Computing the Geographic Extent of Maternity Health Services to Predict the Utilization of Skilled Delivery in Siaya County, Western Kenya

In Kenya, no study has attempted to incorporate the target population, nor the availability coverage and accessibility coverage to expose hidden gaps in the provision of maternity health services that target rural and marginalized populations for a high burden, yet low resource setting such as rural Siaya County. A cross-sectional study design used publicly available geospatial data in combination with administrative ward level data from the web-based district health information software, version 2 (DHIS 2). AccessMod version 5 was used for geographic coverage analysis. ArcGIS (version 10.5) and R (version 3.5.3)sufficed for the preparation of input geospatial data and the manipulation of AccessMod results respectively. The association between the geographic coverage and skilled delivery was computed using a Zero-inflated Poisson regression model at a 95% confidence level. The findings in Siaya County revealed a higher likelihood of a skilled delivery 34% (0.34; CI: 0.339–0.347) and 16% (0.16; CI: 0.162–0.167) respectively. This likelihood is for every unit increase in the proportion of pregnant women within a one-hour geographic extent of a hospital and health center—on foot, as compared to being within a similar geographic catchment area of a dispensary 7% (0.07; CI: 0.0678–0.0723) based on motorcycle traveling time. The immediate implication is that the population coverage capacity and, by extension, quality of existing facilities offering free maternity health services increases a pregnant woman’s likelihood of utilizing skilled delivery, regardless of proximity. Future research should also consider looking at the cost-implications of scaling up existing maternity health services, albeit based on local routine health facility data

Prevalence of Under Nutrition and Its Effects on Response to Malaria Treatments Among Children Under Five Years at Ahero and Homa Bay Hospitals, Western Kenya

Nutritional status of a person with malaria infection is thought to contribute to host treatment outcome. Limited studies have investigated the association despite the widespread concern with nutrition in malaria endemic areas. We evaluated the impact of under nutrition on the treatment outcome by Artemether Lumefantrine and Clindamycin plus Quinine. Sample of 384 children aged below five years diagnosed with uncomplicated Plasmodium falciparum malaria, were randomized to receive Clindamycin plus quinine or Artemether-lumefantrine (AL) for treatment. The children were followed up for 28 days to monitor body weight and height, clinical and parasitological parameters of treatment response.Outcomes included parasite clearance at days 2 and 3 and risk of recurrent parasitemia after 28 days of follow-up. Prevalence of underweight was 6 % (n=23) and stunting was 12% (n=45). Body weight increased over the 28 day follow up period. The initial mean weight was 13.03kg while the mean weight on day 28 was 13.7kg.The proportion of children with stunting was comparable between the female and male children: 40% verse 60%, p=0.06. Generally, the prevalence of underweight was comparable between the treatment arms (p=0.08). Similarly, the prevalence of stunting was not significantly different between the treatment arms (p=0.34). Cure rate was high in the Artemether group (96.5%) compared to the Clindamycin group (44.2%). Children who were underweight were 0.69 times less likely to be cured compared to those who were not underweight, but this difference was not significantly different from that of children were had no underweight (p = 0.429). Treatment outcomes were known for 43 of the 45 (95.6%) children with stunting. Overall, stunted children were 1.15 times more likely to be cured compared with children who were not stunted, but this difference was not statistically significant (p=0.704). No association between under nutrition (underweight and stunting) and treatment outcome was observed.  Further research is suggested on the impact of under nutrition on response to malaria treatment using Artemether Lumefantrine alone on children less than five years. Ministry of health and other policy makers may formulate guidelines to improve management of children with malaria taking into consideration their nutritional status, and to integrate nutrition in malaria programmes

The Impact of Divergence Time on the Nature of Population Structure: An Example from Iceland

The Icelandic population has been sampled in many disease association studies, providing a strong motivation to understand the structure of this population and its ramifications for disease gene mapping. Previous work using 40 microsatellites showed that the Icelandic population is relatively homogeneous, but exhibits subtle population structure that can bias disease association statistics. Here, we show that regional geographic ancestries of individuals from Iceland can be distinguished using 292,289 autosomal single-nucleotide polymorphisms (SNPs). We further show that subpopulation differences are due to genetic drift since the settlement of Iceland 1100 years ago, and not to varying contributions from different ancestral populations. A consequence of the recent origin of Icelandic population structure is that allele frequency differences follow a null distribution devoid of outliers, so that the risk of false positive associations due to stratification is minimal. Our results highlight an important distinction between population differences attributable to recent drift and those arising from more ancient divergence, which has implications both for association studies and for efforts to detect natural selection using population differentiation

Pitfalls of predicting complex traits from SNPs

The success of genome-wide association studies (GWASs) has led to increasing interest in making predictions of complex trait phenotypes, including disease, from genotype data. Rigorous assessment of the value of predictors is crucial before implementation. Here we discuss some of the limitations and pitfalls of prediction analysis and show how naive implementations can lead to severe bias and misinterpretation of results

Population Genetics of GYPB and Association Study between GYPB*S/s Polymorphism and Susceptibility to P. falciparum Infection in the Brazilian Amazon

Merozoites of Plasmodium falciparum invade through several pathways using different RBC receptors. Field isolates appear to use a greater variability of these receptors than laboratory isolates. Brazilian field isolates were shown to mostly utilize glycophorin A-independent invasion pathways via glycophorin B (GPB) and/or other receptors. The Brazilian population exhibits extensive polymorphism in blood group antigens, however, no studies have been done to relate the prevalence of the antigens that function as receptors for P. falciparum and the ability of the parasite to invade. Our study aimed to establish whether variation in the GYPB*S/s alleles influences susceptibility to infection with P. falciparum in the admixed population of Brazil.Two groups of Brazilian Amazonians from Porto Velho were studied: P. falciparum infected individuals (cases); and uninfected individuals who were born and/or have lived in the same endemic region for over ten years, were exposed to infection but have not had malaria over the study period (controls). The GPB Ss phenotype and GYPB*S/s alleles were determined by standard methods. Sixty two Ancestry Informative Markers were genotyped on each individual to estimate admixture and control its potential effect on the association between frequency of GYPB*S and malaria infection.GYPB*S is associated with host susceptibility to infection with P. falciparum; GYPB*S/GYPB*S and GYPB*S/GYPB*s were significantly more prevalent in the in the P. falciparum infected individuals than in the controls (69.87% vs. 49.75%; P<0.02). Moreover, population genetics tests applied on the GYPB exon sequencing data suggest that natural selection shaped the observed pattern of nucleotide diversity.Epidemiological and evolutionary approaches suggest an important role for the GPB receptor in RBC invasion by P. falciparum in Brazilian Amazons. Moreover, an increased susceptibility to infection by this parasite is associated with the GPB S+ variant in this population

Forward-time simulation of realistic samples for genome-wide association studies

<p>Abstract</p> <p>Background</p> <p>Forward-time simulations have unique advantages in power and flexibility for the simulation of genetic samples of complex human diseases because they can closely mimic the evolution of human populations carrying these diseases. However, a number of methodological and computational constraints have prevented the power of this simulation method from being fully explored in existing forward-time simulation methods.</p> <p>Results</p> <p>Using a general-purpose forward-time population genetics simulation environment, we developed a forward-time simulation method that can be used to simulate realistic samples for genome-wide association studies. We examined the properties of this simulation method by comparing simulated samples with real data and demonstrated its wide applicability using four examples, including a simulation of case-control samples with a disease caused by multiple interacting genetic and environmental factors, a simulation of trio families affected by a disease-predisposing allele that had been subjected to either slow or rapid selective sweep, and a simulation of a structured population resulting from recent population admixture.</p> <p>Conclusions</p> <p>Our algorithm simulates populations that closely resemble the complex structure of the human genome, while allows the introduction of signals of natural selection. Because of its flexibility to generate different types of samples with arbitrary disease or quantitative trait models, this simulation method can simulate realistic samples to evaluate the performance of a wide variety of statistical gene mapping methods for genome-wide association studies.</p

Worldwide population differentiation at disease-associated SNPs

<p>Abstract</p> <p>Background</p> <p>Recent genome-wide association (GWA) studies have provided compelling evidence of association between genetic variants and common complex diseases. These studies have made use of cases and controls almost exclusively from populations of European ancestry and little is known about the frequency of risk alleles in other populations. The present study addresses the transferability of disease associations across human populations by examining levels of population differentiation at disease-associated single nucleotide polymorphisms (SNPs).</p> <p>Methods</p> <p>We genotyped ~1000 individuals from 53 populations worldwide at 25 SNPs which show robust association with 6 complex human diseases (Crohn's disease, type 1 diabetes, type 2 diabetes, rheumatoid arthritis, coronary artery disease and obesity). Allele frequency differences between populations for these SNPs were measured using Fst. The Fst values for the disease-associated SNPs were compared to Fst values from 2750 random SNPs typed in the same set of individuals.</p> <p>Results</p> <p>On average, disease SNPs are not significantly more differentiated between populations than random SNPs in the genome. Risk allele frequencies, however, do show substantial variation across human populations and may contribute to differences in disease prevalence between populations. We demonstrate that, in some cases, risk allele frequency differences are unusually high compared to random SNPs and may be due to the action of local (i.e. geographically-restricted) positive natural selection. Moreover, some risk alleles were absent or fixed in a population, which implies that risk alleles identified in one population do not necessarily account for disease prevalence in all human populations.</p> <p>Conclusion</p> <p>Although differences in risk allele frequencies between human populations are not unusually large and are thus likely not due to positive local selection, there is substantial variation in risk allele frequencies between populations which may account for differences in disease prevalence between human populations.</p

Hand hygiene practice among healthcare workers at the surgical orthopedic wards of Jaramogi Oginga Odinga Teaching And Referral Hospital, Kenya

Background: Hand hygiene practice is the most-simple and cost-effective way to prevent Hospital Acquired Infections. However, limited audit exists on the adherence to hand hygiene practice by healthcare workers in surgical orthopedic wards of a referral hospital in Western Kenya. Objective: evaluate adherence level to hand hygiene practice in the surgical orthopedic wards at a referral hospital. Design: descriptive cross-sectional survey. Setting: Surgical orthopedic wards in Jaramogi Oginga Odinga Teaching and Referral Hospital. Subjects: 31 healthcare workers employed at the hospital. Results: Among 7 doctors and 24 nurses, 39% agreed there was constant running water in the wards, 45.2% agreed there was constant supply of hand wash soap and 16% agreed there was evaluation and provision of feedback of hand hygiene practice. Only 12.9% agreed on the availability of hand sanitizer in and out of the rooms. Twenty six percent and 13% reported stock out of sanitizers and occasional dry taps respectively. However, 22.6 % agreed of washing hands before and after attending to a patient. Notably, 61% reported taking care of many patients as a barrier to hand hygiene practice. Doctors and nurses take care of twice and thrice respectively as many patients as recommended by World Health Organization. Water for hand wash was more available than hand sanitizer (P=0.006). Conclusion: Several challenges for effective adherence to hand hygiene practice exist and more emphasis needs to be put on staffing, strengthening infection control manuals and exploring a complementary use of soaps and sanitizers for sustainability in poor resource settings

Impact of land use on the distribution and diversity of entomopathogenic nematodes in embu and taita districts, kenya

Natural entomopathogenic nematodes (EPNs) are considered as potential biological control agents against soil-borne insect pests. This study was conducted to determine the impact of land use on the distribution, occurrence and diversity of entomopathogenic nematode community. Isolation of EPNs was done using the baiting technique and application of morphological identification methods revealed presence of the genus Steinernema. Land use intensification negatively affected the occurrence and recovery frequency in soils of Embu and Taita districts. The occurrence of EPNs was high in soils from coffee than maize and beans which had more nematodes than planted forest and napier grass followed by natural forest and tea respectively. PCR-RFLP of the internal transcribed spacer region on the ribosomal(r) DNA of the EPN isolates and digestion of the products by Alu I enzyme showed molecular variations among the isolates. The study has demonstrated that the frequency of occurrence and species variation of EPNs is different in various land uses

Elastic scattering of ⁴He atoms at the surface of liquid helium

743-748Elastic scattering of 4He atoms when they approach the surface of 4He liquid, has been studied. The liquid surface is assumed to be uniform and the density profile is the same along and perpendicular to the surface. The incident 4He atom will interact with a large number of 4He atoms in the liquid near the surface of liquid 4He. Hence, the effective interaction of the incident particle will be due to many-body forces. The many-body forces are represented by the t-matrix. In the equation for potential energy per atom in the bulk liquid, the pair potential was replaced by the t-matrix. The Gaussian potential used in calculating the expectation value of the t-matrix is equivalent to the Lennard-Jonnes potential. The results give quantitative agreement with the corresponding experimental values for 4He for the various values of c2. The potential energy per atom in the bulk liquid obtained in this calculation is -20.130 K. The experimental energy of interaction is -20.81K, which implies that the formula derived by us for the potential energy per atom in the bulk liquid works wel