These are a strict neutral solute channel (human aquaporin 9, AQP9) [10], a prototypical secondary active, proton-driven alternating access monocarboxylate transporter (human MCT1; SLC16 family) [11,12], and the malaria parasite’s lactate transporter (PfFNT; microbial formate–nitrite transporter family) [7,13] (Figure 1b). The gene discussed is AQP9; the disease is malaria.