Introduction: Tuberculosis is a major health problem in developing countries including Sudan. Screening for TB cases through Household contacts (HHCs) investigation is an appropriate strategy to interrupt transmission...Introduction: Tuberculosis is a major health problem in developing countries including Sudan. Screening for TB cases through Household contacts (HHCs) investigation is an appropriate strategy to interrupt transmission of TB. Objectives: To determine the prevalence tuberculosis infection and risk factors for tuberculosis infection among household contacts in Wadimadani locality, Central State, Sudan, between November 2015 and April 2016. Methods: An analytical cross-sectional study conducted. During study period, to confirm TB diagnosis, all suspect contacts were tested through sputum samples, tuberculin skin test or chest X-ray. Structured questionnaire was used to collect socio-demographic and environmental factors. Results: One hundred forty six patients of smear-positive pulmonary tuberculosis were included in the study, 657 household contacts were identified and screened. Forty three new TB cases were detected from household contacts, yielding a prevalence of 6.5% (95% confidence interval = 0.05, 0.09) of latent tuberculosis infection (LTBI). Two factors were significantly associated with LTBI among HHCs: duration of contact with a TB patient ≤ 4 months (P = 0.03) and the educational status (P = 0.02). Conclusion: Screening of HHCs of index case of TB will contribute in early detection and treatment of new cases, and considered as a forward step towards eliminating TB.展开更多
The recent unprecedented threat from COVID-19 and past epidemics,such as SARS,AIDS,and Ebola,has affected millions of people in multiple countries.Countries have shut their borders,and their nationals have been advise...The recent unprecedented threat from COVID-19 and past epidemics,such as SARS,AIDS,and Ebola,has affected millions of people in multiple countries.Countries have shut their borders,and their nationals have been advised to self-quarantine.The variety of responses to the pandemic has given rise to data privacy concerns.Infection prevention and control strategies as well as disease control measures,especially real-time contact tracing for COVID-19,require the identification of people exposed to COVID-19.Such tracing frameworks use mobile apps and geolocations to trace individuals.However,while the motive may be well intended,the limitations and security issues associated with using such a technology are a serious cause of concern.There are growing concerns regarding the privacy of an individual’s location and personal identifiable information(PII)being shared with governments and/or health agencies.This study presents a real-time,trust-based contact-tracing framework that operateswithout the use of an individual’sPII,location sensing,or gathering GPS logs.The focus of the proposed contact tracing framework is to ensure real-time privacy using the Bluetooth range of individuals to determine others within the range.The research validates the trust-based framework using Bluetooth as practical and privacy-aware.Using our proposed methodology,personal information,health logs,and location data will be secure and not abused.This research analyzes 100,000 tracing dataset records from 150 mobile devices to identify infected users and active users.展开更多
Tuberculosis (TB) is a chronic disease that has impacted negatively on human history. The biology of the mycobacterium tuberculosis is complicated and has affected the control as well as elimination of the disease. Ni...Tuberculosis (TB) is a chronic disease that has impacted negatively on human history. The biology of the mycobacterium tuberculosis is complicated and has affected the control as well as elimination of the disease. Nigeria is one of the countries with high incidence and prevalence of TB. The late and low case detection has been a major problem with National TB control program, caused by passive case finding strategy practiced by the country. A shift from the passive and active case search has been recommended for detection of missing cases of TB and improved program performance. The proximity of TB contact is a major determinant of disease transmission. However, maximizing early case detection and prompt treatment of notified cases is very useful in (TB) control especially in high burden countries. The tracking of TB contacts provides a good platform for early diagnosis, educating the household on TB disease and infection control as well as breaking the chain of transmission. The objective of the study is to ascertain effectiveness of contact tracing on Tuberculosis case detection. The study is a retrospective quasi experimental with quantitative arm. The study was conducted in Abia State, one of the South Eastern States of Nigeria. A pre-tested questionnaire was used for data collection and analyzed with SPSS. A total of 168 and 162 index cases of TB were recruited for both intervention and control facilities. The 168 index TB cases yielded 301 TB contacts. The result revealed 55% contact/index ratio, presumptive TB yield of 130 (43.2%) and TB yield of 68 (22.6%). The cases registered in the State increased from 336 to 417 and p value = 0.001, while presumptive TB and BCG vaccination were major predictors. The study shows that tracing contact of index TB cases is an effective and complementary method of finding undetected cases of TB.展开更多
Objective:To assess the sero-positivity rate of HIV infection among clinically suspected subjects of reproductive age group(15-49 years),biological and behavioral characteristics of the subjects gender specific variat...Objective:To assess the sero-positivity rate of HIV infection among clinically suspected subjects of reproductive age group(15-49 years),biological and behavioral characteristics of the subjects gender specific variation of sero-positivity rale,and the differentials of the sero-positivity rate for the history of blood transfusion or blood products or other organs,history of needle exposure and symptoms of morbidity.Methods:Study is based on the retrospective data of the calendar year 2005 obtained from Voluntary Counseling and Testing Centre(VCTC)(now renamed as ICTC),Department of Microbiology,I.M.S.,B.H.U..Varanasi.These cases were either referred by the consultants of different OPD'S of Sir Sunderlal Hospital or came voluntarily for knowing their HIV status.About 2-3 mL of blood samples were collected in a plain vial and tested for HIV status by strategy Ⅱ/Ⅲ as per WHO/NACO guidelines.Results:Overall sero-positivity of HIV was 15.3%(18.1%in males and 12.2%in females) which increased 6-7 folds in the age group 35-49 years as compared to 15-24 years in both the sexes.Sero-positivity rate in male migrants was 43.1%,while in female migrants it was 18.7%.The history of multiple sexual contacts was about 3 times higher in males as compared to females;predominantly it was very high in male migrants(67.7%) as compared to male non-migrants(15.8%).History of multiple sexual contacts was not uncommon in females and it was 25.0%in female migrants and 9.7%in non-migrant females.The sero-positivity rate with the history of multiple sexual contacts was 45.4%in males and 60.3%in females,while without history of multiple sexual contacts these were only 2.8%and 5.3%respectively.Sero-positive cases had on an average 3.6±1.7 various morbidity symptoms as compared to 0.7±1.1 in sero-negatives.It is to be noted that sero-positivity rate was more in those females who seemed apparently healthy compared to those presenting with some of the symptoms;vice versa,in males presenting with some symptoms HIV infection was 7 times higher than those without symptoms.Conclusions:The findings indicate a high sero-positivity among both the genders.Multiple heterosexual contacts,especially,in migrants are the main root of transmission of HIV.These are causing spread of HIV to their spouses.The multiple sexual contacts in the society,especially,among non migrant females of this region are indicating the distortion of traditions and cultures which are a serious concern and may lead to HTV infection on the rise.Awareness program to the susceptible group is the need to reduce further spread of HIV.展开更多
The pandemic of novel coronavirus disease 2019(COVID-19)has been a severe threat to public health.The policy of close contract tracing quarantine is an effective strategy in controlling the COVID-19 epidemic outbreak....The pandemic of novel coronavirus disease 2019(COVID-19)has been a severe threat to public health.The policy of close contract tracing quarantine is an effective strategy in controlling the COVID-19 epidemic outbreak.In this paper,we developed a mathematical model of the COVID-19 epidemic with confirmed case-driven contact tracing quarantine,and applied the model to evaluate the effectiveness of the policy of contact tracing and quarantine.The model is established based on the combination of the compartmental model and individual-based model simulations,which results in a closed-form delay differential equation model.The proposed model includes a novel form of quarantine functions to represent the number of quarantine individuals following the confirmed cases every day and provides analytic expressions to study the effects of changing the quarantine rate.The proposed model can be applied to epidemic dynamics during the period of community spread and when the policy of confirmed cases-driven contact tracing quarantine is efficient.We applied the model to study the effectiveness of contact tracing and quarantine.The proposed delay differential equation model can describe the average epidemic dynamics of the stochastic-individual-based model,however,it is not enough to describe the diverse response due to the stochastic effect.Based on model simulations,we found that the policy of contact tracing and quarantine can obviously reduce the epidemic size,however,may not be enough to achieve zero-infectious in a short time,a combination of close contact quarantine and social contact restriction is required to achieve zeroinfectious.Moreover,the effect of reducing epidemic size is insensitive to the period of quarantine,there are no significant changes in the epidemic dynamics when the quarantine days vary from 7 to 21 days.展开更多
Tuberculosis(TB)is on the rise in Pakistan and there could be multiple reasons including poverty,difficulty in access to TB treatment services,non-compliance with treatment,social stigma etc.According to the TB progra...Tuberculosis(TB)is on the rise in Pakistan and there could be multiple reasons including poverty,difficulty in access to TB treatment services,non-compliance with treatment,social stigma etc.According to the TB program managers,limited treatment and testing sites for tuberculosis and lack of trained human resources play a major role in compromising TB management.A major lacuna in the TB control program is the absence of active contact tracing strategy.This is essential for a disease where positive cases are known to be able to infect a further 10-15 individuals in a year.Tackling tuberculosis in Pakistan has been beleaguered by funding challenges and other systems’bottlenecks such as lack of skilled human resources and insufficient supply of medicines,despite the fact that disease burden is one of the highest in the world.Although it is a notifiable disease,active case finding,contact tracing and reporting is notoriously low throughout the country.Access to diagnostics and treatment facilities has been limited and stigma attached to the disease remains deeply entrenched among the communities.Researchers have shown that enhanced and active approaches to contact investigation effectively identifies additional patients with TB among household contacts at a relatively modest cost.USAID’s Integrated Health Systems Strengthening and Service Delivery Activity extended support to the Health Departments of Sindh and Khyber Pakhtunkhwa provinces.In collaboration with the two provincial TB programs,community based active contact tracing was conducted on 17,696 individuals,based on the index cases.Among the contacts traced,243 cases were diagnosed as drug sensitive or drug resistant TB.Awareness sessions were conducted to sensitize people on the various aspects of disease and importance of getting tested.The project also supported establishing three satellite Programmatic Management of Drug Resistant Tuberculosis(PMDT)sites for drug resistant TB treatment,enhancing the programs’diagnostic and testing capacity.展开更多
Objective To investigate the prevalence of latent tuberculosis(TB)infection(LTBI),and to identify the riskfactors in close contacts of pulmonary TB patients among non-resident population in Shanghai.Methods The study ...Objective To investigate the prevalence of latent tuberculosis(TB)infection(LTBI),and to identify the riskfactors in close contacts of pulmonary TB patients among non-resident population in Shanghai.Methods The study subjects were the close contacts of pulmonary TB patients among non-resident populations in Xuhui,Minhang展开更多
Background Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci （VRE） ...Background Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci （VRE） endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong. Methods We described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing （MLST） was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE. Results Between November 26 and December 17, 2011, 11 patients （1 exogenous case and 10 secondary cases） in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% （10/361）. There were 8 males and 3 females with a median age of 78 years （range, 40-87 years）. MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay （P 〈0.001）, a higher proportion with chronic cerebral and cardiopulmonary conditions （P=0.001）, underlying malignancies （P 〈0.001）, and presence of urinary catheter （P 〈0.001）, wound or ulcer （P 〈0.001）, and a greater proportion of these patients were receiving β-lactam/ β-1actamase inhibitors （P=0.009）, carbapenem group （P 〈0.001）, fluoroquinolones （P=0.003）, or vancomycin （P=0.001） when compared with the controls. Conclusion Extensive contact tracing and screening with a ＂search-and-confine＂ strategy was a successful tool for outbreak control in our healthcare reqion.展开更多
More than 20outbreaks of Ebola virus disease have occurred in Africa since 1976,and yet no adequate treatment is available.Hence,prevention,control measures and supportive treatment remain the only means to avoid the ...More than 20outbreaks of Ebola virus disease have occurred in Africa since 1976,and yet no adequate treatment is available.Hence,prevention,control measures and supportive treatment remain the only means to avoid the disease.Among these measures,contact tracing occupies a prominent place.In this paper,we propose a simple mathematical model that incorporates imperfect contact tracing,quarantine and hospitalization (or isolation).The control reproduction number Rc of each sub-model and for the full model are computed.Theoretically,we prove that when Tic is less than one,the corresponding model has a unique globally asymptotically stable disease-free equilibrium.Conversely, when Rc is greater than one,the disease-free equilibrium becomes unstable and a unique globally asymptotically stable endemic equilibrium arises.Furthermore,we numerically support the analytical results and assess the efficiency of different control strategies.Our main observation is that,to eradicate EVD,the combination of high contact tracing (up to 90%)and effective isolation is better than all other control measures,namely:(1) perfect contact tracing,(2)effective isolation or full hospitalization,(3)combination of medium contact tracing and medium isolation.展开更多
Background:Contact tracing is one of the strategies used to control COVID-19 pandemic.It played an important role in the beginning to identify all contacts and minimise the spread of the infection.Methods:A retrospect...Background:Contact tracing is one of the strategies used to control COVID-19 pandemic.It played an important role in the beginning to identify all contacts and minimise the spread of the infection.Methods:A retrospective chart review was carried out of contact tracing records during the one-month period,starting from the onset of the first lockdown in India.The largest wave of 372 contacts was analysed in detail to find out the association between the result of COVID-19 test and various factors(age,gender,type of contact).Results:A total of 372 contacts(214 males and 158 females)were traced and around 21%contacts were tested positive on COVID-19 RT-PCR test.Chi-square test didn’t find the significant difference between COVID-19 test result and proportions of male and female contacts,X^(2)(1)0.033,p=0.855.Female positive contacts had lower mean age compared to male positive contacts,though not statistically significant,t(75)=-1.809,p=0.0745.No difference was found in either median or mean age of contacts with respect to COVID-19 test result.Odds of tested COVID-19 positive among household contacts much higher than community contacts,OR=24.52,95%CI 12.45e48.29,p<0.05.Conclusion:No difference was noted in the rate of contracting infection with respect to age and gender of contacts.Type of contact,household or community,significantly affected the probability of becoming infected with the coronavirus.Occupation of primary case was probably responsible for large number of contacts found positive for COVID-19.展开更多
Background:In late March 2020,a“Stay Home,Stay Healthy”order was issued in Washington State in response to the COVID-19 pandemic.On May 1,a 4-phase reopening plan began.We investigated whether adjunctive prevention ...Background:In late March 2020,a“Stay Home,Stay Healthy”order was issued in Washington State in response to the COVID-19 pandemic.On May 1,a 4-phase reopening plan began.We investigated whether adjunctive prevention strategies would allow less restrictive physical distancing to avoid second epidemic waves and secure safe school reopening.Methods:We developed a mathematical model,stratifying the population by age,infection status and treatment status to project SARS-CoV-2 transmission during and after the reopening period.The model was parameterized with demographic and contact data from King County,WA and calibrated to confirmed cases,deaths and epidemic peak timing.Adjunctive prevention interventions were simulated assuming different levels of pre-COVID physical interactions(pC_PI)restored.Results:The best model fit estimated~35%pC_PI under the lockdown which prevented~17,000 deaths by May 15.Gradually restoring 75%pC_PI for all age groups between May 15-July 15 would have resulted in~350 daily deaths by early September 2020.Maintaining<45%pC_PI was required with current testing practices to ensure low levels of daily infections and deaths.Increased testing,isolation of symptomatic infections,and contact tracing permitted 60%pC_PI without significant increases in daily deaths before November and allowed opening of schools with<15 daily deaths.Inpatient antiviral treatment was predicted to reduce deaths significantly without lowering cases or hospitalizations.Conclusions:We predict that widespread testing,contact tracing and case isolation would allow relaxation of physical distancing,as well as opening of schools,without a surge in local cases and deaths.展开更多
文摘Introduction: Tuberculosis is a major health problem in developing countries including Sudan. Screening for TB cases through Household contacts (HHCs) investigation is an appropriate strategy to interrupt transmission of TB. Objectives: To determine the prevalence tuberculosis infection and risk factors for tuberculosis infection among household contacts in Wadimadani locality, Central State, Sudan, between November 2015 and April 2016. Methods: An analytical cross-sectional study conducted. During study period, to confirm TB diagnosis, all suspect contacts were tested through sputum samples, tuberculin skin test or chest X-ray. Structured questionnaire was used to collect socio-demographic and environmental factors. Results: One hundred forty six patients of smear-positive pulmonary tuberculosis were included in the study, 657 household contacts were identified and screened. Forty three new TB cases were detected from household contacts, yielding a prevalence of 6.5% (95% confidence interval = 0.05, 0.09) of latent tuberculosis infection (LTBI). Two factors were significantly associated with LTBI among HHCs: duration of contact with a TB patient ≤ 4 months (P = 0.03) and the educational status (P = 0.02). Conclusion: Screening of HHCs of index case of TB will contribute in early detection and treatment of new cases, and considered as a forward step towards eliminating TB.
基金The author would like to thank the Deanship of Scientific Research at Majmaah University for supporting this work under Project No.R-2021-131.
文摘The recent unprecedented threat from COVID-19 and past epidemics,such as SARS,AIDS,and Ebola,has affected millions of people in multiple countries.Countries have shut their borders,and their nationals have been advised to self-quarantine.The variety of responses to the pandemic has given rise to data privacy concerns.Infection prevention and control strategies as well as disease control measures,especially real-time contact tracing for COVID-19,require the identification of people exposed to COVID-19.Such tracing frameworks use mobile apps and geolocations to trace individuals.However,while the motive may be well intended,the limitations and security issues associated with using such a technology are a serious cause of concern.There are growing concerns regarding the privacy of an individual’s location and personal identifiable information(PII)being shared with governments and/or health agencies.This study presents a real-time,trust-based contact-tracing framework that operateswithout the use of an individual’sPII,location sensing,or gathering GPS logs.The focus of the proposed contact tracing framework is to ensure real-time privacy using the Bluetooth range of individuals to determine others within the range.The research validates the trust-based framework using Bluetooth as practical and privacy-aware.Using our proposed methodology,personal information,health logs,and location data will be secure and not abused.This research analyzes 100,000 tracing dataset records from 150 mobile devices to identify infected users and active users.
文摘Tuberculosis (TB) is a chronic disease that has impacted negatively on human history. The biology of the mycobacterium tuberculosis is complicated and has affected the control as well as elimination of the disease. Nigeria is one of the countries with high incidence and prevalence of TB. The late and low case detection has been a major problem with National TB control program, caused by passive case finding strategy practiced by the country. A shift from the passive and active case search has been recommended for detection of missing cases of TB and improved program performance. The proximity of TB contact is a major determinant of disease transmission. However, maximizing early case detection and prompt treatment of notified cases is very useful in (TB) control especially in high burden countries. The tracking of TB contacts provides a good platform for early diagnosis, educating the household on TB disease and infection control as well as breaking the chain of transmission. The objective of the study is to ascertain effectiveness of contact tracing on Tuberculosis case detection. The study is a retrospective quasi experimental with quantitative arm. The study was conducted in Abia State, one of the South Eastern States of Nigeria. A pre-tested questionnaire was used for data collection and analyzed with SPSS. A total of 168 and 162 index cases of TB were recruited for both intervention and control facilities. The 168 index TB cases yielded 301 TB contacts. The result revealed 55% contact/index ratio, presumptive TB yield of 130 (43.2%) and TB yield of 68 (22.6%). The cases registered in the State increased from 336 to 417 and p value = 0.001, while presumptive TB and BCG vaccination were major predictors. The study shows that tracing contact of index TB cases is an effective and complementary method of finding undetected cases of TB.
文摘Objective:To assess the sero-positivity rate of HIV infection among clinically suspected subjects of reproductive age group(15-49 years),biological and behavioral characteristics of the subjects gender specific variation of sero-positivity rale,and the differentials of the sero-positivity rate for the history of blood transfusion or blood products or other organs,history of needle exposure and symptoms of morbidity.Methods:Study is based on the retrospective data of the calendar year 2005 obtained from Voluntary Counseling and Testing Centre(VCTC)(now renamed as ICTC),Department of Microbiology,I.M.S.,B.H.U..Varanasi.These cases were either referred by the consultants of different OPD'S of Sir Sunderlal Hospital or came voluntarily for knowing their HIV status.About 2-3 mL of blood samples were collected in a plain vial and tested for HIV status by strategy Ⅱ/Ⅲ as per WHO/NACO guidelines.Results:Overall sero-positivity of HIV was 15.3%(18.1%in males and 12.2%in females) which increased 6-7 folds in the age group 35-49 years as compared to 15-24 years in both the sexes.Sero-positivity rate in male migrants was 43.1%,while in female migrants it was 18.7%.The history of multiple sexual contacts was about 3 times higher in males as compared to females;predominantly it was very high in male migrants(67.7%) as compared to male non-migrants(15.8%).History of multiple sexual contacts was not uncommon in females and it was 25.0%in female migrants and 9.7%in non-migrant females.The sero-positivity rate with the history of multiple sexual contacts was 45.4%in males and 60.3%in females,while without history of multiple sexual contacts these were only 2.8%and 5.3%respectively.Sero-positive cases had on an average 3.6±1.7 various morbidity symptoms as compared to 0.7±1.1 in sero-negatives.It is to be noted that sero-positivity rate was more in those females who seemed apparently healthy compared to those presenting with some of the symptoms;vice versa,in males presenting with some symptoms HIV infection was 7 times higher than those without symptoms.Conclusions:The findings indicate a high sero-positivity among both the genders.Multiple heterosexual contacts,especially,in migrants are the main root of transmission of HIV.These are causing spread of HIV to their spouses.The multiple sexual contacts in the society,especially,among non migrant females of this region are indicating the distortion of traditions and cultures which are a serious concern and may lead to HTV infection on the rise.Awareness program to the susceptible group is the need to reduce further spread of HIV.
基金supported by the National Natural Science Foundation of China(No.11831015).
文摘The pandemic of novel coronavirus disease 2019(COVID-19)has been a severe threat to public health.The policy of close contract tracing quarantine is an effective strategy in controlling the COVID-19 epidemic outbreak.In this paper,we developed a mathematical model of the COVID-19 epidemic with confirmed case-driven contact tracing quarantine,and applied the model to evaluate the effectiveness of the policy of contact tracing and quarantine.The model is established based on the combination of the compartmental model and individual-based model simulations,which results in a closed-form delay differential equation model.The proposed model includes a novel form of quarantine functions to represent the number of quarantine individuals following the confirmed cases every day and provides analytic expressions to study the effects of changing the quarantine rate.The proposed model can be applied to epidemic dynamics during the period of community spread and when the policy of confirmed cases-driven contact tracing quarantine is efficient.We applied the model to study the effectiveness of contact tracing and quarantine.The proposed delay differential equation model can describe the average epidemic dynamics of the stochastic-individual-based model,however,it is not enough to describe the diverse response due to the stochastic effect.Based on model simulations,we found that the policy of contact tracing and quarantine can obviously reduce the epidemic size,however,may not be enough to achieve zero-infectious in a short time,a combination of close contact quarantine and social contact restriction is required to achieve zeroinfectious.Moreover,the effect of reducing epidemic size is insensitive to the period of quarantine,there are no significant changes in the epidemic dynamics when the quarantine days vary from 7 to 21 days.
基金supported by the USAID’s Integrated Health Systems Strengthening and Service Delivery Activity,implemented by JSI Research&Training Institute under a cooperative agreement.
文摘Tuberculosis(TB)is on the rise in Pakistan and there could be multiple reasons including poverty,difficulty in access to TB treatment services,non-compliance with treatment,social stigma etc.According to the TB program managers,limited treatment and testing sites for tuberculosis and lack of trained human resources play a major role in compromising TB management.A major lacuna in the TB control program is the absence of active contact tracing strategy.This is essential for a disease where positive cases are known to be able to infect a further 10-15 individuals in a year.Tackling tuberculosis in Pakistan has been beleaguered by funding challenges and other systems’bottlenecks such as lack of skilled human resources and insufficient supply of medicines,despite the fact that disease burden is one of the highest in the world.Although it is a notifiable disease,active case finding,contact tracing and reporting is notoriously low throughout the country.Access to diagnostics and treatment facilities has been limited and stigma attached to the disease remains deeply entrenched among the communities.Researchers have shown that enhanced and active approaches to contact investigation effectively identifies additional patients with TB among household contacts at a relatively modest cost.USAID’s Integrated Health Systems Strengthening and Service Delivery Activity extended support to the Health Departments of Sindh and Khyber Pakhtunkhwa provinces.In collaboration with the two provincial TB programs,community based active contact tracing was conducted on 17,696 individuals,based on the index cases.Among the contacts traced,243 cases were diagnosed as drug sensitive or drug resistant TB.Awareness sessions were conducted to sensitize people on the various aspects of disease and importance of getting tested.The project also supported establishing three satellite Programmatic Management of Drug Resistant Tuberculosis(PMDT)sites for drug resistant TB treatment,enhancing the programs’diagnostic and testing capacity.
文摘Objective To investigate the prevalence of latent tuberculosis(TB)infection(LTBI),and to identify the riskfactors in close contacts of pulmonary TB patients among non-resident population in Shanghai.Methods The study subjects were the close contacts of pulmonary TB patients among non-resident populations in Xuhui,Minhang
文摘Background Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci （VRE） endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong. Methods We described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing （MLST） was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE. Results Between November 26 and December 17, 2011, 11 patients （1 exogenous case and 10 secondary cases） in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% （10/361）. There were 8 males and 3 females with a median age of 78 years （range, 40-87 years）. MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay （P 〈0.001）, a higher proportion with chronic cerebral and cardiopulmonary conditions （P=0.001）, underlying malignancies （P 〈0.001）, and presence of urinary catheter （P 〈0.001）, wound or ulcer （P 〈0.001）, and a greater proportion of these patients were receiving β-lactam/ β-1actamase inhibitors （P=0.009）, carbapenem group （P 〈0.001）, fluoroquinolones （P=0.003）, or vancomycin （P=0.001） when compared with the controls. Conclusion Extensive contact tracing and screening with a ＂search-and-confine＂ strategy was a successful tool for outbreak control in our healthcare reqion.
文摘More than 20outbreaks of Ebola virus disease have occurred in Africa since 1976,and yet no adequate treatment is available.Hence,prevention,control measures and supportive treatment remain the only means to avoid the disease.Among these measures,contact tracing occupies a prominent place.In this paper,we propose a simple mathematical model that incorporates imperfect contact tracing,quarantine and hospitalization (or isolation).The control reproduction number Rc of each sub-model and for the full model are computed.Theoretically,we prove that when Tic is less than one,the corresponding model has a unique globally asymptotically stable disease-free equilibrium.Conversely, when Rc is greater than one,the disease-free equilibrium becomes unstable and a unique globally asymptotically stable endemic equilibrium arises.Furthermore,we numerically support the analytical results and assess the efficiency of different control strategies.Our main observation is that,to eradicate EVD,the combination of high contact tracing (up to 90%)and effective isolation is better than all other control measures,namely:(1) perfect contact tracing,(2)effective isolation or full hospitalization,(3)combination of medium contact tracing and medium isolation.
文摘Background:Contact tracing is one of the strategies used to control COVID-19 pandemic.It played an important role in the beginning to identify all contacts and minimise the spread of the infection.Methods:A retrospective chart review was carried out of contact tracing records during the one-month period,starting from the onset of the first lockdown in India.The largest wave of 372 contacts was analysed in detail to find out the association between the result of COVID-19 test and various factors(age,gender,type of contact).Results:A total of 372 contacts(214 males and 158 females)were traced and around 21%contacts were tested positive on COVID-19 RT-PCR test.Chi-square test didn’t find the significant difference between COVID-19 test result and proportions of male and female contacts,X^(2)(1)0.033,p=0.855.Female positive contacts had lower mean age compared to male positive contacts,though not statistically significant,t(75)=-1.809,p=0.0745.No difference was found in either median or mean age of contacts with respect to COVID-19 test result.Odds of tested COVID-19 positive among household contacts much higher than community contacts,OR=24.52,95%CI 12.45e48.29,p<0.05.Conclusion:No difference was noted in the rate of contracting infection with respect to age and gender of contacts.Type of contact,household or community,significantly affected the probability of becoming infected with the coronavirus.Occupation of primary case was probably responsible for large number of contacts found positive for COVID-19.
基金This work was partially supported by National Institutes of Health(5R01AI121129-05)Centers for Disease Control and Prevention(NU38OT000297-02)Washington Research Foundation.
文摘Background:In late March 2020,a“Stay Home,Stay Healthy”order was issued in Washington State in response to the COVID-19 pandemic.On May 1,a 4-phase reopening plan began.We investigated whether adjunctive prevention strategies would allow less restrictive physical distancing to avoid second epidemic waves and secure safe school reopening.Methods:We developed a mathematical model,stratifying the population by age,infection status and treatment status to project SARS-CoV-2 transmission during and after the reopening period.The model was parameterized with demographic and contact data from King County,WA and calibrated to confirmed cases,deaths and epidemic peak timing.Adjunctive prevention interventions were simulated assuming different levels of pre-COVID physical interactions(pC_PI)restored.Results:The best model fit estimated~35%pC_PI under the lockdown which prevented~17,000 deaths by May 15.Gradually restoring 75%pC_PI for all age groups between May 15-July 15 would have resulted in~350 daily deaths by early September 2020.Maintaining<45%pC_PI was required with current testing practices to ensure low levels of daily infections and deaths.Increased testing,isolation of symptomatic infections,and contact tracing permitted 60%pC_PI without significant increases in daily deaths before November and allowed opening of schools with<15 daily deaths.Inpatient antiviral treatment was predicted to reduce deaths significantly without lowering cases or hospitalizations.Conclusions:We predict that widespread testing,contact tracing and case isolation would allow relaxation of physical distancing,as well as opening of schools,without a surge in local cases and deaths.
