Source Tracking With DNA Andy Carson, Professor Veterinary Pathology (573) Bob Broz,University of Missouri Extension (573)

DNA SOURCE TRACKING The practice behind the procedure Species Specific e-coli found in all warm blooded species Each different species will have certain “markers” or “identifiers” that help us determine the possible source of e-coli.

DNA SOURCE TRACKING u Bacterial pollution associated with human or animal feces may contain pathogenic microbes which can cause human disease. u Fecal E. coli are non-pathogenic “indicators” of the possible presence of disease-producing organisms from human or animal feces. u Each strain of fecal E. coli has a “personal” DNA pattern/signature

DNA SOURCE TRACKING Build a Source Library of known contributors A source library from known species is developed for comparison to samples taken from unknown host. By comparing the DNA of the e- coli, we can determine where the contamination from bacteria is coming from.

DNA SOURCE TRACKING Sampling Each water sample is sub-divided into 12 sub-samples. This gives us a “picture” of what was in the water supply at that specific time. By sub-dividing the sample we can get a more accurate reading of the level of contamination from different species.

DNA SOURCE TRACKING Water sub-samples are put in a growth chamber and the e-coli is grown to determine what species are found in the sample.

u Fecal coliform – At 2 of 6 sites sampled, E. coli were beyond the state level of 200 pp/100 ml. Total countSource identified 2800Human, horse, cow 2000Cow, human, horse, sewage 4500Cattle, goose, human, sewage 920Sewage 138Sewage, human 200Cattle, horse, human 890Sewage, human, chicken

Areas in Missouri Where Source Tracking Is or Has Been Done Shoal Creek – Southwest Mo. Elk River – Southwest Mo. Jacks Fork – South Central Mo. Long Branch – North Central Mo. Brush Creek – West Central Mo. Bonne Femme – Central Mo. Others …….

DNA SOURCE TRACKING Dr. Carson’s lab was nationally recognized by EPA for accuracy and timeliness of process. 20 labs were selected using different forms of source tracking. University of Mo. ranked in the top three labs and had false positives in the samples that were submitted.

WHAT NEXT? New concepts and “markers” are being determined. Presently the “ribo-typing” procedure we use is expensive. The latest process for determining human contamination proves accurate and in- expensive. QUESTIONS?