In a contest to establish which organism causes the greatest sum of human suffering, the mosquito would undoubtedly finish pretty high up. More than a million people die every year from diseases spread by mosquitoes, almost all of them in the developing world; malaria heads the mortality list, followed by dengue fever, chikungunya, yellow fever, West Nile virus and Japanese encephalitis. Other insects are almost as harmful: the tsetse fly spreads sleeping sickness; sand flies pass on leishmaniasis; household (or “kissing”) bugs spread Chagas disease; fleas transmit plague; and black flies spread river blindness.

But this toll is starting to decline, as new funding increases the pace of treatment and research. Having been neglected during the late-20th century, the battle against insect-borne diseases is now attracting hundreds of millions of dollars in funding from governments, charities and the private sector. As the biggest killer, malaria receives the largest share of this.