Most people have heard of ‘river blindness’ and seen the devastating, memorable images of people suffering from the disease. Also known as onchocerciasis, the disease is transmitted by blackflies (Simulium spp.) that breed in fast-flowing rivers. When an infective blackfly bites a person, a nematode worm (Onchocerca volvulus) enters the person’s body, and nine months later may become an adult worm. Mated adult female worms release offspring known as microfilariae at a rate of 1,600 per day. These microscopic worms invade the person’s skin, eyes and other organs, causing intense irritation, sight loss and even blindness.
Rodents, especially rats and mice, have been a known public health threat for centuries and are emblematic of poverty, underdevelopment and epidemics. They attack and damage crops grown in the field, as well as damaging stored crops in homes, warehouses and factories, effectively damaging and contaminating food across all production value chains. Rodents cause problems in cities, where they feed on human refuse, damage sewage and drainage systems, undermine foundations, damage electrical wires and gas supplies and can terrorise citizens by entering people’s homes and even biting people. There have been increasing case numbers of serious diseases linked to rats, including plague, Lassa fever, hantavirus, leptospirosis, typhus, toxoplasmosis, babesiosis, Lyme disease and leishmaniasis. With rodents transmitting more than 60 diseases to people and domestic animals, damaging food production systems, and exacerbating sanitation problems, few would argue society’s rodent problems have been solved.
Malaria affects over 200 million people every year, mostly in sub-Saharan Africa. The 2018 WHO World Malaria Report showed that in 2017, almost half of the world’s population were at risk of malaria and nearly half a million people died from the disease, the majority of deaths being in children under the age of five. The malaria parasite is spread through the bites of infected female mosquitoes, mostly of the species Anopheles gambiae, as they take their blood meals. Malaria is preventable and curable. However, whilst campaigns based on indoor spraying and the distribution of bed nets have made great progress, these approaches are reaching the limits of their efficacy, and even in areas where nets are distributed free, the use of nets is not universal, nor are they always in good repair.
Certain insect pests, including aphids, beetles, flies, locusts, mites, moths, true bugs, are so destructive that they cause billions of pounds’ worth of damage to the agricultural and horticultural sectors and to other industries, across the UK and worldwide.