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Beulah M. Parker - One of the best experts on this subject based on the ideXlab platform.
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Density and distribution of Dirofilaria immitis (Nematoda: Filarioidea) third-stage larvae in Aedes sollicitans and Aedes taeniorhynchus (Diptera: Culicidae).
Journal of medical entomology, 2000Co-Authors: Beulah M. ParkerAbstract:Numbers and the distribution of third-stage larvae (L3) were investigated in Aedes sollicitans (Walker) and Aedes taeniorhynchus (Wiedemann) female mosquitoes fed Dirofilaria immitis (Leidy) infectious-blood with densities of microfilariae (mf) ranging from ≈7,100–43,400 mf/ml. At each microfilarial density, a maximum of 63–66 infective larvae were recovered from an Ae. sollicitans alive on day 15 after infection. In comparison with Ae. taeniorhynchus, Ae. sollicitans averaged greater numbers of L3 and from 1.4 to 2.4 times more L3 in the head and labium per infected female. The trend was for greater numbers of L3 to be found in the labium than in the head of Ae. sollicitans, but there were no significant differences between numbers of L3 recovered from these sites in differentially infected females. However, numbers of L3 recovered from the head versus the labium of differentially infected Ae. taeniorhynchus varied significantly with the infectious blood microfilarial density. At the two lowest and highest microfilarial densities, greater numbers of L3 were recovered from the head and labium, respectively. Variations among species in the female body size, blood meal size, and retention of L3 may be factors responsible for differences observed between the total numbers and percentage distribution of D. immitis L3 recovered from the simultaneous blood-fed Ae. sollicitans and Ae. taeniorhynchus.
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variation in mosquito diptera culicidae relative abundance and dirofilaria immitis nematoda filarioidea vector potential in coastal north carolina
Journal of Medical Entomology, 1993Co-Authors: Beulah M. ParkerAbstract:At an enzootic focus of Dirofilaria immitis in coastal North Carolina, mosquito populations were sampled June–September 1985 and on several occasions during August–October 1986 and June–August 1987, to identify local vectors and to determine relative abundance and D. immitis infection rates. Predominant species collected were Anopheles bradleyi King (66.6%), Culex salinarius Coquillett (15.9%), Aedes taeniorhynchus (Wiedemann) (8.2%), and Aedes sollicitans (Walker) (4.9%). Population abundance varied within and among seasons. D. immitis infection was found in An. bradleyi (1.2%), Ae. taeniorhynchus (0.9%), and Ae. sollicitans (0.9%). Of infected An. bradleyi, 88% were collected June–2 July, whereas the highest number of infected Ae. taeniorhynchus and Ae. sollicitans were found during mid-July 1985. Ae. sollicitans and Ae. taeniorhynchus were the only infected species found during 1986 and 1987. However, based on overall relative abundance and infective rate, An. bradleyi appeared to be the primary vector of D. immitis in the study area.
Lena B Brattsten - One of the best experts on this subject based on the ideXlab platform.
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identification and analysis of nadph cytochrome p450 reductase in Aedes sollicitans diptera culicidae
Journal of Medical Entomology, 2014Co-Authors: Chansak Suwanchaichinda, D Sun, Lena B BrattstenAbstract:An NADPH-cytochrome P450 reductase (CPR) gene was identified in Aedes sollicitans Walker (Diptera: Culicidae). The open reading frame is 2,040 bp long, encoding a 679-residue polypeptide. Amino acid sequence analysis indicates that the Ae. sollicitans CPR carries conserved ligand-binding domains and belongs to the same phylogenetic group as CPRs in other mosquitoes. The cDNA of the CPR gene was cloned, and the recombinant protein was expressed in Escherichia coli. Cytochrome c reductase activity was detected in the bacterial cytosolic and membrane fractions and in larval microsomes from two New Jersey Ae. sollicitans populations, indicating that the Ae. sollicitans CPR is enzymatically functional and closely related to that in other dipterans.
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novel cytochrome p450s cyp6bb1 and cyp6p10 from the salt marsh mosquito Aedes sollicitans walker diptera culicidae
Archives of Insect Biochemistry and Physiology, 2008Co-Authors: Shaoming Huang, Debin Sun, Lena B BrattstenAbstract:Based on the conserved heme-binding region and the charge pair consensus of insect cytochrome P450s, two novel full-length P450 cDNAs, CYP6BB1 and CYP6P10, were cloned from the salt marsh mosquito Aedes sollicitans (Walker). CYP6BB1 and CYP6P10 had open reading frames of 1,518 and 1,521 nucleotides encoding 506 and 507 amino acid residue proteins, respectively. Several alleles with amino acid substitutions were found both in CYP6BB1 and CYP6P10. The deduced proteins are typical microsomal P450s sharing signature sequences with other insect CYP6 P450s. Sequence analysis showed that both CYP6BB1 and CYP6P10 shared highest sequence identities with P450 CYP6P4, 56% and 65%, respectively. Phylogenetic analysis showed both CYP6BB1 and CYP6P10 were grouped into the clade containing several P450s from subfamily CYP6P. Real-time RT-PCR analysis showed CYP6BB1 but not CYP6P10 transcription in females was significantly increased 24 h after a blood meal. Neither CYP6BB1 nor CYP6P10 were life stage or gender specific. Protein expression experiments are needed to determine the functions of these proteins. Arch. Insect Biochem. Physiol. 2007. © 2007 Wiley-Liss, Inc.
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effect of salinity on temephos toxicity to larvae of Aedes sollicitans diptera culicidae
Journal of Medical Entomology, 2007Co-Authors: Shaoming Huang, Lena B BrattstenAbstract:Aedes sollicitans (Walker) (Diptera: Culicidae) is an important vector of eastern equine encephalitis as well as several other mosquito-borne brain fevers. The larvae are salt-tolerant and develop in salt marshes with highly varying salinity. The effect of salinity on the toxicity of one of the major larvicidal organophosphates, temephos, was evaluated in two groups of larvae raised either in freshwater or water with salinity ranging from 1 to 3.5%. When larvae were raised in freshwater, low salinity (1-3.5%) decreased the toxicity and high salinity (5%) increased the toxicity. In contrast, salinity did not change the toxicity to larvae raised in saltwater. Temephos treatment and salinity seemed to have cross-interaction for the larvae raised in freshwater. High salinity also caused reduction in larval body size, and 5% salinity alone caused mortality for larvae raised in freshwater, suggesting that preadaptation to saltwater in the early instars is essential for survival in later instars at high salinity.
Michael J Turell - One of the best experts on this subject based on the ideXlab platform.
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vector competence of north american mosquitoes diptera culicidae for west nile virus
Journal of Medical Entomology, 2001Co-Authors: Michael J Turell, Monica L Oguinn, David J Dohm, James W JonesAbstract:We evaluated the potential for several North American mosquito species to transmit the newly introduced West Nile (WN) virus. Mosquitoes collected in the New York City metropolitan area during the recent WN virus outbreak, at the Assateague Island Wildlife Refuge, VA, or from established colonies were allowed to feed on chickens infected with WN virus isolated from a crow that died during the 1999 outbreak. These mosquitoes were tested ≈2 wk later to determine infection, dissemination, and transmission rates. Aedes albopictus (Skuse), Aedes atropalpus (Coquillett), and Aedes japonicus (Theobald) were highly susceptible to infection, and nearly all individuals with a disseminated infection transmitted virus by bite. Culex pipiens L. and Aedes sollicitans (Walker) were moderately susceptible. In contrast, Aedes vexans (Meigen), Aedes aegypti (L.), and Aedes taeniorhynchus (Wiedemann) were relatively refractory to infection, but individual mosquitoes inoculated with WN virus did transmit virus by bite. Infected female Cx. pipiens transmitted WN virus to one of 1,618 F1 progeny, indicating the potential for vertical transmission of this virus. In addition to laboratory vector competence, host-feeding preferences, relative abundance, and season of activity also determine the role that these species could play in transmitting WN virus.
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transmission of venezuelan equine encephalomyelitis virus by Aedes sollicitans and Aedes taeniorhynchus diptera culicidae
Journal of Medical Entomology, 1992Co-Authors: Michael J Turell, George V Ludwig, Joseph R BeamanAbstract:Experimental studies compared the vector competence of Aedes sollicitans (Skuse) and Ae. taeniorhynchus (Wiedemann) collected on Assateague Island, Va., for an epizootic strain (Trinidad donkey) of Venezuelan equine encephalomyelitis (VEE) virus. Infection rates were significantly higher in Ae. sollicitans (101/107, 94%) than in Ae. taeniorhynchus (103/175, 59%), even though both species fed concurrently on the same infected hamsters. Similarly, dissemination and transmission rates were significantly higher in the Ae. sollicitans population tested. Although both Ae. taeniorhynchus and Ae. sollicitans are natural vectors of VEE virus, the latter species should be considered a more efficient vector of VEE epizootic strains, based on its greater susceptibility to infection and higher transmission rates.
Robert B. Tesh - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Port Bolivar Virus, a Novel Entomobirnavirus (Birnaviridae) Isolated from Mosquitoes Collected in East Texas, USA.
Viruses, 2020Co-Authors: Robert B. Tesh, Bethany G. Bolling, Hilda Guzman, Vsevolod L. Popov, Ashley Wilson, Steven G. Widen, Thomas G. Wood, Peter J. Walker, Nikos VasilakisAbstract:This report describes and characterizes a novel entomobirnavirus, designated Port Bolivar virus (PTBV), that was isolated from a pool of Aedes sollicitans mosquitoes collected in a saltwater marsh in East Texas, USA. Full genome sequencing and phylogenetic analyses indicate that PTBV is distinct but genetically related to Drosophila X virus and mosquito X virus, which are assigned to species in the genus Entomobirnavirus, family Birnaviridae. PTBV produced cytopathic effect (CPE) in cultures of mosquito (C6/36) cells, but not in Vero cell cultures. Ultrastructural studies of PTBV in infected C6/36 cells demonstrated unenveloped virus particles about 55 nm in diameter.
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variation in interferon sensitivity and induction among strains of eastern equine encephalitis virus
Journal of Virology, 2005Co-Authors: Patricia V Aguilar, Douglas M Watts, Slobodan Paessler, Annesophie Carrara, Samuel Baron, Joyce Poast, Eryu Wang, Abelardo C Moncayo, Michael Anishchenko, Robert B. TeshAbstract:Eastern equine encephalitis virus (EEEV) is an arthropod-borne virus (arbovirus) in the family Togaviridae, genus Alphavirus. The virus possesses a single-stranded, messenger-sense RNA genome of ca. 11.7 kb that encodes four nonstructural proteins (nsP1 to -4) and three main structural proteins (capsid and glycoproteins E1 and E2) (47). The virus is an important veterinary and human pathogen and causes periodic outbreaks in the Americas associated with high morbidity and mortality among humans and equines. In humans, EEEV infection is characterized mainly by fever, lethargy, vomiting, convulsions, and coma. Surviving patients, especially children, are often profoundly affected by neurological and physical sequelae that include mental retardation, hemiparesis, aphasia, emotional instability, convulsions, hemiplegia, strabismus, impaired vision, partial deafness, and speech disorders (45). In equines, pheasants, chickens, sandhill cranes, emus, and pigs, EEEV infection also causes severe and often fatal disease (54). EEEV was first isolated in the United States from horses during an epizootic in coastal regions of Virginia, Maryland, and Delaware in 1933 (5, 48) and in South America (SA) in 1930 from a horse in Argentina (40). In North America (NA), the enzootic transmission cycle occurs in freshwater swamp foci and involves passerine birds and the ornithophilic mosquito vector, Culiseta melanura. Sporadic epizootic or epidemic transmission involves spillover from the avian swamp cycle and is probably mediated by bridge vectors such as Aedes canadensis, Aedes sollicitans, Aedes vexans, and Coquillettidia perturbans (24, 35, 54). Enzootic transmission in Central and SA is not well understood but probably involves mosquitoes in the Culex (Melanoconion) subgenus and rodent and/or avian reservoir hosts (44, 54). Antigenic studies have shown that NA strains of EEEV differ from those found in SA and that these two geographic variants also differ in biological and epidemiological characteristics (12-14, 38). Genetic and antigenic studies (9, 38, 55) revealed that NA strains are highly conserved, constituting a unique major lineage, whereas SA strains constitute three major lineages with more antigenic and genetic variation. All strains isolated in NA and most from the Caribbean belong to the NA subtype (lineage I), whereas isolates from Central and SA constitute three SA subtypes (lineages II to IV) (9, 11, 14). Importantly, the NA subtype causes severe disease in both humans and equines, with mortality rates of 30 to 80% in humans and 90 to 95% in equines. In contrast, infection by the SA EEEV subtypes can be fatal in equines, but human infections have rarely been recognized and in most cases were identified only by serosurveys with no evidence of disease. Causey and Theiler (16) demonstrated seroprevalence as high as 25% in children and 31% in adults living in the Amazon basin, and a single human encephalitis case was also reported in Brazil (1). Although EEEV was implicated in equine epizootics in Braganca, Para State, no neurological disease in humans was reported during these outbreaks (15, 50, 53). The EEEV was also isolated repeatedly in Argentina from horses between 1930 and 1958. However, no human neurological disease was reported despite active surveillance and human seroprevalence levels of up to 66% in some locations (42). Recently, EEEV was isolated from Culex (Melanoconion) pedroi mosquitoes in Puerto Almendras, Iquitos, Peru (M. Turell, USAMRIID [unpublished data]), providing evidence that EEEV circulates throughout the Amazon basin. However, again, no fatal or neurologic human disease associated with EEEV has been recognized in Peru despite active surveillance there for febrile diseases. These epidemiological studies provide strong evidence that, unlike their NA counterparts, SA strains of EEEV generally do not produce severe disease but can infect humans. The reason for this apparent difference in human virulence is unknown. Interferons (IFNs) have long been recognized as essential components of the innate immune response to viral infections (3, 4, 30). Specifically, IFN-α and -β are known to be important in protecting against alphaviral disease (26, 46). Previous studies showed a correlation between alphavirus virulence and resistance to IFN-α and -β. Some studies with Venezuelan equine encephalitis virus (VEEV) suggested that the IFN-α and -β resistance or sensitivity phenotype correlated with epizootic potential and equine virulence (31, 46), although others observed little or no difference (2). Although an important role of IFN-α/β in the pathogenesis of several alphaviruses, including Sindbis virus (SINV) and Semliki Forest virus (29, 36, 41), has been described, little information is available regarding the role of IFN-α, -β, and especially of IFN-γ in the pathogenesis of other alphaviruses, including EEEV. We therefore hypothesized that NA strains of EEEV are more virulent for humans because of a greater resistance to IFN than SA strains and/or because they induce lower levels of IFN. To test these hypotheses, the effects of IFN on EEEV replication were evaluated in Vero cells treated with human IFN-α/β and -γ. Vero cells were chosen because they respond efficiently to human IFN but are unable to produce IFN, eliminating any possibility of autocrine or paracrine effects. For the in vivo studies, the mouse model was used because it allowed us to study the effect of ablating the IFN response on EEEV infection and disease outcome.
Shirley J Tirrellpeck - One of the best experts on this subject based on the ideXlab platform.
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multiple isolations of eastern equine encephalitis and highlands j viruses from mosquitoes diptera culicidae during a 1996 epizootic in southeastern connecticut
Journal of Medical Entomology, 1998Co-Authors: Theodore G Andreadis, John F Anderson, Shirley J TirrellpeckAbstract:Thirty-six isolations of eastern equine encephalitis virus were obtained from 8 species of mosquitoes collected from 5 September through 18 October 1996 during an epizootic in southeastern Connecticut. These included Culiseta melanura (Coquillett) (19 isolates), Culex pipiens L. (8), Culiseta morsitans (Theobald) (3), Aedes sollicitans (Walker) (2), Aedes cantator (Coquillett) (1), Aedes trivittatus (Coquillett) (1), Aedes vexans (Meigen) (1), and Coquillettidia perturbans (Walker) (1). Isolations from Ae. cantator and Ae. trivittaus are new to North American records, and those from Ae. cantator and Ae. sollicitans represent the first infections of human-biting, salt-marsh mosquitoes with eastern equine encephalitis virus in Connecticut. With one exception, eastern equine encephalitis-infected Cs. melanura were found at all sites where eastern equine encephalitis virus was isolated. The large number of eastern equine encephalitis isolations from Cs. melanura and the collection of infected mosquitoes in residential woodlots and coastal salt marshes away from traditional red maple or white cedar swamp habitats, reaffirm the importance of local populations of this mosquito for viral amplification and dispersal from swamp foci. Highlands J virus was more widespread geographically, but fewer isolations of this vims were made from fewer species of mosquitoes. These included Cs. melanura (8 isolates), Cx. pipiens (5), Ae. vexans (3), Aedes canadensis (Theobald) (1), Ae. cantator (1) and Cs. morsitans (1). No human or horse cases of eastern equine encephalitis were reported, although this represents the largest number of isolations for eastern equine encephalitis ever recovered from field-collected mosquitoes in Connecticut.