Foot and mouth disease is an acute infectious disease of viral etiology characterized by vesicular erosive lesion of the integumentary tissues (mainly the mucous membranes of the mouth and the skin of the extremities), accompanied by intoxication syndrome. Foot and mouth disease infection occurs from livestock and wild animals mainly by contact, but a food route is also possible. The clinical picture consists of acute conjunctivitis, widespread aphthous stomatitis, general infectious symptoms and lesions of the skin around the mouth, on the wings of the nose, in the interdigital spaces.
ICD 10
B08.8 Other specified infections characterized by lesions of the skin and mucous membranes
General information
Foot and mouth disease (FMD) is an acute infectious disease of viral etiology characterized by vesicular erosive lesion of the integumentary tissues (mainly the mucous membranes of the mouth and the skin of the extremities), accompanied by intoxication syndrome.
Causes
The causative agent of foot and mouth disease is an RNA-containing virus of the genus Aphtovirus. It has high virulence and has affinity with epithelial structures of the skin and mucous membranes. The virus is resistant in the external environment, able to maintain viability on animal fur for up to 4 weeks, up to 3.5 weeks – on clothes. It easily tolerates freezing and drying, is inactivated by heating, UV irradiation, exposure to disinfectant solutions (usually formalin solutions (1%), alkalis (2%), ethylene oxide (1%) are used).
The reservoir and source of foot–and-mouth disease are ungulates – both wild and livestock. Some rodents are susceptible to the foot and mouth disease virus, but they do not take a significant part in the spread of infection. Birds do not get foot and mouth disease, but they can carry the pathogen during migration. The release of the pathogen by sick animals occurs with milk, saliva, feces, urine. A sick person does not pose an epidemiological danger.
Pathogenesis
Foot and mouth disease is transmitted through a contact mechanism, infection occurs when the virus enters the damaged skin or mucous membrane. Infection often occurs when caring for animals, processing hides, wool, and inhaling dust suspension containing viruses. It is possible to implement a food pathway of infection when using properly untreated dairy and meat products from sick animals. Due to the high resistance in the environment, the foot and mouth disease virus can be introduced into areas remote from the foci of infection, affecting farm animals.
The natural susceptibility of people to foot and mouth disease is quite low, after the transfer of the disease, a short (up to one and a half years) type-specific immunity is formed. Foot and mouth disease is mainly an occupational disease, it is common in rural areas and among workers of agricultural livestock enterprises, meat processing plants, persons engaged in slaughtering livestock and processing animal raw materials. Outside of this group, the disease is noted in children after eating contaminated dairy products.
Symptoms
The incubation period of foot and mouth disease can be from 2 to 12 days, on average it lasts 3-4 days. The onset of the disease is acute, often sudden. There is chills and a sharp increase in body temperature, headache, pain in the extremities, lower back. By the end of the first day of the disease, burning in the mouth, hypersalivation are usually noted. There may be a lesion of the urethral mucosa, manifested in the form of sharply painful urination.
Examination of patients reveals irritation and hyperemia of the conjunctiva, enlargement and soreness of regional lymph nodes, oral mucosa is pronounced edematous, hyperemic, covered with small, filled with transparent or cloudy contents, vesicles (aphthae). Aphthae are mainly located at the edges and at the tip of the edematous tongue. A day later, the bubbles are opened, leaving behind erosions that can merge, forming extensive eroded areas (currently, such a prevalence of the erosive process is quite rare).
With a large-scale lesion of the oral mucosa, difficulties arise in speech, swallowing, hypersalivation progresses (up to the expiration of saliva by a jet). The lips of patients are usually swollen, crusts are marked on them, erosions can occur on the skin around the mouth, nose wings, conjunctiva. Also, sometimes there is a skin lesion in the folds between the fingers, near the nails. In some cases, skin manifestations (for example, on the hands) are not accompanied by damage to the oral cavity.
Foot and mouth disease in children is more severe, abdominal symptoms (abdominal pain, dyspeptic disorders, diarrhea) are often noted. Erosions epithelize after 4-5 days, the fever subsides. Full recovery occurs in 10-15 days, but with significant lesions, combined erosions of the skin and mucous membrane, it is sometimes delayed for a month or more. In some cases, the repeated formation of vesicles is noted.
Complications
Foot and mouth disease is complicated quite rarely. The resulting complications are mainly associated with secondary infection. These can be pneumonia, myocarditis, purulent diseases of the skin and mucous membranes, sepsis, etc.
Diagnostics
The pathogen is isolated from scraping from erosions, saliva, feces, however, virological diagnostic methods are not used in mass clinical practice due to the complexity. Serological diagnosis of foot and mouth disease is carried out using HCR and RPH in paired serums (sampling of material at intervals of 7 days). Sometimes a biopsy is performed on guinea pigs (the patient’s separated aft is rubbed into the pads of the animals’ paws).
Treatment
FMD treatment is carried out in a hospital, the main therapeutic measures are aimed at oral care, local treatment, relief of symptoms. At the time of severe lesions of the oral cavity, patients eat semi-liquid, easily digestible food of moderate temperature, which does not contain irritating components. If necessary (extensive lesions), nutrition is carried out through a probe or parenterally.
- Ointments (oxoline, enamel, interferon), physiotherapy techniques (ultraviolet and laser irradiation) are applied topically.
- Symptomatic agents (analgesics, antipyretics, cardiovascular and desensitizing agents) are prescribed according to indications.
- If necessary, detoxification measures are carried out. Vitamins and adaptogens are prescribed for general strengthening purposes.
Prognosis and prevention
The prognosis for foot and mouth disease is usually favorable, in the vast majority of cases the disease ends with recovery, leaving no pathological consequences. Severe foot and mouth disease in young children has a serious prognosis, in some cases ending in death.
The basis of prevention is veterinary control over the health of farm animals, timely routine vaccination (carried out with inactivated FMD vaccines), quarantine measures against sick animals. In addition, sanitary and hygienic control over the health and working conditions of employees of agricultural enterprises is carried out.
Individual prevention consists in observing personal hygiene measures when working with livestock, animal raw materials, protection from injury to the skin. Among other things, it is necessary to consume dairy and meat products that have undergone the necessary processing, in particular, precautions are important when feeding children. Immunization of people is not carried out.
