We report a case of reinfection by SARS-CoV-2 with the second virus harboring amino acid changes in the Spike protein (141-143del, D215A, ins215AGY, L452R, D614 G), orf1a, helicase, orf3a, and Nucleocapside. The virus associated with the reinfection, from an endemic lineage containing the S:L452R immune escape mutation, was circulating in Panama at the time.

There is limited evidence regarding severe acute respiratory syndrome coronavirus 2 infection in the placenta of pregnant women who tested positive, and if this could be a route for vertical transmission of the virus in utero. We present the cases of 2 pregnant women in their third trimester who were admitted for delivery by cesarean delivery and who, through universal screening, tested positive for coronavirus disease 2019. The maternal and fetal sides of the placenta were sectioned from both patients for viral analysis. Real-time polymerase chain reaction analysis of the placental-extracted RNA revealed a severe acute respiratory syndrome coronavirus 2 infection on the fetal side of the placenta in both patients. The virus was isolated from the patient with the lowest cycle threshold value on the fetal side of the placenta. Whole genome sequencing showed that the virus detected in this placenta was from the B1 lineage. Immunohistochemical analysis of the placental tissue detected severe acute respiratory syndrome coronavirus 2 in the endothelial cells of chorionic villi vessels proximal to both the maternal and fetal sides, with a granular cytoplasmic pattern and perinuclear reinforcement. Histologic examination of the placenta also detected a dense infiltrate of lymphoid cells around decidual vessels and endothelial cells with cytopathic changes, especially on the maternal side. Nasopharyngeal swabs from the infants that were subjected to reverse transcription quantitative polymerase chain reaction testing were negative for severe acute respiratory syndrome coronavirus 2 at 24 hours after birth. A follow-up analysis of the infants for immunoglobin G and immunoglobin M expression, clinical manifestations, and long-term developmental abnormalities is recommended.

Background/Objectives: Arboviruses including dengue virus (DENV), Zika virus (ZIKV), chikungunya virus (CHIKV), yellow fever virus (YFV), and West Nile virus (WNV) co-circulate across the Americas, generating overlapping febrile syndromes that challenge etiological diagnosis based solely on clinical criteria. Cartridge-based multiplex molecular platforms offer potential for decentralized testing in hyperendemic settings, yet independent real-world evaluations of their clinical and analytical performance remain limited. Methods: A retrospective two-phase analytical study was conducted. Phase 1 assessed clinical diagnostic accuracy for dengue using 163 de-identified serum samples classified using a composite reference standard consisting of Panbio NS1 ELISA reactivity (≥11 Panbio units) combined with compatible clinical and epidemiological data, operationalized in accordance with the PAHO 2023 laboratory confirmation algorithm for dengue; RT-qPCR was not routinely available for all archived samples, and reported sensitivity should therefore be interpreted as a conservative lower-bound estimate; Phase 2 evaluated analytical sensitivity across all eight panel targets using characterized arboviral reference strains in serial dilution experiments, with reference RT-qPCR assays as the comparator; this phase was incorporated to characterize detection thresholds for targets not represented by clinical specimens. Results: In Phase 1, the M10 demonstrated sensitivity of 96.0% (96/100), specificity of 100% (63/63), overall accuracy of 97.5%, and near-perfect agreement with the reference standard (Cohen’s κ = 0.95). DENV-3 was the predominant serotype (74/96; 77.1%), followed by DENV-1 (16.7%) and DENV-4 (6.3%); DENV-2 was not detected. In Phase 2, operational LoDs (defined as the lowest concentration yielding a detectable Ct in all triplicate reactions for the RT-qPCR, and from a single cartridge per dilution point for the STANDARD M10) were equivalent or superior to reference RT-qPCR for six targets (DENV-1, DENV-3, DENV-4, ZIKV, WNV, YFV; range 1–5 PFU/mL), while DENV-2 and CHIKV showed 20-fold higher operational LoDs (20 PFU/mL vs. 1 PFU/mL for the reference RT-qPCR); formal LoD₉₅ estimates were not determined. Conclusions: The STANDARD M10 Arbovirus Panel shows high clinical accuracy for dengue and adequate analytical sensitivity for most targets, supporting its use as a complementary decentralized molecular tool. Reduced sensitivity for DENV-2 and CHIKV and the absence of formal LoD₉₅ estimates remain key limitations to be addressed in future validation studies.