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california arbovirus (la crosse) infections. iii. epidemiology of california encephalitis in minnesota.mosquitoes (eggs, larvae, and adults), small woodland animals, and residents of an area where california encephalitis is endemic were studied to elucidate the host-vector cycle of la crosse virus. elementary schoolchildren from surrounding communities and gray squirrels from another area were tested to compare the prevelence of serum antibodies to la crosse virus in areas where the disease is endemic with the prevalence of these antibodies in areas where the disease is not endemic. from 1971 to ...19763613
dirofilaria immitis and its potential mosquito vectors in central new york state.screening of 25,822 dog blood samples indicated approximately a 1% infection rate with dirofilaria immitis. dipetalonema reconditum microfilariae were found in approximately 2% of 1,876 feral dogs examined. laboratory experimentation indicated that 6 of 10 local mosquito species examined allowed successful extrinsic incubation of d immitis. indices of experimental infection indicated aedes triseriatus and anopheles quadrimaculatus were excellent hosts for d immitis, but other factors considered, ...197720828
infection rates of aedes triseriatus following ingestion of la crosse virus by the larvae.infection rates ranged from 0-2.1% in adults of aedes triseriaus reared from groups of larvae that had ingested la crosse (lac) virus (clifornia encephalitis group) at dosages of 7.0-8.3 log 10 smicld50/ml. females form orally infected larvae transmitted the virus to suckling mice. larvae that devoured carcasses of transovarially infected larvae containing 3.0 log 10 smicld 50/ml failed to become infected. ingestion by larvae of infected carcasses appears, therefore, to be unimportant as a metho ...197827990
infection rates of ascocystis-infected aedes triseriatus following ingestion of la crosse virus by the larvae.the la crosse (lac) virus infection rate of aedes triseriatus larvae that ingest lac virus does not appear to be increased by concomitant infection of larvae by the gregarine parasite, ascocystis barretti. infection rates ranged only from 0--2.6% in adult ae. triseriatus reared from groups of a. barretti-infected larvae that had ingested lac virus (california encephalitis group) at dosages of 2.0--7.7 log10 smicld50/ml. females resulting from orally infected larvae transmitted lac virus to suckl ...1979116554
herpesvirus sylvilagus in cottontail rabbits: attempted laboratory transmission by two insect species.the vector potential of the rabbit flea (cediopsylla simplex) and a mosquito (aedes triseriatus) was investigated for herpesvirus sylvilagus transmission among cottontail rabbits (sylvilagus floridanus). twelve groups of 12-50 fleas were fed on three viremic cottontails for 2-21 days before transfer to 12 susceptible rabbits. standard interrupted feeding trials employed five groups of 6-12 mosquitoes, two viremic donor cottontails anf five healthy recipients. no evidence of virus was detected fr ...1977190425
higher venereal infection and transmission rates with la crosse virus in aedes triseriatus engorged before mating.infection of colonized female aedes triseriatus by la crosse (lac) virus occurred more frequently when females were inseminated by infected males after the females engorged blood (49% of 39) than when mating took place before engorgement (4% of 554). salivary transmission of lac virus to mice also was more frequent in females venerally infected after engorgement on a normal mouse (35% of 34) than in females mated before engorgement (2% of 49). lac virus was transovarially transmitted by 40% of 1 ...1979484771
aedes triseriatus and la crosse virus: lack of infection in eggs of the first ovarian cycle following oral infection of females.la crosse (lac) virus filial infection rates were 0% for 279 first ovarian cycle larvae, 43% for 380 second ovarian cycle larvae, and 58% for 363 third ovarian cycle larvae from orally infected mosquitoes representing 14 wisconsin populations of aedes triseriatus. lac virus was not detected in 72 pools representing 2,250 first ovarian cycle larvae, while 35 pools and 16 pools each containing 30 second and third ovarian cycle larvae, respectively, were all positive for lac virus. similar results ...1979484772
vertical transmission of la crosse virus (california encephalitis group): transovarial and filial infection rates in aedes triseriatus (diptera: culicidae). 1977609074
venereal transmission of la crosse virus from male to female aedes triseriatus.horizontal transmission of la crosse (lac) arbovirus in colonized aedes triseriatus was first observed in mating cages. lac antigen was visualized by fluorescent antibody technique in multiple organs of 5 (2.5% of 198 females dissected after contact in mating cages with males, with a transovarial infection rate of 31%. venereal transmission of lac virus was demonstrated by limited contact induced mating. antigen was detected in bursal contents of 35 (53%) of 66 females dissected within 24 h afte ...1978626272
tropisms of la crosse virus in aedes triseriatus (diptera: culicidae) following infective blood meals. 1978633286
delineation of la crosse virus in developmental stages of transovarially infected aedes triseriatus.the tropisms and development of la crosse (lac) virus in stages of transovarially infected aedes triseriatus were studied with fluorescent antibody (fa) stained dissected organs and titrations of individual arthropods in suckling mice. viral antigen was detected by fa in 95 of 387 dissected larvae, pupae, and adults. in larvae highest levels of fluorescence were detected in the alimentary tract, followed by ganglia, malpighian tubule, muscle, and other tissues. no specific organs or germ layer-d ...1976779503
isolates of california encephalitis (la crosse) virus from field-collected eggs and larvae of aedes triseriatus: identification of the overwintering site of california encephalitis.california encephalitis is caused primarily by la crosse virus, a mosquito-borne agent of which the vector is the mosquito aedes triseriatus. once la crosse virus has been detected in a given geographical area, observations in the same area during subsequent seasons usually have revealed continuing presence of the virus. field studies were conducted around the homes of children who had had california encephalitis in an effort to define the mechanism by which the virus survived the winter. eggs a ...1975805813
venereal transmission of la crosse (california encephalitis) arbovirus in aedes triseriatus mosquitoes.veneral transmission of la crosse virus by males of aedes triseriatus was demonstrated. la crosse virus was detected in the bursa of females after induced copulation, and disseminated infection was shown to occur occasionally. since males of aedes triseriatus have transovarial filial infection rates similar to those of females and can repeatedly mate, veneral transmission may be an important supplement to other natural endemic maintenance mechanisms.1977850794
viremia and antibody response to la crosse virus in sentinel gray squirrels (sciuris carolinensis) and chipmunks tamias striatus).six isolates of la crosse (lac) virus were obtained from sentinel gray squirrels (sciuris carolinensis) and four from sentinel chipmunks (tamias striatus) in an endemic area. viremia titers were measured by plaquing on vero cells. antibody responses of the animals were measured by a microneutralization test employing four california group viruses: lac, snowshoe hare (ssh), trivittatus, and jamestown canyon. in both species lac antibody titers peaked at approximately 21 days and were still detect ...1977889022
aedes triseriatus and la crosse virus: geographic variation in vector susceptibility and ability to transmit.in laboratory tests, 20 strains of aedes triseriatus differed widely in response to la crosse virus. infection rates ranged from 40% to 93%, and rate of transmission ranged from 20% to 90%. a control strain, tested in seven different trials, showed no significant variation in susceptibility (71--77%) or transmission ability (54--68%). a distinct geographic pattern was evident. the susceptibility and transmission rates of strains from areas where la crosse virus is endemic were lower than that of ...1977907059
transovarial transmission of lacrosse virus in aedes triseriatus.as part of a continuing investigation on the ecology of lacrosse virus in wisconsin, field and laboratory studies were conducted to explore the possibility that the virus is transmitted transovarially in a. triseriatus mosquitoes. in laboratory experiments, a. triseriatus mosquitoes were infected by ingesting lacrosse virus in defibrinated blood. lacrosse virus was recovered from f1 eggs, larvae, and adults that originated from the infected parent mosquitoes. in a subsequent field study aimed at ...19751072592
emergence of la crosse virus from endemic foci. fluorescent antibody studies of overwintered aedes triseriatus.the frequency and distribution of la crosse (lac) virus overwintering in aedes triseriatus diapause eggs were studied during 1974 by following 64 tree-hole oviposition sites in four enzootic hardwood forest areas. a direct fluorescent antibody technique, adapted for detection of lac virus in individual mosquitoes, proved to be a rapid, reliable and economical tool for ascertaining true field infection rates. virus was found in larvae from each of the four study areas before the seasonal emergenc ...19751098500
isolation of la crosse virus (california encephalitis group) from the chipmunk (tamias striatus), an amplifier host.la crosse (lac) virus was isolated from the blood of seven chipmunks (tamias striatus) captured during the summer of 1970 in southwestern wisconsin. with the exception of the original isolate obtained from human brain after fatal encephalitis, these represent the first known isolations of lac virus from a naturally infected free-living vertebrate. the chipmunks were trapped and periodically recaptured in two study areas where 59 chipmunks became infected and developed neutralizing antibody durin ...19751106233
genomic and biologic analyses of snowshoe hare virus field and laboratory strains.low-passage field strains of snowshoe hare (ssh) virus (bunyaviridae), the prototype ssh virus (originally isolated in montana), and la crosse (lac) virus were compared serologically by plaque-reduction neutralization (prnt) and molecularly by oligonucleotide fingerprinting (onf). the prnt and onf results confirmed the identity of the field strains, although some differences in the fingerprints were observed. we have examined the rna genome variability in the two field and three laboratory strai ...19921599046
vector competence of aedes hendersoni (diptera: culicidae) for la crosse virus: lack of impaired function in virus-infected salivary glands and enhanced virus transmission by sporozoite-infected mosquitoes.previous research has shown aedes hendersoni cockerell to be an incompetent vector of la crosse (lac) virus because of a salivary gland escape (sge) barrier; that is, the salivary glands are infected but the mosquito fails to transmit the virus orally. intradermal probing behavior and ability to locate blood were studied in infected mosquitoes as indicators of salivary gland impairment to determine if the sge barrier was due to virus-induced pathology of the salivary glands. no evidence of saliv ...19921625297
vertical and venereal transmission of california group viruses by aedes triseriatus and culiseta inornata mosquitoes.aedes triseriatus and culiseta inornata mosquitoes were compared in their ability to transmit vertically la crosse (lac) and snowshoe hare (ssh) viruses. lac virus was transovarially transmitted by 53% of ae. triseriatus, the natural vector, and by 22% of cs. inornata mosquitoes. ssh virus was transovarially transmitted by 89% of cs. inornata, a proposed natural vector, and by 29% of ae. triseriatus. a genetic approach, using lac, ssh, and lac/ssh reassortant viruses was then used to elucidate v ...19911686962
aedes triseriatus (diptera: culicidae) and la crosse virus. iv. nutritional deprivation of larvae affects the adult barriers to infection and transmission.groups of aedes triseriatus (say) were reared either as nutritionally deprived (two regimens) or well fed (one regimen) throughout larval development, and the vector competence of resulting small, normal, and large females was assessed for la crosse virus. when fed a high dose of virus (4.6 log10/0.025 ml in vero cell culture), 90% of small ae. triseriatus females transmitted la crosse virus to suckling mice compared with 70% of normal and 42% of large females. among small females, 100% had diss ...19911875364
effect of body size on the vector competence of field and laboratory populations of aedes triseriatus for la crosse virus.aedes triseriatus females collected as pupae from 2 tireyards and one woodlot were tested for susceptibility to la crosse virus infection and ability to transmit the virus to suckling mice. rates of disseminated infection and oral transmission were inversely correlated with mean body size. the smallest population developed disseminated infections and transmitted virus at significantly higher rates than the 2 larger populations. adults derived from f1 eggs of the largest and smallest populations ...19911895074
reassortment of la crosse and tahyna bunyaviruses in aedes triseriatus mosquitoes.experiments were conducted to determine if la crosse (lac) and tahyna (tah) viruses reassort in aedes triseriatus mosquitoes and to determine the genotypic frequencies of viruses selected by in vivo vector interactions. a molecular hybridization technique was used to analyze progeny viruses. probes specific for the la crosse l, m and s segments (plac4.16: lac l rna; plac4.27: lac m rna; plac4c-26: lac s rna) were used to determine the parental origin of the progeny rna segments. following infect ...19911950171
chromosomal localization and copy number of 18s + 28s ribosomal rna genes in evolutionarily diverse mosquitoes (diptera, culicidae).in situ hybridization using 3h-labeled 18s and 28s ribosomal dna (rdna) probes from aedes albopictus was performed on the mitotic chromosomes of 20 species of mosquitoes belonging to 8 genera of subfamilies culicinae and anophelinae. in all but one species examined, the rdna family was localized to a single chromosome per haploid genome. aedes triseriatus was the only exception, with the rdna cistrons present on chromosome 1 and on chromosome 3. the ribosomal rna genes were located on chromosome ...19902093704
heterologous reassortment of bunyaviruses in aedes triseriatus mosquitoes and transovarial and oral transmission of newly evolved genotypes.aedes triseriatus mosquitoes were orally infected with two different california serogroup bunyaviruses (la crosse and snowshoe hare viruses) and high frequency reassortment occurred in these mosquitoes. increased viral replication and subsequent gene segment reassortment was noted in the ovaries of mosquitoes that had ingested multiple blood-meals. to determine whether newly generated reassortant viruses could be transmitted transovarially to progeny mosquitoes, adult female mosquitoes were inoc ...19902345365
spatial distribution of aedes triseriatus eggs in a site endemic for la crosse encephalitis virus.egg laying behavior in aedes triseriatus was studied in an oak woodlot endemic for la crosse encephalitis virus in southwestern wisconsin. daily counts from oviposition traps allowed the calculation of spatial distribution parameters for eggs during 1988. egg distribution along an ellipsoidal transect of 25 traps was clumped with some traps being more attractive to ovipositing female ae. triseriatus than others. females were estimated to deposit a mean of 31 +/- 9.8 eggs per oviposition.19902370533
genomic stability of la crosse virus during vertical and horizontal transmission.we have used ribonuclease t1 oligonucleotide fingerprint analysis to study genomic stability of la crosse virus (bunyaviridae) during vertical and horizontal transmission in the laboratory. no rna genomic changes were detected in vertebrate cell culture-propagated virus isolated (following ingestion and replication) from the natural host, aedes triseriatus. genomic changes were not detected during transovarial passage of the virus through two generations of mosquitoes, nor were changes detected ...19892512895
midgut and salivary gland barriers to la crosse virus dissemination in mosquitoes of the aedes triseriatus group.vector competence for la crosse virus (lacv) was compared for four species in the aedes (protomacleaya) triseriatus group: ae. triseriatus (say), ae. hendersoni cockerell, ae. zoosophus dyar and knab and ae. brelandi zavortink (diptera: culicidae). rates of replication and dissemination of virus in the mosquito hosts were compared and rates of oral transmission of virus to suckling mice were determined. barriers to virus dissemination which limited the ability of each species to transmit virus w ...19892519653
recently introduced aedes albopictus in the united states: potential vector of la crosse virus (bunyaviridae: california serogroup).a population of aedes albopictus collected in 1986 in harris county, texas, was evaluated for its vector competence with 4 california serogroup viruses (jamestown canyon, keystone, la crosse and trivittatus). rates of midgut infection, dissemination of virus beyond the midgut and oral transmission to suckling mice were markedly different for the 4 viruses in a pattern representative of the antigenic relationships known for the california serogroup. only la crosse virus was shown to be efficientl ...19892584976
replication and dissemination of la crosse virus in the competent vector aedes triseriatus and the incompetent vector aedes hendersoni and evidence for transovarial transmission by aedes hendersoni (diptera: culicidae).the time course and pattern of the replication and dissemination of la crosse virus was studied in orally infected aedes triseriatus (say) and ae. hendersoni cockerell. development of la crosse virus was approximately the same in both species when plaque assay titers of intact mosquitos or dissected tissues were compared. the mosquitoes were equally susceptible to infection; all ae. hendersoni and 99% of the ae. triseriatus tested showed detectable midgut infections. virus was first detected in ...19892585454
california serogroup virus infections in wisconsin domestic animals.a serologic survey and experimental virus transmission studies were done to assess the role of domestic animals as amplifier hosts of la crosse (lacv) and jamestown canyon (jcv) viruses. serum from 319 cows, 88 dogs, 122 equines, 47 swine, 10 goats, and 4 cats were tested for neutralizing antibody to lacv, jcv, trivittatus (tvtv), and snowshoe hare (sshv) viruses. antibody prevalences of lacv, tvtv, and sshv were less than 10% in all species. antibody to jcv was detected in all species except ca ...19883189702
adult body size and survivorship in a field population of aedes triseriatus.aedes triseriatus pupae, host-seeking, and ovipositing females were collected at a southern wisconsin site endemic for la crosse encephalitis virus. the host-seeking and ovipositing females were age-graded by the detinova and polovodova techniques, respectively. wing lengths were determined for all mosquitoes. wing lengths of the mosquitoes collected as pupae were predicted from pupal weight by a simple regression equation. there was significant seasonal variation in body size of adult females, ...19883193107
interference to oral superinfection of aedes triseriatus infected with la crosse virus.aedes triseriatus orally infected with a temperature-sensitive mutant of la crosse virus were, at predetermined times post-infection, orally challenged with wild type la crosse or tahyna virus. most mosquitoes challenged with wild type la crosse virus within 24 hr of ingestion of the temperature-sensitive virus became superinfected. in contrast, the majority of mosquitoes challenged at 72 hr were resistant to superinfection. mosquitoes challenged at 7 days or thereafter were refractory to superi ...19883354775
limited efficacy of levamisole against adults of dirofilaria immitis in a dog.a dog with chronic dirofilariasis (dirofilaria immitis) was given 15 doses of 12 or 24 mg of levamisole/kg of body weight in 6 treatments within 96 days. concentration of microfilariae in the blood was determined before and after treatment, and aedes triseriatus mosquitoes were fed on the dog 1 to 5 days after each treatment and examined for d immitis larvae. several adult worms were recovered from the dog 160 days after the end of the treatments.19883410792
absence of la crosse virus in the presence of aedes triseriatus on the delmarva peninsula.between 1980 and 1984, field studies were conducted in 2 areas on the delmarva peninsula to identify the presence of la crosse (lac) virus. ovitraps were used to collect eggs of aedes triseriatus complex mosquitoes. no virus was obtained from 969 pools containing 22,370 adult mosquitoes reared from eggs. only 1 of 143 raccoon serum samples had neutralizing antibody to lac virus; 36 sentinel domestic goats, and 99 other wild mammal serum samples were negative. the apparent absence of lac virus ma ...19863507467
aedes triseriatus and la crosse virus: similar venereal infection rates in females given the first bloodmeal immediately before mating or several days after mating.venereal infection rates of aedes triseriatus females mated to males transovarially infected with la crosse virus were determined in 6 cage-mating trials. in trials 1-4, venereal infection rates averaged 46% and 45% in f2 females bloodfed 6-8 hr before and 7 days after exposure, respectively, to transovarially-infected males. these rates were similar to rates previously reported only in mosquitoes receiving a bloodmeal 6-8 days prior to mating. lower rates (24%-31%) were obtained using f4 and f7 ...19873578660
a g1 glycoprotein epitope of la crosse virus: a determinant of infection of aedes triseriatus.arthropod-borne viruses (arboviruses) have specific vector-vertebrate host cycles in nature. the molecular basis of restriction of virus replication to a very limited number of vector species is unknown, but the present study suggests that viral attachment proteins are important determinants of vector-virus interactions. the principal vector of la crosse (lac) virus is the mosquito aedes triseriatus, and lac virus efficiently infects the mosquito when ingested. however, a variant (v22) of lac vi ...19873810159
lack of adverse effect of transovarially acquired la crosse virus infection on the reproductive capacity of aedes triseriatus (diptera: culicidae). 19853841159
influence of defensive behavior of eastern chipmunks and gray squirrels (rodentia: sciuridae) on feeding success of aedes triseriatus (diptera: culicidae). 19863950920
fine structure and development of pilosporella chapmani (microspora: thelohaniidae) in the mosquito, aedes triseriatus (say).new information on the life cycle and fine structure of pilosporella chapmani, a microsporidium of the mosquito aedes triseriatus, is presented. pilosporella chapmani is shown to have two sporulation sequences, one of them being involved in transovarial transmission. one sequence, involving meiosis and production of a moniliform sporogonial plasmodium, occurs in the larval fat body, resulting in eight uninucleate, spherical, and fully developed spores. the other occurs in oenocytes of adult mosq ...19863959008
experimental la crosse virus infection of red fox (vulpes fulva), raccoon (procyon lotor), opossum (didelphis virginiana), and woodchuck (marmota monax).susceptibility to infection, resulting viremia and antibody responses, and potential to provide infectious blood meals for aedes triseriatus were determined and compared for the red fox (vulpes fulva), raccoon (procyon lotor), and opossum (didelphis virginiana) exposed to la crosse (lac) virus transmitted by mosquitoes, ae. triseriatus. woodchucks (marmota monax) were infected with lac virus by needle and syringe. all 5 red foxes became viremic following the bite of a single lac virus-infected f ...19854003669
la crosse viremias in juvenile, subadult and adult chipmunks (tamias striatus) following feeding by transovarially-infected aedes triseriatus.viremia and antibody responses to la crosse (lac) virus were determined for juvenile, subadult and adult chipmunks (tamias striatus). viremia was detected in 16 of 16 juveniles, 13 of 17 subadults and 21 of 29 adults fed upon by transovarially (to)-infected aedes triseriatus. mean viremia titers for juvenile, subadult and adult chipmunks responding to lac infection were 3.0, 2.9 and 3.2 log10smicld50/0.025 ml, respectively. the average duration of viremia with lac virus was 2.4, 2.3 and 2.4 days ...19854003670
oral infection and transmission of la crosse virus by an enzootic strain of aedes triseriatus feeding on chipmunks with a range of viremia levels.the susceptibility of aedes triseriatus to oral infection with la crosse (lac) virus resulting from feeding on chipmunks with viremia titers of 0.6 to 4.6 log10smicld50/0.025 ml was determined. results indicated that viremia titers must exceed 3.2 log10smicld50/0.025 ml before a significant proportion (greater than or equal to 50%) of mosquitoes are infected and capable of transmitting lac virus. mosquitoes which fed on chipmunk blood-lac virus mixtures through a membrane feeder had significantl ...19854037186
evolution of bunyaviruses by genome reassortment in dually infected mosquitoes (aedes triseriatus).aedes triseriatus mosquitoes became dually infected after ingesting two mutants of lacrosse (lac) virus simultaneously or after ingesting, by interrupted feeding, the two viruses sequentially within a 2-day period. after 2 weeks of incubation, approximately 25 percent of the vectors contained new virus genotypes as the result of rna segment reassortment. new viruses were transmitted when the mosquitoes fed on mice. viruses ingested more than 2 days after the initial infecting virus did not cause ...19854048949
local variation in blood feeding by aedes triseriatus and aedes hendersoni (diptera: culicidae). 19854078847
diurnal biting activity of aedes triseriatus complex (diptera: culicidae) in a focus of la crosse virus transmission. 19854078852
observations on a natural cycle of la crosse virus (california group) in southwestern wisconsin.ecological studies were conducted to document the role of the eastern chipmunk (tramias striatus) as a vertebrate host for la crosse (lac) virus in nature during late summer when aedes triseriatus mosquitoes are most abundant. movement, home range and density of chipmunk populations were determined by trap mark and recapture techniques on grid study areas. the temporal distribution of a. triseriatus was estimated by use of oviposition traps. passive antibodies were found in spring-born juveniles ...19744451237
isolation of la crosse virus from field collected aedes triseriatus larvae. 19744817670
overwintering of la crosse virus in aedes triseriatus. 19744847044
experimental infection of chipmunks and squirrels with la crosse and trivittatus viruses and biological transmission of la crosse virus by aedes triseriatus. 19725050096
eastern equine encephalomyelitis virus: an electron microscopic study of aedes triseriatus (say) salivary gland infection. 19715543265
detection of eastern equine encephalomyelitis virus and highlands j virus antigens within mosquito pools by enzyme immunoassay (eia). i. a laboratory study.enzyme immunoassays (eias) producing either chromogenic or fluorogenic end products were developed and evaluated for detection of eastern equine encephalomyelitis (eee) and highlands j (hj) viruses in pools of aedes triseriatus mosquitoes. overnight incubation of the mosquito samples in the eia significantly enhanced the sensitivity of the test. both the eee and hj eias were sensitive, readily detecting one infected mosquito in a pool with 99 noninfected, and specific, distinguishing homologous ...19846091470
studies on selection of lacrosse virus variants by natural vertebrate hosts and vector mosquitoes.the effect of passage in natural hosts on lacrosse virus plaque size, mouse neurovirulence, and plaquing efficiency was studied. seven field strains, as previously unpassaged naturally infected aedes triseriatus suspensions, were inoculated into chipmunks tamias striatus and thence into colonized ae. triseriatus. the prototype strain, with seven prior laboratory passages, was also passed through the same natural host species. the field strains changed in neurovirulence and plaque size at various ...19816113754
[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
sensitivity to carbon dioxide in mosquitoes infected with california serogroup arboviruses.ten species of mosquitoes became sensitive to co2 following intrathoracic (i.t.) inoculation of california encephalitis (ce) virus. these included field-collected aedes melanimon, aedes nigromaculis and culiseta incidens and laboratory-colonized strains of aedes dorsalis, aedes triseriatus, anopheles freeborni, culex peus, culex pipiens pipiens, culex pipiens quinquefasciatus and culex tarsalis. another california serogroup virus, jerry slough (= jamestown canyon) (js), also induced co2 sensitiv ...19826122383
interference between bunyaviruses in aedes triseriatus mosquitoes.inhibition of the replication of alternate california serogroup bunyaviruses in aedes triseriatus mosquitoes has been observed for mosquitoes previously infected with la crosse (lac) virus. by contrast, prior infection of mosquitoes with lac virus did not interfere significantly with the subsequent infection and replication of guaroa bunyavirus (bunyamwera serogroup), or heterologous viruses such as west nile flavivirus, or vesicular stomatitis rhabdovirus.19836305019
biology of aedes triseriatus: some factors affecting control. 19836346339
aedes triseriatus: vector biology in relationship to the persistence of la crosse virus in endemic foci. 19836346342
evaluation of immunofluorescence and cell culture techniques for detecting la crosse virus infection in individual aedes triseriatus (diptera: culicidae). 19836352944
effects of gregarine parasites on the development of dirofilaria immitis in aedes triseriatus (diptera: culicidae). 19836402598
oral and transovarial transmission of la crosse virus by aedes atropalpus.a recently colonized strain of aedes atropalpus was shown to be equally susceptible to oral infection with la crosse (lac) virus as the natural vector, aedes triseriatus. la crosse virus was shown to replicate and persist at high titers in orally infected ae. atropalpus. in addition, orally infected females transmitted virus efficiently to suckling mice by mosquito bite. transovarial transmission of lac virus was demonstrated by recovery of virus from larval progeny after parental females were i ...19846476218
conditions for increased insemination rates in caged aedes triseriatus (diptera: culicidae) reared from field-collected eggs.primarily in order to facilitate future studies on venereal transmission of la crosse encephalitis virus by aedes triseriatus, tests were conducted to identify conditions that maximize insemination rates in caged populations of ae. triseriatus derived from field-collected eggs. all tests were conducted at 21 degrees c +/- 1 degree c, which is approximately the mean temperature during july and august in southwestern wisconsin where la crosse virus is endemic. non-bloodfed females exposed on their ...19846476220
dispersion of gravid aedes triseriatus (diptera: culicidae) from woodlands into open terrain. 19846492082
the replication of two california serogroup viruses in a cell line from the mosquito aedes triseriatus (diptera: culicidae). 19846502609
quantitation of la crosse virus in venereally infected aedes triseriatus.the replication of two strains of la crosse (lac) virus, prototype and an unpassaged field isolate, was followed in intrathoracically inoculated male and venereally infected female aedes triseriatus mosquitoes. the venereal infection rate following induced mating was 13.6% of 44 females inseminated by males inoculated with prototype virus, and 26.3% of 38 females inseminated by males inoculated with an unpassaged field strain. the males consistently contained concentrations of virus in reproduct ...19836625068
lower rates of oral transmission of la crosse virus by aedes triseriatus venereally exposed after engorgement on immune chipmunks.transmission rates of la crosse (lac) virus observed in aedes triseriatus females that had engorged on chipmunks with antibody to lac and had been mated by infected males 5-11 days later (24%, 69/288) were 40% lower than in those fed on chipmunks without antibody (38%, 112/293). similar results were obtained in three separate trials using males infected 1) by inoculation with prototype lac virus, 2) transovarially with a field strain, or 3) transovarially with the field strain following passage ...19836650741
a variant of la crosse virus attenuated for aedes triseriatus mosquitoes.a plaque-purified variant was cloned from prototype la crosse (lac) virus. this variant (pp-31) was lethal to suckling mice by the intracerebral route, produced "wild-type" plaques in vero and bhk-21 cells, and grew to high titers (greater than 10(7) pfu/ml) in suckling mice and in cell culture. the variant was able to orally infect the vector, aedes triseriatus; however, it was unable to escape infected midgut cells and disseminate to secondary target organs. large, atypical, focal accumulation ...19836650742
transmission of dengue virus by orally infected aedes triseriatus.transmission of dengue type 1 was demonstrated for 3 strains of aedes triseriatus mosquitoes after oral infection. rates of infection were similar to those observed in a control strain of aedes aegypti. three additional species belonging to the subgenus protomacleaya (aedes brelandi, aedes hendersoni, and aedes zoosophus) were also susceptible to oral infection with dengue type 1 virus but transmission could not be demonstrated although virus was detected in the salivary glands of infected mosqu ...19836650743
experimental transovarial transmission of st. louis encephalitis virus by culex and aedes mosquitoes.colonized and field-collected female culex tarsalis, infected with st. louis encephalitis, (sle) virus by intrathoracic inoculation or by feeding on a viremic host, transmitted virus to their f1 adult and/or larval progeny when reared at 18(+/- 1) degree c but not when reared at 27(+/- 1) degrees c. the minimal infection rates (mir) for different populations of cx. tarsalis ranged from 1:32 to less than 1:250 (mean = 1:121) for larval progeny and from 1:32 to less than 1:1, 989 (mean = 1:1,571) ...19846696174
aedes triseriatus (diptera: culicidae) and la crosse virus. iii. enhanced oral transmission by nutrition-deprived mosquitoes. 19846747998
molecular basis of bunyavirus transmission by mosquitoes: role of the middle-sized rna segment.in an examination of the molecular basis of oral transmission of bunyaviruses by mosquitoes., la crosse (lac), snowshoe hare (ssh), and lac-ssh reassortant viruses were compared in their ability to be transmitted to laboratory mice by the natural mosquito vector of lac virus, aedes triseriatus. both lac virus and the reassortment viruses containing the middle-sized (m) segment from the lac parent were efficiently transmitted. in contrast, ssh virus and reassortment viruses containing the m rna f ...19816781068
persistence of la crosse virus (california encephalitis serogroup) in north-central illinois.la crosse (lac) virus was first isolated in illinois from a pool of 50 female aedes triseriatus mosquitoes collected in july 1976, in peoria heights. from 1978 through 1981, 27 strains (11 from males and 16 from females) of lac virus were recovered from 888 pools containing 22,021 adult a. triseriatus mosquitoes from the same study area. these mosquitoes had developed from larvae and pupae collected from 50 individually identified treeholes. of the 14 trees that yielded lac virus-positive mosqui ...19836824122
effect of host blood source on the gonotrophic cycle of aedes triseriatus.host blood source was found to affect both the fecundity and the duration of te gonotrophic cycle of aedes triseriatus. mosquitoes were fed on restrained deer, chipmunks, squirrels, humans and suckling mice. results showed that mosquitoes fed on chipmunks or squirrels, the major la crosse virus vertebrate amplifier hosts, had greater fecundity but longer gonotrophic time intervals (approximately 2 more days per ovarian cycle) than mosquitoes fed on deer, which is a non-amplifier species. results ...19836824124
control of aedes triseriatus in la crosse, wisconsin. 19836867040
molecular basis of bunyavirus per os infection of mosquitoes: role of the middle-sized rna segment.the molecular basis of bunyavirus per os infection of mosquitoes was determined; la crosse (lac), snowshoe hare (ssh), and lac-ssh reassortment viruses were compared for their ability to infect aedes triseriatus, the natural vector of the lac virus. the viruses were comparable in their ability to infect midgut cells; 115 of 117 (98%) mosquitoes ingesting viruses containing the lac middle-sized rna segment and 92/100 (92%) of mosquitoes ingesting viruses containing the ssh middle-sized rna segmen ...19826951175
bloodmeal sources of aedes triseriatus and aedes vexans in a southern wisconsin forest endemic for la crosse encephalitis virus.the micro enzyme-linked immunosorbent assay (elisa) was used to specifically identify bloodmeal sources of aedes triseriatus say and aedes vexans meigen collected at a site endemic for la crosse (lac) encephalitis virus. deer were the source of 65% of ae. triseriatus and 94% of aedes vexans bloodmeals, respectively. chipmunks and tree squirrels, which are considered to be the major vertebrate amplifying hosts of lac virus, were the sources of 8% and 16%, respectively, of the bloodmeals of ae. tr ...19827072901
la crosse virus infection and disease in western north carolina.active surveillance for la crosse infection from 1977 to 1979 revealed 12 laboratory documented cases in children from the cherokee reservation and nearby areas of western north carolina. the annual rate of hospitalization with la crosse virus was isolated from two of 34 pools of male and one of 34 pools of female aedes triseriatus mosquitoes reared from larvae collected around the residences of reservation children who had been hospitalized with encephalitis. the occurrence of the recent cases, ...19827081548
variation of la crosse virus filial infection rates in geographic strains of aedes triseriatus (diptera: culicidae). 19827086859
natural la crosse virus infection in the red fox (vulpes fulva), gray fox (urocyon cinereoargenteus), raccoon (procyon lotor), and opossum (didelphis virginiana).natural infection of sentinel red foxes (vulpes fulva) and free-ranging red foxes, gray foxes (urocyon cinereoargenteus) and raccoons (procyon lotor) with la crosse (lac) virus was demonstrated. one isolate of lac virus was obtained from a sentinel red fox in an enzootic area. the viremia titer of the lac virus-infected red fox was above the threshold of infection for aedes triseriatus mosquitoes. antibody responses were measured by the microneutralization test employing four california group vi ...19817258486
aedes triseriatus (diptera: culicidae) and la crosse virus. ii. modification of mosquito feeding behavior by virus infection. 19807365753
the expression of chloramphenicol acetyltransferase in mosquitoes and mosquito cells using a packaged sindbis replicon system.sindbis (sin) replicon virus was used to express chloramphenicol acetyltransferase (cat) in aedes albopictus (c6/36) cells and aedes triseriatus mosquitoes. rna transcribed in vitro from a sin replicon plasmid (psinrep5/cat) and from sin virus helper constructs (pdh-eb or pdh(26s)5'sin) was coelectroporated into bhk-21 cells to generate replicon viruses, designated rep5/cat/eb and rep5/cat/26s. c6/36 cells infected with rep5/cat/eb or rep5/cat/26s virus at a multiplicity of infection of 3, expre ...19957498436
larvicidal activity of the entomopathogenic fungus tolypocladium cylindrosporum (deuteromycotina: hyphomycetes) on the mosquito aedes triseriatus and the black fly simulium vittatum (diptera: simuliidae).laboratory bioassays evaluated the pathogenicity of the entomopathogenic fungus tolypocladium cylindrosporum against aedes triseriatus. all larval instars were found to be susceptible at temperatures from 18 to 25 degrees c. blastoconidia were more virulent than conidia. mortality was proportional to exposure time in assays using blastoconidia. blastoconidia and exposure time appear to be a more adequate method for bioassay of t. cylindrosporum virulence than the standard procedure of using coni ...19947707051
host range tests with edhazardia aedis (microsporida: culicosporidae) against northern nearctic mosquitoes.twelve species of northern nearctic mosquitoes representing five genera (aedes, anopheles, culex, culiseta, and psorphora) were bioassayed for susceptibility to edhazardia aedis, an exotic, heterosporous, microsporidian parasite of the yellow fever mosquito, aedes aegypti. infections were achieved in aedes atropalpus, aedes triseriatus, and aedes vexans following oral ingestion of uninucleate spores obtained from patently infected ae. aegypti larvae. the microsporidium underwent normal vegetativ ...19947914904
serotonin depletion affects blood-feeding but not host-seeking ability in aedes triseriatus (diptera: culicidae).the host-seeking and blood-feeding abilities of aedes triseriatus (say) were evaluated after treatment with the amine depleting drugs alpha-methyl-tyrosine (amt) and alpha-methyl-tryptophan (amtp). high-performance liquid chromatography with electrochemical detection (hplced) was used to demonstrate that amtp depleted serotonin levels, whereas amt reduced dopamine levels. the host-seeking ability (evaluated with an olfactometer) of ae. triseriatus was not altered by treatment with either amt or ...19947932607
salivary vasodilators of aedes triseriatus and anopheles gambiae (diptera: culicidae).salivary vasodilators of aedes aegypti (l.) and anopheles albimanus (wiedemann) were characterized previously as a tachykinin peptide and a catechol oxidase/peroxidase activity, respectively. to verify whether these two different vasodilators also were found in other distantly related members of each mosquito genus, we characterized the vasodilators from a. triseriatus and a. gambiae. a. triseriatus salivary gland homogenates produced a reversible, endothelium dependent vasorelaxation of rabbit ...19947966179
the expression of chloramphenicol acetyltransferase in aedes albopictus (c6/36) cells and aedes triseriatus mosquitoes using a double subgenomic recombinant sindbis virus.genomic rna was transcribed in vitro from the double subgenomic recombinant sindbis (sin) virus expression vector, pte/3'2j/cat, and transfected into bhk-21 cells to generate recombinant virus stocks. te/3'2j/cat virus was used to infect c6/36 (aedes albopictus) cells and adult female aedes triseriatus. when c6/36 cells were infected with te/3'2j/cat virus at a multiplicity of infection (moi) of greater than 20, 100% of the cells expressed cat. the number of cat polypeptides expressed per cell a ...19948111422
distributional records for aedes mosquitoes from the u.s. air force ovitrapping program-1992.during 1992, ovitrapping to sample populations of container-breeding aedes was conducted at 28 u.s. air force installations in north america. aedes albopictus was collected at 19 installations. the collections of ae. albopictus at goodfellow air force base (afb), tx, and moody afb, ga, represent new records for tom green and lowndes counties, respectively. six installations were positive for ae. aegypti; 13 were positive for aedes triseriatus.19938245948
isolation of jamestown canyon and snowshoe hare viruses (california serogroup) from aedes mosquitoes in western massachusetts.three isolates of jamestown canyon virus and one isolate of snowshoe hare virus (california serogroup) were obtained from adult aedes females collected in western massachusetts in 1982. jamestown canyon virus was isolated from aedes abserratus/punctor once, and from aedes intrudens twice. snowshoe hare virus was isolated from aedes stimulans group mosquitoes. la crosse encephalitis (lac) virus was not isolated from 1,552 adult aedes triseriatus, nor from 22,557 aedes triseriatus larvae. however, ...19938350066
establishment and characterization of three cell lines from aedes triseriatus (diptera: culicidae).three cell lines (a.t. grip-1, 2, and 3) were established from aedes triseriatus (say) embryonated eggs or neonate larvae and their morphology, growth, karyotype, and isozyme pattern were studied. the isozyme alleles observed in the 3 cell lines also were found in adults of the original mosquito colony. each cell line differed in enzymatic, morphological, and karyotypical patterns. la crosse encephalitis (lac) and snowshoe hare (ssh) viruses, members of the california encephalitis virus group, w ...19958551501
la crosse viremias in white-tailed deer and chipmunks exposed by injection or mosquito bite.to further understand the role of wild mammals in the maintenance of la crosse virus (lacv) in nature, we investigated the effects of inoculation method and virus source on the duration and amplitude of lacv viremia in vertebrate hosts. earlier work suggested that deer are not sufficiently susceptible to lacv to play an important role in its maintenance. we re-evaluated the susceptibility of deer since subsequent studies showed that they constitute 65% of aedes triseriatus blood meals, and thus ...19968615443
the midgut bacterial flora of wild aedes triseriatus, culex pipiens, and psorophora columbiae mosquitoes.the midgut bacterial flora of wild-caught aedes triseriatus, culex pipiens, and psorophora columbiae mosquitoes was investigated. dissected midgut contents were examined using quantitative aerobic bacterial cultures. individual colonies (n = 134) were subcultured and identified to species. midgut bacterial counts changed dramatically during mosquito development. a 280-1,100-fold decrease in the bacterial population occurred between the larval stage and pupal emergence, whereas a subsequent 70-16 ...19968619452
relative abundance and species composition of mosquito populations (diptera:culicidae) in a la crosse virus-endemic area in western north carolina.container surveys were conducted in 5 communities on the cherokee indian reservation, an area of western north carolina endemic for transmission of la crosse (lac) virus, to determine the potential for peridomestic mosquito breeding, the relative abundance of mosquito species, and the standing crop of mosquitoes per residence. eleven species of mosquitoes were collected, but 80.9% of all mosquitoes reared from containers were aedes triseriatus (say). all communities averaged > 6 containers per r ...19968699454
attraction of aedes albopictus adults in sod infusion.aedes albopictus adults were recovered from sod-baited gravid traps at 7 sites in 5 counties of southern and southwestern illinois in areas ranging from suburban to rural. the attraction of this species to a lure usually associated with members of the culex pipiens complex was investigated under laboratory and field conditions. olfactometer and oviposition preference tests in the laboratory showed that ae. albopictus is attracted to sod infusion and females readily oviposit on substrates in cont ...19968723268
replication and expression of a recombinant sindbis virus in mosquitoes.a recombinant sindbis virus, te/3'2j/anti-s, containing lacrosse virus small segment cdna in antisense orientation, was inoculated into aedes triseriatus mosquitoes. virus replication and lac-anti-s rna expression were analysed temporally and spatially. te/3'2j/anti-s virus titre peaked at 5.0 log10 tcid50 in heads 6-9 days post infection (p.i.) and decreased to 3.4 log10 tcid50 by 37 days p.i. salivary glands contained 4.4 log10 tcid50 of virus 6 days p.i.; titres were lower in other organs. la ...19958825762
seasonal occurrence and abundance of aedes triseriatus and other mosquitoes in a la crosse virus-endemic area in western north carolina.the species composition and population abundance of mosquitoes were investigated from may to november in 1989 and 1990 on the cherokee indian reservation, an area of western north carolina endemic for transmission of la crosse (lac) virus. mosquitoes representing 6 genera and 13 species were collected. aedes triseriatus was the most abundant species collected, comprising over 98% of mosquitoes collected by ovitrapping and co2-baited suction trapping, and 88% of resting adults collected by vacuum ...19968827591
effects of la crosse virus infection on pregnant domestic rabbits and mongolian gerbils.the transplacental transmission of la crosse virus (lacv) was evaluated in domestic rabbits (oryctolagus cuniculus) and mongolian gerbils (meriones unguiculatis) as a potential mechanism for the maintenance of the virus. rabbits were infected with lacv at different times of gestation by injection of viral suspensions or by exposure to lacv transovarially (to) infected aedes triseriatus. pregnant gerbils were exposed between 16-24 days of gestation to lacv to- infected ae. triseriatus. our result ...19968916793
la crosse viremias in mongolian gerbils (meriones unguiculatis).we examined the usefulness of mongolian gerbils (meriones unguiculatus) as a new animal model for la crosse virus (lacv) studies. gerbils were exposed to lacv by either intramuscular (im) inoculation or exposure to transovarially infected aedes triseriatus. our studies indicate that gerbils may be a suitable animal model for lacv infection. gerbils were susceptible to lacv, survived viral infection, and developed viremias and neutralizing antibody titers following exposure by im injection and by ...19968940992
analysis of la crosse virus s-segment rna and its positive-sense transcripts in persistently infected mosquito tissues.la crosse (lac) virus is an important cause of pediatric arboviral encephalitis in the united states. lac virus is biologically transmitted by the mosquito aedes triseriatus, and, like other arthropod-borne viruses, it establishes a persistent, nonpathogenic infection in its vector following oral infection. to investigate lac virus persistent infection of mosquitoes, a reverse transcription-pcr assay was developed for the amplification of lac virus negative-sense small (s) genome rna segment, it ...19968971026
parasites of the asian tiger mosquito and other container-inhabiting mosquitoes (diptera:culicidae) in northcentral florida.seven microorganisms including 4 protozoans, 2 fungi, and a bacterium infected aedes albopictus (skuse) larvae collected from 12 counties in northecentral florida. ae albopictus and 14 other species of mosquitoes were collected from tires, flower-holding vases in cemeteries, other types of artificial containers, and treeholes. ascogregarina taiwanensis (lien & levine) was the most common parasite of ae. albopictus throughout the year. the microsporidium vavraia culicis (weiser) infected aedes ae ...19979103767
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