Epidemiology, clinical picture, treatment and prevention of leptospirosis
Leptospirosis is a naturally occurring disease that is transmitted from animals to humans and affects the liver, nervous system, and kidneys. The causative agents of leptospirosis are mobile, spiral-like bacteria of the genus Leptospira.
Natural reservoirs of infection are:
- insectivores (earthworms, hedgehogs);
- rodents (rats, mice and others);
- domestic animals (cows, dogs, sheep and others);
- fur-bearing animals (nutria, sandpipers and others).
Studies of the signs of leptospirosis in animals have shown that they can be asymptomatically infected, and can also become seriously ill. But in any case, an infected animal is the source of the spread of leptospirosis.
Ways of infection
The causative agent enters the human body with water, food, less often - by direct contact with an infected animal. You can become infected with leptospirosis:
- during agricultural works;
- when bathing, washing and swallowing water - both fresh and sea;
- when using products that have been contaminated with animal urine;
- when in contact with bacteria-carrying patients;
- when bitten by an infected animal.
A person who has contracted leptospirosis develops a stable, but not specific, immunity. This means that there is a high probability of re-infection, but with leptospires of a different subspecies with a different antigenic structure.
Symptoms of leptospirosis in a sick person, complications and prognosis of the disease
In the development of the clinical picture of leptospirosis, four periods are distinguished:
- incubation (hidden), the duration of which varies from several days to one month;
- initial, lasts no more than a week;
- a period of exacerbation of the disease with an average duration of two weeks;
- period of convalescence (recovery).
According to the clinical course, icteric and non-icteric forms of leptospirosis are distinguished. The course of the disease can be mild, moderate and severe. Most often there are non-bilious forms of mild and moderate course, as well as erased forms of infection, which are detected only during retrospective laboratory diagnosis of leptospirosis.
With classical development, the disease begins acutely with severe fever (high temperature and chills), which can last up to two weeks. The patient complains of headache, muscle pain, photophobia, lack of appetite. His face is swollen, his eyes are red, with hemorrhages, there may be herpes rashes on his lips. Blood pressure is low, the pulse is rare. Vomiting, diarrhea are possible.
By the end of the first week, a spotty rash may appear on the body. From the first days, manifestations of the hemorrhagic syndrome of leptospirosis are noted: hemorrhages on the skin, nosebleeds, red blood cells in the urine and other signs. At the height of the disease, significant hemorrhages in the muscles of the anterior abdominal wall and lower back, uterine and intestinal bleeding may develop. Cough, shortness of breath, hemoptysis, chest pains are possible.
The cardiovascular system reacts with an even greater decrease in pressure, but already with a more frequent heartbeat, arrhythmia, and sometimes with the development of cardiovascular insufficiency.
Urine becomes dark, bloody. Its quantity noticeably decreases until it is completely absent - a consequence of the developing kidney failure.
Impression of the nervous system is manifested by excitement, very severe headaches, insomnia. Meningitis or encephalitis may develop.
Jaundic forms usually run very hard. Jaundice appears already in the first week of the disease, gradually progresses, the skin and mucous membranes acquire a saffron shade. Against the background of jaundice, hemorrhagic and pulmonary manifestations, kidney and liver failure occur.
With a favorable course of leptospirosis and correctly selected treatment, recovery occurs by the end of 3-4 weeks. But restlessness, depression and irritation can persist for a long time.
Approximately a quarter of cases develop relapses of the disease with less severe symptoms.
Possible complications of leptospirosis:
- acute kidney and liver failure;
- acute respiratory distress syndrome;
- infectious-toxic shock;
- myocarditis;
- pericarditis;
- hemorrhages in the adrenal glands, lungs, muscles;
- pulmonary bleeding;
- hemorrhagic pulmonary edema;
- meningitis;
- encephalitis;
- eye injuries - uveitis, iridocyclitis and others;
- children may develop pancreatitis, cholecystitis, arterial hypertension and other pathological conditions;
- in pregnant women, transplacental transmission of infection to the fetus is possible, which leads to impaired development and even death.
Non-jaundice forms are extremely rarely fatal. Mortality in isolated cases of jaundiced leptospirosis is no more than 2%, and in epidemic outbreaks of infection - 15% or more.
Leptospirosis diagnosis methods
For suspicion of leptospirosis, the following laboratory tests are performed:
- clinical and biochemical blood analysis;
- general analysis of urine;
- spinal puncture;
- X-ray of chest organs;
- dark field microscopy of blood, urine and cerebrospinal fluid to detect leptospira in them;
- inoculation of biological material (blood, cerebrospinal fluid, urine) on nutrient media in order to identify the causative agent;
- serological blood tests for leptospirosis (RNHA, RMA, RAL, RZK) to detect an increase in the number of antibodies to leptospira in blood serum;
- determination of IgM antibodies by ELISA and detection of DNA of pathogenic leptospira using test systems developed on the basis of PCR.
You can read about these and other methods of diagnosing leptospirosis on our website Dobrobut.com.
Clinical symptoms of leptospirosis in a sick person, supported by the results of additional examination methods, make it possible to make the correct diagnosis and start the necessary treatment in a timely manner.
Treatment and prevention of the disease, vaccine against leptospirosis
An important point in the treatment and prevention of leptospirosis is mandatory hospitalization, which is explained by the high risk of developing complications and relapses of the disease, as well as the need for dynamic clinical and laboratory examination of the patient.
Treatment of leptospirosis is a complex of the following measures:
- bed rest for the entire period of fever;
- milk-vegetable diet;
- antibacterial therapy for at least 7 days;
- introduction according to a special scheme of anti-leptospirosis immunoglobulin, its combination with antibiotics reduces the risk of disease recurrence and gives an excellent clinical effect;
- detoxification therapy;
- preparations for improving blood coagulation;
- painkillers;
- vitamins;
- according to indications - hormonal drugs, diuretics and others.
Patients who have been discharged from the hospital are shown dispensary observation for six months by an infectious disease specialist with the participation of a neuropathologist, an ophthalmologist and a nephrologist.
Immunoprophylaxis of the disease is carried out only according to epidemic indications with an inactivated vaccine against leptospirosis to all citizens from the age of seven.
Mandatory vaccination is required:
- persons who work at livestock enterprises located in areas dangerous for leptospirosis;
- persons engaged in slaughtering sick livestock and processing carcasses of sick animals;
- persons who work with live cultures of leptospirosis;
- persons engaged in catching and keeping homeless animals.
General prevention of leptospirosis involves the following measures:
- protection of reservoirs against infection of water by sick animals;
- destruction of rats and mice;
- compliance with the rules of personal safety equipment by employees of dysfunctional livestock farms, slaughterhouses and meat processing plants.