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Immunogenicity of Yellow Fever Vaccine Coadministered With MenAfriVac in Healthy Infants in Ghana and Mali.

BACKGROUND: Yellow fever (YF) is still a major public health problem in endemic regions of Africa and South America. In Africa, one of the main control strategies is routine vaccination within the Expanded Programme on Immunization (EPI). A new meningococcal A conjugate vaccine (PsA-TT) is about to be introduced in the EPI of countries in the African meningitis belt, and this study reports on the immunogenicity of the YF-17D vaccines in infants when administered concomitantly with measles vaccine and PsA-TT. METHODS: Two clinical studies were conducted in Ghana and in Mali among infants who r…

[YEL-AND meningoencephalitis in a 4-year-old boy consecutive to a yellow-fever vaccine].

Yellow fever is a vector-borne disease transmitted by an endemic mosquito in sub-Saharan Africa and tropical South America. It causes fever and possibly liver and renal failure with hemorrhagic signs, which may be fatal. The yellow-fever vaccine is an attenuated vaccine that is recommended for all travelers over the age of 9 months in high-risk areas. Adverse effects have been reported: minor symptoms (such as viral syndrome), hypersensitivity reactions, and major symptoms such as viscerotropic disease (YEL-AVD) and neurotropic disease (YEL-AND). The yellow-fever vaccine-associated autoimmune …

Development of a membrane adsorber based capture step for the purification of yellow fever virus.

Yellow fever (YF) is an endemic disease in some tropical areas of South America and Africa that presents lethality rate between 20 and 50%. There is no specific treatment and to control this disease a highly effective live-attenuated egg based vaccine is widely used for travelers and residents of areas where YF is endemic. However, recent reports of rare, sometimes fatal, adverse events post-vaccination have raised concerns. In order to increase safety records, alternative strategies should be considered, such as developing a new inactivated vaccine using a cell culture based technology, capab…

Advice on malaria and yellow fever prevention provided at travel agencies in Cuzco, Peru.

BACKGROUND: Travelers receive medical advice from a variety of sources, including travel agencies. The aim of this study is to describe the quality of pre-travel advice provided by travel agencies in Cuzco to travelers interested in visiting malaria and yellow fever endemic areas. METHODS: Trained medical students posed as tourists and visited travel agencies in Cuzco requesting travel advice for a trip to the southern Amazon of Peru, recording advice regarding risk and prevention of malaria and yellow fever. RESULTS: A total of 163 registered travel agencies were included in the study. The …

Yellow fever virus: genetic and phenotypic diversity and implications for detection, prevention and therapy.

Yellow fever virus (YFV) is the prototypical hemorrhagic fever virus, yet our understanding of its phenotypic diversity and any molecular basis for observed differences in disease severity and epidemiology is lacking, when compared to other arthropod-borne and haemorrhagic fever viruses. This is, in part, due to the availability of safe and effective vaccines resulting in basic YFV research taking a back seat to those viruses for which no effective vaccine occurs. However, regular outbreaks occur in endemic areas, and the spread of the virus to new, previously unaffected, areas is possible. An…

Комплексная увязка, хромосома и карта генома для желтой лихорадки комаров Aedes aegypti.

Aedes aegypti, желтый комарь лихорадки, является эффективным вектором арбовирусов и удобной моделью для лабораторных исследований. Обширное картирование морфологических и молекулярных маркеров, локализованных на ряде количественных локси (QTLs) с учетом способности комаров передавать различные патогены. Однако увязка QTL с Ae. aegypti хромосомы и геномные последовательности была сопряжена с трудностями из-за низкого качества политетных хромосом и высокой фрагментации генома этого вида.На основе подхода, разработанного в нашем предыдущем исследовании, мы создали идиограммы для митотических хром

Совпадение в аннотации оригинала
BACKGROUND: Aedes aegypti, the yellow fever mosquito, is an efficient vector of arboviruses and a convenient model system for laboratory research. Extensive linkage mapping of morphological and molecular markers localized a number of quantitative trait loci (QTLs) related to the mosquito's ability to transmit various pathogens. However, linking the QTLs to A…

Evolutionary and ecological factors underlying the tempo and distribution of yellow fever virus activity.

Yellow fever virus (YFV) is historically one of the most important viruses to affect human populations. Despite the existence of highly effective vaccines for over 70 years, yellow fever remains a significant and re-emerging cause of morbidity and mortality in endemic and high-risk regions of South America and Africa. The virus may be maintained in sylvatic enzootic/epizootic, transitional and urban epidemic transmission cycles with geographic variation in terms of levels of genetic diversity, the nature of transmission cycles and patterns of outbreak activity. In this review we consider evolu…

Treatment of yellow fever virus with an adenovirus-vectored interferon, DEF201, in a hamster model.

Interferon (IFN) is an innate immune response protein that is involved in the antiviral response during viral infection. Treatment of acute … or to virus infection, which resulted in a dose-responsive, protective effect in a hamster model of yellow fever virus (YFV) disease. A DEF201 dose of 5×10(7) PFU/animal administered intranasally just prior to YFV challenge protected 100% of the animals, while a 10-fold lower DEF201 dose exhibited lower, although significant, levels of protection. Virus titers …

[Efficacy and safety of vaccination against yellow fever of persons traveling to endemic areas].

AIM: To asses the yellow fever effectiveness in persons traveling to the endemic regions, and the frequency of adverse events related to vaccine as well as the change of neutralizing antibodies in time. METHODS: Fifty three persons (25 males and 28 females, mean 43.5 years) vaccinated against yellow fever in 2004-2008 were involved to the study. In 2009 the level of serum anti-yellow fever antibodies was measured by neutralization test. MAIN OBSERVATION AND RESULTS: None of studied person demonstrated adverse events related to yellow fever vaccine. Four subjects (7.5%) did not respond appropr…

Yellow fever control in Cameroon: where are we now and where are we going?

BACKGROUND: Cameroon is one of 12 African countries that bear most of the global burden of yellow fever. In 2002 the country developed a five-year strategic plan for yellow fever control, which included strategies for prevention as well as rapid detection and response to outbreaks when they occur. We have used data collected by the national Expanded Programme on Immunisation to assess the progress made and challenges faced during the first four years of implementing the plan. METHODS: In January 2003, case-based surveillance of suspected yellow fever cases was instituted in the whole country.…

The cost of immunity in the yellow fever mosquito, Aedes aegypti depends on immune activation.

Although host immunity offers the obvious benefit of reducing parasite infection, it is often traded-off with other fitness components. We investigated whether the cost of an immune response in the yellow fever mosquito, Aedes aegypti, is modulated by the antigen that activates the melanization immune response. Thus, one of three different novel antigens were injected into the mosquito's thorax--either a glass bead, a negatively charged (C-25) Sephadex bead, or a neutral (G-25) Sephadex bead--and fecundity and bead melanization were observed. Glass beads are immunologically inert and were ther…

Efficacy of post-exposure treatment of yellow fever with ribavirin in a hamster model of the disease.

Ribavirin was evaluated as a potential treatment of yellow fever (YF) in a hamster model of the disease. Ribavirin treatment during the first five days after YF virus infection improved survival, reduced tissue damage in target organs (liver and spleen), prevented hepatocellular steatosis, and normalized alanine aminotransferase levels. The results of this study suggest that ribavirin may be effective in the early treatment of YF, and that its mechanism of action in reducing liver pathology in YF virus infection may be similar to that observed with ribavirin in the treatment of chronic hepatit…

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

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…

Yellow fever in Africa: public health impact and prospects for control in the 21st century.

In the last two decades, yellow fever re-emerged with vehemence to constitute a major public health problem in Africa. The disease has brought untold hardship and indescribable misery among different populations in Africa. It is one of Africa's stumbling blocks to economic and social development. Despite landmark achievements made in the understanding of the epidemiology of yellow fever disease and the availability of a safe and efficacious vaccine, yellow fever remains a major public health problem in both Africa and America where the disease affects annually an estimated 200,000 persons caus…

Complete nucleotide sequence and phylogeny of an American strain of yellow fever virus, TRINID79A.

Yellow fever was presumably imported to the Americas from West-Africa from the 16th to the 19th century. American and African genotypes of the virus are distinguishable, indicating separate evolution in different vector/host cycles. The complete nucleotide sequence of the yellow fever virus strain TRINID79A, isolated in Trinidad in 1979, has been established. It exhibits extensive homology with those of current West-African strains and attenuated strain FNV. However, a unique deletion of the 3' non-coding region (NCR) of the viral RNA has been identified. It indicates that RYF1 and RYF2 repeat…

Ammonia as an attractive component of host odour for the yellow fever mosquito, Aedes aegypti.

Behavioural responses of Aedes aegypti mosquitoes to ammonia were investigated in a modified Y-tube olfactometer. Ammonia was attractive in concentrations from 17 ppb to 17 ppm in air when presented together with lactic acid. Aqueous solutions of ammonia salts in concentrations comparable to those found in human sweat also increased the attractiveness of lactic acid. The role of lactic acid as an essential synergist for ammonia became further apparent by the fact that ammonia alone or in combination with carbon dioxide was not effective, even though the synergistic effect of carbon dioxide and

Yellow fever: ecology, epidemiology, and role in the collapse of the Classic lowland Maya civilization.

Mystery has long surrounded the collapse of the Classic lowland Mayan civilization of the Peten region in Guatemala. Recent population reconstructions derived from archaeological evidence from the central lowlands show population declines from urban levels of between 2.5 and 3.5 million to around 536,000 in the two hundred year interval between 800 A.D. and 1000 A.D., the period known as the Classic Maya Collapse. A steady, but lesser rate of population decline continued until the time of European contact. When knowledge of the ecology and epidemiology of yellow fever and its known mosquito ve…

[Stegomyian indices and epidemiological status of yellow fever in a rural area of the Ivory Coast].

The M'bahiakro region, located in the center of Ivory Coast and inhabited by the N'gain, has been the scene of a yellow fever epidemic since 1982. This region reunites all the conditions for cyclic emergence of the flavivirus given the current epidemiologic pattern of yellow fever in Africa. In view of this situation ORSTOM, in collaboration with the Pasteur Institute of Ivory Coast, has created a pilot zone for epidemiologic surveillance of yellow fever in this region. The N'gain region which has a total population of 12,000 living in 20 villages with between 100 and 2000 inhabitants is locat…