Final answer:
Internal parasites are organisms such as helminths and protozoa that live inside hosts like humans and animals, causing diseases and health issues. They have complex life cycles and can be transmitted through various means, including undercooked food and contaminated water.
Step-by-step explanation:
Internal parasites are organisms that live inside their host, relying on it for survival; this includes various types of worms such as hookworms, roundworms, and tapeworms. Parasites come in different forms, such as helminths (worm-like parasites) and protozoa, and can cause a range of diseases and health complications for their hosts. For instance, hookworms infect the human intestine, leading to pain and other health issues. Helminths can be categorized into nematodes, cestodes, and trematodes, with each group having different characteristics and effects on the host.
Parasites typically have complex life cycles, often dependent on one or more hosts to complete their development. They can be transmitted via various routes like undercooked food, contaminated water, or through the skin. Worldwide, many parasitic diseases like malaria and trichinosis are caused by these parasites, posing significant medical and public health challenges, particularly in non-industrialized regions.
The Centers for Disease Control and Prevention (CDC) provides up-to-date information on parasitic diseases, showcasing the relevance and importance of understanding and controlling these internal parasites to prevent the spread of related diseases.