We describe an autochthonous case of Rickettsia slovaca infection in a man 35 years of age from Russia who had tickborne lymphadenopathy. We used ELISA and quantitative PCR testing to further identify DNA and confirm diagnosis. Physicians in Russia should consider similar diseases in differential diagnoses after tick bites.

The most severe manifestation of the new coronavirus infection COVID-19 in children is the multisystem inflammatory syndrome in children (MIS-C). A systematic review of foreign publications as of July 25, 2020 contains an analysis of the disease course in 662 children with this syndrome and is used for comparison with the data obtained. Objective of the research: to characterize clinical manifestation, results of laboratory and instrumental studies, therapy, outcomes and consequences of the COVID-19- associated MIS-C, based on the observation of patients hospitalized to Morozov Children's City Clinical Hospital and Children’s clinical hospital of infectious diseases № 6 from May 1 to September 15, 2020. Materials and methods: the pilot study included 32 children aged 9 months – 15 years with COVID-19-associated MIS-C, verified based on WHO criteria (2020), including symptoms of Kawasaki disease (KD), arterial hypotension/shock, laboratory and instrumental signs of heart damage, signs of coagulopathy, gastrointestinal symptoms, increased inflammation markers, COVID-19 markers. Results: the median age of patients was 6 years, boys predominated among the patients (66%), all patients had antibodies to SARS-CoV-2 (31 children of the IgG class); MIS-C manifested itself as a combination of KD symptom complex (75% of patients) with arterial hypotension/shock (28%), neurological (50%), respiratory (41%), gastrointestinal (59%) symptoms; macrophage activation syndrome (MAS) was verified in 16% of patients. Therapy included intravenous immunoglobulin (75%), systemic glucocorticosteroids (88%), anticoagulants (91%), vasoactive/vasopressor support (31%). In 38% of cases treatment was performed in intensive care unit; one child died. According to echocardiography, 16% of patients had coronariitis, ectasia, and coronary arteries aneurysms. Conclusion: COVID-19-associated MIS-C is characterized by a severe course, cross-features with KD, shock syndrome with KD, MAS which requires intensive therapy and can cause acquired pathology of the cardiovascular system in children.

A case of Tick-borne spotted fever in a child after a visit to an endemic region, the Republic of Crimea, is described. The disease caused difficulty in terms of clinical diagnosis, which led to the delayed prescription of specific therapy with doxycycline. The diagnosis of Тick-borne spotted fever was made on the basis of detectingR. conoriiDNA in a washout with primary affect. In the course of the disease, IgM class antibodies were detected during serological analysis of paired serum.

We represent a rare clinical case of infectious mononucleosis with hepatitis, caused by Epstein-Barr virus, complicated by rare secondary autoimmune hemolytic anemia associated with warm agglutinins in a 16-year-old patient. The disease was long-lasting, with a two-wave course of febrile fever. Signs of hepatitis with the development of anemia of moderate severity appeared during the second wave of febrile fever. The etiology of the disease was confirmed by the detection of Epstein-Barr virus DNA in blood and the detection of anti-VCA IgM antibodies to Epstein-Barr virus in the absence of anti-EBNA IgG antibodies. Hemolytic anemia was verified using markers of hemolysis (increased lactate dehydrogenase activity, decreased haptoglobin concentration), and positive results of a direct Coombs test. After successful initiation of prednisone therapy and clinical improvement, the patient was discharged from the hospital on the 24th day of disease to continue treatment on an outpatient basis (prednisone was replaced by methylprednisolone).This case demonstrates the development of a rare autoimmune complication in infectious mononucleosis caused by the Epstein-Barr virus.

Timely diagnosis of Lyme-borreliosis (LB) is the key to its successful treatment. Outpatient monitoring of patients after tick bite based on the algorithm is able to optimize the early diagnosis of LB, shorten the start of treatment and improve the disease surveillance.Purpose. Creation of an algorithm for monitoring patients after tick bite for use in outpatient settings by primary care physicians. Material and methods. A retrospective, non-randomized, single-center cohort study was conducted based on the analysis of data from 660 outpatient records of patients consulted by an infectious disease specialist in the Infectious clinical hospital No.1 in Moscow. Patients were divided by age and the presence or absence of a diagnosis of LB. Confirmation of the diagnosis was carried out according to clinical and/or laboratory criteria using methods of enzyme-linked immunoassay and immune blot. Results. The analysis of the results of enzyme immunoassay of antibodies to borrelia in patients with LB was carried out. The optimal sampling time was 7 or more weeks from the moment of tick bite and 4 or more weeks from the moment of onset of symptoms. The specificity of immunological diagnostics in patients with excluded LB was evaluated. The proportion of doubtful and false positive results in such patients was high — 28.1%. False positive results were more common in adults (37.6%) compared with children (9.8%), which is associated with more frequent false positive results of IgM determination (34.1% in adults, 4.9% in children). Based on the data of our study, an algorithm for monitoring patients after tick bite has been developed, focused on use in outpatient settings by primary care physicians.

The detection of antibodies to borrelia by enzyme immunoassay (ELISA) significantly depends on the time from the onset of the disease.Purpose: analysis of the results of antibodies determination to borrelia by ELISA in children and adults with Lyme borreliosis (LB) at various periods from the onset of the disease.Material and methods. We conducted a retrospective, non-randomized, single-center cohort study, based on the analysis of data from 178 outpatient records of patients with a confirmed diagnosis of LB and the presence of antibody detection results by ELISA. Immunological confirmation of the diagnosis of LB was carried out by using ELISA and western blot test systems registered in the territory of the Russian Federation for the separate determination of immunoglobulins to Borrelia burgdorferi antigens of classes M and G. Results. When counting from the date of the onset of the disease, IgM and/or IgG were determined in 76% of patients at 4-6 weeks, and starting from the 7th week – in 95%. When counting from the date of tick bite, IgG with or without IgM was determined in 83% of patients starting from 7th week. At the same time, a significantly large proportion of seronegative patients among children was revealed. We have clarified the duration of antibody persistence after antibacterial therapy. In the interval from 1 to 6 months, antibodies are detected in 73% of patients. For a period of 6 months or more, antibodies can be detected in 42% of patients.Conclusion. The optimal time for detecting antibodies from the disease onset is 4-6 weeks. Antibodies after antibiotic therapy can persist for a long time, in a third of patients up to 6 months or more.