Real-Time Reverse Transcriptase–polymerase Chain Reaction Quantification of West Nile Virus Transmitted by Culex Pipiens Quinquefasciatus

Vanlandingham, Dana L.; Schneider, Bradley S.; Klingler, Kimberly A.; Fair, Joseph N.; Beasley, David W.C.; Huang, Jing; Hamilton, Patricia; Higgs, Stephen

doi:10.4269/ajtmh.2004.71.120

Cited by 85 publications

(71 citation statements)

References 20 publications

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“…Depending on the virus, mosquito species, and method of quantification employed, the estimated level of virus inoculated within mosquito saliva ranges from approximately 10 1 to 10 7 pfu (Colton et al 2005, Colton and Nasci 2006, Gubler and Rosen 1976, Reisen et al 2005, Smith et al 2005, Styer et al 2007, Vanlandingham et al 2004). As described above, components of mosquito saliva have immunomodulatory activity, and thus, as a consequence, mosquito saliva can affect the anti-viral immune response and virus pathogenesis.…”

Section: Mosquito Associated Potentiation Of Arbovirus Transmission Amentioning

confidence: 99%

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

Schneider

Higgs

2008

Transactions of the Royal Society of Tropical Medicine and Hygi

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SUMMARYArthropod-borne viruses have emerged as a major human health concern. Viruses transmitted by mosquitoes are the cause of the most serious and widespread arbovirus diseases worldwide and are ubiquitous in both feral and urban settings. Arboviruses, including dengue and West Nile virus are injected into vertebrates within mosquito saliva during mosquito feeding. Mosquito saliva contains anti-haemostatic, anti-inflammatory and immunomodulatory molecules that facilitate the acquisition of a blood-meal. Collectively, studies investigating the effects of mosquito saliva on the vertebrate immune response suggest that at high concentrations salivary proteins are immmunosuppressive, whereas lower concentrations modulate the immune response; specifically, T H 1 and antiviral cytokines are down-regulated, while T H 2 cytokines are unaffected or amplified. As a consequence, mosquito saliva can impair the anti-viral immune response thus affecting viral infectiousness and host survival. Mounting evidence suggests that this is a mechanism whereby arbovirus pathogenicity is enhanced. In a range of disease models, including various hosts, mosquito species, and arthropodborne viruses, mosquito saliva and/or feeding is associated with a potentiation of virus infection. Compared to arbovirus infection initiated in absence of the mosquito or its saliva, infection including mosquito saliva leads to an increase in virus transmission, host susceptibility, viraemia, disease progression, and mortality.Keywords arthropod-borne virus; mosquito saliva; immunomodulation; disease enhancement Most arthropod-borne (arbo)viruses of public health significance are mosquito-borne, and thus transmitted to vertebrates via the feeding of an infected mosquito. For a mosquito to

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Section: Mosquito Associated Potentiation Of Arbovirus Transmission Amentioning

confidence: 99%

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

Schneider

Higgs

2008

Transactions of the Royal Society of Tropical Medicine and Hygi

Self Cite

225

198

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“…Virus was diluted in BA-1 and titer verified by plaque assay on Vero cells at the time of inoculation. This dose was deemed to be within the range of documented viral load in mosquito saliva and was the approximate equivalent infectious dose delivered by 1 to 6 mosquito bites (10 1.3 -10 3.8 PFU equivalents; Bunning et al, 2002;Vanlandingham et al, 2004). During the postinfection period, blood from grouse was collected daily to quantify viremia (up to the point of death, or the end-point of the experiment, i.e., 14 days).…”

Section: Experimental Infectionmentioning

confidence: 99%

Susceptibility of Greater Sage-Grouse to Experimental Infection With West Nile Virus

Clark

Hall

McLean

et al. 2006

Journal of Wildlife Diseases

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ABSTRACT:Populations of greater sage-grouse (Centrocercus urophasianus) have declined 45-80% in North America since 1950. Although much of this decline has been attributed to habitat loss, recent field studies have indicated that West Nile virus (WNV) has had a significant negative impact on local populations of grouse. We confirm the susceptibility of greater sage-grouse to WNV infection in laboratory experimental studies. Grouse were challenged by subcutaneous injection of WNV (10 3.2 plaque-forming units [PFUs]). All grouse died within 6 days of infection. The Kaplan-Meier estimate for 50% survival was 4.5 days. Mean peak viremia for nonvaccinated birds was 10 6.4 PFUs/ml (610 0.2 PFUs/ml, standard error of the mean [SEM]). Virus was shed cloacally and orally. Four of the five vaccinated grouse died, but survival time was increased (50% survival59.5 days), with 1 grouse surviving to the end-point of the experiment (14 days) with no signs of illness. Mean peak viremia for the vaccinated birds was 10 2.3 PFUs/ml (610 0.6 PFUs/ml, SEM). Two birds cleared the virus from their blood before death or euthanasia. These data emphasize the high susceptibility of greater sage-grouse to infection with WNV.

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“…This WNV isolate (16399-3) was originally collected from an American Crow in New York during the 1999 outbreak, passed twice through Vero cell culture, and stored frozen at 280 C. The dose (10 5 PFU) was at the upper range of virus concentration reported for saliva of WNVinfected Cx. quinquefasciatus (Vanlandingham et al, 2004) but less than the mean dose of 10 5.9 PFU reported for Culex pipiens probing on a live host (Styer et al, 2007).…”

Section: Experimental Infections Of`amakihi and House Sparrowsmentioning

confidence: 73%

Experimental Infection of Hawai`i `Amakihi (Hemignathus Virens) With West Nile Virus and Competence of a Co-Occurring Vector, Culex Quinquefasciatus: Potential Impacts on Endemic Hawaiian Avifauna

LaPointe

Hofmeister

Atkinson

et al. 2009

Journal of Wildlife Diseases

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ABSTRACT:Introduced mosquito-borne avian disease is a major limiting factor in the recovery and restoration of native Hawaiian forest birds. Annual epizootics of avian pox (Avipoxvirus) and avian malaria (Plasmodium relictum) likely led to the extinction of some species and continue to impact populations of susceptible Hawaiian honeycreepers (Drepanidinae). The introduction of a novel pathogen, such as West Nile virus (WNV), could result in further population declines and extinctions. During September and October 2004, we infected Hawai`i`Amakihi (Hemignathus virens) with a North American isolate of WNV by needle inoculation and mosquito bite to observe susceptibility, mortality, and illness in this endemic passerine, and to determine the vector competence of the co-occurring, introduced mosquito Culex quinquefasciatus. All experimentally infected Hawai`i`Amakihi became viremic, with a mean titer .10 5 plaque-forming units (PFU)/ ml, and they experienced clinical signs ranging from anorexia and lethargy to ataxia. The fatality rate among needle-inoculated Hawai`i`Amakihi (n516) was 31.3%, but mortality in free-ranging birds is likely to increase due to predation, starvation, thermal stress, and concomitant infections of avian malaria and pox. Surviving Hawai`i`Amakihi seem to clear WNV from the peripheral blood by 7-10 days postinfection (DPI), and neutralizing antibodies were detected from 9 to 46 DPI. In transmission trials, Hawaiian Cx. quinquefasciatus proved to be a competent vector and Hawai`ì Amakihi an adequate amplification host of WNV, suggesting that epizootic WNV could readily become an additional limiting factor of some native Hawaiian bird populations.

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Real-Time Reverse Transcriptase–polymerase Chain Reaction Quantification of West Nile Virus Transmitted by Culex Pipiens Quinquefasciatus

Cited by 85 publications

References 20 publications

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

The enhancement of arbovirus transmission and disease by mosquito saliva is associated with modulation of the host immune response

Susceptibility of Greater Sage-Grouse to Experimental Infection With West Nile Virus

Experimental Infection of Hawai`i `Amakihi (Hemignathus Virens) With West Nile Virus and Competence of a Co-Occurring Vector, Culex Quinquefasciatus: Potential Impacts on Endemic Hawaiian Avifauna

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