Diagnostic delay inducing severe imported falciparum malaria: a time-sensitivity comparison of two imported cases during COVID-19 co-circulation.

BACKGROUND

The COVID-19 pandemic created novel diagnostic challenges for imported malaria due to overlapping symptoms and prioritized SARS-CoV-2 screening. This report presents a critical comparative analysis demonstrating how diagnostic delays during co-circulation directly impact malaria severity-an underreported phenomenon with significant clinical implications.

CASE PRESENTATION: Two male patients returning from Africa (Nigeria and Côte d'Ivoire) developed fever during mandatory COVID-19 quarantine in Shanghai, China (2021). Both initially tested negative for SARS-CoV-2. Case 1 experienced a 96-h diagnostic delay, progressing to severe falciparum malaria with delirium, thrombocytopenia (33 × 10⁹/L), and acute kidney injury (creatinine 278 μmol/L), requiring intensive care. Case 2 was diagnosed within 24 h via rapid diagnostic test and microscopy, receiving immediate artesunate treatment without severe complications.

CONCLUSIONS

Diagnostic delay directly impacts severe malaria risk during COVID-19 co-circulation. Parallel testing for both pathogens in febrile travelers from endemic areas is critical. The proposed "48-Hour Three-Tier Diagnostic Response System" should shorten the diagnostic window.