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infections in sentinel pigeons by sindbis and west nile viruses in south africa, with observations on culex (culex) univittatus (diptera: culicidae) attracted to these birds. 1979537007
sindbis and west nile virus infections in the witwatersrand-pretoria region.from mid-december 1983 until mid-april 1984, there was an epidemic of sindbis (sin) virus infection in the witwatersrand-pretoria region in which hundreds of human cases were diagnosed clinically. twenty-eight of these diagnoses were confirmed in the laboratory by seroconversion as being infections with sin virus, and 5 cases of infection with west nile (wn) virus were also found. attempts to isolate virus from 66 patients, mainly from serum specimens, were unsuccessful. infection rates for the ...19863016922
a survey of the mosquito and culicoides faunas at two localities in the karoo region of south africa with some observations of bionomics.the mosquito and culicoides faunas were surveyed at bethulie and luckhoff in the arid karoo region, south orange free state, to determine which species occurred, their relative prevalence and the effects of rainfall. the feeding preferences of these insects were also investigated by means of baited catches. twenty-three mosquito species and 16 culicoides species were collected. the commonest mosquito species, with their feeding preferences, if known, were as follows: culex (culex) univittatus th ...19807454229
germination, growth, and sporulation of bacillus thuringiensis subsp. israelensis in excreted food vacuoles of the protozoan tetrahymena pyriformis.spores of bacillus thuringiensis subsp. israelensis and their toxic crystals are bioencapsulated in the protozoan tetrahymena pyriformis, in which the toxin remains stable. each t. pyriformis cell concentrates the spores and crystals in its food vacuoles, thus delivering them to mosquito larvae, which rapidly die. vacuoles containing undigested material are later excreted from the cells. the fate of spores and toxin inside the food vacuoles was determined at various times after excretion by phas ...19989572947
bacillus thuringiensis and its pesticidal crystal proteins.during the past decade the pesticidal bacterium bacillus thuringiensis has been the subject of intensive research. these efforts have yielded considerable data about the complex relationships between the structure, mechanism of action, and genetics of the organism's pesticidal crystal proteins, and a coherent picture of these relationships is beginning to emerge. other studies have focused on the ecological role of the b. thuringiensis crystal proteins, their performance in agricultural and othe ...19989729609
plasmid transfer between bacillus thuringiensis subsp. israelensis strains in laboratory culture, river water, and dipteran larvae.plasmid transfer between strains of bacillus thuringiensis subsp. israelensis was studied under a range of environmentally relevant laboratory conditions in vitro, in river water, and in mosquito larvae. mobilization of pbc16 was detected in vitro at a range of temperatures, ph values, and available water conditions, and the maximum transfer ratio was 10(-3) transconjugant per recipient under optimal conditions. transfer of conjugative plasmid pxo16::tn5401 was also detected under this range of ...200111133463
the ecology of west nile virus in south africa and the occurrence of outbreaks in humans.this paper reviews studies done on west nile virus (wnv) in south africa, mainly between 1962 and 1980 on the temperate inland plateau (highveld and karoo). the virus is maintained in an enzootic transmission cycle between feral birds and the ornithophilic mosquito culex univittatus. about 30 avian species have been shown to be involved without mortality. humans, and other mammals, although they may have antibodies, are considered blind-alleys in the transmission cycle except perhaps some dogs. ...200111797772
phylogenetic relationships of southern african west nile virus isolates.phylogenetic relationships were examined for 29 southern african west nile virus (formal name west nile virus [wnv]) isolates from various sources in four countries from 1958 to 2001. in addition, sequence data were retrieved from genbank for another 23 wnv isolates and kunjin and japanese encephalitis viruses. all isolates belonged to two lineages. lineage 1 isolates were from central and north africa, europe, israel, and north america; lineage 2 isolates were from central and southern africa a ...200212141968
temperature, viral genetics, and the transmission of west nile virus by culex pipiens mosquitoes.the distribution and intensity of transmission of vector-borne pathogens can be strongly influenced by the competence of vectors. vector competence, in turn, can be influenced by temperature and viral genetics. west nile virus (wnv) was introduced into the united states of america in 1999 and subsequently spread throughout much of the americas. previously, we have shown that a novel genotype of wnv, wn02, first detected in 2001, spread across the us and was more efficient than the introduced gen ...200818584026
a simple method for determining arbovirus transmission in mosquitoes.we present a simplified method for the collection of mosquito saliva to determine culex pipiens quinquefasciatus transmission of west nile virus that can be used for experiments requiring large sample sizes.201020402359
screening mosquito house entry points as a potential method for integrated control of endophagic filariasis, arbovirus and malaria vectors.partial mosquito-proofing of houses with screens and ceilings has the potential to reduce indoor densities of malaria mosquitoes. we wish to measure whether it will also reduce indoor densities of vectors of neglected tropical diseases.201020689815
mosquito surveys and west nile virus screening in two different areas of southern portugal, 2004-2007.longitudinal mosquito surveys were carried out in southern portugal from 2004 to 2007, in a wetland area (comporta, district of setúbal) and around the perimeter of a dam irrigation plant that created the largest artificial lake in europe, 250 km(2) (alqueva, districts of evora and beja). our aim was to study the diversity, abundance, and seasonal dynamics of mosquitoes, comparing these two different areas, to screen mosquitoes for west nile virus (wnv), an arboviral agent already detected in po ...201020854020
climatic controls on west nile virus and sindbis virus transmission and outbreaks in south africa.abstract the processes influencing the magnitude of west nile virus (wnv) transmission from 1 year to the next require thorough investigation. the intensity of wnv transmission is related to the dynamics and interactions between the pathogen, vector, vertebrate hosts, and environment. climatic variability is one process that can influence interannual disease transmission. south africa has a long wnv and sindbis virus (sinv) record where consistent climate and disease relationships can be ident ...201121995260
Spatio-temporal patterns of distribution of West Nile virus vectors in eastern Piedmont Region, Italy.ABSTRACT: BACKGROUND: West Nile Virus (WNV) transmission in Italy was first reported in 1998 as an equine outbreak near the swamps of Padule di Fucecchio, Tuscany. No other cases were identified during the following decade until 2008, when horse and human outbreaks were reported in Emilia Romagna, North Italy. Since then, WNV outbreaks have occurred annually, spreading from their initial northern foci throughout the country. Following the outbreak in 1998 the Italian public health authority def ...201122152822
Globalization, land use, and the invasion of West Nile virus.Many invasive species that have been spread through the globalization of trade and travel are pathogens. A paradigmatic case is the introduction of West Nile virus (WNV) into North America in 1999. A decade of research on the ecology and evolution of WNV includes three findings that provide insight into the outcome of future pathogen introductions. First, WNV transmission in North America is highest in urbanized and agricultural habitats, in part because the hosts and vectors of WNV are abundant ...201122021850
species composition and wnv screening of mosquitoes from lagoons in a wetland area of the algarve, portugal.the aim of this study was to evaluate mosquito abundance, species diversity, larval and adult population dynamics in seven lagoons integrated in the wetland coastal system of the algarve, portugal, in the summer of 2007, as well as the screening of these for west nile virus (wnv). wnv has been isolated from mosquitoes in this region, in the summer of 2004, next to the putative area of infection of two linked human wn cases. adult mosquitoes were collected with cdc traps baited with co(2), and po ...201122347862
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
west nile virus: characteristics of an african virus adapting to the third millennium world.the emergence and spread of west nile virus (wnv) from north through south america during the last decade, and the recent outbreaks of disease in both humans and horses in europe suggest that the epidemiology of this infection is evolving. wnv is now considered among the emerging threats for both human and veterinary public health in areas like europe where it was previously regarded to as an exotic agent. further knowledge has built up from studies investigating the characteristics of the virus ...201020517488
a tyrosine-to-histidine switch at position 18 of the ross river virus e2 glycoprotein is a determinant of virus fitness in disparate hosts.arthritogenic alphaviruses are human pathogens maintained in nature through alternating replication in vertebrates and mosquitoes. using chimeric viruses, we previously reported that replacement of the pe2 coding region of the t48 strain of ross river virus (rrv-t48) with that from the attenuated dc5692 strain, which differ by 7 amino acids, resulted in an attenuated disease phenotype in a mouse model of rrv-induced rheumatic disease. here, we demonstrate that introduction of one of these amino ...201323514884
wolbachia biocontrol strategies for arboviral diseases and the potential influence of resident wolbachia strains in mosquitoes.arboviruses transmitted by mosquitoes are a major cause of human disease worldwide. the absence of vaccines and effective vector control strategies has resulted in the need for novel mosquito control strategies. the endosymbiotic bacterium wolbachia has been proposed to form the basis for an effective mosquito biocontrol strategy. resident strains of wolbachia inhibit viral replication in drosophila fruit flies and induce a reproductive phenotype known as cytoplasmic incompatibility that allows ...201626925368
climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission.arguably one of the most important effects of climate change is the potential impact on human health. while this is likely to take many forms, the implications for future transmission of vector-borne diseases (vbds), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. in part, this is owing not only to data limitations and methodological challenges when integrating climate-driven vbd models and climate change projections, but also, perhap ...025688012
the role of environmental variables on aedes albopictus biology and chikungunya epidemiology.aedes albopictus is a vector of dengue and chikungunya viruses in the field, along with around 24 additional arboviruses under laboratory conditions. as an invasive mosquito species, ae. albopictus has been expanding in geographical range over the past 20 years, although the poleward extent of mosquito populations is limited by winter temperatures. nonetheless, population densities depend on environmental conditions and since global climate change projections indicate increasing temperatures and ...023916332
mosquito-borne arbovirus surveillance at selected sites in diverse ecological zones of kenya; 2007 - 2012.increased frequency of arbovirus outbreaks in east africa necessitated the determination of distribution of risk by entomologic arbovirus surveillance. a systematic vector surveillance programme spanning 5 years and covering 11 sites representing seven of the eight provinces in kenya and located in diverse ecological zones was carried out.201323663381
isolation and phylogenetic analysis of sindbis viruses from mosquitoes in germany.a molecular survey of 16,057 mosquitoes captured in southwest germany during the summer of 2009 demonstrated the presence of sindbis virus (sinv) in culex spp. and anopheles maculipennis sensu lato. phylogenetic analysis of the german sinv strains linked them with swedish sinv strains, the causative agent of ockelbo disease in humans.201020335414
european surveillance for west nile virus in mosquito populations.a wide range of arthropod-borne viruses threaten both human and animal health either through their presence in europe or through risk of introduction. prominent among these is west nile virus (wnv), primarily an avian virus, which has caused multiple outbreaks associated with human and equine mortality. endemic outbreaks of west nile fever have been reported in italy, greece, france, romania, hungary, russia and spain, with further spread expected. most outbreaks in western europe have been due ...201324157510
climate change impacts on west nile virus transmission in a global context.west nile virus (wnv), the most widely distributed virus of the encephalitic flaviviruses, is a vector-borne pathogen of global importance. the transmission cycle exists in rural and urban areas where the virus infects birds, humans, horses and other mammals. multiple factors impact the transmission and distribution of wnv, related to the dynamics and interactions between pathogen, vector, vertebrate hosts and environment. hence, among other drivers, weather conditions have direct and indirect i ...025688020
a metapopulation model to simulate west nile virus circulation in western africa, southern europe and the mediterranean basin.in europe, virological and epidemiological data collected in wild birds and horses suggest that a recurrent circulation of west nile virus (wnv) could exist in some areas. whether this circulation is permanent (due to overwintering mechanisms) or not remains unknown. the current conception of wnv epidemiology suggests that it is not: this conception combines an enzootic wnv circulation in tropical africa with seasonal introductions of the virus in europe by migratory birds. the objectives of thi ...201020167194
whole genome phylogenetic investigation of a west nile virus strain isolated from a tick sampled from livestock in north eastern kenya.west nile virus (wnv) has a wide geographical distribution and has been associated to cause neurological disease in humans and horses. mosquitoes are the traditional vectors for wnv; however, the virus has also been isolated from tick species in north africa and europe which could be a means of introduction and spread of the virus over long distances through migratory birds. although wnv has been isolated in mosquitoes in kenya, paucity of genetic and pathogenicity data exists. we previously rep ...201425430727
ecology of west nile virus in north america.the introduction, dispersal and establishment of west nile virus in north america were reviewed, focusing on factors that may have enhanced receptivity and enabled the invasion process. the overwintering persistence of this tropical virus within temperate latitudes was unexpected, but was key in the transition from invasion to endemic establishment. the cascade of temporal events allowing sporadic amplification to outbreak levels was discussed within a future perspective.201324008376
vector databank in the indian armed forces.medical intelligence of disease vectors deals with understanding vector distribution and control.201127408077
experimental infections of wild birds with west nile virus.avian models of west nile virus (wnv) disease have become pivotal in the study of infection pathogenesis and transmission, despite the intrinsic constraints that represents this type of experimental research that needs to be conducted in biosecurity level 3 (bsl3) facilities. this review summarizes the main achievements of wnv experimental research carried out in wild birds, highlighting advantages and limitations of this model. viral and host factors that determine the infection outcome are ana ...201424531334
usutu virus. 201324659950
changing patterns of west nile virus transmission: altered vector competence and host susceptibility.west nile virus (wnv) is a flavivirus (flaviviridae) transmitted between culex spp. mosquitoes and avian hosts. the virus has dramatically expanded its geographic range in the past ten years. increases in global commerce, climate change, ecological factors and the emergence of novel viral genotypes likely play significant roles in the emergence of this virus; however, the exact mechanism and relative importance of each is uncertain. previously wnv was primarily associated with febrile illness of ...200919406093
ecological niche modelling of rift valley fever virus vectors in baringo, kenya.rift valley fever (rvf) is a vector-borne zoonotic disease that has an impact on human health and animal productivity. here, we explore the use of vector presence modelling to predict the distribution of rvf vector species under climate change scenario to demonstrate the potential for geographic spread of rift valley fever virus (rvfv).201627863533
comparison of complete genome sequences of usutu virus strains detected in spain, central europe, and africa.the complete genomic sequence of usutu virus (usuv, genus flavivirus, family flaviviridae) strain mb119/06, detected in a pool of culex pipiens mosquitoes in northeastern spain (viladecans, catalonia) in 2006, was determined and analyzed. the phylogenetic relationship with all other available complete usuv genome sequences was established. the spanish sequence investigated showed the closest relationship to the usuv prototype strain sa ar 1776 isolated in south africa in 1959 (96.9% nucleotide a ...201424746182
comparative morphological and molecular analysis confirms the presence of the west nile virus mosquito vector, culex univittatus, in the iberian peninsula.culex univittatus and culex perexiguus mosquitoes (diptera: culicidae) are competent arbovirus vectors, but with unclear morphological differentiation. in europe, and in the iberian peninsula in particular, the presence of either or both species is controversial. however, in order to conduct adequate surveillance for arboviruses in this region, it is crucial to clarify whether cx. univittatus is present or not, as well as to critically assess existing differentiation tools. this study aimed to c ...201627884174
review of west nile virus circulation and outbreak risk in madagascar: entomological and ornithological perspectives.west nile fever (wnf) is a zoonotic disease, occurring nearly globally. in madagascar, west nile virus (wnv) was first detected in 1978 from wild birds and the virus is currently distributed across the island, but no epidemic or epizootic period has been recorded. one fatal human case of wnv infection was reported in 2011, suggesting a "tip of the iceberg" phenomenon of a possible wnf epidemic/epizootic on the island. the main objective of this literature-based survey is to review patterns of wn ...201627849515
host choice and west nile virus infection rates in blood-fed mosquitoes, including members of the culex pipiens complex, from memphis and shelby county, tennessee, 2002-2003.the source of bloodmeals in 2,082 blood-fed mosquitoes collected from february 2002 through december 2003 in memphis and surrounding areas of shelby county, tennessee were determined. members of the genus culex and anopheles quadrimaculatus predominated in the collections. members of the cx. pipiens complex and cx. restuans were found to feed predominately upon avian hosts, though mammalian hosts made up a substantial proportion of the bloodmeals in these species. no significant difference was s ...200717767413
antibodies against west nile and shuni viruses in veterinarians, south africa. 025062350
a review of the vector management methods to prevent and control outbreaks of west nile virus infection and the challenge for europe.west nile virus infection is a growing concern in europe. vector management is often the primary option to prevent and control outbreaks of the disease. its implementation is, however, complex and needs to be supported by integrated multidisciplinary surveillance systems and to be organized within the framework of predefined response plans. the impact of the vector control measures depends on multiple factors and the identification of the best combination of vector control methods is therefore n ...201425015004
high prevalence of west nile virus in domestic birds and detection in 2 new mosquito species in madagascar.west nile virus is an arthropod-borne zoonosis transmitted by a large number of mosquito species, and birds play a key role as reservoir of the virus. its distribution is largely widespread over africa, asia, the americas and europe. since 1978, it has frequently been reported in madagascar. studies described a high seroprevalence level of the virus in humans in different areas of the island and a human fatal case of wnv infection was reported in 2011. despite these reports, the epidemiology of ...201626807720
a single positively selected west nile viral mutation confers increased virogenesis in american crows.west nile virus (wnv), first recognized in north america in 1999, has been responsible for the largest arboviral epiornitic and epidemic of human encephalitis in recorded history. despite the well-described epidemiological patterns of wnv in north america, the basis for the emergence of wnv-associated avian pathology, particularly in the american crow (amcr) sentinel species, and the large scale of the north american epidemic and epiornitic is uncertain. we report here that the introduction of a ...200717694056
dengue outbreak in mombasa city, kenya, 2013-2014: entomologic investigations.dengue outbreaks were first reported in east africa in the late 1970s to early 1980s including the 1982 outbreak on the kenyan coast. in 2011, dengue outbreaks occurred in mandera in northern kenya and subsequently in mombasa city along the kenyan coast in 2013-2014. following laboratory confirmation of dengue fever cases, an entomologic investigation was conducted to establish the mosquito species, and densities, causing the outbreak. affected parts of the city were identified with the help of ...201627783626
commensal viruses of mosquitoes: host restriction, transmission, and interaction with arboviral pathogens.recent advances in virus detection strategies and deep sequencing technologies have enabled the identification of a multitude of new viruses that persistently infect mosquitoes but do not infect vertebrates. these are usually referred to as insect-specific viruses (isvs). these novel viruses have generated considerable interest in their modes of transmission, persistence in mosquito populations, the mechanisms that restrict their host range to mosquitoes, and their interactions with pathogens tr ...201728096646
mosquito host choices on livestock amplifiers of rift valley fever virus in kenya.animal hosts may vary in their attraction and acceptability as components of the host location process for assessing preference, and biting rates of vectors and risk of exposure to pathogens. however, these parameters remain poorly understood for mosquito vectors of the rift valley fever (rvf), an arboviral disease, and for a community of mosquitoes.201627036889
recent outbreaks of rift valley fever in east africa and the middle east.rift valley fever (rvf) is an important neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health. mosquitoes in the aedes genus have been considered as the reservoir, as well as vectors, since their transovarially infected eggs withstand desiccation and larvae hatch when in contact with water. however, different mosquito species serve as epizootic/epidemic vectors of rvf, creating a complex epidemiologic pattern in east africa. the recent rvf outbreaks i ...201425340047
comparison of methods for xenomonitoring in vectors of lymphatic filariasis in northeastern tanzania.monitoring wuchereria bancrofti infection in mosquitoes (xenomonitoring) can play an important role in determining when lymphatic filariasis has been eliminated, or in focusing control efforts. as mosquito infection rates can be low, a method for collecting large numbers of mosquitoes is necessary. gravid traps collected large numbers of culex quinquefasciatus in tanzania, and a collection method that targets mosquitoes that have already fed could result in increased sensitivity in detecting w. ...201526350454
a crossover study to evaluate the diversion of malaria vectors in a community with incomplete coverage of spatial repellents in the kilombero valley, tanzania.malaria elimination is unlikely to occur if vector control efforts focus entirely on transmission occurring indoors without addressing vectors that bite outdoors and outside sleeping hours. additional control tools such as spatial repellents may provide the personal protection required to fill this gap. however, since repellents do not kill mosquitoes it is unclear if vectors will be diverted from households that use spatial repellents to those that do not.201627527601
socio-economic impact of rift valley fever to pastoralists and agro pastoralists in arusha, manyara and morogoro regions in tanzania.rift valley fever (rvf) is a viral notifiable zoonotic disease primarily of domestic ruminants that causes significant socio-economic impacts. using the 2006-07 outbreak cases, this study aimed to establish the socio-economic impact of rvf and assessing knowledge, attitude and practice of livestock keepers towards controlling rvf in selected areas of tanzania. data were collected in arusha, manyara and morogoro regions using questionnaires, focus group discussions and in-depth interviews with ke ...201324255846
spatially targeting culex quinquefasciatus aquatic habitats on modified land cover for implementing an integrated vector management (ivm) program in three villages within the mwea rice scheme, kenya.continuous land cover modification is an important part of spatial epidemiology because it can help identify environmental factors and culex mosquitoes associated with arbovirus transmission and thus guide control intervention. the aim of this study was to determine whether remotely sensed data could be used to identify rice-related culex quinquefasciatus breeding habitats in three rice-villages within the mwea rice scheme, kenya. we examined whether a land use land cover (lulc) classification b ...200616684354
west nile virus in southern portugal, 2004.west nile virus (wnv) genomic rna was detected by reverse transcription-polymerase chain reaction (rt-pcr) in six out of 57 mosquito pools collected in southern portugal, during the summer of 2004, yielding an infection rate (ir) of 2.8/1,000 mosquitoes. phylogenetic analysis of a 217-nucleotide fragment of the ns5 coding region, amplified from culex pipiens s.l. and culex univittatus unfed females, demonstrated a close relationship with wnv strains circulating in the mediterranean basin (italy, ...200516417437
differential virulence of west nile strains for american crows.crow deaths were observed after west nile virus (wnv) was introduced into north america, and this phenomenon has subsequently been used to monitor the spread of the virus. to investigate potential differences in the crow virulence of different wnv strains, american crows were inoculated with old world strains of wnv from kenya and australia (kunjin) and a north american (ny99) wnv genotype. infection of crows with ny99 genotype resulted in high serum viremia levels and death; the kenyan and kunj ...200415663854
gorging response of culicine mosquitoes (diptera: culicidae) to blood fractions.although anopheline mosquitoes will ingest plasma without blood cells, culex spp. and aedes spp. require the phagostimulatory effect of blood cells; this effect can be duplicated by the addition of adenine-nucleotides to plasma. because activation of platelets released adp and atp into the plasma, they were suspected as the major source of the phagostimulant. this paper describes quantitatively the role of platelets in ingestion by aedes aegypti (l.) and culex univittatus theobald. we found that ...19938510110
experimental infection of cats and dogs with west nile virus.domestic dogs and cats were infected by mosquito bite and evaluated as hosts for west nile virus (wnv). viremia of low magnitude and short duration developed in four dogs but they did not display signs of disease. four cats became viremic, with peak titers ranging from 10(3.0) to 10(4.0) pfu/ml. three of the cats showed mild, non-neurologic signs of disease. wnv was not isolated from saliva of either dogs or cats during the period of viremia. an additional group of four cats were exposed to wnv ...200415078601
experimental infection of horses with west nile virus.a total of 12 horses of different breeds and ages were infected with west nile virus (wnv) via the bites of infected aedes albopictus mosquitoes. half the horses were infected with a viral isolate from the brain of a horse (bc787), and half were infected with an isolate from crow brain (ny99-6625); both were ny99 isolates. postinfection, uninfected female ae. albopictus fed on eight of the infected horses. in the first trial, nt antibody titers reached >1:320, 1:20, 1:160, and 1:80 for horses 1 ...200211971771
a phylogenetic approach to following west nile virus in connecticut.the 1999 outbreak of west nile (wn) virus in the northeastern united states was the first known natural occurrence of this flavivirus in the western hemisphere. in 1999 and 2000, 82 independent connecticut wn virus isolates were cultured from nine species of birds, five species of mosquitoes, and one striped skunk. nucleotide sequences obtained from these isolates identified 30 genetic changes, compared with wn-ny99, in a 921-nt region of the viral genome beginning at nucleotide position 205 and ...200111606791
first field evidence for natural vertical transmission of west nile virus in culex univittatus complex mosquitoes from rift valley province, kenya.west nile virus is a mosquito borne flavivirus endemic over a large geographic area including africa, asia, and the middle east. although the virus generally causes a mild, self-limiting febrile illness in humans, it has sporadically caused central nervous system infections during epidemics. an isolate of west nile virus was obtained from a pool of four male culex univittatus complex mosquitoes while we were conducting an investigation of rift valley fever along the kenya-uganda border in februa ...200010813479
role of dogs (canis domesticus) as hosts for african horse sickness virus.at bet dagan culicoides imicola kieffer, c. schultzei gp. (a mammal feeder), culex pipiens l. (a laboratory vector) and culex univittatus theobald were found in significantly (p < 0.05) smaller numbers near dogs than near other hosts, while phlebotomus spp. were found in significantly (p < 0.05) higher numbers in dog kennels than in other animal houses. some 400 blood meals of culicoides spp. from israel and zimbabwe were negative for canine blood. only 1 of 16 blood meals of culex pipiens caugh ...19968828119
environmental temperature on the vector competence of culex univittatus (diptera: culicidae) for west nile virus.the effects of the extrinsic incubation temperature on the vector competence of culex univittatus theobald for west nile (wn) virus were studied. a mean titer of 7.0 log10 cpd50/ml of mosquito suspension was reached in orally infected mosquitoes after 11, 15, and 16 d of incubation at 26 and 30 degrees c and at fluctuating temperatures in an outside cage (mean temperature, 23.5 degrees c), respectively. in contrast, 22 and 58 d were required to reach the same titers at 18 and 14 degrees c, respe ...19938459423
quantitative experiments on the vector capability of culex (culex) univittatus theobald with west nile and sindbis viruses. 19705451049
laboratory studies on the transmission of west nile virus by culex (culex) univittatus theobald; factors influencing the transmission rate. 19744423657
experimental assessment of the vector competence of culex (culex) neavei theobald with west nile and sindbis viruses in south africa.culex univittatus is the maintenance vector of west nile (wn) and sindbis (sin) viruses on the inland plateau of south africa and also transfers infection to man. both viruses have frequently been isolated from this mosquito and human immunity is high on the plateau. in the natal lowlands where cx univittatus is replaced by cx neavei, apparently the main vector there, immune rates are low and few isolations have been made from this species. vector competence experiments were carried out with cx ...19863024364
sindbis virus isolations from saudi arabian mosquitoes.a study in late 1979 to early 1980 was conducted to assess arbovirus activity in the eastern province of saudi arabia. from 38,245 mosquitoes collected at 3 locations, 16 isolations of sindbis virus were made: 13 from culex univittatus and one each from cx tritaeniorhynchus, cx pipiens complex, and culex spp. these isolations represent the first records of a mosquito-borne virus from the gulf of arabia and implicate cx univittatus as the principal vector. a potential risk of human diseases exist ...19852859676
comparison of three methods for determining transmission rates in vector competence studies with culex univittatus and west nile and sindbis viruses.culex univittatus mosquitoes were infected by ingesting west nile and sindbis viruses, respectively. after 13-19 days, comparative viral transmission rates were determined using 3 methods: 1) transmission to hamsters by bite, 2) in vitro transmission while feeding on suspensions in capillary tubes and 3) transmission while feeding on droplets of suspension. transmission rates were 59-100%, except for sindbis virus by droplet feeding when the rate was 9%. except for the latter, rates determined b ...19892540264
some applications of bloodmeal identifications in relation to the epidemiology of vector-borne tropical diseases.no attempt has been made to give a complete review of the value of bloodmeal identifications of haematophagous arthropods in relation to the epidemiology of disease but rather to choose certain topics of current interest. a brief review of the current techniques for bloodmeal identification is given with particular reference to recent studies on mosquitoes and sandflies using the haemagglutination inhibition test. new data on mixed feeding by anopheles gambiae (a mixture of species b and c) coll ...19751171257
an epidemiologic and serologic study of arboviruses in lake rudolf basin.an epidemiologic and serologic study of arboviruses was done in 1972 in the basin of lake rudolf. the main object of this study was to demarcate the southern limit of the yellow fever epidemic which occurred from 1959 to 1962 in southern sudan and ethiopia. other purposes were to contribute to the inventory of arboviruses and their distribution in this region. the ethnic groups were studied: the nyangatom and the dassanetch in ethiopia and the turkana in northern kenya. the results of tests on s ...1975242102
ability of selected kenyan mosquito (diptera: culicidae) species to transmit west nile virus under laboratory conditions.west nile virus (wnv) is currently active in kenya as evidenced by the detection of antibodies in birds bled as part of an avian influenza surveillance program in 2009. although wnv has been isolated from several mosquito species in kenya, no studies have ever been conducted to determine which of these species are competent vectors of this virus. therefore, we allowed kenyan mosquitoes to feed on 2- or 3-d-old chickens that had been infected with a lineage one strain of wnv 24-48 h earlier. thes ...201122238879
[the presence of the culex (culex) neavei mosquito in madagascar, its relevance in the transmission of arboviruses].a study was made of 25 male and 43 female mosquitoes belonging to the culex (culex) univittatus group, from different localities in madagascar, indian ocean. this showed that culex neavei theobald, 1906 is present on the island, at least in the tsiroanomandidy region. as demonstrated previously, cx. univitatus theobald, 1901 is also present. because of the presence of some atypical forms, firm identifications was made only in males according to the structure of the leaflet of the sub-apical lobe ...20072633711
unraveling host-vector-arbovirus interactions by two-gene high resolution melting mosquito bloodmeal analysis in a kenyan wildlife-livestock interface.the blood-feeding patterns of mosquitoes are directly linked to the spread of pathogens that they transmit. efficient identification of arthropod vector bloodmeal hosts can identify the diversity of vertebrate species potentially involved in disease transmission cycles. while molecular bloodmeal analyses rely on sequencing of cytochrome b (cyt b) or cytochrome oxidase 1 gene pcr products, recently developed bloodmeal host identification based on high resolution melting (hrm) analyses of cyt b pc ...201526230507
characterization of rabensburg virus, a flavivirus closely related to west nile virus of the japanese encephalitis antigenic group.rabensburg virus (rabv), a flavivirus with ∼76% nucleotide and 90% amino acid identity with representative members of lineage one and two west nile virus (wnv), previously was isolated from culex pipiens and aedes rossicus mosquitoes in the czech republic, and phylogenetic and serologic analyses demonstrated that it was likely a new lineage of wnv. however, no direct link between rabv and human disease has been definitively established and the extent to which rabv utilizes the typical wnv transm ...201222724010
detection of west nile virus in wild birds in tana river and garissa counties, kenya.west nile fever virus is a zoonotic arboviral infection maintained in a sylvatic cycle involving mosquito vectors and birds. it is one the arboviruses whose geographical range is expanding because of climate and land use changes that enhance the densities of mosquitoes and promote mosquito-bird-human interactions. we carried out a survey to determine the reservoirs of wnv among wild birds in tana river and garissa counties, kenya.201627881079
a spatially explicit metapopulation model and cattle trade analysis suggests key determinants for the recurrent circulation of rift valley fever virus in a pilot area of madagascar highlands.rift valley fever (rvf) is a vector-borne zoonotic disease that causes high morbidity and mortality in ruminants. in 2008-2009, a rvf outbreak affected the whole madagascar island, including the anjozorobe district located in madagascar highlands. an entomological survey showed the absence of aedes among the potential rvf virus (rvfv) vector species identified in this area, and an overall low abundance of mosquitoes due to unfavorable climatic conditions during winter. no serological nor virolog ...201425474116
how often do they meet? genetic similarity between european populations of a potential disease vector culex pipiens.species in the culex pipiens complex are common almost all over the world and represent important vectors for many serious zoonotic diseases. even if, at the moment, many of the pathogens potentially transmitted by cx. pipiens are not a problem in northern europe, they may, with increasing temperatures and changing ecosystems caused by climate change, move northward in the future. therefore, the question whether or not the cx. pipiens populations in northern europe will be competent vectors for ...201222957132
[updated inventory of mosquitoes (diptera: culicidae) of the island of la réunion, indian ocean].a literature analysis coupled with new entomological surveys conducted between 2009 and 2012 led to changes in the list of mosquito species present on the island of la réunion. using morphological criteria, orthopodomyia arboricollis is replaced by or. reunionensis. on the basis of morphometrical and genetic criteria, culex univittatus is replaced by cx. neavei. cx. poicilipes, which was already reported missing 40 years ago, has not been found again. anopheles arabiensis is confirmed as the onl ...201323681758
use of sentinel chickens to study the transmission dynamics of west nile virus in a sahelian ecosystem.during the 2003 rainy season, a follow-up survey in sentinel chickens was undertaken to assess the seasonal transmission of west nile virus (wnv) in a sahelian ecosystem: the ferlo (senegal). the estimated incidence rate in chickens was 14% (95% ci 7-29), with a very low level of transmission between july and september, and a transmission peak occurring between september and october. comparing these results with the estimate obtained from a previous transversal serological study performed on hor ...200817559695
effects of irrigation and rainfall on the population dynamics of rift valley fever and other arbovirus mosquito vectors in the epidemic-prone tana river county, kenya.rift valley fever (rvf) is a mosquito-borne viral zoonosis that is found in most regions of sub-saharan africa, and it affects humans, livestock, and some wild ungulates. outbreaks are precipitated by an abundance of mosquito vectors associated with heavy persistent rainfall with flooding. we determined the impact of flood-irrigation farming and the effect of environmental parameters on the ecology and densities of primary and secondary vectors of the rvf virus (rvfv) in an rvf-epidemic hotspot ...201628011732
biology of mosquitoes that are potential vectors of rift valley fever virus in different biotopes of the central highlands of madagascar.there were epidemic-epizootics of rift valley fever (rvf) affecting humans and cattle in madagascar in the district of anjozorobe in 2008. little is known about the role of malagasy mosquitoes in the circulation of rvf virus. therefore, we investigated the species diversity, dynamics and biology of potential rvf virus vectors in the rainforest, rainforest edge (village of anorana), and savanna biotope (village of antanifotsy) of this district between november 2008 and july 2010. we captured 56,6 ...201323802456
checklist and pictorial key to fourth-instar larvae of mosquitoes (diptera: culicidae) of saudi arabia.the kingdom of saudi arabia includes fauna from three zoogeographic regions: the afrotropical, oriental, and palaearctic regions. to study the mosquito (diptera: culicidae) fauna of these regions in saudi arabia, larval collections were made at 15 sites during 2005-2006. thirty-three species representing nine genera were found. six species, anopheles culicifacies giles s.l., anopheles subpictus grassi s.l., culex arbieeni salem, culex simpsoni theobald, culex univittatus theobald, and ochlerotat ...201121845930
gorging response of the mosquito, culex univittatus, to adenine nucleotides. 19921465152
the colonization and biology of egyptian culex univittatus (theobald). 19873572085
distribution and bionomics of egyptian culex univittatus (theobald). 19873572059
[culex univittatus theob]. 195713425717
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