may be shown as effective treatment for preventing further UTI and in this case the study will clearly identify those children who will benefit.Read moreRead less
Population-level Epidemiological Trends In Hepatocellular Carcinoma In Queensland 1996 - 2010.
Funder
National Health and Medical Research Council
Funding Amount
$251,695.00
Summary
Incidence and mortality of hepatocellular carcinoma (HCC, the most common form of liver cancer) is increasing in Australia, driven by viral hepatitis infections. Disease burden is not defined in Queensland, particularly for Indigenous, migrant and regional and remote communities. Such factors may influence risk of viral hepatitis, access to treatment, and incidence and survival of HCC. Defining disease burdens will enable clinical programs targeted at groups most at risk in order to impact HCC t ....Incidence and mortality of hepatocellular carcinoma (HCC, the most common form of liver cancer) is increasing in Australia, driven by viral hepatitis infections. Disease burden is not defined in Queensland, particularly for Indigenous, migrant and regional and remote communities. Such factors may influence risk of viral hepatitis, access to treatment, and incidence and survival of HCC. Defining disease burdens will enable clinical programs targeted at groups most at risk in order to impact HCC trends.Read moreRead less
A Unique Network Of Phagocytic Cells At The Interface Between The Liver And Peritoneal Cavity
Funder
National Health and Medical Research Council
Funding Amount
$787,521.00
Summary
This project aims to characterise the nature and ontogeny of a novel population of cells with phagocytic capacity that forms a network underlying the capsule of mouse and human liver reminiscent of that formed by Langherans cells in the epidermis of the skin. In this project we will characterise this newly described liver capsular macrophage subset, define their ontogeny and assess their specific functions.