Protozoan Health Dictionary

A zoonotic disease caused by the apicomplexan protozoan Toxoplasma gondii. The definitive hosts of this parasite species are felids (cats).... toxoplasmosis

A disease of the duodenum and small intestine caused by the protozoan, Giardia lamblia. Acquired from contaminated drinking water. Common in children. Sometimes associated with ME (chronic fatigue syndrome).

Symptoms. Explosive diarrhoea, flatulence, abdominal pain, pale fatty stools.

Treatment. Cup Fenugreek tea into which has been added 5-10 drops Tincture Goldenseal. 1 cup thrice daily. ... giardiasis

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

Dum-dum fever. Kala-Azar. Delhi-boil. Oriental sore; a tropical infectious disease caused by protozoan parasites (usually caused by sandflies) manifesting as influenza with (1) internal visceral disturbance, or (2) skin eruptions with ulcerated nose and throat. Often a disease of Mediterranean infants. The case should be seen by a tropical diseases specialist. Until he arrives: decoction Barberry (Berberis vul); half an ounce to 1 pint warm water; steep 20 minutes. 1 cup or more every 2 hours.

Alternatives. Powders. Formula. Echinacea 2; Blue Flag 1; Senna leaf 1. Dose: 500mg (two 00 capsules or one-third teaspoon), every 3 hours.

Liquid Extracts. Formula. Echinacea 2; Burdock 1; Senna leaf 1. Dose: 30-60 drops in water or honey every 3 hours.

Tinctures. Formula. Echinacea 2; Myrrh 1; Goldenseal 1. Dose: one 5ml teaspoon every 3 hours.

Topical. Cleanse skin with washes or lotions of Aloe Vera, Comfrey, Marshmallow, Plantain, Witch Hazel, etc. Treat bite immediately. Do not walk in the bush at dusk. Always take insect repellent and antiseptic cream. ... leishmaniasis

An intestinal infection, causing diarrhoea (often with blood, pus, and mucus) and abdominal pain. There are 2 distinct forms: shigellosis, due to shigella bacteria; and amoebic dysentery, caused by the protozoan parasite

ENTAMOEBA HISTOLYTICA. The main risk with dysentery is dehydration.... dysentery

A serious infectious disease of tropical Africa caused by the protozoan parasite TRYPANOSOMA BRUCEI, which is transmitted to humans by the bites of tsetse flies.

One form of the disease, which occurs in West and Central Africa, takes a slow course, with bouts of fever and lymph node enlargement. After months or years, spread to the brain occurs, causing headaches, confusion, and, eventually, severe lassitude. Without treatment, coma and death follow. The other, East African, form runs a faster course. Fever develops after a few weeks of infection, and effects on the heart may be fatal before the disease has spread to the brain.

Drugs can effect a cure, but there may be residual brain damage if the infection has already spread to the brain.... sleeping sickness

An infection caused by the protozoan TRICHOMONAS VAGINALIS. Trichomoniasis is a common cause of vaginitis. In some cases, the infection is sexually transmitted.

In women, the causative organism may inhabit the vagina for years without causing symptoms. If symptoms occur, they include painful inflammation of the vagina and vulva, and a greenish, frothy, offensive-smelling discharge. Men usually have no symptoms.

The diagnosis is made from examination of a sample of the discharge. Diagnosis usually difficult in men. Treatment is with metronidazole. The sexual partner or partners of an infected person should be treated at the same time to prevent reinfection.... trichomoniasis

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)

ACUTE LIVER DISEASE The hepatitis viruses (A– F) are of paramount importance. Hepatitis E (HEV) often produces acute hepatic failure in pregnant women; extensive epidemics – transmitted by contaminated drinking-water supplies – have been documented. HBV, especially in association with HDV, also causes acute liver failure in infected patients in several tropical countries: however, the major importance of HBV is that the infection leads to chronic liver disease (see below). Other hepatotoxic viruses include the EPSTEIN BARR VIRUS, CYTOMEGALOVIRUS (CMV), the ?avivirus causing YELLOW FEVER, Marburg/Ebola viruses, etc. Acute liver disease also occurs in the presence of several acute bacterial infections, including Salmonella typhi, brucellosis, leptospirosis, syphilis, etc. The complex type of jaundice associated with acute systemic bacterial infection – especially pneumococcal PNEUMONIA and pyomiositis – assumes a major importance in many tropical countries, especially those in Africa and in Papua New Guinea. Of protozoan infections, plasmodium falciparum malaria, LEISHMANIASIS, and TOXOPLASMOSIS should be considered. Ascaris lumbricoides (the roundworm) can produce obstruction to the biliary system. CHRONIC LIVER DISEASE Long-term disease is dominated by sequelae of HBV and HCV infections (often acquired during the neonatal period), both of which can cause chronic active hepatitis, cirrhosis, and hepatocellular carcinoma (‘hepatoma’) – one of the world’s most common malignancies. Chronic liver disease is also caused by SCHISTOSOMIASIS (usually Schistosoma mansoni and S. japonicum), and acute and chronic alcohol ingestion. Furthermore, many local herbal remedies and also orthodox chemotherapeutic compounds (e.g. those used in tuberculosis and leprosy) can result in chronic liver disease. HAEMOSIDEROSIS is a major problem in southern Africa. Hepatocytes contain excessive iron – derived primarily from an excessive intake, often present in locally brewed beer; however, a genetic predisposition seems likely. Indian childhood cirrhosis – associated with an excess of copper – is a major problem in India and surrounding countries. Epidemiological evidence shows that much of the copper is derived from copper vessels used to store milk after weaning. Veno-occlusive disease was ?rst described in Jamaica and is caused by pyrrolyzidine alkaloids (present in bush-tea). Several HIV-associated ‘opportunistic’ infections can give rise to hepatic disease (see AIDS/HIV).

A localised (focal) form of liver disease in all tropical/subtropical countries results from invasive Entamoeba histolytica infection (amoebic liver ‘abscess’); serology and imaging techniques assist in diagnosis. Hydatidosis also causes localised liver disease; one or more cysts usually involve the right lobe of the liver. Serological tests and imaging techniques are of value in diagnosis. Whilst surgery formerly constituted the sole method of management, prolonged courses of albendazole and/or praziquantel have now been shown to be e?ective; however, surgical intervention is still required in some cases.

Hepato-biliary disease is also a problem in many tropical/subtropical countries. In southeast Asia, Clonorchis sinensis and Opisthorchis viverini infections cause chronic biliary-tract infection, complicated by adenocarcinoma of the biliary system. Praziquantel is e?ective chemotherapy before advanced disease ensues. Fasciola hepatica (the liver ?uke) is a further hepato-biliary helminthic infection; treatment is with bithionol or triclabendazole, praziquantel being relatively ine?ective.... liver disease in the tropics

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

Various parasites and infectious organisms can spread from cats to humans. The most serious disease is rabies. Cat-scratch fever is an uncommon illness caused by infection with the bacterium ROCHALIMAEA HENDELAE following a cat scratch or bite. Cats commonly carry the protozoan TOXOPLASMA GONDII, which causes toxoplasmosis.

Infection, usually from contact with cat’s faeces, is not generally serious but has serious consequences if a woman is infected during pregnancy.

Cat faeces may also carry eggs of the cat roundworm, a possible cause of toxocariasis.

Rarely, a larva from an ingested roundworm egg migrates to and lodges in an eye, causing deterioration of vision or even blindness.

Children who have been playing in sand or soil contaminated by cat faeces are most commonly affected.

Other cat-related disorders in humans include tinea (ringworm), fungal infections of the skin, bites from cat fleas, and allergic reactions to dander that may cause asthma or urticaria.

Diseases from cats can be avoided by good hygiene, veterinary care for animals that are ill, and regular worming and flea treatment of cats.... cats, diseases from

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