scholarly journals Spatial and temporal invasion dynamics of the 2014–2017 Zika and chikungunya epidemics in Colombia

2021 ◽  
Vol 17 (7) ◽  
pp. e1009174
Author(s):  
Kelly Charniga ◽  
Zulma M. Cucunubá ◽  
Marcela Mercado ◽  
Franklyn Prieto ◽  
Martha Ospina ◽  
...  
Keyword(s):  
Zika Virus ◽  
Temporal Dynamics ◽  
Virus Disease ◽  
Geographic Distance ◽  
Geographic Origin ◽  
Gravity Models ◽  
Long Distance ◽  
Spatial Spread ◽  
Invasion Dynamics ◽  
Logistic Regression Models

Zika virus (ZIKV) and chikungunya virus (CHIKV) were recently introduced into the Americas resulting in significant disease burdens. Understanding their spatial and temporal dynamics at the subnational level is key to informing surveillance and preparedness for future epidemics. We analyzed anonymized line list data on approximately 105,000 Zika virus disease and 412,000 chikungunya fever suspected and laboratory-confirmed cases during the 2014–2017 epidemics. We first determined the week of invasion in each city. Out of 1,122, 288 cities met criteria for epidemic invasion by ZIKA and 338 cities by CHIKV. We analyzed risk factors for invasion using linear and logistic regression models. We also estimated that the geographic origin of both epidemics was located in Barranquilla, north Colombia. We assessed the spatial and temporal invasion dynamics of both viruses to analyze transmission between cities using a suite of (i) gravity models, (ii) Stouffer’s rank models, and (iii) radiation models with two types of distance metrics, geographic distance and travel time between cities. Invasion risk was best captured by a gravity model when accounting for geographic distance and intermediate levels of density dependence; Stouffer’s rank model with geographic distance performed similarly well. Although a few long-distance invasion events occurred at the beginning of the epidemics, an estimated distance power of 1.7 (95% CrI: 1.5–2.0) from the gravity models suggests that spatial spread was primarily driven by short-distance transmission. Similarities between the epidemics were highlighted by jointly fitted models, which were preferred over individual models when the transmission intensity was allowed to vary across arboviruses. However, ZIKV spread considerably faster than CHIKV.

scholarly journals Spatial and temporal invasion dynamics of the 2014-2017 Zika and chikungunya epidemics in Colombia

2020 ◽  
Author(s):  
Kelly Charniga ◽  
Zulma M Cucunubá ◽  
Marcela Mercado ◽  
Franklyn Prieto ◽  
Martha Ospina ◽  
...  
Keyword(s):  
Zika Virus ◽  
Temporal Dynamics ◽  
Virus Disease ◽  
Geographic Distance ◽  
Geographic Origin ◽  
Gravity Models ◽  
Long Distance ◽  
Spatial Spread ◽  
Invasion Dynamics ◽  
Large Populations

Zika virus (ZIKV) and chikungunya virus (CHIKV) were recently introduced into the Americas resulting in significant disease burdens. Understanding their spatial and temporal dynamics at the subnational level is key to informing surveillance and preparedness for future epidemics. We analyzed anonymized line list data on approximately 105,000 Zika virus disease and 412,000 chikungunya fever suspected and laboratory-confirmed cases during the 2014-2017 epidemics. We first determined the week of invasion in each city. Out of 1,122, 288 cities met criteria for epidemic invasion by ZIKA and 338 cities by CHIKV. We estimated that the geographic origin of both epidemics was located in Barranquilla, north Colombia. Using gravity models, we assessed the spatial and temporal invasion dynamics of both viruses to analyze transmission between cities. Invasion risk was best captured when accounting for geographic distance and intermediate levels of density dependence. Although a few long-distance invasion events occurred at the beginning of the epidemics, an estimated distance power of 1.7 (95% CrI: 1.5-2.0) suggests that spatial spread was primarily driven by short-distance transmission. Cities with large populations were more likely to spread disease than cities with smaller populations. Similarities between the epidemics included having the same estimated geographic origin and having the same five parameters estimated in the best-fitting models. ZIKV spread considerably faster than CHIKV.

scholarly journals Deploying dengue-suppressing Wolbachia: robust models predict slow but effective spatial spread in Aedes aegypti

2016 ◽  
Author(s):  
Michael Turelli ◽  
Nicholas H. Barton
Keyword(s):  
Aedes Aegypti ◽  
Temporal Dynamics ◽  
Target Area ◽  
Long Distance ◽  
Frequency Dependent ◽  
Spatial Spread ◽  
Frequency Independent ◽  
Dispersal Distances ◽  
Novel Strategy ◽  
Non Gaussian

AbstractA novel strategy for controlling the spread of arboviral diseases such as dengue, Zika and chikungunya is to transform mosquito populations with virus-suppressing Wolbaehia. In general, Wolbachia transinfected into mosquitoes induce fitness costs through lower viability or fecundity. These maternally inherited bacteria also produce a frequency-dependent advantage for infected females by inducing cytoplasmic incompatibility (CI), which kills the embryos produced by uninfected females mated to infected males. These competing effects, a frequency-dependent advantage and frequency-independent costs, produce bistable Wolbachia frequency dynamics. Above a threshold frequency, denoted p̂, CI drives fitness-decreasing Wolbachia transinfections through local populations; but below p̂, infection frequencies tend to decline to zero. If p̂ is not too high, CI also drives spatial spread once infections become established over sufficiently large areas. We illustrate how simple models provide testable predictions concerning the spatial and temporal dynamics of Wolbachia introductions, focusing on rate of spatial spread, the shape of spreading waves, and the conditions for initiating spread from local introductions. First, we consider the robustness of diffusion-based predictions to incorporating two important features of wMel-Aedes aegypti biology that may be inconsistent with the diffusion approximations, namely fast local dynamics induced by complete CI (i.e., all embryos produced from incompatible crosses die) and long-tailed, non-Gaussian dispersal. With complete CI, our numerical analyses show that long-tailed dispersal changes wave-width predictions only slightly; but it can significantly reduce wave speed relative to the diffusion prediction; it also allows smaller local introductions to initiate spatial spread. Second, we use approximations for p̂ and dispersal distances to predict the outcome of 2013 releases of wMel-infected Aedes aegypti in Cairns, Australia, Third, we describe new data from Aedes aegypti populations near Cairns, Australia that demonstrate long-distance dispersal and provide an approximate lower bound on p̂ for wMel in northeastern Australia. Finally, we apply our analyses to produce operational guidelines for efficient transformation of vector populations over large areas. We demonstrate that even very slow spatial spread, on the order of 10-20 m/month (as predicted), can produce area-wide population transformation within a few years following initial releases covering about 20-30% of the target area.

Estimating Contraceptive Needs and Increasing Access to Contraception in Response to the Zika Virus Disease Outbreak — Puerto Rico, 2016

2016 ◽  
Vol 65 (12) ◽  
Author(s):  
Naomi K. Tepper ◽  
Howard I. Goldberg ◽  
Manuel I. Vargas Bernal ◽  
Brenda Rivera ◽  
Meghan T. Frey ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Zika Virus ◽  
Virus Disease ◽  
Disease Outbreak ◽  
Access To Contraception

Spatial-temporal transmission dynamics and control of infectious diseases: Ebola virus disease (EVD) as a case study

2018 ◽  
Author(s):  
Cécile Viboud ◽  
Hélène Broutin ◽  
Gerardo Chowell
Keyword(s):  
Infectious Diseases ◽  
Disease Transmission ◽  
Ebola Virus ◽  
Temporal Dynamics ◽  
Virus Disease ◽  
Spatial Dynamics ◽  
Childhood Diseases ◽  
Middle Income ◽  
Theoretical Concepts ◽  
Dynamics And Control

Disentangling the spatial-temporal dynamics of infectious disease transmission is important to address issues of disease persistence, epidemic growth and optimal control. In this chapter, we review key concepts relating to the spatial-temporal dynamics of infectious diseases in meta-populations, whereby geographically separate subpopulations are connected by migration or mobility rates. We review the dynamics of colonization, persistence and extinction of emerging and recurrent pathogens in meta-populations; the role of demographic and environmental factors; and geographic heterogeneity in epidemic growth rate. We illustrate theoretical concepts by reviewing the spatial dynamics of childhood diseases and other acute infections in low- and middle-income countries, and provide a detailed description of the spatial-temporal dynamics of the 2014–16 Ebola epidemic in West Africa. We further discuss how increased availability of empirical data and recent methodological developments provide a deeper mechanistic understanding of transmission processes in space and time, and make recommendations for future work.

scholarly journals Threshold Dynamics in a Model for Zika Virus Disease with Seasonality

2021 ◽  
Vol 83 (4) ◽  
Author(s):  
Mahmoud A. Ibrahim ◽  
Attila Dénes
Keyword(s):  
Zika Virus ◽  
Reproduction Number ◽  
Virus Disease ◽  
Threshold Dynamics ◽  
Global Dynamics ◽  
Threshold Parameter ◽  
Globally Asymptotically Stable ◽  
Linear Integral ◽  
The Impact ◽  
Disease Free

AbstractWe present a compartmental population model for the spread of Zika virus disease including sexual and vectorial transmission as well as asymptomatic carriers. We apply a non-autonomous model with time-dependent mosquito birth, death and biting rates to integrate the impact of the periodicity of weather on the spread of Zika. We define the basic reproduction number $${\mathscr {R}}_{0}$$ R 0 as the spectral radius of a linear integral operator and show that the global dynamics is determined by this threshold parameter: If $${\mathscr {R}}_0 < 1,$$ R 0 < 1 , then the disease-free periodic solution is globally asymptotically stable, while if $${\mathscr {R}}_0 > 1,$$ R 0 > 1 , then the disease persists. We show numerical examples to study what kind of parameter changes might lead to a periodic recurrence of Zika.

scholarly journals Zika Virus: A Clinical Review

KYAMC Journal ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 719-725
Author(s):  
Md Daharul Islam ◽  
SM Tajdit Rahman ◽  
Khaleda Akhter ◽  
Md Azizul Hoque ◽  
Anannya Roy ◽  
...  
Keyword(s):  
Yellow Fever ◽  
Zika Virus ◽  
Yellow Fever Virus ◽  
Virus Disease ◽  
Specific Treatment ◽  
Abrupt Onset ◽  
Fever Virus ◽  
Control Measures ◽  
Disease Treatment ◽  
Antibodies Detection

Zika virus is a flavivirus related to Dengue virus, yellow fever virus and West Nile virus. It is considered an emerging arbovirus transmitted by mosquito of the genus Aedes. Its first description took place in 1947 in the Zika Forest in Uganda, isolated on Rhesus monkey used as bait to study the yellow fever virus. Clinical picture is characterized as a 'dengue-like' syndrome, with abrupt onset of fever; and an early onset of evanescent rash, often pruritic. Occasionally the disease has been associated with Guillain-Barré syndrome. The diagnosis can be performed by PCR or by IgG and IgM antibodies detection. No specific treatment or vaccine is available for Zika virus disease. Treatment is generally supportive. Control measures are same for dengue and chikungunya based mostly on health education and vector control.KYAMC Journal Vol. 7, No.-1, Jul 2016, Page 719-725

scholarly journals Genetic structure and dispersal patterns of the invasive psocid Liposcelis decolor (Pearman) in Australian grain storage systems

2010 ◽  
Vol 100 (5) ◽  
pp. 521-527 ◽  
Author(s):  
K.M. Mikac ◽  
N.N. FitzSimmons
Keyword(s):  
Genetic Structure ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Allelic Diversity ◽  
Mantel Test ◽  
Null Alleles ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Population Comparisons ◽  
Low Levels

AbstractMicrosatellite markers were used to investigate the genetic structure among invasive L. decolor populations from Australia and a single international population from Kansas, USA to determine patterns of dispersal. Six variable microsatellites displayed an average of 2.5–4.2 alleles per locus per population. Observed (HO) heterozygosity ranged from 0.12–0.65 per locus within populations; but, in 13 of 36 tests, HO was less than expected. Despite low levels of allelic diversity, genetic structure estimated as θ was significant for all pairwise comparisons between populations (θ=0.05–0.23). Due to suspected null alleles at four loci, ENA (excluding null alleles) corrected FST estimates were calculated overall and for pairwise population comparisons. The ENA-corrected FST values (0.02–0.10) revealed significant overall genetic structure, but none of the pairwise values were significantly different from zero. A Mantel test of isolation by distance indicated no relationship between genetic structure and geographic distance among all populations (r2=0.12, P=0.18) and for Australian populations only (r2=0.19, P=0.44), suggesting that IBD does not describe the pattern of gene flow among populations. This study supports a hypothesis of long distance dispersal by L. decolor at moderate to potentially high levels.

scholarly journals Dual burden of Zika and COVID-19 in India: challenges, opportunities and recommendations

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Mainak Bardhan ◽  
Debolina Pramanik ◽  
Rizana Riyaz ◽  
Mohammad Mehedi Hasan ◽  
Mohammad Yasir Essar
Keyword(s):  
Public Health ◽  
Early Diagnosis ◽  
Zika Virus ◽  
Virus Disease ◽  
Healthcare Resources ◽  
Health Measures ◽  
The World ◽  
Significant Public Health ◽  
Congenital Zika Syndrome ◽  
Dual Burden

AbstractThe COVID-19 pandemic has wreaked havoc in the world from last year, and any further insults like Zika virus will surely bring the apocalypse unto us. In July 2021, Zika began spreading in India, mainly in the state of Kerala. Zika infection resembles closely COVID-19 and other arboviral infections, which might lead to delayed and misdiagnosis, further leading to underreporting of cases. Some of the feared complications of Zika include Guillain–Barré syndrome and congenital Zika syndrome leading to microcephaly. Thus, Zika virus disease (ZVD) has significant public health and social impacts. Since the trifecta of infectious diseases (host, agent and environment) are all conducive to the spread of Zika in India, there is a huge risk that ZVD might become endemic in India, which is especially dangerous in the backdrop of this pandemic. This has to be stopped at all costs: the main aspects of which are public health measures, vector control and early diagnosis, especially in case of pregnant women. The diversion of healthcare resources for this pandemic has albeit made this difficult, but we must do our bit if we have to overcome this situation.

scholarly journals Zika virus disease

2017 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
AdelI Al-Afaleq
Keyword(s):  
Zika Virus ◽  
Virus Disease
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