Dengue Virus Dynamic and Persistence in Body Fluids of Infected Patients in Italy, 2018–2023

Dengue, a mosquito-borne disease caused by the dengue virus (DENV), is constantly expanding worldwide. We investigated the presence and persistence of DENV RNA in the bloodstream and other body fluids to describe the viral kinetics in the human host. We longitudinally collected serum (n = 118), plasma (n = 110), whole blood (n = 90), urine (n = 118), oral swabs (n = 68), saliva (n = 42), semen (n = 23), and vaginal fluids (n = 49) from 42 DENV patients. We measured DENV RNA for a median of 28 (range 1-63) days from symptom onset (DSO). We estimated the probability of viral detection applying a generalized linear model, and the duration of viremia using Monte Carlo-Markov Chain approach. In the bloodstream, the highest rate of positivity, levels of DENV RNA, and persistence were observed in whole blood. The estimated probability of a positive test dropped below 5% after 12.5, 20.7, and 35.4 DSO for plasma, serum, and whole blood, respectively. The average duration of viremia was estimated to be 19.9 DSO. Saliva and oral swabs showed 76.2% and 58.8% of DENV RNA positivity during the first week of symptoms while the longest persistence was observed in urine (39 DSO). DENV was revealed in 20% cervicovaginal (up to 11 DSO) and 30% seminal (up to 35 DSO) fluids. Whole blood represents the preferential specimen for dengue molecular detection and the correct estimation of viremia duration which have clear implications for onward transmission and public health countermeasures. Blood, urine, and oral samples can be assayed according to time from disease onset, severity, and screening purposes.