Leptospirosis

Leptospirosis (Vasiliev-Weil disease, infectious jaundice, Japanese 7-day fever, nannukai, water fever, ikterogemorragicheskaya fever, etc.) - a general term for all infections caused by bacteria of the genus Leptospira regardless of the serotype; includes infectious, or leptospiroznuyu, jaundice and canine fever. Symptoms of leptospirosis are biphasic. Both phases include episodes of fever, in the second phase can sometimes be hepatitis, meningitis and kidney damage. The diagnosis is based on the detection of leptospira in a dark field bacteriologically and serologically. Treatment of leptospirosis is carried out by doxycycline and penicillin.

ICD-10 codes

• A27.0. Leptospirosis is icterous-hemorrhagic.
• A27.8. Other forms of leptospirosis.
• A27.9. Leptospirosis, unspecified.

The first description of the disease, called fievre jaune ("yellow fever"), was given in 1812 by the military doctor Larrey, who observed patients from Napoleon's detachments during the siege of Cairo. The disease for a long time was called Weil-Vasiliev's disease, since the first clinical descriptions of leptospirosis as an independent nosological form were given by A. Weil in Heidelberg (1886) and N.P. Vasilyev in Russia (1888). In 1907 the causative agents of the disease - spiral microorganisms - were first detected with the help of special methods of staining with postmortem examination of the human kidney (Stimson, USA). In 1915, simultaneously a group of German doctors (Ulengut NR et al.) And Japanese researchers (Inada R., before V. Et al.) Isolated pathogens from sick people - German soldiers who fought in northeastern France (" French disease "), and Japanese miners. The term "leptospira" (soft, gentle spiral) belongs to the microbiologist Noguchi (Japan, 1917). Later it became known that the pathogens have many serovars that cause lesions in humans. In the 20s of the last century, the epidemiological role of animals as sources of human infection - rats, dogs, livestock was revealed.

What causes leptospirosis?

Leptospirosis is a zoonosis; infection occurs in many domestic and wild animals both in severe lethal form and in the form of bacterial carry. In the latter case, pathogens are excreted in the urine of the animal for many months. A person becomes infected by direct contact with the urine or tissues of a sick animal or indirectly through contaminated water and soil. Usually, the skin of the skin and mucous membranes (oral cavity and nose, conjunctiva) become the gate of the infection. Leptospirosis can be an occupational disease (from farmers, slaughterhouse workers and other agricultural enterprises), but in the US, most cases are related to resting (in particular, swimming in polluted water). Often the source of infection are dogs and cats. Of the 40-100 cases recorded annually in the US, the bulk falls at the end of summer - the beginning of autumn. Due to the lack of clarity of clinical symptoms, it is possible that many more cases remain unidentified and unaccounted for.

What are the symptoms of leptospirosis?

Leptospirosis has an incubation period that lasts from 2 to 20 days (usually 7-13). There are two phases of the disease. The septicemic phase begins with a sudden chill, a fever, a headache, and severe muscle pains. In 2-3 days there is a hyperemia conjunctiva. The liver and spleen are rare. This phase lasts 4-9 days; the temperature occasionally rises to 39 C or more, chills are repeated. After the temperature drops, on the 6th-12th day of the disease, the second, or immune, phase begins, coinciding with the appearance of specific antibodies in the blood. The symptoms and fever described above resumed, and signs of meningitis may appear. Iridocyclitis, neuritis of the optic nerve, peripheral neuropathy are occasionally noted. If infection occurs during pregnancy, leptospirosis can cause abortion, even at the stage of recovery.

Weil disease (leptospirotic jaundice) is a severe form of leptospirosis with jaundice associated with intravascular hemolysis, azotemia, anemia, hemorrhages, impaired consciousness and continuous fever. Hemorrhagic phenomena are associated with the defeat of the capillary walls and include nasal bleeding, petechiae, purpura, ecchymosis, followed by development and rare progression to subarachnoid hemorrhages, adrenal hemorrhages and gastrointestinal hemorrhages. Signs of hepatocellular and renal dysfunction appear after 3-6 days. The pathology of the kidneys includes proteinuria, pyuria, hematuria and azotemia. Thrombocytopenia is possible. Lesions of the liver are insignificant and on the recovery of its functions are completely restored.

With anicteric form of the disease, the lethality is zero. If jaundice develops, lethality reaches 5-10%, and at the age of over 60 years can be higher.

How is leptospirosis diagnosed?

Symptoms of leptospirosis may be similar to those of viral meningoencephalitis, other infections caused by spirochetes, influenza and hepatitis. The presence in a history of biphasic fever helps in the diffodiagnosis of leptospirosis. Leptospirosis should be borne in mind in all cases of fever of unknown origin (LDL) in persons who were in epidemiological conditions with a risk of infection with leptospira.

In patients with suspected leptospirosis, a culture of blood should be taken, the antibody titer determined in the acute period and in the recovery period (3-4 weeks), a general blood test, biochemical analysis and hepatic tests performed. If there are meningeal symptoms, a spinal puncture should be performed; the number of cells in the cerebrospinal fluid is 10-1000 / μL (usually less than 500 / μL with a predominance of mononuclear cells). The glucose content remains normal, the protein level does not exceed 100 mg / dl.

The number of white blood cells in the blood remains normal or slightly increased, but in severe form it can reach 50,000 / μL. The prevalence of neutrophils (more than 70%) makes it possible to distinguish leptospirosis from viral infections. The content of bilirubin in the blood is usually less than 20 mg / dL (less than 342 μmol / L), but can reach 40 mg / dl (684 μmol / L) in severe conditions; with jaundice, there is intravascular hemolysis, leading to severe anemia.

How is leptospirosis treated?

Antibacterial treatment of leptospirosis is quite effective, even if it is started late. In severe cases, penicillin G IV is recommended from 5 to 6 million units / day after 6 hours or ampicillin intravenously at 500-1000 mg every 6 hours. In non-severe cases, antibiotics may be given orally - doxycycline 100 mg twice daily, ampicillin 500-750 mg every 6 hours or amoxicillin 500 mg every 6 hours for 5-7 days. In severe cases it is also important to maintain the water and electrolyte balance. Isolation of the patient is not necessary, but it is necessary to follow the appropriate measures to control diuresis.

Doxycycline 200 mg once a week is used for prevention in endemic areas.

How to prevent leptospirosis?

Leptospirosis can be prevented if identification and treatment of leptospirosis in valuable animals is carried out, regular deratization of populated areas, protect reservoirs from contamination with animal excreta, prohibit bathing in inactive reservoirs, disinfect water and; open water sources, fight stray dogs.

Vaccination of farm animals and dogs, planned vaccination of persons, whose work is associated with the risk of infection with leptospirosis: workers of livestock farms, zoos, pet stores, dog nurseries. Livestock farms, enterprises for processing livestock raw materials, laboratory staff working with Leptospira cultures. The vaccine against leptospirosis is introduced for the prevention of leptospirosis from the age of 7 in a dose of 0.5 ml subcutaneously once, revaccination in a year.