Among bird sample was bird species or size a factor positivity rate?
We did not systematically evaluate bird species or fecal size as factors associated with STEC positivity.
Bird fecal samples varied widely in size, and in some cases were composited, potentially representing more than one bird or species.
Because all available fecal material was typically used for STEC testing, species identification was not performed for most samples. However, mitochondrial DNA identification was conducted on a subset. Among these, STEC-positive samples were identified as originating from crow, dove, hawk, and raven. STEC-negative samples were identified as blackbird, Canada goose, chicken, crow, dove, raven, and starling.
Does the emergence of similar strains in locations that are far apart (50-70 miles) from each other mean they are somehow connected or come from the same source? Why is this finding so significant?
We can only speculate why and how similar strains of STEC appear at different locations at different times. Finding a highly related strain between two locations does not mean those two locations are directly linked by some singular transmission pathway. It is possible that there are multiple intervening steps, some historical, that played a role in prior dissemination of the strain, like a complicated network of transmission, amplification, and inactivation pathways leading to a patchwork of detected positives throughout the study region.
Early on there was mention of a wildlife bucket. What is that?
A “wildlife bucket” refers to a 5-gallon bucket buried in the soil beneath the drip irrigation line at one vineyard site. During irrigation, the bucket collected and held water, providing a drinking source for wildlife. This approach was implemented only along the vineyard rows adjacent to a riparian/rangeland area, where animal activity was most frequent. The intent was to discourage animals from chewing on irrigation lines to access water, thereby reducing damage and leaks.
How do you explain aged feces having more O157? It has to get there somehow.
We can only speculate as to why, in wildlife scat, there was a higher prevalence of E. coli O157:H7 in aged versus fresh scat. One explanation is that this was random chance observation. Alternatively, this strain of STEC may have replicated in the fresh scat after being deposited in the environment, and then persisted in the aged material such that bacterial detection was easier in the laboratory.
One table said rodents were not included but rabbits and squirrels were on the table. Does that mean rats and mice were not included? Did you find or sample feces from mice or gophers? (didn’t see it listed in the table). If so, why were they not included?
Wildlife fecal sample collection was opportunistic, and samples were collected only when encountered in the field. Gophers, mice, and rats were not specifically identified among fecal samples included in the metagenomic analysis.