infection of an aedes aegypti cell line with infectious arbovirus-antibody complexes.aedes aegypti cells exposed to infectious complexes of wn or yf virus and homologous antiserum produced lower yields of virus over a 10-day observation period than were produced by aedes aegypti cells treated with a comparable dose of virus mixed with non-immune serum. when ae. aegypti cells were infected with wn virus mixed with mve, nta, den-2 or yf antisera the virus yield over 10 days was lower than in cell cultures infected at similar titres with mixtures of wn virus with non-immune serum. ...1976982518
passage of yellow fever virus: its effect on infection and transmission rates in aedes aegypti.the effect of successive lytic passage of yellow fever virus on mosquito infection and transmission rates in the vector, aedes aegypti, was determined. three strains of yellow fever virus from trinidad and peru were passaged five times in suckling mouse brains and seven times in bhk-21 cells. mosquitoes were fed meals containing passaged and unpassaged viruses and infection and transmission rates were compared. rates were similar for all but one of the three virus strains grown in both substrate ...19863789277
transovarial transmission of yellow fever virus by mosquitoes (aedes aegypti).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 mosquitoes may be an alternative mechanism for biological survival of the virus during adverse periods or in the absence of susceptible vertebrate ...1979434305
pathogen transmission in relation to feeding and digestion by haematophagous arthropods.the blood feeding habit, especially among opportunist feeders such as tabanids and stomoxys is known to result in transmission of diseases for which the vectors are not the obligate or alternate hosts. thus, mechanical transmission of trypanosomes such as t. vivax can occur in cattle herds outside tsetse fly areas where tabanids are actively feeding. in the case of yaws, mechanical transmission of the spirochaetes by eye flies (hippelates pallipes) in the west indies is thought to be most likely ...1975240257
laboratory studies on the transmission of yellow fever virus by aedes (finlaya) notoscriptus (dipt., culicidae).aedes (finlaya) notoscriptus (skuse), a mosquito which occupies a similar ecological niche to aedes (stegomyia) aegypti (l), the urban vector of yellow fever virus, was screened as a possible vector of this disease. the results indicate that almost certainly ae. notoscriptus is refractory to the virus and could not act as a vector if yellow fever were introduced to australia.197796783
the enhancing effect of diethyl-amino-ethyl dextran on the infectivity of arboviruses for aedes aegypti. 19705490641
increased yellow fever virus infection and dissemination rates in aedes aegypti mosquitoes orally exposed to freshly grown virus. 19873503398
aedes aegypti and yellow fever virus: the effect of chloroquine on infection and transmission rates. 19873445296
aedes aegypti strain fitness for yellow fever virus transmission.three geographical strains of aedes aegypti from thailand (amphur), east africa (kampala), and the west indies (santo domingo) were compared for susceptibility to infection with low-passage yellow fever virus (french viscerotropic) as well as for ability to transmit virus by bite at varying extrinsic incubation periods. santo domingo strain appeared the most competent and kampala the least when mosquitoes were exposed to a low level virus-infecting blood meal; at higher virus levels, a similar t ...1977907058
urban yellow fever epidemic in western nigeria, 1987.a large epidemic of urban yellow fever occurred in april and may 1987 in oyo state, western nigeria. the principal vector was aedes aegypti, breeding in domestic water containers. the 1987 outbreak followed an epidemic of sylvatic yellow fever in eastern nigeria the previous year, and probably resulted from introduction of the virus by viraemic travellers. the outbreak in oyo state ended in early july, by which time 805 cases and 416 deaths had been officially notified. however, surveys of 3 vil ...19892617590
global climate change and infectious diseases.the effects of global climate change on infectious diseases are hypothetical until more is known about the degree of change in temperature and humidity that will occur. diseases most likely to increase in their distribution and severity have three-factor (agent, vector, and human being) and four-factor (plus vertebrate reservoir host) ecology. aedes aegypti and aedes albopictus mosquitoes may move northward and have more rapid metamorphosis with global warming. these mosquitoes transmit dengue v ...19911820262
genetic selection of a flavivirus-refractory strain of the yellow fever mosquito aedes aegypti.two inbred (isofemale) aedes aegypti mosquito lines were derived that manifested a resistant or susceptible phenotype following ingestion of yellow fever virus; lack of virus movement from the midgut defined the resistant phenotype. other flaviviruses, including dengue 1-4, uganda s, and zika, viruses behaved in a similar fashion in the two mosquito lines. crosses between the two lines produced progeny that were of intermediate susceptibility, indicating codominance; f2 backcrosses to the parent ...19911659238
[transovarial transmission of arboviruses by mosquitoes (author's transl)].an important aspect of the epidemiology of arboviruses is the manner in which the viruses are maintained during winter, dry season, or other adverse environmental periods when their arthropod hosts are inactive. one possibility is that the viruses survive in arthropods. in the case of mosquito-borne viruses, it is probable that such viruses could be maintained in this manner only if they were transmitted from one insect generation to the next by transovarial transmission. such transmission was r ...19816116146
morphogenesis of yellow fever virus in aedes aegypti cultured cells. ii. an ultrastructural study.the growth and intracytoplasmic development of two yellow fever virus strains (wild and french neurotropic) were studied in aedes aegypti cells (clone c 17). despite a longer period of latency for the vaccine virus, infected cells appeared similar. the cisternae of the rough endoplasmic reticulum (rer) were swollen and formed vesicles which contained the virus. this rer appeared to be the predominant locus of viral synthesis and maturation. cytopathic effect appeared when the cells were filled w ...19817283005
epidemic yellow fever caused by an incompetent mosquito vector.arbovirus epidemics in a geographic region are believed to depend on the presence of susceptible or "competent" arthropod vectors. we demonstrate that an urban, aedes aegypti-borne, epidemic of yellow fever occurred in 1987 although the mosquito vector was relatively resistant to infection and transmitted the virus inefficiently. twenty-six percent of the experimental mosquitoes from the epidemic area that ingested yellow fever virus became infected and only 7% of these transmitted the virus. in ...19892623418
virulence and pathogenesis of yellow fever virus serially passaged in cell culture.viscerotropic virulence of the asibi strain of yellow fever virus (yfv) for monkeys has been known to be lost after serial passage in hela cell monolayers. this phenomenon was investigated in several other mammalian and insect tissue cell lines. assay in monkeys of original seed virus and of virus after 7 and 11 passages in a porcine kidney cell line (pk) indicated essentially equal infectivity and mortality. moreover, monkeys receiving the passaged virus exhibited more rapid onset of disease an ...19714998347
[program of control of aedes aegypti in mexico]. 19685741446
arbovirus studies in luanda, angola. 1. virological and serological studies during a yellow fever epidemic.a yellow fever epidemic broke out in luanda, angola, in january 1971 and was halted in less than 3 months by prompt mass vaccination and intensive antimosquito measures. nine strains of yellow fever virus were isolated from hospitalized cases, but attempts to isolate the virus from aedes aegypti mosquitos failed. a serological survey for antibodies to arboviruses in 589 sera from unvaccinated persons showed that two arboviruses were circulating in the epidemic area: the yellow fever virus and th ...19734545154
[reinfestation of brasil by aedes aegypti. considerations on the threat of urbanization of jungle yellow fever virus in the reinfested region]. 19685705657
[yellow fever and eradication of aedes aegypti]. 19694238707
geographic genetic differentiation and arbovirus competency: aedes aegypti and yellow fever. 19853870635
selection for susceptibility and refractoriness of aedes aegypti to oral infection with yellow fever virus.artificial selection on strains of aedes aegypti showing susceptibility and refractoriness to oral infection with yellow fever virus (yfv) suggests that there is a significant genetic component to this trait. using a population with an average susceptibility of 15%, inbreeding of isofemale lines followed by individual selection produced susceptible (29% infected) and refractory (11% infected) lines. the difference between lines was largely apparent before individual selection, which failed to in ...19853834805
oral infection of aedes aegypti with yellow fever virus: geographic variation and genetic considerations.twenty-eight populations representing a worldwide distribution of aedes aegypti were tested for their ability to become orally infected with yellow fever virus (yfv). populations had been analyzed for genetic variations at 11 isozyme loci and assigned to one of 8 genetic geographic groups of ae. aegypti. infection rates suggest that populations showing isozyme genetic relatedness also demonstrate similarity to oral infection rates with yfv. the findings support the hypothesis that genetic variat ...19853834804
restriction fragment length polymorphism mapping of quantitative trait loci for malaria parasite susceptibility in the mosquito aedes aegypti.susceptibility of the mosquito aedes aegypti to the malarial parasite plasmodium gallinaceum was investigated as a quantitative trait using restriction fragment length polymorphisms (rflp). two f2 populations of mosquitoes were independently prepared from pairwise matings between a highly susceptible and a refractory strain of a. aegypti. rflp were tested for association with oocyst development on the mosquito midgut. two putative quantitative trait loci (qtl) were identified that significantly ...19957789771
current status of aedes aegypti eradication in the western hemisphere. 19674951703
biological characterization of plaque-size variants of yellow fever virus in mosquitoes and mice.we isolated plaque-size variants of a south american strain of yellow fever virus, and compared their ability to infect orally and be transmitted by vector aedes aegypti mosquitoes with that of the uncloned, parental virus. we analyzed the same clonal isolates in mouse virulence experiments. no significant differences could be demonstrated in the capacities of the variants to infect and be transmitted by mosquitoes or in mouse virulence tests. the 17d vaccine virus (derived from the african asib ...19882902770
arboviruses and lemurs in madagascar: experimental infection of lemur fulvus with yellow fever and west nile previous serological surveys of lemurs in madagascar, antibodies against flaviviruses were frequently detected. to examine the epidemiological role of lemur fulvus, experimental infections with yellow fever (yf) virus and west nile (wn) virus were performed. yf and wn infections were clinically unapparent. a 3 to 4-day-long viremia, with moderate levels was observed with yf virus. wn virus, especially the strain isolated in madagascar, provoked a 4 to 6-day-long viremia sufficient to infect a ...19852862804
vector competence of aedes albopictus from houston, texas, for dengue serotypes 1 to 4, yellow fever and ross river viruses.a combination of virus infection and transmission experiments showed that a houston, texas strain of aedes albopictus is a competent vector for dengue (den), yellow fever (yf) and ross river (rr) viruses. however, at 14 days incubation, den virus infection rates in a puerto rican strain of aedes aegypti were significantly higher for each of the four den serotypes, except den-1, than in houston ae. albopictus fed simultaneously on the same virus suspensions. the degree of correlation between diss ...19872849638
yellow fever: an update.yellow fever, the original viral haemorrhagic fever, was one of the most feared lethal diseases before the development of an effective vaccine. today the disease still affects as many as 200,000 persons annually in tropical regions of africa and south america, and poses a significant hazard to unvaccinated travellers to these areas. yellow fever is transmitted in a cycle involving monkeys and mosquitoes, but human beings can also serve as the viraemic host for mosquito infection. recent increase ...200111871403
[current situation of yellow fever in latin america].yellow fever endemicity is currently stabilized in south america: an average of 115 cases has officially been notified each year since 25 years (between 12 and 304 annual cases). these figures are underevaluated but no epidemic has been observed since 1983. only sporadic or limited grouped cases have been reported. all declared cases correspond to people who have been infected within sylvatic areas, mainly adult forestmen. within the last years, the majority of cases have occurred in peru and bo ...19937819801
morphogenesis of yellow fever virus in aedes aegypti cultured cells. i. isolation of different cellular clones and the study of their susceptibility to infection with the virus.we report the isolation of 19 cellular clones of aedes aegypti and analyze their susceptibility to infection with yellow fever virus, in comparison with the uncloned cells. four types of clones were found, different in their morphology, their metabolism and their virus production. the c 17 clone produces the most virus, not only with respect to the other aedes aegypti clones, but also to other uncloned arthropod cells published in the literature. a cytopathic effect exists in the virus infected ...19817025663
yellow fever in the gambia, 1978--1979: entomological aspects and epidemiological entomological survey was conducted in the gambia in january 1979, during the last phase of a yellow fever (yf) outbreak which began during the previous rainy season. in the dry conditions which prevailed in january, aedes aegypti was the only yf vector present. two yf virus strains were isolated from females of this mosquito species caught in a village of western gambia, where active human cases were documented. the ae. aegypti breeding sites were exclusively of the domestic type. larval indi ...19807435794
epidemic dengue 2 in the city of djibouti 1991-1992.from october 1991 to february 1992, an outbreak of acute fever (in which thick blood films were negative for malaria) spread rapidly in the city of djibouti, djibouti republic, affecting all age groups and both nationals and foreigners. the estimated number of cases was 12,000. the clinical features were consistent with a non-haemorrhagic dengue-like illness. serum samples from 91 patients were analysed serologically for flavivirus infection (dengue 1-4, west nile, yellow fever, zika, banzi, and ...19968758061
yellow fever: a decade of reemergence.since the 1980s, yellow fever has reemerged across africa and in south america. the total of 18 735 yellow fever cases and 4522 deaths reported from 1987 to 1991 represents the greatest amount of yellow fever activity reported to the world health organization (who) for any 5-year period since 1948. there is an excellent vaccine against yellow fever. at present, a high proportion of travelers to at-risk areas are reported to be immunized, reflecting widespread knowledge about the international he ...19968827969
[reflection on 2 current viral diseases: yellow fever and dengue].yellow fever and dengue are two current viral diseases induced by flaviviruses and usually transmitted by the same mosquito vector, aedes aegypti. from 1987 to 1991, 18,753 cases of yellow fever, mainly from africa, have been notified to who, leading to 4,522 deaths. on the other hand, who estimates that 2.5 billions individuals living in tropical areas are at risk to contract dengue fevers. in fact, 500,000 patients are hospitalized each year for dengue hemorrhagic fever/dengue shock syndrome a ...19979347008
first evidence of natural vertical transmission of yellow fever virus in aedes aegypti, its epidemic vector.entomological investigations were conducted in 1995 in senegal, following a yellow fever (yf) outbreak. a total of 1125 mosquitoes collected in the field, including males, females and 12-48 h old newly emerged adults reared from wild-caught larvae, were tested for yf virus. among the 22 species captured, aedes aegypti was the most common. 'wild' vectors of yf were also captured, including a. furcifer, a. metallicus and a. luteocephalus. in all, 28 yf virus isolations were made: 19 from a. aegypt ...19979463659
stable transformation of the yellow fever mosquito, aedes aegypti, with the hermes element from the housefly.the mosquito aedes aegypti is the world's most important vector of yellow fever and dengue viruses. work is currently in progress to control the transmission of these viruses by genetically altering the capacity of wild ae. aegypti populations to support virus replication. the germ-line transformation system reported here constitutes a major advance toward the implementation of this control strategy. a modified hermes transposon carrying a 4.7-kb fragment of genomic dna that includes a wild-type ...19989520437
engineered resistance in aedes aegypti to a west african and a south american strain of yellow fever virus.double subgenomic sindbis (dssin) viruses were engineered to transduce mosquito cells with antisense rna derived either from the premembrane (prm) or polymerase (ns5) coding regions of the 17d vaccine strain of yellow fever virus (yfv). aedes albopictus c6/36 cells were infected at high multiplicities of infection (moi) with each dssin virus. forty-eight hours later, the transduced cells were challenged with an moi of 0.1 of the asibi strain of yfv. at 72-hr postchallenge, the cells were assayed ...19989598458
re-emergence of yellow fever in senegal in outbreak of yellow fever (yf) occurred in the central part of senegal during october 1995. thirty-one probable cases were detected and 79 cases were confirmed either by igm elisa or by virus isolation (30 strains isolated). the case fatality rate was 18.9%. incidence of the infection was evaluated by a serosurvey in the area. males 10-29 years old belonging to the peul ethnic group were more affected. moreover, 28 yf virus strains were isolated from mosquitoes and larvae pools and vertical tr ...19989684637
[aedes albopictus in rural zone of brazil and its implication in the wild yellow fever transmission].larvae and adult forms of aedes albopictus were found during ecological study of anopheline mosquitos in the rural zone of the state of mato grosso do sul in brazil. this occurrence was registered, for the first time in brazil, in an enzoootic area if sylvatic yellow fever virus. this implies a potential risk of the transfer of this virus to an urban area infested with aedes aegypti.199910436626
[present status of an arbovirus infection: yellow fever, its natural history of hemorrhagic fever, rift valley fever].in the early 20th century, when it was discovered that the yellow fever virus was transmitted in its urban cycle by aedes aegypti, measures of control were introduced leading to its disappearance. progressive neglect of the disease, however, led to a new outbreak in 1927 during which the etiological agent was isolated; some years later a vaccine was discovered and yellow fever disappeared again. in the 1960s, rare cases of encephalitis were observed in young children after vaccination and the ad ...199910690474
aedes aegypti: a quantitative trait locus (qtl) influencing filarial worm intensity is linked to qtl for susceptibility to other mosquito-borne pathogens.because intensity of infection was significantly increased in a substrain of aedes aegypti selected for susceptibility to the filarial worm, brugia malayi, experiments were designed to assess numbers of microfilariae (mf) ingested and midgut penetration by mf in this susceptible substrain as compared to a refractory substrain selected from the same parental stock. refractory mosquitoes ingested significantly fewer mf than susceptible mosquitoes and significantly fewer numbers of mf penetrated th ...19957498432
[yellow fever epidemiology in brazil].we have carried out a meticulous time-space-analysis of the incidence of yellow fever in humans in brazil from 1954 to 1972 and especially from 1973 to 1999. this study has added to our knowledge of the epidemiology of yellow fever and enabled us to redefine epidemiological zones and determine their geographical limits. the endemic area is located within the amazon basin; here cases are scattered and generally limited in number. however, there are also "foci of endemic emergence" within this are ...200111681224
oral susceptibility to yellow fever virus of aedes aegypti from brazil.the oral susceptibility to yellow fever virus was evaluated in 23 aedes aegypti samples from brazil. six ae. aegypti samples from africa, america and asia were also tested for comparison. mosquito samples from asia showed the highest infection rates. infection rates for the brazilian ae. aegypti reached 48.6%, but were under 13% in 60% of sample tested. we concluded that although the low infection rates estimated for some brazilian mosquito samples may not favor the establishment of urban cycle ...200212048581
[yellow fever epidemic in the extreme north of cameroon in 1990: first yellow fever virus isolation in cameroon].some two years ago, suspicious cases of yellow fever (yf) were reported in northern cameroon. a deadly epidemic broke out during the second half of the rainy season (from 15 september to 22 december 1990) with 180 known cases, of which 125 died. the real figures could have been between 5000 and 20,000 cases with between 500 and 1000 deaths. the affected area was within the yellow fever belt, which is situated around latitude 11 degrees north and 14 degrees east. in this mountainous area (altitud ...19938490979
jungle yellow fever: clinical and laboratorial studies emphasizing viremia on a human case.the authors report the clinical, laboratorial and epidemiological aspects of a human case of jungle yellow fever. the patient suffered from fever, chills, sweating, headaches, backaches, myalgia, epigastric pains, nausea, vomiting, diarrhea and prostration. he was unvaccinated and had been working in areas where cases of jungle yellow fever had been confirmed. investigations concerning the yellow fever virus were performed. blood samples were collected on several days in the course of the illnes ...19958599063
possible contributing factors to the paucity of yellow fever epidemics in the ashanti region of ghana, west africa.yellow fever virus vectors identified in the ashanti region of ghana included aedes aegypti, aedes africanus, aedes luteocephalus and aedes vittatus. other mosquito species, unrelated to yellow fever transmission, identified in this study included culex tigripes, culex thalassius, culex decens, culex tarsalis, anopheles gambiae, anopheles stephansi and toxorynchites brevipalpis. factors generally known to influence yellow fever transmission were also studied in the ashanti region. these included ...19968625858
investigations into yellow fever virus and other arboviruses in the northern regions of kenya.previous studies having shown an appreciable level of yellow fever immunity to exist in northern kenya, further epidemiological and serological surveys were carried out there in 1968 in an attempt to define more clearly the distribution of yellow fever and to locate possible vector and reservoir hosts of the disease; these surveys also provided information on a number of other arboviruses.altogether 436 sera from 5 areas in northern kenya were screened by haemagglutination-inhibition tests with ...19704393661
epidemiology of tree-hole breeding mosquitoes in the tropical rainforest of imo state, south-east nigeria.the study of tree-hole breeding mosquitoes was carried out in the tropical rainforest of imo state nigeria (two rural areas and two forest reserves in some parts of orlu senatorial zone) between may-october 2002. using standard entomological procedures, two macrohabitats (natural tree-holes and bamboo traps) and two microhabitats (leaf axils of cocoyams/pineapples and leaf axils of plantain/banana) were sampled for various mosquito species. mosquitoes were recovered from all the various biotypes ...200717655174
[integrated approach to yellow fever surveillance: pilot study in senegal in 2003-2004].the aim was to undertake a pilot study of integrated surveillance of yellow fever (yf) in senegal, based on i) a human surveillance involving healthcare centers in the 11 administrative regions of the country ii) an entomological surveillance including domestic and sylvatic environment and iii) screening mosquitoes for yf virus using rt-pcr method. the integrated approach of human and entomological surveillance was conducted for 2 years (2003-2004). surveillance in human population was based on ...200717824313
transovarial transmission of yellow fever virus in stegomyia mosquitoes.transovarial transmission of two strains of yellow fever virus was demonstrated in three colonized geographical strains of aedes aegypti following infection by intrathoracic inoculation. infected progeny were detected in f1 offspring from only the first three ovarian cycles (ovc). the overall minimum filial infection rate for the first three ovc was 1:596; rates were loser in the second and third ovc. virus survived in eggs for longer than 4 months and was recovered from progeny of three immersi ...19806766282
[centenary of the discovery of yellow fever virus and its transmission by a mosquito (cuba 1900-1901)].during the 17th, 18th and 19th centuries, yellow fever has been an ordinary scourge in american cities. in the early part of the 20th century, a main discovery has been achieved in havana city, cuba, leading to direct consequences for tropical medicine, public health and virology. there, the u.s. army yellow fever commission headed by walter reed proved that yellow fever was a viral disease transmitted by a specific mosquito, stegomyia fasciata, in fact aedes aegypti l. the idea that vomito negr ...200314582304
[application of one step rt-pcr assay for detection of flavivirus rna in mosquitoes].the conditions of one step rt-pcr method for detection of virus rna in field-collected mosquitoes, and preservation period of infected mosquitoes for one step rt-pcr were examined. we compared several virus rna extraction methods with artificially contaminated mosquito pools with dengue virus (dv), japanese encephalitis virus (jev), and yellow fever virus (yfv) with a known amount of plaque forming unit (pfu) to establish the condition of one step rt-pcr. in this study, most effective rna extrac ...200314608915
aedes aegypti in brazil: genetically differentiated populations with high susceptibility to dengue and yellow fever viruses.aedes aegypti was eliminated from brazil in 1955, but re-infested the country in the 1970s. dengue outbreaks have occurred since 1981 and became endemic in several cities in brazil after 1986. urban yellow fever has not occurred since 1942, and only jungle yellow fever cases have been reported. a population genetic analysis using isoenzyme variation combined with an evaluation of susceptibility to both yellow fever and dengue 2 viruses was conducted among 23 a. aegypti samples from 13 brazilian ...200414702837
the changing epidemiology of yellow fever and dengue, 1900 to 2003: full circle?yellow fever and dengue are old diseases, having caused major epidemics in centuries past. both were effectively controlled in the mid 1900s, yellow fever in francophone africa by vaccination and yellow fever and dengue in the americas by effective control of the principal urban vector of both viruses, aedes aegypti. in the last 25 years of the 20th century, however, there was a resurgence of yellow fever in africa, and of dengue worldwide. the factors responsible for this resurgence are discuss ...200415225982
yellow fever: the recurring plague.despite the availability of a safe and efficacious vaccine, yellow fever (yf) remains a disease of significant public health importance, with an estimated 200,000 cases and 30,000 deaths annually. the disease is endemic in tropical regions of africa and south america; nearly 90% of yf cases and deaths occur in africa. it is a significant hazard to unvaccinated travelers to these endemic areas. virus transmission occurs between humans, mosquitoes, and monkeys. the mosquito, the true reservoir of ...200415487593
yellow fever virus infectivity for bolivian aedes aegypti mosquitoes.the absence of urban yellow fever virus (yfv) in bolivian cities has been attributed to the lack of competent urban mosquito vectors. experiments with aedes aegypti from santa cruz, bolivia, demonstrated infection (100%), dissemination (20%), and transmission of a bolivian yfv strain (cenetrop-322).200415498171
size heterogeneity in the 3' noncoding region of south american isolates of yellow fever virus.the 3' noncoding region (3' ncr) of flaviviruses contains secondary and tertiary structures essential for virus replication. previous studies of yellow fever virus (yfv) and dengue virus have found that modifications to the 3' ncr are sometimes associated with attenuation in vertebrate and/or mosquito hosts. the 3' ncrs of 117 isolates of south american yfv have been examined, and major deletions and/or duplications of conserved rna structures have been identified in several wild-type isolates. ...200515731274
detection of yellow fever virus nucleic acid in infected mosquitoes by rna:rna in situ in situ hybridization technique was developed for the strand-specific detection of yellow fever virus (yfv) rna. an 35s-labeled, transcribed rna probe was used to detect positive-sense polarity yfv genomic rna in infected c6/36 (aedes albopictus) cells, dissected mosquito tissues, and sections of plastic-embedded, yfv-infected aedes aegypti mosquitoes. mosquito tissues fixed in buffered formalin retained morphological integrity. the low concentrations of probe used yielded high specific signa ...19882907776
present and future arboviral threats.arthropod-borne viruses (arboviruses) are important causes of human disease nearly worldwide. all arboviruses circulate among wild animals, and many cause disease after spillover transmission to humans and agriculturally important domestic animals that are incidental or dead-end hosts. viruses such as dengue (denv) and chikungunya (chikv) that have lost the requirement for enzootic amplification now produce extensive epidemics in tropical urban centers. many arboviruses recently have increased i ...201019857523
characterization of an infectious clone of the wild-type yellow fever virus asibi strain that is able to infect and disseminate in mosquitoes.infectious clone technology provides an opportunity to study the molecular basis of arthropod-virus interactions in detail. this study describes the development of an infectious clone of the prototype yellow fever virus asibi strain (yfv-as) with the purpose of identifying sequences or domains that influence infection dynamics in the mosquito vector. the full-length cdna of yfv-as virus was produced from rt-pcr products of parental viral rna. these were cloned into a low-copy-number plasmid prev ...200515914853
possibility of hereditary transmission of yellow fever virus by aedes aegypti (linn.).attempts to obtain passage of yellow fever virus from one generation to the next in a. aegypti were unsuccessful. subcutaneous injections at varying intervals of a saline emulsion of 200 eggs laid by an infective lot of mosquitoes produced no reaction in six normal m. rhesus monkeys. negative results were also obtained in five biting and two injection experiments with progeny of the same infective lot of mosquitoes in which seven normal monkeys were used. the eggs consisted of batches laid after ...192919869656
the filtrability of yellow fever virus as existing in the mosquito.the virus of yellow fever as it exists in aëdes aegypti mosquitoes, both in their so-called infective stage and in the intermediate condition termed the "incubation period", is capable of passing through berkefeld n filters when suspended in normal monkey serum, although earlier investigators have shown that the virus from infective mosquitoes will not do so when suspended in physiological salt solution. the virus of yellow fever as it exists in mosquitoes behaves with regard to filtration throu ...192919869658
vertical transmission of the yellow fever virus by aedes aegypti (diptera, culicidae): dynamics of infection in f1 adult progeny of orally infected females.vertical transmission of yellow fever virus from orally infected females to their progeny was experimentally demonstrated in 2 aedes aegypti colonies from the dakar and koungheul regions in senegal. a total of 10,530 f1 adult mosquito progeny were tested. the overall vertical transmission rate was 0.97%, with no significant difference between the dakar and koungheul colonies. the infection rates were significantly higher in females (1.15%) than in males (0.74%) in both colonies. the virus was no ...200010761742
[development of immunizing agents against dengue].the four serotypes of dengue flaviviruses are transmitted mainly by the aedes aegypti mosquito, and some epidemics have been attributed to ae. albopictus, ae. polynesiensis, and various species of the ae. scutellaris complex. the risk factors involved in dengue mortality and morbidity are related to the human host (genetic characteristics of infected persons; lifestyles, immune status, and health conditions of people; basic sanitation of dwellings; and water supply) and to the virus (genetic var ...200010893968
[representing and intervening in public health: viruses, mosquitoes and rockefeller foundation experts in brazil].the attempts by experts from the of the rockefeller foundation (rf) to eliminate yellow fever in brazil were hampered by the pathology's low visibility. most cases of yellow fever were atypical and easily confused with other fevers. in the 1920s, the rf experts who tried to assess the presence of yellow fever relied mainly on clinical observations. in the 1930s, however, they devised indirect methods of visualizing the presence of the disease agent. visceroctomy revealed the presence of acute ca ...199816676454
engineering blood meal-activated systemic immunity in the yellow fever mosquito, aedes aegypti.progress in molecular genetics makes possible the development of alternative disease control strategies that target the competence of mosquitoes to transmit pathogens. we tested the regulatory region of the vitellogenin (vg) gene of aedes aegypti for its ability to express potential antipathogen factors in transgenic mosquitoes. hermes-mediated transformation was used to integrate a 2.1-kb vg-promoter fragment driving the expression of the defensin a (defa) coding region, one of the major insect ...200010908672
[paul-louis simond and yellow fever].p.l. simond participated in the pasteur institute mission sent to rio de janeiro from 1901 to 1905 to investigate yellow fever and was to make an important contribution to the knowledge of the disease. at that time, the aetiologic agent of yellow fever was still unknown, and its transmission by mosquitoes was controversial. several authors had observed apparent differences in the susceptibility to the illness between african and european populations. otherwise, the soundness of epidemic control ...199911000946
[transmission and conservation of the amaril virus in nature].the yellow fever virus is a monkey flavivirus transmitted by mosquitoes. the transmission cycles and vectors vary from western to eastern africa and in south america. there are two types of endemic areas where the virus is maintained: humid forests and emerging zones and areas where intermediary and urban epidemics occur. on both continents, the virus circulates in forest areas by moving epizooties from one region to another among non immune monkeys. the virus can also be maintained in an enzoot ...199911000958
yellow fever: a disease that has yet to be conquered.yellow fever virus (yfv) is the prototype member of the genus flavivirus, a group of viruses that are transmitted between vertebrates by arthropod vectors. the virus is found in tropical regions of africa and south america and is transmitted to primates by mosquitoes: aedes spp. in africa and haemagogus and sabethes spp. in south america. despite the availability of an effective vaccine, yellow fever (yf) is considered a reemerging disease owing to its increased incidence in the past 25 years. m ...200716913829
role of the yellow fever virus structural protein genes in viral dissemination from the aedes aegypti mosquito virus vaccines are key components in controlling arboviral diseases, but they must not disseminate in or be transmitted by mosquito vectors. although the cycles in which many mosquito-borne viruses are transmitted are well understood, the role of viral genetics in these processes has not been fully elucidated. yellow fever virus (yfv) is an important arbovirus and the prototype member of the family flaviviridae. here, yfv was used in aedes aegypti mosquitoes as a model to investi ...200616963758
laboratory vector competence experiments with yellow fever virus and five south african mosquito species including aedes aegypti.three domestic and peridomestic mosquito species, selected because their prevalence, distribution and ecology favoured them as potential urban vectors of yellow fever (yf) in south africa, were submitted to numerous tests for infectivity [measured as dose needed to infect 50% of the mosquitoes (mid50)], mainly with a kenyan strain (bc7914) of the virus. use of a nigerian virus strain (tvp1617) did not significantly alter infectivity. after artificial infective blood meals with titres of 7.0-8.0 ...200212474475
rna-seq analyses of blood-induced changes in gene expression in the mosquito vector species, aedes aegypti.hematophagy is a common trait of insect vectors of disease. extensive genome-wide transcriptional changes occur in mosquitoes after blood meals, and these are related to digestive and reproductive processes, among others. studies of these changes are expected to reveal molecular targets for novel vector control and pathogen transmission-blocking strategies. the mosquito aedes aegypti (diptera, culicidae), a vector of dengue viruses, yellow fever virus (yfv) and chikungunya virus (cv), is the sub ...201121276245
new tools for surveillance of adult yellow fever mosquitoes: comparison of trap catches with human landing rates in an urban environment.a novel mosquito trapping system, the bg-sentinel trap, was evaluated as a monitoring tool for adult aedes aegypti in field tests in the city of belo horizonte, brazil. human landing/biting collections, a gas-powered co2 trap, and a fay-prince trap with only visual cues serving as references to evaluate the efficacy of the new trap. the bg-sentinel is a simple suction trap that uses upward-directed air currents as well as visual cues to attract mosquitoes. the trap was tested with a new dispense ...200617019768
movement of dengue vectors between the human modified environment and an urban forest in rio de janeiro.the movement of aedes aegypti (l.) and aedes albopictus (skuse) females between sylvatic and urban environments was investigated by marking, releasing, and recapturing adults and by identifying rubidium (rb)-marked eggs of females that were released after taking a bloodmeal containing rbci. when released in the forest, ae. albopictus females flew as far as 1000 m and reached houses within 1 wk. when ae. albopictus were released close to houses, most females were recaptured near the release point ...200617162942
manipulation of the yellow fever virus non-structural genes 2a and 4b and the 3'non-coding region to evaluate genetic determinants of viral dissemination from the aedes aegypti midgut.although much is known about the ecology, epidemiology, and molecular biology of mosquito-borne viruses, the viral factors that allow transmission by mosquitoes to humans or animals remain unknown. using infectious clones of disseminating (asibi) and non-disseminating (17d) yellow fever viruses (yfv), we produced chimeric viruses to evaluate the role of different viral genes in dissemination. previously, we showed that virus produced from an infectious clone containing the structural genes of 17 ...200617172386
vector competence of brazilian aedes aegypti and ae. albopictus for a brazilian yellow fever virus isolate.because the potential urban yellow fever (yf) mosquito vectors aedes aegypti and ae. albopictus are at historical highs in brazil, both in terms of density and geographical range, we assessed the risk of an urban yf epidemic in brazil. we evaluated and confirmed in a laboratory setting the vector competence of brazilian ae. aegypti for a currently circulating strain of yf virus, and investigated the potential for brazilian ae. albopictus to transmit yf.200212625133
transmission of yellow fever virus by aged aedes aegypti and comments on some other mosquitovirus relationships. 196213943133
characterization of the antigen distribution and tissue tropisms of three phenotypically distinct yellow fever virus variants in orally infected aedes aegypti mosquitoes.arbovirus dissemination from the midgut of a vector mosquito is a critical step in facilitating virus transmission to a susceptible host. we previously characterized the genetic determinants of yellow fever virus (yfv) dissemination from the aedes aegypti mosquito midgut using 2 genetically and phenotypically distinct strains of yfv: the wild-type, disseminating yfv asibi strain and the attenuated, midgut-restricted yfv 17d vaccine strain. we examined the process of viral dissemination in yfv-in ...200818494601
the enigma of yellow fever in east africa.despite a safe and effective vaccine, there are approximately 200,000 cases, including 30,000 deaths, due to yellow fever virus (yfv) each year, of which 90% are in africa. the natural history of yfv has been well described, especially in west africa, but in east africa yellow fever (yf) remains characterised by unpredictable focal periodicity and a precarious potential for large epidemics. recent outbreaks of yf in kenya (1992-1993) and sudan (2003 and 2005) are important because each of these ...200818615782
[presence of haemagogus equinus theobald, 1903 (diptera: culicidae), in soledad and malambo, in the province of atlántico, colombia].yellow fever is a serious illness public health importance and is transmitted by mosquitoes of the genera haemagogus and sabethes in the rural and forest environments, and by aedes aegypti in the urban setting. in colombia, haemagogus janthinomys and h. equinus are considered efficient vectors of this viral disease.200818645665
the effect of colonization upon aedes aegypti susceptibility to oral infection with yellow fever virus.two colonies of aedes aegypti were established from two independent collections from vero beach, florida. eleven sequential generations of the first colony were tested for variation in oral susceptibility to infection with yellow fever virus (yfv). each generation was also assayed for genetic variability at seven enzyme loci using electrophoretic techniques. significant differences in infection rates were detected between some generations. these differences were significantly correlated with gen ...19846476217
ecdysis triggering hormone signaling in the yellow fever mosquito aedes the end of each developmental stage, the yellow fever mosquito aedes aegypti performs the ecdysis behavioral sequence, a precisely timed series of behaviors that culminates in shedding of the old exoskeleton. here we describe ecdysis triggering hormone-immunoreactive inka cells located at branch points of major tracheal trunks and loss of staining coincident with ecdysis. peptides (aeaeth1, aeaeth2) purified from extracts of pharate 4th instar larvae have--prxamide c-terminal amino acid seque ...200919298818
reconsideration of histopathology and ultrastructural aspects of the human liver in yellow fever.yellow fever is a re-emerging infectious disease that currently is at risk of urbanization due to the advance of the aedes aegypti vector. the disease affects about 200,000 individuals annually, mainly in tropical africa and south america. it causes severe disease involving especially the liver, with lesions characterized by midzonal steatosis, apoptosis and lytic necrosis of the hepatocytes. quantitative histological and immunohistochemical analysis of 53 human hepatic samples demonstrated apop ...200515829426
homing endonucleases catalyze double-stranded dna breaks and somatic transgene excision in aedes aegypti.aedes aegypti is a major vector of arthropod-borne viruses such as yellow fever virus and dengue viruses. efforts to discern the function of genes involved in important behaviours, such as vector competence and host seeking through reverse genetics, would greatly benefit from the ability to generate targeted gene disruptions. homing endonucleases are selfish elements which catalyze double-stranded dna (dsdna) breaks in a sequence-specific manner. in this report we demonstrate that the homing end ...200919754740
the incubation period of yellow fever in the mosquito.1. the yellow fever virus was found in infectious form in aedes aegypti throughout the entire period of the extrinsic incubation, as demonstrated by the injection of the bodies of mosquitoes into normal rhesus monkeys at daily intervals after the insects had fed on an infected animal. 2. the virus was transmitted through the bite of the mosquitoes, in one experiment on and after the 9th day, and in two experiments on the 12th day after the initial infecting feed. 3. the pathologic changes produc ...192819869467
studies on cyclic passage of yellow fever virus in south american mammals and mosquitoes; marsupials (metachirus nudicaudatus and marmosa) in combination with aedes aegypti as vector. 194818898700
recent laboratory contributions to the control of yellow fever: (section of tropical diseases and parasitology).the most important recent laboratory contributions to the control of yellow fever will be briefly summarized under three headings: (1) methods of diagnosis, (2) transmission, and (3) protection.(1) methods of diagnosis.-the development of improved methods of identification, in particular by immunity tests, has made it possible to diagnose yellow fever with much greater certainty. moreover, since the immunity following an attack of the disease is usually of life-long duration, it is possible to d ...193319989606
[epidemiological situation of yellow fever in burkina faso from 2003 to 2008].despite the existence of antiamaril vaccine in the routine expanded program of immunization (epi) in burkina faso, yellow fever cases still occur in the country. in collaboration with who, the national health authorities set up a surveillance system through the national reference laboratory in centre muraz (bobo-dioulasso). all samples of feverish icterus cases of the 63 health districts of the country were analysed in this lab for m immunoglobulin using enzyme linked immunosorbent assay (elisa) ...201020101488
infection and vertical transmission of kamiti river virus in laboratory bred aedes aegypti mosquitoes.kamiti river virus (krv) is an insect-only flavivirus that was isolated from field-collected ae. macintoshi mosquitoes in 1999, and is closely related to cell fusing agent virus. both of these viruses belong to the family flaviviridae, which also contains other viruses of medical importance, such as yellow fever virus, west nile virus and dengue. because ae. macintoshi is the only known natural host to krv, the main objective of this study was to establish the possibility that other mosquito hos ...200720337552
the single kinin receptor signals to separate and independent physiological pathways in malpighian tubules of the yellow fever the past, we have used the kinins of the cockroach leucophaea (the leucokinins) to evaluate the mechanism of diuretic action of kinin peptides in malpighian tubules of the yellow fever mosquito aedes aegypti. now using the kinins of aedes (the aedeskinins), we have found that in isolated aedes malpighian tubules all three aedeskinins (1 microm) significantly 1) increased the rate of fluid secretion (v(s)), 2) hyperpolarized the basolateral membrane voltage (v(bl)), and 3) decreased the input ...201020538895
incubation periods of yellow fever virus.yellow fever virus is a global health threat due to its endemicity in parts of africa and south america where human infections occur in residents and travelers. to understand yellow fever dynamics, it is critical to characterize the incubation periods of the virus in vector mosquitoes and humans. here, we compare four statistical models of the yellow fever incubation periods fitted with historical data. the extrinsic incubation period in the urban vector aedes aegypti was best characterized with ...201020595499
a list of mosquito species of the brazilian state of pernambuco, including the first report of haemagogus janthinomys (diptera: culicidae), yellow fever vector and 14 other species (diptera: culicidae).besides mosquito species adapted to urban environments (culex quinquefasciatus, aedes aegypti and aedes albopictus), only 15 species of anopheles had been recorded in the state of pernambuco.201020802950
early history of laboratory breeding of aedes aegypti (diptera: culicidae) focusing on the origins and use of selected strains.the yellow fever mosquito, aedes aegypti (l.) (diptera: culicidae), is well recognized for its extensive adaptation to diverse ecological conditions and for genetic variation. recognizing the importance of strain variation of this mosquito, researchers have established a large number of laboratory strains. some of the popular strains have been used for research for years in many laboratories around the world. however, the exact origins of many of these strains are unknown. in this review, public ...201021175042
[entomological investigations conducted around ten cases of yellow fever in 2009 in the denguélé sanitary region, côte-d'ivoire.]in november 2009, ten suspicious cases of yellow fever, including six deaths, were notified in the region of denguélé, in the northwest of côte-d'ivoire. in order to evaluate the extent of yellow fever virus circulation and the risk for local people, a mission of entomological investigation was carried out by the ministry of health and public hygiene of côte-d'ivoire. entomological investigations were conducted in the villages of confirmed cases (banakoro and tron-touba) and the centers of consu ...201121293956
a protocol for collecting and staining hemocytes from the yellow fever mosquito <em>aedes aegypti</em>.mosquitoes are vectors for a number of disease-causing pathogens such as the yellow fever virus, malaria parasites and filarial worms. laboratories are investigating anti-pathogen components of the innate immune system in disease vector species in the hopes of generating transgenic mosquitoes that are refractory to such pathogens(1, 2). the innate immune system of mosquitoes consists of several lines of defense (3). pathogens that manage to escape the barrier imposed by the epithelium-lined mosq ...201121633325
vector competence of australian mosquitoes for yellow fever virus.the vector competence of australian mosquitoes for yellow fever virus (yfv) was evaluated. infection and transmission rates in cairns and townsville populations of aedes aegypti and a brisbane strain of ae. notoscriptus were not significantly different from a well-characterized yfv-susceptible strain of ae. aegypti. after exposure to 10⁷·² tissue culture infectious dose (tcid₅₀)/ml of an african strain of yfv, > 70% of ae. aegypti and ae. notoscriptus became infected, and > 50% transmitted the v ...201121896802
annotation and expression profiling of apoptosis-related genes in the yellow fever mosquito, aedes aegypti.apoptosis has been extensively studied in drosophila by both biochemical and genetic approaches, but there is a lack of knowledge about the mechanisms of apoptosis regulation in other insects. in mosquitoes, apoptosis occurs during plasmodium and arbovirus infection in the midgut, suggesting that apoptosis plays a role in mosquito innate immunity. we searched the aedes aegypti genome for apoptosis-related genes using drosophila and anopheles gambiae protein sequences as queries. in this study we ...200818252247
substitution of wild-type yellow fever asibi sequences for 17d vaccine sequences in chimerivax-dengue 4 does not enhance infection of aedes aegypti address concerns that a flavivirus vaccine/wild-type recombinant virus might have a high mosquito infectivity phenotype, the yellow fever virus (yfv) 17d backbone of the chimerivax-dengue 4 virus was replaced with the corresponding gene sequences of the virulent yfv asibi strain. field-collected and laboratory-colonized aedes aegypti mosquitoes were fed on blood containing each of the viruses under investigation and held for 14 days after infection. infection and dissemination rates were base ...200818266608
fever versus fever: the role of host and vector susceptibility and interspecific competition in shaping the current and future distributions of the sylvatic cycles of dengue virus and yellow fever virus.two different species of flaviviruses, dengue virus (denv) and yellow fever virus (yfv), that originated in sylvatic cycles maintained in non-human primates and forest-dwelling mosquitoes have emerged repeatedly into sustained human-to-human transmission by aedes aegypti mosquitoes. sylvatic cycles of both viruses remain active, and where the two viruses overlap in west africa they utilize similar suites of monkeys and aedes mosquitoes. these extensive similarities render the differences in the ...201323523817
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