Local domestic animals have for years shouldered much of the blame for spreading drug-resistant salmonella to humans. A recent study from the Wellcome Trust Sanger Institute in the U.K. indicates that these animals may not be getting a fair shake.

The study, titled “Distinguishable Epidemics of Multidrug Resistant Salmonella Typhimurium DT104 In Different Hosts” and published in the journal Science, took place over 22 years, with researchers analyzing 373 DNA samples from both humans and animals infected with Salmonella Typhimurium DT104. 

During the sample analysis, researchers were often able to distinguish between salmonella populations in humans and animals, which was contrary to common assumptions. From this, researchers inferred that people likely were infected with salmonella from diverse sources instead of primarily animals.

Researchers also discovered that within the samples they analyzed, estimated instances of salmonella contamination being passed between animals and humans were “remarkably low,” and that there was greater diversity in antibiotic resistance genes in salmonellae isolated from humans, according to the study.

 “Taken together, these findings suggest that the contribution of local animal populations with S. Typhimurium DT104 may previously have been overstated,” Wellcome Trust Sanger Institute reported.