Attractiveness of a four-component pheromone blend to male navel orangeworm moths.

The attractiveness to male navel orangeworm moth, Amyelois transitella, of various combinations of a four-component pheromone blend was measured in wind-tunnel bioassays. Upwind flight along the pheromone plume and landing on the odor source required the simultaneous presence of two components, (11Z,13Z)-hexadecadienal and (3Z,6Z,9Z,12Z,15Z)-tricosapentaene, and the addition of either (11Z,13Z)-hexadecadien-1-ol or (11Z,13E)-hexadecadien-1-ol. A mixture of all four components produced the highest levels of rapid source location and source contact.

Temporal changes in distribution, prevalence and intensity of northern fowl mite (Ornithonyssus sylviarum) parasitism in commercial caged laying hens, with a comprehensive economic analysis of parasite impact.

Establishment and spread of Ornithonyssus sylviarum were documented through time on sentinel hens (50 per house of 28,000-30,000 hens) in the first egg production cycle of three large commercial flocks (12 houses) of white leghorn hens. Mites were controlled using acaricide, and the impacts of treatment on mite populations and economic performance were documented. Mite prevalence and intensity increased rapidly and in tandem for 4-8 weeks after infestation.

Short report: comparison of oral infectious dose of West Nile virus isolates representing three distinct genotypes in Culex quinquefasciatus.

Phylogenetic analysis of West Nile virus in North America has identified replacement of the originally introduced clade, Eastern United States (NY99), by the North American clade. In addition, the transient emergence of other clades and genetic variants has also been observed. In this study, we investigated the potential role of the mosquito in the selection of these clades and genetic variants.

Growth characteristics of ChimeriVax-Den vaccine viruses in Aedes aegypti and Aedes albopictus from Thailand.

Four chimeric yellow fever (YF) 17D-dengue (DEN) candidate vaccine viruses (ChimeriVax-DEN; Acambis, Cambridge, MA) were characterized in Aedes aegypti and Ae. albopictus mosquitoes collected from Thailand. The four vaccine viruses contained the relevant prM and E genes of wild-type dengue viruses (DENV; serotypes 1-4) substituted for the equivalent genes in the YF vaccine virus (17D) backbone.

Determinants of vector specificity of o'nyong nyong and chikungunya viruses in Anopheles and Aedes mosquitoes.

The alphaviruses o'nyong nyong virus (ONNV) and chikungunya virus (CHIKV) provide a unique system to study the viral genes involved in vector specificity. ONNV infects both anopheline and culicine mosquitoes, whereas CHIKV infects only culicine mosquitoes. In this study, chimeric viruses were constructed that contained genes from both ONNV and CHIKV.

Nonviremic transmission of West Nile virus.

West Nile virus (WNV) is now the predominant circulating arthropod-borne virus in the United States with >15,000 human cases and >600 fatalities since 1999. Conventionally, mosquitoes become infected when feeding on viremic birds and subsequently transmit the virus to susceptible hosts. Here, we demonstrate nonviremic transmission of WNV between cofeeding mosquitoes.

West Nile virus dissemination and tissue tropisms in orally infected Culex pipiens quinquefasciatus.

We investigated the spatial and temporal distribution of West Nile virus (WNV) in organs and tissues of Culex pipiens quinquefasciatus mosquitoes for up to 27 days following oral infection. WNV antigen was detected in paraffin-embedded mosquitoes by immunohistochemistry. Immunofluorescence assays were performed on dissected salivary glands and midguts and analyzed by confocal microscopy.