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Foot-and-mouth disease

Table of contents
Foot-and-mouth disease
Diagnosis

Foot-and-mouth disease — the acute anthropozoonotic viral infection which is characterized by the cyclic course, fever and formation of specific defeats on mucous membranes of an oral cavity, lips, a nose in interdigital folds and at a nail bed.

Etiology. The activator — the filtered virus possessing the high virulence expressed by a dermotropnost and very high variability. Now according to the international nomenclature allocate 7 independent types of a virus of a foot-and-mouth disease: O, A, C, SAT-1, SAT-2, SAT-3, Asia-1. They differ on serological and immunological properties. Each serological type has the options. 59 options of different serotypes of a virus of a foot-and-mouth disease are known. The virus is highly steady in external environment, well transfers as drying (for example, in milk powder), and freezing. Heating at 80 °C within 30 min. or boiling within 3 — 5 min. kills a virus. From disinfecting solutions 1 — 2% solutions of formaldehyde, 2% solution of caustic natron are most active.

Epidemiology. A foot-and-mouth disease — a high-contagious "rylno-hoofed" disease of cattle. It is widespread on all continents. Epizootological big flashes, especially among cattle are characteristic. An epizooty extends with exclusive speed, covering considerable territories. The disease of people of a foot-and-mouth disease is closely connected with an epizooty, however the susceptibility of the person to it is rather small. In the period of an epizooty at people single diseases are registered, is more often at children. From the person the foot-and-mouth disease is not transmitted to the person. Infection of people comes more often in the alimentary way through not disinfected milks and dairy products, from sick cattle and meat by force of the slaughtered animals. Incidence can have professional character at milkmaids, shepherds, employees of the meat-processing plants and slaughters, veterinary workers catching in the contact way.

Pathogeny. A foot-and-mouth disease virus, getting to a human body through the alimentary system or skin, gets through defects of an epithelium, is localized and breeds. On site primary implementation (more often it is an oral cavity) inflammatory reaction — primary affect develops. Cells of an epithelium form vacuoles which turn into bubbles and at the degeneration phenomena — into bubbles — vesicles. With development of primary vesicles rich with exudate which contains a huge number of a virus the activator gets into blood and extends on all organism. Dissimination of a virus is followed by a hyperthermia and some other all-infectious symptoms. In the period of a virusemia there are secondary vesicles.

Clinic. The incubation interval lasts from 1 to 5 days, is more rare — 7 — 10 days. Usually the disease begins suddenly, with the phenomena of the general intoxication: a fever, temperature increase to 38 — 40 °C, a headache, weakness. Later 1 — 2 day there are a dryness and burning in a mouth, sometimes gripes at an urination. At survey of an oral cavity the bright hyperemia and considerable puffiness of mucous membranes, especially cheeks, language, a soft palate, handles, lips is noted. Against sharply hyperemic and edematous mucous membrane of an oral cavity there are small oval vesicles which can merge in the large bubbles filled in the beginning with transparent, and then muddy contents. In 2 — 3 days of a vesicle are opened, forming superficial erosion (afta). Chewing is complicated. Language increases in sizes, the plentiful sialosis appears. There are painful regional lymph nodes. Vesicles can arise on a mucous membrane of a nose, a vagina, an urethra, on a conjunctiva, and also on face skin, forearms, brushes, shins and feet. Diagnostic value gets rash in interdigital folds and in trailer phalanxes of fingers of hands and legs. Erosion on mucous membranes heal quickly, without leaving behind hems. Skin vesicles are opened also quickly and in 1 — 2 day are epithelized. Gemogramma at the height of a disease is characterized by an eosinophilia, at part of patients — a leukopenia. In cases of an uncomplicated current the feverish period proceeds on average 6 — 8 days. There comes the reconvalescence period. The disease proceeds though is painful, but is benign and 2 — 3 weeks last. In some cases recovery can drag on in connection with repeated rashes with the same evolution of bubbles. At children the infection proceeds in the form of typical stomatitis, conjunctivitis with vesicular rashes on a face. In the period of an epizooty along with clinically expressed the erased disease forms are registered.

There is no uniform clinical classification of a foot-and-mouth disease. Some authors allocate the skin form more often observed at professional infection; mucous at which the main symptom of an illness is aphthous stomatitis; skin and mucous, the most often met of which damage of mucous membranes of an oral cavity and eyes, and also skin mainly in fingers is characteristic. Distinguish also acute forms of various weight proceeding most typically; the erased, easily proceeding forms, long forms of a foot-and-mouth disease at the person. After an illness there is a durable immunity.



 
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