The use of schools for malaria surveillance and programme evaluation in Africa

Effective malaria control requires information on both the geographical distribution of malaria risk and the effectiveness of malaria interventions. The current standard for estimating malaria infection and impact indicators are household cluster surveys, but their complexity and expense preclude frequent and decentralized monitoring. This paper reviews the historical experience and current rationale for the use of schools and school children as a complementary, inexpensive framework for planning, monitoring and evaluating malaria control in Africa. Consideration is given to (i) the selection of schools; (ii) diagnosis of infection in schools; (iii) the representativeness of schools as a proxy of the communities they serve; and (iv) the increasing need to evaluate interventions delivered through schools. Finally, areas requiring further investigation are highlighted

Targeting asymptomatic malaria infections: active surveillance in control and elimination.

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Carbonate secondary porosity development in a polyphase paleokarst from Precambrian system: upper Sinian examples, North Tarim basin, northwest China

Carbonate karst is one of the research highlights in the field of carbonate reservoir geology. High porosity zones can develop in carbonate rocks which are modified by the karst. However, the carbonate porosity development and its evolution process in a polyphase paleokarst are rarely reported in the geological record. Here, the paper focuses on this point from the Precambrian Upper Sinian carbonate in the north Tarim basin, northwest China. Five outcrops and two wells reveal that the karstic porosity development of Upper Sinian carbonate was petrography-controlled of microbial dolostone and grain dolostone. The karstic porosities were in relation to three paleokarst phases: (1) eogenetic karst during depositional environment, (2) telogenetic karst at the end of late Sinian, and (3) hydrothermal karst in the early Permian. Eogenetic karst was related to frequent and short sea-level fluctuation, and was characterized by selective dissolution of intragranular dissolution porosity, moldic porosity, bird’s eye porosity, and intergranular dissolution porosity. Telogenetic karst was related to tectonic uplift, and was characteristic of non-selective dissolution of vugs and cavities with karst intensity increasing upward. Hydrothermal karst was related to geothermal events, and was featured by highly solution-enlarged porosities which mainly overprinted earlier telogenetic and eogenetic karst porosities. The suggested paleokarst model, combined with the related karstic porosity evolution process, will perfectly reveal its porosity development