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ELECTROPHORESIS EXPERIMENTS WITH THE VIRUS AND PROTECTIVE BODIES OF YELLOW FEVER.

1. When suspended in slightly alkaline (pH 7.4 to 7.8) saline dilutions of clear, hemoglobin-free normal monkey serum, the virus of yellow fever from infected monkeys and from infected, but blood-free, mosquitoes, usually acts as if it were possessed of a positive electrical charge. 2. The virus tends to assume a negative charge in fluids having a slightly acid reaction. 3. The isoelectric point of the virus seems to be in the neighborhood of pH 7.0, possibly ranging from pH 7.3 to pH 6.9. 4. Exposure to fluid having a reaction of pH 5.0 for 3 hours appeared to inactivate the virus. 5. In expe

Simultaneous detection of Dengue virus, Chikungunya virus, Zika virus, Yellow fever virus and West Nile virus.

Although certain mosquito-borne virus, such as Dengue virus (DENV), Chikungunya virus (CHIKV), Zika virus (ZIKV), Yellow fever virus (YFV) and West Nile virus (WNV), are an important public health concern in those countries where transmitter mosquitoes are endemic, several cases of travelers from those endemic countries have been recently reported in Europe. Thus, early diagnosis of these viruses is essential for patient management and adoption of preventive measures. An assay for the simultaneous detection of DENV, CHIKV, ZIKV, YFV and WNV based on a multiplex real-time (RT)-PCR and its usefu…

Transmission of yellow fever vaccine virus from breast feeding mothers to their infants: reporting of yellow fever virus (YFV) RNA detection in milk specimens.

BACKGROUND: Because of yellow fever's serious impact on health, vaccination is the principal strategy to control the disease. Administration of the yellow fever vaccine to breastfeeding women should be before they complete 9 months post-delivery, in order to prevent transmission of the yellow fever vaccine virus to their infants through breast feeding. This study aimed to confirm whether the excretion of yellow fever vaccine virus is in milk of vaccinated breastfeeding mothers and to confirm the probable transmission to their infants through breast milk. METHODS: Samples were taken as follows

Genomic and epidemiological monitoring of yellow fever virus transmission potential.

The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian Aedes species mosquitos highlights a need to monitor the risk of reestablishment of urban YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-…

Филогеномический анализ раскрывает эволюцию вируса желтой лихорадки внутри хостов.

Вирус желтой лихорадки (YFV) недавно появился во время крупных вспышек в Африке и Бразилии, и первые импортированные в Азию пациенты напомнили о проблемах эволюции YFV. Здесь мы показываем филогеномию YFV с серийными клиническими образцами инфекций YFV 2016 года. Филогенетика показала, что штаммы 2016 года были близки к штамму в Анголе 1971 года и только три аминокислотные изменения были новыми для других линий. Глубокая последовательность вирусных геномов выявила 101 внутреннюю вариацию одного нуклеотида (ISNV) и 234 единичные нуклеотидные полиморфизмы (SNPs). Анализ распределения ИСНВ и мути

Совпадение в аннотации оригинала
The yellow fever virus (YFV) recently reemerged in the large outbreaks in Africa and Brazil, and the first imported patients into Asia have recalled the concerns of YFV evolution. Here we show phylogenomics of YFV with serial clinical samples of the 2016 YFV infections. Phylogenetics exhibited that the 2016 strains were close to Angola 1971 strains and only …

What Does the Future Hold for Yellow Fever Virus? (I).

The recent resurgence of yellow fever virus (YFV) activity in the tropical regions of Africa and South America has sparked renewed interest in this infamous arboviral disease. Yellow fever virus had been a human plague for centuries prior to the identification of its urban transmission vector, the Aedes (Stegomyia) aegypti (Linnaeus) mosquito species, and the development of an efficient live-attenuated vaccine, the YF-17D strain. The combination of vector-control measures and vaccination campaigns drastically reduced YFV incidence in humans on many occasions, but the virus never ceased to circ…

A DNA vaccine against yellow fever virus: development and evaluation.

Attenuated yellow fever (YF) virus 17D/17DD vaccines are the only available protection from YF infection, which remains a significant source of morbidity and mortality in the tropical areas of the world. The attenuated YF virus vaccine, which is used worldwide, generates both long-lasting neutralizing antibodies and strong T-cell responses. However, on rare occasions, this vaccine has toxic side effects that can be fatal. This study presents the design of two non-viral DNA-based antigen formulations and the characterization of their expression and immunological properties. The two antigen form

Transfusion-related transmission of yellow fever vaccine virus--California, 2009.

In the United States, yellow fever (YF) vaccination is recommended for travelers and active duty military members visiting endemic areas of sub-Saharan Africa and Central/South America. The American Red Cross recommends that recipients of YF vaccine defer blood product donation for 2 weeks because of the theoretical risk for transmission from a viremic donor. On April 10, 2009, a hospital blood bank supervisor learned that, on March 27, blood products had been collected from 89 U.S. active duty trainees who had received YF vaccine 4 days before donation. This report summarizes the subsequent i

A recombinant Yellow Fever 17D vaccine expressing Lassa virus glycoproteins.

The Yellow Fever Vaccine 17D (YFV17D) has been used as a vector for the Lassa virus glycoprotein precursor (LASV-GPC) resulting in construction of YFV17D/LASV-GPC recombinant virus. The virus was replication-competent and processed the LASV-GPC in cell cultures. The recombinant replicated poorly in guinea pigs but still elicited specific antibodies against LASV and YFV17D antigens. A single subcutaneous injection of the recombinant vaccine protected strain 13 guinea pigs against fatal Lassa Fever. This study demonstrates the potential to develop an YFV17D-based bivalent vaccine against two vir

Surveillance for yellow fever virus in eastern Senegal during 1993.

During the 1993 rainy season, 15,806 mosquitoes, including 14,304 Aedes ssp., were collected and tested for virus infection in 702 and 547 pools, respectively. Aedes furcifer (Edwards) was the most abundant species collected throughout the survey period. Yellow fever (YF) virus was detected in 187 pools: Ae. furcifer (123 isolates), Ae. taylori (Edwards) (41 isolates), and Ae. luteocephalus (Newstead) (23 isolates). A high prevalence of immunoglobulin (IgG) antibodies was found in human and simian populations. Results clearly indicated that increased sylvatic YF activity in eastern Senegal has

Glycosylation and secretion of yellow fever virus nonstructural protein NS1.

The flavivirus genome codes for structural and nonstructural proteins which are produced from a common polyprotein precursor by proteolytic processing. The nonstructural protein NS1 is hypothesized to be involved in virus assembly and maturation as well as in protective immunity. This paper describes the synthesis of several forms of yellow fever (YF) virus NS1 protein during virus cultivation in vitro. These include cell-associated and secreted NS1 forms, the major difference among these being their N-linked glycosylation status. High-mannose and complex (or hybrid)-type moieties were identif

Effect of human gamma interferon on yellow fever virus infection.

We studied yellow fever virus infection in two species of monkey: Saimiri sciureus (squirrel monkeys) and Macaca mulatta (rhesus monkeys). Human gamma interferon was administered intravenously in five equal doses, one was given 24 hr before infection followed by four doses 24 hr apart. Interferon reduced the levels and duration of viremia and the severity of hepatitis in squirrel monkeys. Interferon prolonged survival time and delayed the appearance of viremia and hepatitis in infected rhesus monkeys, but it did not change overall mortality.

Трансовариальная передача вируса желтой лихорадки комарами (Aedes aegypti).

Женские комары Aedes aegypti, инфицированные вирусом желтой лихорадки внутри грудной клетки, передали вирус небольшой процент своего потомства F1. Зараженные потомки были получены из стерилизованных на поверхности, а также из неочищенных яиц, что указывает на трансовариальную передачу вируса. Вертикальная передача вируса желтой лихорадки у комаров может быть альтернативным механизмом биологического выживания вируса в неблагоприятных периодах или при отсутствии восприимчивых носителей позвоночных.

Совпадение в аннотации оригинала
Female Aedes aegypti mosquitoes infected with yellow fever virus by intrathoracic inoculation transmitted the virus to a small percentage of their F1 progeny. Infected offspring were obtained from surface-sterilized as well as from untreated eggs, indicating that the virus was transovarially transmitted. Vertical transmission of yellow fever virus in mosquit…

Yellow fever virus. II. Factors affecting the plaque neutralization test.

In studies on the factors and conditions influencing the yellow fever (YF) virus plaque neutralization test, 60 min was found to be the minimal time necessary for equilibration of the virus-antibody complex at 23 and 37 C. Maximal virus titers in the diluent controls and the pre- and postinoculation serum-containing mixtures occurred by the 60-min adsorption time. Serum neutralization indices also seemed to level by this time. Heating (56 C for 30 min) decreased the neutralizing capacity of serum. However, the slope of the neutralization curve was not affected. The addition of native (unheated

Visualization of yellow fever virus infection in mice using a bioluminescent reporter virus.

Yellow fever virus (YFV) is a re-emerging flavivirus, which can lead to severe clinical manifestations and high mortality, with no specific antiviral therapies available. The live-attenuated yellow fever vaccine 17D (YF17D) has been widely used for over eighty years. However, the emergence of yellow fever vaccine-associated viscerotropic disease (YFL-AVD) and yellow fever vaccine-associated neurotropic disease (YFL-AND) raised non-negligible concerns. Additionally, the attenuation mechanism of YF17D is still unclear. Thus, the development of convenient models is crucial to understand the mecha…

Stability of yellow fever virus under recombinatory pressure as compared with chikungunya virus.

Recombination is a mechanism whereby positive sense single stranded RNA viruses exchange segments of genetic information. Recent phylogenetic analyses of naturally occurring recombinant flaviviruses have raised concerns regarding the potential for the emergence of virulent recombinants either post-vaccination or following co-infection with two distinct wild-type viruses. To characterize the conditions and sequences that favor RNA arthropod-borne virus recombination we constructed yellow fever virus (YFV) 17D recombinant crosses containing complementary deletions in the envelope protein coding …

Changing epidemiology of yellow fever virus in Oyo State, Nigeria.

BACKGROUND: Yellow Fever is an acute viral hemorrhagic disease endemic in tropical Africa and Latin America and is transmitted through infec … received yellow fever vaccine. CONCLUSIONS: In conclusion, the increase in the circulation of the yellow fever virus in the state reiterates the state is at a high risk of yellow fever transmission and underlines the need for viable interventions such as environmental hygiene to rid the environment of the disease vector's ecological niche and improving routine EPI …