Browsing by Author "Koepfli, C."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Author Correction: The temporal dynamics and infectiousness of subpatent Plasmodium falciparum infections in relation to parasite density(Nature communications, 2019-06-11) Koram, K.; Slater, H.C.; Ross, A.; Felger, I.; Hofmann, N.E.; Robinson, L.; Cook, J.; Gonçalves, B.P.; Björkman, A.; Ouedraogo, A.L.; Morris, U.; Msellem, M.; Koepfli, C.; Mueller, I.; Tadesse, F.; Gadisa, E.; Das, S.; Domingo, G.; Kapulu, M.; Midega, J.; Owusu-Agyei, S.; Nabet, C.; Piarroux, R.; Doumbo, O.; Doumbo, S.N.; Koram, K.; Lucchi, N.; Udhayakumar, V.; Mosha, J.; Tiono, A.; Chandramohan, D.; Gosling, R.; Mwingira, F.; Sauerwein, R.; Paul, R.; Riley, E.M.; White, N.J.; Nosten, F.; Imwong, M.; Bousema, T.; Drakeley, C.; Okell, L.C.Item Reactive case detection of Plasmodium falciparum in western Kenya highlands: effective in identifying additional cases, yet limited effect on transmission(Malaria Journal, 2018-03) Aidoo, E.K.; Afrane, Y.A.; Machani, M.G.; Chebore, W.; Lawson, B.W.; Atieli, H.; Kariuki, S.; Lee, M.C.; Koepfli, C.; Zhou, G.; Githeko, A.K.; Yan, G.Background Identifying asymptomatic reservoirs of malaria parasites using index cases as entry points into the community is potentially a cost-effective way towards achieving malaria elimination. Methods Within 1 year, 1430 confirmed malaria cases were identified in Marani hospital, western Kenya. Fifty cases were followed up, and 108 index case household members and 612 neighbours within a 100 m radius were screened. As controls, samples were collected from 510 individuals matched with index cases and located at a distance of ≥ 500 m from them. Infections were diagnosed by microscopy and PCR while simultaneously collecting malaria vectors indoor using pyrethrum spray catches. Results In the index case and neighbour households, the prevalence of infection was approximately twice as high as in control households (by PCR: index cases households: 28.9%, neighbours: 25.3%, matched controls: 12.9%). In index case households, the indoor vector density (Anopheles gambiae and Anopheles funestus) was higher (0.46 female/house/night) than in neighbouring (0.31 f/h/n) and control houses (0.29 f/h/n). Conclusions Screening index case households and neighbours approximately doubles the chance to detect asymptomatic infections compared to randomly selected households. However, even if all cases were followed up, only a small proportion (˂ 10%) of the asymptomatic reservoir in the population would have been identified. Control programmes need to weigh the increased chance to find cases around index cases vs. the logistical challenges to target this subgroup within the population.Item The temporal dynamics and infectiousness of subpatent Plasmodium falciparum infections in relation to parasite density(Nature Communications, 2019) Slater, H.C.; Ross, A.; Felge, I.; Hofmann, N.E.; Robinson, L.; Cook, J.; Gonçalves, B.P.; Björkman, A.; Ouedraogo, A.L.; Morris, U.; Msellem, M.; Koepfli, C.; Mueller, I.; Tadesse, F.; Gadisa, E.; Das, S.; Domingo, G.; Kapulu, M.; Midega, J.; Owusu-Agyei, S.; Nabet, C.; Piarroux, R.; Doumbo, O.; Doumbo, S.N.; Koram, K.; Lucchi, N.; Udhayakumar, V.; Mosha, J.; Tiono, A.; Chandramohan, D.; Gosling, R.; Mwingira, F.; Sauerwein, R.; Riley, E.M.; White, N.J.; Nosten, F.; Imwong, M.; Bousema, T.; Drakeley, C.; Okell, L.C.Malaria infections occurring below the limit of detection of standard diagnostics are common in all endemic settings. However, key questions remain surrounding their contribution to sustaining transmission and whether they need to be detected and targeted to achieve malaria elimination. In this study we analyse a range of malaria datasets to quantify the density, detectability, course of infection and infectiousness of subpatent infections. Asymptomatically infected individuals have lower parasite densities on average in low transmission settings compared to individuals in higher transmission settings. In cohort studies, subpatent infections are found to be predictive of future periods of patent infection and in membrane feeding studies, individuals infected with subpatent asexual parasite densities are found to be approximately a third as infectious to mosquitoes as individuals with patent (asexual parasite) infection. These results indicate that subpatent infections contribute to the infectious reservoir, may be long lasting, and require more sensitive diagnostics to detect them in lower transmission settings. © 2019, The Author(s).