What are the two most common endoparasites in animals?

It's difficult to pinpoint the *absolute* most common endoparasites in animals because prevalence varies widely depending on the animal species, geographic location, and other factors. However, two very common and impactful endoparasites include:

1. Roundworms (Nematodes): These are incredibly widespread, infecting a vast array of animals, including humans. Some common examples include:

* Ascarids: Large intestinal roundworms that can cause significant problems in livestock and humans.

* Heartworms: Serious parasites of dogs and other mammals, residing in the heart and lungs.

* Hookworms: Common in dogs, cats, and humans, causing blood loss and anemia.

2. Protozoa: These single-celled eukaryotic organisms can cause a wide range of diseases. Some prominent examples include:

* Coccidia: A group of protozoa that infect the digestive tract of various animals, causing diarrhea and dehydration.

* Giardia: A common intestinal parasite in both humans and animals, causing giardiasis.

* Toxoplasma gondii: A widespread parasite that can cause serious illness in humans, especially pregnant women and people with compromised immune systems.

It's important to note that this list is not exhaustive. There are many other common endoparasites, including tapeworms, flukes, and other protozoa, depending on the specific animal species being considered.