Until 1942, Allied medics had distributed a daily dosage of five grains of quinine to all army personnel, but when supplies ran low, they experimented with synthesised versions of the drug. They tested two prototypes: quinacrine (reverse-engineered by Sterling Winthrop Co. from a captured German I. G. Farben product in 1941) and mepacrine (synthesised by Imperial Chemical Industries in 1939). British Army experiments showed that quinacrine was a superior antimalarial because it had few side effects, but mepacrine was in greater supply, so the Allied doctors in Accra settled on a daily dose of the latter by mid-1943. The White soldiers disliked mepacrine because it caused a yellowish pigmentation on their skin, but they were forced to take it every morning with their breakfast. African soldiers were required to take the drug too, but use of chemical prophylaxes stopped there. Despite the belief that the residents of Accra formed a reservoir for the disease, the Allies never considered offering malaria prophylaxes to their civilian employees or to the broader African community.

At the start of the campaign, the Allies hoped that chemical insecticides might help them avoid the expense of reengineering the Korle watershed. The Americans were especially interested in using a silver-bullet approach to control the local mosquito population because they did not want to fund infrastructure projects that they would have to abandon after the war. In April 1942, the US Army began spraying the larvicide Paris green on open water surrounding the barracks, and trucked pyrethrum aerosol bombs into British camps to clear the buildings of mosquitoes. They proceeded to spray all houses within a one-mile radius of the airport, three times a week. In 1944, when adequate supplies became available, they switched to spraying with dichlorodiphenyltrichloroethane (DDT), and by the end of the year, they were spraying all villages within an eight-mile radius of their camps, including the Accra city centre. Because DDT was not considered toxic to humans, the Malaria Control Group believed it was safe to disperse the chemical into water supplies. By 1944, the Allies commissioned a Piper J-3 cub to aerial spray the Korle, Kpeshi, and Klotey Lagoons, as well as partially spraying at the Sakumo Lagoon, several kilometres to the west of the city.

The spraying campaigns of 1942–45 were conducted at great expense in labour and materiel. For instance, during a three-month surge to eliminate the presence of mosquitoes and mosquito larvae at the airport in 1944, the Americans sprayed more than 1,000 pounds of Paris green, 2,000 pounds of pyrethrum, and 500 pounds of DDT, and they still found larvae in some of the streams leading into the lagoon. Major Macdonald had always believed that it would be cost effective to take the time to build drainage systems that would confine water to ditches and ponds, where smaller amounts of insecticides could be used, and as the war dragged on, the Americans too began to see the necessity of longer-term planning. In 1944, Allied engineers mapped out a pesticide spraying zone, re-dredged the sea outfall, and employed African crew to clear ditches and streams all the way up the Korle watershed. The Royal Army Medical Services followed up by spraying and oiling the waterways on a regular basis, a method that reduced the amount of pesticides used.

While the drainage scheme proceeded, Lt. Ribbands built his aforementioned Malaria Field Laboratory and began by collecting data about mosquito populations in the army camps. An expert on Anopheles gambiae, Lt. Ribbands had already researched the flight and biting habits of mosquitoes through a variety of experiments in India and West Africa, and his first step was to replicate a study that he had conducted in Sierra Leone, collecting mosquitoes from the Gold Coast Regiment barracks. The mosquito crew spread sheets on the floors of the tents and sprayed the air with pyrethrum or DDT to kill any insects inside. Afterward, Lt. Ribbands hired local men to pick up the mosquitoes and take them to a central laboratory at the airport for identification.

Lt. Ribbands and the malariologists expected to eliminate the mosquitoes around the Allied army barracks, but when he analysed the early results, he realised that the health of soldiers was still compromised by the in-flight of mosquitoes from nearby villages. According to the Allied records, the fear of contagion spurred the Malaria Control Group to relocate the villagers outside the airport to a newly conceived one-mile sanitary cordon. If this is true, then the Allies had extended the supposed flight range of a mosquito from one-quarter of a mile to a full mile and relocated the people of nearby Nima and Kanda because they had become “reservoirs of disease.” But though there are brief references to the planned evacuation of these nearby villages, no particular records demonstrate that a forced removal took place. If the evacuations did occur, they would have entailed the movement of hundreds of people (mostly Muslim newcomers to the city) by truck, as well as extensive documentation of claims for property. The lack of a paper trail raises the question of whether the residents of the villages were in fact relocated, but whether they were moved or not, a new spatial reckoning of Accra had been created because of the threat posed by infected mosquitoes.

Once he had established a cordon around the periphery of Korle Lagoon, Lt. Ribbands began to track the movements of Anopheles gambiae using his network of mosquito sheds. Built by African labourers in the employ of the British Army, the traps were single-room, timber-frame structures covered with screens and tar paper and fitted with baffles to let mosquitoes in at night. Ribbands modelled his traps on a prototype developed by American entomologist E. H. Magoon, but with a substantial difference: during his research in Jamaica, Magoon used only horses and mules to attract mosquitoes. Lt. Ribbands preferred human bait. Since he was largely concerned with studying the attraction of mosquitoes to White soldiers, it would have been logical to assign an American or British soldier to live in the traps, but the Allies were shorthanded, and Lt. Ribbands did not want to risk Allied airmen catching malaria. As a compromise, he hired African workers to sleep in the traps: “Africans selected as bait were chiefly men from the Northern Territories of the Gold Coast. They were chosen because most of them were homeless and it was felt that they would welcome the fine shelters provided by the mosquito traps, however, only those who could speak a few words of English were hired because they had to be able to understand the simple instructions. That the traps were home to these men was soon obvious when it was seen that they preferred to remain in the vicinity even during the daytime when they were not working.”

The choice of migrant workers as human bait is not surprising. These men go unnamed in the military records, but they were likely drawn from the same pool of immigrants recruited by the Gold Coast Medical Department as so-called volunteers in experiments at the Accra Laboratory during outbreaks of yellow fever and relapsing fever. But if they were homeless, as Ribbands suggested, it probably did not mean that they had nowhere to sleep. Newcomers to Accra usually were able to find a bed, even if that meant crowding in with their fellow migrants. And even if they did lack permanent residences, it is difficult to believe that they considered the traps desirable places to sleep. The sheds were small, filled with bugs, and lacking the benefit of the slightest breeze to cool the skin. It is also implausible that they thought of the traps as homes, considering that they were located in wooded areas and did not have locks to secure the doors. Moreover, the sheds were spread around a perimeter of several kilometres, and Lt. Ribbands rotated the men through the network of sheds at weekly intervals.

The military records also show that the hired bait did not always follow the rules. The men were required to stay in their sheds from sunset to sunrise. When they awoke, they were to leave the traps, carefully closing the baffles to catch the mosquitoes inside as they left, so that the spraying crew could lay down a tarpaulin, spray the sheds, and collect the insects. To monitor the sleeping patterns, Lt. Ribbands sent soldiers around the perimeter to ensure that the men serving as bait were actually sleeping in the traps and to prevent a reported “tendency to sit outside the trap at night”— an indication that the Africans who took part in the Malaria Control Group studies were not always willing and forthright participants. Though there is no record of outright resistance, the migrants did take measures to avoid mosquito bites and preserve their dignity.

[This piece is culled from a bookauthored by Jonathan Roberts, titled:Sharing the burden of sickness: A historyof healing and medicine in Accra]