Anyone who takes the time and effort to rescue a kitten's life deserves praise. However, doing so comes with certain needs and requirements. For example, many rescued kittens are crawling with fleas. If you've noticed fleas on your kitten, they need to go to a veterinarian as soon as possible. Here's why.
One of the most obvious reasons why your kitten should go to the vet is that they may be anemic from having their blood taken so many times. Flea bites drain a small amount of blood, which typically isn't enough to cause major health problems for adult cats. However, kittens have a much smaller blood volume since they are so little. If your kitten has been getting chewed on by fleas, it may not have as much blood as it should, which can risk its health. Thankfully, a thorough bath and anti-flea treatments from your vet should be able to keep this problem from getting worse.
Another possibility that comes with fleas is that your kitten may have worms. Tapeworms generally aren't spread from cat to cat, but rather from cat to flea to cat. Fleas can carry the larvae of tapeworms inside themselves harmlessly. Once a kitten eats or swallows one of these fleas, though, the larvae will hatch inside their intestines. In addition to being gross, tapeworm infestations can steal nutrients and calories from any food that your kitten eats. This is obviously dangerous and can stunt their growth or worse, so having your kitten tested and/or treated for worms is best.
Finally, there is another potential cause of anemia in kittens from fleas. As if the biting was not enough, fleas can transmit parasites like mycoplasma haemofelis that can damage the body's ability to build and replace blood cells. When combined with anemia from an excess of bites, this can keep your kitten from restoring its blood supply. If left untreated, the kitten's blood supply can become so low that it can die. Without enough blood, it's not possible for the body to send oxygen to the cells that desperately need it. There are also many other issues that can arise as a result of a lack of blood flow. However, it can generally be treated by getting rid of the fleas and giving the kitten antibiotics, so do not panic - just get to an animal hospital near you.