scholarly journals Genetic evidence for imported malaria and local transmission in Richard Toll, Senegal

2020 ◽  
Author(s):  
Sarah K. Volkman ◽  
Oumar Sarr ◽  
Richard W. Steketee ◽  
Stephen F. Schaffner ◽  
Yakou Dieye ◽  
...  
Keyword(s):  
Genetic Relatedness ◽  
Imported Malaria ◽  
Travel History ◽  
Intervention Selection ◽  
Optimal Intervention ◽  
Relatedness Analysis ◽  
Molecular Barcode ◽  
Low Prevalence ◽  
Imported Infections ◽  
Local Transmission

Abstract Background Malaria elimination efforts can be undermined by imported malaria infections. Imported infections are classified based on travel history. Methods A genetic strategy was applied to better understand the contribution of imported infections and to test for local transmission in the very low prevalence region of Richard Toll, Senegal. Results Genetic relatedness analysis, based upon molecular barcode genotyping data derived from diagnostic material, provided evidence for both imported infections and ongoing local transmission in Richard Toll. Evidence for imported malaria included finding that a large proportion of Richard Toll parasites were genetically related to parasites from Thiès, Senegal, a region of moderate transmission with extensive available genotyping data. Evidence for ongoing local transmission included finding parasites of identical genotype that persisted across multiple transmission seasons as well as enrichment of highly related infections within the households of non-travellers compared to travellers. Conclusions These data indicate that, while a large number of infections may have been imported, there remains ongoing local malaria transmission in Richard Toll. These proof-of-concept findings underscore the value of genetic data to identify parasite relatedness and patterns of transmission to inform optimal intervention selection and placement.

scholarly journals Genetic evidence for imported malaria and local transmission in Richard Toll, Senegal

2020 ◽  
Author(s):  
Sarah K. Volkman ◽  
Oumar Sarr ◽  
Richard W. Steketee ◽  
Stephen F. Schaffner ◽  
Yakou Dieye ◽  
...  
Keyword(s):  
Genetic Relatedness ◽  
Imported Malaria ◽  
Travel History ◽  
Intervention Selection ◽  
Optimal Intervention ◽  
Relatedness Analysis ◽  
Molecular Barcode ◽  
Low Prevalence ◽  
Imported Infections ◽  
Local Transmission

Abstract Background: Malaria elimination efforts can be undermined by imported malaria infections. Imported infections are classified based on travel history. Methods: We applied a genetic strategy to better understand the contribution of imported infections and to test for local transmission in the very low prevalence region of Richard Toll, Senegal. Results: Genetic relatedness analysis, based upon molecular barcode genotyping data derived from diagnostic material, provided evidence for both imported infections and ongoing local transmission in Richard Toll. Evidence for imported malaria included finding that a large proportion of Richard Toll parasites were genetically related to parasites from Thiès, Senegal, a region of moderate transmission with extensive available genotyping data. Evidence for ongoing local transmission included finding parasites of identical genotype that persisted across multiple transmission seasons as well as enrichment of highly related infections within the households of non-travelers compared to travelers. Conclusions: These data indicate that, while a large number of infections may have been imported, there remains ongoing local malaria transmission in Richard Toll. These proof-of-concept findings underscore the value of genetic data to identify parasite relatedness and patterns of transmission to inform optimal intervention selection and placement.

scholarly journals Genetic evidence for imported malaria and local transmission in Richard Toll, Senegal

2020 ◽  
Author(s):  
Rachel F. Daniels ◽  
Stephen F. Schaffner ◽  
Yakou Dieye ◽  
Gnagna Dieng ◽  
Michael Hainsworth ◽  
...  
Keyword(s):  
Genetic Relatedness ◽  
Imported Malaria ◽  
Intervention Selection ◽  
Optimal Intervention ◽  
Relatedness Analysis ◽  
Molecular Barcode ◽  
Gates Foundation ◽  
Low Prevalence ◽  
Imported Infections ◽  
Local Transmission

Abstract Background: Malaria elimination efforts can be undermined by imported malaria infections. Imported infections are classified based on travel history.Methods: We applied a genetic strategy to better understand the contribution of imported infections and to test for local transmission in the very low prevalence region of Richard Toll, Senegal.Results: Genetic relatedness analysis, based upon molecular barcode genotyping data derived from diagnostic material, provided evidence for both imported infections and ongoing local transmission in Richard Toll. Evidence for imported malaria included finding that a large proportion of Richard Toll parasites were genetically related to parasites from Thiès, Senegal, a region of moderate transmission with extensive available genotyping data. Evidence for ongoing local transmission included finding parasites of identical genotype that persisted across multiple transmission seasons as well as enrichment of highly related infections within the households of non-travelers compared to travelers.Conclusions: These data indicate that, while a large number of infections may have been imported, there remains ongoing local malaria transmission in Richard Toll. These proof-of-concept findings underscore the value of genetic data to identify parasite relatedness and patterns of transmission to inform optimal intervention selection and placement. This work was supported by the Bill & Melinda Gates Foundation, Grant Number OPP1156051

scholarly journals Confirmation of the absence of local transmission and geographic assignment of imported falciparum malaria cases to China using microsatellite panel

2020 ◽  
Author(s):  
Yaobao Liu ◽  
Sofonias K Tessema ◽  
Maxwell Murphy ◽  
Sui Xu ◽  
Alanna Schwartz ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Geographic Origin ◽  
Sub Saharan Africa ◽  
High Rate ◽  
African Countries ◽  
Travel History ◽  
Assignment Method ◽  
Sub Saharan ◽  
Imported Infections ◽  
Local Transmission

Abstract Background Current methods to classify local and imported malaria infections depends primarily on patients travel history, which can have limited accuracy. Genotyping has been investigated as a complementary approach to track the spread of malaria and identify the origin of imported infections.Methods An extended panel of 26 microsatellites (16 new microsatellites) for Plasmodium falciparum was evaluated in 602 imported infections from 26 sub-Saharan African countries to the Jiangsu province of People's Republic of China. The potential of the 26 microsatellite markers to assign imported parasites to their geographic origin was assessed using a Bayesian method with MCMC (Markov Chain Monte Carlo) as implemented in the program Smoothed and Continuous Assignments (SCAT) with a modification to incorporate haploid genotype data.Results The newly designed microsatellites were polymorphic and are not in linkage disequilibrium with the existing microsatellites, supporting previous findings of high rate of recombination in sub-Saharan Africa. Consistent with epidemiology inferred from patients travel history, we found no evidence for local transmission; nearly all genetically related infections were identified in people who traveled to the same country near the same time. The smoothing assignment method assigned imported cases to their likely geographic origin with an accuracy (Angola: 59%; Nigeria: 51%; Equatorial Guinea: 40%) higher than would be achieved at random, reaching statistical significance for Angola and Equatorial Guinea.Conclusions Routine genotyping is valuable for malaria case classification and program evaluation in an elimination setting. Method for assigning geographic origin of mammals based on genetic data were adapted for malaria and showed potential for identification of the origin of imported infections.

scholarly journals The impact of mass drug administration expansion to low onchocerciasis prevalence settings in case of connected villages

2021 ◽  
Vol 15 (5) ◽  
pp. e0009011
Author(s):  
Anneke S. de Vos ◽  
Wilma A. Stolk ◽  
Luc E. Coffeng ◽  
Sake J. de Vlas
Keyword(s):  
Intermediate Host ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Human Populations ◽  
Individual Based Model ◽  
Low Prevalence ◽  
The Impact ◽  
Local Transmission

Background The existence of locations with low but stable onchocerciasis prevalence is not well understood. An often suggested yet poorly investigated explanation is that the infection spills over from neighbouring locations with higher infection densities. Methodology We adapted the stochastic individual based model ONCHOSIM to enable the simulation of multiple villages, with separate blackfly (intermediate host) and human populations, which are connected through the regular movement of the villagers and/or the flies. With this model we explore the impact of the type, direction and degree of connectedness, and of the impact of localized or full-area mass drug administration (MDA) over a range of connected village settings. Principal findings In settings with annual fly biting rates (ABR) below the threshold needed for stable local transmission, persistence of onchocerciasis prevalence can well be explained by regular human traffic and/or fly movement from locations with higher ABR. Elimination of onchocerciasis will then theoretically be reached by only implementing MDA in the higher prevalence area, although lingering infection in the low prevalence location can trigger resurgence of transmission in the total region when MDA is stopped too soon. Expanding MDA implementation to the lower ABR location can therefore shorten the duration of MDA needed. For example, when prevalence spill-over is due to human traffic, and both locations have about equal populations, then the MDA duration can be shortened by up to three years. If the lower ABR location has twice as many inhabitants, the reduction can even be up to six years, but if spill-over is due to fly movement, the expected reduction is less than a year. Conclusions/Significance Although MDA implementation might not always be necessary in locations with stable low onchocerciasis prevalence, in many circumstances it is recommended to accelerate achieving elimination in the wider area.

The genetic relatedness analysis of male sterile and their maintainer lines of onion (Allium cepa L.) by using RAPD primers

2013 ◽  
Vol 16 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Dhanya Shivnanajappa ◽  
Lakshmana Reddy Dhoranalapalli Chinnappareddy ◽  
Verre Gowda ◽  
Sreedhara Sindughatta Antharamiah ◽  
Aswath Chennareddy
Keyword(s):  
Allium Cepa ◽  
Genetic Relatedness ◽  
Male Sterile ◽  
Allium Cepa L ◽  
Relatedness Analysis

Imported Malaria to Makkah District, Saudi Arabia : Is There Any Risk of Local Transmission ?

2016 ◽  
Vol 46 (3) ◽  
pp. 461-465
Author(s):  
Mohamed El-Malky ◽  
Mohammad S. Aldosari ◽  
Ahmed Elsendiony
Keyword(s):  
Saudi Arabia ◽  
Imported Malaria ◽  
Local Transmission

scholarly journals A framework for assessing local transmission risk of imported malaria cases

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Lei Lei ◽  
Jack S. Richards ◽  
Zhi-Hong Li ◽  
Yan-Feng Gong ◽  
Shao-Zai Zhang ◽  
...  
Keyword(s):  
Imported Malaria ◽  
Transmission Risk ◽  
Local Transmission

scholarly journals Immunosuppression with Antitumour Necrosis Factor Therapy Leading to Strongyloides Hyperinfection Syndrome

2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
Muhammad Farhan Khaliq ◽  
Rayan E. Ihle ◽  
James Perry
Keyword(s):  
Respiratory Failure ◽  
Multidisciplinary Approach ◽  
Parasitic Infection ◽  
Strongyloides Stercoralis ◽  
Diagnostic Challenge ◽  
Travel History ◽  
Hyperinfection Syndrome ◽  
Factor Therapy ◽  
Low Prevalence ◽  
Necrosis Factor

Strongyloides stercoralis is an endemic parasitic infection that can remain asymptomatic for years, but it can cause death in immunosuppressed individuals. Here, we present a case of Strongyloides hyperinfection in a 75-year-old male secondary to sepsis and chronic immunosuppression due to TNF-α inhibitors. Despite aggressive treatment including broad-spectrum antibiotics and antihelminths, his respiratory failure worsened and he died after palliative extubation. S. stercoralis infection remains a diagnostic challenge. Presentation with Strongyloides is often nonspecific, and eosinophilia is absent in hyperinfection. Diagnosis can be delayed, especially in low-prevalence areas where suspicion is low. Strongyloides should be considered in the differential diagnosis in the presence of risk factors including immunosuppressive therapy, and a travel history should be carefully obtained. Patients with recurrent enterobacterial sepsis or respiratory failure with diffuse infiltrates in the setting of eosinophilia should undergo testing for Strongyloides. A multidisciplinary approach can result in earlier diagnosis and favorable outcomes.

scholarly journals Origin of imported SARS-CoV-2 strains in The Gambia identified from whole genome sequences

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0241942
Author(s):  
Abdoulie Kanteh ◽  
Jarra Manneh ◽  
Sona Jabang ◽  
Mariama A. Kujabi ◽  
Bakary Sanyang ◽  
...  
Keyword(s):  
Health Care Systems ◽  
The Gambia ◽  
Genomic Diversity ◽  
Sub Saharan Africa ◽  
Whole Genome ◽  
Travel History ◽  
Source Of Infection ◽  
Care Systems ◽  
Different Strains ◽  
Local Transmission

The SARS-CoV-2 disease, first detected in Wuhan, China, in December 2019 has become a global pandemic and is causing an unprecedented burden on health care systems and the economy globally. While the travel history of index cases may suggest the origin of infection, phylogenetic analysis of isolated strains from these cases and contacts will increase the understanding and link between local transmission and other global populations. The objective of this analysis was to provide genomic data on the first six cases of SARS-CoV-2 in The Gambia and to determine the source of infection. This ultimately provide baseline data for subsequent local transmission and contribute genomic diversity information towards local and global data. Our analysis has shown that the SARS-CoV-2 virus identified in The Gambia are of European and Asian origin and sequenced data matched patients’ travel history. In addition, we were able to show that two COVID-19 positive cases travelling in the same flight had different strains of SARS-CoV-2. Although whole genome sequencing (WGS) data is still limited in sub-Saharan Africa, this approach has proven to be a highly sensitive, specific and confirmatory tool for SARS-CoV-2 detection.

scholarly journals Comparison of epidemiological characteristics of COVID-19 patients in Vietnam

2020 ◽  
Author(s):  
Toan Ha ◽  
Gualberto Ruaño ◽  
Lewis Judy
Keyword(s):  
International Travel ◽  
Limited Data ◽  
Chi Square ◽  
Travel History ◽  
Exact Test ◽  
Overseas Travel ◽  
Chi Square Test ◽  
Available Information ◽  
Epidemiological Characteristics ◽  
Local Transmission

AbstractBackgroundThere are limited data on COVID-19 patients in Vietnam. The paper examined and compared epidemiological characteristics of COVID-19 patients in VietnamMethodThe data was obtained using publicly available information from the official website of Vietnam Ministry of Health covering a period of 01/23/2020 to 05/27/2020. T-test, Chi-square test and Fisher’s Exact test were utilized to compare characteristics of COVID-19 patients between under-treatment and discharge groups and between overseas and non-overseas travel groups.ResultsVietnam had a total of 327 cases of COVID-19 as of May 27, 2020. The median age of patients was 30 years (ranging from 3 months to 88 years). About 68% of patients (n=223) had acquired the disease from overseas while 32% were infected from local transmission. Among those infected from local transmission, 66% were women. Men were more likely than women to be infected with COVID-19 from overseas (p<0.001). Younger patients were significantly associated with international travel (p=.001). While patients in the South reported highest levels of overseas travel history (77.9%), those (100%) in the Central reported the highest level of being discharged (p<0.001). Women (54.7%) had a higher rate of discharge compared to men (45.3%) [p <0.001]. Nearly 86% have recovered and discharged from hospitals. There has been no reported fatality.ConclusionsA majority of COVID-19 cases in Vietnam were acquired overseas. A significantly higher number of women than men were infected inside the country calling for further research about gender disparities in the fight against COVID-19 in Vietnam.

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