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rift valley fever antibody in human sera collected after an outbreak in domestic animals in kenya. 19921440789
rift valley fever: the role of the vervet monkey as a reservoir or maintenance host for this virus. 1978418540
an outbreak of rift valley fever in northeastern kenya, 1997-98.in december 1997, 170 hemorrhagic fever-associated deaths were reported in garissa district, kenya. laboratory testing identified evidence of acute rift valley fever virus (rvfv). of the 171 persons enrolled in a cross-sectional study, 31(18%) were anti-rvfv immunoglobulin (ig) m positive. an age-adjusted igm antibody prevalence of 14% was estimated for the district. we estimate approximately 27,500 infections occurred in garissa district, making this the largest recorded outbreak of rvfv in eas ...200211897064
vector competence of kenyan culex zombaensis and culex quinquefasciatus mosquitoes for rift valley fever virus.rift valley fever (rvf) continues to be a significant problem in kenya as well as in egypt, yemen, and saudi arabia. in order to determine the ability of kenyan mosquitoes to transmit rvf virus (rvfv), we collected mosquitoes in the lake naivasha region of kenya and evaluated them for their potential to transmit rvfv under laboratory conditions. after feeding on a hamster (mesocricetus auratus) with a viremia of 10(9.7) plaque-forming units of virus/ml of blood, culex zombaensis were highly susc ...200718240513
serosurvey for selected infectious disease agents in free-ranging black and white rhinoceros in africa.two hundred and eighty one serum samples collected from free-ranging black (diceros bicornis) and white (ceratotherium simum) rhinoceros, in the republic of south africa (rsa), namibia, and kenya from 1987-97, were examined for antibody to 16 different infectious agents. positive antibody titers were detected against akabane (59.8%), bluetongue (55%), african horse sickness (27.9%), epizootic haemorrhagic disease of deer (19.4%), parainfluenza type 3 (25.3%), bovine herpes virus 1 (3.1%), equine ...200010813614
climate and satellite indicators to forecast rift valley fever epidemics in kenya.all known rift valley fever virus outbreaks in east africa from 1950 to may 1998, and probably earlier, followed periods of abnormally high rainfall. analysis of this record and pacific and indian ocean sea surface temperature anomalies, coupled with satellite normalized difference vegetation index data, shows that prediction of rift valley fever outbreaks may be made up to 5 months in advance of outbreaks in east africa. concurrent near-real-time monitoring with satellite normalized difference ...199910411500
serum antibody to rift valley fever virus in african carnivores. 19968784515
experimental infection of the african buffalo with the virus of rift valley fever. 19817344184
using a field quantitative real-time pcr test to rapidly identify highly viremic rift valley fever cases.approximately 8% of rift valley fever (rvf) cases develop severe disease, leading to hemorrhage, hepatitis, and/or encephalitis and resulting in up to 50% of deaths. a major obstacle in the management of rvf and other viral hemorrhagic fever cases in outbreaks that occur in rural settings is the inability to rapidly identify such cases, with poor prognosis early enough to allow for more-aggressive therapies. during an rvf outbreak in kenya in 2006 to 2007, we evaluated whether quantitative real- ...200919171680
possible vectors of rift valley fever in kenya. 19806111141
rift valley fever in kenya: the presence of antibody to the virus in camels (camelus dromedarius).five hundred and seventy-one camel sera collected after an epizootic of rift valley fever were examined for antibody to the virus. clinical disease had not been observed in cattle and sheep in the ecosystems shared with the camels. positive sera with high titres of serum neutralizing antibody were found in 22% of camels at one of the seven sampling sites.19853989285
the horizontal distribution of aedes pupae and their subsequent adults within a flooded dambo in kenya: implications for rift valley fever virus control. 19883225577
an assessment of the regional and national socio-economic impacts of the 2007 rift valley fever outbreak in kenya.although rift valley fever (rvf) has significant impacts on human health and livestock production, it can also induce significant (and often overlooked) economic losses among various stakeholders in the marketing chain. this work assesses and quantifies the multi-dimensional socio-economic impacts of the 2007 rvf outbreak in kenya based on a rapid assessment of livestock value chains in the northeast part of the country and a national macroeconomic analysis. although study results show negative ...201020682906
efficacy of a sustained-release methoprene formulation on potential vectors of rift valley fever virus in field studies in kenya. 19892614412
genetic variation among geographic isolates of rift valley fever virus.the genetic variation of rift valley fever virus (rvfv) was estimated by sequencing a portion of the m segment rna of 22 isolates from a variety of host species collected over 34 years in 6 african countries. the m segment rna of the egyptian isolate, zh501, which has been molecularly cloned and sequenced, was used as a reference for these comparisons. specific gene regions, responsible for antigenic determinants presumed to play a role in protection against disease, were emphasized in these inv ...19882462795
pretreatment of floodwater aedes habitats (dambos) in kenya with a sustained-release formulation of methoprene.effectiveness of sustained-release altosid pellets (4% ai methoprene) against floodwater mosquitoes in dambos treated at 5, 3, and 1 wk before and 1 day after flooding was determined. only 2% of aedes pupae (primarily aedes mcintoshi) survived to adults in an area treated 5 wk preflood, and no adult mosquitoes emerged from an area treated 1 day after flooding. in contrast, 12 and 16% of aedes pupae successfully survived to the adult stage in areas pretreated 3 and 1 wk, respectively, preflood. t ...19902098486
egg hatching of aedes mosquitoes during successive floodings in a rift valley fever endemic area in kenya.floodwater aedes breeding habitats in central kenya were sequentially flooded to determine the numbers of mosquito eggs hatching during each flooding. approximately 90% of the larvae sampled during 4 floodings emerged during the initial flooding. the number of aedes eggs hatching during the second flooding was lowest of all 4 floodings, and no significant differences in the amount of egg hatching during floodings 3 and 4 were seen. unhatched aedes eggs were present in soil samples collected afte ...19912045800
application of polar-orbiting, meteorological satellite data to detect flooding of rift valley fever virus vector mosquito habitats in kenya.measurements of green-leaf vegetation dynamics recorded by the advanced very high resolution radiometer instruments onboard national oceanic and atmospheric administration satellites 7 and 9 were used to derive ground moisture and rainfall patterns in kenya and monitor resultant flooding of mosquito larval habitats (dambos) likely to support rift valley fever virus vector mosquitoes (aedes and culex spp.). satellite-derived data from mid-1981 to december 1988 have been analysed with correspondin ...19901983457
mosquito species collected from a marsh in western kenya during the long rains.a total of 475,431 mosquitoes representing 8 genera and 43 species were collected from a marsh in the western kenya highlands to determine species composition and succession in relation to the epidemiology of rift valley fever virus. culex pipiens was the most common species, totalling 92.3% of the collection, followed by cx. zombaensis (2.2%), anopheles coustani (1.1%), an. squamosus (0.8%), mansonia uniformis (0.6%), coquillettidia microannulatus (0.5%), uranotaenia mashonaensis (0.5%), ma. af ...19911686445
isolation of rift valley fever virus from mosquitoes (diptera: culicidae) collected during an outbreak in domestic animals in kenya.during an outbreak of rift valley fever (rvf) in livestock near lake naivasha, rift valley province, kenya, 61,347 mosquitoes (1,287 pools) collected in co2-baited light traps yielded seven viral isolates. five isolates of rvf virus were recovered from 18,831 culex zombaensis theobald and one from 14,439 mansonia africana (theobald). one isolate of a bunyamwera group virus was recovered from 1,175 aedes quasiunivittatus (theobald).19911676073
observations on the epidemiology of rift valley fever in kenya.the epizootic range of rift valley fever in kenya is defined from the results of virus isolations during epizootics, and form an extensive serological survey of cattle which were exposed during an epizootic. a study of the sera from a wide range of wild bovidae sampled immediately after the epizootic, showed that they did not act as reservoir or amplifying hosts for rvf. virus isolation attempts from a variety of rodents proved negative. rift valley fever did not persist between epizootics by pr ...19751058243
spectrum of rift valley fever virus transmission in kenya: insights from three distinct regions.rift valley fever virus (rvfv) is an emerging pathogen that maintains high biodefense priority based on its threat to livestock, its ability to cause human hemorrhagic fever, and its potential for aerosol spread. to define the range of human transmission during inter-epidemic and epidemic periods in kenya, we tested archived sera from defined populations (n = 1,263) for anti-rvfv igg by elisa and plaque reduction neutralization testing. rvfv seroprevalence was 10.8% overall and varied significan ...200717488893
blood-feeding patterns of culex quinquefasciatus and other culicines and implications for disease transmission in mwea rice scheme, kenya.studies were conducted in mwea rice scheme, kenya during the period april 2005 and january 2007 to determine the host-feeding pattern of culicine mosquitoes. mosquitoes were collected indoors and outdoors and tested for human, bovine, goat, and donkey blood meals by an enzyme-linked immunosorbent assay. a total of 1,714 blood-engorged samples comprising culex quinquefasciatus say (96.1%), culex annulioris theobald (1.8%), culex poicilipes theobald (0.9%), aedes cuminsi theobald (1.0%), aedes tay ...200818297310
interepidemic rift valley fever virus seropositivity, northeastern kenya.most outbreaks of rift valley fever (rvf) occur in remote locations after floods. to determine environmental risk factors and long-term sequelae of human rvf, we examined rates of previous rift valley fever virus (rvfv) exposure by age and location during an interepidemic period in 2006. in a randomized household cluster survey in 2 areas of ijara district, kenya, we examined 248 residents of 2 sublocations, gumarey (village) and sogan-godud (town). overall, the rvfv seropositivity rate was 13% ...200818680647
fatal outcome of hepatitis a virus (hav) infection in a traveler with incomplete hav vaccination and evidence of rift valley fever virus infection.hepatitis a virus (hav) infection is rarely fatal except in patients with chronic liver disease. in the case reported here, an elderly women died of hav infection 12 years after incomplete hav vaccination. the possible role of a concordant rift valley fever virus infection acquired in kenya is discussed.200818768649
multiple virus lineages sharing recent common ancestry were associated with a large rift valley fever outbreak among livestock in kenya during 2006-2007.rift valley fever (rvf) virus historically has caused widespread and extensive outbreaks of severe human and livestock disease throughout africa, madagascar, and the arabian peninsula. following unusually heavy rainfall during the late autumn of 2006, reports of human and animal illness consistent with rvf virus infection emerged across semiarid regions of the garissa district of northeastern kenya and southern somalia. following initial rvf virus laboratory confirmation, a high-throughput rvf d ...200818786992
effect of controlled burning on survival of floodwater aedes eggs in kenya.the effect of controlled burning on the survival of aedes mosquito eggs was evaluated in 2 distinct dambo habitats. in a dambo dominated by grasses, egg survival was 3.3% after burning compared with 43.8% in a similar dambo that was not burned. in a dambo dominated by sedges, egg survival was 0.7% after burning compared with 28.5% in a similar dambo that was not burned. mortality of mosquito eggs appeared to be caused by high temperatures associated with the fire and not elapsed time since egg s ...19938468577
arbovirus surveillance of mosquitoes collected at sites of active rift valley fever virus transmission: kenya, 2006-2007.mosquitoes collected during an outbreak of rift valley fever in kenya from december 2006 to february 2007 were tested to isolate other mosquito-borne arboviruses circulating in the region. twenty-seven virus isolations were made comprising seven viruses from three arbovirus families.200919658258
marburg, ebola and rift valley fever virus antibodies in east african primates.sera from 464 primates held at four institutes in kenya were tested by indirect immunofluorescence for the presence of antibodies against marburg, ebola, congo haemorrhagic fever, rift valley fever and lassa viruses. four of 136 vervet monkeys were positive for marburg virus antibodies and three of 184 baboons had antibodies against ebola virus. one baboon was positive for marburg virus antibodies. two vervet monkeys, three baboons and one grivet monkey (of 56 tested) had antibodies against rift ...19826810518
an investigation of a major outbreak of rift valley fever in kenya: 2006-2007.an outbreak of rift valley fever (rvf) occurred in kenya during november 2006 through march 2007. we characterized the magnitude of the outbreak through disease surveillance and serosurveys, and investigated contributing factors to enhance strategies for forecasting to prevent or minimize the impact of future outbreaks. of 700 suspected cases, 392 met probable or confirmed case definitions; demographic data were available for 340 (87%), including 90 (26.4%) deaths. male cases were more likely to ...201020682900
antibodies against haemorrhagic fever viruses in kenya populations.human sera from lodwar (77 sera), nzoia (841 sera), masinga (251 sera), laisamis (174 sera) and the malindi/kilifi area (556 sera) in kenya were tested by indirect immunofluorescence for antibodies against marburg, ebola (zaire and sudan strains), congo haemorrhagic fever, rift valley fever and lassa viruses. antibodies against ebola virus, particularly the zaire strain, were detected in all regions and were, over-all, more abundant than antibodies against the other antigens. ebola and marburg a ...19836419422
risk factors for severe rift valley fever infection in kenya, 2007.a large rift valley fever (rvf) outbreak occurred in kenya from december 2006 to march 2007. we conducted a study to define risk factors associated with infection and severe disease. a total of 861 individuals from 424 households were enrolled. two hundred and two participants (23%) had serologic evidence of acute rvf infection. of these, 52 (26%) had severe rvf disease characterized by hemorrhagic manifestations or death. independent risk factors for acute rvf infection were consuming or handli ...201020682901
rift valley fever virus epidemic in kenya, 2006/2007: the entomologic investigations.in december 2006, rift valley fever (rvf) was diagnosed in humans in garissa hospital, kenya and an outbreak reported affecting 11 districts. entomologic surveillance was performed in four districts to determine the epidemic/epizootic vectors of rvf virus (rvfv). approximately 297,000 mosquitoes were collected, 164,626 identified to species, 72,058 sorted into 3,003 pools and tested for rvfv by reverse transcription-polymerase chain reaction. seventy-seven pools representing 10 species tested po ...201020682903
rift valley fever outbreak in livestock in kenya, 2006-2007.we analyzed the extent of livestock involvement in the latest rift valley fever (rvf) outbreak in kenya that started in december 2006 and continued until june 2007. when compared with previous rvf outbreaks in the country, the 2006-07 outbreak was the most extensive in cattle, sheep, goats, and camels affecting thousands of animals in 29 of 69 administrative districts across six of the eight provinces. this contrasted with the distribution of approximately 700 human rvf cases in the country, whe ...201020682907
rift valley fever virus (family bunyaviridae, genus phlebovirus). isolations from diptera collected during an inter-epizootic period in kenya.a total of 134 876 diptera collected in kenya during a 3-year period were tested in 3383 pools for rift valley fever (rvf) virus. nineteen pools of unengorged mosquitoes were found positive for rvf. all isolations were made from specimens collected at or near the naturally or artificially flooded grassland depressions that serve as the developmental sites for the immature stages of many mosquito species. the isolation of virus from adult male and female a. lineatopennis which had been reared fro ...19852862206
epidemiological assessment of the rift valley fever outbreak in kenya and tanzania in 2006 and 2007.to capture lessons from the 2007 rift valley fever (rvf) outbreak, epidemiological studies were carried out in kenya and tanzania. somali pastoralists proved to be adept at recognizing symptoms of rvf and risk factors such as heavy rainfall and mosquito swarms. sandik, which means "bloody nose," was used by somalis to denote disease consistent with rvf. somalis reported that sandik was previously seen in 1997/98, the period of the last rvf epidemic. pastoralists communicated valuable epidemiolog ...201020682908
arbovirus prevalence in mosquitoes, kenya.few studies have investigated the many mosquito species that harbor arboviruses in kenya. during the 2006-2007 rift valley fever outbreak in north eastern province, kenya, exophilic mosquitoes were collected from homesteads within 2 affected areas: gumarey (rural) and sogan-godud (urban). mosquitoes (n = 920) were pooled by trap location and tested for rift valley fever virus and west nile virus. the most common mosquitoes trapped belonged to the genus culex (75%). of 105 mosquito pools tested, ...201121291594
postepidemic analysis of rift valley fever virus transmission in northeastern kenya: a village cohort study.in endemic areas, rift valley fever virus (rvfv) is a significant threat to both human and animal health. goals of this study were to measure human anti-rvfv seroprevalence in a high-risk area following the 2006-2007 kenyan rift valley fever (rvf) epidemic, to identify risk factors for interval seroconversion, and to monitor individuals previously exposed to rvfv in order to document the persistence of their anti-rvfv antibodies.201121858236
rift valley fever virus activity in east africa in 1989. 19921355315
prevalence of antibodies against rift valley fever virus in kenyan wildlife.rift valley fever virus (rvfv) is an arbovirus associated with periodic outbreaks, mostly on the african continent, of febrile disease accompanied by abortion in livestock, and a severe, fatal haemorrhagic syndrome in humans. however, the maintenance of the virus during the inter-epidemic period (iep) when there is low or no disease activity detected in livestock or humans has not been determined. this study report prevalence of rvfv-neutralizing antibodies in sera (n=896) collected from 16 keny ...200817988425
rift valley fever outbreak--kenya, november 2006-january 2007.in mid-december 2006, several unexplained fatalities associated with fever and generalized bleeding were reported to the kenya ministry of health (kmoh) from garissa district in north eastern province (nep). by december 20, a total of 11 deaths had been reported. of serum samples collected from the first 19 patients, rift valley fever (rvf) virus rna or immunoglobulin m (igm) antibodies against rvf virus were found in samples from 10 patients; all serum specimens were negative for yellow fever, ...200717268404
viral haemorrhagic fever surveillance in kenya, 1980-1981.following two cases of marburg virus disease in kenya in 1980, viral haemorrhagic fever surveillance was undertaken in western kenya. over a 21-month period investigations, including virus isolation attempts, patient and contact serology, visits to areas where suspected cases occurred, interviewing family members and neighbours of suspected cases and following up any additional illnesses in these areas, were carried out. during the study two cases were found that were likely to have been ebola h ...19836684336
rift valley fever. a survey for antibody to the virus in bird species commonly found in situations considered to be enzootic. 1979531912
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