Fleas
Found outside anywhere your pet is comfortable (cool, shade etc.). According to capcvet.org, “Ctenocephalides felis is the most common ectoparasite of dogs in North America.”
They can cause skin irritation and transmit tapeworms. Flea infestations can lead to anemia and death, especially in puppies/kittens. It is recommended that puppies begin flea prevention as soon as possible, according to product guidelines. There are differences in prevalence geographically, and so treatment may differ by pet.

Roundworms
Studies suggest that nearly all puppies are born infected with roundworm. Accordingly, the CAPC recommends that puppies be dewormed every 2 weeks from age 2 weeks to 8 weeks, then placed on a monthly preventative that covers roundworms.

https://capcvet.org/maps/#2019/all/roundworm/dog/united-states/illinois/667-peoria-county/

Hookworm
Hookworms are zoonotic, meaning you can get them from your puppy! They suck blood, and can in some cases bleed a puppy to death. Control and prevention is important and easily done by applying a monthly preventative.

Other Intestinal Parasites
-Giardia, common among shelter dogs and those that visit dog parks
     -Keep your puppy away from feces/contaminated soil
-Whipworm
     -Consume blood and tissue in the intestine
     -Found worldwide, can cause bloody diarrhea and dehydration
     -Found in ~14% shelter dogs

-The CAPC recommends puppies have a fecal exam 4x during their first year, and 2x/year after
-Last year, up to 6% of dogs tested in Peoria County had some sort of intestinal parasite!
-Incidences of parasites were up to 8% in surrounding counties

Heartworm
Transmitted by mosquitos, heartworms can live up to 7 years inside of a dog’s body. Once infected, damage is done to the heart and lungs. Prevention is recommended year-round in all 50 states of the U.S. Prevention is recommended year-round.

https://capcvet.org/guidelines/heartworm/

Note! – 1% may seem low, but is still a significant number. This means that when in a typical week one vet sees 100 dog patients. Then there is at least 1 is heartworm positive dog, that week. That is 52 positive dogs a year. You should test annually and stay on prevention year round. to make sure your dog is negative.

https://capcvet.org/maps/#2019/all/heartworm-canine/dog/united-states/illinois/667-peoria-county/