Can dogs pass on heartworms to humans?

Yes, humans can get heartworm, although it is very rare. It is most common for humans to get heartworm by being bitten by a mosquito, which then deposits the larvae for the heartworm into the human. Even then, heartworm in humans is usually found in the lungs and isn't severe. There have been some cases in which humans got diseases from heartworm. Heartworm can also be transmitted by 'flies, ticks, fleas, and lice'. See related Source link below.