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1.
Heliyon ; 9(11): e21354, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37954294

ABSTRACT

Biodiesel has several environmental benefits, such as biodegradability, renewability and lower soot emissions. However, biodiesel has undesirable properties such as higher viscosity and density and low calorific value compared to petroleum diesel, resulting in high Brake Specific Fuel Consumption (BSFC), reduced Brake Power (BP) and increased NOX emissions creating an environmental concerns in biodiesel development. This study investigated the effects of synthesizing transesterification catalysts (CaO and NaOH) with Citric Acid (CA) on the quality of biodiesel and biodiesel blends produced from Black Soldier Fly Larvae (BSFL) (Hermetia Illucens). The quality of biodiesel and blends was determined based on fuel properties, engine performance and emission composition characteristics. The tests were performed on a single-cylinder, four-stroke, Compression Ignition (CI) diesel engine at five loads at a constant speed of 1500 rpm. The results showed that synthesizing the catalysts with CA significantly affected the fatty acid profile of the biodiesel compared to physical fuel properties. B100 (pure BSFL biodiesel) exhibited higher BSFC by 10.57-13.97 % and lower BP by 4.21-7.83 % than diesel fuel. However, the Brake Thermal Efficiency (BTE) of biodiesel was higher than that of diesel fuel by 0.82-4.34 % at maximum load. Synthesizing catalysts with CA improved the viscosity of biodiesel by 0.93-2.81 % and effectively reduced NOX, HC and Smoke opacity by 2.23-3.16 %, 4.95-5.83 % and 20.51-41.15 %, respectively.

2.
J Nutr ; 153(4): 970-978, 2023 04.
Article in English | MEDLINE | ID: mdl-36796480

ABSTRACT

BACKGROUND: Early growth and body composition may influence the risk of obesity and health in adulthood. Few studies have examined how undernutrition is associated with body composition in early life. OBJECTIVES: We assessed stunting and wasting as correlates of body composition in young Kenyan children. METHODS: Nested in a randomized controlled nutrition trial, this longitudinal study assessed fat and fat-free mass (FM, FFM) using deuterium dilution technique among children at age 6 and 15 months. This trial was registered at http://controlled-trials.com/ (ISRCTN30012997). Cross-sectional and longitudinal associations between z-score categories of length-for-age (LAZ) or weight-for-length (WLZ) and FM, FFM, fat mass index (FMI), fat-free mass index (FFMI), triceps, and subscapular skinfolds were analyzed by linear mixed models. RESULTS: Among the 499 children enrolled, breastfeeding declined from 99% to 87%, stunting increased from 13% to 32%, and wasting remained at 2% to 3% between 6 and 15 mo. Compared with LAZ >0, stunted children had a 1.12 kg (95% CI: 0.88, 1.36; P < 0.001) lower FFM at 6 mo and increased to 1.59 kg (95% CI: 1.25, 1.94; P < 0.001) at 15 mo, corresponding to differences of 18% and 17%, respectively. When analyzing FFMI, the deficit in FFM tended to be less than proportional to children's height at 6 mo (P ≤ 0.060) but not at 15 mo (P > 0.40). Stunting was associated with 0.28 kg (95% CI: 0.09, 0.47; P = 0.004) lower FM at 6 mo. However, this association was not significant at 15 mo, and stunting was not associated with FMI at any time point. A lower WLZ was generally associated with lower FM, FFM, FMI, and FFMI at 6 and 15 mo. Differences in FFM, but not FM, increased with time, whereas FFMI differences did not change, and FMI differences generally decreased with time. CONCLUSIONS: Overall, low LAZ and WLZ among young Kenyan children were associated with reduced lean tissue, which may have long-term health consequences.


Subject(s)
Adipose Tissue , Body Composition , Female , Humans , Child , Infant , Kenya/epidemiology , Body Mass Index , Longitudinal Studies , Adipose Tissue/metabolism , Cross-Sectional Studies , Cachexia/metabolism , Growth Disorders/epidemiology , Growth Disorders/metabolism
3.
Gynecol Obstet Fertil Senol ; 50(3): 266-271, 2022 Mar.
Article in French | MEDLINE | ID: mdl-34481099

ABSTRACT

Peripartum cardiomyopathy is a rare and unpredictable pregnancy-related pathology. Idiopathic cardiomyopathy is characterized by a heart failure secondary to left ventricular systolic dysfunction appearing towards the end of pregnancy or in the months following delivery with a non-specific clinic presentation. Through reviewing previous research, our critical literature review wishes to bring a concise and objective summarize for a better understanding of physiopathology, evocative symptoms and knowing of factors influencing prognosis in order to standardize peripartum management. The treatment remains mainly symptomatic but other promising treatments are still in development. In conclusion, early detection and treatment allow a better cardiac function recovery reducing cardiac transplantation.


Subject(s)
Cardiomyopathies , Pregnancy Complications, Cardiovascular , Puerperal Disorders , Ventricular Dysfunction, Left , Cardiomyopathies/complications , Cardiomyopathies/diagnosis , Cardiomyopathies/therapy , Female , Humans , Peripartum Period , Pregnancy , Pregnancy Complications, Cardiovascular/diagnosis , Pregnancy Complications, Cardiovascular/therapy , Puerperal Disorders/diagnosis , Puerperal Disorders/etiology , Puerperal Disorders/therapy , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/therapy
4.
Appl Opt ; 59(10): 3285-3295, 2020 Apr 01.
Article in English | MEDLINE | ID: mdl-32400613

ABSTRACT

We present two prescriptions for broadband ($ {\sim} 77 - 252\;{\rm GHz} $), millimeter-wave antireflection coatings for cryogenic, sintered polycrystalline aluminum oxide optics: one for large-format (700 mm diameter) planar and plano-convex elements, the other for densely packed arrays of quasi-optical elements-in our case, 5 mm diameter half-spheres (called "lenslets"). The coatings comprise three layers of commercially available, polytetrafluoroethylene-based, dielectric sheet material. The lenslet coating is molded to fit the 150 mm diameter arrays directly, while the large-diameter lenses are coated using a tiled approach. We review the fabrication processes for both prescriptions, then discuss laboratory measurements of their transmittance and reflectance. In addition, we present the inferred refractive indices and loss tangents for the coating materials and the aluminum oxide substrate. We find that at 150 GHz and 300 K the large-format coating sample achieves $ (97 \pm 2)\% $ transmittance, and the lenslet coating sample achieves $ (94 \pm 3)\% $ transmittance.

5.
Vector Borne Zoonotic Dis ; 20(5): 348-357, 2020 05.
Article in English | MEDLINE | ID: mdl-31928511

ABSTRACT

Data on pathogen prevalence is crucial for informing exposure and disease risk. We evaluated serological evidence of tick-borne encephalitis (TBE), West Nile (WN), Hepatitis E virus (HEV), Crimean-Congo Hemorrhagic Fever (CCHF), Yersiniosis, Lyme Disease (LD), and brucellosis in 1033 patients presenting with acute febrile illness at 9 health care facilities from diverse ecological zones of Kenya: arid and semiarid (Garissa District Hospital, Lodwar District Hospital, Marigat District Hospital, Gilgil District Hospital), Lake Victoria basin (Kisumu District Hospital, Alupe District Hospital, Kombewa Sub-County Hospital), Kisii highland (Kisii District Hospital), and coastal (Malindi District Hospital). Epidemiological information of the patients such as geography, age, gender, and keeping animals were analyzed as potential risk factors. Of the 1033 samples, 619 (59.9%) were seropositive to at least one pathogen by IgM (current exposure), IgG/IgM (recent exposure), and IgG (past exposure). Collective seroprevalence for current, recent, and past to the pathogens was 9.4%, 5.1%, and 21.1% for LD; 3.6%, 0.5%, and 12.4% for WN; 0.9%, 0.5%, and 16.9% for HEV; 5.8%, 1.3%, and 3.9% for brucellosis; 5.7%, 0.2%, and 2.3% for yersiniosis; 1.7%, 0%, and 6.2% for TBE; and 0.4%, 0%, and 1.9% for CCHF. Brucellosis risk was higher in patients recruited at Garissa District Hospital (odds ratio [OR] = 3.41), HEV (OR = 2.45) and CCHF (OR = 5.46) in Lodwar District Hospital, LD in Alupe District Hospital (OR = 5.73), Kombewa Sub-district hospital (OR = 8.17), and Malindi District hospital (OR = 3.3). Exposure to LD was highest in the younger age group, whereas yersiniosis did not vary with age. Age was a significant risk for WN, brucellosis, CCHF, TBE, and HEV and in those aged >14 years there was an increased risk to WN (OR = 2.30, p < 0.0001), brucellosis (OR = 1.84, p = 0.005), CCHF (OR = 4.35, p = 0.001), TBE (OR = 2.78, p < 0.0001), and HEV (OR = 1.94, p = 0.0001). We conclude that LD is pervasive and constitutes a significant health burden to the study population, whereas yersiniosis and CCHF are not significant threats. Going forward, community-based studies will be needed to capture the true seroprevalence rates and the associated risk factors.


Subject(s)
Bacterial Infections/epidemiology , Bacterial Infections/microbiology , Virus Diseases/epidemiology , Virus Diseases/virology , Adolescent , Adult , Antibodies, Bacterial/blood , Antibodies, Viral/blood , Brucellosis/epidemiology , Child , Child, Preschool , Encephalitis, Tick-Borne/epidemiology , Female , Hemorrhagic Fever, Crimean/epidemiology , Hepatitis E/epidemiology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Infant , Kenya/epidemiology , Lyme Disease/epidemiology , Male , Seroepidemiologic Studies , West Nile Fever/epidemiology , Yersinia Infections/epidemiology , Young Adult
6.
Phys Rev Lett ; 123(18): 181301, 2019 Nov 01.
Article in English | MEDLINE | ID: mdl-31763885

ABSTRACT

We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes QU map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500 deg^{2} survey at the locations of roughly 18 000 clusters with richness λ≥10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8σ. The mean stacked mass of the selected sample is found to be (1.43±0.40)×10^{14}M_{⊙} which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements.

7.
Parasit Vectors ; 12(1): 295, 2019 Jun 11.
Article in English | MEDLINE | ID: mdl-31186055

ABSTRACT

BACKGROUND: Baseline information that is essential for determining the areas to target with larval control includes estimates of vector diversity and larval habitat preferences. Due to a lack of such information in Baringo County, Kenya, this study assessed species diversity and larval habitat preference of potential mosquito vectors of Rift Valley fever (RVF) and malaria. METHODS: Mosquito larvae were sampled from nine types of larval habitats and were identified morphologically. Species diversity was estimated by the Shannon's diversity index while larval habitat preference by RVF and malaria vectors was determined by ANOVA. RESULTS: A total of 7724 immature mosquitoes comprising 17 species belonging to four genera, namely Anopheles, Culex, Aedes and Mansonia, were identified. Among the 17 species, three Anopheles species are responsible for malaria transmission: An. gambiae (s.l.), An. funestus (s.l.) and An. pharoensis. Rift Valley fever vectors included Mansonia spp. and Culex spp. The highest Shannon's diversity index was observed during the cold dry season (H = 2.487) and in the highland zone (H = 2.539) while the lowest diversity was recorded during the long rain season (H = 2.354) and in the riverine zone (H = 2.085). Ditches had the highest mean number of Anopheles larvae (16.6 larvae per sample) followed by swamp (12.4) and seasonal riverbed (10.7). Water pit and water pan had low mean numbers of Anopheles larvae (1.4 and 1.8, respectively) but relatively high mean numbers of culicines (16.9 and 13.7, respectively). Concrete tank was the least sampled type of habitat but had highest mean number of culicine larvae (333.7 l) followed distantly by water spring (38.9) and swamp (23.5). Overall, larval habitats were significantly different in terms of larval density (F(8,334) = 2.090, P = 0.036). CONCLUSIONS: To our knowledge, the present study reports culicine larval species diversity in Baringo for the first time and the most preferred habitats were concrete tanks, water springs and swamps. Habitats preferred by Anopheles were mainly riverbed pools, ditches and swamps. Environmental management targeting the habitats most preferred by potential vectors can be part of integrated vector control in Baringo, especially during dry seasons.


Subject(s)
Biodiversity , Ecosystem , Mosquito Vectors/classification , Aedes/classification , Aedes/parasitology , Aedes/virology , Animals , Anopheles/classification , Anopheles/parasitology , Anopheles/virology , Culex/classification , Culex/parasitology , Culex/virology , Kenya , Larva , Mosquito Vectors/parasitology , Mosquito Vectors/virology , Plasmodium , Rift Valley fever virus , Seasons , Wetlands
8.
Matern Child Nutr ; 15(4): e12836, 2019 10.
Article in English | MEDLINE | ID: mdl-31045329

ABSTRACT

The impact of quality complementary food products on infant growth and body composition has not been adequately investigated. This study evaluated the effect on fat-free mass (FFM) accrual, linear growth, and iron status of locally produced complementary food products comparing to a standard product. In a randomized, double-blind trial, 499 infants at 6 months received nine monthly rations of (a) WinFood Classic (WFC) comprising germinated amaranth (71%), maize (10.4%), small fish (3%), and edible termites (10%); (b) WinFood Lite (WFL) comprising germinated amaranth (82.5%), maize (10.2%), and multimicronutrient premix; or (c) fortified corn-soy blend plus (CSB+). Primary outcomes were changes in FFM, length, and plasma ferritin and transferrin receptors (TfR). FFM was determined using deuterium dilution. Analysis was by intention to treat, based on available cases. Compared with CSB+, there were no differences in change from 6 to 15 months in FFM for WFC 0.0 kg (95% CI [-0.30, 0.29]) and WFL 0.03 kg (95% CI [-0.25, 0.32]) and length change for WFC -0.3 cm (95% CI [-0.9, 0.4]) and WFL -0.3 cm (95% CI [-0.9, 0.3]). TfR increased in WFC group 3.3 mg L-1 (95% CI [1.7, 4.9]) and WFL group 1.7 mg L-1 (95% CI [0.1, 3.4]) compared with CSB+. Compared with the increase in Hb in CSB+ group, there was a reduction in Hb in WFC of -0.9 g dl-1 (95% CI [-1.3, -0.5]) and a lower increase in WFL -0.4 g dl-1 (95% CI [-0.8, 0.0]). In conclusion, the tested WinFoods had the same effect on FFM and length as CSB+, whereas Hb and iron status decreased, suggesting inhibited iron bioavailability from the amaranth-based WinFoods.


Subject(s)
Body Composition/physiology , Body Height/physiology , Food, Fortified , Iron/blood , Diet , Double-Blind Method , Ferritins/blood , Humans , Infant , Iron/administration & dosage , Kenya , Micronutrients/administration & dosage
9.
J Intellect Disabil Res ; 62(11): 941-951, 2018 11.
Article in English | MEDLINE | ID: mdl-30125044

ABSTRACT

BACKGROUND: This study explored the role of demographic, psychosocial, stress and life event-related risk factors for psychopathology and challenging behaviour in a clinical sample of adults with Down syndrome. METHOD: A convenience sample of adults with Down syndrome seen through a specialised clinic was assessed through interviews and questionnaires specifically designed for use in people with intellectual disabilities. RESULTS: Recent negative life events and stressors were significantly correlated with mental and behavioural health, and significantly predicted irritability, lethargy and depressed mood. Social avoidance was predicted by stress related to anticipation and social-environmental stressors, and negatively predicted by verbal ability. Ritual-related stress predicted obsessive-compulsive behaviour. Participants who did not have a job or vocational placement were significantly more depressed than participants who did. CONCLUSIONS: Adults with Down syndrome should be provided increased supports for coping with negative life events and stressors. Interventions should also emphasise community engagement, such as employment, and access to psychosocial supports that teach coping and self-regulation skills when faced with stressors and negative life events.


Subject(s)
Affective Symptoms , Depression , Down Syndrome , Mental Disorders , Problem Behavior , Stress, Psychological , Adolescent , Adult , Affective Symptoms/epidemiology , Affective Symptoms/etiology , Affective Symptoms/physiopathology , Aged , Aged, 80 and over , Depression/complications , Depression/etiology , Depression/physiopathology , Down Syndrome/epidemiology , Down Syndrome/physiopathology , Female , Humans , Male , Mental Disorders/epidemiology , Mental Disorders/etiology , Mental Disorders/physiopathology , Middle Aged , Risk Factors , Stress, Psychological/complications , Stress, Psychological/epidemiology , Stress, Psychological/physiopathology , Young Adult
10.
PLoS One ; 13(7): e0199357, 2018.
Article in English | MEDLINE | ID: mdl-29975780

ABSTRACT

The global increase in vector borne diseases has been linked to climate change. Seasonal vegetation changes are known to influence disease vector population. However, the relationship is more theoretical than quantitatively defined. There is a growing demand for understanding and prediction of climate sensitive vector borne disease risks especially in regions where meteorological data are lacking. This study aimed at analyzing and quantitatively assessing the seasonal and year-to-year association between climatic factors (rainfall and temperature) and vegetation cover, and its implications for malaria risks in Baringo County, Kenya. Remotely sensed temperature, rainfall, and vegetation data for the period 2004-2015 were used. Poisson regression was used to model the association between malaria cases and climatic and environmental factors for the period 2009-2012, this being the period for which all datasets overlapped. A strong positive relationship was observed between the Normalized Difference Vegetation Index (NDVI) and monthly total precipitation. There was a strong negative relationship between NDVI and minimum temperature. The total monthly rainfall (between 94 -181mm), average monthly minimum temperatures (between 16-21°C) and mean monthly NDVI values lower than 0.35 were significantly associated with malaria incidence rates. Results suggests that a combination of climatic and vegetation greenness thresholds need to be met for malaria incidence to be significantly increased in the county. Planning for malaria control can therefore be enhanced by incorporating these factors in malaria risk mapping.


Subject(s)
Climate , Environment , Malaria/epidemiology , Geography , Humans , Incidence , Kenya , Malaria/prevention & control , Risk Assessment , Risk Factors , Seasons
11.
PLoS One ; 13(6): e0198970, 2018.
Article in English | MEDLINE | ID: mdl-29889888

ABSTRACT

Malaria, a major cause of morbidity and mortality, is the most prevalent vector borne disease in Baringo County; a region which has varied house designs in arid and semi-arid areas. This study investigated the association between house structures and indoor-malaria vector abundance in Baringo County. The density of malaria vectors in houses with open eaves was higher than that for houses with closed eaves. Grass thatched roof houses had higher density of malaria vectors than corrugated iron sheet roofs. Similarly, mud walled houses had higher vector density than other wall types. Houses in the riverine zone were significantly associated with malaria vector abundance (p<0.000) possibly due to more varied house structures. In Kamnarok village within riverine zone, a house made of grass thatched roof and mud wall but raised on stilts with domestic animals (sheep/goats) kept at the lower level had lower mosquito density (5.8 per collection) than ordinary houses made of same materials but at ground level (30.5 mosquitoes per collection), suggestive of a change in behavior of mosquito feeding and resting. House modifications such as screening of eaves, improvement of construction material and building stilted houses can be incorporated in the integrated vector management (IVM) strategy to complement insecticide treated bed nets and indoor residual spray to reduce indoor malaria vector density.


Subject(s)
Housing , Malaria/prevention & control , Animals , Anopheles/physiology , Humans , Kenya/epidemiology , Livestock/parasitology , Malaria/epidemiology , Mosquito Vectors , Sheep
12.
BMC Public Health ; 18(1): 609, 2018 05 09.
Article in English | MEDLINE | ID: mdl-29743062

ABSTRACT

BACKGROUND: The decline in global malaria cases is attributed to intensified utilization of primary vector control interventions and artemisinin-based combination therapies (ACTs). These strategies are inadequate in many rural areas, thus adopting locally appropriate integrated malaria control strategies is imperative in these heterogeneous settings. This study aimed at investigating trends and local knowledge on malaria and to develop a framework for malaria control for communities in Baringo, Kenya. METHODS: Clinical malaria cases obtained from four health facilities in the riverine and lowland zones were used to analyse malaria trends for the 2005-2014 period. A mixed method approach integrating eight focus group discussions, 12 key informant interviews, 300 survey questionnaires and two stakeholders' consultative forums were used to assess local knowledge on malaria risk and develop a framework for malaria reduction. RESULTS: Malaria cases increased significantly during the 2005-2014 period (tau = 0.352; p < 0.001) in the riverine zone. March, April, May, June and October showed significant increases compared to other months. Misconceptions about the cause and mode of malaria transmission existed. Gender-segregated outdoor occupation such as social drinking, farm activities, herding, and circumcision events increased the risk of mosquito bites. A positive relationship occurred between education level and opinion on exposure to malaria risk after dusk (χ2 = 2.70, p < 0.05). There was over-reliance on bed nets, yet only 68% (204/300) of respondents owned at least one net. Complementary malaria control measures were under-utilized, with 90% of respondents denying having used either sprays, repellents or burnt cow dung or plant leaves over the last one year before the study was conducted. Baraza, radios, and mobile phone messages were identified as effective media for malaria information exchange. Supplementary strategies identified included unblocking canals, clearing Prosopis bushes, and use of community volunteers and school clubs to promote social behaviour change. CONCLUSIONS: The knowledge gap on malaria transmission should be addressed to minimize the impacts and enhance uptake of appropriate malaria management mechanisms. Implementing community-based framework can support significant reductions in malaria prevalence by minimizing both indoor and outdoor malaria transmissions.


Subject(s)
Community Participation , Health Knowledge, Attitudes, Practice , Malaria/prevention & control , Mosquito Control/methods , Adult , Aged , Aged, 80 and over , Female , Focus Groups , Humans , Kenya/epidemiology , Malaria/epidemiology , Male , Middle Aged , Risk Assessment , Surveys and Questionnaires , Young Adult
13.
Malar J ; 16(1): 220, 2017 05 25.
Article in English | MEDLINE | ID: mdl-28545590

ABSTRACT

BACKGROUND: Malaria transmission in arid and semi-arid regions of Kenya such as Baringo County, is seasonal and often influenced by climatic factors. Unravelling the relationship between climate variables and malaria transmission dynamics is therefore instrumental in developing effective malaria control strategies. The main aim of this study was to describe the effects of variability of rainfall, maximum temperature and vegetation indices on seasonal trends of malaria in selected health facilities within Baringo County, Kenya. METHODS: Climate variables sourced from the International Research Institute (IRI)/Lamont-Doherty Earth Observatory (LDEO) climate database and malaria cases reported in 10 health facilities spread across four ecological zones (riverine, lowland, mid-altitude and highland) between 2004 and 2014 were subjected to a time series analysis. A negative binomial regression model with lagged climate variables was used to model long-term monthly malaria cases. The seasonal Mann-Kendall trend test was then used to detect overall monotonic trends in malaria cases. RESULTS: Malaria cases increased significantly in the highland and midland zones over the study period. Changes in malaria prevalence corresponded to variations in rainfall and maximum temperature. Rainfall at a time lag of 2 months resulted in an increase in malaria transmission across the four zones while an increase in temperature at time lags of 0 and 1 month resulted in an increase in malaria cases in the riverine and highland zones, respectively. CONCLUSION: Given the existence of a time lag between climatic variables more so rainfall and peak malaria transmission, appropriate control measures can be initiated at the onset of short and after long rains seasons.


Subject(s)
Climate Change , Malaria/epidemiology , Ecosystem , Humans , Kenya/epidemiology , Malaria/parasitology , Malaria/transmission , Models, Statistical , Models, Theoretical , Prevalence , Seasons
14.
Infect Ecol Epidemiol ; 6: 32322, 2016.
Article in English | MEDLINE | ID: mdl-27863533

ABSTRACT

BACKGROUND: Rift Valley fever (RVF) is a vector-borne zoonotic disease that has an impact on human health and animal productivity. Here, we explore the use of vector presence modelling to predict the distribution of RVF vector species under climate change scenario to demonstrate the potential for geographic spread of Rift Valley fever virus (RVFV). OBJECTIVES: To evaluate the effect of climate change on RVF vector distribution in Baringo County, Kenya, with an aim of developing a risk map for spatial prediction of RVF outbreaks. METHODOLOGY: The study used data on vector presence and ecological niche modelling (MaxEnt) algorithm to predict the effect of climatic change on habitat suitability and the spatial distribution of RVF vectors in Baringo County. Data on species occurrence were obtained from longitudinal sampling of adult mosquitoes and larvae in the study area. We used present (2000) and future (2050) Bioclim climate databases to model the vector distribution. RESULTS: Model results predicted potential suitable areas with high success rates for Culex quinquefasciatus, Culex univitattus, Mansonia africana, and Mansonia uniformis. Under the present climatic conditions, the lowlands were found to be highly suitable for all the species. Future climatic conditions indicate an increase in the spatial distribution of Cx. quinquefasciatus and M. africana. Model performance was statistically significant. CONCLUSION: Soil types, precipitation in the driest quarter, precipitation seasonality, and isothermality showed the highest predictive potential for the four species.

15.
BMC Infect Dis ; 16: 57, 2016 Feb 03.
Article in English | MEDLINE | ID: mdl-26842961

ABSTRACT

BACKGROUND: Schistosomes and soil-transmitted helminths (STH) (hookworm, Trichuris trichiura and Ascaris lumbricoides) are widely distributed in developing countries where they infect over 230 million and 1.5 billion people, respectively. The parasites are frequently co-endemic and many individuals are co-infected with two or more of the species, but information on how the parasites interact in co-infected individuals is scarce. The present study assessed Schistosoma haematobium and STH infection and morbidity patterns among school children in a hyper-endemic focus in the Tana River delta of coastal Kenya. METHODS: Two hundred and sixty-two children aged 5-12 years from two primary schools were enrolled in the study. For each child, urine was examined for S. haematobium eggs and haematuria, stool was examined for STH eggs, peripheral blood was examined for eosinophilia and haemoglobin level, the urinary tract was ultrasound-examined for S. haematobium-related pathology, and the height and weight was measured and used to calculate the body mass index (BMI). RESULTS: Prevalences of S. haematobium, hookworm, T. trichiura and A. lumbricoides infection were 94, 81, 88 and 46 %, respectively. There was no significant association between S. haematobium and STH infection but intensity of hookworm infection significantly increased with that of T. trichiura. Lower BMI scores were associated with high intensity of S. haematobium (difference =-0.48, p > 0.05) and A. lumbricoides (difference =-0.67, p < 0.05). Haematuria (both macro and micro) was common and associated with S. haematobium infection, while anaemia was associated with high intensity of S. haematobium (OR = 2.08, p < 0.05) and high hookworm infections OR = 4.75; p < 0.001). The majority of children had eosinophilia, which was significantly associated with high intensity of hookworm infection (OR = 5.34, p < 0.05). Overall 38 % of the children had ultrasound-detectable urinary tract morbidity, which was associated with high intensity of S. haematobium infection (OR = 3.13, p < 0.05). CONCLUSION: Prevalences of S. haematobium and STH infections among the primary school children were high and the parasites were responsible for significant morbidity. A clear synergistic interaction was observed between hookworm and T. trichiura infections. Increased coverage in administration of praziquantel and albendazole in the area is recommended to control morbidity due to these infections.


Subject(s)
Anthelmintics/therapeutic use , Helminthiasis/epidemiology , Schistosoma haematobium/isolation & purification , Schistosomiasis haematobia/epidemiology , Albendazole/therapeutic use , Ancylostomatoidea/isolation & purification , Anemia , Animals , Ascaris lumbricoides/isolation & purification , Child , Child, Preschool , Coinfection , Feces/parasitology , Female , Helminthiasis/drug therapy , Humans , Kenya/epidemiology , Male , Praziquantel/therapeutic use , Prevalence , Schistosomiasis haematobia/drug therapy , Schools , Soil/parasitology , Trichuris/isolation & purification
16.
BMC Infect Dis ; 14: 501, 2014 Sep 15.
Article in English | MEDLINE | ID: mdl-25223302

ABSTRACT

BACKGROUND: Pathological changes due to infection with Schistosoma haematobium include cytokine-mediated urinary tract inflammation. The involved cytokines may be excreted in urine and their presence in urine may therefore reflect S. haematobium-related urinary tract pathology. The present study, for the first time, reports on the relationship between selected cytokines in urine and infection with S. haematobium in children from an area highly affected by this parasite. METHODS: Children aged 5-12 years from two primary schools in Tana Delta District of Kenya were examined for S. haematobium eggs using urine filtration technique, for haematuria using dipstix and for eosinophil cationic protein (ECP), IL-6, IFN- γ, TNF-α and IL-10 levels using ELISA, and for S. haematobium-related urinary tract pathology using ultrasonography. In addition, venous blood was examined for serum IL-6, IFN- γ, TNF-α and IL-10 levels using ELISA. RESULTS: There was no significant correlation between urinary and serum levels of IL-6, IFN- γ, TNF-α or IL-10. There was no significant difference in geometric mean intensity (GMI) in any of the serum cytokines, or in urinary TNF-α or IFN-γ, between children with light and heavy S. haematobium infections. However, children with heavy S. haematobium infections had significantly higher GMI of urinary IL-6 (p < 0.001) and lower GMI of urinary IL-10 (p = 0.002) than children with light infections. There was also a significant positive correlation between urinary IL-6 and urinary ECP (p < 0.001) and a significant negative correlation between urinary IL-10 and urinary ECP (p = 0.012). CONCLUSION: Urinary IL-6 was positively correlated to and IL-10 was negatively correlated to infection intensity and urinary tract inflammation in S. haematobium-infected children. Urinary IL-6 and IL-10 ELISA may be a useful non-invasive tool to complement the already available tools for studying S. haematobium-related urinary tract pathology in children.


Subject(s)
Cytokines/urine , Schistosomiasis haematobia/urine , Adolescent , Animals , Child , Child, Preschool , Cross-Sectional Studies , Cytokines/blood , Enzyme-Linked Immunosorbent Assay , Female , Hematuria/blood , Humans , Inflammation , Interleukin-10/blood , Interleukin-10/urine , Interleukin-6/blood , Interleukin-6/urine , Kenya , Male , Parasite Egg Count , Schistosoma haematobium , Schistosomiasis haematobia/parasitology , Tumor Necrosis Factor-alpha/blood , Tumor Necrosis Factor-alpha/urine
17.
Brain Cogn ; 89: 51-60, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24485273

ABSTRACT

Adolescent risk-taking behavior has been associated with age-related changes in striatal activation to incentives. Previous cross-sectional studies have shown both increased and decreased striatal activation to incentives for adolescents compared to adults. The monetary incentive delay (MID) task, designed to assess functional brain activation in anticipation of reward, has been used extensively to examine striatal activation in both adult and adolescent populations. The current study used this task with a longitudinal approach across mid-adolescence and late adolescence/early adulthood. Twenty-two participants (13 male) were studied using the MID task at two time-points, once in mid-adolescence (mean age=16.11; SD=1.44) and a second time in late adolescence/early adulthood (mean age=20.14; SD=.67). Results revealed greater striatal activation with increased age in high- compared to low-incentive contexts (incentive magnitude), for gain as well as for loss trials (incentive valence). Results extend cross-sectional findings and show reduced striatal engagement in adolescence compared to adulthood during preparation for action in an incentive context.


Subject(s)
Anticipation, Psychological/physiology , Corpus Striatum/physiology , Reward , Adolescent , Adult , Age Factors , Brain Mapping , Corpus Striatum/growth & development , Female , Humans , Longitudinal Studies , Magnetic Resonance Imaging , Male , Motivation/physiology , Reaction Time , Young Adult
18.
Phys Rev Lett ; 111(14): 141301, 2013 Oct 04.
Article in English | MEDLINE | ID: mdl-24138230

ABSTRACT

Gravitational lensing of the cosmic microwave background generates a curl pattern in the observed polarization. This "B-mode" signal provides a measure of the projected mass distribution over the entire observable Universe and also acts as a contaminant for the measurement of primordial gravity-wave signals. In this Letter we present the first detection of gravitational lensing B modes, using first-season data from the polarization-sensitive receiver on the South Pole Telescope (SPTpol). We construct a template for the lensing B-mode signal by combining E-mode polarization measured by SPTpol with estimates of the lensing potential from a Herschel-SPIRE map of the cosmic infrared background. We compare this template to the B modes measured directly by SPTpol, finding a nonzero correlation at 7.7σ significance. The correlation has an amplitude and scale dependence consistent with theoretical expectations, is robust with respect to analysis choices, and constitutes the first measurement of a powerful cosmological observable.

19.
BMC Infect Dis ; 13: 263, 2013 Jun 04.
Article in English | MEDLINE | ID: mdl-23734875

ABSTRACT

BACKGROUND: HIV-1-related inflammation is associated with increased levels of biomarkers of vascular adhesion and endothelial activation, and may increase production of the inflammatory protein angiopoietin-2 (ANG-2), an adverse prognostic biomarker in severe systemic infection. We hypothesized that antiretroviral therapy (ART) initiation would decrease endothelial activation, reducing plasma levels of ANG-2. METHODS: Antiretroviral-naïve Kenyan women with advanced HIV infection were followed prospectively. Endothelial activation biomarkers including soluble intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and E-selectin, and plasma ANG-2 and angiopoietin-1 (ANG-1) were tested in stored plasma samples from 0, 6, and 12 months after ART initiation. We used Wilcoxon matched-pairs signed rank tests to compare endothelial activation biomarkers across time-points, generalized estimating equations to analyze associations with change in log10-transformed biomarkers after ART initiation, and Cox proportional-hazards regression to analyze associations with mortality. RESULTS: The 102 HIV-1-seropositive women studied had advanced infection (median CD4 count, 124 cells/µL). Soluble ICAM-1 and plasma ANG-2 levels decreased at both time-points after ART initiation, with concomitant increases in the beneficial protein ANG-1. Higher ANG-2 levels after ART initiation were associated with higher plasma HIV-1 RNA, oral contraceptive pill use, pregnancy, severe malnutrition, and tuberculosis. Baseline ANG-2 levels were higher among five women who died after ART initiation than among women who did not (median 2.85 ng/mL [inter-quartile range (IQR) 2.47-5.74 ng/mL] versus median 1.32 ng/mL [IQR 0.35-2.18 ng/mL], p = 0.01). Both soluble ICAM-1 and plasma ANG-2 levels predicted mortality after ART initiation. CONCLUSIONS: Biomarkers of endothelial activation decreased after ART initiation in women with advanced HIV-1 infection. Changes in plasma ANG-2 were associated with HIV-1 RNA levels over 12 months of follow-up. Soluble ICAM-1 and plasma ANG-2 levels represent potential biomarkers for adverse outcomes in advanced HIV-1 infection.


Subject(s)
Angiopoietin-1/blood , Angiopoietin-2/blood , Anti-Retroviral Agents/therapeutic use , HIV Infections/blood , HIV Infections/drug therapy , HIV-1/isolation & purification , Adult , Antiretroviral Therapy, Highly Active , Biomarkers/blood , Cell Adhesion Molecules/blood , Female , Humans , Kenya , Male , Pregnancy , Prospective Studies
20.
AIDS ; 27(11): 1803-13, 2013 Jul 17.
Article in English | MEDLINE | ID: mdl-23807276

ABSTRACT

OBJECTIVE: We aimed to determine whether endothelial activation biomarkers increase after HIV-1 acquisition, and whether biomarker levels measured in chronic infection would predict disease progression and death in HIV-1 seroconverters. DESIGN: HIV-1-seronegative Kenyan women were monitored monthly for seroconversion, and followed prospectively after HIV-1 acquisition. METHODS: Plasma levels of angiopoietin-1 and angiopoietin-2 (ANG-1, ANG-2) and soluble vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin were tested in stored samples from pre-infection, acute infection, and two chronic infection time points. We used nonparametric tests to compare biomarkers before and after HIV-1 acquisition, and Cox proportional-hazards regression to analyze associations with disease progression (CD4 < 200 cells/µl, stage IV disease, or antiretroviral therapy initiation) or death. RESULTS: Soluble ICAM-1 and VCAM-1 were elevated relative to baseline in all postinfection periods assessed (P < 0.0001). Soluble E-selectin and the ANG-2:ANG-1 ratio increased in acute infection (P = 0.0001), and ANG-1 decreased in chronic infection (P = 0.0004). Among 228 participants followed over 1028 person-years, 115 experienced disease progression or death. Plasma VCAM-1 levels measured during chronic infection were independently associated with time to HIV progression or death (adjusted hazard ratio 5.36, 95% confidence interval 1.99-14.44 per log10 increase), after adjustment for set point plasma viral load, age at infection, and soluble ICAM-1 levels. CONCLUSION: HIV-1 acquisition was associated with endothelial activation, with sustained elevations of soluble ICAM-1 and VCAM-1 postinfection. Soluble VCAM-1 may be an informative biomarker for predicting the risk of HIV-1 disease progression, morbidity, and mortality.


Subject(s)
Biomarkers/blood , HIV Infections/pathology , Vascular Cell Adhesion Molecule-1/blood , Adult , Angiopoietin-1/blood , Angiopoietin-2/blood , CD4 Lymphocyte Count , Disease Progression , E-Selectin/blood , Female , Follow-Up Studies , HIV Infections/virology , HIV-1/isolation & purification , Humans , Intercellular Adhesion Molecule-1/blood , Kenya , Plasma/chemistry , Prospective Studies , Survival Analysis
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