Langford MP, Sebren AR, Burch MA, et al. - Using human corneal epithelial cells (HCEC), researchers sought to examine the antiviral activity of methylene blue (MB; a WHO essential medicine) against acute hemorrhagic conjunctivitis (AHC) viruses. Time and concentration-dependent MB accumulation by HCEC was colorimetrically determined and MB inhibition of virus production of 5 E70 and 3 CA24v AHC epidemic isolates in HCEC was determined through micro-plaque assay. MB uptake by HCEC has been rapid and concentration dependent. The results indicate that MB treatment before and shortly after infection will inhibit the production of AHC virus and caspase-mediated HCEC cytopathy. The findings support the therapeutic potential of MB-containing ophthalmic solutions against AHC virus infection during epidemics.