LEPTOSPIROSIS

Leptospirosis is an acute infectious disease from the zoonotic group caused by leptospira, with a primary lesion of the kidneys and liver, cardiovascular and nervous systems. Diseases that were previously determined in isolation depending on the leptospira serotype are considered as clinical variants of one nosological form.

Etiology. Leptospira is an elongated corkscrew-shaped cell, not resistant to adverse environmental conditions. The causative agent is distinguished by a variety of forms. Most outbreaks are associated with leptospira icterohemorrhagic, canicola, pomona, influenza typhoid, hebdomadis, less often with other numerous forms of leptospira. The most common source of human infection is livestock, rodents, dogs and water. The main reservoir of the pathogen, especially in cities, are rats, which pollute the environment and water bodies with their secretions. Circulation of the pathogen among rats is possible when sewage or water sources are contaminated. Food products can become a factor in the transmission of an infectious principle only if they are intensively infected by rats.

Over the past decades, there have been changes in the etiological structure of leptospirosis. If in the post-war years in the Ukrainian SSR pathogens such as influenza and pomona prevailed, associated with water outbreaks caused by infection from agricultural and wild animals, then in recent years the leading factor has become icterohemorrhagic leptospirosis, which has led to a marked increase in severe clinical forms with high mortality.

Epidemiology. Leptospirosis is common on all continents. The bulk of diseases are associated with the water factor - swimming in rivers, ponds, lakes, fishing. This explains the summer seasonality, which is especially pronounced during hot days. But even in winter, there are cases of infection of people as a result of contact with rodents at livestock farms, food enterprises, grocery stores, and dwellings inhabited by rodents. Infection can occur when hunting for muskrats, caring for nutria in home breeding conditions. There remains an increased incidence among certain groups associated with caring for sick animals (veterinarians, livestock specialists, milkmaids, pigs), with slaughter at meat processing plants, and work in mines where there are rodents.

Especially convincing are the cases of people who, in the presence of skin abrasions, scratches, cuts, abrasions, the first symptoms of leptospirosis appeared a few days after bathing in a river, a pond with stagnant water. The water factor of infection, which can be considered the main one, allows us to consider leptospirosis as a disease of dirty water. Group diseases, especially anicteric forms, are often associated with field agricultural work. Hence the names of such fevers - "meadow", "water", "mowing".

Pathogenesis. Leptospira penetrates into the human body through the mucous membranes of the digestive system, conjunctiva, skin, leaving no inflammatory changes at the site of introduction. Even minor damage. scratches, abrasions can become the gates of infection. Once in the body, leptospira are carried by blood and lymph to organs rich in reticuloendothelial tissue, mainly to the liver, kidneys, and spleen. Here they multiply rapidly. Leptospiremia reaches its full development by the 3-5th day of illness. During this period, the generalization of clinical symptoms of leptospira can be detected in the blood, as well as in the cerebrospinal fluid, where they enter, having overcome the blood-brain barrier. The accumulation in the blood of the decay products of leptospira leads to sensitization of the body, the occurrence of hyperergic reactions. The most important pathogenetic factor is the defeat of blood capillaries. An increase in their permeability is clinically manifested by hemorrhagic syndrome. It comes to the fore in the picture of pathoanatomical changes in the internal organs in the form of extensive hemorrhages in the kidneys, liver, spleen, adrenal glands, digestive system. Thrombocytopenia and a decrease in blood clotting are of great importance in the origin of hemorrhages. The inflammatory process in hepatocytes is often accompanied by jaundice. Autoimmune processes are involved in the development of the disease.

Under the action of specific antibodies, leptospira disappear from the blood by the end of the 1st week of illness. Their further intensive accumulation occurs in the kidneys. Damage to the convoluted tubules leads to impaired urination, up to uremia, the main cause of death. After the illness, a strong and long-lasting active immunity is formed.

Clinic differs in considerable variety - from a short-term febrile state to extremely severe forms, ending in death. The duration of the incubation period is from 3 to 14 days. In some cases, this period may be reduced to 2 days. Sometimes, for example, with a single bath in a pond, the incubation period can be set with maximum accuracy. Only occasionally there is a gradual development in the form of malaise, weakness In most cases, the disease begins with acute chills, fever The temperature rises to 39-40 ° C, is relapsing in nature, lasts 5-8 days, and then decreases critically or by the type of accelerated lysis Subsequently, it may occur the second, less prolonged wave of fever - the disease recurs. As leptospiremia develops, intoxication increases: appetite disappears, nausea, vomiting, headache, sometimes delirium, loss of consciousness appear. Patients may remain in a state of inactivity. The slightest effort is associated with widespread myalgay. Particularly disturbing is the pain in the calf muscles, sometimes expressed to such an extent that patients can hardly move, hardly keep on their feet. Sometimes pain may be absent. Abdominal syndrome associated with damage to the abdominal muscles is possible.

The appearance of the patient is characteristic: hyperemia and puffiness of the face, pronounced injection of the vessels of the sclera, up to hemorrhages under the conjunctiva. An early roseolous-papular ephemeral rash is possible. In severe cases, it acquires a petechial character. Frequent herpetic eruptions on the lips, near the wings of the nose, enanthema of the mucous membrane of the pharynx. Hemorrhagic manifestations are characteristic - nosebleeds, vomiting in the form of coffee grounds, hematuria. Extensive bruising remains at the sites of intravenous injections. Changes in the lungs vary from mild catarrhal phenomena to hemorrhagic pneumonia. Muting and deafness of heart sounds, systolic murmur at its apex are noted. The pulse is slow, tachycardia, arrhythmia are possible. A tendency to hypotension is determined due to a decrease in mainly diastolic pressure. Possible collapses, taking a protracted nature, infectious-toxic shock, dyspnea. Electrocardiographic changes in the heart muscle, a decrease in functional contractility, the phenomena of acute toxic-infectious myocarditis, rhythm and conduction disturbances are noted. On the ECG, a change in the final part of the ventricular complex is determined: downward displacement and deformation of the S-T segments, flattening and inversion of the wave T. On the 3-5th day, rapidly growing jaundice appears. The size of the liver increases. The spleen is usually not palpable. From the first days of the disease, symptoms of damage to the central nervous system appear - a sharp headache, insomnia, lethargy or increased excitability. Often, neurological symptoms are limited to meningisch, in severe cases, serous meningitis may develop. Cerebrospinal fluid comes out in frequent drops, transparent, sometimes xanthochromic, opalescent. The disease proceeds according to the type of lymphocytic meningitis with protein-cell dissociation.

In the course of the development of the disease, the symptoms of kidney damage come to the fore. Diuresis is noticeably reduced, protein, casts appear in the urine, azotemia increases. Violation of glomerular filtration and tubular reabsorption leads to anuria. A gradual increase in diuresis indicates the attenuation of the process. 3-4 l, while high rates of residual nitrogen remain for a long time, which can be explained by increased intake of nitrogen products from tissues into the bloodstream under conditions of a cyclic infectious process. The total duration of the disease is 3-4 weeks

According to the leading sign of damage to individual organs and systems, the following clinical forms of leptospirosis can be distinguished: hepatorenal, cardiovascular, pulmonary, meningeal, abdominal

Hepatorenal - one of the most common typical forms. Jaundice with hepatargia and symptoms of acute renal failure come to the fore

Cardiovascular the form is manifested by tachycardia, arrhythmia. Hypotension often develops, due to a decrease in mainly diastolic blood pressure up to the development of collapse. sudden cardiac arrest, marked deafness of heart tones, systolic murmur in the region of the heart and expansion of its boundaries, pulse lability, rhythm disturbances characteristic of myocarditis, conduction disturbances

Pulmonary the form is characterized by catarrhal phenomena of the respiratory tract, sometimes hemorrhagic pneumonia, chest pain, tachypnea, bloody sputum, a drop in blood pressure. In this variant, which is usually extremely difficult, there is a particularly high mortality

Meningeal the form is accompanied by a sharp headache, stiff neck muscles, positive symptoms of Kernig and Brudzinsky. During spinal puncture, moderate cytosis is noted, positive reactions of Pandey and Nonne - Apelt

Leptospirosis may be masked by symptoms of an acute abdomen Abdominal the form is characterized by a sharp pain in the upper abdomen Pain syndrome resembles a picture of cholecystitis, cholecystopancreatitis The appearance in these cases of jaundice, hyperleukocytosis can lead to unreasonable laparotomy

The given clinical classification is conditional, since individual variants cannot be considered in isolation, there are no clear boundaries between them. The same clinical signs (hyperthermia, headache, jaundice, hemorrhages, renal failure) can be repeated in separate forms, but the main, leading symptom allows you to navigate in the differential diagnosis of the disease

In a laboratory study, hyperleukocytosis with a neutrophilic shift is noted, sometimes up to young and myelocytes. The number of eosinophilic granulocytes almost always decreases, plasma cells appear. ESR rises to 40-60 mm / h for a short time and even exceeds these indicators Hypochromic anemia develops Hemoglobin content decreases markedly , blood clotting slows down, which is confirmed by a coagulogram As jaundice develops, the content of bilirubin in the blood reaches a high level due to the direct and, to a lesser extent, indirect fraction. The activity of enzymes, in particular aminotransferases, is moderately increased or remains within the normal range, which more indicates the presence of an inflammatory, than a necrotic process in the liver. A diagnostically important sign is a significant increase in the level of residual nitrogen, urea, creatinine. Protein is found in the urine, erythrocytes, renal epithelial cells, and casts appear.

The severe course of leptospirosis is characterized by 3 main signs of anuria, hepatargia and hemorrhage. However, these symptoms are far from always expressed. The disease can be of moderate severity and mild form with short-term fever, moderate intoxication, slight muscle pain. In these cases, liver enlargement is not accompanied by jaundice, changes of the kidneys are reduced to rapidly passing albuminuria and cylindruria, functional tests of the liver and kidneys are slightly disturbed, diuresis remains normal Complications include myocarditis, endocarditis, acute pancreatitis, polyneuritis, iritis, iridocyclitis, uveitis, generalized muscle damage of the type of long-term polymyositis

Differential Diagnosis An epidemiological history is important in recognizing leptospirosis. Especially convincing are the cases of people who, in the presence of abrasions, scratches, cuts, the first symptoms of leptospirosis appear 7-12 days after swimming in a river, a reservoir with still water. Group diseases are often associated with professional conditions, agricultural work. In recent years, there has been a noticeable increase in the incidence of leptospirosis not only in summer, but also in autumn and winter, which requires an in-depth environmental study and the necessary preventive measures.

Sometimes, in the presence of a typical clinical picture, a positive leptospira lysis reaction, the most thorough questioning of the sick does not reveal the source of infection. In such cases, the thought arises of the possibility of food contamination by rodents.

The differential diagnostic list, which includes dozens of nosological forms - viral hepatitis, sepsis, influenza, pneumonia, meningitis, cholecystopancreatitis, hemorrhagic fever with renal syndrome, trichinosis, malaria, hepatic and renal colic, secondary infectious jaundice and other diseases and conditions, testifies to the diversity symptoms that a practitioner may encounter when recognizing leptospirosis.

Despite the typical clinical picture of this disease, its diagnosis, especially in the early stages, can present significant difficulties due to the polymorphism of the infection. Frequent "masks" of it are the severity of the onset with a steep rise in temperature, as in sepsis or influenza, rapidly increasing jaundice, abdominal syndrome, making you think about cholecystopancreatitis, appendicitis, meningeal symptoms - signs that are equally inherent in many infectious and non-infectious diseases.

The relatively rare occurrence of leptospirosis can be misinterpreted as viral hepatitis. Acute onset, hyperthermia, early onset jaundice bring leptospirosis closer to viral hepatitis A. But the subsequent dynamics of clinical and laboratory data, epidemiological history (autumn-winter seasonality of hepatitis A) make it relatively easy to distinguish between them.

Icterohemorrhagic leptospirosis is similar in features to viral hepatitis B, which also has jaundice and hemorrhagic syndrome. In contrast to the rapidly developing leptospirosis with increasing kidney failure, albuminuria, azotemia, hyperleukocytosis, elevated. ESR viral hepatitis B in most cases develops gradually, gradually, accompanied by pain in the joints, an increase in the size of the liver and spleen, mild changes in the kidneys, leukopenia, pronounced activity of serum enzymes, especially aminotransferases, and a sharply slowed down ESR. To this we must add the data of epidemiological anamnesis: conducting parenteral manipulations, blood transfusions in the premorbid period, which is completely not typical for leptospirosis.

The main differential diagnostic features are given in Table. ten.

With a sudden onset with high fever, headache, general weakness, weakness, photophobia, injection of scleral vessels, malaise, one can suspect flu or ORZ. Of great importance is the epidemiological history, the use of water from dubious sources in the field. It is necessary to take into account the seasonal nature of the disease, acute respiratory infections are relatively rare in the summer and are not limited to the defeat of individual groups. With influenza, there is no pronounced pain in the calf muscles, usually there is no rash, there is no jaundice, hemorrhagic manifestations, and obvious signs of kidney failure. Leukocytosis is not typical, ESR remains normal

It is necessary to remember about serous meningitis, not so rare in infectious diseases of various etiologies. Severe headache, dizziness, neck stiffness, positive Kernig's sign, increased CSF cytosis all these signs can be observed in leptospirosis, the final diagnosis of which is established on the basis of the anamnesis, the dynamics of clinical laboratory data and the results of a serological study

Known to suffer when leptospirosis, accompanied by abdominal syndrome, jaundice, diarrhea, was mistaken for cholecystitis, cholecystopancreatitis, salmonellosis

Table 10 Differential diagnostic criteria for leptospirosis and viral hepatitis

	Leptospiroe	Viral hepatitis
The onset of the disease	Acute often sudden, without	Acute, especially with hepatitis A,
	pronounced prodromal pe	delayed in hepatitis B
Temperature	high in the initial period,	Initial gnpertermnya at hepa
	sometimes two-wave	type A, normal with hepatitis
Hyperemia of the face sclera injection	Distinctly expressed	Missing
Myalgia, pain in ncro	Signs are typical, not obya	None, joint pain
	embodied	hepatitis B
Hemorrhagic	Often found	Occurs in severe cases of hepatitis B
	early sign	Appears after the prodromal
hepatolyenal syndrome	Moderate enlargement of the liver, the spleen is rarely palpable	period In most cases, it is clearly defined
Kidney damage Cardiac ESR	Oliguria anuria Tachycardia, collapses Rapidly increases from the first	Not typical Bradycardia, hypotension Normal or delayed
	sick days
Leukocytosis	Expressed with neutrophilic	Leukopenia neutropenia
Residual blood nitrogen Aminotransferase activity	Increased Normal or slightly sheng	Normal values ​​Significantly increased from the first days
Albuminuria, qi	Usually observed	Usually absent
Lindruria
Microagglute reaction	Positive on the rise	negative
nations with leptospira
Antigenemia	Is absent	Detected in hepatitis B

Fever as one of the manifestations of leptospirosis can be mistaken for typhoid-paratyphoid disease. Leptospirosis begins acutely, typhoid fever and paratyphoid - gradually Patients with typhus are apathetic, drowsy, pale face, characteristic roseolous rash, enlarged spleen. Patients with leptospirosis are usually excited, the face is hyperemic, puffy, injection of scleral vessels is pronounced, symptoms of kidney damage, azotemia, albuminuria predominate Serological studies (hemoculture, Vidal reaction, microagglutination reaction) help to recognize Acute onset, hyperthermia can be the reason for the differential diagnosis of leptospirosis typhus, in which patients complain of a sharp headache, insomnia; hyperemia and puffiness of the face are observed, the injection erased the tremor of the hands, a roseolous rash appears, gradually turning into a petechial one. The epidemiological history and the results of serological studies are of great importance.

For leptospirosis repeatedly taken hemorrhagic fever with renal syndrome in connection with such similarities as a sudden onset with chills and hyperthermia, widespread myalgia, kidney damage, hemorrhagic manifestations, injection of scleral vessels, hemorrhages under the conjunctiva. But with leptospirosis there is no sharp pain in the lower back, Pasternatsky's symptom is negative, the relative density of urine is normal, and with hemorrhagic nephrosonephritis it sharply decreases to 1002-1003, and sometimes even to the relative density of water.

Leptospirosis must be differentiated from sepsis, which is characterized by an acute onset, hyperthermia, hemorrhages, hepatorenal syndrome, secondary jaundice, hyperleukocytosis, and elevated ESR. All these signs are possible with leptospirosis. The final diagnosis is established taking into account environmental factors, epidemiological background, the source of a possible endogenous infection (thrombophlebitis, pneumonia, endocarditis, staphyloderma), the dynamics of clinical symptoms and the results of laboratory tests.

A number of clinical and laboratory signs bring leptospirosis closer to meningococcemia, in the fulminant form of which there is a sudden onset and rapid development of the disease, widespread myalgia, acute kidney failure, hemorrhagic syndrome, hyperleukocytosis, elevated ESR. But unlike leptospirosis, meningococcemia is characterized by an abundant stellate rash with superficial necrosis of the epithelium, meningeal manifestations, sometimes memory lapses, loss of consciousness, and there is no jaundice; microscopy of a smear and a thick drop of blood reveals meningococcus. Timely and immediate diagnosis of the correct diagnosis largely decides the outcome of the disease.

The symptoms are biphasic. Both phases include acute febrile episodes; Phase 2 sometimes includes liver, kidney, and meningeal symptoms. Diagnosis is by dark field microscopy, test culture and serological testing. Treatment with doxycycline or penicillin.

Causes of leptospirosis in humans

Leptospirosis, a zoonotic disease common to many animals, can cause asymptomatic disease or serious, even fatal disease. There is a stage of carriage, in which animals excrete leptospira in the urine for many years when urinating. A person becomes infected by direct contact with contaminated urine or tissue, or indirectly by contact with contaminated water or soil. Outbreaks often follow swimming in contaminated running water. Abraded skin and exposed mucous membranes (conjunctival, nasal, oral) are common routes of infection. Dogs and rats are other likely common sources of infection. Because distinctive clinical symptoms are lacking, it is likely that many more cases go undiagnosed and unreported.

The causative agent - leptospira, forms endo- and exotoxin. There are about 200 pathological serological types of pathogens. In Russia, L. rotopa, L. grippotyphosa, L. hebdomadis.L. canicola L. tarrasovi. The pathogen persists for a long time in the external environment, dies when salt, sugar are added, when dried, boiled, exposed to sunlight, and disinfectants. Sensitive to antibiotics, die in an acidic environment.

Pathogenesis. Leptospira enters the body through the mucosa, gastrointestinal tract, conjunctiva, and skin. The pathogen easily penetrates into the blood and vascular walls, liver, kidneys, adrenal glands, lungs, spleen, cerebrospinal fluid. There, the pathogen multiplies and accumulates. Primary and secondary bacterial intoxication develops. The walls of blood vessels and the blood coagulation system (DIC) are damaged - thrombohemorrhagic syndrome, which leads to damage to internal organs, hemorrhages appear in organs, in the brain, on the skin, pleura, and peritoneum. There may be anemia, oliguria, and in severe cases uremic coma.

Epidemiology of leptospirosis in humans

Foci - from the Arctic to the tropics.

Sources of infection:

• wild animals, small rodents;
• Pets;
• commercial - nutria, foxes, arctic foxes.

Transmission factors: water, food, products, household items.

Infection can be when bathing, through damaged skin. Animals become infected through water, feed and sexual tract. Seasonality - from June to September. There may be professional flashes.

Symptoms and signs of leptospirosis in humans

The incubation period ranges from 2 to 20 (usually 7-13) days. The disease is biphasic. The septic phase begins abruptly with headache, severe muscle pain, chills, fever, cough, chest pain, and, in some patients, hemoptysis. On the 3rd or 4th day, a pronounced injection of the vessels of the conjunctiva usually appears. Splenomegaly and hepatomegaly are uncommon. This phase lasts 4-9 days, with recurring chills and fever, which is often >39°C. Then the temperature drops. The 2nd or immune phase occurs between the 6th and 12th day of illness, correlates with the appearance of antibodies in the serum.

The fever and earlier symptoms return, and meningitis may develop. Acquired during pregnancy, leptospirosis, even during the recovery period, can cause fetal growth retardation.

Weill syndrome (icteric leptospirosis) is a severe form with jaundice and usually azotemia, anemia, impaired consciousness, and ongoing fever. The beginning is similar to less severe forms. However, then hemorrhagic manifestations develop. Thrombocytopenia may occur. Hepatocellular damage is minimal and recovery is complete. With anicteric forms of lethal outcomes are not observed.

Mortality in jaundice is 5-10%; it is higher in patients >60 years of age.

The icteric form - Vasiliev-Weil's disease - icterohemorrhagic leptospirosis occurs when the blood is infected with leptospira. In Russia, it occurs in isolated cases.

The anicteric form has a milder course, fatal outcomes are extremely rare. The onset is acute, fever, high temperature, weakness, insomnia, pain in the muscles (calf). From the 4th day, bleeding from the nose, stomach, intestines, from the gums, hemorrhages in the mucous membrane of the eye, the face is puffy, hyperemic, the sclera are injected. On the 3-4th day jaundice appears. The intensity can be different, the condition worsens, petechiae appear on the skin, mucous membranes, muffled heart tones, tachycardia, bradycardia. The pressure drops. There may be toxic shock. Tongue dry, lined. On palpation, the liver is enlarged, the abdomen is painful. Sometimes there may be vomiting, diarrhea without pathological impurities. There may be OPN less than 500 ml of urine, decreased diuresis. Persistent headaches, lethargy or agitation, sometimes delirium due to cerebral edema, meningeal symptoms. By the end of the 2nd week, the condition improves.

Complications of leptospirosis in humans

Complications: arthritis, hematuria, myocarditis, meningitis, bleeding, muscle atrophy, otitis media, mumps, psychosis, iritis, iridocyclitis.

Diagnosis of leptospirosis in humans

• Hemocultures.
• Serological testing.

Similar symptoms can be the cause of viral meningoencephalitis, hemolytic fever with renal syndrome of hantavirus nature. The presence of biphasic disease can help differentiate leptospirosis. Leptospirosis should be suspected in any patient with a fever of unknown origin who may have been exposed to a lesion of leptospirosis.

In patients with suspected leptospirosis, blood cultures, acute phase antibody titers and convalescence (3–4 weeks), blood counts, serum biochemistry, and liver function tests should be performed. Meningeal manifestations determine the need for lumbar puncture; CSF cell count between 10 and 1,000/mL (usually<500/мл), с преобладанием мононуклеаров. Глюкоза ЦСЖ в норме; белок <100 мг/дл. Уровни билирубина ЦСЖ выше, чем уровни билирубина сыворотки.

The peripheral blood leukocyte count is normal or slightly elevated in most patients, but may be as high as 50,000/mL in severely ill patients with jaundice. The presence of >70% neutrophils helps differentiate leptospirosis from viral diseases. Serum bilirubin is elevated in proportion to the increase in serum aminotransferase. In patients with jaundice, bilirubin levels are usually<20 мг/дл (<542 ммоль/л), но могут достигать 40 мг/дл при тяжелой инфекции.

Diagnosis based on:

• passport data (profession);
• complaints (fever, weakness, insomnia, headaches, bleeding;
• medical history (acute onset);
• epidemiological data (bathing in water bodies, fishing, hay mowing, hunting, contact with animals, consumption of raw milk;
• clinical data (puffy, hyperemic face, injection of eye vessels, jaundice, petechiae on the skin, dry tongue, liver enlargement, abdominal pain, positive Pasternatsky symptom, decreased diuresis. Lethargy, agitation, delirium, meningeal symptoms;
• microscopy of urine, blood - detect leptospira;
• bacteriological blood tests - the answer is approximately one month later;
• biological method - infection with blood, urine, cerebrospinal fluid with the detection of leptospira in animal tissues;
• serological study - PAJI (lysis agglutination reaction) at the onset of the disease, PMAL at a later date, RSK, RNGA;
• OAM - proteinuria, erythrocytes, leukocytes, waxy casts;
• increase in urea and creatinine in the blood.

Treatment of leptospirosis in humans

• Penicillin.
• Doxycycline.

Antibiotic treatment is most effective if started early in the infection. In severe illness, penicillin or ampicillin is recommended. For less severe cases, doxycycline, ampicillin, or amoxicillin may be given. In severe cases, pathogenetic treatment is also important, including fluid therapy and correction of electrolyte disorders. Patient isolation is not required, but urine should be disinfected and disposed of carefully.

Doxycycline 200 mg once/week while visiting areas of known geographic risk of infection prevents illness.

The prognosis is favorable spontaneous recovery is often observed.

Leptospirosis is an acute zoonotic natural focal infectious disease with predominantly water transmission of the pathogen, characterized by general intoxication, fever, damage to the kidneys, liver, central nervous system, hemorrhagic diathesis and high mortality.

Etiology of leptospirosis

Leptospira are thin, mobile microorganisms of a spiral shape with a length of several to 40 nm or more and a diameter of 0.3 to 0.5 nm. Both ends of leptospira, as a rule, are bent in the form of hooks, but hookless forms are also found. Leptospira have three main structural elements: an outer shell, an axial filament, and a cytoplasmic cylinder, which is helically twisted around the longitudinal axis. They reproduce by transverse fission.

Leptospira are gram negative. These are strict aerobes; they are grown on nutrient media containing blood serum. Optimum growth is 27–30 °C, however, even under such conditions, they grow extremely slowly. Leptospira pathogenicity factors are exotoxin-like substances, endotoxin, enzymes (fibrinolysin, coagulase, lipase, etc.), as well as invasive and adhesive ability.

Leptospira are sensitive to high temperatures: boiling kills them instantly, heating to 56-60 ° C - within 20 minutes. Leptospira are more resistant to low temperatures. Thus, at –30–70 °С and in frozen organs, they remain viable and virulent for many months. Bile, gastric juice and acidic human urine have a detrimental effect on leptospires, and in the slightly alkaline urine of herbivores they remain viable for several days. In the water of open reservoirs, with a slightly alkaline or neutral reaction, leptospira persist for 1 month, and in damp and waterlogged soil they do not lose their pathogenicity up to 9 months. On food products, leptospira persist for up to 1–2 days, and under the influence of ultraviolet radiation and when dried, they die within 2 hours. Leptospira are sensitive to penicillin preparations, chloramphenicol, tetracycline and are extremely sensitive to the action of conventional disinfectants, boiling, salting and pickling. At the same time, low temperatures do not have a detrimental effect on leptospira. This explains their ability to winter in open water bodies and moist soil, completely preserving virulence.

Epidemiology of leptospirosis

Leptospirosis is one of the most common natural focal infectious diseases. The source of the infectious agent is wild, farm and domestic animals. The role of individual animal species as a source

leptospirosis infection is far from the same due to their varying degrees of sensitivity to these microorganisms and the nature of the response to infection. Animals in which, as a result of infection, a chronic, and in some cases asymptomatic process occurs, accompanied by prolonged excretion of leptospira in the urine, have the greatest epidemiological and epizootological significance. It is these animals that ensure the preservation of leptospira as a biological species. The greatest importance in the natural foci of leptospirosis is given to representatives of the order of rodents, as well as insectivores (hedgehogs, shrews). The carriage of leptospira has been proven in almost 60 species of rodents, of which 53 belong to the family of murines and hamsters.

The biological plasticity of leptospira makes it possible to adapt them to agricultural and domestic animals (cattle, pigs, horses, dogs), as well as to synanthropic rodents (gray rats, mice),

which form anthropurgic foci of infection, representing the main danger to humans (Fig. 17-3).

From an epidemiological point of view, the incidence of cattle and small cattle, as well as pigs, is important. Animals of any age are ill, but in adults leptospirosis occurs more often in a latent form, and in young animals it is more pronounced.

symptoms.

The person does not matter as a source of infection.

The main factor in the transmission of the causative agent of leptospirosis is water contaminated with secretions (urine) of infected animals. The direct causes of human infection are the use of raw water for drinking, washing from open water, swimming in small slow-flowing ponds or fording them.

Of some importance in the transmission of infection are food products contaminated with secretions of rodents. Transmission of the infection most often occurs by contact, but the food route is also possible. The transmission factors are

wet soil, grass pastures, polluted with excretions of sick animals. Infection can occur when slaughtering livestock, butchering carcasses, as well as when eating milk and raw meat. Leptospirosis often affects people who have professional contact with sick animals: veterinarians, pest control workers and agricultural workers.

For the penetration of leptospira, the slightest violation of the integrity of the skin is sufficient.

Epidemic outbreaks of leptospirosis are usually confined to the summer-autumn period. The peak incidence is in August. There are three main types of outbreaks: aquatic, agricultural and livestock.

Leptospirosis is also encountered in the form of sporadic cases that can be recorded throughout the year.

Leptospira are hydrophilic, therefore, leptospirosis is characterized by a high prevalence in areas where there are many swampy and highly humid lowlands.

In the Russian Federation, leptospirosis is one of the most common zoonoses, the incidence is 0.9–1.5 per 100,000 population. The highest incidence is in the Northwestern, Central and, especially, the North Caucasian

regions. In recent years, a clear trend towards the urbanization of the incidence has been noted - the spread in megacities (Moscow, St. Petersburg).

The natural susceptibility of humans to leptospirosis infection is significant. Post-infection immunity is strong, but type-specific, therefore, repeated diseases caused by other pathogen serovars are possible.

Measures to prevent leptospirosis

Non-specific

Prevention is carried out jointly by the bodies of Rospotrebnadzor and the veterinary service. They identify and treat valuable animals, regularly deratize populated areas, protect water bodies from pollution with animal secretions, prohibit swimming in stagnant water bodies, disinfect water from open water sources, and fight stray dogs.

Specific

Vaccination of farm animals and dogs is carried out, routine vaccination of persons whose work is associated with the risk of infection with leptospirosis: employees of livestock farms, zoos, pet stores, dog kennels,

fur farms, enterprises for the processing of livestock raw materials, employees of laboratories working with Leptospira cultures. The vaccine for the prevention of leptospirosis is administered from the age of 7 at a dose of 0.5 ml subcutaneously once, revaccination after a year.

Pathogenesis of leptospirosis

The pathogen enters the human body due to its mobility.

The entrance gates are microdamages of the skin and mucous membranes of the oral cavity, esophagus, conjunctiva of the eyes, etc. Cases of laboratory infection through damaged skin are known. With intradermal penetration in an experiment on laboratory animals, leptospira penetrate into the blood after 5–60 minutes, apparently bypassing the lymph nodes, which do not perform a barrier function in leptospirosis. At the site of the introduction of the pathogen, there is no primary affect. Further spread of leptospira occurs by the hematogenous route, while the lymphatic vessels and regional lymph nodes also remain intact. With the blood flow, leptospira enter various organs and tissues: the liver, spleen, kidneys, lungs, central nervous system, where they multiply and accumulate. Developing first phase infections lasting from 3 to 8 days, which corresponds to the incubation period.

Second phase pathogenesis of leptospirosis - secondary bacteremia, when the amount of leptospira in the blood reaches a maximum and they still continue to multiply in the liver and spleen, adrenal glands, causing the clinical onset of the disease. With the blood flow, leptospira again spread throughout the body, even overcoming the BBB. During this period, along with the reproduction of leptospira, their destruction begins as a result of the appearance of antibodies that agglutinate by the fourth day of the disease and lyse leptospira. The accumulation in the body of metabolic products and decay of leptospira is accompanied by fever and intoxication, which increases the sensitization of the body and causes hyperergic reactions.

This phase lasts for 1 week, but can be shortened to several days. The maximum concentration of leptospira by the end of the leptospiremia phase is observed in the liver. Leptospira produce hemolysin, which, by influencing the membrane of erythrocytes, causes their hemolysis and release of free bilirubin. In addition, destructive changes develop in the liver with the formation of inflammation and tissue edema. In a severe course of the disease, the main factor in the pathological process in the liver is damage to the membranes of blood capillaries, which explains the presence of hemorrhages and serous edema.

The pathogenesis of jaundice in leptospirosis is twofold: on the one hand, the breakdown of erythrocytes due to toxic effects on the membranes of hemolysin and hemolytic antigen, as well as as a result of erythrophagy by cells of the reticuloendothelial system in the spleen, liver and other organs, on the other hand, due to developing parenchymal inflammation with impaired bile formation. and excretory function of the liver.

Third phase pathogenesis of leptospirosis - toxic. Leptospira die due to the bactericidal action of the blood and the accumulation of antibodies, disappear from the blood and accumulate in the convoluted tubules of the kidneys. The toxin accumulated as a result of the death of leptospira has a toxic effect on various organs and systems. In some patients, leptospira multiply in the convoluted tubules and are excreted from the body in the urine. In this case, kidney damage comes to the fore. The most characteristic kidney damage in leptospirosis is a degenerative process in the epithelium of the tubular apparatus, so it is more correct to consider them as diffuse distal tubular nephrosis. Patients develop signs of acute renal failure with oligoanuria and uremic coma. Severe kidney damage is one of the most common causes of death in leptospirosis.

In the phase of toxemia, damage to organs and tissues is caused not only by the action of the toxin and waste products of leptospira, but also by autoantibodies formed as a result of the decay of the affected tissues and cells of the macroorganism. This period coincides with the second week of illness, but may be somewhat delayed. The toxin has a damaging effect on the capillary endothelium, which increases their permeability with the formation of blood clots and the development of DIC.

The central nervous system is affected due to overcoming the BBB by leptospira. Some patients develop serous or purulent meningitis, less often meningoencephalitis.

In some cases, specific leptospiral myocarditis occurs.

The pathognomonic symptom of leptospirosis is the development of myositis with damage to the skeletal, especially the calf muscles. The lungs (leptospirosis pneumonia), eyes (iritis, iridocyclitis) are often affected, less often other organs.

Clinical picture of leptospirosis

The incubation period lasts from 3 to 30 (usually 7-10) days.

Classification

There is no generally accepted classification of leptospirosis.

According to the clinical course, mild, moderate and severe forms of leptospirosis are distinguished. A mild form can occur with fever, but without severe damage to the internal organs. The moderate form is characterized by severe fever and a detailed clinical picture of leptospirosis, and the severe form is characterized by the development of jaundice, the appearance of signs of thrombohemorrhagic syndrome, meningitis and acute renal failure. According to clinical manifestations, icteric, hemorrhagic, renal, meningeal and mixed forms are distinguished. Leptospirosis can be complicated and uncomplicated.

The main symptoms and dynamics of their development

The disease begins acutely, without a prodromal period, with severe chills, an increase in body temperature within 1-2 days to high numbers (39-40 ° C).

The temperature remains high for 6–10 days, then it decreases either critically or by shortened lysis. In patients not treated with antibiotics, a second febrile wave can be observed. There are other symptoms of intoxication, such as severe headache, back pain, weakness, lack of appetite, thirst, nausea, and sometimes vomiting. Conjunctivitis may also develop during this period.

A characteristic sign of leptospirosis is pain in the muscles, mainly calf muscles, but pain in the muscles of the thigh and lumbar region may occur. In severe forms, the pain is so strong that it makes it difficult for the patient to move. On palpation, a sharp soreness of the muscles is noted. The intensity of myalgia often corresponds to the severity of the course of the disease. Myolysis leads to the development of myoglobinemia, which is one of the causes of acute renal failure. In some patients, myalgia is accompanied by skin hyperesthesia. Attention is drawn to hyperemia of the skin of the face and neck, injection of blood vessels of the sclera. On examination, a “hood symptom” is revealed - puffiness of the face and flushing of the skin of the face, neck and upper half of the chest, injection of scleral vessels.__

With a severe course of leptospirosis, icterus of the sclera and yellowness of the skin occur from the 4–5th day of the disease. The clinical course can be schematically divided into three periods:

• elementary;
• height;
• convalescence.

In 30% of patients in the initial, and sometimes in the period of the peak of the disease, exanthema occurs. The rash consists of polymorphic elements located on the skin of the trunk and extremities. The rash can be morbilliform, rubella-like, less often scarlatiniform. Urticarial elements may also occur.

Macular rash tends to merge individual elements. In these cases, erythematous fields are formed. Erythematous exanthema is most common, the rash disappears after 1-2 days. After the disappearance of the rash, pityriasis peeling of the skin is possible. Often there are herpetic eruptions (on the lips, wings of the nose). Thrombohemorrhagic syndrome is manifested, in addition to a petechial rash, by hemorrhages into the skin at injection sites, nosebleeds,

hemorrhages in the sclera.

During this period, there may be a slight sore throat, coughing. An objective examination often reveals moderate hyperemia of the arches, tonsils, soft palate, on which you can see the enanthema, hemorrhages.

In some patients, the submandibular, posterior cervical lymph nodes increase.

From the side of the cardiovascular system, relative bradycardia and a decrease in blood pressure attract attention. Heart sounds are muffled, with ECG signs of diffuse myocardial damage can be detected. Perhaps the development of specific leptospirosis pneumonia or bronchitis. When it occurs, dullness of the lung sound and pain in the chest are observed. The liver is enlarged, moderately painful on palpation, in almost half of the patients the spleen is palpated.

Signs of CNS damage in leptospirosis are meningeal syndrome: dizziness, delirium, insomnia, headache and positive meningeal symptoms (neck stiffness; Kernig's symptom; upper, middle and lower Brudzinsky symptoms). In the study of cerebrospinal fluid, signs of serous meningitis are noted: cytosis with a predominance of neutrophils.

On the part of the urinary system, signs of acute renal failure can be observed: a decrease in diuresis up to the development of oligoanuria, the appearance of protein in the urine, hyaline and granular cylinders, and renal epithelium. The content of potassium, urea, creatinine is increased in the blood. In the study of peripheral blood, an increase in ESR and neutrophilic leukocytosis with a shift of the formula to the left, often to myelocytes, aneosinophilia are determined.

At the height of the disease, from the 5-6th day, in severe cases, intoxication increases, headache, muscle weakness increase, aversion to food appears, vomiting becomes more frequent, although the body temperature decreases. In some patients, jaundice occurs, the intensity of which corresponds to the severity of the course of the disease and which lasts from several days to several weeks. During this period, the most severe manifestations of hemorrhagic syndrome are observed: hemorrhages in the skin and mucous membranes, bleeding from the gums, gastrointestinal bleeding, hemoptysis, hemorrhages in the membranes and brain substance. More often, hemorrhagic syndrome is observed in the icteric form of the disease. There are clinical and ECG signs of damage to the heart, meninges. Kidney damage deserves special attention: increasing azotemia, proteinuria.

As a result of hemolysis and impaired erythropoiesis, anemia of the hyporegenerative type, thrombocytopenia, leukocytosis, lymphopenia increase, platelet aggregation is impaired, ESR reaches 40–60 mm/h. A biochemical blood test reveals moderate hyperbilirubinemia with an increased content of both bound and free bilirubin with a slight increase in transferase activity. At the same time, due to muscle damage, the activity of creatine phosphokinase sharply increases, the protein-synthetic function of the liver is disturbed, and the level of albumin decreases.

The condition begins to improve from the end of the second week, the period of convalescence from the 20-25th day of illness. During this period, a relapse of the disease is possible, which usually proceeds easier than the main wave. Otherwise, body temperature

steadfastly normalizes, but asthenic syndrome persists for a long time, a polyuric crisis is possible. The functions of the liver and especially the kidneys are restored slowly, the insufficiency of the function of the tubules persists for a long time, which is manifested by isohyposthenuria and proteinuria; trophic disturbances, anemia increase are possible.

In different regions, the course may have differences in the frequency of icteric forms, CNS damage, and the development of acute renal failure. The most severe leptospirosis is caused by L. interrogans icterohaemorragiae. Abortive and erased forms of the disease are ubiquitous, occurring with a short-term (2–3 days) fever without typical organ pathology.

Complications of leptospirosis

ITSH, acute renal failure, acute hepatic renal failure, ARF (RDS), massive bleeding, hemorrhage, myocarditis, pneumonia, in the later stages - uveitis, iritis, iridocyclitis.

Mortality and causes of death

Mortality varies from 1 to 3%. Causes of death - the above complications, most often acute renal failure.

Diagnosis of leptospirosis

Clinical

Epidemiological anamnesis plays an important role in the diagnosis of leptospirosis. The profession of the patient (agricultural worker, hunter, veterinarian, pest control), as well as contact with wild and domestic animals, should be taken into account. Attention should be paid to whether the patient bathed in open water, since the contamination of water with leptospira in some regions is extremely high.

The diagnosis of leptospirosis is established on the basis of characteristic clinical symptoms: acute onset, hyperthermia, myalgia, facial flushing, combined damage to the liver and kidneys, hemorrhagic syndrome, acute inflammatory changes in the blood.

Specific and non-specific laboratory diagnostics

Laboratory confirmation of the diagnosis is obtained by bacterioscopic, bacteriological, biological and serological studies. In the first days of the disease, leptospira is detected in the blood using dark-field microscopy, later in the urine sediment or CSF.

When sowing blood, urine or CSF on nutrient media containing blood serum, it is possible to obtain more reliable results, although this method takes time, since, as already mentioned, leptospira grow rather slowly.

Primary cultures of blood, urine, tissues of organs suspected of containing leptospira are recommended to be kept for the first 5–6 days at a temperature of 37 ° C, and then at 28–30 ° C. __ The biological method consists in infecting animals: mice, hamsters and guinea pigs , but recently this method has had many opponents who consider it inhumane.

The most informative are serological methods, in particular the microagglutination reaction recommended by WHO. An increase in antibody titer of 1:100 or more is considered positive. Also use RAL leptospira in the Dutch modification. Antibodies appear late, not earlier than the 8–10th day of illness, so it is advisable to study paired sera taken with an interval of 7–10 days.

Treatment of leptospirosis

Mode. Diet

Treatment is carried out in a hospital. Hospitalization is carried out according to epidemiological indications. Bed regimen in the acute period. The diet is determined by the clinical features of the disease. With the dominance of the renal syndrome - table number 7, hepatic - table number 5, with combined lesions - table number 5 with salt restriction or table number 7 with fat restriction.

Medical therapy

The main method of treatment is antibiotic therapy, which is often carried out with penicillin preparations at a dose of 4–6 million units / day or ampicillin at a dose of 4 g / day. In case of intolerance to penicillin, doxycycline is prescribed at a dose of 0.1 g twice a day, chloramphenicol at a dose of 50 mg / kg per day. With damage to the central nervous system, the dose of penicillin is increased to 12-18 million units / day, the dose of ampicillin - up to 12 g / day, chloramphenicol - up to 80-100 mg / kg per day.

The duration of antibiotic therapy is 5–10 days.

With acute renal failure in the initial stage, with a decrease in the daily amount of urine, osmotic diuretics are administered intravenously (300 ml of 15% mannitol solution, 500 ml of 20% glucose solution), 200 ml of 4% sodium bicarbonate solution per day in two divided doses. In the anuric stage, large doses of saluretics (up to 800-1000 mg / day of furosemide), anabolic steroids (methandienone 0.005 g 2-3 times a day), 0.1 g / day of testosterone are administered.

With TSS, the patient is administered intravenously prednisolone at a dose of up to 10 mg / kg per day, dopamine according to an individual scheme, then sequentially intravenously 2–2.5 liters of a solution of the Trisol♠ or Quintasol♠ type, 1–1.5 liters of a polarizing mixture (5% solution glucose, 12–15 g potassium chloride, 10–12 units of insulin). Salt solutions are first injected in a jet, then switching to drip administration (with the appearance of a pulse and blood pressure). With the development of DIC, fresh frozen plasma, pentoxifylline, sodium heparin, and protease inhibitors are used.

Indications for hemodialysis

• Two-, three-day anuria.
• azotemia
  Use hyperbaric oxygen therapy. With severe hemorrhagic syndrome, 40-60 mg / day of prednisolone is prescribed orally or intravenously 180-240 mg / day. Symptomatic treatment, a complex of vitamins are also prescribed.

Leptospirosis in humans is an acute zoonotic infection. The causative agents are spiral-shaped microorganisms called leptospira. A disease that provokes disruption of the central nervous system, kidneys, skeletal muscles, the development of jaundice, intoxication, fever and severe myalgia, is also called infectious jaundice, Japanese or water fever.

Features of the development of the disease are due to the specific factors of pathogenesis characteristic of leptospira:

• The release of endotoxin, which leads to a general intoxication of the body and a violation of the integrity of the vascular endothelium with sweating of blood from them;
• The presence of flagella, which give the pathogen maximum mobility, the ability to circular, translational, sliding movements;
• Obtaining energy only as a result of oxidative processes in fatty acids;
• The presence of pathogenic enzymes destructive for parenchymal organs in the form of hemolysin, plasmacoagulase, fibrinolysin and lipase.

The causative agent of leptospirosis enters the body through the slightest damage to the skin, mucous membranes. Also, the site of penetration may be the conjunctiva of the eye. For the development of the disease, it is enough to contact for a short period of time with water in which leptospirosis lives, or with infected animals (rodents, pigs, dogs, hedgehogs and cattle are especially susceptible to leptospirosis).

To move around the body, leptospira use the lymphatic system, without provoking inflammation of the lymph nodes. Within a short period of time, the pathogen penetrates into various tissues and internal organs, most often the lesion affects the lungs, liver, central nervous system and spleen. Here, leptospira actively multiply and accumulate (the duration of the incubation period is 14 days), after which destructive processes begin in the above organs, accompanied by intoxication, impaired blood clotting function and destruction of red blood cells.

Leptospirosis in humans is quite common due to significant susceptibility to this infection. The risk group includes the elderly, newborns and people suffering from immunodeficiency. At the same time, there is no specific resistance to pathogenic pathogens.

Ways of infection

1. Contact - if a person was in direct contact with a sick animal or touched contaminated household items, water.
2. Alimentary - when eating products from infected animals and infected plant food waste products.
3. Aerogenous - if contaminated air enters the respiratory tract.
4. Transmissible - as a result of flea bites or infected ticks.

Symptoms

The first phase of the disease, called the incubation period, lasts about two weeks, followed by a phase of clinical manifestations. It lasts no more than a month and is divided into three successive periods.

Generalization

An acute course and the following symptoms are characteristic: general intoxication, chills and high fever. The fever lasts for 5 days, aggravated by myalgia. Particularly severe pain is observed in the calf muscles, in which focal necrobiotic and necrotic changes occur. In general, the period lasts about a week.

Razgar

The duration of this period is about 14 days, during which secondary bacteremia develops and secondary damage to internal organs is observed.

Toxinemia

It is characterized by severe intoxication as a result of the release of endotoxin by gradually dying leptospira. The poisoning of the body results in infectious-toxic shock, multiple organ failure, violation of the vascular endothelium, the appearance of bruises on the internal organs, mucous membranes and skin (hemorrhages develop).

Also, the symptoms of leptospirosis include the development of jaundice due to destructive changes and hemolysis, with an aggravation of the process in the form of liver and kidney failure. The result of such disorders in the absence of timely treatment are coma.

An objective examination reveals the following signs of the disease, called the "hood symptom":

• Swelling of the face, redness of the skin;
• Change in skin color of the upper chest and neck (appearance of red pigment);
• Jaundice of the vessels of the sclera and severe injection, while there are no signs of conjunctivitis.

With the penetration of leptospira through the blood-brain barrier, purulent meningitis or meningoencephalitis develops with obvious signs in the form of stiff neck and positive symptoms of Brudzinski and Kering (the inability to fully straighten the knee joint due to reflex spasm of the calf muscles, etc.).

Feature of hemorrhages (rashes) in leptospirosis

Hemorrhages and rash can be present both on the mucous membranes and skin, and in the internal organs. The characteristic differences of such manifestations are:

• Similar in appearance to rubella, measles and scarlet fever;
• Rash affected abdomen, arms and chest;
• Disappearance of the rash after a couple of hours (in some cases) followed by pigmentation and peeling of the skin;
• Development as a result of decompensation of nasal hemorrhages, abdominal bleeding and hemorrhages (at injection sites).

It should be noted that itching can be a sign of liver failure, so you should pay attention to the obligatory accompanying symptom in the form of yellowness of the skin.

Forms of the disease

Leptospirosis in humans can occur in mild, moderate and severe forms.

Light form

Characteristic signs are fever with an increase in temperature up to 38-39 degrees with moderate general intoxication of the body and the absence of pronounced disturbances in the functioning of internal organs.

Moderate form

The fever acquires a pronounced character, the picture of the disease becomes more developed, but the manifestations of jaundice are still absent.

Severe form

Depending on the severity criteria, this form of leptospirosis is divided into types such as hemorrhagic, icteric, renal, meningeal, mixed.

The severe form of the disease is called Weil's disease, the symptoms of which appear three days after the disappearance of signs of a mild form. Leptospirosis in humans at this stage is determined by such a specific sign as Weil's syndrome, which is characterized by impaired consciousness in conjunction with jaundice, anemia and prolonged fever. This syndrome becomes most pronounced in the peak phase.

With liver damage in the region of the organ, characteristic pains occur, an increase in the size of the liver is observed, and characteristic changes occur in the blood serum. Kidney dysfunction is accompanied by signs such as hematuria, azotemia, proteinuria and pyuria.

Other specific signs of a severe form of leptospirosis include gastric and nasal bleeding, hemoptysis, and the development of aseptic meningitis. Also, there is a possibility of hemorrhagic pneumonia and hemorrhages in the adrenal glands.

Possible Complications

In some cases, acute renal failure can develop in a latent form without hemorrhagic syndrome and jaundice, ending in death after 3-5 days.

In addition, in the acute phase, cerebral edema, pneumonia and myocarditis, paralysis or paresis, as well as dangerous eye complications - iridocyclitis, iritis, uveitis, which occur a month after the pathogen enters the body, can be observed.

Diagnostic measures

When diagnosing leptospirosis in humans, the closest attention is paid to the presence of fever and its degree, the patient's appearance, thrombohemorrhagic syndrome, the severity of jaundice and the degree of kidney damage. In this case, a thorough differential diagnosis of leptospirosis is carried out, taking into account the following signs:

1. A fever that persists for about 5 days, which is also possible with other infectious diseases, including adenovirus, infectious mononucleosis, typhoid-like form of salmonellosis.
2. Jaundice, to exclude malaria, toxic or viral hepatitis.
3. Thrombohemorrhagic syndrome, which also develops with sepsis, rickettsiosis and hemorrhagic fever.

Diagnosis of leptospirosis involves the collection of not only clinical information, but also epidemiological indications, which include the presence of contacts with domestic and wild animals, occupation, the fact of swimming in open water. In addition, the examination data are taken into account, during which the degree of its enlargement is determined by palpation of the liver, diagnosing hepatomegaly by the following signs: protrusion of the organ a couple of centimeters from under the edge of the costal arch, diffuse aching or girdle radiating pain in the right hypochondrium.

Specific diagnosis by laboratory methods

As part of such activities, an analysis is performed for leptospirosis through bacterioscopic, bacteriological, serological and genetic testing. From the moment the first symptoms of leptospira appear in the blood, dark-field microscopy reveals; at a later date, urine and cerebrospinal fluid tests are taken (relevant in the presence of positive meningeal signs). After taking the analysis, the result is expected within 8 days (such a period is necessary for the growth of leptospira).

Serological analysis for leptospirosis is based on the use of a microagglutination reaction, which involves the determination of related antibodies and antigens that form agglomerates. If the increase in antibody titer exceeds 1:100, a positive reaction is declared. It is advisable to conduct such a study after the end of the 7th day from the moment the signs of the disease appear. As for the genetic study, it is used to detect the DNA of the pathogen in the biological material of the patient. For this, the polymerase chain reaction is used.

Nonspecific diagnosis of leptospirosis

Such laboratory studies involve taking tests to determine the level of ESR, residual nitrogen, bilirubin of direct and indirect fractions, protein, urobilinogen, ketone bodies, neutrophilic leukocytosis, OAM.

Medical therapy

Treatment of leptospirosis consists of etiotropic, pathogenetic and symptomatic therapy (prescription of antibiotics, prevention of complications and relief of the condition, respectively). Antibiotic therapy can be carried out with the appointment of penicillin (in the absence of an allergic reaction), drugs of the tetracycline group, gamma globulin contained in hyperimmune bovine serum.

Mild leptospirosis in humans can be treated on an outpatient basis without the need for hospitalization. As a rule, a 5-6-day course of antibiotics (tetracycline or penicillin) is carried out. With the development of adverse reactions in the form of vomiting, nausea or diarrhea, erythromycin can be used. If the patient complains of muscle and headaches, fever, ibuprofen or paracetamol can be additionally prescribed. In order to avoid recurrence of the disease, the course of treatment should not be interrupted.

Treatment of a severe form is necessarily carried out in a hospital under the supervision of doctors. Antibiotics are administered intravenously, adding droppers with patient-supporting nutrients. The need for pathogenetic therapy arises with the development of renal failure, cerebral edema, acute cardiovascular failure or DIC. To alleviate the patient's condition, hemodialysis and infusion therapy are carried out with the introduction of appropriate drugs (diuretics in case of impaired renal function, ascorbic acid and cardiac glycosides in case of heart failure, brain metabolites in case of cerebral edema, detoxification drugs and protease inhibitors in case of DIC).

The duration of treatment depends on the state of the body, the degree of damage to internal organs and the response to therapy.

rehabilitation period

After successful treatment of leptospirosis, patients should be registered with the dispensary for a period of about six months. During this period, rehabilitation measures are carried out, consisting of consultations with an ophthalmologist, neurologist, therapist or pediatrician (if the patient is a child). Six months later, the patient should appear every month for an appointment with a therapist who, if necessary, will schedule an examination with a specialist. During the first two months of rehabilitation, clinical and laboratory examinations are regularly carried out.

If at the end of the rehabilitation period the analysis for leptospirosis does not give positive results, the patient is removed from the register. Otherwise, observation with appropriate rehabilitation measures lasts for 2 years.

Preventive measures

Effective prevention of leptospirosis is possible only if the following conditions are met:

1. Timely vaccination, testing and treatment of pets. Vaccination against leptospirosis helps protect not only pets, but also family members from such an insidious disease.
2. The exclusion of visiting fresh water in the presence of abrasions or cuts on the skin.
3. Hygienic shower after swimming in rivers and lakes.
4. High-quality hygiene of working meta on farms, use of gloves and protective masks when in contact with animals.
5. Regular hand washing, especially after playing with pets and returning from the street, eating only washed fruits, vegetables and greens.

Important nuances

Unlike animals, a person infected with leptospirosis does not pose a danger to others, since he is a biological dead end in the chain of spread of the disease.

Treated leptospirosis in humans is not a guarantee of lifelong immunity due to the type-specificity of the disease. If the body is affected by another Leptospira serovar, infection can occur again.

As you can see, leptospirosis is easier to prevent than to treat. The main thing is to be attentive to your own body and contact specialists at the first suspicion. Only professional diagnostics, timely treatment and a responsible approach become the key to a successful recovery without the development of life-threatening complications.

Leptospirosis is an infectious disease caused by leptospira, microorganisms that live everywhere in conditions of high heat and excessive humidity. Leptospirosis is most common in people living in tropical countries. The carriers of the infection are animals: dogs, shrews, pigs, rats, etc. A person with leptospirosis does not pose a danger to other people.

Leptospirosis in humans: infection

The infection enters the body of animals through food or water. Infection of humans occurs through the skin through contact with contaminated animal secretions in water or wet soil. In addition, the infection can be brought by cutting infected meat or eating infected foods. Most often, veterinarians and farm workers are exposed to leptospirosis. The disease is seasonal, with cases of infection occurring in August. For a person to become ill with leptospirosis, even a fleeting contact with contaminated water is enough. If there is even the slightest damage on the skin, leptospira easily penetrate the body. They can also get inside through the mucous membranes or conjunctiva of the eyes. Once in the body, microbes begin to move through the lymphatic system. But they do not cause inflammatory processes in the lymph nodes, but through them they easily penetrate into organs and tissues, where they begin to multiply and accumulate. The incubation period lasts up to 2 weeks. Then leptospira affects the kidneys, liver, central nervous system, spleen, and lungs. They release their toxins into the blood, causing severe intoxication, destroying red blood cells and disrupting the function of blood clotting.

Leptospirosis in humans: symptoms

First, a person's temperature rises sharply, signs of intoxication appear, such as headache, chills, nausea, sleep disturbance, and constant thirst. Harbingers of leptospirosis have not yet been observed, although leptospira can already be detected in the blood and cerebrospinal fluid. Similar symptoms persist for 4 to 9 days. This is how the first phase of the disease manifests itself - leptospiremia. Then muscle pain begins to appear. Palpation of the muscles of the thighs, calves and lower back causes pain. There may be hyperemia of the neck, face, chest. Some people develop a rash, diarrhea, cough, and impaired sensitivity. In severe cases, as a result of toxemia of the internal organs, there is a risk of developing meningitis, renal failure, jaundice,

Leptospirosis in humans: diagnosis

To establish the diagnosis, they carry out As already mentioned, it is possible to identify leptospira in the cerebrospinal fluid or blood. If the disease has passed into the phase of toxemia of the internal organs, microorganisms are found in the urine. Sometimes doctors cannot immediately recognize leptospirosis and begin to suspect hepatitis, meningitis, nephritis and other pathologies in a patient.

Leptospirosis in humans: treatment

Often the condition of patients requires implementation. The disease is very serious, in 10% of cases it ends in the death of the patient. The prognosis of recovery depends on the state of the body and on the degree of pathogenicity of leptospira. Treatment is carried out by taking antimicrobial agents, such as Levomycetin, Streptomycin, Penicillin, Erythromycin. To obtain a therapeutic effect, medicines should be taken after no more than four days have passed since the moment of infection.

Prevention of leptospirosis

The main preventive methods are veterinary and sanitary measures, consisting in the identification and treatment of sick animals. It is possible to limit the spread of leptospira by leptospirosis vaccination of humans and animals. It is unacceptable to use water from dirty sources.