Officials from two federal agencies yesterday announced that Colorado State University received a $1.2 million, five-year Ecology of Infectious Diseases, or EID, grant to conduct research on how large-scale climate events alter outbreaks of the plague. The research, funded jointly by the National Science Foundation and the National Institutes of Health, will help predict and minimize incidence of plague in expanding human populations of the western United States.
"By identifying species involved in the maintenance and transmission of plague and the environmental factors associated with outbreaks of the disease, this research will help explain how plague persists, how it is transmitted from one species to another and how we can predict outbreaks and protect humans," said Michael Antolin, professor of biology at Colorado State and principal investigator of the project. "The results could help create both effective public health and species conservation policy."
Plague continues to be a serious human health concern, with up to 3,000 worldwide cases reported yearly.
Antolin and his research group, including collaborators at Colorado State, the Centers for Disease Control and California State University-Fullerton, will investigate the ecological drivers of rodent-borne plague outbreaks, specifically in populations of black-tailed prairie dogs. Northern Colorado prairie dogs are highly susceptible to mortality from plague and provide an ideal model to study mechanisms regarding the persistence and spread of the disease.
The research is being conducted northeast of Fort Collins on the Pawnee National Grassland in conjunction with long-term plague surveillance conducted as part of the Short Grass Steppe Long Term Ecological Research project, also funded by the National Science Foundation. Information about the program is available on the Web at http://sgs.cnr.colostate.edu.
Scientists have learned that serious outbreaks of infectious diseases in natural populations of animals can occur when environmental factors, such as a variation in temperature or precipitation, influence the population density of animals who carry the disease or the size of flea and other insect populations that transmit disease. The Colorado State team’s own data indicate a significant link between plague outbreaks in northern Colorado prairie dog colonies and El-Nino years, further suggesting an association between weather events and plague outbreaks.
However, exactly how plague changes from explosive outbreaks to lulls when the disease falls to almost undetectable levels is unknown, and precisely how this relates to weather events remains to be explored. The Colorado State-led research team hopes to clarify this information.
The aim of the research is to determine how plague persists and is transmitted among colonies and, in between outbreaks, whether the plague remains at very low levels in colonies or their fleas, or if the disease only moves into grasslands from other habitats following weather-related increases in densities of these other rodents.
"It is increasingly apparent that local prevalence and outbreaks of infectious disease can be influenced by large-scale climatic patterns," said Antolin. "Among other goals, our project is striving to determine the specific mechanisms regarding climate events and outbreaks or lulls in plague."
An extensive field monitoring program will be established to identify centers of plague in populations of prairie dogs, other small rodents and their fleas before, during and after large outbreaks of the disease. These studies, along with laboratory experiments to determine the susceptibility of fleas associated with different rodents, will help the research team identify potential routes of infection as well as the ability of plague to persist in flea populations in the absence of large rodent colonies.
The joint NSF/NIH Ecology of Infectious Diseases program supports efforts to understand the underlying ecological and biological mechanisms that govern relationships between human-induced environmental changes and the emergence and transmission of infectious diseases. The EID program strives to make significant breakthroughs in the ability to predict, prevent and mitigate disease outbreaks.