Protozoan: From 1 Different Sources
n. a microorganism of the group *protozoa.
A zoonotic disease caused by the apicomplexan protozoan Toxoplasma gondii. The definitive hosts of this parasite species are felids (cats).... toxoplasmosis
A minute protozoan organism consisting of a single cell, in which a nucleus is surrounded by protoplasm that changes its shape as the protozoon progresses or absorbs nourishment. Several varieties are found under di?erent conditions within the human body. One variety, Entamoeba coli, is found in the large intestine of humans without any associated disease; another, Entamoeba gingivalis, is found in the sockets of the teeth and associated with PYORRHOEA. Entamoeba histolytica is the causative organism of amoebic dysentery (see DYSENTERY); Acanthamoeba and Naegleria fowleri cause the infection of the brain known as MENINGOENCEPHALITIS. Entamoeba histolytica may also cause meningoencephalitis. Other forms are found in the genital organs.... amoeba
A zoonotic protozoan disease endemic to parts of Latin America and caused by Trypanosmoma cruzi with reduviid (Triatomid or assassin) bugs as the vectors.... chagas’ disease
An antibiotic used widely for anaerobic bacterial infections (including pseudomembranous colitis) and also for such protozoan infections as giardiasis, trichmoniasis and amoebiasis.... metronidazole
A ciliate protozoan of pigs which can infect humans causing balantidial dysentery.... balantidium coli
Apicomplexan protozoan associated with a watery diarrhoea in children and immunocompromised adults. Zoonotic infection often contracted from contaminated water. Commonest species in humans is Cryptosporidium parvum..... cryptosporidium
A spectrum of skin disease caused by protozoan Leishmania spp, with a lifecycle and vectors identical to that of Leishmania donovani (see visceral leishmaniasis). The spectrum of disease ranges from a single, dry cutaneous lesion (L. tropica) through to destructive mucocutaneous lesions (L. braziliensis braziliensis).... cutaneous leishmaniasis
Initially believed to be a blue -green alga now known to be an apicomplexan protozoan. Can cause diarrhoea in humans.... cyclosporidium cayetanensis
Delhi boil is a form of chronic body sore occurring in Eastern countries, caused by a protozoan parasite, Leishmania tropica. (See LEISHMANIASIS.)... delhi boil
An intestinal flagellate protozoan of humans. May be associated with a mild diarrhoea.... dientamoeba fragilis
Discharge of mucus from the VAGINA. It may be whitish or yellowish and is normal in some women, usually increasing before and after MENSTRUATION. It is distinct from abnormal discharges with an o?ensive smell and yellow or green colouring: these may be caused by micro-organisms or by fungal infection such as Candida albicans. Another causative agent is the protozoan parasite, Trichomonas vaginalis (see TRICHOMONIASIS). A pessary or tampon that a woman has forgotten to remove will cause a substantial and o?ensive discharge. Children rarely have vaginal discharge; if they do, it is usually due to an infection or foreign body in the vagina. (See also UTERUS, DISEASES OF.)... leucorrhoea
A protozoan disease of humans caused by blood parasites of the species, Plasmodium falciparum, P. vivax, P. ovale or P. malariae and transmitted by anopheline mosquitoes. P. falciparum is most likely to cause death, if untreated,. and can also be a great mimicker in its presentation. Malaria should be suspected in anyone with a fever or who is otherwise unwell and has returned from a malarious area.... malaria
A fungus, formally believed to be a protozoan, which may cause an atypical pneumonia in severely malnourished or immunologically compromised patients, e.g. AIDS patients.... pneumocystis carinii
Diarrhoea frequently recorded from travellers, especially those visiting tropical or developing regions of the world. Probably the commonest travel-related infection. Although it can be caused by a range of viral, bacterial, protozoan and even on occasions, fungal and helminthic agents, in excess of 80-90% of cases are due to enterotoxigenic Escherichia coli (ETEC) or less commonly enteroadherent Esch. coli (E.Ad.EC).... travellers’ diarrhoea
The motile, feeding stage of protozoan parasites.... trophozoites
A protozoan disease caused by Leishmania donovani, found around parts of the Mediterranean basin, tropical Africa, South America, and central and eastern Asia. The disease is transmitted byfemale sandflies of the genus, Phlebotomus in the Old World and Lutzomyia in the New World. Full-blown disease is often fatal, if untreated. Growth nodules of the disease or leishmanioma form initially and, if spontaneous recoverydoes not occur, proliferating parasites burst out of the nodules, disseminating throughout the body.... visceral leishmaniasis (kala azar)
The most severe form of malaria, caused by the parasitic protozoan PLASMODIUM FALCIPARUM.... falciparum malaria
n. an infestation of the large intestine with the parasitic protozoan *Balantidium coli. Humans usually become infected by ingesting food or drink contaminated with cysts from the faeces of a pig. The parasite invades and destroys the intestinal wall, causing ulceration and *necrosis, and the patient may experience diarrhoea and dysentery. Balantidiasis is a rare cause of dysentery, mainly affecting farm workers; it is treated with various antibiotics.... balantidiasis
n. a genus of one of the largest parasitic *protozoans affecting humans (70 ?m or more in length). The oval body is covered with threadlike cilia (for locomotion). B. coli, normally living in the gut of pigs as a harmless *commensal, occasionally infects humans (see balantidiasis).... balantidium
(mucocutaneous leishmaniasis) n. a disease of the skin and mucous membranes caused by the parasitic protozoan Leishmania braziliensis (see leishmaniasis). Occurring in South and Central America, espundia takes the form of ulcerating lesions on the arms and legs; the infection may also spread to the mucous membranes of the nose and mouth, causing serious destruction of the tissues.... espundia
n. inflammation of the colon due to infection, inflammation, or ischaemia. It is diagnosed by clinical assessment combined with radiological imaging, stool cultures, and endoscopic evaluation. Infectious colitis may be due to viruses, bacteria, or protozoans (for example, *Entamoeba histolytica causes amoebic colitis: see dysentery). Inflammatory colitis encompasses *Crohn’s disease (Crohn’s colitis), *ulcerative colitis, and microscopic colitis. Microscopic colitis can only be seen under a microscope (at endoscopy the colon appears normal). Symptoms of inflammatory colitis may include diarrhoea, abdominal pain, and the passage of blood and mucus in the stools. Ischaemic colitis occurs when there is partial or complete cessation of the blood supply to a particular region of the colon.... colitis
n. 1. an abnormal sac or closed cavity lined with *epithelium and filled with liquid or semisolid matter. There are many varieties of cysts occurring in different parts of the body. Retention cysts arise when the outlet of a glandular duct is blocked, as in *sebaceous cysts. Some cysts are congenital, due to abnormal embryonic development; for example, *dermoid cysts. Others are tumours containing cells that secrete mucus or other substances, and another type of cyst is formed by parasites in the body (see hydatid). Cysts may occur in the jaws: a periapical cyst occurs at the apex of a tooth, a dentigerous cyst occurs around the crown of an unerupted tooth, and an eruption cyst forms over an erupting tooth. See also fimbrial cyst; ovarian cyst; pseudocyst. 2. a dormant stage produced during the life cycle of certain protozoan parasites of the alimentary canal, including *Giardia and *Entamoeba. Cysts, passed out in the faeces, have tough outer coats that protect the parasites from unfavourable conditions. The parasites emerge from their cysts when they are eaten by a new host. 3. a structure formed by and surrounding the larvae of certain parasitic worms.... cyst
n. a small light-sensitive area of pigment found in some protozoans and other lower organisms.... eyespot
n. a method of asexual reproduction in which the body of a protozoan or bacterium splits into two equal parts (binary fission), as in the *amoebae, or more than two equal parts (multiple fission), for example sporozoite formation in the malarial parasite (see Plasmodium). The resulting products of fission eventually grow into complete organisms.... fission
n. a type of *protozoan with one or more fine whiplike threads (see flagellum) projecting from its body surface, by means of which it is able to swim. Some flagellates are parasites of humans and are therefore of medical importance. See Trypanosoma; Leishmania; Giardia; Trichomonas.... flagellate
(visceral leishmaniasis, Dumdum fever) n. a tropical disease caused by the parasitic protozoan *Leishmania donovani. The parasite, which is transmitted to humans by *sandflies, invades the cells of the lymphatic system, spleen, and bone marrow. Symptoms include enlargement and subsequent lesions of the liver and spleen; anaemia; a low *leucocyte count; weight loss; and irregular fevers. The disease occurs in Asia, South America, the Mediterranean area, and Africa. Drugs containing antimony, with supplementary pentamidine, are used in the treatment of this potentially fatal disease.... kala-azar
n. a genus of parasitic flagellate protozoans, several species of which cause disease in humans (see leishmaniasis). The parasite assumes a different form in each of its two hosts. In humans, especially in *kala-azar patients, it is a small rounded structure, with no flagellum, called a Leishman–Donovan body, which is found within the cells of the lymphatic system, spleen, and bone marrow. In the insect carrier it is long and flagellated.... leishmania
n. the nonmotile female sex cell of the malarial parasite (Plasmodium) and other protozoans. The macrogamete is similar to the ovum of animals and larger than the male sex cell (see microgamete).... macrogamete
(gentian violet) a dye used mainly for staining protozoans.... methyl violet
n. the motile flagellate male sex cell of the malarial parasite (Plasmodium) and other protozoans. The microgamete is similar to the sperm cell of animals and smaller than the female sex cell (see macrogamete).... microgamete
(Baghdad boil, Delhi boil, Aleppo boil) a skin disease, occurring in tropical and subtropical Africa and Asia, caused by the parasitic protozoan Leishmania tropica (see leishmaniasis). The disease commonly affects children and takes the form of a slow-healing open sore or ulcer, which sometimes becomes secondarily infected with bacteria. Antibiotics are administered to combat the infection.... oriental sore
n. a drug effective against protozoans and used in the treatment of *Pneumocystis pneumonia in AIDS patients, *leishmaniasis, and trypanosomiasis. Possible side-effects include low blood pressure, heart irregularity, low blood sugar (hypoglycaemia), low white blood cell count, and kidney damage.... pentamidine
n. a genus of protozoans (see Sporozoa) that live as parasites within human red blood cells and liver cells. The parasite undergoes its asexual development (see schizogony) in humans and completes the sexual phase of its development (see sporogony) in the stomach and digestive glands of a bloodsucking *Anopheles mosquito. Four species cause *malaria: P. vivax, P. ovale, P. falciparum, and P. malariae.... plasmodium
n. a genus of protozoans. The species P. jiroveci (formerly carinii) causes pneumonia in immunosuppressed patients, usually following intensive chemotherapy. Pneumocystis jiroveci (carinii) pneumonia (PCP) is fatal in 10–30% of cases if untreated, but it can be overcome with high doses of *co-trimoxazole or *pentamidine.... pneumocystis
n. a genus of parasitic protozoans (see Sporozoa) that infect birds, reptiles, and herbivorous mammals. S. lindemanni, which occasionally infects humans, forms cylindrical cysts (sarcocysts) in the muscle fibres. In heavy infections these cysts can cause tissue degeneration and therefore provoke muscular pain and weakness. Sarcocysts have, in the few positively diagnosed cases, been located in the heart muscles, arm muscles, and larynx.... sarcocystis
n. a phase of asexual reproduction in the life cycle of a sporozoan (protozoan parasite) that occurs in the liver or red blood cells. The parasite grows and divides many times to form a schizont, which contains many *merozoites. The eventual release of merozoites of *Plasmodium, the malaria parasite, from the blood cells produces fever in the patient.... schizogony
n. a group of parasitic protozoans that includes *Plasmodium, the malaria parasite. Most sporozoans do not have cilia or flagella. Sporozoan life cycles are complex and usually involve both sexual and asexual stages. Some sporozoans are parasites of invertebrates, and the parasites are passed to new hosts by means of spores. Sporozoans that parasitize vertebrates are transmitted from host to host by invertebrates, which act as intermediate hosts. For example, the mosquito Anopheles is the intermediate host of Plasmodium.... sporozoa
n. a genus of parasitic flagellate protozoans that move by means of a wavy membrane, bearing a single flagellum, projecting from the body surface. T. vaginalis often infects the vagina, where it may cause severe irritation and a foul-smelling discharge (see vaginitis), and sometimes also the male *urethra; it can be transmitted during sexual intercourse. T. hominis and T. tenax live in the large intestine and mouth respectively. See also trichomoniasis.... trichomonas
n. a genus of parasitic protozoans that move by means of a long trailing flagellum and a thin wavy membrane, which project from the body surface. Trypanosomes undergo part of their development in the blood of a vertebrate host. The remaining stages occur in invertebrate hosts, which then transmit the parasites back to the vertebrates. T. rhodesiense and T. gambiense, which are transmitted through the bite of *tsetse flies, cause *sleeping sickness in Africa. T. cruzi, carried by *reduviid bugs, causes Chagas’ disease in South America.... trypanosoma
n. any disease caused by the presence of parasitic protozoans of the genus *Trypanosoma. The two most important diseases are *Chagas’ disease (South American trypanosomiasis) and *sleeping sickness (African trypanosomiasis).... trypanosomiasis
adj. describing organisms or tissues that consist of a single cell. Unicellular organisms include the protozoans, most bacteria, and some fungi.... unicellular
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