scholarly journals Epidemiological Analysis of the 2019 Dengue Epidemic in Bhutan

2021 ◽  
Vol 18 (1) ◽  
pp. 354
Author(s):  
Tsheten Tsheten ◽  
Angus Mclure ◽  
Archie C. A. Clements ◽  
Darren J. Gray ◽  
Tenzin Wangdi ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Monsoon Season ◽  
Outbreak Response ◽  
Spatial And Temporal Patterns ◽  
Epidemiological Analysis ◽  
Preparedness Plan ◽  
Epidemic Period ◽  
Timely Response ◽  
National Preparedness ◽  
Dengue Epidemic

Bhutan experienced its largest and first nation-wide dengue epidemic in 2019. The cases in 2019 were greater than the total number of cases in all the previous years. This study aimed to characterize the spatiotemporal patterns and effective reproduction number of this explosive epidemic. Weekly notified dengue cases were extracted from the National Early Warning, Alert, Response and Surveillance (NEWARS) database to describe the spatial and temporal patterns of the epidemic. The time-varying, temperature-adjusted cohort effective reproduction number was estimated over the course of the epidemic. The dengue epidemic occurred between 29 April and 8 December 2019 over 32 weeks, and included 5935 cases. During the epidemic, dengue expanded from six to 44 subdistricts. The effective reproduction number was <3 for most of the epidemic period, except for a ≈1 month period of explosive growth, coinciding with the monsoon season and school vacations, when the effective reproduction number peaked >30 and after which the effective reproduction number declined steadily. Interventions were only initiated 6 weeks after the end of the period of explosive growth. This finding highlights the need to reinforce the national preparedness plan for outbreak response, and to enable the early detection of cases and timely response.

scholarly journals Health preparedness plan to prevent dengue epidemic in an urban area of Delhi

2020 ◽  
Vol 101 ◽  
pp. 270-271
Author(s):  
P. Goel ◽  
M.M. Singh ◽  
A.L. Borle ◽  
S. Garg
Keyword(s):  
Urban Area ◽  
Preparedness Plan ◽  
Dengue Epidemic

scholarly journals Estimating the transmission advantage of the D614G mutant strain of SARS-CoV-2, December 2019 to June 2020

2021 ◽  
Vol 26 (49) ◽  
Author(s):  
Kathy Leung ◽  
Yao Pei ◽  
Gabriel M Leung ◽  
Tommy TY Lam ◽  
Joseph T Wu
Keyword(s):  
Amino Acid ◽  
Amino Acid Change ◽  
Reproduction Number ◽  
Sequence Data ◽  
Credible Interval ◽  
Epidemiological Analysis ◽  
Rapid Spread ◽  
Mutant Strains ◽  
Virus Strains ◽  
The Basic Reproduction Number

Introduction The SARS-CoV-2 lineages carrying the amino acid change D614G have become the dominant variants in the global COVID-19 pandemic. By June 2021, all the emerging variants of concern carried the D614G mutation. The rapid spread of the G614 mutant suggests that it may have a transmission advantage over the D614 wildtype. Aim Our objective was to estimate the transmission advantage of D614G by integrating phylogenetic and epidemiological analysis. Methods We assume that the mutation D614G was the only site of interest which characterised the two cocirculating virus strains by June 2020, but their differential transmissibility might be attributable to a combination of D614G and other mutations. We define the fitness of G614 as the ratio of the basic reproduction number of the strain with G614 to the strain with D614 and applied an epidemiological framework for fitness inference to analyse SARS-CoV-2 surveillance and sequence data. Results Using this framework, we estimated that the G614 mutant is 31% (95% credible interval: 28–34) more transmissible than the D614 wildtype. Therefore, interventions that were previously effective in containing or mitigating the D614 wildtype (e.g. in China, Vietnam and Thailand) may be less effective against the G614 mutant. Conclusion Our framework can be readily integrated into current SARS-CoV-2 surveillance to monitor the emergence and fitness of mutant strains such that pandemic surveillance, disease control and development of treatment and vaccines can be adjusted dynamically.

scholarly journals The seasonal reproduction number of dengue fever impacts of climate on transmission

2016 ◽  
Author(s):  
Sittisede Polwiang
Keyword(s):  
Low Temperature ◽  
Dengue Fever ◽  
Rainy Season ◽  
Reproduction Number ◽  
Dengue Infection ◽  
Viral Disease ◽  
Seasonal Reproduction ◽  
Epidemic Period ◽  
Very High ◽  
Very Low Temperature

Background: The dengue fever is a mosquito-borne viral disease and a regular epidemic in Thailand. The peak of the dengue epidemic period is around June to August during the rainy season. It is believed that the climate is an important factor for dengue transmission.Method: A mathematical model for vector-host infectious disease was used to calculate the impacts of climate to the transmission of dengue virus. In this study, the data of climate and dengue fever cases were derived from Chiang Mai during 2008-2015, Thailand. The value of seasonal reproduction number was calculated to evaluate the potential, severity and persistence of dengue infection.Results: The mosquito population was increasing exponentially from the start of the rainy season in early May and reached its the peak in late June. The simulations suggest that the greatest potential for the dengue transmission occurs when the temperature is 28.9ºC. The seasonal reproduction numbers were larger than one from late March to end of August and reaching the peak in June. The highest incidences occurred in August due to the delay of transmission humans-mosquito-humans. Increasing mean temperature by 1.2ºC, the number of incidences increases 43.7%. However, a very high or very low temperature reduces the number of infection.Discussion and Conclusion: The results show that the dengue infection depends on the seasonal variation of the climate. The rainfall provides places for the mosquitoes to lay eggs and develop to adult stage. The temperature plays an important role in the life cycle and behavior of the mosquitoes. A very high or very low temperature reduces the risk of the dengue infection.

scholarly journals Dengue and the risk of urban yellow fever reintroduction in São Paulo State, Brazil

2003 ◽  
Vol 37 (4) ◽  
pp. 477-484 ◽  
Author(s):  
Eduardo Massad ◽  
Marcelo Nascimento Burattini ◽  
Francisco Antonio Bezerra Coutinho ◽  
Luiz Fernandes Lopez
Keyword(s):  
Aedes Aegypti ◽  
Yellow Fever ◽  
Reproduction Number ◽  
Sao Paulo ◽  
São Paulo ◽  
Infested Area ◽  
Paulo State ◽  
Extrinsic Incubation Period ◽  
Epidemiological Situation ◽  
Dengue Epidemic

OBJECTIVE: To propose a mathematical method for the estimation of the Basic Reproduction Number, R0, of urban yellow fever in a dengue-infested area. METHODS: The method is based on the assumption that, as the same vector (Aedes aegypti) causes both infections, all the quantities related to the mosquito, estimated from the initial phase of dengue epidemic, could be applied to yellow fever dynamics. It is demonstrated that R0 for yellow fever is, on average, 43% lower than that for dengue. This difference is due to the longer dengue viremia and its shorter extrinsic incubation period. RESULTS: In this study the analysis was expanded to the epidemiological situation of dengue in São Paulo in the year 2001. The total number of dengue cases increased from 3,582 in 2000 to 51,348 in 2001. It was then calculated R0 for yellow fever for every city which have shown R0 of dengue greater than 1. It was also estimated the total number of unprotected people living in highly risky areas for urban yellow fever. CONCLUSIONS: Currently there is a great number of non-vaccinated people living in Aedes aegypti infested area in the state of São Paulo.

scholarly journals Dynamics Analysis of an Epidemiological Model with Media Impact and Two Delays

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Lianwen Wang ◽  
Yong Li ◽  
Liuyong Pang
Keyword(s):  
Reproduction Number ◽  
Threshold Dynamics ◽  
Global Dynamics ◽  
Lyapunov Functionals ◽  
Dynamics Analysis ◽  
Epidemic Spread ◽  
Media Impact ◽  
Timely Response ◽  
Two Delays ◽  
The Impact

This paper is concerned with exploring the global dynamics of SEIR epidemic model with media impact, which incorporates latency and relapse delays. The permanence of the model is carefully discussed. By suitable Lyapunov functionals, we establish the global stability of the equilibria. It is found that the basic reproduction number completely determines the threshold dynamics of the SEIR model. Finally, the impact of media on the epidemic spread is studied, which reveals that timely response of media and individuals may play a more key role in disease control.

scholarly journals Multiple Virus Lineages Sharing Recent Common Ancestry Were Associated with a Large Rift Valley Fever Outbreak among Livestock in Kenya during 2006-2007

2008 ◽  
Vol 82 (22) ◽  
pp. 11152-11166 ◽  
Author(s):  
Brian H. Bird ◽  
Jane W. K. Githinji ◽  
Joseph M. Macharia ◽  
Jacqueline L. Kasiiti ◽  
Rees M. Muriithi ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Gene Segment ◽  
Genomic Diversity ◽  
Common Ancestry ◽  
Outbreak Response ◽  
Valley Fever ◽  
Virus Activity ◽  
Epidemic Period ◽  
Multiple Virus

ABSTRACT Rift Valley fever (RVF) virus historically has caused widespread and extensive outbreaks of severe human and livestock disease throughout Africa, Madagascar, and the Arabian Peninsula. Following unusually heavy rainfall during the late autumn of 2006, reports of human and animal illness consistent with RVF virus infection emerged across semiarid regions of the Garissa District of northeastern Kenya and southern Somalia. Following initial RVF virus laboratory confirmation, a high-throughput RVF diagnostic facility was established at the Kenyan Central Veterinary Laboratories in Kabete, Kenya, to support the real-time identification of infected livestock and to facilitate outbreak response and control activities. A total of 3,250 specimens from a variety of animal species, including domesticated livestock (cattle, sheep, goats, and camels) and wildlife collected from a total of 55 of 71 Kenyan administrative districts, were tested by molecular and serologic assays. Evidence of RVF infection was found in 9.2% of animals tested and across 23 districts of Kenya, reflecting the large number of affected livestock and the geographic extent of the outbreak. The complete S, M, and/or L genome segment sequence was obtained from a total of 31 RVF virus specimens spanning the entire known outbreak period (December-May) and geographic areas affected by RVF virus activity. Extensive genomic analyses demonstrated the concurrent circulation of multiple virus lineages, gene segment reassortment, and the common ancestry of the 2006/2007 outbreak viruses with those from the 1997-1998 east African RVF outbreak. Evidence of recent increases in genomic diversity and effective population size 2 to 4 years prior to the 2006-2007 outbreak also was found, indicating ongoing RVF virus activity and evolution during the interepizootic/epidemic period. These findings have implications for further studies of basic RVF virus ecology and the design of future surveillance/diagnostic activities, and they highlight the critical need for safe and effective vaccines and antiviral compounds to combat this significant veterinary and public health threat.

scholarly journals Novel Coronavirus in Nigeria: Epidemiological analysis of the first 45 days of the pandemic

2020 ◽  
Author(s):  
Oyelola A. Adegboye ◽  
Adeshina I. Adekunle ◽  
Ezra Gayawan
Keyword(s):  
Doubling Time ◽  
Reproduction Number ◽  
Infected Individual ◽  
World Health ◽  
Time Interval ◽  
Epidemiological Analysis ◽  
Serial Interval ◽  
Novel Coronavirus ◽  
Health Organization ◽  
Local Transmission

AbstractBackgroundOn December 31, 2019, the World Health Organization (WHO) was notified of a novel coronavirus in China that was later named COVID-19. On March 11, 2020, the outbreak of COVID-19 was declared a pandemic. The first instance of the virus in Nigeria was documented on February 27, 2020.MethodsThis study provides a preliminary epidemiological analysis of the first 45 days of COVID-19 outbreak in Nigeria quantifying. We estimated the early transmissibility via time-varying reproduction number based on Bayesian method that incorporates uncertainty in the distribution of serial interval (time interval between symptoms onset in an infected individual and the infector) and adjusted for disease importation.FindingsBy April 11, 2020, 318 confirmed cases and 10 deaths from COVID-19 have occurred in Nigeria. At day 45, the exponential growth rate was 0.07 (95% Confidence Interval (CI): 0.05 – 0.10) with doubling time of 9.84 days (95% CI: 7.28 – 15.18). Separately for travel related and local cases the doubling time was 12.88 days and 2.86 days, respectively. Furthermore, we estimated the reproduction number for each day of the outbreak using three-weekly window while adjusting for travel related cases. The estimated reproduction number was 4.98 (95% CrI: 2.65 – 8.41) at day 22 (March 19, 2020), peaking at 5.61 (95% CrI: 3.83 –7.88) at day 25 (March 22, 2020). The median reproduction number over the study period was 2.71 and the latest value at April 11, 2020 was 1.42 (95% CI: 1.26 – 1.58).InterpretationThese 45-day estimates suggested that cases of COVID-19 in Nigeria have been remarkably lower than expected and the preparedness to detect needs to be shifted to stop local transmission.FundingNone

scholarly journals An early start of West Nile virus seasonal transmission: the added value of One Heath surveillance in detecting early circulation and triggering timely response in Italy, June to July 2018

2018 ◽  
Vol 23 (32) ◽  
Author(s):  
Flavia Riccardo ◽  
Federica Monaco ◽  
Antonino Bella ◽  
Giovanni Savini ◽  
Francesca Russo ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Virus Transmission ◽  
Human Case ◽  
Added Value ◽  
Surveillance Systems ◽  
West Nile ◽  
Health Authorities ◽  
West Nile Virus Transmission ◽  
Timely Response ◽  
National Preparedness

In Italy, the 2018 West Nile virus transmission season started early with a high number of cases reported. One-Health surveillance, within the Italian West Nile national preparedness and response plan, detected viral circulation 9 days before symptom-onset of the first confirmed human case; triggering timely implementation of blood and transplant safety measures. This is an example of how functional coordination allows health authorities to use early warning triggers from surveillance systems to implement preventive measures.

After Action Review Qualitative research on Yellow Fever outbreak Coordination, Surveillance & Reponses in Wolaita Zone of SNNPR Region, Ethiopia

2020 ◽  
Author(s):  
Yonas Assefa Tufa ◽  
Yaregal Fufa ◽  
Diriba Gemechu ◽  
Melaku Abebe ◽  
Shambel Habebe ◽  
...  
Keyword(s):  
Qualitative Research ◽  
Yellow Fever ◽  
Surveillance System ◽  
Lessons Learned ◽  
Research Approach ◽  
Outbreak Response ◽  
Preparedness Plan ◽  
Roles And Responsibilities ◽  
After Action Review ◽  
First Case

Abstract Background: Coordinating outbreak investigations requires effective interagency communication. Important tasks include making the initial notifications, establishing roles and responsibilities for each jurisdiction, providing updates on the progress of the investigations, revising priorities for the investigation, and establishing the next steps. The major goal of surveillance activities is to identify and eliminate preventable causes of morbidity and mortality. Outbreak response basically entails preparedness which helps to establish arrangements in advance to enable timely, effective and appropriate responses to specific potential hazardous events or emerging disaster situations that might threaten society/environment Objective: To review lessons learned from the October 2018 Wolayta Zone yellow fever outbreak management in SNNPR, Ethiopia. Methods: Qualitative research approach, with Thematic Analysis. Purposive sampling method was used. Data were collected through FGDs, in-depth interviews, observation and document reviews Results : Among the main findings of the review is the weakness of the surveillance to detect case; the surveillance system was not that much effective for early detection of viral hemorrhagic fevers and there was knowledge gap to detect in the existing. The Review found out further that preparedness plan was weak, failing to consider the outbreak for VRAM. However, it is worth-noting that the Review showed that despite late detection, a rapid response team was set up and was able to save the lives of many during the outbreak. The findings further showed there was good coordination among various stakeholders at different levels and with satisfying sharing of roles and responsibilities. Conclusion: Based on the major findings, it may be concluded that the surveillance system was weak to detect yellow fever outbreak occurrence in Wolaita Zone. A major gap is therefore the inability to include the case to the IDSR weekly report. Once the case was confirmed, the response to the crisis was fairly commendable. Even though there was a confusion on identifying the first case, after the confirmation of the first case, the case management went as per the standard guideline and SOPs, helping save so many lives through availing the service free of charge Key terms: After Action Review; Outbreak Response; Yellow Fever, Surveillance, Coordination,

Sign in / Sign up

Export Citation Format

Share Document