Editing Asymptomatic carrier (section)

=== A biological mechanism utilizing ''Salmonella'' ===
Numerous research publications have demonstrated how salmonella is able to remain in immune cells and alter their metabolic systems in order to further transmit the disease.<ref name=":3" /> Utilizing a closely related strand of bacterium (''S. typhimurium''), scientists have been able to create a mouse model that mimics the persistent salmonella cases seen in carriers of typhoid. Knowing that the bacterium can reside in mice for their entire lives, researchers have been able to determine that the bacterium tends to reside in [[macrophage]]s. Further examination of the gut lymph nodes of the mice reveals that ''S. typhimurium'' changes the inflammatory response of the macrophages.<ref name=":6">{{Cite journal|last1=Hersh|first1=David|last2=Monack|first2=Denise M.|last3=Smith|first3=Mark R.|last4=Ghori|first4=Nafisa|last5=Falkow|first5=Stanley|last6=Zychlinsky|first6=Arturo|date=1999-03-02|title=The Salmonella invasin SipB induces macrophage apoptosis by binding to caspase-1|journal=Proceedings of the National Academy of Sciences|language=en|volume=96|issue=5|pages=2396–2401|doi=10.1073/pnas.96.5.2396|issn=0027-8424|pmid=10051653|pmc=26795|bibcode=1999PNAS...96.2396H|doi-access=free}}</ref> Instead of eliciting an inflammatory response from the attack cells, the bacterium is able to convert them into an anti-inflammatory macrophage, allowing for optimal survival conditions. In the words of lead scientist [[Denise Monack]], "It wasn't that inflammatory macrophages were invulnerable to infection, but rather that, having infected a macrophage, ''S. typhimurium'' was much more able to replicate in the anti-inflammatory type".<ref name=":6" />

Investigators have also found that the presence of [[peroxisome proliferator-activated receptors]] (PPARs) correlated to the presence of salmonella bacterium. PPARs, thought of as roaming genetic switches, are responsible for the fat metabolism needed to sustain anti-inflammatory macrophages in which ''S. typhimurium'' hides.<ref name=":3" />