When Strep equi Isn't Really Strep equi
Microbiologists like to confuse people. The names of different bacteria are often changed as new information is discovered and species are grouped, separated or completely reclassified. One can imagine that this eventually makes for some confusing situations.
One example of this is Streptococcus equi (aka Strep equi), the cause of the highly infectious disease strangles, and its close relative Streptococcus zooepidemicus (aka Strep zoo). Streptococcus zooepidemicus is commonly found in the respiratory tracts of healthy horses and can cause secondary infections, but it is not highly transmissible like Strep equi. Technically, however, both of these organisms are actually Streptococcus equi. The S. equi that causes strangles is Streptococcus equi subspecies equi, while the other one is Streptococcus equi subspecies zooepidemicus. Usually, people just refer to them as S. equi and S. zooepidemicus for simplicity's sake, and in most situations, that's enough for people to understand what they're dealing with. However, sometimes there can be confusion if a diagnostic laboratory reports the full name of the organism and someone doesn't notice the "zooepidemicus" at the end, and panic ensues about a non-existent strangles case/outbreak until someone reads the report properly. The take-home message here is read all diagnostic test results carefully and if in doubt, call for clarification.
