Beyond tick-bites: a healthcare-associated transmission alert for severe fever with thrombocytopenia syndrome in family caregivers

This study aimed to investigate and evaluate the epidemiological characteristics, transmission chains, and effectiveness of control measures for two clusters of Severe Fever with Thrombocytopenia Syndrome (SFTS) infections in Jinan City, China, to inform and strengthen future SFTS prevention and control strategies. Field epidemiological investigations were conducted, encompassing all identified cases, which included confirmed cases (n = 4) and a clinically diagnosed case (n = 1), along with their close contacts (n = 11). The response strategy involved serological testing of close contacts and monitoring the SFTSV carriage rate in host animals and vector ticks. Two clusters of SFTS infection occurred in rural areas of Jinan in June 2025, involving four laboratory-confirmed and one clinically diagnosed case (two males and three females; case fatality rate: 20.0%). All five cases initially presented with fever (> 38 °C) and thrombocytopenia. Two patients experienced vomiting, and two had underlying diseases. The mean duration from symptom onset to initial medical consultation was three days, with an average of 2.2 healthcare referrals. Tick density monitoring in rose fields near the patients’ residences revealed an average free-tick density of 0.4 ticks per 100 flagging meters per hour, with all specimens identified as Haemaphysalis longicornis. No parasitic ticks were detected on captive goats, and all animal samples tested negative for SFTSV. Epidemiological investigations confirmed clear transmission links among all cases within the two clusters, indicating that infections resulted from direct contact with the blood or secretions of confirmed cases. Unprotected direct contact with the blood or bodily secretions of infected individuals poses a significant risk for SFTSV transmission and the subsequent occurrence of SFTS clusters. Strengthening infection control practices is therefore essential in all healthcare and caregiving settings through strict adherence to standard precautions, including the appropriate use of personal protective equipment and safe handling of body fluids.