scholarly journals A novel vehicle-mounted sticky trap; an effective sampling tool for savannah tsetse flies Glossina morsitans morsitans Westwood and Glossina morsitans centralis Machado

2021 ◽  
Vol 15 (7) ◽  
pp. e0009620
Author(s):  
Jackson Muyobela ◽  
Christian W. W. Pirk ◽  
Abdullahi A. Yusuf ◽  
Njelembo J. Mbewe ◽  
Catherine L. Sole
Keyword(s):  
Negative Binomial ◽  
Block Design ◽  
Negative Binomial Regression ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Rapid Sampling ◽  
Glossina Morsitans Centralis ◽  
Binomial Regression ◽  
Design Experiments

Background Black screen fly round (BFR) is a mobile sampling method for Glossina morsitans. This technique relies on the ability of operator(s) to capture flies landing on the screen with hand nets. In this study, we aimed to evaluate a vehicle-mounted sticky panel trap (VST) that is independent of the operator’s ability to capture flies against BFR, for effective and rapid sampling of G. m. morsitans Westwood and G. m. centralis Machado. We also determined the influence of the VST colour (all-blue, all-black or 1:1 blue-black), orientation and presence of odour attractants on tsetse catch. Methodology/Principal findings Using randomised block design experiments conducted in Zambia, we compared and modelled the number of tsetse flies caught in the treatment arms using negative binomial regression. There were no significant differences in the catch indices of the three colour designs and for in-line or transversely oriented panels for both subspecies (P > 0.05). When baited with butanone and 1-octen-3-ol, VST caught 1.38 (1.11–1.72; P < 0.01) times more G. m. centralis flies than the un-baited trap. Attractants did not significantly increase the VST catch index for G. m. morsitans (P > 0.05). Overall, the VST caught 2.42 (1.91–3.10; P < 0.001) and 2.60 (1.50–3.21; P < 0.001) times more G. m. centralis and G. m. morsitans respectively, than the BFR. The VST and BFR took 10 and 35 min respectively to cover a 1 km transect. Conclusion/Significance The VST is several times more effective for sampling G. m. morsitans and G. m. centralis than the BFR and we recommend its use as an alternative sampling tool.

Infection of post-teneral tsetse flies (Glossina morsitans morsitans and Glossina morsitans centralis) with Trypanosoma brucei brucei

1988 ◽  
Vol 66 (6) ◽  
pp. 1289-1292 ◽  
Author(s):  
R. H. Gooding
Keyword(s):  
Trypanosoma Brucei ◽  
Significant Proportion ◽  
Glossina Morsitans Morsitans ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Trypanosoma Brucei Brucei ◽  
Male And Female ◽  
Glossina Morsitans Centralis

A significant proportion of post-teneral male Glossina morsitans morsitans Westwood and post-teneral male and female Glossina morsitans centralis Machado develop mature infections of Trypanosoma brucei brucei Plimmer and Bradford without being starved before feeding upon infected rabbits.

Postmating barriers to gene flow among species and subspecies of tsetse flies (Diptera: Glossinidae)

1990 ◽  
Vol 68 (8) ◽  
pp. 1727-1734 ◽  
Author(s):  
R. H. Gooding
Keyword(s):  
Gene Flow ◽  
Glossina Morsitans Morsitans ◽  
The Other ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Closely Related Species ◽  
X Chromosomes ◽  
Naturally Occurring ◽  
Y Chromosomes ◽  
Glossina Morsitans Centralis

Postmating barriers to gene flow between closely related species and subspecies of tsetse flies include (i) reduced fecundity of hybridized and hybrid females and (ii) sterility of hybrid and backcross males, owing mainly to incompatibility between X and Y chromosomes from two different taxa or, possibly, incompatibility between the X from one taxon and autosomes from the other. There are also maternally inherited factors that confer unidirectional sterility upon males; these factors may influence the direction of gene flow. When Glossina morsitans morsitans and Glossina morsitans centralis are crossed, these factors appear to be unstable and lose their effectiveness as barriers to gene flow when hybrid females, from several consecutive generations, are backcrossed to G. m. centralis. In hybrid females of the morsitans group, intrachromosomal recombination is suppressed in the X chromosomes, but it may occur at near normal levels in at least part of linkage group II. Some backcross flies with chromosomes composed of segments from two different taxa are fertile. Naturally occurring hybrids have been found, but it appears that hybridization zones are narrow. It remains to be determined whether introgression of genes plays a significant role in the evolution of tsetse flies.

Electrophoretic and hybridization comparison of Glossina morsitans morsitans, G. m. centralis, and G. m. submorsitans (Diptera: Glossinidae)

1985 ◽  
Vol 63 (11) ◽  
pp. 2694-2702 ◽  
Author(s):  
R. H. Gooding
Keyword(s):  
Geographic Location ◽  
Glossina Morsitans Morsitans ◽  
Allele Frequencies ◽  
Genetic Identity ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Glossina Morsitans Submorsitans ◽  
Glossina Morsitans Centralis ◽  
Identity Based

Two colonies of Glossina morsitans morsitans Westwood, two colonies of Glossina morsitans submorsitans Newstead, and one colony of Glossina morsitans centralis Machado, each originating from a different geographic location, were compared genetically and by their ability to hybridize. There were marked asymmetries in results of intersubspecific hybridization. Most F1 males were sterile but most F1 females were fertile. Nei's mean genetic identity (based on 12 loci) and four hybridization indices (based upon proportion of females fertilized, puparia produced per fertilized female, F1 adults per fertilized female, and proportion of females fertilized in backcross experiments) yielded the same results: intrasubspecific similarities are greater than intersubspecific similarities, and G. m. centralis is more similar to G. m. morsitans than it is to G. m. submorsitans. Evidence is presented indicating that a phenogram based upon allele frequencies is as good as phenograms based upon hybridization as a means of representing relationships among tsetse flies.

scholarly journals Is area deprivation associated with greater impacts of COVID-19 in care homes across England? A preliminary analysis of COVID-19 outbreaks and deaths

2021 ◽  
pp. jech-2020-215039 ◽  
Author(s):  
Anders Malthe Bach-Mortensen ◽  
Michelle Degli Esposti
Keyword(s):  
Negative Binomial ◽  
Care Home ◽  
Negative Binomial Regression ◽  
Population Characteristics ◽  
Care Homes ◽  
Future Research ◽  
Area Deprivation ◽  
Binomial Regression ◽  
Index Of Multiple Deprivation

IntroductionThe COVID-19 pandemic has disproportionately impacted care homes and vulnerable populations, exacerbating existing health inequalities. However, the role of area deprivation in shaping the impacts of COVID-19 in care homes is poorly understood. We examine whether area deprivation is linked to higher rates of COVID-19 outbreaks and deaths among care home residents across upper tier local authorities in England (n=149).MethodsWe constructed a novel dataset from publicly available data. Using negative binomial regression models, we analysed the associations between area deprivation (Income Deprivation Affecting Older People Index (IDAOPI) and Index of Multiple Deprivation (IMD) extent) as the exposure and COVID-19 outbreaks, COVID-19-related deaths and all-cause deaths among care home residents as three separate outcomes—adjusting for population characteristics (size, age composition, ethnicity).ResultsCOVID-19 outbreaks in care homes did not vary by area deprivation. However, COVID-19-related deaths were more common in the most deprived quartiles of IDAOPI (incidence rate ratio (IRR): 1.23, 95% CI 1.04 to 1.47) and IMD extent (IRR: 1.16, 95% CI 1.00 to 1.34), compared with the least deprived quartiles.DiscussionThese findings suggest that area deprivation is a key risk factor in COVID-19 deaths among care home residents. Future research should look to replicate these results when more complete data become available.

scholarly journals Association between fatality rate of COVID-19 and selenium deficiency in China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hai-Yang Zhang ◽  
An-Ran Zhang ◽  
Qing-Bin Lu ◽  
Xiao-Ai Zhang ◽  
Zhi-Jie Zhang ◽  
...  
Keyword(s):  
Negative Binomial ◽  
Viral Infections ◽  
Case Fatality ◽  
Selenium Deficiency ◽  
Negative Binomial Regression ◽  
Negative Binomial Regression Model ◽  
Fatality Rate ◽  
Selenium Content ◽  
Individual Level ◽  
Binomial Regression

Abstract Background COVID-19 has impacted populations around the world, with the fatality rate varying dramatically across countries. Selenium, as one of the important micronutrients implicated in viral infections, was suggested to play roles. Methods An ecological study was performed to assess the association between the COVID-19 related fatality and the selenium content both from crops and topsoil, in China. Results Totally, 14,045 COVID-19 cases were reported from 147 cities during 8 December 2019–13 December 2020 were included. Based on selenium content in crops, the case fatality rates (CFRs) gradually increased from 1.17% in non-selenium-deficient areas, to 1.28% in moderate-selenium-deficient areas, and further to 3.16% in severe-selenium-deficient areas (P = 0.002). Based on selenium content in topsoil, the CFRs gradually increased from 0.76% in non-selenium-deficient areas, to 1.70% in moderate-selenium-deficient areas, and further to 1.85% in severe-selenium-deficient areas (P < 0.001). The zero-inflated negative binomial regression model showed a significantly higher fatality risk in cities with severe-selenium-deficient selenium content in crops than non-selenium-deficient cities, with incidence rate ratio (IRR) of 3.88 (95% CIs: 1.21–12.52), which was further confirmed by regression fitting the association between CFR of COVID-19 and selenium content in topsoil, with the IRR of 2.38 (95% CIs: 1.14–4.98) for moderate-selenium-deficient cities and 3.06 (1.49–6.27) for severe-selenium-deficient cities. Conclusions Regional selenium deficiency might be related to an increased CFR of COVID-19. Future studies are needed to explore the associations between selenium status and disease outcome at individual-level.

scholarly journals Statistical models for analyzing count data: predictors of length of stay among HIV patients in Portugal using a multilevel model

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ahmed Nabil Shaaban ◽  
Bárbara Peleteiro ◽  
Maria Rosario O. Martins
Keyword(s):  
Length Of Stay ◽  
Regression Model ◽  
Random Effects ◽  
Count Data ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Comprehensive Approach ◽  
Negative Binomial Regression Model ◽  
Hiv Patients ◽  
Binomial Regression

Abstract Background This study offers a comprehensive approach to precisely analyze the complexly distributed length of stay among HIV admissions in Portugal. Objective To provide an illustration of statistical techniques for analysing count data using longitudinal predictors of length of stay among HIV hospitalizations in Portugal. Method Registered discharges in the Portuguese National Health Service (NHS) facilities Between January 2009 and December 2017, a total of 26,505 classified under Major Diagnostic Category (MDC) created for patients with HIV infection, with HIV/AIDS as a main or secondary cause of admission, were used to predict length of stay among HIV hospitalizations in Portugal. Several strategies were applied to select the best count fit model that includes the Poisson regression model, zero-inflated Poisson, the negative binomial regression model, and zero-inflated negative binomial regression model. A random hospital effects term has been incorporated into the negative binomial model to examine the dependence between observations within the same hospital. A multivariable analysis has been performed to assess the effect of covariates on length of stay. Results The median length of stay in our study was 11 days (interquartile range: 6–22). Statistical comparisons among the count models revealed that the random-effects negative binomial models provided the best fit with observed data. Admissions among males or admissions associated with TB infection, pneumocystis, cytomegalovirus, candidiasis, toxoplasmosis, or mycobacterium disease exhibit a highly significant increase in length of stay. Perfect trends were observed in which a higher number of diagnoses or procedures lead to significantly higher length of stay. The random-effects term included in our model and refers to unexplained factors specific to each hospital revealed obvious differences in quality among the hospitals included in our study. Conclusions This study provides a comprehensive approach to address unique problems associated with the prediction of length of stay among HIV patients in Portugal.

scholarly journals Association between breakfast skipping and metabolic outcomes by sex, age, and work status stratification

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jun Heo ◽  
Won-Jun Choi ◽  
Seunghon Ham ◽  
Seong-Kyu Kang ◽  
Wanhyung Lee
Keyword(s):  
Regression Analysis ◽  
Negative Binomial ◽  
Metabolic Diseases ◽  
Young Male ◽  
Negative Binomial Regression ◽  
Final Analysis ◽  
Work Status ◽  
Breakfast Skipping ◽  
Metabolic Outcomes ◽  
Binomial Regression

Abstract Background The association between breakfast skipping and abnormal metabolic outcomes remains controversial. A comprehensive study with various stratified data is required. Objective The aim of this study was to investigate the relationship between abnormal metabolic outcomes and breakfast skipping by sex, age, and work status stratification. Methods We used data from the Korea National Health and Nutrition Examination Surveys from 2013 to 2018. A total of 21,193 (9022 men and 12,171 women) participants were included in the final analysis. The risk of metabolic outcomes linked to breakfast skipping was estimated using the negative binomial regression analysis by sex, work status, and age stratification. Results A total of 11,952 (56.4%) participants consumed breakfast regularly. The prevalence of abnormal metabolic outcomes was higher among those with irregular breakfast consumption habits. Among young male workers, negative binomial regression analysis showed that irregular breakfast eaters had a higher risk of abnormal metabolic outcomes, after adjusting for covariates (odds ratio, 1.15; 95% confidence interval, 1.03–1.27). Conclusions The risk of abnormal metabolic outcomes was significant in young men in the working population. Further studies are required to understand the association of specific working conditions (working hours or shift work) with breakfast intake status and the risk of metabolic diseases.

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