From Puppy Training Secrets info on fleas

With summer just about to be upon us [hopefully!] in the Northern Hemisphere the following advice is at its most pertinent. As the warmer months are a prime time for pests such as fleas to spread - also watch out for ticks - it is a time to be vigilant and to check your pet regularly.

"It is very important that fleas are dealt with promptly, as they
can spread disease such as tapeworm, typhus and tularemia. Not only
that, but the itching can drive your poor dog crazy!...."

The above advice within quotes is from a newsletter I get from the following website... SitStayFetch: Dog Training To Stop Your Dogs Behavior Problems... you could find out more by clicking the link!