TY - JOUR
T1 - Reactive case detection of Plasmodium falciparum in western Kenya highlands
T2 - Effective in identifying additional cases, yet limited effect on transmission
AU - Aidoo, Ebenezer K.
AU - Afrane, Yaw A.
AU - Machani, Maxwell Gesuge
AU - Chebore, Winnie
AU - Lawson, Bernard Walter
AU - Atieli, Harrysone
AU - Kariuki, Simon
AU - Lee, Ming Chieh
AU - Koepfli, Cristian
AU - Zhou, Guofa
AU - Githeko, Andrew K.
AU - Yan, Guiyun
N1 - Publisher Copyright:
© 2018 The Author(s).
PY - 2018/3/13
Y1 - 2018/3/13
N2 - 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 (Ë' 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.
AB - 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 (Ë' 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.
KW - Asymptomatic parasite carriers
KW - Index case
KW - Neighbourhood
KW - Reactive case detection
UR - http://www.scopus.com/inward/record.url?scp=85043580909&partnerID=8YFLogxK
U2 - 10.1186/s12936-018-2260-2
DO - 10.1186/s12936-018-2260-2
M3 - Article
C2 - 29534709
AN - SCOPUS:85043580909
SN - 1475-2875
VL - 17
JO - Malaria Journal
JF - Malaria Journal
IS - 1
M1 - 111
ER -