Hookworms are small worms that can spread if someone comes in contact with polluted sand or soil. 

How it spreads : Walking barefoot, kneeling, or sitting on the contaminated (with the stool of affected animals) ground can cause hookworm infection among people. Meanwhile, dogs can be exposed to this infection after swallowing the parasites or through their mother's milk or colostrum.

Who is at risk : Anyone can get infected with hookworms due to the aforementioned reasons.  

Signs in dogs : Symptoms including weight loss, anemia, and even life-threatening infections may appear in the puppies. 

Symptoms in People : Itchy reaction and a red squiggly line, where the parasite is present, are the most common symptoms that may appear in people. It's worth noting that both human and animal hookworms cannot survive in infected people or animals. Therefore, symptoms might disappear within 4-6 weeks without receiving medical treatment.