Efficacy of long-lasting insecticidal nets in use in Macha, Zambia, against the local Anopheles arabiensis population

<p>Abstract</p> <p>Background</p> <p>The mosquito <it>Anopheles arabiensis </it>is the primary vector of <it>Plasmodium falciparum </it>in Macha, Zambia. A major portion of Zambia's current malaria control programme relies on long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) with insecticides. Currently, the efficacy of these measures against <it>An. arabiensis </it>in Macha is unknown, and previous data has shown that <it>An. arabiensis </it>has continued to feed on human hosts, despite high ITN coverage. It is possible that this could be due to either decreased efficacy of ITNs in used in Macha, or pyrethroid resistance in the vector.</p> <p>Methods</p> <p>F1 offspring of field-collected adult <it>An. arabiensis </it>were tested for insecticide resistance, using CDC bottle bioassays and deltamethrin ITN susceptibility assays. The mosquitoes were characterized for the knock-down resistance (<it>kdr</it>) allele by PCR. LLINs that had been in use for two years in nearby villages were collected and tested for residual deltamethrin concentration and net quality, and were used in bioassays against susceptible colonized <it>Anopheles gambiae </it>s.s. Keele. Additionally, a survey on ITN use and care was conducted among LLIN owners.</p> <p>Results</p> <p>In the F1 <it>An</it>. arabiensis field population, low levels of resistance to DDT and deltamethrin-treated net material were detected by bioassay, although the knock-down resistance (<it>kdr</it>) allele not present in the population. ITN evaluations revealed high variability in residual deltamethrin concentration, quality of the nets, and mosquito mortality in bioassays. Mortality against <it>An. gambiae </it>s.s. in bioassays was correlated with residual deltamethrin concentration, which was dependent upon the number of washes each net had received.</p> <p>Conclusions</p> <p>Proper LLIN care was a strong determinant of LLIN efficacy, indicating that education on the importance of LLIN use and care is key when distributing nets. As there is little insecticide resistance in the local vector population, degradation of LLINs most likely allowed for continued human feeding by <it>An. arabiensis</it>. Continued monitoring and assessment of both the vector population and the efficacy of LLINs in use is necessary in order to appropriately modify vector control operations and prevent the development of pyrethroid resistance.</p

A New Paradigm for International Business Transactions

This Article offers a theoretical analysis of international business law

Health professionals' perceptions of cultural influences on stroke experiences and rehabilitation in Kuwait

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Informa UK Ltd.Purpose: The aim of this study was to investigate the perceptions of health professionals who treat stroke patients in Kuwait regarding cultural influences on the experience of stroke and rehabilitation in Kuwait. Health professionals interviewed were from a variety of cultural backgrounds thus providing an opportunity to investigate how they perceived the influence of culture on stroke recovery and rehabilitation in Kuwait. Method: Semi-structured interviews were carried out with 12 health professionals with current/recent stroke rehabilitation experience in Kuwait, followed by thematic analysis of the verbatim transcripts. Results: The health professionals identified several features of the Kuwaiti culture that they believed affected the experiences of stroke patients. These were religious beliefs, family involvement, limited education and public information about stroke, prevailing negative attitudes toward stroke, access to finances for private treatment, social stigma and the public invisibility of disabled people, difficulties identifying meaningful goals for rehabilitation, and an acceptance of dependency linked with the widespread presence of maids and other paid assistants in most Kuwaiti homes. Conclusion: To offer culturally sensitive care, these issues should be taken into account during the rehabilitation of Kuwaiti stroke patients in their home country and elsewhere

Detection of Lead in the Carbon-Rich, Very Metal-Poor Star LP625-44: A Strong Constraint on s-Process Nucleosynthesis at Low Metallicity

We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture elements. The abundance pattern between Ba and Pb agrees well with a scaled solar system s-process component, while the lighter elements (Sr-Zr) are less abundant than Ba. The enhancement of s-process elements is interpreted as a result of mass transfer in a binary system from a previous AGB companion, an interpretation strongly supported by radial velocity variations of this system. The detection of Pb makes it possible, for the first time, to compare model predictions of s-process nucleosynthesis in AGB stars with observations of elements between Sr and Pb. The Pb abundance is significantly lower than the prediction of recent models (e.g., Gallino et al. 1998), which succeeded in explaining the metallicity dependence of the abundance ratios of light s-elements (Sr-Zr) to heavy ones (Ba-Dy) found in previously observed s-process-enhanced stars. This suggests that one should either (a) reconsider the underlying assumptions concerning the 13C-rich s-processing site (13C-pocket) in the present models, or (b) investigate alternative sites of s-process nucleosynthesis in very metal-poor AGB stars.Comment: 10 pages, 3 figures, Astrophysical Journal Letters, in pres