We have seen 3 cases of Leptospirosis in the past three months. There are several factors for making this a real problem around here.
The main reason is that we are close to a ready source of water for wildlife (the Trinity River). And, the wildlife is living more in our yards. Leptospirosis is spread through the urine of infected animals.
Two of the cases we have seen had never been vaccinated for Lepto. Both were less than 5 pounds. We believe (now, more than ever) that even small dogs need to be vaccinated for Lepto, and have it as part of our core vaccines.
The third dog we saw was past due for her vaccinations by about a year. Lepto is one vaccine that has a very short immunity, and really needs to be updated regularly.