Background
Since May 2022, over 27,000 cases of monkeypox (MPOX) have been reported in Europe where the disease is not endemic. In the Democratic Republic of Congo (DRC), this disease has become a public health emergency, with 19,667 suspected cases and 575 deaths reported in 2024. Monkeypox virus (MPXV) represents a diagnostic challenge due to the diversity of clinical presentations. These symptoms often share similarities with infection caused by herpes simplex virus (HSV) types 1 and 2 and varicella-zoster virus (VZV). AFYIA Diagnostics has developed a qualitative screening test that allows the simultaneous identification of these viruses.
Methods
The DIRASH kit is a multiplex HRM assay, based on the simultaneous detection of 4 viruses. The associated DISoft™ software is used to automatically analyze and interpret the HRM profiles obtained. Three studies were carried out to monitor cases of cutaneous-mucosal febrile vesicular eruptions: 1 conducted by CHU Montpellier from January 2021 to December 2022 during the clade II epidemic, and 2 conducted by INRB in Kinshasa from December 2022 to June 2024 with clade Ia and Ib . Each patient was screened by commercial or in-house PCRs. These samples were then retrospectively tested with the DIRASH.
Results
850 samples were retrospectively tested with the DIRASH kit to compare its clinical sensitivity with that of partner laboratory kits. In Montpellier, sensitivity was 100% for MPXV, 94% for VZV, and 98% for HSV-1 and HSV-2. INRB reported 98% for MPXV and 93% for VZV, showing the DIRASH kit ability to detect clades Ia, Ib, and II. This kit detected several undiagnosed co-infections (MPXV/HSV-1, MPXV/HSV2 and MPXV/VZV), with a consistent specificity of 100%. These results show that the clinical sensitivity of the PCRs from CHU and INRB is comparable to that of the DIRASH kit, with additional co-infections detected by the DIRASH kit, that would have been missed with the other PCRs, highlighting the benefit of syndromic diagnosis for febrile rashes.
Conclusions
The DIRASH kit is rapid, reliable, transportable at room temperature, low-cost-multiplex test with automated result interpretation. Its ability to simultaneously detect viruses causing mucocutaneous vesicular eruptions meets the needs for differential diagnosis of MPXV, particularly in the DRC, where the epidemic is the largest in Africa, but also non-endemic countries. The kit is well-suited to strengthening diagnostic capabilities in the DRC, supporting patient management and epidemic control.