Yellow fever in Asia–a risk analysis

Abstract

Background There is concern about the risk of yellow fever (YF) establishment in Asia, owing to rising numbers of urban outbreaks in endemic countries and globalisation. Following an outbreak in Angola in 2016, YF cases were introduced into China. Prior to this, YF had never been recorded in Asia, despite climatic suitability and the presence of mosquitoes. An outbreak in Asia could result in widespread fatalities and huge economic impact. Therefore, quantifying the potential risk of YF outbreaks in Asia is a public health priority. Methods Using international flight data and YF incidence estimates from 2016, we quantified the risk of YF introduction via air travel into Asia. In locations with evidence of a competent mosquito population, the potential for autochthonous YF transmission was estimated using a temperature-dependent model of the reproduction number and a branching process model assuming a negative binomial distribution. Results 25 cities across Asia were estimated to be at risk of receiving at least one YF viraemic traveller during 2016. At their average temperatures, we estimated the probability of autochthonous transmission to be below 50% in all cities, which was primarily due to the limited number of estimated introductions that year. Conclusion Despite the rise in air travel, we found low support for travel patterns between YF endemic countries and Asia resulting in autochthonous transmission during 2016. This supports the historic absence of YF in Asia and suggests it could be due to a limited number of introductions in previous years. Future increases in travel volumes or YF incidence can increase the number of introductions and the risk of autochthonous transmission. Given the high proportion of asymptomatic or mild infections and the challenges of YF surveillance, our model can be used to estimate the introduction and outbreak risk, and can provide useful information to surveillance systems.

Live-attenuated YF17D-vectored COVID-19 vaccine protects from lethal yellow fever virus infection in mouse and hamster models

“… 5 Furthermore, increasing global travel bares the risk of YFV being imported into regions where the virus is historically absent, such as the Asia Pacific region, that harbors both dense populations of competent vector mosquitos and billions of immunologically naïve people, raising serious concerns of massive future epidemics. 6 , 7 A more sustainable YF17D vaccine supply and novel vaccines against YFV are needed. 8 …”

Dissecting the Species-Specific Virome in Culicoides of Thrace

“…Analyses of arthropod-borne viruses (arboviruses) have spurred the interest of the scientific community. Epidemics caused by yellow fever virus ( Cracknell Daniels et al, 2021 ), Zika virus ( Estévez-Herrera et al, 2021 ), dengue virus ( Mayer et al, 2017 ), West Nile virus ( Petersen, 2019 ), Rift Valley virus ( Gregor et al, 2021 ), chikungunya virus ( Mayer et al, 2017 ), equine encephalitis virus ( Lecollinet et al, 2020 ), lumpy skin disease virus ( Klement et al, 2020 ), and bluetongue virus (BTV) ( Saminathan et al, 2020 ) have constituted a great burden on public health and animal husbandry worldwide over the past few years. Climate change, inducing variations in rainfall, humidity, and wind patterns ( Whitehorn and Yacoub, 2019 ), accompanied by globalization and urbanization phenomena, the alteration of natural habitats, and agricultural structures ( Miles et al, 2019 ), all can affect arthropod reproduction, development, distribution, and feeding behavior.…”

Aedes mosquitoes in the emerging threat of urban yellow fever transmission

“…Fortunately, even though the environment favours YFV transmission, the YFV importation in 2016 did not lead to any autochthonous transmission. However, Guangzhou remains a city in Southeast Asia possessing the highest probability of YFV outbreaks 107 . Moreover, the distribution of the main YF vector Ae .…”

“…However, Guangzhou remains a city in Southeast Asia possessing the highest probability of YFV outbreaks. 107 Moreover, the distribution of the main YF vector Ae. aegypti is moving north and has reached southern China, in a region only 500 km away from Guangzhou.…”