This sounds a lot like what I experienced in May. Vet
thought it was a equine influenza (flu). Turned out, after 6 horses became
ill, we finally had one develop a very small (thumbnail sized ) lump under the
jaw: STRANGLES!!! Strangles was confirmed in 3 of 12 ill
horses. One developed a normally rare complication called purpura and was
in the hospital for 18 days.
If you want more info about our experience (including the fact
that we still do not know where it came from) of having 12 ill horses from
Strangles, please email me privately at rainbowmeadowsranch@xxxxxxxxx
