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Diagnosis of leptospirosis
Last reviewed: 23.04.2024
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Diagnosis of leptospirosis is based on the study of epidemics. It is necessary to take into account the profession of the patient (agricultural worker, hunter, veterinarian, deratigator), as well as contact with wild and domestic animals. It should be noted whether the patient bathed in open reservoirs, since the seeding of water by leptospira in certain regions is extremely large.
The diagnosis of leptospirosis is established on the basis of the characteristic clinical symptoms: acute onset, hyperthermia, myalgia, face hyperemia, combined liver and kidney damage, hemorrhagic syndrome, acute inflammatory changes in the blood.
Laboratory diagnostics of leptospirosis
Laboratory diagnosis of leptospirosis involves the use of bacterioscopic, bacteriological, biological and serological studies. In the early days of the disease, leptospires are found in the blood with the help of darkfield microscopy, later in the sediment of urine or spinal fluid.
When sowing blood, urine or spinal fluid on nutrient media containing serum, it is possible to obtain more reliable results, although this method takes time, as, as already mentioned, the leptospira grow quite slowly. Primary cultures of blood, urine, and tissues of organs suspected of maintaining leptospira are recommended to withstand the first 5-6 days at a temperature of 37 ° C, and then at 28-30 ° C.
The biological method is to infect animals: mice, hamsters and guinea pigs, but recently this method has many opponents who consider it inhumane.
The most informative are serological methods, in particular the microagglutination reaction recommended by WHO. Positive is believed to increase the titer of antibodies 1: 100 and above. Use also RAL leptospira in the Dutch version. Antibodies appear late, not earlier than the 8-10th day of the disease, so it is advisable to examine the paired sera taken at intervals of 7-10 days.
Differential diagnosis of leptospirosis
Differential diagnosis of leptospirosis is carried out with viral hepatitis and other infectious diseases, in which jaundice is observed (malaria, yersiniosis). Unlike viral hepatitis, leptospirosis begins acutely, with a high temperature, against which jaundice occurs. The patient can call not only the day, but also the hour of illness. With icteric forms of leptospirosis, an increasing anemia is characteristic. Against the background of jaundice, hemorrhagic syndrome develops and the phenomena of renal insufficiency. In the presence of meningeal syndrome it is necessary to differentiate leptospirosis meningitis from serous and purulent meningitis of another ethnology, in the presence of hemorrhagic syndrome - from hemorrhagic fever, with renal insufficiency - from HFRS.
Differential diagnosis of leptospirosis with anicteric forms is performed with influenza, rickettsiosis.