Scientists detect replication-competent Oropouche virus in semen of traveler, sparking transmission fears

New findings reveal the presence of replication-competent Oropouche virus in semen, posing recent questions on sexual transmission dangers and public well being security.

Analysis Letter: Replication-Competent Oropouche Virus in Semen of Traveler Returning to Italy from Cuba, 2024. Picture Credit score: CI Images / Shutterstock

In a latest examine revealed within the journal Emerging Infectious Diseases, researchers on the College of Brescia, Brescia, Italy, investigated the presence of replication-competent Oropouche virus (OROV) (an arbovirus inflicting flu-like sickness, transmitted by biting midges and mosquitoes) within the semen of a traveler identified with Oropouche fever, highlighting potential dangers for sexual transmission.

Background

OROV is an rising zoonotic arbovirus from the Simbu serogroup of the genus Orthobunyavirus, household Peribunyaviridae. Its pure hosts embrace nonhuman primates, some wild birds, and pale-throated sloths. OROV is primarily transmitted by biting midges, akin to Culicoides paraensis and Culex quinquefasciatus mosquitoes. Symptomatic Oropouche fever resembles an influenza-like sickness, with attainable self-limiting meningitis or meningoencephalitis (irritation of the mind and its protecting membranes). Whereas endemic to the Amazon Area, over 9,852 confirmed Oropouche circumstances have been reported in Brazil, Bolivia, Peru, Colombia, Cuba, and the Dominican Republic as of September 2024. Additional analysis is required to grasp the implications of OROV, notably relating to vertical transmission and antagonistic being pregnant outcomes.

Concerning the Examine

In August 2024, a 42-year-old man from Italy was evaluated for acute febrile sickness after coming back from Cuba, the place he traveled from July 19 to 29. He skilled excessive fever, headache, and basic malaise shortly earlier than his return, with signs reemerging 4 days after onset. Scientific evaluations indicated no meningeal irritation, rash, or lymphadenopathy (swollen lymph nodes).

Laboratory checks yielded adverse outcomes, together with blood cultures and particular real-time reverse transcription polymerase chain response (RT-PCR) for different arboviruses. Nevertheless, Oropouche fever was confirmed by two OROV-specific RT-PCRs, with constructive leads to serum, complete blood, and urine collected 4 days post-symptom onset. Extended viral ribonucleic acid (RNA) shedding was famous in blood and urine samples, whereas recent semen samples revealed increased OROV RNA ranges. Notably, infectious OROV was cultured from the semen below Biosafety Degree 3 situations, confirming replication competence.

Examine Outcomes

The analysis of the 42-year-old man revealed important medical findings associated to OROV an infection. Upon his admission to the Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Sacro Cuore Don Calabria Hospital on August 2, 2024, he offered with an acute febrile sickness that started shortly after coming back from Cuba. Initially, the affected person skilled a excessive fever of 39.0°C, headache, and basic malaise. Though his fever subsided after two days, it recurred 4 days after symptom onset, however his neurologic examination remained unremarkable all through.

Laboratory investigations confirmed a leukocyte depend inside regular reference limits and no indicators of thrombocytopenia (low platelet depend within the blood). Blood cultures returned adverse outcomes, and particular RT-PCR assays for dengue, chikungunya, and Zika viruses had been additionally adverse. Nevertheless, Oropouche fever was identified by two OROV-specific RT-PCRs concentrating on the small genomic section, confirming the virus’s presence in complete blood, serum, and urine samples collected on day 4 of symptom onset. The affected person demonstrated medical enchancment and was symptom-free by day ten.

On days ten, sixteen, and thirty-two after symptom onset, RT-PCR outcomes indicated persistent OROV RNA in complete blood and urine. Whereas serum samples had been constructive for OROV RNA on day ten, they had been adverse on day sixteen, suggesting a lower in viral load. Notably, recent, unfractionated semen samples collected on days sixteen, thirty-two, and fifty-eight constantly confirmed increased viral RNA ranges than these present in urine and complete blood. The cycle threshold (Ct) values for the semen samples had been 25.4 on day sixteen, 28.9 on day thirty-two, and 34.1 on day fifty-eight, indicating ongoing viral shedding.

On day sixteen, infectious OROV was remoted from the semen pattern utilizing cell tradition strategies below Biosafety Degree 3 situations. This isolation was confirmed by the statement of clear cytopathic results (CPE) after 5 days and a marked improve in OROV RNA ranges within the spent cell progress medium. Though viral RNA shedding continued to be increased in semen in comparison with urine and complete blood on day thirty-two, the flexibility to display replication competence had ceased by this time.

Conclusions

To summarize, the examine highlights the extended shedding of OROV RNA in a number of physique fluids, notably in semen, with the detection of replication-competent virus in a affected person returning to Italy from Cuba. These findings increase important issues relating to the potential for sexual transmission of OROV. Nevertheless, the examine authors warning that the medical relevance of those findings stays unsure, as replication-competent virus was solely detectable early within the an infection, and extra information are wanted. The implications for public well being are noteworthy, notably within the context of sperm banking and assisted reproductive applied sciences. Additional longitudinal research are required to determine how steadily infectious OROV could also be shed in semen and its potential dangers in sexual transmission.