Parasitic Diseases Transmission and Diagnosis

Parasitology

• Parasitology is the study of parasites and parasitic diseases, including methods for diagnosing and identifying parasites.
• A parasite is a living organism that acquires some of its basic nutritional requirements through its intimate contact with another living organism.
• Parasites are eukaryotes, having a well-defined chromosome in a nuclear membrane.

Types of Symbiosis

• Mutualism: reciprocal benefit between two organisms.
• Commensalism: one organism benefits, the other organism is neither benefited nor harmed.
• Parasitism: one organism benefits, the other organism is harmed.

Types of Parasites

• Endoparasite: a parasite that lives within another living organism (e.g., Plasmodium, Giardia).
• Ectoparasite: a parasite that lives on the external surface of another living organism (e.g., lice, ticks).
• Obligate parasite: an organism that cannot survive in any other manner (e.g., Plasmodium).
• Facultative parasite: an organism that may exist in a free-living state or as a commensal, becoming parasitic in suitable conditions (e.g., Naegleria fowleri).
• Accidental parasite: when a parasite attacks an unnatural host and survives (e.g., Hymenolepis diminuta, rat tapeworm).
• Intermittent parasite: arthropods that periodically feed on larger organisms (e.g., mosquitoes).

Host and Parasite Relationships

• Host: the organism where the parasite lives and causes harm.
• Definitive host: the host in which the sexual or adult form of parasite is found.
• Intermediate host: the host in which the asexual or immature, or larval form of the parasite is found.
• Patient: a person who has parasites in their body and shows clinical symptoms.
• Carrier: a person who has parasites in their body but does not show symptoms.
• Reservoir host: an animal that harbors the same species of parasites as humans, potentially transmitting them to humans.

Parasite Classification

• Non-pathogenic parasites: live in/on the body of the host and do not cause disease.
• Pathogenic parasites: disease-causing parasites.
• Opportunistic parasites: do not generally produce disease in healthy individuals but cause illness in individuals with impaired immunity.

Transmission and Infection

• Vector-borne transmission: transmission through vectors like mosquitoes.
• Human-to-human transmission: transmission from one human to another.
• Animal-to-human transmission: transmission from an animal to a human.
• Food-borne transmission: transmission through contaminated food.
• Water-borne transmission: transmission through contaminated water.
• Blood-borne transmission: transmission through contaminated blood.
• Sexual transmission: transmission through sexual contact.
• Congenital transmission: transmission from an infected mother to her baby during pregnancy.
• Infection: the presence of a parasite in or on the tissues of the host.
• Infestation: the presence of arthropods on the skin of the host.