Mathematical modeling of differential diagnosis of tick-borne infections in children

Abstract

Objective: to study the anamnestic and clinical-laboratory features of the course of tick-borne infections in hospitalized patients aged 2 to 14 years with an assessment of their prognostic ability. 
Materials and methods. The study involved 66 children aged 2 to 14 years, hospitalized for tick-borne encephalitis (TBE) or ixodid tick-borne borreliosis. We studied the anamnesis, carried out a set of serological and molecular biological methods to assess the specific immune response of patients and tick infestation. 
Results. In the group of children with tick-borne encephalitis, the meningeal form of the disease was established in 74.3% (26/35) of children, febrile in 17.1% (6/35), inapparent in 5.7% (2/35) and subclinical in 2.9% (1/35) of children. In children with tick-borne borreliosis, the erythema form of the disease was noted in 58% (18/31) of patients, while the remaining 42% (13.31) had a non-erythema form. It was found that the time period from the tick bite to the onset of clinical manifestations did not have reliable differences in the groups: in patients with tick-borne encephalitis it was 14 days (IQR 4.5; 17), and in patients with tick-borne borreliosis — 12 days (IQR 6.5; 16), p = 0.670. A history of tick bite in the anamnesis was noted in 59/66 cases (89.3%), but a tick study using PCR was performed only in 25/66 (37.8%) people: in 14/25 (56%) cases, RNA of the tick-borne encephalitis virus was detected, in the remaining cases — exclusively Borrelia DNA or a combination of pathogens. Mathematical modeling has determined prognostic criteria that determine with high probability the course of tick-borne encephalitis in a patient: leucocyte, neutrophils, lymphocytes blood count, the values of the enzymes ALT and AST. 
Conclusions. A formula has been obtained that is a convenient tool for rapid assessment of the risk of tick-borne encephalitis, based exclusively on laboratory data. This is especially relevant in endemic regions where rapid differentiation of TBE from other tick-borne infections, such as ixodid tick-borne borreliosis.