Meningoencephalitis Health Dictionary

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 rare disease, although the causal organism, Listeria monocytogenes, is widely distributed in soil, silage, water, and various animals, with consequent risk of food contamination – for example, from unpasteurised soft cheese. Neonates are mainly affected – often as a result of a mild or inapparent infection in the pregnant mother. The disease presents in two main forms: MENINGOENCEPHALITIS, or SEPTICAEMIA with enlarged LYMPH glands. Elderly adults occasionally develop the ?rst form, while younger adults are more likely to develop a mild or even inapparent form. The disease is treated with ANTIBIOTICS such as ampicillin (see PENICILLIN) or CHLORAMPHENICOL.... listeriosis

This infection is caused by nematode worms of the genus Strongyloides spp. – the great majority being from S. stercoralis. This helminth is present throughout most tropical and subtropical countries; a single case report has been made in England – about an individual who had not been exposed to such an environment. Larvae usually penetrate intact skin, especially the feet (as with hookworm infection). Unlike hookworm infection, eggs mature and hatch in the lower gastrointestinal tract; thus larvae can immediately re-enter the circulation in the colo-rectum or perianal region, setting up an auto-infection cycle. Therefore, infection can continue for the remaining lifespan of the individual. Severe malnutrition may be a predisposing factor to infection, as was the case in prisoners of war in south-east Asia during World War II.

Whilst an infected patient is frequently asymptomatic, heavy infection can cause jejunal mucosal abnormalities, and an absorptive defect, with weight loss. During the migratory phase an itchy linear rash (larva currens) may be present on the lower abdomen, buttocks, and groins; this gives rise to recurrent transient itching. In an immunosuppressed individual, the ‘hyperinfection syndrome’ may ensue; migratory larvae invade all organs and tissues, including the lungs and brain. Associated with this widespread infection, the patient may develop an Enterobacteriacae spp. SEPTICAEMIA; this, together with S. stercoralis larvae, produces a MENINGOENCEPHALITIS. There is no evidence that this syndrome is more common in patients with HIV infection.

Diagnosis consists of visualisation of S. stercoralis (larvae or adults) in a jejunal biopsy-section or aspirate. Larvae may also be demonstrable in a faecal sample, especially following culture. Eosinophilia may be present in peripheral blood, during the invasive stage of infection. Chemotherapy consists of albendazole. The formerly used benzimidazole compound, thiabendazole, is now rarely prescribed in an uncomplicated infection due to unpleasant side-effects; even so, in the ‘hyperinfection syndrome’ it probably remains the more e?ective of the two compounds.... strongyloidiasis

n. a genus of Gram-positive aerobic motile rodlike bacteria that are parasites of warm-blooded animals. The single species, L. monocytogenes, infects many domestic and wild animals. If it is transmitted to humans, by eating infected animals or animal products, it may cause disease (listeriosis), especially in the frail, ranging from influenza-like symptoms to meningoencephalitis. In pregnant women it may cause a miscarriage or damage the fetus.... listeria

n. see meningoencephalitis.... meningoencephalomyelitis

n. a genus of *amoebae that normally live in damp soil or mud. Naegleria species can, however, live as parasites in humans: N. fowleri is responsible for primary amoebic *meningoencephalitis, a very rare, but fatal, infection of the brain.... naegleria