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William K. Reisen - One of the best experts on this subject based on the ideXlab platform.

  • Blood meal exposure of Culex tarsalis females and resulting infection rates.
    2019
    Co-Authors: Gabriella Worwa, Andra A. Hutton, Aaron C. Brault, William K. Reisen
    Abstract:

    Blood meal exposure of Culex tarsalis females and resulting infection rates.

  • Viral titer and RNA copy numbers from Culex tarsalis blood meals and relative input ratios between groups.
    2015
    Co-Authors: Gabriella Worwa, Sarah S Wheeler, Aaron C. Brault, William K. Reisen
    Abstract:

    a Mean value and standard deviation of five fully engorged females frozen immediately after blood meal uptake.b Relative input RNA ratio between competing wildtype virus and COAV997-5nt calculated from mixed infection groups.c Relative input RNA ratio between wildtype virus and COAV997-5nt calculated from singly infected groups. Each ratio accounts for differences between the inoculum of either COAV997-IC NY99-IC or CA-04 groups compared to the COAV997-5nt group.Experimental groups and the total number (n) of living females collected on day 14 are presented on the left. Viral titers of the infectious blood meal and of five fully engorged females collected right after blood meal exposure of each group were analyzed by plaque assay titration and are shown as log10 PFU/mL with standard deviation. The relative input (inoculum) ratio between the mean RNA copies from wildtype viruses and COAV997-5nt in the five mosquitoes was calculated for each mixed competition group by dividing the wildtype RNA copies by COAV997-5nt RNA copies followed by standard deviation. The same ratio was calculated for wildtype singly infected mosquitoes in reference to the COAV997-5nt singly inoculated mosquitoes.Viral titer and RNA copy numbers from Culex tarsalis blood meals and relative input ratios between groups.

  • Comparative study of the pathological effects of western equine encephalomyelitis virus in four strains of Culex tarsalis Coquillett (Diptera: Culicidae)
    Frontiers Media S.A., 2014
    Co-Authors: William K. Reisen, Marco Eneira, Farida Emahmood, Calvin B. L. James, William S. Romoser
    Abstract:

    Early reports suggested that mosquito cells infected with arboviruses remain viable and undamaged. However, more recent experimental evidence suggests that arboviral infection of mosquito tissues might indeed result in pathological changes, with potential implications for vector survival and virus transmission. Here, we compare the pathological effects of western equine encephalomyelitis virus (WEEV) infection in four strains of Culex tarsalis previously reported to differ in their competence as WEEV vectors. Pathological effects were observed in cells of the midgut epithelium, salivary glands and eggs. Cell rounding and sloughing of midgut epithelial cells was associated with those strains reported to be the least susceptible to WEEV infection, whereas midgut necrosis and vacuolation upon infection were associated with strains showing higher susceptibility. Although pathological effects were sporadically observed in infected salivary glands, further studies are required to evaluate their impact on vector competence. Additionally, the potential implications of observed Cx. tarsalis egg infection with WEEV are discussed

  • Spatial Variation in Host Feeding Patterns of Culex tarsalis and the Culex pipiens Complex (Diptera: Culicidae) in California
    Journal of Medical Entomology, 2012
    Co-Authors: Tara Thiemann, D. A. Lemenager, Hugh D. Lothrop, Brian D. Carroll, Susanne Kluh, William K. Reisen
    Abstract:

    West Nile virus (family Flaviviridae, genus Flavivirus, WNV) is now endemic in California across a variety of ecological regions that support a wide diversity of potential avian and mammalian host species. Because different avian hosts have varying competence for WNV, determining the blood-feeding patterns of Culex (Diptera: Culicidae) vectors is a key component in understanding the maintenance and amplification of the virus as well as tangential transmission to humans and horses. We investigated the blood-feeding patterns of Culex tarsalis Coquillett and members of the Culex pipiens L. complex from southern to northern California. Nearly 100 different host species were identified from 1,487 bloodmeals, by using the mitochondrial gene cytochrome c oxidase I (COI). Cx. tarsalis fed on a higher diversity of hosts and more frequently on nonhuman mammals than did the Cx. pipiens complex. Several WNV-competent host species, including house finch and house sparrow, were common bloodmeal sources for both vector species across several biomes and could account for WNV maintenance and amplification in these areas. Highly competent American crow, western scrub-jay and yellow-billed magpie also were fed upon often when available and are likely important as amplifying hosts for WNV in some areas. Neither species fed frequently on humans (Cx. pipiens complex [0.4%], Cx. tarsalis [0.2%]), but with high abundance, both species could serve as both enzootic and bridge vectors for WNV.

  • The Contrasting Bionomics of Culex Mosquitoes in Western North America
    Journal of the American Mosquito Control Association, 2012
    Co-Authors: William K. Reisen
    Abstract:

    Mosquitoes in the genus Culex are the primary enzootic maintenance and bridge vectors of the North American encephalitides, now including West Nile virus. This review briefly summarizes the biology of three key vector species in western North America, Culex tarsalis, Cx. pipiens complex and Cx. stigmatosoma, focusing on the long history of research done in California. Topics reviewed include population genetic structure, larval ecology, autogeny, mating behavior, host-seeking behavior, host-selection patterns, and overwintering strategies. These attributes collectively have allowed the successful exploitation of anthropogenically altered ecosystems and enabled the role of these species as maintenance and bridge vectors of arboviruses.

Jason L. Rasgon - One of the best experts on this subject based on the ideXlab platform.

  • Vector competence of selected North American Anopheles and Culex mosquitoes for Zika virus
    PeerJ Inc., 2018
    Co-Authors: Brittany L Dodson, Sujit Pujhari, Jason L. Rasgon
    Abstract:

    Zika virus (ZIKV) is a vector-borne flavivirus that has caused recent outbreaks associated with serious disease in infants and newborns in the Americas. Aedes mosquitoes are the primary vectors for ZIKV, but little is known about the diversity of mosquitoes that can transmit ZIKV in North America. We chose three abundant North American mosquito species (Anopheles freeborni, Anopheles quadrimaculatus, and Culex tarsalis) and one known vector species (Aedes aegypti), fed them blood meals supplemented with a recent outbreak ZIKV strain, and tested bodies, legs, and saliva for infectious ZIKV. ZIKV was able to infect, disseminate, and be transmitted by Aedes aegypti. However, Anopheles freeborni, Anopheles quadrimaculatus, and Culex tarsalis were unable to be infected. We conclude that these species are unlikely to be involved in ZIKV transmission in North America. However, we should continue to examine the ability for other mosquito species to potentially act as ZIKV vectors in North America

  • Wolbachia effects on Rift Valley fever virus infection in Culex tarsalis mosquitoes.
    Public Library of Science (PLoS), 2017
    Co-Authors: Brittany L Dodson, Elizabeth S Andrews, Michael J Turell, Jason L. Rasgon
    Abstract:

    Innovative tools are needed to alleviate the burden of mosquito-borne diseases, and strategies that target the pathogen are being considered. A possible tactic is the use of Wolbachia, a maternally inherited, endosymbiotic bacterium that can (but does not always) suppress diverse pathogens when introduced to naive mosquito species. We investigated effects of somatic Wolbachia (strain wAlbB) infection on Rift Valley fever virus (RVFV) in Culex tarsalis mosquitoes. When compared to Wolbachia-uninfected mosquitoes, there was no significant effect of Wolbachia infection on RVFV infection, dissemination, or transmission frequencies, nor on viral body or saliva titers. Within Wolbachia-infected mosquitoes, there was a modest negative correlation between RVFV body titers and Wolbachia density, suggesting that Wolbachia may slightly suppress RVFV in a density-dependent manner in this mosquito species. These results are contrary to previous work in the same mosquito species, showing Wolbachia-induced enhancement of West Nile virus infection rates. Taken together, these results highlight the importance of exploring the breadth of pathogen modulations induced by Wolbachia

  • Culex tarsalis Vitellogenin Gene Promoters Investigated In Silico and In Vivo Using Transgenic Drosophila melanogaster
    2016
    Co-Authors: Song Chen, Jason L. Rasgon
    Abstract:

    Introduction: Genetic modification, or transgenesis, is a powerful technique to investigate the molecular interactions between vector-borne pathogens and their arthropod hosts, as well as a potential novel approach for vector-borne disease control. Transgenesis requires the use of specific regulatory regions, or promoters, to drive expression of genes of interest in desired target tissues. In mosquitoes, the vast majority of described promoters are from Anopheles and Aedes mosquitoes. Results: Culex tarsalis is one of the most important vectors of arboviruses (including West Nile virus) in North America, yet i

  • Wolbachia Enhances West Nile Virus (WNV) Infection in the Mosquito Culex tarsalis
    2016
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector

  • wolbachia enhances west nile virus wnv infection in the mosquito Culex tarsalis
    PLOS Neglected Tropical Diseases, 2014
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

James L Hardy - One of the best experts on this subject based on the ideXlab platform.

  • seasonal variation in the vector competence of Culex tarsalis diptera culicidae from the coachella valley of california for western equine encephalomyelitis and st louis encephalitis viruses
    Journal of Medical Entomology, 1996
    Co-Authors: William K. Reisen, S B Presser, James L Hardy, R E Chiles
    Abstract:

    The vector competence of Culex tarsalis Coquillett from the Coachella Valley of California for western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses was monitored monthly from February to November 1993. The concentration of WEE virus required to infect 50% of the females increased during summer coincidentally with ambient temperature and was highest during July. Transmission rates of WEE virus were high during March, low during May-June, and high again during July-September. Females expressed both mesenteronal escape and salivary gland barriers limiting WEE virus dissemination and transmission rates, respectively. SLE virus infection and dissemination rates did not vary among months, but transmission rates, were highest during July-September. Although infection rates with SLE virus were moderate, most infected females developed disseminated infections. Salivary gland infection or escape barriers prevented SLE virus transmission in 16-100% of infected females.

  • bionomics of Culex tarsalis diptera culicidae in relation to arbovirus transmission in southeastern california
    Journal of Medical Entomology, 1995
    Co-Authors: William K. Reisen, H D Lothrop, James L Hardy
    Abstract:

    Population dynamics and bionomics of host-seeking Culex tarsalis Coquillett were studied in the Imperial and Coachella valleys of California during periods in 1991 and 1992 when western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses were transmitted to sentinel chickens. Female abundance was greatest during the spring and fall, before and after most virus transmission occurred and was not correlated with temperature, humidity, or rainfall. Parity rates were highest during late summer when virus activity peaked and were lowest during December when females may enter a short-term reproductive diapause. Although most likely underestimated, the proportion of older multiparous females were collected at a consistent, but low level throughout the year. Changes in the parity rate seemed to be influenced primarily by the proportions of 1-parous females. Survivorship estimated from the parity rate (adjusted to account for autogeny) was highest in winter; however, the proportion of females surviving to potentially transmit either WEE or SLE virus was highest in summer and early fall. Wing length decreased in summer as an inverse correlate of temperature and increased as a function of female age, implying that larger females lived longest. However, autogenous females were larger than anautogenous females at emergence and only parous autogenous females were collected host seeking, thereby confounding the relationship between size and age. The proportion of females testing positive for fructose was greatest during winter and lowest during summer, perhaps affecting survivorship and blood-feeding avidity. The vector competence (infection, dissemination and transmission rates, and ID50) of females collected host seeking or emerging from field-collected pupae for WEE or SLE viruses remained similar over time, even though the wing length of females used in these experiments differed among samples. We conclude that in nature virus transmission progressed efficiently during midsummer because elevated temperatures shortened the extrinsic incubation period without markedly decreasing survivorship resulting in an increased proportion of females surviving extrinsic incubation to become infective.

  • landscape ecology of arboviruses in southern california patterns in the epizootic dissemination of western equine encephalomyelitis and st louis encephalitis viruses in coachella valley 1991 1992
    Journal of Medical Entomology, 1995
    Co-Authors: William K. Reisen, James L Hardy, H D Lothrop
    Abstract:

    Temporal and spatial patterns in the initiation and dissemination of western equine encephalomyelitis and St. Louis encephalitis virus activity in Coachella Valley during 1991 and 1992 were detected by testing pools of host-seeking Culex tarsalis Coquillett for virus infection and sentinel chickens for seroconversions. Both viruses repeatedly were detected first at a salt marsh adjacent to the Salton Sea in the southeastern corner of the study area and then disseminated to the northwest to freshwater marsh, agricultural, and residential habitats. Virus dissemination was relatively slow (< 1 km/d) and may have been accomplished by dispersive host-seeking mosquitoes. Repeated early-season recovery of virus activity indicated that both viruses may persist interseasonally in salt marsh habitat.

  • effect of temperature on the transmission of western equine encephalomyelitis and st louis encephalitis viruses by Culex tarsalis diptera culicidae
    Journal of Medical Entomology, 1993
    Co-Authors: William K. Reisen, R P Meyer, S B Presser, James L Hardy
    Abstract:

    The extrinsic incubation rate (inverse of the time in days from infection to median transmission) of western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses by laboratory strains of Culex tarsalis Coquillett increased as a linear function of incubation temperatures from 10 to 30°C. The estimated temperatures for zero transmission thresholds (intercept of the X axis) were 10.9 and 14.9°C, and the number of degree days above these thresholds required for median transmission (inverse of the slope) was 67.6 and 115.2, respectively. Although the bodies of most Cx. tarsalis females remained infected and the WEE viral titer did not decrease significantly throughout the incubation periods at all temperatures, transmission rates by females incubated at 20 to 30°C decreased markedly after peaking at 7–10 d after infection. In contrast, midgut escape and salivary gland infection barriers limited the transmission rates of SLE virus at all temperatures, but these rates did not decrease markedly as a function of incubation time, indicating that virus modulation did not occur. Degree-day models were used to calculate monthly changes in the duration of the extrinsic incubation period for WEE and SLE viruses in the San Joaquin and Coachella valleys based on mosquito temperatures estimated by combining nocturnal air and diurnal resting site temperatures. Temperatures in the San Joaquin Valley averaged 5°C cooler than in the Coachella Valley, proportionately shortening the duration of the potential transmission season for WEE virus from 10 to 8 mo and for SLE virus from 8 to 5 mo, respectively.

Brittany L Dodson - One of the best experts on this subject based on the ideXlab platform.

  • Vector competence of selected North American Anopheles and Culex mosquitoes for Zika virus
    PeerJ Inc., 2018
    Co-Authors: Brittany L Dodson, Sujit Pujhari, Jason L. Rasgon
    Abstract:

    Zika virus (ZIKV) is a vector-borne flavivirus that has caused recent outbreaks associated with serious disease in infants and newborns in the Americas. Aedes mosquitoes are the primary vectors for ZIKV, but little is known about the diversity of mosquitoes that can transmit ZIKV in North America. We chose three abundant North American mosquito species (Anopheles freeborni, Anopheles quadrimaculatus, and Culex tarsalis) and one known vector species (Aedes aegypti), fed them blood meals supplemented with a recent outbreak ZIKV strain, and tested bodies, legs, and saliva for infectious ZIKV. ZIKV was able to infect, disseminate, and be transmitted by Aedes aegypti. However, Anopheles freeborni, Anopheles quadrimaculatus, and Culex tarsalis were unable to be infected. We conclude that these species are unlikely to be involved in ZIKV transmission in North America. However, we should continue to examine the ability for other mosquito species to potentially act as ZIKV vectors in North America

  • Wolbachia effects on Rift Valley fever virus infection in Culex tarsalis mosquitoes.
    Public Library of Science (PLoS), 2017
    Co-Authors: Brittany L Dodson, Elizabeth S Andrews, Michael J Turell, Jason L. Rasgon
    Abstract:

    Innovative tools are needed to alleviate the burden of mosquito-borne diseases, and strategies that target the pathogen are being considered. A possible tactic is the use of Wolbachia, a maternally inherited, endosymbiotic bacterium that can (but does not always) suppress diverse pathogens when introduced to naive mosquito species. We investigated effects of somatic Wolbachia (strain wAlbB) infection on Rift Valley fever virus (RVFV) in Culex tarsalis mosquitoes. When compared to Wolbachia-uninfected mosquitoes, there was no significant effect of Wolbachia infection on RVFV infection, dissemination, or transmission frequencies, nor on viral body or saliva titers. Within Wolbachia-infected mosquitoes, there was a modest negative correlation between RVFV body titers and Wolbachia density, suggesting that Wolbachia may slightly suppress RVFV in a density-dependent manner in this mosquito species. These results are contrary to previous work in the same mosquito species, showing Wolbachia-induced enhancement of West Nile virus infection rates. Taken together, these results highlight the importance of exploring the breadth of pathogen modulations induced by Wolbachia

  • Wolbachia Enhances West Nile Virus (WNV) Infection in the Mosquito Culex tarsalis
    2016
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector

  • wolbachia enhances west nile virus wnv infection in the mosquito Culex tarsalis
    PLOS Neglected Tropical Diseases, 2014
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

  • wolbachia enhances west nile virus wnv infection in the mosquito Culex tarsalis
    PLOS Neglected Tropical Diseases, 2014
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

Laura D Kramer - One of the best experts on this subject based on the ideXlab platform.

  • Wolbachia Enhances West Nile Virus (WNV) Infection in the Mosquito Culex tarsalis
    2016
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector

  • wolbachia enhances west nile virus wnv infection in the mosquito Culex tarsalis
    PLOS Neglected Tropical Diseases, 2014
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

  • wolbachia enhances west nile virus wnv infection in the mosquito Culex tarsalis
    PLOS Neglected Tropical Diseases, 2014
    Co-Authors: Brittany L Dodson, Grant L Hughes, Oluwatobi Paul, Amy C Matacchiero, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

  • effects of larval rearing temperature on immature development and west nile virus vector competence of Culex tarsalis
    Parasites & Vectors, 2012
    Co-Authors: Brittany L Dodson, Laura D Kramer, Jason L. Rasgon
    Abstract:

    Background: Temperature is known to induce changes in mosquito physiology, development, ecology, and in some species, vector competence for arboviruses. Since colonized mosquitoes are reared under laboratory conditions that can be significantly different from their field counterparts, laboratory vector competence experiments may not accurately reflect natural vector-virus interactions. Methods: We evaluated the effects of larval rearing temperature on immature development parameters and vector competence of two Culex tarsalis strains for West Nile virus (WNV). Results: Rearing temperature had a significant effect on mosquito developmental parameters, including shorter time to pupation and emergence and smaller female body size as temperature increased. However, infection, dissemination, and transmission rates for WNV at 5, 7, and 14 days post infectious feeding were not consistently affected. Conclusions: These results suggest that varying constant larval rearing temperature does not significantly affect laboratory estimates of vector competence for WNV in Culex tarsalis mosquitoes.