Detecting the presence of serum IgG in patients with crimean-congo hemorrhagic fever

Aim: The aim of our study was to determine the presence of serum IgG in people who had Crimean-Congo Haemorrhagic Fever (CCHF), to evaluate how demographic characteristics, history of tick contact, history of replacement therapy during the period of the disease, clinical course of the disease, whether they paid attention to prevention measures in risky situations after the disease, whether the people in their close environment had CCHF disease affected the CCHF IgG antibody status and to determine how long the CCHF IgG antibody remained positive in serum. Material and Method: A total of 155 people were included in the study, including 153 people who were treated and discharged with a diagnosis of CCHF disease between 2011 and 2021 at the Infectious Diseases and Clinical Microbiology Clinic of Hitit University Faculty of Medicine Erol Olçok Training and Research Hospital, and a health worker who was followed up in 2009 in Ankara due to CCHF, and two people who were admitted to our clinic for other reasons and who we learnt had a history of hospitalisation in Ankara due to CCHF in 2007. Sera obtained from the patients were stored at -80 C for later study. A structured questionnaire consisting of 13 questions was applied to the individuals. The severity of the disease was determined using the Severity Scoring Index (SSI). The presence of CCHF IgG antibody was analysed by ELISA method. The results obtained were statistically analysed according to the years of illness and the questions asked in the questionnaire. Statistical significance level was accepted as p<0.05. Results: In our study, CCHF IgG antibody was found positive in 47 (30.3%) individuals. It was observed that the positivity rate was high if the duration of the disease was 7 years and decreased if the duration was 8 years. No significant difference was found in CCHF IgG antibody status according to the year of the disease, demographic characteristics, history of tick contact, history of replacement therapy during the disease, clinical course of the disease, attention to preventive measures in risky situations after the disease, and CCHF disease in close relatives. The age of people who were CCHF IgG positive was significantly higher than those who were negative at the time of the disease (p=0,043). Conclusion: Our findings suggest that the presence of CCHF IgG in people who have had CCHF disease remains around 7 years on average. CCHF IgG positivity is increased in those with a higher average age at the time of CCHF infection CCHF IgG positivity can be used as a screening test in epidemiological studies as it indicates that the disease has been transmitted in the past. However, since CCHF IgG positivity alone cannot be used to show the immune status, further studies are needed to show whether these antibodies have neutralising properties to protect against the disease in individuals with IgG positivity. Key words: CCHF, CCHFV, IgG antibody, Immunology