Diagnostic performance of clinical symptom combinations for Crimean-Congo hemorrhagic fever in emergency department patients with reported arthropod bites, stings, or exposure

Background: Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal tick-borne viral disease that remains an important public health problem in endemic regions. Early recognition of CCHF in emergency departments is challenging because initial clinical manifestations are often nonspecific. This study aimed to evaluate the demographic, clinical, and exposure-related characteristics of adult patients presenting to the emergency department after reported or clinically suspected arthropod bites, stings, or contact and to investigate clinical predictors associated with CCHF. Methods: This retrospective single-center study included adult patients presenting to the emergency department after reported or clinically suspected arthropod bites, stings, or contact between October 1, 2023, and October 1, 2024. A total of 526 patients were screened; 24 patients with incomplete data and 2 patients younger than 18 years were excluded. Demographic characteristics, clinical symptoms, and history of tick exposure were recorded. Clinical findings associated with CCHF were analyzed using univariable and multivariable statistical methods. The diagnostic performance of symptom combinations with tick exposure was evaluated using sensitivity, specificity, predictive values, likelihood ratios, odds ratios, and relative risks. Results: A total of 500 adult patients were included, and CCHF was confirmed in 38 patients (7.6%). The mean age was 49.48 ± 15.91 years, and 62.8% of the patients were male. Fever, headache, diffuse body aches, malaise, nausea/vomiting, diarrhea, abdominal pain, rash, ecchymosis, and history of tick exposure were significantly more frequent in CCHF-positive patients (all p < 0.05). CCHF positivity was significantly higher among patients with a history of tick exposure than among those without tick exposure (11.9% vs 3.8%; OR: 3.45, p = 0.001). Among symptom combinations evaluated with tick exposure, diffuse body aches showed the highest specificity (100.0%) and a very high positive likelihood ratio after continuity correction; however, these estimates should be interpreted cautiously because no CCHF-negative patient had this combination. In multivariable logistic regression analysis, malaise (adjusted OR: 117.29, 95% CI: 28.23–487.33, p < 0.001) and fever (adjusted OR: 6.41, 95% CI: 1.87–21.94, p = 0.003) were independently associated with CCHF. Conclusion: Simple clinical findings and symptom combinations may provide valuable early diagnostic clues for CCHF in endemic regions, even before laboratory confirmation. In particular, malaise and diffuse body aches in patients with a history of tick exposure showed high diagnostic performance and may contribute to early recognition and appropriate management of CCHF in emergency department settings. © The Author(s) 2026.