Sometimes, the biggest threat to your cat’s health is the smallest in size. Parasites are ever-present in a cat’s environment, especially if they like to roam the great outdoors. The first step in protecting your kitty from these critters is learning what they are, where they come from and what symptoms they cause.

Here’s everything you need to know about the three most common parasites in cats.

#1: Fleas and ticks

Fleas and ticks are the most common external parasites in cats. This means they attach to the cat’s skin or coat. Fleas are barely visible to the eye, growing no more than 2.5 millimeters long. They can be black or reddish-brown in color, and while they don’t have wings, fleas can jump long distances.

Adult ticks are slightly larger than fleas, with an average length of a quarter inch. They have eight legs like spiders and appear red or brown.

These external parasites are more prevalent among outdoor cats. They can pick up fleas by wandering through wooded areas or coming into contact with an infected animal. Ticks find a host by waiting on the tips of long grass. When a cat brushes past, the tick latches onto their skin.

Since fleas and ticks are external parasites, the primary symptom to look for is skin irritation. Fleas, in particular, like to gather on the back of the cat’s neck and base of the tail. Ticks can be anywhere on the body. Contact your vet if you notice excessive grooming, biting or scratching in targeted areas. Cats with external parasites might also show red, inflamed skin, hair loss or secondary skin infections.

The best way to avoid external parasites is by placing your kitty on a flea and tick treatment plan. Cats need year-round protection because fleas can live for months in the right conditions. Consider limiting the amount of time your cat spends outside. When they return indoors, check their coat for any pesky critters they might have picked up along the way.

#2: Tapeworms

Tapeworms are an internal parasite, specifically in the gastrointestinal tract. They’re long and flat, with an average adult length of a quarter inch. Tapeworms infect cats by latching onto the intestinal lining. The cat’s digestive tract becomes irritated when tapeworms bite and feed on their blood.

Similar to fleas and ticks, outdoor cats are more at risk for tapeworms. Cats contract tapeworms by eating infected rodents or birds. Tapeworms can also enter the digestive system when cats groom their paws. Fleas are intermittent carriers of tapeworm eggs, so a flea infestation could lead to this internal parasite.

Since tapeworms live in the gastrointestinal tract, cats with this parasite suffer from digestive problems. Your kitty might lose weight despite eating larger portions. Since tapeworms draw blood, cats with this parasite might develop anemia. Tapeworms cause vomiting and diarrhea, and you might see tiny white pieces that look like rice in their feces.

To avoid tapeworms, consult your vet about a worm treatment plan. This will prevent the intermittent carrier from latching onto your cat’s skin. If your kitty spends lots of time outdoors, make sure the yard is clear of dead rodents or birds. Wipe the cat’s paws when they come inside to get rid of contaminants.

#3: Hookworms

Hookworms are similar to tapeworms because they’re also internal parasites that live in the gastrointestinal tract. However, hookworms are a bit longer, with a maximum length of one inch. They also feed on a cat’s blood by latching onto the intestinal lining.

Much like other intestinal parasites, cats contract hookworms by eating infected wildlife or licking their paws after being outside. Your cat may pick up hookworm larvae by coming into contact with an infected cat’s fecal matter. Hookworms are different from tapeworms because they can also enter through the skin, especially via the paw pads.

Hookworms and tapeworms share many symptoms, which include vomiting, diarrhea, weight loss and anemia. Although hookworms are an internal parasite, they can irritate the skin upon entering the cat’s body. Pet parents might notice eczema, skin lesions or secondary infections on the paw pads or other areas on the skin.

Prevention is almost the same as it is for tapeworms. However, a flea and tick treatment plan won’t protect your kitty from hookworms because fleas don’t carry their eggs. Check for dead animals, wipe their paws and limit time outdoors.

No pet parent likes to think their kitty will become the next target of parasites. For many, reality doesn’t sink in until they’re faced with a sick cat. Play it on the safe side and start protecting your cat from parasites right away. Although several parasites are common, they’re easily preventable through medicine and healthy habits.