scholarly journals POOLING FOR SARS-COV-2 CONTROL IN CARE INSTITUTIONS

2020 ◽  
Author(s):  
Jorge J Cabrera ◽  
Sonia Rey ◽  
Sonia Pérez ◽  
Lucía Martínez-Lamas ◽  
Olaia Cores-Calvo ◽  
...  
Keyword(s):  
Scale Up ◽  
Average Delay ◽  
Global Rate ◽  
Local Experience ◽  
Expected Performance ◽  
Pooling Strategy ◽  
Low Prevalence ◽  
Small Clusters ◽  
Very High ◽  
Special Risk

ABSTRACTWorkers and residents in Care Homes are considered at special risk for the acquisition of SARS-CoV-2 infection, due to the infectivity and high mortality rate in the case of residents, compared to other containment areas. The aims of the present study, based in our local experience, were (a) to describe SARS-CoV-2 prevalence in institutionalized people in Galicia (Spain) during the Coronavirus pandemic and (b) to evaluate the expected performance of a pooling strategy using RT-PCR for the next rounds of screening of institutionalized people.Distribution of SARS-CoV-2 infection at Care Houses was uneven. As the virus circulation global rate was low in our area, the number of people at risk of acquiring the infection continues to be very high. In this work, we have successfully demonstrated that pooling of different groups of samples at low prevalence clusters, can be done with a small average delay on quantification cycle (Cq) values. A new surveillance system with guaranteed protection is required for small clusters, previously covered with individual testing. Our proposal for Care Houses, once prevalence zero is achieved, would include successive rounds of testing using a pooling solution for transmission control preserving testing resources. Scale-up of this method may be of utility to confront larger clusters to avoid the viral circulation and keeping them operative.

scholarly journals Pooling for SARS-CoV-2 control in care institutions

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jorge Julio Cabrera Alvargonzalez ◽  
Sonia Rey Cao ◽  
Sonia Pérez Castro ◽  
Lucía Martinez Lamas ◽  
Olaia Cores Calvo ◽  
...  
Keyword(s):  
Scale Up ◽  
Care Homes ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Average Delay ◽  
Global Rate ◽  
Local Experience ◽  
Expected Performance ◽  
Pooling Strategies ◽  
Small Clusters

Abstract Background Workers and residents in Care Homes are considered at special risk for the acquisition of SARS-CoV-2 infection, due to the infectivity and high mortality rate in the case of residents, compared to other containment areas. The role of presymptomatic people in transmission has been shown to be important and the early detection of these people is critical for the control of new outbreaks. Pooling strategies have proven to preserve SARS-CoV-2 testing resources. The aims of the present study, based in our local experience, were (a) to describe SARS-CoV-2 prevalence in institutionalized people in Galicia (Spain) during the Coronavirus pandemic and (b) to evaluate the expected performance of a pooling strategy using RT-PCR for the next rounds of screening of institutionalized people. Methods A total of 25,386 Nasopharyngeal swab samples from the total of the residents and workers at Care Homes in Galicia (March to May 2020) were individually tested using RT-PCR. Prevalence and quantification cycle (Cq) value distribution of positives was calculated. Besides, 26 pools of 20 samples and 14 pools of 5 samples were tested using RT-PCR as well (1 positive/pool). Pooling proof of concept was performed in two populations with 1.7 and 2% prevalence. Results Distribution of SARS-CoV-2 infection at Care Homes was uneven (0–60%). As the virus circulation global rate was low in our area (3.32%), the number of people at risk of acquiring the infection continues to be very high. In this work, we have successfully demonstrated that pooling of different groups of samples at low prevalence clusters, can be done with a small average delay on Cq values (5 and 2.85 cycles for pools of 20 and 5 samples, respectively). Conclusions A new screening system with guaranteed protection is required for small clusters, previously covered with individual testing. Our proposal for Care Homes, once prevalence zero is achieved, would include successive rounds of testing using a pooling solution for transmission control preserving testing resources. Scale-up of this method may be of utility to confront larger clusters to avoid the viral circulation and keeping them operative.

scholarly journals Pooling for SARS-CoV-2 Control in Care Institutions

2020 ◽  
Author(s):  
Jorge J. Cabrera Alvargonzalez ◽  
Sonia Rey Cao ◽  
Sonia Pérez Castro ◽  
Lucía Martínez Lamas ◽  
Olaia Cores Calvo ◽  
...  
Keyword(s):  
Scale Up ◽  
Care Homes ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Average Delay ◽  
Global Rate ◽  
Local Experience ◽  
Expected Performance ◽  
Pooling Strategies ◽  
Small Clusters

Abstract BackgroundWorkers and residents in Care Homes are considered at special risk for the acquisition of SARS-CoV-2 infection, due to the infectivity and high mortality rate in the case of residents, compared to other containment areas. The role of presymptomatic people in transmission has been shown to be important and the early detection of these people is critical for the control of new outbreaks. Pooling strategies have proven to preserve SARS-CoV-2 testing resources.The aims of the present study, based in our local experience, were (a) to describe SARS-CoV-2 prevalence in institutionalized people in Galicia (Spain) during the Coronavirus pandemic and (b) to evaluate the expected performance of a pooling strategy using RT-PCR for the next rounds of screening of institutionalized people.MethodsA total of 25,386 Nasopharyngeal swab samples from the total of the residents and workers at Care Homes in Galicia (March to May 2020) were individually tested using RT-PCR. Prevalence and quantification cycle (Cq) value distribution of positives was calculated. Besides, 26 pools of 20 samples and 14 pools of 5 samples were tested using RT-PCR as well (1 positive/pool). Pooling proof of concept was performed in two populations with 1.7% and 2% prevalence.ResultsDistribution of SARS-CoV-2 infection at Care Homes was uneven (0-60%). As the virus circulation global rate was low in our area (3.32%), the number of people at risk of acquiring the infection continues to be very high. In this work, we have successfully demonstrated that pooling of different groups of samples at low prevalence clusters, can be done with a small average delay on Cq values (5 and 2.85 cycles for pools of 20 and 5 samples, respectively). ConclusionsA new screening system with guaranteed protection is required for small clusters, previously covered with individual testing. Our proposal for Care Homes, once prevalence zero is achieved, would include successive rounds of testing using a pooling solution for transmission control preserving testing resources. Scale-up of this method may be of utility to confront larger clusters to avoid the viral circulation and keeping them operative.

scholarly journals Pooling for SARS-CoV-2 Control in Care Institutions

2020 ◽  
Author(s):  
Jorge J. Cabrera Alvargonzalez ◽  
Sonia Rey Cao ◽  
Sonia Pérez Castro ◽  
Lucía Martínez Lamas ◽  
Olaia Cores Calvo ◽  
...  
Keyword(s):  
Scale Up ◽  
Positive Sample ◽  
Care Homes ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Average Delay ◽  
Global Rate ◽  
Local Experience ◽  
Expected Performance ◽  
Pooling Strategies

Abstract Background Workers and residents in Care Homes are considered at special risk for the acquisition of SARS-CoV-2 infection, due to the infectivity and high mortality rate in the case of residents, compared to other containment areas. The role of presymptomatic people in transmission has been shown to be important and the early detection these people is critical for the control of new outbreaks. Pooling strategies have proven to preserve SARS-CoV-2 testing resources.The aims of the present study, based in our local experience, were (a) to describe SARS-CoV-2 prevalence in institutionalized people in Galicia (Spain) during the Coronavirus pandemic and (b) to evaluate the expected performance of a pooling strategy using RT-PCR for the next rounds of screening of institutionalized people.Methods 25,386 Nasopharyngeal swab samples from the total of the residents and workers at Care Homes in Galicia (March to May 2020) were tested using RT-PCR. Prevalence and distribution of positive detection in Care Homes was calculated. Pools of 19 negative samples and one positive sample were tested using RT-PCR as well. Prevalence and distribution of positive detection in Care Homes was calculated. Results Distribution of SARS-CoV-2 infection at Care Houses was uneven. As the virus circulation global rate was low in our area, the number of people at risk of acquiring the infection continues to be very high. In this work, we have successfully demonstrated that pooling of different groups of samples at low prevalence clusters, can be done with a small average delay on quantification cycle (Cq) values. Conclusions A new surveillance system with guaranteed protection is required for small clusters, previously covered with individual testing. Our proposal for Care Houses, once prevalence zero is achieved, would include successive rounds of testing using a pooling solution for transmission control preserving testing resources. Scale-up of this method may be of utility to confront larger clusters to avoid the viral circulation and keeping them operative.

scholarly journals Frequency of HIV in Obstructive Lung Disease Patients

2018 ◽  
Vol 2 (2) ◽  
pp. 18-25
Author(s):  
Waqas Ahmed ◽  
Qudrat Ullah ◽  
Mughees Ahmed ◽  
Asif Hanif
Keyword(s):  
Lung Disease ◽  
Sample Size ◽  
Obstructive Lung Disease ◽  
Low Frequency ◽  
Smooth Muscle Contraction ◽  
Hiv Positive ◽  
Mortality And Morbidity ◽  
Causes Of Mortality ◽  
Low Prevalence ◽  
Very High

AbstractBackground: Obstructive lung disease (OLD) is one of the main causes of mortality and morbidity worldwide. Obstructive lung disease is the narrowing of bronchioles mainly due to excessive smooth muscle contraction. The objective of this study is to evaluate the Frequency of HIV in obstructive lung disease patients.Methodology: Samples were collected randomly, and study was completed in almost six months. 100 samples were taken with an informed consent taken from all the patients. EDTA and Clotted blood was collected for HIV ELISA and HIV screening.Results: In this study, 69% Males and 31%Females, 34% Smokers, 26% patients were Hypertensive, 10% patients were diabetic, 3% patients were diagnosed HIV positive by screening and ELISA.Conclusion: The frequency of HIV in obstructive lung disease patients in this research is not very high as compared to the previous researches, showing high frequency and relationship between HIV and obstructive lung disease patients. The reason behind low frequency is due to low sample size so by increasing the sample size we can get better understanding of frequency of HIV in obstructive lung disease patients. Another reason of insignificant results is low prevalence of HIV in Pakistan as compared to the previous researches in certain countries. 

scholarly journals Design and expected performance of a novel hybrid detector for very-high-energy gamma-ray astrophysics

2018 ◽  
Vol 99 ◽  
pp. 34-42 ◽  
Author(s):  
P. Assis ◽  
U. Barres de Almeida ◽  
A. Blanco ◽  
R. Conceição ◽  
B. D’Ettorre Piazzoli ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
Expected Performance ◽  
Very High Energy ◽  
Energy Gamma ◽  
Hybrid Detector ◽  
Very High

Asymptotics of pooling design performance

1999 ◽  
Vol 36 (04) ◽  
pp. 951-964
Author(s):  
J. K. Percus ◽  
O. E. Percus ◽  
W. J. Bruno ◽  
D. C. Torney
Keyword(s):  
Group Testing ◽  
Performance Criterion ◽  
Expected Number ◽  
Pooling Design ◽  
Pooling Designs ◽  
Parametric Control ◽  
Expected Performance ◽  
Qualitative Effect ◽  
Pooling Strategy ◽  
Asymptotic Forms

We analyse the expected performance of various group testing, or pooling, designs. The context is that of identifying characterized clones in a large collection of clones. Here we choose as performance criterion the expected number of unresolved ‘negative’ clones, and we aim to minimize this quantity. Technically, long inclusion–exclusion summations are encountered which, aside from being computationally demanding, give little inkling of the qualitative effect of parametric control on the pooling strategy. We show that readily-interpreted re-summation can be performed, leading to asymptotic forms and systematic corrections. We apply our results to randomized designs, illustrating how they might be implemented for approximating combinatorial formulae.

Ethnic Heterogeneity of the Factor XIII Val34Leu Polymorphism

2000 ◽  
Vol 84 (10) ◽  
pp. 601-603 ◽  
Author(s):  
Flávia Attié-Castro ◽  
Marco Zago ◽  
João Lavinha ◽  
J. Elion ◽  
L. Rodriguez-Delfin ◽  
...  
Keyword(s):  
Ethnic Groups ◽  
Factor Xiii ◽  
Pcr Amplification ◽  
Coagulation Factor ◽  
African Origin ◽  
Ethnic Heterogeneity ◽  
Very High Frequency ◽  
Exon 2 ◽  
Low Prevalence ◽  
Very High

SummaryA polymorphism in the coagulation factor XIII gene (FXIII Val34Leu) has been recently described to confer protection for arterial and venous thrombosis and to predispose to intracerebral hemorrhage. At present it is known that FXIII Val34Leu is prevalent in Caucasians, but information upon its distribution in different ethnic groups is scarce. We investigated the prevalence of FXIIIVal34Leu in 450 unrelated subjects of four ethnic groups: 97 Caucasians (Brazilians of European descent and Portuguese), 149 Blacks (Brazilians, and Africans from Cameroon, Zaire and Angola), 40 Asians (Japanese descendents) and 164 Amerindians from South America. PCR amplification of exon 2 of FXIII gene followed by MseI restriction-digestion was employed to define the genotypes. FXIIIVal34Leu was detected in 44.3% of the Caucasians, in 28.9% of the Blacks, in 2.5% of the Asians and in 51.2% of the Amerindians. These data confirm that FXIII Val34Leu is highly prevalent in Caucasians and indicate that it is rarer in populations of African origin. The very high frequency among Amerindians indicates that FXIII Val34Leu is not absent among Asians, and since it has a very low prevalence in Japanese, a heterogeneity in its distribution in Asia may be inferred. Taken together, our data showed that FXIII Val34Leu exhibits a significant ethnic heterogeneity, a finding that is relevant for studies relating this polymorphism with thrombotic and bleeding disorders.

The relative importance of bladder versus neotenic stages of Polystoma marmorati and P. umthakathi in natural frog populations in South Africa

1998 ◽  
Vol 72 (2) ◽  
pp. 117-121 ◽  
Author(s):  
L.H. Du Preez ◽  
D.J. Kok
Keyword(s):  
South Africa ◽  
Significant Contribution ◽  
Relative Importance ◽  
Natural Conditions ◽  
High Prevalence ◽  
Low Prevalence ◽  
Very High

AbstractInfection levels of Polystoma marmorati (Polystomatidae: Monogenea) in the painted reed frog, Hyperolius marmoratus, and P. umthakathi in the kloof frog, Natalobatrachus bonebergi, were studied under natural conditions. The recorded prevalence for P. marmorati was generally high in adult frogs and low in tadpoles. In the case of P. umthakathi, the opposite was found with a low prevalence in adult frogs and a very high prevalence in tadpoles. Based on these findings, the hypothesis is presented that for P. marmorati the neotenic stage does not play a determining role and the population is maintained by bladder parasites. For P. umthakathi the neotenic stage appears to be more important than the bladder parasite and the population can probably survive without any significant contribution from bladder parasites.

Asymptotics of pooling design performance

1999 ◽  
Vol 36 (4) ◽  
pp. 951-964 ◽  
Author(s):  
J. K. Percus ◽  
O. E. Percus ◽  
W. J. Bruno ◽  
D. C. Torney
Keyword(s):  
Group Testing ◽  
Performance Criterion ◽  
Expected Number ◽  
Pooling Design ◽  
Pooling Designs ◽  
Parametric Control ◽  
Expected Performance ◽  
Qualitative Effect ◽  
Pooling Strategy ◽  
Asymptotic Forms

We analyse the expected performance of various group testing, or pooling, designs. The context is that of identifying characterized clones in a large collection of clones. Here we choose as performance criterion the expected number of unresolved ‘negative’ clones, and we aim to minimize this quantity. Technically, long inclusion–exclusion summations are encountered which, aside from being computationally demanding, give little inkling of the qualitative effect of parametric control on the pooling strategy. We show that readily-interpreted re-summation can be performed, leading to asymptotic forms and systematic corrections. We apply our results to randomized designs, illustrating how they might be implemented for approximating combinatorial formulae.

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