[alex21]

I want to know about the various health problems caused by fleas on dogs. Is it a seasonal issue?

 

[LeoRose]

Where I live, fleas are a year round problem. Other than a lot of dogs (and cats) being allergic to flea bites and the resulting problems from scratching, fleas can carry the plague and tapeworm. Fleaborne diseases of the United States | CDC

 

[3GSD4IPO]

Adding: Fleas and their larva and eggs can quickly infest your house and then you need to clean spray and "insect bomb" your house.

This treatment may need to be repeated a couple of times.

Prevention is 9/10ths of the cure.

 

[DaySleepers]

Flea anemia is also a possibility with severe infestations on very young or very small dogs, though it's more common in cats. That shouldn't be a worry if you stay on top of things and prevent big infestations by treating for fleas when you first notice them, and never let your pets get overrun.

It's less common to find fleas outside during very cold seasons, but they can absolutely infest indoor spaces year round, even in cold climates. In warmer climates, they're absolutely a year round problem indoors and out.