Basics of parasitology 1. Parasite and host relationship Parasiteare organisms that live by living (taking food and other necessities) from other living creatures. The organism that hosts or supports the parasite is calledhostsorhostor host. Parasitismis a reciprocal relationship between one organism and another organism for its survival, where one organism is harmed by another organism. Medical parasitology is the study ofall parasitic organismsin humans. Parasites included in medical parasitology are protozoa, worms and several arthropods. According to where they live in the human body, parasites are divided into endoparasites and ectoparasites. 1.Endoparasites are parasites that live in the human body, for example: in the blood, muscles and intestines, for examplePlasmodiumsp. 2.Ectoparasites is a parasite that lives attached to the outside of the skin and sometimes enters the tissue under the skin, for exampleSarcoptes scabiei. Meanwhile, according to the level of dependence, parasites are differentiatedbe obligate parasites and facultative parasites. 1.Parasitic obligateis a parasite that cannot live if it does not ride on a host, for examplePlasmodiumspp. 2.Parasitic facultativeis a parasite that under certain circumstances can live alone in nature, not riding on a host, for exampleStrongyloides stercoralis. 3.Parasites are not permanentis a parasite whose life moves from one host to another. Examples: mosquitoes, bedbugs. According to the degree of parasitism, parasites are divided into: • Commensalismis a relationship in which an organism benefits from another organism but the organism is not harmed. • Mutualismis a relationship between two types of organisms that both benefit. • Symbiosisis a permanent connection between two organisms and cannot exist separately. • Predator(predator) is a parasite that first kills its prey and then eats it. Most parasites that live in the host's body do not cause disease (non-pathogenic parasites), but in medical parasitology we will focus on parasites (pathogens) that cause disease in humans. The host (host) is where the parasite lives. There are several types of hosts, including: a.The definitive hostnamely the host where the living parasite grows to maturity and reproduces sexually. b.Intermediate hostis where the parasite grows into an infective form that is ready to be exchanged to the host (human). c.Reservoir hostsare animals that contain parasites that become Most parasites that live in the host's body do not cause disease (non-pathogenic parasites), but in medical parasitology we will focus on parasites (pathogens) that cause disease in humans. The host (host) is where the parasite lives. There are several types of hosts, including: a.The definitive hostnamely the host where the living parasite grows to maturity and reproduces sexually. b.Intermediate hostis where the parasite grows into an infective form that is ready to be exchanged to the host (human). c.Reservoir hostsare animals that contain parasites that become source of infection for humans. d.Paratenic hostis an animal that contains the infective stage of the parasite, and this infective stage can be transmitted to an adult in the definitive host. The parasite's relationship with the host and causing disease symptoms is calledinfection. Diseases caused by parasites are calledparasitosis. Vectors are species (generally insects) that can transmit parasites to humans and animals.