The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Dang Dinh Thoang - One of the best experts on this subject based on the ideXlab platform.
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pandemic h1n1 virus transmission and shedding dynamics in Index Case households of a prospective vietnamese cohort
Journal of Infection, 2014Co-Authors: Pham Quang Thai, Matthijs R.a. Welkers, Vu Tien Viet Dung, Nguyen Thi Thu Yen, Tran Nhu Duong, Le Quynh Mai, Nguyen Le Khanh Hang, Le Thi Thanh, Le Nguyen Minh Hoa, Dang Dinh ThoangAbstract:Summary Objectives Influenza household transmission studies are required to guide prevention strategies but most passively recruit Index Cases that seek healthcare. We investigated A(H1N1)pdm09 transmission in a household-based cohort during 2009. Methods Health-workers visited 270 households weekly, and collected swabs from influenza-like-illness Cases. If A(H1N1)pdm09 was RT-PCR-confirmed, all household members had symptoms assessed and swabs collected daily for 10–15 days. Viral RNA was quantified and sequenced and serology performed on pre-pandemic sera. Results Index Cases were detected in 20 households containing 81 people. 98.5% lacked A(H1N1)pdm09 neutralizing antibodies in pre-pandemic sera. Eleven (18.6%, 95% CI 10.7–30.4%) of 59 contacts were infected. Virus genetic diversity within households was negligible and less than between households. Index and secondary Cases were distributed between mothers, daughters and sons, and had similar virus-RNA shedding and symptom dynamics. Fathers were rarely infected. Five secondary Cases (45%) had no apparent symptoms and three shed virus before symptoms. Secondary infection was associated with Index Case wet cough (OR 1.56, 95% CI 1.22–1.99). Conclusions In this cohort of A(H1N1)pdm09 susceptible persons, virus sequencing was capable of discriminating household from community transmission. Household transmission involved mothers and children but rarely fathers. Asymptomatic or pre-symptomatic shedding was common.
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Pandemic H1N1 virus transmission and shedding dynamics in Index Case households of a prospective Vietnamese cohort
The Journal of infection, 2014Co-Authors: Pham Quang Thai, Le Quynh Mai, Matthijs R.a. Welkers, Nguyen Le Khanh Hang, Le Thi Thanh, Vu Tien Viet Dung, Nguyen Thi Thu Yen, Tran Nhu Duong, Le Nguyen Minh Hoa, Dang Dinh ThoangAbstract:Influenza household transmission studies are required to guide prevention strategies but most passively recruit Index Cases that seek healthcare. We investigated A(H1N1)pdm09 transmission in a household-based cohort during 2009. Health-workers visited 270 households weekly, and collected swabs from influenza-like-illness Cases. If A(H1N1)pdm09 was RT-PCR-confirmed, all household members had symptoms assessed and swabs collected daily for 10-15 days. Viral RNA was quantified and sequenced and serology performed on pre-pandemic sera. Index Cases were detected in 20 households containing 81 people. 98.5% lacked A(H1N1)pdm09 neutralizing antibodies in pre-pandemic sera. Eleven (18.6%, 95% CI 10.7-30.4%) of 59 contacts were infected. Virus genetic diversity within households was negligible and less than between households. Index and secondary Cases were distributed between mothers, daughters and sons, and had similar virus-RNA shedding and symptom dynamics. Fathers were rarely infected. Five secondary Cases (45%) had no apparent symptoms and three shed virus before symptoms. Secondary infection was associated with Index Case wet cough (OR 1.56, 95% CI 1.22-1.99). In this cohort of A(H1N1)pdm09 susceptible persons, virus sequencing was capable of discriminating household from community transmission. Household transmission involved mothers and children but rarely fathers. Asymptomatic or pre-symptomatic shedding was common. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.
Sita Naik - One of the best experts on this subject based on the ideXlab platform.
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A serological study of intrafamilial spread from patients with sporadic hepatitis E virus infection.
Journal of Viral Hepatitis, 2003Co-Authors: Salma K. Somani, Sita Naik, Sachin Srivastava, Rakesh AggarwalAbstract:Summary. Intrafamilial transmission is rare in epidemic hepatitis E; its frequency in sporadic hepatitis E is not known. We followed up 86 household contacts (age range 4–75 years, mean ± SD 32.4 ± 15.8; 49 males), who were family members of patients with acute sporadic hepatitis E. Of the 86 contacts, 68 (79%) tested negative for IgG anti-hepatitis E virus antibodies. Four (4.7%) had IgM anti-hepatitis E virus antibodies at the time of diagnosis of hepatitis E in the Index Case; two of these contacts possibly had hepatitis E virus infection acquired simultaneously with that in the Index Case, and two could have had intrafamilial transmission. None developed serological evidence of hepatitis E virus infection over a period of 49 ± 18 days after the diagnosis of Index Case, although a majority lacked IgG antibodies to hepatitis E virus and were likely to be susceptible. This suggests that person-to-person transmission is uncommon in sporadic hepatitis E.
Pham Quang Thai - One of the best experts on this subject based on the ideXlab platform.
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pandemic h1n1 virus transmission and shedding dynamics in Index Case households of a prospective vietnamese cohort
Journal of Infection, 2014Co-Authors: Pham Quang Thai, Matthijs R.a. Welkers, Vu Tien Viet Dung, Nguyen Thi Thu Yen, Tran Nhu Duong, Le Quynh Mai, Nguyen Le Khanh Hang, Le Thi Thanh, Le Nguyen Minh Hoa, Dang Dinh ThoangAbstract:Summary Objectives Influenza household transmission studies are required to guide prevention strategies but most passively recruit Index Cases that seek healthcare. We investigated A(H1N1)pdm09 transmission in a household-based cohort during 2009. Methods Health-workers visited 270 households weekly, and collected swabs from influenza-like-illness Cases. If A(H1N1)pdm09 was RT-PCR-confirmed, all household members had symptoms assessed and swabs collected daily for 10–15 days. Viral RNA was quantified and sequenced and serology performed on pre-pandemic sera. Results Index Cases were detected in 20 households containing 81 people. 98.5% lacked A(H1N1)pdm09 neutralizing antibodies in pre-pandemic sera. Eleven (18.6%, 95% CI 10.7–30.4%) of 59 contacts were infected. Virus genetic diversity within households was negligible and less than between households. Index and secondary Cases were distributed between mothers, daughters and sons, and had similar virus-RNA shedding and symptom dynamics. Fathers were rarely infected. Five secondary Cases (45%) had no apparent symptoms and three shed virus before symptoms. Secondary infection was associated with Index Case wet cough (OR 1.56, 95% CI 1.22–1.99). Conclusions In this cohort of A(H1N1)pdm09 susceptible persons, virus sequencing was capable of discriminating household from community transmission. Household transmission involved mothers and children but rarely fathers. Asymptomatic or pre-symptomatic shedding was common.
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Pandemic H1N1 virus transmission and shedding dynamics in Index Case households of a prospective Vietnamese cohort
The Journal of infection, 2014Co-Authors: Pham Quang Thai, Le Quynh Mai, Matthijs R.a. Welkers, Nguyen Le Khanh Hang, Le Thi Thanh, Vu Tien Viet Dung, Nguyen Thi Thu Yen, Tran Nhu Duong, Le Nguyen Minh Hoa, Dang Dinh ThoangAbstract:Influenza household transmission studies are required to guide prevention strategies but most passively recruit Index Cases that seek healthcare. We investigated A(H1N1)pdm09 transmission in a household-based cohort during 2009. Health-workers visited 270 households weekly, and collected swabs from influenza-like-illness Cases. If A(H1N1)pdm09 was RT-PCR-confirmed, all household members had symptoms assessed and swabs collected daily for 10-15 days. Viral RNA was quantified and sequenced and serology performed on pre-pandemic sera. Index Cases were detected in 20 households containing 81 people. 98.5% lacked A(H1N1)pdm09 neutralizing antibodies in pre-pandemic sera. Eleven (18.6%, 95% CI 10.7-30.4%) of 59 contacts were infected. Virus genetic diversity within households was negligible and less than between households. Index and secondary Cases were distributed between mothers, daughters and sons, and had similar virus-RNA shedding and symptom dynamics. Fathers were rarely infected. Five secondary Cases (45%) had no apparent symptoms and three shed virus before symptoms. Secondary infection was associated with Index Case wet cough (OR 1.56, 95% CI 1.22-1.99). In this cohort of A(H1N1)pdm09 susceptible persons, virus sequencing was capable of discriminating household from community transmission. Household transmission involved mothers and children but rarely fathers. Asymptomatic or pre-symptomatic shedding was common. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.
Xiaofei Zhou - One of the best experts on this subject based on the ideXlab platform.
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prolonged intracisternal papaverine toxicity Index Case description and proposed mechanism of action
World Neurosurgery, 2018Co-Authors: Xiaofei Zhou, Vilakshan Alambyan, Thomas A Ostergard, Jonathan Pace, Maryo Kohen, Sunil Manjila, Ciro RamosestebanezAbstract:Background Intracisternal papaverine (iPPV) is a vasodilator used for prophylaxis of intraoperative vasospasm during aneurysmal clipping. Postoperative side effects of iPPV include transient cranial nerve palsies, most commonly mydriasis owing to oculomotor nerve involvement, with rapid resolution. Methods We critically reviewed current literature on the adverse effects of iPPV in aneurysmal surgery with a focus on oculomotor nerve involvement. We also present the Index Case of prolonged bilateral mydriasis secondary to iPPV irrigation toxicity and its putative underlying mechanism. Results Papaverine toxicity occurs in the setting of its antimuscarinic action and blood–cerebrospinal fluid and blood-brain barrier compromise owing to acute subarachnoid hemorrhage and direct effect of papaverine. Our patient also experienced severe vasospasm and a minor stroke, both contributing to further blood-brain barrier disruption, and relatively acidic pH of the subarachnoid hemorrhage milieu. Conclusions We propose that these factors perpetuate phase dynamics of papaverine crystals and facilitate a sustained slow release of papaverine within the cisternal system. Were it indicated, 0.3% iPPV would reasonably diminish the risk for neurotoxicity.
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Prolonged Intracisternal Papaverine Toxicity: Index Case Description and Proposed Mechanism of Action.
World neurosurgery, 2017Co-Authors: Xiaofei Zhou, Vilakshan Alambyan, Thomas A Ostergard, Jonathan Pace, Maryo Kohen, Sunil Manjila, Ciro Ramos-estebanezAbstract:Intracisternal papaverine (iPPV) is a vasodilator used for prophylaxis of intraoperative vasospasm during aneurysmal clipping. Postoperative side effects of iPPV include transient cranial nerve palsies, most commonly mydriasis owing to oculomotor nerve involvement, with rapid resolution. We critically reviewed current literature on the adverse effects of iPPV in aneurysmal surgery with a focus on oculomotor nerve involvement. We also present the Index Case of prolonged bilateral mydriasis secondary to iPPV irrigation toxicity and its putative underlying mechanism. Papaverine toxicity occurs in the setting of its antimuscarinic action and blood-cerebrospinal fluid and blood-brain barrier compromise owing to acute subarachnoid hemorrhage and direct effect of papaverine. Our patient also experienced severe vasospasm and a minor stroke, both contributing to further blood-brain barrier disruption, and relatively acidic pH of the subarachnoid hemorrhage milieu. We propose that these factors perpetuate phase dynamics of papaverine crystals and facilitate a sustained slow release of papaverine within the cisternal system. Were it indicated, 0.3% iPPV would reasonably diminish the risk for neurotoxicity. Copyright © 2017 Elsevier Inc. All rights reserved.
Nicola Low - One of the best experts on this subject based on the ideXlab platform.
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differences in secondary attack rates based on symptom status of Index Case s a living systematic review
medRxiv, 2021Co-Authors: Xueting Qiu, Nicola Low, Ali Ihsan Nergiz, Alberto Enrico Maraolo, Isaac I Bogoch, Muge CevikAbstract:Background Reports suggest that asymptomatic individuals (those with no symptoms at all throughout infection) with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are infectious, but the extent of transmission based on symptom status requires further study. Purpose This living review aims to critically appraise available data about secondary attack rates from people with asymptomatic, pre-symptomatic and symptomatic SARS-CoV-2 infection. Data sources Medline, EMBASE, China Academic Journals full-text database (CNKI), and pre-print servers were searched from 30 December 2019 to 3 July 2020 using relevant MESH terms. Study selection Studies that report on contact tracing of Index Cases with SARS-CoV-2 infection in either English or Chinese were included. Data extraction Two authors independently extracted data and assessed study quality and risk of bias. We calculated the secondary attack rate as the number of contacts with SARS-CoV-2, divided by the number of contacts tested. Data synthesis Of 927 studies identified, 80 were included. Summary secondary attack rate estimates were 1% (95% CI: 0%-2%) with a prediction interval of 0-10% for asymptomatic Index Cases in 10 studies, 7% (95% CI: 3%-11%) with a prediction interval of 1- 40% for pre-symptomatic Cases in 11 studies and 6% (95% CI: 5%-8%) with a prediction interval of 5- 38% for symptomatic Index Cases in 40 studies. The highest secondary attack rates were found in contacts who lived in the same household as the Index Case. Other activities associated with transmission were group activities such as sharing meals or playing board games with the Index Case, regardless of the disease status of the Index Case. Limitations We excluded some studies because the Index Case or number of contacts were unclear. Conclusion Asymptomatic patients can transmit SARS-CoV-2 to others, but our findings indicate that such individuals are responsible for fewer secondary infections than people with symptoms. Systematic review registration PROSPERO CRD42020188168
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ebola virus disease outbreak in nigeria transmission dynamics and rapid control
Epidemics, 2015Co-Authors: Christian L Althaus, Nicola Low, Emmanuel Musa, Faisal Shuaib, Sandro GsteigerAbstract:International air travel has already spread Ebola virus disease (EVD) to major cities as part of the unprecedented epidemic that started in Guinea in December 2013. An infected airline passenger arrived in Nigeria on July 20, 2014 and caused an outbreak in Lagos and then Port Harcourt. After a total of 20 reported Cases, including 8 deaths, Nigeria was declared EVD free on October 20, 2014. We quantified the impact of early control measures in preventing further spread of EVD in Nigeria and calculated the risk that a single undetected Case will cause a new outbreak. We fitted an EVD transmission model to data from the outbreak in Nigeria and estimated the reproduction number of the Index Case at 9.0 (95% confidence interval [CI]: 5.2-15.6). We also found that the net reproduction number fell below unity 15 days (95% CI: 11-21 days) after the arrival of the Index Case. Hence, our study illustrates the time window for successful containment of EVD outbreaks caused by infected air travelers.
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variation in partner notification outcomes for chlamydia in uk genitourinary medicine clinics multilevel study
Sexually Transmitted Infections, 2011Co-Authors: Sereina A Herzog, Chris Carne, Hugo Mcclean, Nicola LowAbstract:Objectives To compare different ways of measuring partner notification (PN) outcomes with published audit standards, examine variability between clinics and examine factors contributing to variation in PN outcomes in genitourinary medicine (GUM) clinics in the UK. Methods Reanalysis of the 2007 BASHH national chlamydia audit. The primary outcome was the number of partners per Index Case tested for chlamydia, as verified by a healthcare worker or, if missing, reported by the patient. Control charts were used to examine variation between clinics considering missing values as zero or excluding missing values. Hierarchical logistic regression was used to investigate factors contributing to variation in outcomes. Results Data from 4616 individuals in 169 genitourinary medicine clinics were analysed. There was no information about the primary outcome in 41% of records. The mean number of partners tested for chlamydia ranged from 0 to 1.5 per Index Case per clinic. The median across all clinics was 0.47 when missing values were assumed to be zero and 0.92 per Index Case when missing values were excluded. Men who have sex with men were less likely than heterosexual men and patients with symptoms (4-week look-back period) were less likely than asymptomatic patients (6-month look-back) to report having one or more partners tested for chlamydia. There was no association between the primary outcome and the type of the health professional giving the PN advice. Conclusions The completeness of PN outcomes recorded in clinical notes needs to improve. Further research is needed to identify auditable measures that are associated with successful PN that prevents repeated chlamydia in Index Cases.
