The feasibility of novel point-of-care diagnostics for febrile illnesses at health centres in Southeast Asia: a mixed-methods study by Adella, FJ, Vanna, M, Adhikari, B, Ol, S, Tripura, R, Davoeung, C, Callery, JJ, Sovann, Y, Chandna, A, Bunreth, V, Asnong, C, von Seidlein, L, Dondorp, AM, Maude, RJ, Lubell, Y, Wills, B, Lek, D, Peto, TJ