scholarly journals Community transmission of influenza A (H1N1)v virus at a rock festival in Belgium, 2-5 July 2009

2009 ◽  
Vol 14 (31) ◽  
Author(s):  
I Gutiérrez ◽  
A Litzroth ◽  
S Hammadi ◽  
H Van Oyen ◽  
C Gérard ◽  
...  
Keyword(s):  
Surveillance System ◽  
Influenza A ◽  
Influenza Pandemic ◽  
Control Measures ◽  
Influenza Like Illness ◽  
Health Authorities ◽  
Influenza A H1n1 ◽  
Community Transmission ◽  
And Control

On 6 July 2009 the Belgian enhanced surveillance system for influenza-like illness among travellers returning from influenza A(H1N1)v affected areas detected a case linked to a rock festival which took place on 2-5 July. The health authorities implemented communication and control measures leading to the detection of aditional cases. This paper describes the outbreak and its impact on the management of the influenza pandemic in Belgium.

scholarly journals Modified surveillance of influenza A(H1N1)v virus infections in France

2009 ◽  
Vol 14 (29) ◽  
Author(s):  
Influenza A(H1N1)v investigation teams
Keyword(s):  
Hospital Care ◽  
Influenza A ◽  
Population Based ◽  
Control Measures ◽  
Virus Infections ◽  
Influenza Like Illness ◽  
Influenza A H1n1 ◽  
Community Transmission

Up to early July 2009, surveillance of H1N1 cases in France was based on the identification of all possible cases in order to implement, around each of them, control measures aimed at delaying the spread of the virus. The global dissemination of the virus and the starting community transmission in France led us to shift to a population-based surveillance relying mainly on the identification and investigation of clusters of influenza-like illness, on the identification and individual follow-up of confirmed hospitalised cases as well as on the monitoring, through various sentinel systems, of the use of ambulatory and hospital care for influenza-like symptoms.

scholarly journals Influenza A(H1N1)v virus infections in Belgium, May-June 2009

2009 ◽  
Vol 14 (28) ◽  
Author(s):  
Collective Belgian working group on influenza A(H1N1)v
Keyword(s):  
North America ◽  
Active Surveillance ◽  
Surveillance System ◽  
Influenza A ◽  
Virus Infections ◽  
Influenza Like Illness ◽  
Epidemiological Features ◽  
Influenza A H1n1 ◽  
Set Up

In response to the ongoing influenza A(H1N1)v pandemic, first detected in North America in April 2009, Belgium has set up an active surveillance system for influenza-like illness among travellers returning from affected areas. This communication describes the clinical and epidemiological features of the first 43 laboratory-confirmed cases in Belgium.

scholarly journals Pandemic-related health behavior: repeat episodes of influenza-like illness related to the 2009 H1N1 influenza pandemic

2017 ◽  
Vol 145 (12) ◽  
pp. 2611-2617 ◽  
Author(s):  
O. MGBERE ◽  
K. NGO ◽  
S. KHUWAJA ◽  
M. MOUZOON ◽  
A. GREISINGER ◽  
...  
Keyword(s):  
Influenza A ◽  
Influenza Pandemic ◽  
Age Groups ◽  
Future Research ◽  
Surveillance Program ◽  
Care Seeking ◽  
Influenza Like Illness ◽  
Influenza A H1n1 ◽  
Data Source ◽  
Return Visits

SUMMARYThe Houston Health Department (HHD) in Texas tracks influenza-like illness (ILI) in the community through its Influenza Sentinel Surveillance Program, which began in 2008. After the influenza A(H1N1) pandemic (pH1N1) in 2009, investigators sought to assess the feasibility of this program as a non-traditional data source for tracking and monitoring care-seeking activities. Through the process of characterizing and describing patients who had ‘return visits’, or who were considered the heaviest ILI-related care-utilizers, the investigators sought to understand the strengths and limitations of this data source. Data used for this study were obtained from a multispecialty clinic in Houston, Texas between August 2008 and January 2011 across three phases: pre-pH1N1, pH1N1, and post-pH1N1. The data, which comprised of 4047 patient visits, yielded 150 return visits. We found an increase in the number of visits for ILI and proportion of return visits during the pandemic phase (pH1N1), as well as differences in the likelihood of a return visit between genders and age groups. More broadly, the findings of this study provide important considerations for future research and expose important gaps in using surveillance data to assess sick-role behaviors.

scholarly journals A Bayesian Inferential Approach to Quantify the Transmission Intensity of Disease Outbreak

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Adiveppa S. Kadi ◽  
Shivakumari R. Avaradi
Keyword(s):  
Basic Reproduction Number ◽  
Influenza A ◽  
Reproduction Number ◽  
Influenza Pandemic ◽  
Credible Interval ◽  
Disease Outbreak ◽  
Mitigation Strategies ◽  
Incidence Data ◽  
Health Authorities ◽  
Influenza A H1n1

Background. Emergence of infectious diseases like influenza pandemic (H1N1) 2009 has become great concern, which posed new challenges to the health authorities worldwide. To control these diseases various studies have been developed in the field of mathematical modelling, which is useful tool for understanding the epidemiological dynamics and their dependence on social mixing patterns.Method. We have used Bayesian approach to quantify the disease outbreak through key epidemiological parameter basic reproduction number (R0), using effective contacts, defined as sum of the product of incidence cases and probability of generation time distribution. We have estimatedR0from daily case incidence data for pandemic influenza A/H1N1 2009 in India, for the initial phase.Result. The estimatedR0with 95% credible interval is consistent with several other studies on the same strain. Through sensitivity analysis our study indicates that infectiousness affects the estimate ofR0.Conclusion. Basic reproduction numberR0provides the useful information to the public health system to do some effort in controlling the disease by using mitigation strategies like vaccination, quarantine, and so forth.

scholarly journals 2009 pandemic influenza A(H1N1) outbreak in a complex of schools in Paris, France, June 2009

2010 ◽  
Vol 15 (25) ◽  
Author(s):  
P Carrillo-Santisteve ◽  
S Renard-Dubois ◽  
G Cheron ◽  
M Csaszar-Goutchkoff ◽  
M Lecuit ◽  
...  
Keyword(s):  
Outpatient Clinic ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Index Case ◽  
School Closure ◽  
Control Measures ◽  
The United Kingdom ◽  
Influenza A H1n1 ◽  
Community Transmission ◽  
H1n1 Outbreak

An outbreak of 2009 pandemic influenza A(H1N1), involving 81 cases with symptoms of influenza-like illness, was confirmed in June 2009 in a complex of schools in Paris, France. At that time, there was no community transmission in France. The index case, a 10-year-old girl, had travelled to the United Kingdom with her school class. Of the 81 symptomatic cases, 35 were confirmed and 46 were probable; 48 of the cases were female. Three were adults and 78 were children (median age of the children was 7.9 years, range: 6 months to 12 years). Control measures were implemented as soon as a new case was confirmed in a school, which included active case finding among the pupils in the same class as the index case, setting up a dedicated influenza outpatient clinic that families were recommended to consult if necessary, prophylactic treatment of contacts and school closure. A retrospective study was conducted on all confirmed cases and all symptomatic cases who had consulted the dedicated outpatient clinic from 17 to 27 June 2009. Further work is needed to better define conditions under which the pandemic virus can be transmitted in schools and in households.

scholarly journals Preparedness for the prevention and control of influenza outbreaks on passenger ships in the EU: the SHIPSAN TRAINET project communication

2009 ◽  
Vol 14 (21) ◽  
Author(s):  
V A Mouchtouri ◽  
N Black ◽  
G Nichols ◽  
T Paux ◽  
T Riemer ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Influenza A ◽  
Control Measures ◽  
Policies And Procedures ◽  
Influenza A H1n1 ◽  
Passenger Ships ◽  
Rapid Spread ◽  
Influenza Outbreaks ◽  
And Control ◽  
The Eu

Passenger ships carry a large number of people in confined spaces. A case of the new influenza A (H1N1) virus aboard a passenger ship is an expected event and would lead to rapid spread of the virus, if preventive measures are not in place. However, many cruise lines have detailed policies and procedures to deal with cases of influenza like illness (ILI). The EU SHIPSAN and SHIPSAN TRAINET projects include in their objectives guidelines for the prevention and control of communicable diseases aboard passenger ships. A literature review showed that from 1997 to 2005, nine confirmed outbreaks of influenza were linked to passenger ships, with attack rates up to 37%. It is important to establish and maintain a surveillance system for ILI aboard passenger ships, in order to systematically collect data that can help to determine the baseline illness levels. Monitoring these will enable early identification of outbreaks and allow timely implementation of control measures.

scholarly journals Ratio of Excess ED ILI Visits to Seroprevalence, Influenza A/H1N1 Infection, FL, 2009

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Richard Hopkins ◽  
Aaron Kite-Powell ◽  
Kate Goodin ◽  
Janet J. Hamilton
Keyword(s):  
Emergency Department ◽  
Emergency Department Visit ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Influenza Pandemic ◽  
H1n1 Infection ◽  
Influenza Like Illness ◽  
Influenza A H1n1 ◽  
2009 Influenza Pandemic

During the 2009 influenza pandemic, due to the 2009 pandemic influenza A (pH1N1) virus, there were an estimated 44 infections for every excess emergency department visit for influenza-like illness in Florida.

scholarly journals Electronic real-time surveillance for influenza-like illness: experience from the 2009 influenza A(H1N1) pandemic in Denmark

2011 ◽  
Vol 16 (3) ◽  
Author(s):  
K M Harder ◽  
P H Andersen ◽  
I Bæhr ◽  
L P Nielsen ◽  
S Ethelberg ◽  
...  
Keyword(s):  
Real Time ◽  
Surveillance System ◽  
Influenza A ◽  
Daily Basis ◽  
Influenza Surveillance ◽  
Situational Analysis ◽  
Influenza Like Illness ◽  
Electronic Reporting ◽  
Influenza A H1n1 ◽  
Sentinel Surveillance System

To enhance surveillance for influenza-like illness (ILI) in Denmark, a year-round electronic reporting system was established in collaboration with the Danish medical on-call service (DMOS). In order to achieve real-time surveillance of ILI, a checkbox for ILI was inserted in the electronic health record and a system for daily transfer of data to the national surveillance centre was implemented. The weekly number of all consultations in DMOS was around 60,000, and activity of ILI peaked in week 46 of 2009 when 9.5% of 73,723 consultations were classified as ILI. The incidence of ILI reached a maximum on 16 November 2009 for individuals between five and 24 years of age, followed by peaks in children under five years, adults aged between 25 and 64 years and on 27 November in senior citizens (65 years old or older). In addition to the established influenza surveillance system, this novel system was useful because it was timelier than the sentinel surveillance system and allowed for a detailed situational analysis including subgroup analysis on a daily basis.

scholarly journals Heterogeneity in transmissibility and shedding SARS-CoV-2 via droplets and aerosols

2020 ◽  
Author(s):  
Paul Z. Chen ◽  
Niklas Bobrovitz ◽  
Zahra Premji ◽  
Marion Koopmans ◽  
David N. Fisman ◽  
...  
Keyword(s):  
Disease Control ◽  
Influenza A ◽  
Close Contact ◽  
Influenza Pandemic ◽  
Control Measures ◽  
Transmission Risk ◽  
Contact Tracing ◽  
Infectious Period ◽  
Influenza A H1n1 ◽  
Respiratory Droplets

AbstractWhich virological factors mediate overdispersion in the transmissibility of emerging viruses remains a longstanding question in infectious disease epidemiology. Here, we use systematic review to develop a comprehensive dataset of respiratory viral loads (rVLs) of SARS-CoV-2, SARS-CoV-1 and influenza A(H1N1)pdm09. We then comparatively meta-analyze the data and model individual infectiousness by shedding viable virus via respiratory droplets and aerosols. Our analyses indicate heterogeneity in rVL as an intrinsic virological factor facilitating greater overdispersion for SARS-CoV-2 in the COVID-19 pandemic than A(H1N1)pdm09 in the 2009 influenza pandemic. For COVID-19, case heterogeneity remains broad throughout the infectious period, including for pediatric and asymptomatic infections. Hence, many COVID-19 cases inherently present minimal transmission risk, whereas highly infectious individuals shed tens to thousands of SARS-CoV-2 virions/min via droplets and aerosols while breathing, talking and singing. Coughing increases the contagiousness, especially in close contact, of symptomatic cases relative to asymptomatic ones. Infectiousness tends to be elevated between 1-5 days post-symptom onset. Our findings show how individual case variations influence virus transmissibility and present considerations for disease control in the COVID-19 pandemic.Significance StatementFor some emerging infectious diseases, including COVID-19, few cases cause most secondary infections. Others, like influenza A(H1N1)pdm09, spread more homogenously. The virological factors that mediate such distinctions in transmissibility remain unelucidated, prohibiting the development of specific disease control measures. We find that intrinsic case variation in respiratory viral load (rVL) facilitates overdispersion, and superspreading, for COVID-19 but more homogeneous transmission for A(H1N1)pdm09. We interpret the influence of heterogeneity in rVL on individual infectiousness by modelling likelihoods of shedding viable virus via respiratory droplets and aerosols. We analyze the distribution and kinetics of SARS-CoV-2 rVL, including across age and symptomatology subgroups. Our findings compare individual infectiousness across COVID-19 and A(H1N1)pdm09 cases and present quantitative guidance on triaging COVID-19 contact tracing.

scholarly journals Optimal Control of an SIR Model with Delay in State and Control Variables

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mohamed Elhia ◽  
Mostafa Rachik ◽  
Elhabib Benlahmar
Keyword(s):  
Optimal Control ◽  
Influenza A ◽  
Optimization Strategy ◽  
Sir Epidemic Model ◽  
Optimal Control Strategy ◽  
Control Variables ◽  
Sir Epidemic ◽  
Influenza A H1n1 ◽  
Using Data ◽  
And Control

We will investigate the optimal control strategy of an SIR epidemic model with time delay in state and control variables. We use a vaccination program to minimize the number of susceptible and infected individuals and to maximize the number of recovered individuals. Existence for the optimal control is established; Pontryagin’s maximum principle is used to characterize this optimal control, and the optimality system is solved by a discretization method based on the forward and backward difference approximations. The numerical simulation is carried out using data regarding the course of influenza A (H1N1) in Morocco. The obtained results confirm the performance of the optimization strategy.

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