Comparison of infant malaria incidence in districts of Maputo province, Mozambique

<p>Abstract</p> <p>Background</p> <p>Malaria is one of the principal health problems in Mozambique, representing 48% of total external consultations and 63% of paediatric hospital admissions in rural and general hospitals with 26.7% of total mortality. <it>Plasmodium falciparum </it>is responsible for 90% of all infections being also the species associated with most severe cases. The aim of this study was to identify zones of high malaria risk, showing their spatially and temporal pattern.</p> <p>Methods</p> <p>Space and time Poison model for the analysis of malaria data is proposed. This model allows for the inclusion of environmental factors: rainfall, temperature and humidity as predictor variables. Modelling and inference use the fully Bayesian approach via Markov Chain Monte Carlo (MCMC) simulation techniques. The methodology is applied to analyse paediatric data arising from districts of Maputo province, Mozambique, between 2007 and 2008.</p> <p>Results</p> <p>Malaria incidence risk is greater for children in districts of Manhiça, Matola and Magude. Rainfall and humidity are significant predictors of malaria incidence. The risk increased with rainfall (relative risk - RR: .006761, 95% interval: .001874, .01304), and humidity (RR: .049, 95% interval: .03048, .06531). Malaria incidence was found to be independent of temperature.</p> <p>Conclusions</p> <p>The model revealed a spatial and temporal pattern of malaria incidence. These patterns were found to exhibit a stable malaria transmission in most non-coastal districts. The findings may be useful for malaria control, planning and management.</p

Plastic and Heritable Components of Phenotypic Variation in Nucella lapillus: An Assessment Using Reciprocal Transplant and Common Garden Experiments

Assessment of plastic and heritable components of phenotypic variation is crucial for understanding the evolution of adaptive character traits in heterogeneous environments. We assessed the above in relation to adaptive shell morphology of the rocky intertidal snail Nucella lapillus by reciprocal transplantation of snails between two shores differing in wave action and rearing snails of the same provenance in a common garden. Results were compared with those reported for similar experiments conducted elsewhere. Microsatellite variation indicated limited gene flow between the populations. Intrinsic growth rate was greater in exposed-site than sheltered-site snails, but the reverse was true of absolute growth rate, suggesting heritable compensation for reduced foraging opportunity at the exposed site. Shell morphology of reciprocal transplants partially converged through plasticity toward that of native snails. Shell morphology of F2s in the common garden partially retained characteristics of the P-generation, suggesting genetic control. A maternal effect was revealed by greater resemblance of F1s than F2s to the P-generation. The observed synergistic effects of plastic, maternal and genetic control of shell-shape may be expected to maximise fitness when environmental characteristics become unpredictable through dispersal

Population structure, mortality and growth of Pinna nobilis Linnaeus, 1758 (Mollusca, Bivalvia) at different depths in Moraira bay (Alicante, Western Mediterranean)

An investigation to characterize the causes of Pinna nobilis population structure in Moraira bay (Western Mediterranean) was developed. Individuals of two areas of the same Posidonia meadow, located at different depths (A1, -13 and A2, -6 m), were inventoried, tagged, their positions accurately recorded and monitored from July 1997 to July 2002. On each area, different aspects of population demography were studied (i.e. spatial distribution, size structure, displacement evidences, mortality, growth and shell orientation). A comparison between both groups of individuals was carried out, finding important differences between them. In A1, the individuals were more aggregated and mean and maximum size were higher (A1, 10.3 and A2, 6 individuals/100 m(2); A1, x = 47.2 +/- 9.9; A2, x = 29.8 +/- 7.4 cm, P 0.5, A2, chi(2)= 0.98, df = 2 and 0.3 < P < 0.5). The obtained results have demonstrated that the depth-related size segregation usually shown by P. nobilis is mainly caused by differences in mortality and growth among individuals located at different depths, rather than by the active displacement of individuals previously reported in the literature. Furthermore, dwarf individuals are observed in shallower levels and as a consequence, the relationship between size and age are not comparable even among groups of individuals inhabiting the same meadow at different depths. The final causes of the differences on mortality and growth are also discussed