scholarly journals The role of lambs in louping-ill virus amplification

Parasitology ◽  
2000 ◽  
Vol 120 (2) ◽  
pp. 97-104 ◽  
Author(s):  
M. K. LAURENSON ◽  
R. NORMAN ◽  
H. W. REID ◽  
I. POW ◽  
D. NEWBORN ◽  
...  
Keyword(s):  
Farming Systems ◽  
Early Summer ◽  
Infection Rates ◽  
Force Of Infection ◽  
High Infection ◽  
Louping Ill ◽  
Hill Farming ◽  
The Relationship ◽  
Colostral Antibody

In some areas of Scotland, the prevalence of louping-ill virus has not decreased despite the vaccination of replacement ewes for over 30 years. The role of unvaccinated lambs in viral persistence was examined through a combination of an empirical study of infection rates of lambs and mathematical modelling. Serological sampling revealed that most lambs were protected by colostral immunity at turnout in May/June but were fully susceptible by the end of September. Between 8 and 83% of lambs were infected over the first season, with seroconversion rates greater in late rather than early summer. The proportion of lambs that could have amplified the louping-ill virus was low, however, because high initial titres of colostral antibody on farms with a high force of infection gave protection for several months. A simple mathematical model suggested that the relationship between the force of infection and the percentage of lambs that became viraemic was not linear and that the maximum percentage of viraemic lambs occurred at moderately high infection rates. Examination of the conditions required for louping-ill persistence suggested that the virus could theoretically persist in a sheep flock with over 370 lambs, if the grazing season was longer than 130 days. In practice, however, lamb viraemia is not a general explanation for louping-ill virus persistence as these conditions are not met in most management systems and because the widespread use of acaracides in most tick-affected hill farming systems reduces the number of ticks feeding successfully.

On the interpretation of age—prevalence curves for schistosome infections of host snails

Parasitology ◽  
1989 ◽  
Vol 99 (1) ◽  
pp. 47-56 ◽  
Author(s):  
M. E. J. Woolhouse
Keyword(s):  
Survival Rate ◽  
Field Studies ◽  
Significant Loss ◽  
High Rate ◽  
Snail Population ◽  
Infection Rates ◽  
Force Of Infection ◽  
Age Dependent ◽  
The Relationship ◽  
Patent Infection

SUMMARYThe prevalence of schistosome infections in intermediate host snails varies with snail age. The relationship between age and prevalence, the age—prevalence curve, is complex and may vary in space and time, and among parasite—host species. Field studies show that the shape of the age—prevalence curve may be seasonally variable, and that at some times there may be a decline in prevalence among older snails. This paper attempts to explain these observations in terms of the underlying epidemiological processes. A discrete-time version of Muench's catalytic model for age-dependent infection is developed. Model simulations were carried out using life-history and epidemiological parameters derived from studies ofSchistosoma haematobium—Bulinus globususin Zimbabwe. Analysis of model behaviour identifies aspects of the schistosome— snail interaction that affect the shape of the age—prevalence curve. The following features can result in a decline in prevalence among older snails. (1) A decrease in the survival rate of patent infected snails with age. (2) A decrease in the force of infection with age. (3) A high rate of loss of infection. (4) A heterogeneity in the snail population such that the probability of infection is correlated with snail fecundity. (This would occur if there existed a spatial correlation between force of infection and fecundity, or if there were a correlation between fecundity and susceptibility.) The evidence for the occurrence of these features in the field is assessed. Survival rate is related more closely to the duration of patent infection than to ageper se. The evidence for age-dependent force of infection is equivocal. Significant loss-of-infection rates have yet to be demonstrated. Heterogeneities in force of infection and fecundity have been reported and, for the Zimbabwe data, this mechanism can explain seasonally in the age—prevalence curve as a function of known seasonal variation in the force of infection and snail fecundity.

scholarly journals Boda-boda, Youth Employment and Globalisation in Uganda

2021 ◽  
Vol 7 (1) ◽  
pp. 1-9
Author(s):  
Charles Amone
Keyword(s):  
Skills Training ◽  
Youth Employment ◽  
Infection Rates ◽  
Business Skills ◽  
Illicit Trade ◽  
International Borders ◽  
Recent Scholarship ◽  
High Infection ◽  
Transport Industry

Formerly shunned due its notoriety for facilitating illicit trade and transporting criminals across Uganda’s international borders, the boda-boda transport industry gained fame in recent years and has become the second largest employer of youths all over Uganda, after agriculture. Recent scholarship on the bodaboda industry has however, concentrated on the risks embedded in it including high infection rates of HIV among the drivers and the daily accidents reported. Little attention has been paid to the contribution of the industry in youth employment. This paper discusses the role of boda-boda transport industry in solving the problem of unemployment among the youths in Uganda. The author interviewed seventeen boda-boda drivers in Uganda and thirty-four of their family members to establish how this transport business has impacted on employment opportunities, financial independence and globalisation of youths. The study revealed that whereas many youths have dropped out of school to take up the boda-boda business, profits of this trade have facilitated the education of some young people in Uganda and enabled them to globally connect with youths across the globe. The study recommends sensitisation, business skills training as well as adult and distant education opportunities for the youthful motorcycle drivers

scholarly journals Are countries precautionary actions against COVID-19 effective? An assessment study of 175 countries worldwide

2020 ◽  
Author(s):  
Thamir M Alshammari ◽  
Khalidah Alenzi ◽  
Fatemah Alnofal ◽  
Ghada Fradees ◽  
Ali Altebainawi
Keyword(s):  
Health Care ◽  
Severe Acute Respiratory Syndrome ◽  
Observational Study ◽  
Infection Rate ◽  
Infection Rates ◽  
Financial Systems ◽  
School Closures ◽  
Assessment Study ◽  
High Infection ◽  
The Relationship

Background The Coronavirus Disease 2019 (COVID-19) pandemic has affected many countries negatively, particularly in terms of their health care and financial systems. Numerous countries have attempted to employ precautions to address this pandemic. Objective This study was aimed at exploring and assessing the precautionary actions taken by 175 countries on six continents to prevent the spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Methods An observational study was conducted based on data collected during the period from December 31, 2019, until the end of April 2020. Several data were extracted, including information related to the date of the first reported case of SARS-CoV-2, total confirmed cases, total active cases, and more. In addition, seven validated indicators were used to assess the countries preparedness and precautionary actions. Results A total of 175 countries were included in the study. The total COVID-19 infection rate increased exponentially and rapidly in North America and Europe from March to April. The application of the precautions (indicators) varied between countries. School closures, quarantines and curfews were the most applied indicators among all countries. As for the relationship between the indicators and their effects on the infection rate, Italy and Spain were the top countries in Europe and adopted all indicators. Nevertheless, they faced high infection rates: 239,639 and 205,463 COVID-19 cases in Spain, and Italy, respectively. Conclusion The precautionary actions might have played a role in limiting the spread of COVID-19 in several countries. However, many countries did not benefit from applying these indicators.

scholarly journals Messages in Conflict: Examining Leadership Communication during the COVID-19 Pandemic in the U.S.

2021 ◽  
Vol 4 (3) ◽  
pp. 485-516
Author(s):  
Deborah Sellnow-Richmond ◽  
Marta\ Lukacovic ◽  
Scott Sellnow-Richmond ◽  
Lynzee Kraushaar
Keyword(s):  
Mitigation Measures ◽  
Infection Rates ◽  
Leadership Communication ◽  
Perceived Severity ◽  
Important Time ◽  
Perceptions Of Leadership ◽  
One Year ◽  
The Relationship ◽  
The U.S

One year into the COVID-19 pandemic, the U.S. had lost over a half million lives to the virus. Organizations had to shift the way they operated, requiring effective communication to help employees transition. This study examines two important time periods during the pandemic: early May, just after stay-at-home orders began to be lifted, and late November, as infection rates soared. This study quantitatively examines the role of perceived severity, organizational trust, reputation, and credibility on participants employed during the pandemic expectations of leadership at the organizational, state, and federal levels. Then, participants were interviewed to understand perceptions of leadership. Results illustrate the relationship between perceived severity of the threat and trust in leadership and uncertainty about mitigation measures from state and federal levels.

scholarly journals The epidemiology of louping ill in Ayrshire: the first year of studies in sheep

1964 ◽  
Vol 62 (1) ◽  
pp. 53-68 ◽  
Author(s):  
C. E. Gordon Smith ◽  
Dolores A McMahon ◽  
K. J O'Reilly ◽  
A. L Wilson ◽  
J. M Robertson
Keyword(s):  
Neutralizing Antibody ◽  
Early Summer ◽  
Control Measures ◽  
Clinical Disease ◽  
First Year ◽  
Infection Rates ◽  
Long Term Study ◽  
Louping Ill ◽  
The Difference ◽  
Almost All

1. Following an epizootic of louping ill on certain farms in south-west Ayrshire in 1960, a long-term study of several farms was initiated.2. The flocks on two hirsels of one farm were studied during spring and early summer of 1961. Although only one lamb death was confirmed as due to louping ill, the infection rates in sentinel hoggs on the two hirsels were 50–60. and 11% respectively. The difference between the hirsels is probably attributable to the difference in the amount of tick habitat on them.3. The ewes were bled in March and June and their lambs in June. Haemagglutinin inhibition (HI) and neutralization tests revealed that the HI antibody is much shorter lasting than neutralizing antibody. Many ewes, therefore, had neutralizing but not HI antibody. Otherwise agreement between the tests was good. In March almost all the ewes aged 3 years or more had antibody. Of the gimmers (2-year-olds) about two-thirds on one hirsel and one-third on the other had antibody in March: by June almost all the former and about half of the latter had antibody.4. About two-thirds of the lambs had the same antibody status as their mothers in June and almost all the rest had less antibody than their mothers. Serological evidence suggestive of louping ill without recognizable clinical disease was found in six lambs and a further lamb recovered from clinical disease.5. Revaccination of two-thirds of the flock failed to cause any detectable change in antibody status.6. The epidemiology and pathogenesis are discussed in relation to immunity and infection rates, and to the design of control measures.We are greatly indebted to the late Mr James Murdoch at Dalmellington, Mr John Murdoch at Dalcairnie Farm, and Mr David Murdoch at Knockgray Farm for permission to work on their farms and for all the help they gave us during the study.

The regulation of populations ofOstertagia ostertagiin calves

Parasitology ◽  
1970 ◽  
Vol 61 (3) ◽  
pp. 435-447 ◽  
Author(s):  
J. F. Michel
Keyword(s):  
Infection Rate ◽  
Small Proportion ◽  
Post Mortem ◽  
Fourth Stage ◽  
Infection Rates ◽  
Ostertagia Ostertagi ◽  
High Infection ◽  
The Relationship

The course of the worm burdens of calves infected daily with larvae ofOstertagia ostertagiat five different rates was studied by making post-mortem worm counts on groups of calves killed after experiencing infection for different periods of time.The relationship between worm numbers and infection rates together with evidence that a turnover of worms occurred, led to the conclusion that burdens of adult worms were regulated primarily by a loss of worms at a rate proportional to the number present.Further, estimates based on the number of developing fourth-stage larvae indicated that the proportion of the larvae administered which became established decreased gradually as the experiment progressed.At very low infection rates, the rate of turnover of the worms was slower than at high infection rates but in all groups it remained constant through the 6 months duration of the experiment.The development of a small proportion of the larvae administered was arrested at the early fourth stage. At the highest infection rate used, the proportion of worms that became inhibited was somewhat greater.

scholarly journals «SPECIAL ASSIGNMENT—42». ON THE DEPLOYMENT OF THE CRIMEAN UNDERGROUND IN THE SUMMER OF 1942

2021 ◽  
Vol 7 (73) (2) ◽  
pp. 142-150
Author(s):  
S. N. Tkachenko
Keyword(s):  
Early Summer ◽  
Special Place ◽  
The Relationship

The underground struggle of the Crimeans during the years of the occupation of Crimea (1941–1944), despite a certain range of studies, has been extremely poorly studied. A special place in this is the relationship between the underground and partisan formations, and in particular the role of the latter in the formation of patriotic resistance through underground forms of struggle. This article reveals the meaning and significance of the event, which became the most important example of such interaction – «Special Assignment-42», and its place in the deployment of the activities of the underground in the second half of the summer of 1942. On the whole, the circumstances indicated in the article make it possible to speak of a clear failure of the plan of «Special Assignment–42», which, although it saved the partisan detachments from some of the non-combatant people, did not affect the actual expansion of the underground movement. The underground expanded thanks to the independent activities of groups of Soviet patriots and the work of party representatives sent to the occupied settlements in the spring and early summer of 1942. And the partisan formations still had to be reorganized and partially evacuated to the «mainland».

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

Staring Down Death

Crisis ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Thomas E. Joiner ◽  
Melanie A. Hom ◽  
Megan L. Rogers ◽  
Carol Chu ◽  
Ian H. Stanley ◽  
...  
Keyword(s):  
Suicide Risk ◽  
Clinical Utility ◽  
Blink Rate ◽  
Specific Task ◽  
Careful Planning ◽  
Eye Blink ◽  
Eye Blinks ◽  
Potential Clinical Utility ◽  
The Relationship

Abstract. Background: Lowered eye blink rate may be a clinically useful indicator of acute, imminent, and severe suicide risk. Diminished eye blink rates are often seen among individuals engaged in heightened concentration on a specific task that requires careful planning and attention. Indeed, overcoming one’s biological instinct for survival through suicide necessitates premeditation and concentration; thus, a diminished eye blink rate may signal imminent suicidality. Aims: This article aims to spur research and clinical inquiry into the role of eye blinks as an indicator of acute suicide risk. Method: Literature relevant to the potential connection between eye blink rate and suicidality was reviewed and synthesized. Results: Anecdotal, cognitive, neurological, and conceptual support for the relationship between decreased blink rate and suicide risk is outlined. Conclusion: Given that eye blinks are a highly observable behavior, the potential clinical utility of using eye blink rate as a marker of suicide risk is immense. Research is warranted to explore the association between eye blink rate and acute suicide risk.

Parenting Behaviors and Anxiety in Young Adults

2015 ◽  
Vol 36 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Erin N. Stevens ◽  
Joseph R. Bardeen ◽  
Kyle W. Murdock
Keyword(s):  
Effortful Control ◽  
Parenting Behaviors ◽  
Protective Role ◽  
Anxiety Symptoms ◽  
Interactive Effects ◽  
Parental Overprotection ◽  
High Control ◽  
Development Of Anxiety ◽  
The Relationship

Parenting behaviors – specifically behaviors characterized by high control, intrusiveness, rejection, and overprotection – and effortful control have each been implicated in the development of anxiety pathology. However, little research has examined the protective role of effortful control in the relation between parenting and anxiety symptoms, specifically among adults. Thus, we sought to explore the unique and interactive effects of parenting and effortful control on anxiety among adults (N = 162). Results suggest that effortful control uniquely contributes to anxiety symptoms above and beyond that of any parenting behavior. Furthermore, effortful control acted as a moderator of the relationship between parental overprotection and anxiety, such that overprotection is associated with anxiety only in individuals with lower levels of effortful control. Implications for potential prevention and intervention efforts which specifically target effortful control are discussed. These findings underscore the importance of considering individual differences in self-regulatory abilities when examining associations between putative early-life risk factors, such as parenting, and anxiety symptoms.

Sign in / Sign up

Export Citation Format

Share Document