Month: October 2020

Identifying correlates of Guinea worm (Dracunculus medinensis) infection in domestic dog populations

Figure 1. Map of spatial hotspots of D. medinensis infection in dogs.

The eradication of human infectious diseases has proven remarkably difficult. The world has only succeeded once, in the case of the smallpox virus. However, international efforts have driven the debilitating Guinea worm parasite closer to the brink of eradication than nearly any other parasite. Coordinated efforts by the Ministries of Health in endemic countries, the U.S. Centers for Disease Control, The Carter Center, and the World Health Organization have reduced the number of annual Guinea worm cases from millions in the 1980s to hundreds in the early 2010s, but recently a new threat has emerged. Guinea worm infections have been diagnosed in domestic dogs, particularly in the Republic of Chad, and numbers of infections have continued to increase. As in many countries where dracunculiasis is endemic, the campaign for eradication in Chad has focused intervention measures on interrupting transmission among humans, so infection in dogs jeopardizes eradication efforts. In this study, we used machine learning methods to identify demographic, geographic, and climatic factors associated with the presence of Guinea worm-infected dogs at the village level, and spatial clustering of dog cases regionally. A combination of demographic, geographic and climatic factors were important correlates of infection at the village level, but the importance of these factors varied between northern and southern populations of the parasite. At the larger village cluster level, the geographic position and climate of a village were most important. Some of our findings, including the importance of fishing villages and the difference in correlates between northern and southern villages can be used by researchers to guide additional data collection and by public health workers to better target eradication efforts. More generally, this work contributes to a broader understanding of the spatial patterning of multi-host infectious diseases of humans and animals.

Richards RL, Cleveland CA, Hall RJ, Tchindebet Ouakou P, Park AW, Ruiz-Tiben E, Weiss A, Yabsley MJ, Ezenwa VO. Identifying correlates of Guinea worm (Dracunculus medinensis) infection in domestic dog populations. PLOS Neglected Tropical Diseases. 2020 Sep 14;14(9):e0008620. https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0008620

Laura Rack defends Ecology Master’s Thesis

Written by Mikey Fager, OSE undergraduate and Rosemond lab member

Humans and aquatic biota both rely heavily on the many services that river and stream systems provide. Water managers and conservation scientists need to determine the possible effects that increases in the frequency and duration of droughts due to climate change may have on ecosystem processes within these systems. Looking at the ways that different taxa in the systems respond to low-flow conditions can be immensely helpful in improving water infrastructure and management for both humans and aquatic organisms

Laura’s masters thesis research does just this, as she analyzed a variety of literature to assess how algae, invertebrates, and fishes respond to extended periods of low flow in streams and rivers, using the Upper Flint River Basin as her focal system. In the first two chapters, Laura hypothesized that algal biomasses would increase, while richness and density of aquatic invertebrates (particularly filter-feeders) and fish abundance would decrease during periods of low flows. She also outlined the different studies she would be reviewing for each taxonomic group, while noting the importance of considering study context such as stream size and average flow variation when drawing conclusions and discussing implications. Laura found that when low-flow events occur, abundance of algae generally increases, while the numbers of aquatic invertebrates and fishes tend to decline. She goes on to explain that droughts can lead to other events like loss of key plant species and warmer overall channel temperatures, which will likely compound the effects of low flows. Laura’s research expertly identifies the areas of concern that water managers, conservationists, and other stakeholders need to consider. Her work highlights essential research to be done towards understanding the explicit responses perennial systems have to low-flow events, in order for managers and ecologists alike to alleviate the stress that droughts may cause. 

Rack, L., 2020. Evaluating Low Streamflow Effects on Biota to Support Management in Perennial Systems. Master’s Thesis, University of Georgia.