Various blood-sucking arthropods, especially ticks, can harbour leptospires
How is it Leptospirosis was a notifiable disease as long ago as 1968? Yet even now we can't get a proper notifiable status for Borreliosis?I think this 1969 paper might be interesting reading, to see what was known then about Leptospirosis:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1982058/pdf/brmedj02016-0061.pdf