scholarly journals Spatial and genomic data to characterize endemic typhoid transmission

2021 ◽  
Author(s):  
Jillian S Gauld ◽  
Franziska Olgemoeller ◽  
Eva Heinz ◽  
Rose Nkhata ◽  
Sithembile Bilima ◽  
...  
Keyword(s):  
Typhoid Fever ◽  
Spatial Data ◽  
Control Strategies ◽  
Salmonella Typhi ◽  
Modeling Framework ◽  
Single Nucleotide ◽  
High Incidence ◽  
Transmission Pathways ◽  
The City ◽  
Queen Elizabeth Central Hospital

Abstract Background Diverse environmental exposures and risk factors have been implicated in the transmission of Salmonella Typhi, however, the dominant transmission pathways through the environment to susceptible humans remain unknown. Here, we utilize spatial, bacterial genomic, and hydrological data to refine our view of Typhoid transmission in an endemic setting. Methods 546 patients presenting to Queen Elizabeth Central Hospital in Blantyre, Malawi with blood culture-confirmed typhoid fever between April 2015 and January 2017 were recruited to a cohort study. The households of a subset of these patients were geolocated, and 256 S. Typhi isolates were whole genome sequenced. Pairwise single nucleotide variant (SNV) distances were incorporated into a geostatistical modeling framework using multidimensional scaling. Results Typhoid fever was not evenly distributed across Blantyre, with estimated minimum incidence ranging across the city from less than 15 to over 100 cases/100,000/year. Pairwise SNV distance and physical household distances were significantly correlated (p=0.001). We evaluated the ability of river catchment to explain the spatial patterns of genomics observed, finding that it significantly improved the fit of the model (p=0.003). We also found spatial correlation at a smaller spatial scale, of households living <192 meters apart. Conclusions These findings reinforce the emerging view that hydrological systems play a key role in the transmission of typhoid fever. By combining genomic and spatial data, we show how multi-faceted data can be used to identify high incidence areas, understand the connections between them, and inform targeted environmental surveillance, all of which will be critical to shape local and regional typhoid control strategies.

scholarly journals Prevalence and Associated Risk Factors of Typhoid Fever in Children Attending “Deo Gratias” Hospital in Douala, Littoral Region

2020 ◽  
Author(s):  
Teh Exodus Akwa ◽  
Nguimbous Simone
Keyword(s):  
Risk Factors ◽  
Risk Factor ◽  
Typhoid Fever ◽  
Communicable Disease ◽  
Control Strategies ◽  
Salmonella Typhi ◽  
Health Concern ◽  
Cross Sectional ◽  
Significant Difference ◽  
Associated Risk Factors

Typhoid fever is a communicable disease transmitted by the bacteria Salmonella typhi, related to serotype paratyphi A, B and C. The disease is of a significant health concern in most developing countries especially Cameroon. Objectives: The study aimed at determining the prevalence and associated risk factors of typhoid fever in children ( 0-18 years) attending the “Deo Gratias” hospital in Douala. Method: A hospital base cross sectional study from August to September 2018 was carried out in patients’ age 0-18 years suffering from typhoid fever at the Deo gratias Catholic hospital. Widal slide agglutination test was the diagnostic test used. Positive tested patients were administered questionnaires to evaluate the level of knowledge, attitude and practice toward the disease, as well as their self-management abilities. Data obtained from respondents was analysed by descriptive statistics. One-way ANOVA and means comparison using Tukey’s test (α = 0.05) was performed to check whether the population of respondents differed significantly across risk factor practices. Results were finally presented on bar charts, tables and pie chart. Results: Typhoid fever was more prevalent in females (52.3%) than in males (47.7%), with a high proportion in the ages 5-9 years (38.6%). A significant difference was observed in population of respondents across risk factor practices. Conclusion: Water quality have a great impact on the burden of typhoid fever among children. The identification of risk factors associated to the disease is of great importance in the development of rational control strategies of the disease.

Improved Oxygen Dissolution Control for Oxygen Activated Sludge

1988 ◽  
Vol 20 (4-5) ◽  
pp. 101-108 ◽  
Author(s):  
R. C. Clifft ◽  
M. T. Garrett
Keyword(s):  
Activated Sludge ◽  
Control Method ◽  
Control Strategies ◽  
Cost Savings ◽  
Utilization Efficiency ◽  
Oxygen Production ◽  
Oxygen Utilization ◽  
Potential Cost ◽  
Oxygen Dissolution ◽  
The City

Now that oxygen production facilities can be controlled to match the requirements of the dissolution system, improved oxygen dissolution control can result in significant cost savings for oxygen activated sludge plants. This paper examines the potential cost savings of the vacuum exhaust control (VEC) strategy for the City of Houston, Texas 69th Street Treatment Complex. The VEC strategy involves operating a closed-tank reactor slightly below atmospheric pressure and using an exhaust apparatus to remove gas from the last stage of the reactor. Computer simulations for one carbonaceous reactor at the 69th Street Complex are presented for the VEC and conventional control strategies. At 80% of design loading the VEC strategy was found to provide an oxygen utilization efficiency of 94.9% as compared to 77.0% for the conventional control method. At design capacity the oxygen utilization efficiency for VEC and conventional control was found to be 92.3% and 79.5%, respectively. Based on the expected turn-down capability of Houston's oxygen production faciilities, the simulations indicate that the VEC strategy will more than double the possible cost savings of the conventional control method.

scholarly journals Waterlogging Risk Assessment: An Undervalued Disaster Risk in Coastal Urban Community of Chattogram, Bangladesh

Earth ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 151-173
Author(s):  
Md. Rezuanul Islam ◽  
Debasish Roy Raja
Keyword(s):  
Spatial Data ◽  
Risk Index ◽  
Structural Data ◽  
Economic Loss ◽  
Primary Objective ◽  
Social Infrastructure ◽  
Simple Method ◽  
City Area ◽  
Inventory Map ◽  
The City

In recent years, rainfall-induced waterlogging has become a common hazard in the highly urbanized coastal city of Chattogram, Bangladesh, resulting in a high magnitude of property damage and economic loss. Therefore, the primary objective of this research was to prepare a waterlogging inventory map and understand the spatial variations of the risk by means of hazard intensity, exposure, and vulnerability of waterlogging. In this research, the inventory map and factors influencing waterlogging hazards were determined from a participatory survey, and other spatial data, including land elevation, population, and structural data, were collected from secondary sources. The analytical hierarchy process was applied to measure the hazard intensity, and the exposure and vulnerability were estimated by overlaying the spatial data onto the hazard intensity map. A total of 58 locations were identified as waterlogging affected, which covered ~8.42% of the city area. We showed that ~3.03% of the city area was greatly vulnerable to waterlogging in terms of their social, infrastructure, critical facilities, economic, and environmental vulnerabilities. The obtained waterlogging risk index map suggested that ~2.71% of the study area was at very high risk, followed by moderate (~0.15%), low (~3.89%), and very low (~1.67%). The risk analysis presented in this study was a simple method that can be applied to assess the relative risk of waterlogging in different regions, and the results were applicable to the prevention and mitigation of waterlogging for Chattogram City.

scholarly journals High insecticide resistance mediated by different mechanisms in Culex quinquefasciatus populations from the city of Yaoundé, Cameroon

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdou Talipouo ◽  
Konstantinos Mavridis ◽  
Elysée Nchoutpouen ◽  
Borel Djiappi-Tchamen ◽  
Emmanouil Alexandros Fotakis ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Vector Control ◽  
High Resistance ◽  
Culex Quinquefasciatus ◽  
Control Strategies ◽  
Cuticular Hydrocarbon ◽  
Control Measures ◽  
High Frequencies ◽  
The City ◽  
Integrated Vector Control

AbstractCulex mosquitoes particularly Culex quinquefasciatus are important arboviral and filariasis vectors, however despite this important epidemiological role, there is still a paucity of data on their bionomics. The present study was undertaken to assess the insecticide resistance status of Cx. quinquefasciatus populations from four districts of Yaoundé (Cameroon). All Culex quinquefasciatus populations except one displayed high resistance to bendiocarb and malathion with mortalities ranging from 0 to 89% while high resistance intensity against both permethrin and deltamethrin was recorded. Molecular analyses revealed high frequencies of the ACE-1 G119S mutation (ranging from 0 to 33%) and kdr L1014F allele (ranging from 55 to 74%) in all Cx. quinquefasciatus populations. Significant overexpression was detected for cytochrome P450s genes CYP6AA7 and CYP6Z10, as well as for Esterase A and Esterase B genes. The total cuticular hydrocarbon content, a proxy of cuticular resistance, was significantly increased (compared to the S-lab strain) in one population. The study confirms strong insecticide resistance mediated by different mechanisms in Cx. quinquefasciatus populations from the city of Yaoundé. The expansion of insecticide resistance in Culex populations could affect the effectiveness of current vector control measures and stress the need for the implementation of integrated vector control strategies in urban settings.

scholarly journals Stool shedding of Salmonella Typhi in children with blood culture-confirmed typhoid fever

2020 ◽  
Vol 101 ◽  
pp. 123
Author(s):  
M. Srinivasan ◽  
S. Giri ◽  
S. Kulandaipalayam Natarajan ◽  
N. Kumar ◽  
V.R. Mohan ◽  
...  
Keyword(s):  
Blood Culture ◽  
Typhoid Fever ◽  
Salmonella Typhi

scholarly journals A modeling study to inform screening and testing interventions for the control of SARS-CoV-2 on university campuses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ben Lopman ◽  
Carol Y. Liu ◽  
Adrien Le Guillou ◽  
Andreas Handel ◽  
Timothy L. Lash ◽  
...  
Keyword(s):  
Cumulative Incidence ◽  
Disease Surveillance ◽  
Control Strategies ◽  
Transmission Model ◽  
University Administrators ◽  
Modeling Framework ◽  
University Campuses ◽  
School Year ◽  
Flexible Modeling ◽  
Resource Requirements

AbstractUniversity administrators face decisions about how to safely return and maintain students, staff and faculty on campus throughout the 2020–21 school year. We developed a susceptible-exposed-infectious-recovered (SEIR) deterministic compartmental transmission model of SARS-CoV-2 among university students, staff, and faculty. Our goals were to inform planning at our own university, Emory University, a medium-sized university with around 15,000 students and 15,000 faculty and staff, and to provide a flexible modeling framework to inform the planning efforts at similar academic institutions. Control strategies of isolation and quarantine are initiated by screening (regardless of symptoms) or testing (of symptomatic individuals). We explored a range of screening and testing frequencies and performed a probabilistic sensitivity analysis. We found that among students, monthly and weekly screening can reduce cumulative incidence by 59% and 87%, respectively, while testing with a 2-, 4- and 7-day delay between onset of infectiousness and testing results in an 84%, 74% and 55% reduction in cumulative incidence. Smaller reductions were observed among staff and faculty. Community-introduction of SARS-CoV-2 onto campus may be controlled with testing, isolation, contract tracing and quarantine. Screening would need to be performed at least weekly to have substantial reductions beyond disease surveillance. This model can also inform resource requirements of diagnostic capacity and isolation/quarantine facilities associated with different strategies.

scholarly journals Typh fevers: a combination of Typhoid and Typhus

2017 ◽  
Vol 8 (6) ◽  
pp. 40-41
Author(s):  
Robin George Manappallil
Keyword(s):  
Typhoid Fever ◽  
Similar Pattern ◽  
Salmonella Typhi ◽  
Young Lady ◽  
Medical Sciences ◽  
Rickettsial Infection ◽  
History Of ◽  
Typhus Fever

Typhoid fever is caused by Salmonella typhi, while typhus fever is a rickettsial infection. In both cases the patients present with almost similar pattern of illness and are often misdiagnosed. This is the case of a young lady who presented with 10 days history of fever and was diagnosed to have typhoid fever. She continued to be febrile despite ceftriaxone therapy. She was later found to have a typhus coinfection and improved with addition of doxycycline.Asian Journal of Medical Sciences Vol.8(6) 2017 40-41

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