Evaluating the Relationship Between Free-Living Biodiversity and Disease Risk Using Experimental Manipulations: An example from freshwater ponds of California

How changes in biodiversity affect infectious diseases remains largely unknown. As biodiversity on Earth continues to change, due both to invasive species introductions and native species losses, understanding this relationship will become increasingly important in the study of disease outbreak. Trematodes, which are parasitic flatworms with complex life cycles, offer a useful system in which to study the effects of change in biodiversity on rates of disease prevalence. Here, we used a field experiment to evaluate the effects of change in bird diversity and abundance on patterns of infections by trematode in California freshwater ecosystems. We deployed large-scale environmental manipulations designed to alter visitation rates by definitive avian hosts, either by attracting birds, deterring birds, or leaving bird behavior unchanged. We then measured the resulting bird visitation patterns through time-lapse photography. At each site, we also estimated the diversity and prevalence of trematode infections within freshwater snails, which function as the first intermediate hosts for trematodes. Our manipulations were highly effective at attracting birds, and “attractant” sites exhibited significantly higher bird abundance and richness relative to other treatments. Deterrent manipulations did not significantly reduce bird abundance and richness. Across all sites, bird richness correlated strongly with bird abundance, suggesting low levels of competition among host species, with implications for the potential of dilution in this ecosystem. Host abundance/richness were unrelated to infection prevalence, possibly owing to drought conditions at many study sites. These results suggest that large-scale manipulations can effectively alter patterns of host abundance and diversity with potential relevance for management

Framework for better living with HIV in England

Duration: April 2007 - May 2009 Sigma Research was funded by Terrence Higgins Trust to co-ordinate the development of a framework to address the health, social care, support and information needs of people with diagnosed HIV in England. It has now been published as the Framework for better living with HIV in England. The over-arching goal of the framework is that all people with diagnosed HIV in England "are enabled to have the maximum level of health, well-being, quality of life and social integration". In its explanation of how this should occur the document presents a road map for social care, support and information provision to people with diagnosed HIV in England. By establishing and communicating aims and objectives, the framework should build consensus and provide a means to establish how interventions could be prioritised and coordinated. The key drivers for the framework were clearly articulated ethical principles, agreed by all those who sign up to it, and an inclusive social development / health promotion approach. Sigma Research worked on the framework with a range of other organisations who sent representatives to a Framework Development Group (see below for membership). The framework is evidence-based and seeks to: Promote and protect the rights and well-being of all people with HIV in England. Maximise the capacity of individuals and groups of people with HIV to care for, advocate and represent themselves effectively. Improve and protect access to appropriate information, social support, social care and clinical services. Minimise social, economic, governmental and judicial change detrimental to the health and well being of people with HIV. Alongside the development of the framework, Sigma Research undertook a national needs assessment among people with diagnosed HIV across the UK called What do you need?. These two projects informed and supported each other. Framework Development Group included: African HV Policy Network Black Health Agency George House Trust NAM NAT (National AIDS Trust) Positively Women Terrence Higgins Trus