scholarly journals Infectious Reactivation of Cytomegalovirus Explaining Age- and Sex-Specific Patterns of Seroprevalence

2017 ◽  
Author(s):  
Michiel van Boven ◽  
Jan van de Kassteele ◽  
Marjolein J. Korndewal ◽  
Christiaan H. van Dorp ◽  
Mirjam Kretzschmar ◽  
...  
Keyword(s):  
Older Women ◽  
Primary Infection ◽  
Transmission Dynamics ◽  
Specific Antibody Response ◽  
Response Data ◽  
Quantitative Estimates ◽  
Main Driver ◽  
Transmission Models ◽  
Infection Episode ◽  
Age And Sex

AbstractHuman cytomegalovirus is a herpes virus with poorly understood transmission dynamics. We here provide quantitative estimates of the transmissibility of primary infection, reactivation, and re-infection using age-and sex-specific antibody response data. The data are optimally described by three distributions of antibody measurements, i.e. uninfected, infected, and infected after reactivation/re-infection. Estimates of seroprevalence increase gradually with age, such that at 80 years 73% (95%CrI: 64%-78%) of females and 62% (95%CrI: 55%-68%) of males is infected, while 57% (95%CrI: 47%-67%) of females and 37% (95%CrI: 28%-46%) of males has experienced a reactivation or re-infection episode. Merging the statistical analyses with transmission models, we find that infectious reactivation is key to provide a good fit fit to the data. Estimated reactivation rates increase from low values in children to 2%-6% per year older women. The results advance a hypothesis in which adult-to-adult transmission after infectious reactivation is the main driver of infection.

scholarly journals The effects of flooding and weather conditions on leptospirosis transmission in Thailand

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sudarat Chadsuthi ◽  
Karine Chalvet-Monfray ◽  
Anuwat Wiratsudakul ◽  
Charin Modchang
Keyword(s):  
Sensitivity Analysis ◽  
Public Education ◽  
Mathematical Models ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Weather Conditions ◽  
Transmission Dynamics ◽  
Multiplication Rate ◽  
High Degree ◽  
Transmission Models

AbstractThe epidemic of leptospirosis in humans occurs annually in Thailand. In this study, we have developed mathematical models to investigate transmission dynamics between humans, animals, and a contaminated environment. We compared different leptospire transmission models involving flooding and weather conditions, shedding and multiplication rate in a contaminated environment. We found that the model in which the transmission rate depends on both flooding and temperature, best-fits the reported human data on leptospirosis in Thailand. Our results indicate that flooding strongly contributes to disease transmission, where a high degree of flooding leads to a higher number of infected individuals. Sensitivity analysis showed that the transmission rate of leptospires from a contaminated environment was the most important parameter for the total number of human cases. Our results suggest that public education should target people who work in contaminated environments to prevent Leptospira infections.

scholarly journals Nematospiroides dubius in the jird, Meriones unguiculatus: factors affecting the course of a primary infection

1982 ◽  
Vol 56 (4) ◽  
pp. 329-338 ◽  
Author(s):  
John Hannah ◽  
Jerzy M. Behnke
Keyword(s):  
Primary Infection ◽  
Meriones Unguiculatus ◽  
Baseline Data ◽  
Factors Affecting ◽  
Low Level ◽  
Susceptibility To Infection ◽  
Infective Larvae ◽  
Nematospiroides Dubius ◽  
Future Work ◽  
Age And Sex

ABSTRACTThis project investigated the influence of the age and sex of the host and the level of infection with Nematospiroides dubius on the establishment and duration of a primary infection in the jird. It was found that 30 to 35% fewer worms matured in jirds than in mice and that this proportion was unaffected by the level of infection or by the sex of the host. In contrast the age of the jird was found to be critically important in determining the number of adult worms recovered 14 days after infection. Thus, maximum susceptibility to infection was observed when jirds were 18 to 22 days old. In older jirds susceptibility declined until 30 days after birth and thereafter, when approximately 70% of the infective larvae matured (relative to the number of worms maturing in mice).The duration of a primary infection in jirds was similar in both sexes but was influenced by the level of infection and by the age of the host at infection. Heavier infections (500 larvae) lasted about 10 days longer than low level infections, and expulsion of the parasite occurred even when the host was infected with only five larvae. The duration of a primary infection was markedly prolonged in neonatal jirds, faecal egg counts remaining positive for 54 to 56 days after infection of 12-day-old jirds.These results supply some further baseline data for future work on the biology of N. dubius in the jird and they provide support for the involvement of immunological processes in the termination of primary infections of this parasite in mature jirds.

scholarly journals Demographic patterns of human antibody levels to Simulium damnosum s.l. saliva in onchocerciasis-endemic areas: An indicator of exposure to vector bites

2022 ◽  
Vol 16 (1) ◽  
pp. e0010108
Author(s):  
Laura Willen ◽  
Philip Milton ◽  
Jonathan I. D. Hamley ◽  
Martin Walker ◽  
Mike Y. Osei-Atweneboana ◽  
...  
Keyword(s):  
Linear Models ◽  
Cumulative Exposure ◽  
Human Antibody ◽  
Adult Males ◽  
Simulium Damnosum ◽  
Endemic Areas ◽  
Demographic Patterns ◽  
Antibody Levels ◽  
Transmission Models ◽  
Age And Sex

Background In onchocerciasis endemic areas in Africa, heterogenous biting rates by blackfly vectors on humans are assumed to partially explain age- and sex-dependent infection patterns with Onchocerca volvulus. To underpin these assumptions and further improve predictions made by onchocerciasis transmission models, demographic patterns in antibody responses to salivary antigens of Simulium damnosum s.l. are evaluated as a measure of blackfly exposure. Methodology/Principal findings Recently developed IgG and IgM anti-saliva immunoassays for S. damnosum s.l. were applied to blood samples collected from residents in four onchocerciasis endemic villages in Ghana. Demographic patterns in antibody levels according to village, sex and age were explored by fitting generalized linear models. Antibody levels varied between villages but showed consistent patterns with age and sex. Both IgG and IgM responses declined with increasing age. IgG responses were generally lower in males than in females and exhibited a steeper decline in adult males than in adult females. No sex-specific difference was observed in IgM responses. Conclusions/Significance The decline in age-specific antibody patterns suggested development of immunotolerance or desensitization to blackfly saliva antigen in response to persistent exposure. The variation between sexes, and between adults and youngsters may reflect differences in behaviour influencing cumulative exposure. These measures of antibody acquisition and decay could be incorporated into onchocerciasis transmission models towards informing onchocerciasis control, elimination, and surveillance.

scholarly journals Transmission of SARS-CoV-2 associated with cruise ship travel: protocol for a systematic review (Version 1)

2021 ◽  
Author(s):  
Elena Cecilia Rosca ◽  
Carl Heneghan ◽  
Elizabeth A Spencer ◽  
Jon Brassey ◽  
Annette Pluddemann ◽  
...  
Keyword(s):  
Reference Lists ◽  
Viral Infections ◽  
Meta Analysis ◽  
Policy Implications ◽  
Cruise Ship ◽  
Research Gaps ◽  
Cruise Ships ◽  
Quantitative Estimates ◽  
Transmission Models

Background: Maritime and river travel, including cruise ships, have been implicated with spreading viruses through infected passengers and crew. Given the novelty of the SARS-CoV-2 infection, early cruise ship travel transmission models of spread are based on what is known of the dynamics of other respiratory viral infections. Our objective is to provide a rapid summary and evaluation of relevant data on SARS-CoV-2 transmission aboard cruise ships, report policy implications, and highlight research gaps requiring attention. Methods: We will search LitCovid, medRxiv, Google Scholar, and the WHO Covid-19 database using COVID-19, SARS-CoV-2, transmission, and cruise ship appropriate synonyms. We will also search the reference lists of included studies for additional relevant studies. We will include studies reporting onboard SARS-CoV-2 transmission from passengers and/or crew to passengers and/or crew. We will consider any potential transmission mode. We will assess study quality based on five criteria and report important findings. The outcome will consist of the onboard cruise ships transmission of SARS-CoV-2. We will provide a narrative summary of the data and report the outcomes, including quantitative estimates where feasible and relevant. Where possible, compatible datasets may be pooled for meta-analysis. Expected results: We will present the evidence in three distinct packages: study description, methodological quality assessment and data extracted. We will summarize the evidence and will draw conclusions as to the quality of the evidence.

Implications on older women of age- and sex-related differences in activation patterns of shoulder muscles: A cross-sectional study

2018 ◽  
Vol 31 (6) ◽  
pp. 492-512
Author(s):  
Cristina Lirio-Romero ◽  
Christoph Anders ◽  
Pedro De La Villa-Polo ◽  
María Torres-Lacomba
Keyword(s):  
Older Women ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Activation Patterns ◽  
Shoulder Muscles ◽  
Age And Sex

scholarly journals The World Health Organization 2030 goals for Taenia solium: Insights and perspectives from transmission dynamics modelling

2019 ◽  
Vol 3 ◽  
pp. 1546 ◽  
Author(s):  
Keyword(s):  
World Health Organization ◽  
Taenia Solium ◽  
Sub Saharan Africa ◽  
Transmission Dynamics ◽  
World Health ◽  
Sustainable Solutions ◽  
The World ◽  
Health Organization ◽  
The Impact ◽  
Transmission Models

Taenia solium (TS), responsible for porcine cysticercosis, human taeniasis and (neuro)cysticercosis, was included in the World Health Organization neglected tropical disease (NTD) roadmap published in 2012. Targets set in this roadmap have not been met, but T. solium has been included in the consultation process for the new 2030 goals proposed for priority NTDs. Taenia solium transmission dynamics models can contribute to this process. A recent review has compared existing T. solium transmission models, identifying their similarities and differences in structure, parameterization and modelled intervention approaches. While a formal model comparison to investigate the impact of interventions is yet to be conducted, the models agree on the importance of coverage for intervention effectiveness and on the fact that human- and pig-focused interventions can be optimally combined. One of these models, cystiSim, an individual-based, stochastic model has been used to assess field-applicable interventions, some currently under evaluation in on-going trials in Zambia. The EPICYST, population-based, deterministic model has highlighted, based on simulating a generic sub-Saharan Africa setting, the higher efficacy (measured as the percentage of human cysticercosis cases prevented) of biomedical interventions (human and pig treatment and pig vaccination) compared to improved husbandry, sanitation, and meat inspection. Important questions remain regarding which strategies and combinations thereof provide sustainable solutions for severely resource-constrained endemic settings. Defining realistic timeframes to achieve feasible targets, and establishing suitable measures of effectiveness for these targets that can be quantified with current monitoring and evaluation tools, are current major barriers to identifying validated strategies. Taenia solium transmission models can support setting achievable 2030 goals; however, the refinement of these models is first required. Incorporating socio-economic elements, improved understanding of underlying biological processes, and consideration of spatial dynamics are key knowledge gaps that need addressing to support model development.

scholarly journals Cross-sectional centiles of blood pressure by age and sex: a four-hospital database retrospective observational analysis

BMJ Open ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. e033618
Author(s):  
David Wong ◽  
Stephen Gerry ◽  
Farah Shamout ◽  
David A Clifton ◽  
Marco A F Pimentel ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Older Women ◽  
Vital Signs ◽  
National Guidelines ◽  
Database Analysis ◽  
Cross Sectional ◽  
Younger Women ◽  
Hospital Database ◽  
Hospitalised Patients ◽  
Age And Sex

ObjectivesNational guidelines for identifying physiological deterioration and sepsis in hospitals depend on thresholds for blood pressure that do not account for age or sex. In populations outside hospital, differences in blood pressure are known to occur with both variables. Whether these differences remain in the hospitalised population is unknown. This database analysis study aims to generate representative centiles to quantify variations in blood pressure by age and sex in hospitalised patients.DesignRetrospective cross-sectional observational database analysis.SettingFour near-sea-level hospitals between April 2015 and April 2017Participants75 342 adult patients who were admitted to the hospitals and had at least one set of documented vital sign observations within 24 hours before discharge were eligible for inclusion. Patients were excluded if they died in hospital, had no vital signs 24 hours prior to discharge, were readmitted within 7 days of discharge, had missing age or sex or had no blood pressure recorded.ResultsSystolic blood pressure (SBP) for hospitalised patients increases with age for both sexes. Median SBP increases from 122 (CI: 121.1 to 122.1) mm Hg to 132 (CI: 130.9 to 132.2) mm Hg in men, and 114 (CI: 113.1 to 114.4) mm Hg to 135 (CI: 134.5 to 136.2) mm Hg in women, between the ages of 20 and 90 years. Diastolic blood pressure peaked around 50 years for men 76 (CI: 75.5 to 75.9) mm Hg and women 69 (CI: 69.0 to 69.4) mm Hg. The blood pressure criterion for sepsis, systolic <100 mm Hg, was met by 2.3% of younger (20–30 years) men and 3.5% of older men (81–90 years). In comparison, the criterion was met by 9.7% of younger women and 2.6% of older women.ConclusionWe have quantified variations in blood pressure by age and sex in hospitalised patients that have implications for recognition of deterioration. Nearly 10% of younger women met the blood pressure criterion for sepsis at hospital discharge.

scholarly journals The World Health Organization 2030 goals for Taenia solium: Insights and perspectives from transmission dynamics modelling

2019 ◽  
Vol 3 ◽  
pp. 1546 ◽  
Author(s):  
Keyword(s):  
World Health Organization ◽  
Taenia Solium ◽  
Sub Saharan Africa ◽  
Transmission Dynamics ◽  
World Health ◽  
Sustainable Solutions ◽  
The World ◽  
Health Organization ◽  
The Impact ◽  
Transmission Models

Taenia solium (TS), responsible for porcine cysticercosis, human taeniasis and (neuro)cysticercosis, was included in the World Health Organization neglected tropical disease (NTD) roadmap published in 2012. Targets set in this roadmap have not been met, but T. solium has been included in the consultation process for the new 2030 goals proposed for priority NTDs. Taenia solium transmission dynamics models can contribute to this process. A recent review has compared existing T. solium transmission models, identifying their similarities and differences in structure, parameterization and modelled intervention approaches. While a formal model comparison to investigate the impact of interventions is yet to be conducted, the models agree on the importance of coverage for intervention effectiveness and on the fact that human- and pig-focused interventions can be optimally combined. One of these models, cystiSim, an individual-based, stochastic model has been used to assess field-applicable interventions, some currently under evaluation in on-going trials in Zambia. The EPICYST, population-based, deterministic model has highlighted, based on simulating a generic sub-Saharan Africa setting, the higher efficacy (measured as the percentage of human cysticercosis cases prevented) of biomedical interventions (human and pig treatment and pig vaccination) compared to improved husbandry, sanitation, and meat inspection. Important questions remain regarding which strategies and combinations thereof provide sustainable solutions for severely resource-constrained endemic settings. Defining realistic timeframes to achieve feasible targets, and establishing suitable measures of effectiveness for these targets that can be quantified with current monitoring and evaluation tools, are current major barriers to identifying validated strategies. Taenia solium transmission models can support setting achievable 2030 goals; however, the refinement of these models is first required. Incorporating socio-economic elements, improved understanding of underlying biological processes, and consideration of spatial dynamics are key knowledge gaps that need addressing to support model development.

Sign in / Sign up

Export Citation Format

Share Document