Reduction of pathogen indicator organisms in dairy wastewater using an ecological treatment system.

Ecological treatment systems can provide a sustainable, plant-based alternative to traditional wastewater treatment. One factor essential to the success of these systems is ensuring their ability to reduce coliform concentrations in wastewater. Wastewater is the primary source of fecal contamination in aquatic ecosystems, containing total and fecal coliforms on the order of 10(8)-10(10) and 10(7)-10(9) CFU L(-1), respectively. This study assessed the ability of an ecological treatment system to reduce concentrations of total coliforms and Escherichia coli from dairy wastewater. Low strength wastewater was pumped into the system during July of 2005 and high strength in September 2005. Wastewater passes through a series of anaerobic, aerobic, and clarifier reactors and wetland cells before exiting the system. Regardless of wastewater strength, average total coliform and E. coli concentrations were consistently reduced by at least 99% from influent to effluent, with the majority of the reduction (76%) occurring in the first two reactors. Relationships between internal concentrations of solids and coliforms indicated that increased reduction of solids may further reduce coliform concentrations. Although U.S. Environmental Protection Agency discharge requirements for E. coli were not always met, the substantial reductions achieved indicate that ecological treatment systems have the potential to successfully reduce coliforms in wastewater to meet discharge limits. The results from this study will be used to guide design and management of future ecological treatment systems, so that larger and more consistent coliform reductions can be achieved.

Survey of parasites and bacterial pathogens from free-living waterfowl in zoological settings.

To determine if free-living waterfowl residing in a zoological setting pose health risks for its animal collections, visitors, and employees, 450 fecal samples were collected and cultured for the presence of Campylobacter jejuni, Escherichia coli, Salmonella spp., and Pasteurella multocida. A survey of endoparasites infecting the waterfowl was also conducted. Sixty-seven percent, 42%, and 1.7% of the samples tested positive for E. coli, C. jejuni, and Salmonella spp., respectively. No P. multocida was isolated from the sampled population. Antimicrobial susceptibility testing for the bacterial isolates demonstrated that a majority of the isolates were susceptible to the antibiotics tested. A survey for parasites revealed 16% of the samples had coccidia oocytes; 8% of the sample had spirurid ova; and 17% of the sample had strongylate-type nematode ova. Ascaris spp. ova, Capillaria spp. ova, oxyurid ova, and mites were also noted in some fecal samples.

Adapting a case-based, cooperative learning strategy to a veterinary parasitology laboratory.

INTRODUCTION: Third-year veterinary students participate in a parasitology laboratory for instruction in diagnostic techniques. Course instructors adapted a case-based, cooperative learning approach to stimulate student involvement. Previously, students worked individually but shared common equipment in small groups. Peer interactions and discussions were not inherent in the format. Specimens were provided for practicing diagnostic techniques. METHODOLOGY: Students were assigned to cooperative learning groups of four students. Within each group, members were assigned distinct roles that rotated daily. Samples were presented as clinical cases, including history and signalment. Within groups, students performed role-specific duties and were expected to teach their component to other group members. Groups worked up their case for presentation to the class at the end of each period. Grading was unchanged from previous years, based on four individual quiz scores, two case reports, and a final practical exam. RESULTS: Student grades remained satisfactory and student feedback was highly favorable, the most common response being that group work enhanced understanding and that a case-based approach provided valuable clinical insights. An important comment was that peer teaching could be inconsistent; some students were concerned that important information was overlooked during the reciprocal teaching. Their recommendation was to verbalize expectations more clearly and to work with groups to facilitate reciprocal teaching.