Acanthamebiasis illnesses

Acanthamebiasis illnesses - the diseases caused by various kinds of free living amebas, showing mainly in lesions of the central excitatory system and an eye.

Aetiology. An acanthamefe concern the elementary Protozoa, a subtype - Sarcomastigophora, superclass - Sarcodina, group - Amoebida. The bunch of free living amebas includes various kinds (Acantamoeba castellani, A. polyphaga, Naegleriafowleri, etc.). They dwell everywhere in bedrock, water, manure, etc. The dimensions of an ameboid stage 10-30 microns. Cysts 7-17 microns. Cysts it is long remain in an external environment, are pathogenic for some laboratory animals. It is possible to cultivate on nutrient mediums and in culture of a tissue.

Epidemiology. Infestation of the human descends mainly at hit of amebas in a nasopharynx and on a conjunctiva of eyes at bathing to what rising of a case rate during a swimming season testifies (July-August), and also group diseases at bathing in the same reservoir. Less often the becoming infected descends through dirty arms (especially children), and also air-dust by. The carriage acanthamefe healthy humans is possible.

Pathogenesis. Infection atriums is the nose mucosa (at ophthalmic forms - a conjunctiva of eyes), whence an acanthamefe on olfactory nerves inpour into a brain. On a mucosa of a nose in the field of olfactory nerves the inflammation with a superficial ulceration becomes perceptible, here are found only individual an acanthamefe, their number increases in fibers of olfactory nerves which are inflamed and necrotizing. Ventral fields of olfactory bulbs are completely blasted, abundant clumps acanthamefe here are taped. Meninxes are amazed, pathological process is most expressed in a superficial cortical layer of grey matter of the big parencephalons and in basal ganglions. Amebas are found also in a cerebellum, a meningeal exsudate, cerebrospinal fluid. Hematogenically they can be brought in various organs (lungs, nephroses, a liver, lymph nodes, etc.).

Symptoms and flow. The incubation interval proceeds 3-7 days is more often. The Meningoentsefalitichesky form begins subitaneously, appear and quickly signs of an inflammation of the top respiratory tracts (nasopharyngitis) progress, with a fever the body temperature raises. There is a strong headache, a nausea, vomiting, a rigidity of a nucha and other meningeal signs, the encephalitis and a coma educes. The mors comes in 2-7 days after appearance of the first symptoms of illness. Appointment of etiotropic preparations extends life of patients. At patients AIDS and a HIV-infected illness proceeds in the generalised form with a lesion of various organs and formation of abscesses (hypodermic, intramuscular, in lungs, etc.).

Acanthamebiasis lesions of eyes are bound to application of contact lenses, mainly soft. Clinically they show in a kind conjunctivitis. On the foreground signs of a keratitis which is characterised by damage of an epithelium, act as ring infiltration, very long flow, formation of cicatrixes, turbidity of a cornea and necessity for further its transplantation. All process lasts some months. Transition to a brain and infection contamination generalisation at this form it is not observed.

The diagnosis and the differential diagnosis. About acanthamebiasis pathologies it is necessary to think at subitaneously begun serious meningocephalites, and also at appearance of a keratitis (keratoconjunctivitis), especially at the persons using contact lenses. Diagnosis acknowledgement is originator detection. For research take cerebrospinal fluid or biopsy samples of tissues (a brain, lungs, a cornea). Use various methods: direct microscopy, histological research of biopsy samples, abjection of culture of amebas on nutrient mediums, biological tests on mice, a method of an indirect immunofluorescence, etc. to Differentiate it is necessary with serious meningocephalites of other aetiology (a bacteriemic infection contamination, virus meningocephalites, etc.). At keratoconjunctivites also it is necessary to exclude herpetic, adenoviral, traumatic damages of a cornea.