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Challenges in Emerging and Reemerging Arboviral Diseases: The Examples of Oropouche and Yellow Fever.

The global burden of arboviral diseases continues to rise with alarming frequency and impact [...].

Timeliness of yellow fever specimen collection and transport in Ghana, 2018-2022.

Yellow fever is a mosquito-borne viral hemorrhagic fever, and recent outbreaks of yellow fever have occurred in multiple African countries, including Ghana (2021-2022). Delayed diagnosis of yellow fever may cause increased morbidity and mortality. To improve timely detection of yellow fever, we need to better understand the factors contributing to diagnostic delays. We analyzed the diagnostic testing timeline of all suspected yellow fever cases in Ghana from 2018-2022. For these patients we calculated the days from symptom onset to specimen collection and arrival at the National Public Health …

Targeting Yellow-Fever Virus: Development of a specific aptamer to NS1 protein.

Yellow Fever Virus (YFV), a mosquito-borne flavivirus, remains a significant public health concern despite the availability of effective vaccines. Accurate differential diagnosis continues to be challenging due to the high antigenic similarity among flaviviruses such as dengue and Zika, which compromises the specificity of current serological assays. Aptamers have emerged as promising alternatives to antibodies for diagnostic applications because of their high specificity, thermal stability, and ease of synthesis. In this study, we developed a DNA aptamer (Flav5) targeting the nonstructural pr…

Неожиданная коррекция поведения желтых комаров лихорадки с учетом высоких температур.

Температура является одним из основных экологических факторов распространения заболеваний, передаваемых через комары, поскольку она влияет на историю жизни как комаров, так и патогенов, содержащихся в них. Понимание термической биологии комаров имеет важное значение для разработки моделей прогнозирования риска таких заболеваний. Москиты могут реагировать на температуру путем микрообитационного отбора через тепловые предпочтения. Однако пока не считается, что комары могут адаптироваться к изменяющимся температурам, например во время изменения климата, и изменять свои предпочтения по сравнению с

Совпадение в аннотации оригинала
Temperature is a major ecological driver of mosquito-borne diseases as it influences the life-history of both the mosquito and the pathogen … d alter their preference over evolutionary time. We investigated this by rearing six cohorts of the yellow fever mosquito Aedes aegypti at two temperatures (24 °C, 30 °C) for 20 generations and used these cohorts to explicitly separate the effects of long-term evolution and within-generation acclimation on their thermal preferences in a thermal gradient of 20- …

A Systematic Review of Yellow Fever Outbreaks and Public Health Responses in Nigeria.

BACKGROUND: Yellow fever (YF) outbreaks continue to occur in Nigeria with a high mortality rate despite a well-established mode of transmission and the availability of a potent vaccine. This review is aimed at describing the epidemiology, determinants, and public health responses of yellow fever outbreaks in Nigeria from 1864 to 2020. METHODOLOGY: The guidelines for the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) were used to conduct the review from November 2020 to April 2021. PubMed database, WHO library databases, and Google Scholar were used to search for re…

Wandering epizootics and zones of emergence: Constructing yellow fever endemicity in Africa.

This paper examines the distinction drawn between endemic and epidemic yellow fever in the twentieth century and the policy implications of conceptualizing yellow fever as distinct in different world regions. The history of yellow fever research in Africa reveals how particular perceptions of place undergirded evolving scientific knowledge of yellow fever epidemiology. Efforts to map yellow fever endemicity in Africa and to understand the endemic threat of "jungle" yellow fever unfolded within a colonial framework that viewed Africa and Africans as "diseased." The study explores how the notion…

A neutralizing-protective supersite of human monoclonal antibodies for yellow fever virus.

The yellow fever virus (YFV) is a life-threatening human pathogen. Owing to the lack of available therapeutics, non-vaccinated individuals are at risk. Here, we isolated eight human monoclonal antibodies that neutralize YFV infection. Five recognized overlapping epitopes and exhibited potent neutralizing activity. Two (YD6 and YD73) were ultra-potent and conferred complete protection against the lethal challenge of YFV as both prophylactics and therapeutics in a mouse model. Crystal structures revealed that YD6 engaged the YFV envelope protein in both pre- and post-fusion states, suggesting vi…

Yellow fever vaccination before and during the covid-19 pandemic in Brazil.

OBJECTIVE: To analyze the number of yellow fever vaccine doses administered before and during the covid-19 pandemic in Brazil. METHODS: This is an ecological, time series study based on data from the National Immunization Program. Differences between the median number of yellow fever vaccine doses administered in Brazil and in its regions before (from April/2019 to March/2020) and after (from April/2020 to March/2021) the implementation of social distancing measures in the country were assessed via the Mann-Whitney test. Prais-Winsten regression models were used for time series analyses. RES…

Seasonal and inter-annual drivers of yellow fever transmission in South America.

In the last 20 years yellow fever (YF) has seen dramatic changes to its incidence and geographic extent, with the largest outbreaks in South America since 1940 occurring in the previously unaffected South-East Atlantic coast of Brazil in 2016-2019. While habitat fragmentation and land-cover have previously been implicated in zoonotic disease, their role in YF has not yet been examined. We examined the extent to which vegetation, land-cover, climate and host population predicted the numbers of months a location reported YF per year and by each month over the time-period. Two sets of models were…

Herpes Infections in Suspected Cases of Yellow Fever in the Democratic Republic of the Congo.

In the battle to quickly identify potential yellow fever arbovirus outbreaks in the Democratic Republic of the Congo, active syndromic surveillance of acute febrile jaundice patients across the country is a powerful tool. However, patients who test negative for yellow fever virus infection are too often left without a diagnosis. By retroactively screening samples for other potential viral infections, we can both try to find sources of patient disease and gain information on how commonly they may occur and co-occur. Several human arboviruses have previously been identified, but there remain man…

[Spatial-temporal diffusion of yellow fever in a state in Southeast Brazil in 2017].

The objective was to analyze the diffusion of cases of yellow fever in time and space in the epidemic of 2017 in the state of Espírito Santo, Brazil. An ecological observational study was performed with spatial analysis of yellow fever cases. Georeferencing of information and spatial analysis used the digital grid for the state of Espírito Santo, divided into 78 municipalities (counties), using the Arcgis software, 10.3. Geostatistical analysis was performed using the ordinary kriging function. The study found an incidence of 4.85/100,000 inhabitants of sylvatic yellow fever in Espírito Santo …

Generation of a reporter yellow fever virus for high throughput antiviral assays.

Yellow fever virus (YFV), a member of the Flaviviridae family, is an arthropod-borne virus that can cause severe disease in humans with a lethality rate of up to 60%. Since 2017, increases in YFV activity in areas of South America and Africa have been described. Although a vaccine is available, named strain 17D (Theiler and Smith, 1937), it is contraindicated for use in the elderly, expectant mothers, immunocompromised people, among others. To this day there is no antiviral treatment against YFV to reduce the severity of viral infection. Here, we used a circular polymerase extension reaction (…

Limited evolution of the yellow fever virus 17d in a mouse infection model.

By infecting mice with the yellow fever virus vaccine strain 17D (YFV-17D; Stamaril®), the dose dependence and evolutionary consequences of neurotropic yellow fever infection was assessed. Highly susceptible AG129 mice were used to allow for a maximal/unlimited expansion of the viral populations. Infected mice uniformly developed neurotropic disease; the virus was isolated from their brains, plaque purified and sequenced. Viral RNA populations were overall rather homogenous [Shannon entropies 0-0.15]. The remaining, yet limited intra-host population diversity (0-11 nucleotide exchanges per gen…

Estimating the number of unvaccinated Chinese workers against yellow fever in Angola.

BACKGROUND: A yellow fever epidemic occurred in Angola in 2016 with 884 laboratory confirmed cases and 373 deaths. Eleven unvaccinated Chinese nationals working in Angola were also infected and imported the disease to China, thereby presenting the first importation of yellow fever into Asia. In Angola, there are about 259,000 Chinese foreign workers. The fact that 11 unvaccinated Chinese workers acquired yellow fever suggests that many more Chinese workers in Angola were not vaccinated. METHODS: We applied a previously developed model to back-calculate the number of unvaccinated Chinese worke…

Immunogenicity and safety of yellow fever vaccine in HIV-1-infected patients.

OBJECTIVES: The objective of this study is to investigate immunogenicity and safety of the yellow fever vaccine (YFV) in HIV-infected (HIV+) patients with high CD4 T-cell counts. DESIGN: In this prospective, comparative study of YFV-naive adults: 40 HIV+ under antiretroviral therapy (ART) with CD4 T-cell count above 350 cells/μl and plasma HIV-RNA less than 50 copies/ml for at least 6 months and 31 HIV-negative (HIV-) received one injection of the YF-17D strain vaccine. METHODS: Serologic response was assessed by using a plaque reduction neutralizing test and YFV-specific T cells by using an…