Assessing the Risk of International Spread of Yellow Fever Virus: A Mathematical Analysis of an Urban Outbreak in Asunción, 2008

Johansson, Michael A.; Arana-Vizcarrondo, Neysarí; Biggerstaff, Brad J.; Gallagher, Nancy; Marano, Nina; Staples, J. Erin

doi:10.4269/ajtmh.2012.11-0432

Cited by 59 publications

(67 citation statements)

References 46 publications

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“…aegypti a muchos centros urbanos, pueda causar el resurgimiento de la fiebre amarilla urbana. Tal podría ser el caso de lo observado en Paraguay en 2008 (35).…”

Section: Significado En La Transmisión De Enfermedadesunclassified

Ecología de Aedes aegypti y Aedes albopictus en América y la transmisión de enfermedades

Rey

Lounibos

2015

biomedica

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La reciente expansión geográfica del mosquito Aedes albopictus ha estado acompañada en algunos sitios por la disminución en la abundancia o por la eliminación local de Aedes aegypti, pero las dos especies aún coexisten en extensas regiones de América. En este trabajo se ofrece un resumen de los posibles mecanismos responsables de sus patrones de abundancia y desplazamiento, así como de su significado en cuanto a la transmisión de enfermedades. Entre los mecanismos observados, se encuentran la competencia por recursos, las diferencias en la capacidad para soportar la inanición, la competencia aparente a través de efectos diferenciales del parásito Ascogregarina taiwanensis, y la inhibición causada por larvas de Ae. albopictus en el desarrollo de los huevos de Ae. aegypti. Un mecanismo propuesto como promotor de la coexistencia de estas especies es la segregación en diferentes hábitats, lo que evita la competencia directa. Aedes aegypti predomina en áreas urbanas, Ae. albopictus en áreas rurales, y las dos especies coexisten en áreas periurbanas. Existen pruebas de que la distribución de Ae. aegypti y Ae. albopictus también puede verse afectada en ciertas áreas, por la distancia desde la costa. Otra posible causa de la rápida desaparición de Ae. aegypti es la interferencia reproductiva entre las dos especies. De acuerdo con esta hipótesis, los efectos asimétricos de los apareamientos entre especies favorecen a Ae. albopictus. Este tipo de interferencia reproductiva podría ser la causante de la eliminación de poblaciones simpátricas de las especies involucradas y de la rapidez con que Ae. aegypti ha desaparecido de muchos lugares en América luego de la invasión de Ae. albopictus. Palabras clave:Aedes, arbovirus, virus chikungunya, dengue, hábitat. doi: http://dx.doi.org/10.7705/biomedica.v35i2.2514 Ecology of Aedes aegypti and Aedes albopictus in the Americas and disease transmissionThe recent range expansion of the mosquito Aedes albopictus has been associated in some areas by declines in abundance or local elimination of Aedes aegypti, but the two species still coexist in large regions of the Americas. We offer a summary of the possible mechanisms responsible for the abundance and displacement pattern observed and of their significance in terms of disease transmission. Among these mechanisms we may mention the competition for limiting resources, the differences in the ability to withstand starvation, the apparent competition through differential effects of the parasite Ascogregarina taiwanensis, and the inhibition of Ae. aegypti egg development by Ae. albopictus larvae. Habitat segregation has been proposed as a mechanism promoting the coexistence of the two species through avoidance of direct competition. Aedes aegypti predominates in urban areas, Ae. albopictus in rural ones, and both species coexist in the suburbs. There is also evidence that in certain areas, habitat segregation in terms of distance from the coast can influence the distribution of both species. Another possible cause of the rapid disappearanc...

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“…aegypti a muchos centros urbanos, pueda causar el resurgimiento de la fiebre amarilla urbana. Tal podría ser el caso de lo observado en Paraguay en 2008 (35).…”

Section: Significado En La Transmisión De Enfermedadesunclassified

Ecología de Aedes aegypti y Aedes albopictus en América y la transmisión de enfermedades

Rey

Lounibos

2015

biomedica

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“…In the colon, thick mucus layers, composed of a dense inner mucus layer and a loose outer mucus layer, cover luminal surfaces of the epithelium. The majority of the gut microbiota are present in the outer mucus layer, and none are present in the dense inner mucus layer [13,14]. Inflammatory responses lead to a reduction in the number of goblet cells, reduced thickness of the mucus layer, and altered mucus composition [15,16].…”

Section: Introductionmentioning

confidence: 99%

Analysis of endoscopic brush samples identified mucosa-associated dysbiosis in inflammatory bowel disease

et al. 2017

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Background The mucosa-associated gut microbiota directly modulates epithelial and mucosal function. In this study, we investigated the mucosa-associated microbial community in patients with inflammatory bowel disease (IBD), using endoscopic brush samples. Methods A total of 174 mucus samples from 43 patients with ulcerative colitis (UC), 26 with Crohn's disease (CD) and 14 non-IBD controls were obtained by gentle brushing of mucosal surfaces using endoscopic cytology brushes. The gut microbiome was analyzed using 16S rRNA gene sequencing. Results There were no significant differences in microbial structure among different anatomical sites (the ileum, cecum and sigmoid colon) within individuals. There was, however, a significant difference in microbial structure between CD, UC and non-IBD controls. The difference between CD and non-IBD controls was more marked than that between UC patients and non-IBD controls. a-Diversity was significantly lower in UC and CD patients than non-IBD controls. When comparing CD patients with non-IBD controls, the phylum Proteobacteria was significantly increased and the phyla Firmicutes and Bacteroidetes were significantly reduced. These included a significant increase in the genera Escherichia, Ruminococcus (R. gnavus), Cetobacterium, Actinobacillus and Enterococcus, and a significant decrease in the genera Faecalibacterium, Coprococcus, Prevotella and Roseburia. Comparisons between CD and UC patients revealed a greater abundance of the genera Escherichia, Ruminococcus (R. gnavus), Clostridium, Cetobacterium, Peptostreptococcus in CD patients, and the genera Faecalibacterium, Blautia, Bifidobacterium, Roseburia and Citrobacter in UC patients. Conclusions Mucosa-associated dysbiosis was identified in IBD patients. CD and UC may be distinguishable from the mucosa-associated microbial community structure.

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“…Rates and routes of imported malaria have been shown to be significantly related to a combination of numbers of travellers to/from endemic destinations and the prevalence of malaria there [3]. The potential thus exists to construct a model based on global malaria prevalence [40,41], the local spatial interaction and accessibility to an airport within a region [60], transmission models for attack rate estimation [27], and traveller flow data [36], that can be used to forecast imported malaria rates, validated with imported malaria data reported by health facilities/organizations.…”

Section: Discussionmentioning

confidence: 99%

Global malaria connectivity through air travel

Huang

Tatem

2013

Malar J

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BackgroundAir travel has expanded at an unprecedented rate and continues to do so. Its effects have been seen on malaria in rates of imported cases, local outbreaks in non-endemic areas and the global spread of drug resistance. With elimination and global eradication back on the agenda, changing levels and compositions of imported malaria in malaria-free countries, and the threat of artemisinin resistance spreading from Southeast Asia, there is a need to better understand how the modern flow of air passengers connects each Plasmodium falciparum- and Plasmodium vivax-endemic region to the rest of the world.MethodsRecently constructed global P. falciparum and P.vivax malaria risk maps, along with data on flight schedules and modelled passenger flows across the air network, were combined to describe and quantify global malaria connectivity through air travel. Network analysis approaches were then utilized to describe and quantify the patterns that exist in passenger flows weighted by malaria prevalence. Finally, the connectivity within and to the Southeast Asia region where the threat of imported artemisinin resistance arising is highest, was examined to highlight risk routes for its spread.ResultsThe analyses demonstrate the substantial connectivity that now exists between and from malaria-endemic regions through air travel. While the air network provides connections to previously isolated malarious regions, it is clear that great variations exist, with significant regional communities of airports connected by higher rates of flow standing out. The structures of these communities are often not geographically coherent, with historical, economic and cultural ties evident, and variations between P. falciparum and P. vivax clear. Moreover, results highlight how well connected the malaria-endemic areas of Africa are now to Southeast Asia, illustrating the many possible routes that artemisinin-resistant strains could take.DiscussionThe continuing growth in air travel is playing an important role in the global epidemiology of malaria, with the endemic world becoming increasingly connected to both malaria-free areas and other endemic regions. The research presented here provides an initial effort to quantify and analyse the connectivity that exists across the malaria-endemic world through air travel, and provide a basic assessment of the risks it results in for movement of infections.

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Assessing the Risk of International Spread of Yellow Fever Virus: A Mathematical Analysis of an Urban Outbreak in Asunción, 2008

Cited by 59 publications

References 46 publications

Ecología de Aedes aegypti y Aedes albopictus en América y la transmisión de enfermedades

Ecología de Aedes aegypti y Aedes albopictus en América y la transmisión de enfermedades

Analysis of endoscopic brush samples identified mucosa-associated dysbiosis in inflammatory bowel disease

Global malaria connectivity through air travel

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