Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/12/2006
Publication Date: 9/14/2006
Citation: Purdy, C.W., Raleigh, R., Straus, D., Elmurodov, B. 2006. Water pathogens present in the wastewater flow of a large dairy in the summer and winter. In: Proceedings of Conference on Monitoring of Spread and Prevention of Especially Dangerous Diseases of Animals and Birds, September 14-15, 2006, Samarkand, Uzbekistan. p. 20-23.
Interpretive Summary: Dairy wastewater is a valuable resource in semi-arid Southern High Plains region of the United States; however, this wastewater may contain fecal pathogens and toxins which potentially can be transmitted to mammals and birds exposed to the untreated wastewater. Lagoon wastewater is frequently used to settle the dust arising from dairy roads and animal pens. We determined that the dairy wastewater collected at 13 different sites along the wastewater flow during the winter and summer contained eight different serotypes of Salmonella enterica, and most wastewater samples collected contained Escherichia coli O157:H7. In addition, Listeria monocytogenes were found in mean concentrations of 10,000 to 100,000 /ml in the wastewater. Mean concentration of endotoxin (37,712 EU/ml or 8,321 ng/ml) was also found in the dairy wastewater. The isolation and identification of these pathogens and the endotoxin concentration should alert the dairy management of potential problems that may result from the improper reuse of non-chlorinated dairy wastewater when animals and humans are exposed.
Technical Abstract: Dairy wastewater is a valuable resource in semi-arid regions that can be recycled; therefore, its potential content of epizootic pathogens, endotoxins, and other hazardous substances is very timely and important. Bacterial and fungal epizootic pathogens were studied in wastewater on a 4,500 cow dairy in Southern High Plains, United States. The wastewater was collected in triplicate from 13 different collection points along the wastewater drainage system, starting in the milking parlor and ending in a lagoon; and from an irrigation center pivot that applied the lagoon wastewater mixed with fresh water to forage crops and later used as feed for dairy cows. Pathogens were found at all collections points, except two points where chlorination was used. Eight Salmonella serovars were identified; most wastewater samples contained Escherichia coli O157:H7; and Listeria monocytogenes was found in mean concentrations from 1 x 10**4 to 1 x 10**5 CFU/ml. The mean concentrations of Staphylococcus spp, (1 x 10**4 to 1 x 10**7CFU/ml) and Enterococcus spp (1 x 10**4 to 10 x10**5 CFU/ml) were also high. The mean concentration of mesophilic fungi ranged from 1 x 10**2 to 1 x 10**5 CFU/ml. The center pivot wastewater contained fewer of each pathogen studied and no Enterococcus spp were identified from this site. One of the most biologically active substances found in the lagoon wastewater was endotoxin which had a mean concentration of 37,712 EU/ml. These data show dairy wastewater can be a significant source of epizootic pathogens and endotoxin.