Seasonality in pulmonary tuberculosis among migrant workers entering Kuwait

<p>Abstract</p> <p>Background</p> <p>There is paucity of data on seasonal variation in pulmonary tuberculosis (TB) in developing countries contrary to recognized seasonality in the TB notification in western societies. This study examined the seasonal pattern in TB diagnosis among migrant workers from developing countries entering Kuwait.</p> <p>Methods</p> <p>Monthly aggregates of TB diagnosis results for consecutive migrants tested between January I, 1997 and December 31, 2006 were analyzed. We assessed the amplitude (<it>α</it>) of the sinusoidal oscillation and the time at which maximum (<it>θ</it>°) TB cases were detected using Edwards' test. The adequacy of the hypothesized sinusoidal curve was assessed by <it>χ</it>²goodness-of-fit test.</p> <p>Results</p> <p>During the 10 year study period, the proportion (per 100,000) of pulmonary TB cases among the migrants was 198 (4608/2328582), (95% confidence interval: 192 – 204). The adjusted mean monthly number of pulmonary TB cases was 384. Based on the observed seasonal pattern in the data, the maximum number of TB cases was expected during the last week of April (<it>θ</it>° = 112°; <it>P </it>< 0.001). The amplitude (± se) (<it>α </it>= 0.204 ± 0.04) of simple harmonic curve showed 20.4% difference from the mean to maximum TB cases. The peak to low ratio of adjusted number of TB cases was 1.51 (95% CI: 1.39 – 1.65). The <it>χ</it>²goodness-of-test revealed that there was no significant (<it>P </it>> 0.1) departure of observed frequencies from the fitted simple harmonic curve. Seasonal component explained 55% of the total variation in the proportions of TB cases (100,000) among the migrants.</p> <p>Conclusion</p> <p>This regularity of peak seasonality in TB case detection may prove useful to institute measures that warrant a better attendance of migrants. Public health authorities may consider re-allocation of resources in the period of peak seasonality to minimize the risk of <it>Mycobacterium tuberculosis </it>infection to close contacts in this and comparable settings in the region having similar influx of immigrants from high TB burden countries. Epidemiological surveillance for the TB risk in the migrants in subsequent years and required chemotherapy of detected cases may contribute in global efforts to control this public health menace.</p

Evidence of maternal QTL affecting growth and obesity in adult mice

Most quantitative trait loci (QTL) studies fail to account for the effect that the maternal genotype may have on an individual’s phenotypes, even though maternal effect QTL have been shown to account for considerable variation in growth and obesity traits in mouse models. Moreover, the fetal programming theory suggests that maternal effects influence an offspring’s adult fitness, although the genetic nature of fetal programming remains unclear. Within this context, our study focused on mapping genomic regions associated with maternal effect QTL by analyzing the phenotypes of chromosomes 2 and 7 subcongenic mice from genetically distinct dams. We analyzed 12 chromosome 2 subcongenic strains that spanned from 70 to 180 Mb with CAST/EiJ donor regions on the background of C57BL/6 J, and 14 chromosome 7 subcongenic strains that spanned from 81 to 111 Mb with BALB/cByJ donor regions on C57BL/6ByJ background. Maternal QTL analyses were performed on the basis of overlapping donor regions between subcongenic strains. We identified several highly significant (P < 5 × 10−4) maternal QTL influencing total body weight, organ weight, and fat pad weights in both sets of subcongenics. These QTL accounted for 1.9-11.7% of the phenotypic variance for growth and obesity and greatly narrowed the genomic regions associated with the maternal genetic effects. These maternal effect QTL controlled phenotypic traits in adult mice, suggesting that maternal influences at early stages of development may permanently affect offspring performance. Identification of maternal effects in our survey of two sets of subcongenic strains, representing approximately 5% of the mouse genome, supports the hypothesis that maternal effects represent significant sources of genetic variation that are largely ignored in genetic studies

Why Rice Farmers Don't Sail: Coastal Subsistence Traditions and Maritime Trends in Early China

The Lower Yangtze River Valley is a key region for the early development of rice farming and the emergence of wet rice paddy field systems. Subsistence evidence from Neolithic sites in this area highlights the importance of freshwater wetlands for both plant and animal food resources. Early Neolithic rice cultivators looked inland, especially to wetlands and nearby woodlands, for their main protein sources. Links to the sea among these Neolithic populations are notably scarce. Due to the high yields of wet rice, compared with other staple crops as well as dryland rice, the wetland rice focused subsistence strategy of the Lower Yangtze would have supported high, and increasing, local population densities. Paddy agriculture demands labor input and water management on a large scale, which would have stimulated and reinforced trends towards more complex societies, such as that represented by Liangzhu in the lower Yangtze region. Population growth could have been largely absorbed locally, suggesting that population packing, not migration, was the dominant trend. Other case studies of agricultural dispersal, for the Korean Peninsula and Japan further illustrate the lack of correlation between the spread of rice agriculture and wet rice cultivation. Although wet rice cultivation was a pull factor that drew local populations towards increased density and increased social complexity, it did not apparently push groups to migrate outwards. Instead, the transition from wetland to rain fed rice cultivation systems and/or the integration of rice with rain fed millet crops are much more likely to have driven the demographic dynamics that underpin early farmer migrations and crop dispersal

Novel facultative Methylocella strains are active methane consumers at terrestrial natural gas seeps

Natural gas seeps contribute to global climate change by releasing substantial amounts of the potent greenhouse gas methane and other climate-active gases including ethane and propane to the atmosphere. However, methanotrophs, bacteria capable of utilising methane as the sole source of carbon and energy, play a significant role in reducing the emissions of methane from many environments. Methylocella-like facultative methanotrophs are a unique group of bacteria that grow on other components of natural gas (i.e. ethane and propane) in addition to methane but a little is known about the distribution and activity of Methylocella in the environment. The purposes of this study were to identify bacteria involved in cycling methane emitted from natural gas seeps and, most importantly, to investigate if Methylocella-like facultative methanotrophs were active utilisers of natural gas at seep sites

The Beaker phenomenon and the genomic transformation of northwest Europe

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries