Toward proof of concept of a one health approach to disease prediction and control.

A One Health approach considers the role of changing environments with regard to infectious and chronic disease risks affecting humans and nonhuman animals. Recent disease emergence events have lent support to a One Health approach. In 2010, the Stone Mountain Working Group on One Health Proof of Concept assembled and evaluated the evidence regarding proof of concept of the One Health approach to disease prediction and control. Aspects examined included the feasibility of integrating human, animal, and environmental health and whether such integration could improve disease prediction and control efforts. They found evidence to support each of these concepts but also identified the need for greater incorporation of environmental and ecosystem factors into disease assessments and interventions. The findings of the Working Group argue for larger controlled studies to evaluate the comparative effectiveness of the One Health approach.

The LuxS-dependent quorum-sensing system regulates early biofilm formation by Streptococcus pneumoniae strain D39.

Streptococcus pneumoniae is the leading cause of death in children worldwide and forms highly organized biofilms in the nasopharynx, lungs, and middle ear mucosa. The luxS-controlled quorum-sensing (QS) system has recently been implicated in virulence and persistence in the nasopharynx, but its role in biofilms has not been studied. Here we show that this QS system plays a major role in the control of S. pneumoniae biofilm formation. Our results demonstrate that the luxS gene is contained by invasive isolates and normal-flora strains in a region that contains genes involved in division and cell wall biosynthesis. The luxS gene was maximally transcribed, as a monocistronic message, in the early mid-log phase of growth, and this coincides with the appearance of early biofilms. Demonstrating the role of the LuxS system in regulating S. pneumoniae biofilms, at 24 h postinoculation, two different D39ΔluxS mutants produced ∼80% less biofilm biomass than wild-type (WT) strain D39 did. Complementation of these strains with luxS, either in a plasmid or integrated as a single copy in the genome, restored their biofilm level to that of the WT. Moreover, a soluble factor secreted by WT strain D39 or purified AI-2 restored the biofilm phenotype of D39ΔluxS. Our results also demonstrate that during the early mid-log phase of growth, LuxS regulates the transcript levels of lytA, which encodes an autolysin previously implicated in biofilms, and also the transcript levels of ply, which encodes the pneumococcal pneumolysin. In conclusion, the luxS-controlled QS system is a key regulator of early biofilm formation by S. pneumoniae strain D39.

Bats, emerging infectious diseases, and the rabies paradigm revisited.

The significance of bats as sources of emerging infectious diseases has been increasingly appreciated, and new data have been accumulated rapidly during recent years. For some emerging pathogens the bat origin has been confirmed (such as lyssaviruses, henipaviruses, coronaviruses), for other it has been suggested (filoviruses). Several recently identified viruses remain to be 'orphan' but have a potential for further emergence (such as Tioman, Menangle, and Pulau viruses). In the present review we summarize information on major bat-associated emerging infections and discuss specific characteristics of bats as carriers of pathogens (from evolutionary, ecological, and immunological positions). We also discuss drivers and forces of an infectious disease emergence and describe various existing and potential approaches for control and prevention of such infections at individual, populational, and societal levels.