Atwill, Edward R., Conrad, Patricia A.
This project was developed to apply novel study designs and microbiology techniques to better understand and control fecal pollution flowing from terrestrial to aquatic ecosystems in California. The...
Interactions between Feral Horses and Desert Bighorn Sheep at Water (2008)
Stacey Ostermann-Kelm, Edward R. Atwill, Esther S. Rubin, Mark C. Jorgensen, Walter M. Boyce
We studied sympatric populations of native bighorn sheep (Ovis canadensis) and feral horses (Equus caballus) to quantify their spatial and temporal overlap and to determine whether horses interfered...
Management reduces E. coli in irrigated pasture runoff (2007)
Knox, A. Kate, Tate, Kenneth W., Dahlgren, Randy A., Atwill, Edward R.
Microbial pollutants, some of which can cause illnesses in humans, chronically contaminate many California water bodies. Among numerous sources, runoff from irrigated pastures has been identified as...
Exclosure size affects young blue oak seedling growth (2006)
Phillips, Ralph L., McDougald, Neil K., Atwill, Edward R., McCreary, Doug
Blue oak, a tree native only to California, is notoriously slow-growing, and its low regeneration rate has prompted concern about the species' future survival in some areas of the state. We studied...
Blue oak seedling age influences growth and mortality (2006)
Phillips, Ralph L., McDougald, Neil K., McCreary, Doug D., Atwill, Edward R.
In some California locations, the natural regeneration of blue oak is limited by the ability of small seedlings to survive long enough to become larger saplings. This study evaluated the growth and...
Conrad, Patricia A., Atwill, Edward R., Gardner, Ian A, Miller, Melissa, Leutenegger, Christian, Arkush, Kristen D, ...
Bivalve molluscs concentrate Cryptosporidium oocysts from fecal-contaminated aquatic environments and are useful for monitoring water quality. A real-time TaqMan polymerase chain reaction (PCR)...
Tate, Kenneth W, Van Kessel, Chris, Atwill, Edward R., Dahlgren, Randy A
This project examined the application of grass buffer strips to improve runoff water quality from irrigated pastures in the Sierra Nevada foothills. These flood irrigated pastures range up to 30%...
Atwill, Edward R., Phillips, Ralph, Rulofson, Franz
Cryptosporidium parvum (C. parvum) is a protozoal parasite that can cause gastrointestinal illness in a wide variety of mammals, including humans, livestock, companion animals, and wildlife. New...
Atwill, Edward R, Knight, Allen W, Tchobanoglous, George, Harp, James, Rose, Tamara L
Cryptosporidium parvum, a protozoal parasite, can be transmitted to humans through water and has become a major health concern. The ability to detect the oocysts of this parasite has been hampered by...
A direct immunofluorescence assay (DFA) (Merifluor; Meridian Diagnostics, Inc., Cincinnati, Ohio) was compared to an immunomagnetic separation (IMS) assay (Dynabeads; Dynal, Inc., Lake Success, N.Y.)...
Atwill, Edward R., Camargo, Sergio Maldonado, Phillips, Ralph, Alonso, Laura Herrera, Tate, Kenneth W., Jensen, Wayne A., ...
Sixteen percent of California ground squirrels (Spermophilus beecheyi) were found to be shedding an average of 53,875 Cryptosporidium parvum oocysts/g of feces. Male squirrels had a higher prevalence...
DNA Sequence Similarity between California Isolates of Cryptosporidium parvum
Atwill, Edward R., Crawford, Melissa R., Lefebvre, Rance B.
We evaluated whether nucleic acid amplification with primers specific for Cryptosporidium parvum followed by automated DNA sequence analysis of the PCR amplicons could differentiate between...
Atwill, Edward R., Hou, Lingling, Karle, Betsy M., Harter, Thomas, Tate, Kenneth W., Dahlgren, Randy A.
Vegetated buffer strips were evaluated for their ability to remove waterborne Cryptosporidium parvum from surface and shallow subsurface flow during simulated rainfall rates of 15 or 40 mm/h for 4 h....
Atwill, Edward R., Phillips, Ralph, Li, Xunde, McCowan, Brenda
Twelve percent of 853 California ground squirrels (Spermophilus beecheyi) from six different geographic locations in Kern County, Calif., were found to be shedding on average 44,482 oocysts g of...
Association of Cryptosporidium parvum with Suspended Particles: Impact on Oocyst Sedimentation
Searcy, Kristin E., Packman, Aaron I., Atwill, Edward R., Harter, Thomas
The association of Cryptosporidium parvum oocysts with suspended particles can alter the oocysts' effective physical properties and influence their transport in aquatic systems. To assess this...
Deposition of Cryptosporidium Oocysts in Streambeds
Searcy, Kristin E., Packman, Aaron I., Atwill, Edward R., Harter, Thomas
The transfer of Cryptosporidium oocysts from the surface water to the sediment beds of streams and rivers influences their migration in surface waters. We used controlled laboratory flume experiments...
A direct immunofluorescence assay (DFA) (Merifluor; Meridian Diagnostics, Inc., Cincinnati, Ohio) was compared to an immunomagnetic separation (IMS) assay (Dynabeads; Dynal, Inc., Lake Success, N.Y.)...
Atwill, Edward R., Camargo, Sergio Maldonado, Phillips, Ralph, Alonso, Laura Herrera, Tate, Kenneth W., Jensen, Wayne A., ...
Sixteen percent of California ground squirrels (Spermophilus beecheyi) were found to be shedding an average of 53,875 Cryptosporidium parvum oocysts/g of feces. Male squirrels had a higher prevalence...
DNA Sequence Similarity between California Isolates of Cryptosporidium parvum
Atwill, Edward R., Crawford, Melissa R., Lefebvre, Rance B.
We evaluated whether nucleic acid amplification with primers specific for Cryptosporidium parvum followed by automated DNA sequence analysis of the PCR amplicons could differentiate between...
Atwill, Edward R., Hou, Lingling, Karle, Betsy M., Harter, Thomas, Tate, Kenneth W., Dahlgren, Randy A.
Vegetated buffer strips were evaluated for their ability to remove waterborne Cryptosporidium parvum from surface and shallow subsurface flow during simulated rainfall rates of 15 or 40 mm/h for 4 h....
Atwill, Edward R., Phillips, Ralph, Li, Xunde, McCowan, Brenda
Twelve percent of 853 California ground squirrels (Spermophilus beecheyi) from six different geographic locations in Kern County, Calif., were found to be shedding on average 44,482 oocysts g of...
Association of Cryptosporidium parvum with Suspended Particles: Impact on Oocyst Sedimentation
Searcy, Kristin E., Packman, Aaron I., Atwill, Edward R., Harter, Thomas
The association of Cryptosporidium parvum oocysts with suspended particles can alter the oocysts' effective physical properties and influence their transport in aquatic systems. To assess this...
Deposition of Cryptosporidium Oocysts in Streambeds
Searcy, Kristin E., Packman, Aaron I., Atwill, Edward R., Harter, Thomas
The transfer of Cryptosporidium oocysts from the surface water to the sediment beds of streams and rivers influences their migration in surface waters. We used controlled laboratory flume experiments...
Capture and Retention of Cryptosporidium parvum Oocysts by Pseudomonas aeruginosa Biofilms
Searcy, Kristin E., Packman, Aaron I., Atwill, Edward R., Harter, Thomas
The association of Cryptosporidium oocysts with biofilm communities can influence the propagation of this pathogen through both environmental systems and water treatment systems. We observed the...
Miller, Woutrina A., Lewis, David J., Lennox, Michael, Pereira, Maria G. C., Tate, Kenneth W., Conrad, Patricia A., ...
Climatic factors and on-farm management practices were evaluated for their association with the concentrations (cyst/liter) and instantaneous loads (cysts/second) of Giardia duodenalis in storm-based...