Leptospirosis - Causes, symptoms and treatment. MF.

Leptospirosis( Vasiliev-Weil disease, water fever, nancucci, Japanese diurnal fever) is an acute zoonotic natural-focal bacterial disease with multiple transmission mechanisms, characterized by endothelial damage to blood vessels, liver, kidneys and the central nervous system due to intoxication syndrome.

Long before the discovery of the causative agent of leptospirosis, the German scientist Weil described the symptoms of four cases of icteric diseases, and only a quarter of a century later the causative agent was discovered - by Japanese scientists it was isolated from the liver of a deceased person.

The causative agent of leptospirosis

Leptospira icterohaemorrhagiae - bacteria in the form of a tightly twisted spring, giving the appearance of strings of pearls with microscopy and pale pink color by the method of Romanovsky-Giemsa. A total of about 200 serovars( varieties of leptospira).The causative agent has pathogenesis factors that determine the course of the disease:

• the presence of flagella, due to which leptospira are more mobile and perform rotational, sliding, pendulum and incoming movements;

• receive energy by oxidizing fatty acids - this is the only source;
• the presence of endotoxin explains the damage to the vascular endothelium( with the subsequent sweating of blood from the vessels) and general intoxication;
• Pathogenic enzymes: hemolysin, fibrinolysin, plasmacoagulase, lipase - they cause destructive changes in the parenchymal organs;

Leptospira are stable in the environment and remain in open water for up to 30 days or more, in moist soil - up to 270 days, on food products - up to several days( especially at low temperatures).They are killed during drying, the action of direct UV, boiling, treatment with disinfectants. The causative agent to the following antibiotics is sensitive: tetracycline, penicillin, streptomycin, rifampicin.

Susceptibility among people is significant, mainly elderly people, newborns, people with IDS( immunodeficiency status) - are sick, ie, those who have some immunity disorders. A person does not have species resistance to pathogenic leptospira, but sensitivity to different species is not the same. As for the prevalence, it is not universal, leptospirosis is a natural focal infection that occurs in the North Caucasus, the Crimea, the Central regions of the European part of Russia, Siberia and the Far East. Foci are usually located in the forest zone, in river floodplains and wetlands - because the causative agent is hydrophilic( it develops well at high humidity).Leptospirosis is characterized by summer-autumn seasonality and peak incidence falls on August.

Causes of infection with leptospirosis

Source - sick and ill animals. Carriers - ticks, fleas. Carriers are rodents. Ways of infection:

• alimentary - through meat and other products from infected animals, through plant foods infected with products of waste sick animals;
• contact( in direct contact with a sick animal) and contact-household( when in contact with contaminated household items);
• aerogenic - by inhalation of contaminated air;
• transmissible - when bitten by infected mites or fleas.

Symptoms of leptospirosis

The incubation period or the first phase( the time interval from the moment of introduction of the pathogen to the first clinical manifestations) lasts from 7-20 days, but on average - 10. At this time, leptospires, getting on the mucosa( any area) or on the skincontaining microdamages, begin to multiply and spread through the blood( hematogenous pathway) reaching various organs, but most often affecting the liver / kidney / CNS / endothelium of the vessels. Once the concentration of the pathogen reaches a certain level, the next period appears - clinical manifestations.

The period of clinical manifestations lasts up to 4 weeks, and during this period - generalization, heat and residual effects. The disease begins sharply, with general toxicity manifestations - chills and a rise in temperature to high digits( duration of 4-5 days), myalgia( especially in gastrocnemius muscles due to focal necrotic and necrobiotic changes) and lasts about 7-10 days. After this comes the second phase - the swelling, lasting about 2 weeks, which occurs as a result of secondary bacteremia, and then secondary damage to internal organs and is characterized by toxemia( the third phase) due to the gradual death of leptospira and the release of endotoxin with their death, followed by the development of ITS(infectious toxic shock) and multi-organ failure, also systemic damage to the vascular endothelium occurs, hemorrhages( bruises) on the skin, mucous membranes and internal organs occur.

Also develops jaundice - both because of hemolysis, and because of destructive changes, resulting in liver failure. Due to vascular lesions from the kidneys, kidney failure develops. After damage to the liver and kidneys, comatose conditions quickly develop, because they cease to perform one of their carrier functions - detoxification( excretion of toxic metabolic products).At objective research - «a hood symptom» which is presented by reddening and puffiness of the face, reddening of a skin of a neck and the top departments of a thorax. Note the injectivity and ictericity( icterus) of the vessels of the sclera, without signs of conjunctivitis.

As the leptospira spreads throughout the body, it spreads across the blood-brain barrier, reaching the central nervous system, serous or purulent meningitis, or meningoencephalitis-the meningic symptoms( stiff neck muscles, Kering and Brudzinsky symptoms) are positive.

The above symptoms( hemorrhages,renal and hepatic insufficiency, ITH) are only collective images that hide the following:

• Hemorrhages - hemorrhages on the skin, mucous membranes and, in severe casess case in the internal organs. The rash has some features:

- on the skin these rashes resemble a kind of measles / rubella / scaralatin-like rash;
- localization on the chest, abdomen and arms;
- with decompensation, there are nasal, internal( internal) bleedings, at the injection site - hemorrhages
- the rash may disappear after several hours, leaving after itself peeling and / or pigmentation of

Hemorrhagia in leptospirosis

• Renal failure - characterized first by a decrease( oliguria), and then the absence of urination( anuria), as well as positive hepatic symptoms, develops uremia and a violation of the concentration of electrolytes in the blood, which contributes to toxicity.

• Liver failure - will manifest jaundice and itchy skin, icteric sclera, it may be painful in the right ileal region. But icterus also arises from the direct action of hemolysin( an enzyme of pathogenicity) - it destroys erythrocytes, releasing bilirubin.

• ITH develops as a result of direct action of exotoxin Leptospira, and under the action of endotoxin released during their death. Violation of the detoxification functions of the liver and kidneys leads to a violation of the elimination of toxic metabolic products. Also, the contribution to ITH is made by products of decay of necrotic tissues, formed as a result of destructive changes.

Diagnosis of leptospirosis

When diagnosed, weighty are the signs: fever, thrombohemorrhagic syndrome, appearance, myalgia, jaundice, kidney damage. It is very important to conduct a thorough differential diagnosis according to the leading signs:

- for a fever lasting about 5 days( typhoid / paratyphoid, infectious mononucleosis, adenovirus, typhoid-like form of salmonella, etc. - the list is very extensive, includes about 19 diseases)
-for jaundice( viral and toxic hepatitis, those with fever, sepsis and malaria)
- for thrombohemorrhagic syndrome( hemorrhagic fever, sepsis, rickettsiosis)

Diagnosis is based not only on the clinical databut also on the epidemics - the place of work( agricultural worker, hunter, veterinarian, deratigator), as well as contact with wild and domestic animals, pay attention to swimming in open water( due to the high risk of contamination of water).

When palpating the liver, hepatomegaly( or hepatosplenomegaly) is detected - the liver is enlarged and protrudes from the edge of the edge arch by 2-3 cm, palpation is painful, and the patient also points to subjective sensations in the form of blunt aching pains in the right upper quadrantpossible shingles and with irradiation).

Specific and nonspecific laboratory diagnostics

Specific diagnostics - use of bacteriological, bacterioscopic, biological and serological testing. From the first days of the disease( after the onset of symptoms), with the help of dark field microscopy, it is possible to detect leptospira in the blood, and later in urine and CSF( cerebrospinal fluid - it is taken only with positive meningic signs).But the disadvantage of this method is that it gives results after 8 days - this is the time that leptospires grow, although this is one of the most reliable methods.

The biological method is carried out by infecting laboratory animals - it is already obsolete and has lost its significance.

The serological method implies the use of PMA( a microagglutination reaction) - recommended by WHO, it consists in the determination of antigens and antibodies having an affinity between themselves and thus forming agglomerates. A positive increase in antibody titer is considered positive: 1: 100 or more, but antibodies appear no earlier than 8 days from the onset of the disease.

Genetic method - the use of PCR( polymerase chain reaction) is aimed at detecting the DNA of leptospira in biological materials from the patient.

Nonspecific laboratory diagnostics: OAB( neutrophilic leukocytosis, ↑ ESR, ↑ bilirubin of both fractions, residual nitrogen, ↑ AlT and AsT, ↑ PH), OAM( decrease in quantity, ↑ / ↓ protein, ↑ bilirubin, ↑ urobilinogen, ↑ ketone bodies ande.g.).

Treatment of leptospirosis

Treatment is performed only when strictly confined to bed and in a hospital, including etiotropic, pathogenetic and symptomatic therapy. Etiotropic therapy - the appointment of sensitive antibiotics:

• penicillin 150-200 tED / kg / day - if there is an allergy to this group of antibiotics, then you can replace it with a suitable drug from the macrolide group, because their chemical forms are similar;
• any drug from the group of aminopenicillins, tetracyclines or cephalosporins at age dosages for about two weeks, complete the intake of antibiotics 3 days later from the normalization of temperature.
• Gamma globulin from hyperimmune cowhide serum. Pathogenetic treatment is aimed at preventing or eliminating the following conditions by means of infusion therapy, hemodialysis: acute renal failure( additional fluid volume and forced diuresis by diuretic administration), acute cardiovascular insufficiency( cardiac glycosides, ascorbic acid, B1 and B6 vitamins and t.d), edema of the brain( neurovegetative blockade, the creation of adequate diuresis, brain metabolites - peratsetam, actovegin, etc.), the development of DIC syndrome( GCS, ingiprotease inhibitors, detoxification therapy, etc. - treatment of this condition is extensive and is carried out in the conditions of resuscitation ).

Rehabilitation

Illnesses are subject to medical examination for 6 months - a survey by an oculist, neurologist and pediatrician / therapist is necessary, and over the next months - a monthly visit to the pediatrician / therapist with the involvement of specialists in the clinical manifestation profile. The first two months - the implementation of clinical and laboratory examinations and, with negative results, the subject can be taken off the books. But with persistent positive results, observation is conducted for 2 years.

Complications of leptospirosis

Development of ITH, DIC syndrome, hemorrhage and intubandal bleeding, meningitis, encephalitis, polyneuritis, the occurrence of secondary bacterial complications, etc.

Prevention of leptospirosis

Nonspecific prophylaxis is carried out jointly by Rospotrebnadzor and veterinary services through the identification and treatment of sick animals, the regular deratization of populated areas, the protection of reservoirs from contamination by sick animals and the disinfection of water.

Consultation of a physician:

Question: Is a person with a leptospirosis dangerous for others?
Answer: no, because it is a biological impasse in the spread of infection, although the risk remains, albeit minimal.

Question: Is there any immunity after the transferred disease?
Answer: yes, long enough( possibly lifelong), but strictly type-specific. Ie, if the infection occurs by some other serovar Leptospira, then a re-infection is possible.

Therapist doctor Shabanova I.Е.