Anthrax is an acute, especially dangerous infectious disease that occurs in humans and animals when infected with Bacillus anthracis, occurring with the formation of specific carbuncles on the skin, or in septic form. The source of infection is wild animals and cattle, infection occurs by contact. The incubation period of anthrax is on average 3-5 days. Diagnostics is carried out in 3 stages: microscopy of sputum or separated skin elements, back-sowing, bioassays on laboratory animals. Anthrax is treated with penicillins. In the cutaneous form, it is combined with local treatment of ulcers and carbuncles.
Anthrax is an acute, especially dangerous infectious disease that occurs in humans and animals when infected with Bacillus anthracis, occurring with the formation of specific carbuncles on the skin, or in septic form.
Bacillus anthracis is a large, encapsulated, gram-positive, facultatively anaerobic, spore-forming rod-shaped bacterium with chopped ends. It forms spores in contact with oxygen, in this form it can persist in the environment for a long time (several years in water, decades in the soil, sometimes germinating and forming new spores). It remains viable after five minutes of boiling, dies only after 12-15 minutes of exposure to liquid steam, for 5-10 minutes at a temperature of 110 ° C. Dry heat with a temperature of 140 ° C requires 3 hours to destroy bacterial spores, disinfectants (1% formalin solution, 10% caustic soda) – 2 hours.
Vegetative forms in the external environment are unstable, die during boiling and disinfection. The anthrax bacillus secretes a three-component exotoxin (antigenic, edematous and lethal factors), which is rather unstable, collapses when heated to 60 ° C. The source and reservoir of anthrax in the natural environment are herbivores, in settlements – livestock (large and small). In animals, anthrax occurs in a generalized form, contagion occurs throughout the disease (animals secrete the pathogen with feces) and within 7 days after death (without opening and butchering the carcass). The skin, wool and their processed products can remain contagious for many years.
Infection of animals occurs by eating food or water containing anthrax spores, or by insect bites that carry the pathogen from sick animals, infected corpses, objects contaminated with spores. Of particular danger are the spores remaining in the soil, forming an epidemic focus, which can be affected during construction, hydro-reclamation, geophysical and other works, as a result of which anthrax spores come to the surface and can infect animals and humans.
A sick person does not pose a significant epidemiological danger to other people, but can serve as a source of infection for animals. The mechanism of transmission of anthrax is usually contact (penetration of the pathogen occurs through damaged skin and mucous membranes). Most often, people become infected through contact with sick animals and the processing of carcasses, the manufacture of items from animal raw materials, the culinary processing of infected meat. The incidence of anthrax is divided into professional and domestic. Cases of the implementation of the food route of transmission, as well as the inhalation of bacteria are extremely rare.
The natural susceptibility of a person to anthrax is low, the development of the disease occurs in 20% of people who have had contact with the pathogen, but with the implementation of the air-dust pathway of infection, the incidence is almost one hundred percent. Anthrax is more often infected by men of active age, mainly in rural areas.
Anthrax occurs in two clinical forms: cutaneous and generalized.
- The cutaneous form, which occurs in the vast majority of cases (95% or more), is divided into carbuncular, bullous and edematous varieties, depending on the nature of skin manifestations.
- The generalized form also comes in three types: pulmonary, intestinal and septic.
The incubation period of anthrax usually takes 3-5 days, but it can be delayed up to a week or two, and also take several hours. The most common clinical form of anthrax is carbuncular. At the same time, a carbuncle is formed on the skin at the site of the introduction of the pathogen, successively passing through the stages of spots, papules, vesicles and ulcers. First, a red painless spot is formed, which quickly transforms into a copper-red (sometimes purple) papule raised above the surface of the skin. At this stage, patients are usually concerned about itching and some burning of the affected area.
After a few hours, the papule progresses into a vesicle filled with serous fluid about 2-4 mm in diameter. The contents of the vesicle soon acquire a dark, sometimes purplish-purple, shade as a result of hemorrhage. Opening (independently or when combing), the vesicle forms an ulcer with a dark brown bottom, raised edges and a detachable serous hemorrhagic character. In a typical course, the primary ulcer is girdled with new vesicles, which merge upon opening and increase the ulcerative defect.
After a few days (sometimes up to two weeks), a black necrotic scab forms in the center of the ulcer, gradually replacing its entire bottom. In appearance, the carbuncle resembles a burnt crust, painless, surrounded by a purplish-red inflammatory roller rising above the unaffected skin. The tissues around the carbuncle are pronounced edematous, often the edema captures a significant area (especially in the case of localization in places with loose subcutaneous tissue, for example, on the face). When the carbuncle is located on the face, there is a high probability of swelling spreading to the upper respiratory tract and the development of life-threatening asphyxia.
The disease is accompanied from the very beginning by significant intoxication (headache, weakness, adynamia, aching muscles, lower back, possible abdominal pain), fever. After five to six days, the body temperature drops sharply, there is a regression of general and local clinical manifestations. The scab is rejected after 2-3 weeks, the ulcer gradually heals, leaving a rough scar.
As a rule, a carbuncle is formed in a single copy, in rare cases their number can reach 10 or more, which significantly aggravates the course of the disease. The greatest danger is represented by carbuncles on the head, neck, mucous membranes of the oral cavity and nose, which noticeably worsen the course and threaten to be complicated by sepsis.
The edematous form at the first stage is limited by the swelling of the tissues, the carbuncle is formed later and is quite large in size. The bullous variety is characterized by the formation of blisters filled with hemorrhagic contents in the area of the entrance gate of infection, which transform after opening into extensive ulcers, progressing into carbuncles.
In generalized forms of anthrax, a predominant lesion of the respiratory organs (pulmonary form) is characteristic. Clinical manifestations resemble those of the influenza: symptoms of intoxication are accompanied by cough, runny nose, lacrimation, increased breathing, tachycardia, shortness of breath. This phase of the disease can last from several hours to two days, after which there is a significant increase in signs of intoxication, fever reaches critical figures (39-40 degrees), chills are pronounced. Sometimes during this period there are pains and tightness in the chest, when coughing, copious sputum with a bloody admixture is released, when clotting it resembles cherry jelly. Subsequently, there is an increase in oliguria, signs of cardiovascular insufficiency, pulmonary edema. The duration of the last phase of the disease does not exceed 12 hours, patients are conscious.
The intestinal variety of the generalized form of anthrax, which has an extremely unfavorable outcome, is the most severe. The first phase, as well as in other cases, is characterized by fever and severe intoxication, accompanied by burning and sore throat, and lasts up to a day and a half, then this symptom is joined by severe cutting abdominal pain, nausea, vomiting with blood, diarrhea. Blood is also visually detected in the feces. In the third phase, there is an increasing cardiac decompensation, the face acquires a purple or bluish-pink hue, injections of sclera are noted, petechial or hemorrhagic rashes may be on the skin. Patients are anxious, fearful.
The septic variety of the generalized form proceeds in the form of primary or secondary (which was a complication of another form of anthrax) sepsis. At the same time, there is a very rapid increase in the symptoms of intoxication, numerous hemorrhages on the skin and mucous membranes, often the meninges are affected. This form often progresses with the development of infectious and toxic shock.
Anthrax can be complicated by meningitis, meningoencephalitis, swelling and swelling of the brain, pulmonary edema, asphyxia, peritonitis, gastrointestinal bleeding and intestinal paresis. Generalized forms easily develop into sepsis and infectious-toxic shock.
The specific diagnosis of anthrax includes three stages: microscopic examination of biological materials (sputum, discharge of skin elements, pleural effusion, feces), culture isolation by sowing on nutrient media and bioassays on laboratory animals. As serological diagnostic methods, Ascoli thermal precipitation reaction, luminescent serological analysis, and some other techniques are used. Patients are given a skin-allergic test with anthraxin.
Radiography of the lungs with a generalized pulmonary form shows a picture of pneumonia or pleurisy. In such cases, a patient with anthrax needs additional consultation with a pulmonologist. If necessary, a pleural puncture is performed. At the beginning of the disease, a dermatologist’s consultation is required to differentiate the skin manifestations of anthrax. All studies with anthrax bacillus are carried out in specialized equipped laboratories due to the particular danger of this disease.
Etiotropic treatment of anthrax is carried out with penicillin, prescribing it intramuscularly for 7-8 days or more, until the symptoms of intoxication are relieved. Inside, doxycycline or levofloxacin can be prescribed. In severe cases, intravenous injections of ciprofloxacin are used. Simultaneously with antibiotic therapy, the administration of anti-ulcerative immunoglobulin is prescribed (it is administered warmed up half an hour after the injection of prednisone).
Detoxification therapy is indicated for patients with anthrax – infusion of detoxification solutions with prednisone and forcing diuresis. Severe complications are treated according to the developed methods of intensive therapy. Aseptic dressings are applied to ulcers and carbuncles. Surgical removal of carbuncles is categorically contraindicated due to the possible generalization of infection.
Prognosis and prevention
Skin forms of anthrax have a favorable prognosis, generalized forms often end in death. Modern methods of treatment contribute to a significant reduction in the adverse outcomes of this disease, so it is extremely important to seek medical help in a timely manner.
Sanitary and hygienic measures for the prevention of the incidence of anthrax include veterinary and health measures, the task of which is to identify, control and sanitize epidemiological foci, monitoring the condition of pastures, water sources, livestock farms, routine vaccinations of animals, hygienic rationing during the processing of animal raw materials, its storage and transportation, burial of fallen livestock.
Individual prevention consists in compliance with sanitary and hygienic rules when working with animals, specific vaccination for persons with high occupational risks of infection. Identified foci are subject to disinfection. Emergency prevention is carried out no later than 5 days after contact with suspicious objects, it is a course of preventive antibiotic therapy.