Transmission heterogeneities, kinetics, and controllability of SARS-CoV-2

Science ◽

10.1126/science.abe2424 ◽

2020 ◽

pp. eabe2424 ◽

Cited By ~ 8

Author(s):

Kaiyuan Sun ◽

Wei Wang ◽

Lidong Gao ◽

Yan Wang ◽

Kaiwei Luo ◽

...

Keyword(s):

Social Interactions ◽

Population Level ◽

Transmission Risk ◽

Contact Tracing ◽

Symptom Presentation ◽

Secondary Infections ◽

The Family ◽

Infectious Disease Dynamics ◽

Kinetics Of

A long-standing question in infectious disease dynamics concerns the role of transmission heterogeneities, driven by demography, behavior and interventions. Based on detailed patient and contact tracing data in Hunan, China we find 80% of secondary infections traced back to 15% of SARS-CoV-2 primary infections, indicating substantial transmission heterogeneities. Transmission risk scales positively with the duration of exposure and the closeness of social interactions and is modulated by demographic and clinical factors. The lockdown period increases transmission risk in the family and households, while isolation and quarantine reduce risks across all types of contacts. The reconstructed infectiousness profile of a typical SARS-CoV-2 patient peaks just before symptom presentation. Modeling indicates SARS-CoV-2 control requires the synergistic efforts of case isolation, contact quarantine, and population-level interventions, owing to the specific transmission kinetics of this virus.

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Transmission heterogeneities, kinetics, and controllability of SARS-CoV-2

10.1101/2020.08.09.20171132 ◽

2020 ◽

Cited By ~ 1

Author(s):

Kaiyuan Sun ◽

Wei Wang ◽

Lidong Gao ◽

Yan Wang ◽

Kaiwei Luo ◽

...

Keyword(s):

Population Level ◽

Transmission Risk ◽

Contact Tracing ◽

Symptom Presentation ◽

Health Measures ◽

Secondary Infections ◽

The Family ◽

Infectious Disease Dynamics ◽

Kinetics Of

AbstractA long-standing question in infectious disease dynamics concerns the role of transmission heterogeneities, driven by demography, behavior and interventions. Based on detailed patient and contact tracing data in Hunan, China we find 80% of secondary infections traced back to 15% of SARS-CoV-2 primary infections, indicating substantial transmission heterogeneities. Transmission risk scales positively with the duration of exposure and the closeness of social interactions and is modulated by demographic and clinical factors. The lockdown period increases transmission risk in the family and households, while isolation and quarantine reduce risks across all types of contacts. The reconstructed infectiousness profile of a typical SARS-CoV-2 patient peaks just before symptom presentation. Modeling indicates SARS-CoV-2 control requires the synergistic efforts of case isolation, contact quarantine, and population-level interventions, owing to the specific transmission kinetics of this virus.One Sentence SummaryPublic health measures to control SARS-CoV-2 could be designed to block the specific transmission characteristics of the virus.

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Contribution of cysteine residue to the properties of Listeria monocytogenes listeriolysin O

Canadian Journal of Microbiology ◽

10.1139/w09-070 ◽

2009 ◽

Vol 55 (10) ◽

pp. 1153-1159 ◽

Cited By ~ 6

Author(s):

Radosław Stachowiak ◽

Jarosław Wiśniewski ◽

Olga Osińska ◽

Jacek Bielecki

Keyword(s):

Listeria Monocytogenes ◽

Hemolytic Activity ◽

Cysteine Residue ◽

Listeriolysin O ◽

Wild Type ◽

Gram Positive Bacteria ◽

Culture Model ◽

The Family ◽

Kinetics Of

Listeriolysin (LLO) is the key virulence factor critical for Listeria monocytogenes pathogenesis. Listerial cytolysin belongs to the family of cholesterol-dependent cytolysins (CDCs), a group of pore-forming toxins produced by related gram-positive bacteria. Most CDCs contain a cysteine residue in the conserved undecapeptide — a sequence that is highly preserved among this group of proteins. Substitutions of cysteine do not always lead to loss of hemolytic activity, questioning the purpose of such strong conservation of this amino acid in the sequence of CDC. The properties of 3 L. monocytogenes strains, a wild type and 2 mutants expressing modified LLO within the cysteine residue, were analyzed in this work. The first of these mutants producing a toxin with cysteine to alanine substitution showed similar features to the wild type except that a thiol-reducing agent was not necessary for hemolytic activity. Another strain secreting LLO containing serine instead of cysteine exhibited strikingly different properties than the wild type. Modified toxin is independent of the reducing reagents, less stable, and shows accelerated kinetics of cytolysis in comparison with the unchanged protein. However, both mutant strains are less invasive in the cell culture model showing the important role of cysteine in L. monocytogenes virulence.

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ISTERI SEBAGAI PENCARI NAFKAH UTAMA: Studi terhadap Perajin Kapuk di Desa Imogiri, Bantul, Yogyakarta

Al-Ahwal Jurnal Hukum Keluarga Islam ◽

10.14421/ahwal.2016.09104 ◽

2017 ◽

Vol 9 (1) ◽

pp. 47

Author(s):

Siti Djazimah ◽

Ihab Habudin

Keyword(s):

Social Interactions ◽

Negative Impact ◽

Economic Independence ◽

The Social ◽

The Family ◽

Wage Earners ◽

Positive Traits ◽

The Impact ◽

The Village

Islam has expressly regulate the division of tasks and roles between husbands and wives fairly. Although the husband is obliged to provide sustenance for his wife and children, but the family law of Islam does not forbid a wife from helping her husband in making a living with her husband's consent and does not interfere with her obligations as a housewife. There is a wife in a family of craftsmen in the village of Tegal Kembang, Imogiri, Yogyakarta, which acts as the main breadwinners for their families. This article examines the wives who work as the wage earners by using the concept of maqa> s} id ash-shari'ah < 'ah. The impact that emerges of the role of the kapok craftsmen woman is more on the impacts that are in positive traits and it is associated with the hajjiy and daruriy needs. The wife who has an income has the economic independence power that can even sustain the needs of the family. Social interactions that occur in kapok craftsmen community, make a strong emotional connection between kapok craftsmen. While the social interaction with the "outside world" (consumers) clearly provides insight of the Kapok Craftsmen. As for the negative impact of the mother's role of Kapok craftsman towards parenting does not seem significant.[Islam secara tegas telah mengatur tentang pembagian tugas dan peran antara suami dan istri secara adil. Walaupun suami berkewajiban memberi nafkah kepada isteri dan anak-anaknya, tetapi hukum keluarga islam tidak melarang istri membantu suaminya dalam mencari nafkah dengan persetujuan suaminya dan tidak mengganggu kewajibannya sebagai seorang ibu rumah tangga. Ada istri pada keluarga perajin kapuk di dusun Tegal Kembang, Imogiri, Bantul, Yogyakarta, yang berperan sebagai pencari nafkah utama bagi keluarganya. Tulisan ini mengkaji para isteri yang bekerja sebagai pencari nafkah dengan menggunakan konsep maqa>s}id asy-syari<‘ah. Dampak yang ditimbulkan dari peran yang dijalankan para ibu perajin kapuk adalah lebih pada dampak yang sifatnya positif dan hal ini terkait dengan kebutuhan yang sifatnya daruriy dan hajjiy. Para isteri yang mempunya penghasilan tersebut memiliki kemandirian dalam ekonomi bahkan dapat menopang kebutuhan keluarga. Interaksi sosial yang terjadi dalam komuitas perajin kapuk, menjadikan kuatnya hubungan emosional di antara perajin kapuk. Sementara interaksi sosial dengan “dunia luar” (konsumen) jelas memberikan wawasan perajin kapuk semakin bertambah. Adapun dampak negatif peran ibu sebagai perajin kapuk terhadap pengasuhan anak tidak nampak secara signifikan.]

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Optimizing COVID-19 control with asymptomatic surveillance testing in a university environment

10.1101/2020.11.12.20230870 ◽

2020 ◽

Author(s):

Cara E. Brook ◽

Graham R Northrup ◽

Alexander J. Ehrenberg ◽

Jennifer A. Doudna ◽

Mike Boots ◽

...

Keyword(s):

Group Size ◽

Behavioral Interventions ◽

Process Model ◽

Effective Means ◽

Population Level ◽

Transmission Risk ◽

Contact Tracing ◽

Control Group ◽

University Environment ◽

Size Limits

The high proportion of transmission events derived from asymptomatic or presymptomatic infections make SARS-CoV-2, the causative agent in COVID-19, difficult to control through the traditional non-pharmaceutical interventions (NPIs) of symptom-based isolation and contact tracing. As a consequence, many US universities have developed asymptomatic surveillance testing labs, to augment existing NPIs and control outbreaks on campus. We built a stochastic branching process model of COVID-19 dynamics to advise optimal control strategies in a university environment. Our model combines behavioral interventions in the form of group size limits to deter superspreading, symptom-based isolation, and contact tracing, with asymptomatic surveillance testing. We find that behavioral interventions offer a cost-effective means of epidemic control: group size limits of six or fewer greatly reduce superspreading, and rapid isolation of symptomatic infections can halt rising epidemics, depending on the frequency of asymptomatic transmission in the population. Surveillance testing can overcome uncertainty surrounding asymptomatic infections, with the most effective approaches prioritizing frequent testing with rapid turnaround time to isolation over test sensitivity. Importantly, contact tracing amplifies population-level impacts of all infection isolations, making even delayed interventions effective. Combination of behavior-based NPIs and asymptomatic surveillance also reduces variation in daily case counts to produce more predictable epidemics. Furthermore, targeted, intensive testing of a minority of high transmission risk individuals can effectively control the COVID-19 epidemic for the surrounding population. We offer this blueprint and easy-to-implement modeling tool to other academic or professional communities navigating optimal return-to-work strategies for the 2021 year.

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‘Blood Doesn’t Become Water’? Syrian Social Relations during Displacement

Journal of Refugee Studies ◽

10.1093/jrs/fey059 ◽

2018 ◽

Vol 33 (3) ◽

pp. 555-576 ◽

Cited By ~ 1

Author(s):

Michelle Lokot

Keyword(s):

Social Interactions ◽

Social Relations ◽

Social Dynamics ◽

Middle Eastern ◽

Power Dynamics ◽

Syrian Refugees ◽

Family Structures ◽

The Family

Abstract Humanitarian discourses emphasize that displacement results in disruptions to family structures. This article challenges simplistic descriptions of change during displacement, highlighting the powerful role of the family in Middle Eastern societies through an anthropological exploration of social relations among Syrian refugees in Jordan. It contributes to academic analysis on social relations among refugees by presenting a more mixed picture of social dynamics within and outside the family—both before conflict and during displacement. It explores how the hold of the family among Syrians may limit social interactions with ‘outsiders’ during displacement, as well as how displacement may offer opportunities for tighter social regulations to be unravelled. These findings highlight that social relations among refugees must be analysed more carefully, and with consideration of intersectional power dynamics.

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Switching number in pronouns as social indices in Dream of the Red Chamber

East Asian Pragmatics ◽

10.1558/eap.v1i2.30052 ◽

2016 ◽

Vol 1 (2) ◽

pp. 209-230 ◽

Cited By ~ 1

Author(s):

Cher Leng Lee

Keyword(s):

Social Network ◽

Social Interactions ◽

Social Hierarchy ◽

Chinese Community ◽

Group Awareness ◽

European Languages ◽

The People ◽

The Social ◽

The Family

The role of pronouns as indications of power and solidarity in social interactions has long been a fascinating topic, especially within the Indo-European languages. It is much more complex in a traditional Chinese community, in which group identity and group awareness are always above that of an individual. The family is a strictly hierarchical community, generally governed by age and patriarchal hierarchy, from grandparents to parents. This study examines a particular phenomenon of switched number in the pronouns in Dream of the Red Chamber. For example, plural pronouns are used to refer to a singular referent and vice versa. It shows that one has to understand the usage of these pronouns in the Chinese context in which the interlocutors are well aware of the social hierarchy. The pragmatic use of these switches indicates the attitudes of the speakers toward the people they are speaking to or referring to. The switching of pronoun number is a form of social indexicality, showing attitudes in the context of hierarchical social network.

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Protective humoral and cellular immune responses to SARS-CoV-2 persist up to 1 year after recovery

Nature Communications ◽

10.1038/s41467-021-25312-0 ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 2

Author(s):

Chengqian Feng ◽

Jingrong Shi ◽

Qinghong Fan ◽

Yaping Wang ◽

Huang Huang ◽

...

Keyword(s):

Protective Immunity ◽

Critical Factor ◽

Population Level ◽

Effective Population ◽

Cellular Immune Responses ◽

Neutralizing Capacity ◽

One Year ◽

Cellular Immune ◽

Kinetics Of

AbstractSARS-CoV-2 vaccination has been launched worldwide to build effective population-level immunity to curb the spread of this virus. The effectiveness and duration of protective immunity is a critical factor for public health. Here, we report the kinetics of the SARS-CoV-2 specific immune response in 204 individuals up to 1-year after recovery from COVID-19. RBD-IgG and full-length spike-IgG concentrations and serum neutralizing capacity decreases during the first 6-months, but is maintained stably up to 1-year after hospital discharge. Even individuals who had generated high IgG levels during early convalescent stages had IgG levels that had decreased to a similar level one year later. Notably, the RBD-IgG level positively correlates with serum neutralizing capacity, suggesting the representative role of RBD-IgG in predicting serum protection. Moreover, viral-specific cellular immune protection, including spike and nucleoprotein specific, persisted between 6 months and 12 months. Altogether, our study supports the persistence of viral-specific protective immunity over 1 year.

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Assessing asymptomatic, pre-symptomatic and symptomatic transmission risk of SARS-CoV-2

Clinical Infectious Diseases ◽

10.1093/cid/ciab271 ◽

2021 ◽

Author(s):

Peng Wu ◽

Fengfeng Liu ◽

Zhaorui Chang ◽

Yun Lin ◽

Minrui Ren ◽

...

Keyword(s):

Control Measures ◽

Transmission Risk ◽

Contact Tracing ◽

Secondary Infections ◽

Different Types ◽

Early Case ◽

Symptom Status ◽

Early Case Detection ◽

Index Cases ◽

Close Contacts

Abstract Background The relative contributions of asymptomatic, pre-symptomatic and symptomatic transmission of SARS-CoV-2 have not been clearly measured although control measures may differ in response to the risk of spread posed by different types of cases. Methods We collected detailed information on transmission events and symptom status based on laboratory-confirmed patient data and contact tracing data from four provinces and one municipality in China. We estimated the variation in risk of transmission over time, and the severity of secondary infections, by symptomatic status of the infector. Results There were 393 symptomatic index cases with 3136 close contacts and 185 asymptomatic index cases with 1078 close contacts included into the study. The secondary attack rate among close contacts of symptomatic and asymptomatic index cases were 4.1% (128/3136) and 1.1% (12/1078), respectively, corresponding to a higher transmission risk from symptomatic cases than from asymptomatic cases (OR: 3.79, 95% CI: 2.06, 6.95). Approximately 25% (32/128) and 50% (6/12) of the infected close contacts were asymptomatic from symptomatic and asymptomatic index cases, respectively, while more than one third (38%) of the infections in the close contacts of symptomatic cases were attributable to exposure to the index cases before symptom onset. Infected contacts of asymptomatic index cases were more likely to be asymptomatic and less likely to be severe. Conclusions Asymptomatic and pre-symptomatic transmission play an important role in spreading infection, although asymptomatic cases pose a lower risk of transmission than symptomatic cases. Early case detection and effective test-and-trace measures are important to reduce transmission.

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