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Miyaz: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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Miasis - invasion by larvae of some species of flies and gadflies; characterized by polymorphism of symptoms depending on the localization of the parasite.
ICD-10 codes
- B87. Miyaz.
- B87.0. Cutaneous miass.
- B87.1. Wound miasis.
- B87.2. The eye mias.
- B87.3. Nasopharyngeal miasis.
- B87.4. Miaze of the ear.
- B87.8. Miaz of other localizations. Miasis of the genitourinary, intestinal miass.
- B87.9. Miaz unspecified.
Epidemiology of the miase
Larvae of nonparasitic flies cause random miases. They also develop with the use of food products containing larvae of flies (intestinal mias), when laying eggs on linen in contact with the body, and penetration of larvae into the urethra (urogenital miase), conjunctival sac (eye miases), through the ear, mouth, nose cavitary miass).
Facultative miases are caused by larvae of non-parasitic species of flies, which live in corpses, manure, rotting plants. The disease occurs when flies of eggs are laid in wounds, ulcers, nasal passages and external auditory meatus if there is an inflammatory process in them.
Obligate miases are caused by larvae of parasitic species of flies and gadflies that live in human tissues and warm-blooded animals. The disease occurs when the larvae of flies (wolfar flies) are introduced and the gadflies in the epidermis or laying the eggs of the cavity gadfly in the eyes and the nostrils together with the liquid that the female injects on the fly.
[What causes a miasis?
Miaz is caused by the insect larvae of the order Diptera , flies and flies. In humans, parasitizers of obligate miases are most often infected : Wolhfahrtia magnifica larvae, Hypoderma gadflyfly and Gastrophilus flies of Cordylobia anthropophaga (causative agent of cordillobiosis), Dermatobia hominis (causative agent of dermatobiosis), ovine oestrus Oestrus ovis and horse gadfly Rhinoestrus purpureas. Random and facultative miases are caused by larvae of nonparasitic species of flies: room - Musca domestica, house - Muscina stabulans, small room - Fannia canicularis, as well as blue and green meat and cheese.
The larvae are stable in the environment, able to survive in sewage waters, some are resistant to the action of disinfectants. Flies lay eggs at a temperature of 16-40 ° C, the larvae develop from 18 days
at 16 ° C to 3 days at 36 ° C.
Pathogenesis of the miase
The pathogenesis of the miase is caused by the localization of the larva, which causes mechanical damage and inflammation, which destroys its tissues with the development of necrosis, as well as the toxic and allergic action of metabolites.
Symptoms of the miase
Localization distinguishes between skin (tissue), cavity, urogenital, eye and intestinal miase. The intestinal miasis is acute, with abdominal pain, vomiting, diarrhea, fever. For the urogenital miase, the following symptoms of the mias are characteristic: cutting pain and delayed urination.
With wound miase, a complicated course in the form of a suppuration process is possible.
With an obligate benign miase, the larvae (usually the gadflies) migrate to the subcutaneous tissue, spreading throughout the body. At the same time, itchy skin, the appearance in it of the migrating larvae of the passages, which resemble healing scratches, are recorded. After molting the larvae around it, a capsule forms - an infiltrate appears. A few days later, a fistula is formed, through which the larvae exit. After this, the infiltrate dissolves. Severe conditions are possible with perforation of the larval wall of the intestine or its penetration into the brain. When the larvae enter the eye, conjunctivitis develops, accompanied by cutting pains and lacrimation. The introduction of larvae into the eyeball can lead to blindness. When parasitizing larvae in the nose appears mucopurulent discharge from one half of the nose, there may be a headache, fever.
With malignant miase (causative agent - wolfar flies larvae), larvae penetrate through the damaged skin and mucous membranes into the underlying tissue, causing inflammation in them, causing the symptoms of the miase: intense pain, fever, intoxication, tissue necrosis. When the larva penetrates the brain, a lethal outcome is possible.
Diagnosis of the miase
Diagnosis of the miase consists in the visual detection of larvae in vomit, wounded, etc., depending on the location of the parasite.
What do need to examine?
Differential diagnosis of the miase
Depending on the location of the larvae, the miase is differentiated from food poisoning, salmonellosis and other acute intestinal infections, urethritis, conjunctivitis, rhinitis of another etiology, phlegmon, invasion by larvae of helminths (Larva Migrans).
Indications for consultation of other specialists
Consultations of the surgeon, urologist, ophthalmologist or neurologist are shown, depending on the localization of the parasite.
Treatment of miase
Treatment of miase depends on the form:
- With intestinal miase - gastric lavage, the appointment of a laxative.
- With urogenital miase - washing the urethra with antiseptics; removal of larvae from the skin of wounds.
- With tissue necrosis, surgical treatment of the miase.
Clinical examination
Dispensary observation of those who have recovered is not shown.
How to prevent a miasis?
Prevent miase can be, provided that the improvement of populated areas and the control of flies (in livestock areas - with the gadflies), protecting food from them. Prevention of wounds, skin and mucous membrane damage from flies (gadflies).