Further studies on epidemiological factors influencing control of banana bunchy top disease and evaluation of control measures by computer simulation

1987 ◽  
Vol 38 (2) ◽  
pp. 373
Author(s):  
RN Allen
Keyword(s):  
Disease Control ◽  
Control Measure ◽  
Significant Loss ◽  
Control Measures ◽  
Disease Spread ◽  
Disease Symptoms ◽  
Control Disease ◽  
Banana Leaves ◽  
Time Required ◽  
Apparently Healthy

The basic infection rate of bunchy top disease in established bananas averaged 0.0342 new infections per infectious plant per day, but varied seasonally with a maximum in summer. The mean distance of spread for the aphid vector was 15.2 m. The latent period was 59.8 days and correlated with the time required for the growth of 3.7 new banana leaves. A microcomputer program was written to simulate spread of banana bunchy top disease in space and time. In the absence of disease control, disease spread from an initial primary infection in July or January to 124 or 153 infected plants, respectively, in one year. When disease control was maintained by removing diseased plants whenever the number of infected plants exceeded a given threshold, the numbers of diseased plants detected each inspection were positively correlated with the infection threshold, but the numbers of inspections required to maintain control increased markedly as the infection threshold was decreased. A practice of removing apparently healthy plants within 5 m of plants detected with bunchy top disease symptoms in five or more leaves was found to locate about 30% of the remaining undetected infected plants when disease was first detected in a plantation. However, its use as a routine control measure was ineffective in reducing the number of inspections required to maintain control or in reducing the risk of disease spreading to adjoining plantations. Removal of apparently healthy plants within 5 m had some bearing on disease control when applied around plants with disease symptoms in two leaves or less, but also caused a significant loss of healthy plants.

Corrigendum - Further studies on epidemiological factors influencing control of banana bunchy top disease and evaluation of control measures by computer simulation

1987 ◽  
Vol 38 (2) ◽  
pp. 373
Author(s):  
RN Allen
Keyword(s):  
Disease Control ◽  
Control Measure ◽  
Significant Loss ◽  
Control Measures ◽  
Disease Spread ◽  
Disease Symptoms ◽  
Control Disease ◽  
Banana Leaves ◽  
Time Required ◽  
Apparently Healthy

The basic infection rate of bunchy top disease in established bananas averaged 0.0342 new infections per infectious plant per day, but varied seasonally with a maximum in summer. The mean distance of spread for the aphid vector was 15.2 m. The latent period was 59.8 days and correlated with the time required for the growth of 3.7 new banana leaves. A microcomputer program was written to simulate spread of banana bunchy top disease in space and time. In the absence of disease control, disease spread from an initial primary infection in July or January to 124 or 153 infected plants, respectively, in one year. When disease control was maintained by removing diseased plants whenever the number of infected plants exceeded a given threshold, the numbers of diseased plants detected each inspection were positively correlated with the infection threshold, but the numbers of inspections required to maintain control increased markedly as the infection threshold was decreased. A practice of removing apparently healthy plants within 5 m of plants detected with bunchy top disease symptoms in five or more leaves was found to locate about 30% of the remaining undetected infected plants when disease was first detected in a plantation. However, its use as a routine control measure was ineffective in reducing the number of inspections required to maintain control or in reducing the risk of disease spreading to adjoining plantations. Removal of apparently healthy plants within 5 m had some bearing on disease control when applied around plants with disease symptoms in two leaves or less, but also caused a significant loss of healthy plants.

scholarly journals Individually Optimal Choices can be Collectively Disastrous in COVID-19 Disease Control

2021 ◽  
Author(s):  
Madison Stoddard ◽  
Debra Van Egeren ◽  
Kaitlyn Johnson ◽  
Smriti Rao ◽  
Josh Furgeson ◽  
...  
Keyword(s):  
Public Health ◽  
Disease Control ◽  
Control Measures ◽  
Disease Spread ◽  
Complete Suppression ◽  
Natural Immunity ◽  
Endemic Disease ◽  
Health Measures ◽  
The Impact

Abstract Background: The word ‘pandemic’ conjures dystopian images of bodies stacked in the streets and societies on the brink of collapse. Despite this frightening picture, denialism and noncompliance with public health measures are common in the historical record, for example during the 1918 Influenza pandemic or the 2015 Ebola epidemic. The unique characteristics of SARS-CoV-2—its high basic reproduction number (R0), time-limited natural immunity and considerable potential for asymptomatic spread—exacerbate the public health repercussions of noncompliance with interventions (such as vaccines and masks) to limit disease transmission. Our work explores the rationality and impact of noncompliance with COVID-19 disease control measures. Methods: In this work, we used game theory to explore when noncompliance confers a perceived benefit to individuals. We then used epidemiological modeling to predict the impact of noncompliance on control of COVID-19, demonstrating that the presence of a noncompliant subpopulation prevents suppression of disease spread. Results: Our modeling demonstrating that noncompliance is a Nash equilibrium under a broad set of conditions, and that the existence of a noncompliant population can result in extensive endemic disease in the long-term after a return to pre-pandemic social and economic activity. Endemic disease poses a threat for both compliant and noncompliant individuals; all community members are protected if complete suppression is achieved, which is only possible with a high degree of compliance. For interventions that are highly effective at preventing disease spread, however, the consequences of noncompliance are borne disproportionately by noncompliant individuals. Conclusions: In sum, our work demonstrates the limits of free-market approaches to compliance with disease control measures during a pandemic. The act of noncompliance with disease intervention measures creates a negative externality, rendering COVID-19 disease control ineffective in the short term and making complete suppression impossible in the long term. Our work underscores the importance of developing effective strategies for prophylaxis through public health measures aimed at complete suppression and the need to focus on compliance at a population level.

scholarly journals Knowledge Status and Disease Control Practices of Cassava Farmers in Delta State, Nigeria: Implications for Extension Delivery

2019 ◽  
Vol 4 (1) ◽  
pp. 173-186
Author(s):  
Solomon Okeoghene Ebewore ◽  
Rodney Akpoviri Isiorhovoja
Keyword(s):  
Disease Control ◽  
Control Measure ◽  
Sampling Technique ◽  
Simple Random Sampling ◽  
Control Measures ◽  
Farm Size ◽  
Sources Of Information ◽  
Good Government ◽  
And Control ◽  
The Relationship

AbstractThe study assessed the knowledge and control of cassava diseases by farmers in Delta State, Nigeria and the resultant implication for agricultural extension. Data were obtained from 569 cassava farmers by a simple random sampling technique. Data were analyzed by means, percentage, frequency counts and binary logit model. Mean results depicted that cassava farmers in the area were 42.5 years old, spent 13 years in schooling, had a farming experience of 9.5 years and had poor (1.68) annual extension contacts. Extension contact and friends and neighbours were the major sources of information on cassava disease control. Results of the logit regression of the relationship between farmers’ characteristics and knowledge of cassava diseases gave an R2 value of 0.74 indicating that age (negative coefficient), education, farming experience, farm size and extension contact were statistically significant in explaining cassava farmers knowledge of disease control measures. Logit estimates for control of diseases indicated that age, farming experience, farm size and extension contact were statistically significant at P<0.05. Although education was crucial in determining farmers’ knowledge, it was not significant in determining adoption of control measures. The study recommends urgent and good extension contact, good government policy on enlightenment of farmers to improve not only farmers’ knowledge but their adoption of disease control measure as well.

scholarly journals African Swine Fever in a Bulgarian Backyard Farm—A Case Report

2019 ◽  
Vol 6 (4) ◽  
pp. 94 ◽  
Author(s):  
Laura Zani ◽  
Klaas Dietze ◽  
Zlatina Dimova ◽  
Jan Hendrik Forth ◽  
Daniel Denev ◽  
...  
Keyword(s):  
Case Report ◽  
Disease Control ◽  
African Swine Fever ◽  
Control Measures ◽  
Disease Spread ◽  
Effective Vaccine ◽  
Small Scale ◽  
Domestic Pig ◽  
Pig Farms ◽  
Time Point

African swine fever (ASF) is one of the most threatening diseases for the pig farming sector worldwide. As an effective vaccine is lacking, strict application of control measures is the only way to fight the disease in both industrial farms and backyard holdings. With generally low biosecurity standards, the latter are at particular risk for disease introduction and offer challenging conditions for disease control. In the following case report, we describe the overall course of an ASF outbreak in a Bulgarian backyard farm and the implemented control measures. Farm facilities and available data have been investigated to estimate the possible source, spread and time point of virus introduction. Contact with contaminated fomites entering the stable via human activities was regarded to be the most likely introduction route. The slow disease spread within the farm contributes to the hypothesis of a moderate contagiosity. As no further ASF outbreaks have been detected in domestic pig farms in the region, it could be demonstrated that successful disease control in small-scale farms can be reached. Thus, the report contributes to a better understanding of ASF in the backyard sector.

scholarly journals Infection Studies of Mycosphaerella fijiensis on Banana and the Control of Black Sigatoka with Chlorothalonil

Plant Disease ◽  
1998 ◽  
Vol 82 (11) ◽  
pp. 1185-1190 ◽  
Author(s):  
J. R. Washington ◽  
J. Cruz ◽  
F. Lopez ◽  
M. Fajardo
Keyword(s):  
Disease Control ◽  
Leaf Surface ◽  
Infected Leaf ◽  
Mycosphaerella Fijiensis ◽  
Black Sigatoka ◽  
Abaxial Surface ◽  
Disease Symptoms ◽  
Adaxial Surface ◽  
Abaxial Leaf Surface ◽  
Banana Leaves

Infection studies with Mycosphaerella fijiensis, causal agent of black Sigatoka disease of banana (Musa AAA), demonstrated that the abaxial leaf surface is the primary infection site. Inoculation of banana plants with M. fijiensis ascospores on the abaxial surface of young leaves resulted in disease symptoms in 100% of the leaves inoculated within 18 to 30 days; whereas only 5% of the leaves inoculated on the adaxial surface showed black Sigatoka symptoms within 10 weeks. Disease symptoms appeared more rapidly on the new, emerging leaves than on the first and second fully expanded leaves. Application of chlorothalonil (1.08 kg a.i. ha-1) to the abaxial surface of emerging leaves resulted in 99 to 100% disease control in the treated area. When the emerging leaf was not sprayed until fully expanded, disease control was reduced to 76 to 80%. Application of chlorothalonil to the adaxial surface of banana leaves had little or no impact on disease control. Chlorothalonil arrested hyphal growth when applied to banana leaves after ascospores had already germinated and reduced the rate of lesion expansion when applied to the abaxial leaf surface after symptom appearance. Chlorothalonil was less effective than systemic fungicides in reducing production of M. fijiensis pseudothecia in infected tissue. When systemic and protectant fungicides were applied to infected leaf tissue, none of the fungicides affected the viability of ascospores that were discharged from pseudothecia produced in that tissue. For successful control of black Sigatoka with chlorothalonil, deposition of the fungicide on the abaxial leaf surface is essential.

scholarly journals When to kill a cull: factors affecting the success of culling wildlife for disease control

2019 ◽  
Vol 16 (152) ◽  
pp. 20180901 ◽  
Author(s):  
Jamie C. Prentice ◽  
Naomi J. Fox ◽  
Michael R. Hutchings ◽  
Piran C. L. White ◽  
Ross S. Davidson ◽  
...  
Keyword(s):  
Disease Control ◽  
Control Strategies ◽  
Wildlife Disease ◽  
Policy Implications ◽  
Disease Spread ◽  
Factors Affecting ◽  
Badger Culling ◽  
Population Reduction ◽  
Control Disease ◽  
The Uk

Culling wildlife to control disease can lead to both decreases and increases in disease levels, with apparently conflicting responses observed, even for the same wildlife–disease system. There is therefore a pressing need to understand how culling design and implementation influence culling's potential to achieve disease control. We address this gap in understanding using a spatial metapopulation model representing wildlife living in distinct groups with density-dependent dispersal and framed on the badger–bovine tuberculosis (bTB) system. We show that if population reduction is too low, or too few groups are targeted, a ‘perturbation effect’ is observed, whereby culling leads to increased movement and disease spread. We also demonstrate the importance of culling across appropriate time scales, with otherwise successful control strategies leading to increased disease if they are not implemented for long enough. These results potentially explain a number of observations of the dynamics of both successful and unsuccessful attempts to control TB in badgers including the Randomized Badger Culling Trial in the UK, and we highlight their policy implications. Additionally, for parametrizations reflecting a broad range of wildlife–disease systems, we characterize ‘Goldilocks zones’, where, for a restricted combination of culling intensity, coverage and duration, the disease can be reduced without driving hosts to extinction.

Characterizing the effectiveness of COVID-19 mitigation measures: A data-centric approach (Preprint)

2020 ◽  
Author(s):  
Lukman Olagoke ◽  
Ahmet E. Topcu
Keyword(s):  
Control Measure ◽  
Control Measures ◽  
World Health ◽  
Mitigation Measures ◽  
Effective Control ◽  
The World ◽  
Decision Making Processes ◽  
And Performance ◽  
Health Organization ◽  
The Impact

BACKGROUND COVID-19 represents a serious threat to both national health and economic systems. To curb this pandemic, the World Health Organization (WHO) issued a series of COVID-19 public safety guidelines. Different countries around the world initiated different measures in line with the WHO guidelines to mitigate and investigate the spread of COVID-19 in their territories. OBJECTIVE The aim of this paper is to quantitatively evaluate the effectiveness of these control measures using a data-centric approach. METHODS We begin with a simple text analysis of coronavirus-related articles and show that reports on similar outbreaks in the past strongly proposed similar control measures. This reaffirms the fact that these control measures are in order. Subsequently, we propose a simple performance statistic that quantifies general performance and performance under the different measures that were initiated. A density based clustering of based on performance statistic was carried out to group countries based on performance. RESULTS The performance statistic helps evaluate quantitatively the impact of COVID-19 control measures. Countries tend show variability in performance under different control measures. The performance statistic has negative correlation with cases of death which is a useful characteristics for COVID-19 control measure performance analysis. A web-based time-line visualization that enables comparison of performances and cases across continents and subregions is presented. CONCLUSIONS The performance metric is relevant for the analysis of the impact of COVID-19 control measures. This can help caregivers and policymakers identify effective control measures and reduce cases of death due to COVID-19. The interactive web visualizer provides easily digested and quick feedback to augment decision-making processes in the COVID-19 response measures evaluation. CLINICALTRIAL Not Applicable

scholarly journals COVID-19 in South Korea: Proper timing for Easing Mask mandates after COVID-19 Vaccination

2021 ◽  
pp. 1-9
Author(s):  
Yun-Jung Kang
Keyword(s):  
South Korea ◽  
Disease Control ◽  
Prevention And Control ◽  
Control Measures ◽  
Social Distancing ◽  
Proper Timing ◽  
Control And Prevention ◽  
Prevention And Control Measures ◽  
And Control

Abstract As of 25 July 2021, the Korea Disease Control and Prevention Agency reported 1,422 new COVID-19 cases, 188,848 total cases, and 2.073 total deaths (1.10% fatality rates). Since the first SARS-CoV-2 case was reported, efforts to find a treatment and vaccine against COVID-19 have been widespread. Four vaccines are on the WHO’s emergency use listing and are approved of their usage; BNT162b2, mRNA-1273, AZD1222, and Ad26.COV2.S. Vaccines against SARS-CoV-2 need at least 14 days to achieve effectiveness. Thus, people should abide by prevention and control measures, including wearing masks, washing hands, and social distancing. However, a lot of new cases were reported after vaccinations, as many people did not follow the prevention control measures before the end of the 14 days period. There is no doubt we need to break free from mask mandates. But let us not decide the timing in haste. Even if the mask mandates are eased, they should be changed depending on the number of reported cases, vaccinations, as well as prevention and control measures on how circumstances are changing under the influence of mutant coronavirus.

scholarly journals Using Commercial Compost as Control Measures against Cucumber Root-Rot Disease

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Kamel Kamal Sabet ◽  
Magdy Mohamed Saber ◽  
Mohamed Adel-Aziz El-Naggar ◽  
Nehal Samy El-Mougy ◽  
Hatem Mohamed El-Deeb ◽  
...  
Keyword(s):  
Root Rot ◽  
Control Measure ◽  
Disease Incidence ◽  
Pathogenic Fungi ◽  
Pythium Ultimum ◽  
Control Measures ◽  
Infested Soil ◽  
Fungal Isolates ◽  
Cucumber Root

Five commercial composts were evaluated to suppress the root-rot pathogens (Fusarium solani (Mart.) App. and Wr, Pythium ultimum Trow, Rhizoctonia solani Kuhn, and Sclerotium rolfsii Sacc.) of cucumber plants under in vitro and greenhouse conditions. In vitro tests showed that all tested unautoclaved and unfiltrated composts water extracts (CWEs) had inhibitor effect against pathogenic fungi, compared to autoclaved and filtrated ones. Also, the inhibitor effects of 40 bacteria and 15 fungi isolated from composts were tested against the mycelial growth of cucumber root-rot pathogens. Twenty two bacteria and twelve fungal isolates had antagonistic effect against root-rot pathogens. The antagonistic fungal isolates were identified as 6 isolates belong to the genus Aspergillus spp., 5 isolates belong to the genus Penicillium spp. and one isolate belong to the genus Chaetomium spp. Under greenhouse conditions, the obtained results in pot experiment using artificial infested soil with cucumber root-rot pathogens showed that the compost amended soil reduced the percentage of disease incidence, pathogenic fungi population, and improved the cucumber vegetative parameters as shoot length, root length, fresh weight, and dry weight. These results suggested that composts are consequently considered as control measure against cucumber root-rot pathogens.

Outbreak ofNeisseria meningitidisC in workers at a large food-processing plant in Brazil: challenges of controlling disease spread to the larger community

2011 ◽  
Vol 140 (5) ◽  
pp. 906-915 ◽  
Author(s):  
B. P. M. ISER ◽  
H. C. A. V. LIMA ◽  
C. De MORAES ◽  
R. P. A. De ALMEIDA ◽  
L. T. WATANABE ◽  
...  
Keyword(s):  
Food Processing ◽  
Purpura Fulminans ◽  
Control Measures ◽  
Disease Spread ◽  
Processing Plant ◽  
Sterile Site ◽  
Matched Case ◽  
Epidemiological Link ◽  
Control Study ◽  
Food Processing Plant

SUMMARYAn outbreak of meningococcal disease (MD) with severe morbidity and mortality was investigated in midwestern Brazil in order to identify control measures. A MD case was defined as isolation ofNeisseria meningitidis, or detection of polysaccharide antigen in a sterile site, or presence of clinical purpura fulminans, or an epidemiological link with a laboratory-confirmed case-patient, between June and August 2008. In 8 out of 16 MD cases studied, serogroup C ST103 complex was identified. Five (31%) cases had neurological findings and five (31%) died. The attack rate was 12 cases/100 000 town residents and 60 cases/100 000 employees in a large local food-processing plant. We conducted a matched case-control study of eight primary laboratory-confirmed cases (1:4). Factors associated with illness in single variable analysis were work at the processing plant [matched odds ratio (mOR) 22, 95% confidence interval (CI) 2·3–207·7,P<0·01], and residing <1 year in Rio Verde (mOR 7, 95% CI 1·11–43·9,P<0·02). Mass vaccination (>10 000 plant employees) stopped propagation in the plant, but not in the larger community.

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