no association between presence of measles vaccine virus in the gut of children and whether these children had autism, nor was there an association between MMR exposure and autism. In 2011, she co-authored another study concluding that autistic children have altered expression of genes involved in digestion. Regarding this study, Hornig said that its results "are consistent with other research suggesting that autism may be a system-wide disorder, and provide insight into why changes in diet or the use of antibiotics may help alleviate symptoms in some children." In 2015, Hornig co-authored a study that found that chronic fatigue syndrome (CFS) in the early stages of the disease had higher levels of cytokines than people without CFS. Animal models In the 1990s, Hornig helped to develop an infection-based model of neurodevelopmental disorders, such as autism and depression, based on neonatal rat infection with Borna disease virus. In 2004, Hornig published a controversial paper concluding that, in a highly inbred strain of mice which is unusually susceptible to autoimmune disease, administration of thimerosal resulted in the development of autism-like symptoms; specifically, "growth delay; reduced locomotion; exaggerated response to novelty; and densely packed, hyperchromic hippocampal neurons with altered glutamate receptors and transporters." In addition, in an interview with the Los Angeles Times, Hornig contended that thimerosal may be linked to the recent increases in the incidence of autism. However, Paul Offit has accused Hornig of overstating her findings, arguing that her study was "a far cry from proving that thimerosal caused autism in children," and Steven Goodman, a member of the IOM panel that rejected a thimerosal-autism link in 2004, shortly before Hornig's study was published, has claimed that this study "in no way substitutes for actual human evidence." Additionally, researchers from the University of California, Davis were unable to reproduce Hornig's results despite using the same strain of mice and ten times the amount of mercury used in Hornig's study. In 2006, Dan Olmsted reported that Hornig was working on a treatment program in which she would administer gold salts to these genetically susceptible mice in an attempt to improve their behavior. In 2009, Hornig published another study using mice to examine the mechanism by which Group A beta-hemolytic streptococcus infections might cause Tourette's syndrome, OCD and tics, in line with the PANDAS hypothesis. Hornig stated that her findings "illustrate that antibodies alone are sufficient to trigger this behavioral syndrome." Personal