Parasitic disease

Parasitic disease refers to an infectious disease caused or transmitted by a parasite. Many parasites do not cause diseases. Parasitic diseases can affect practically all living organisms, including plants and mammals. The study of parasitic diseases is called parasitology.

Types of Parasites

There are three main types of parasites that can cause disease in humans: protozoa, helminths, and ectoparasites.

Protozoa

Protozoa are microscopic, one-celled organisms that can be free-living or parasitic in nature. They are able to multiply in humans, which contributes to their survival and also permits serious infections to develop from just a single organism. Transmission of protozoa that live in a human's intestine to another individual typically occurs through a fecal-oral route (for example, contaminated food or water or person-to-person contact). Protozoa that live in the blood or tissue of humans are transmitted to other humans by an arthropod vector (for example, through the bite of a mosquito or sand fly).

Helminths

Helminths are large, multicellular organisms that are generally visible to the naked eye in their adult stages. Like protozoa, helminths can be either free-living or parasitic. Helminths are unable to multiply in humans.

Ectoparasites

Ectoparasites are organisms that live on the skin but not within the body. Ectoparasites include ticks, fleas, lice, and mites. They are capable of causing disease in humans through infestation of the skin and direct feeding on the blood.

Diagnosis and Treatment

Diagnosis of parasitic diseases depends on the type of parasite. For protozoa and helminths, this often involves examination of stool samples for evidence of the parasites, such as eggs or cysts. For ectoparasites, diagnosis can usually be made based on the clinical presentation of the disease and the patient's history of exposure.

Treatment of parasitic diseases also varies depending on the type of parasite. For protozoa, treatment options include medications such as metronidazole or tinidazole. For helminths, treatment often involves antihelminthic drugs such as mebendazole or albendazole. For ectoparasites, treatment may involve topical creams or lotions, or in some cases oral medications.

Prevention

Prevention of parasitic diseases primarily involves good personal hygiene, safe food and water practices, and use of preventive measures when in areas with a high prevalence of parasites. Template:Infectious diseases Template:Parasitology-stub