Journal of Vector Ecology最新文献

Sylvatic plague, caused by the bacterium Yersinia pestis and transmitted by fleas, occurs in prairie dogs of the western United States. Outbreaks can devastate prairie dog communities, often causing nearly 100% mortality. Three competent flea vectors, prairie dog specialists Oropsylla hirsuta and O. tuberculata, and generalist Pulex simulans, are found on prairie dogs and in their burrows. Fleas are affected by climate, which varies across the range of black-tailed prairie dogs (Cynomys ludovicianus), but these effects may be ameliorated somewhat due to the burrowing habits of prairie dogs. Our goal was to assess how temperature and precipitation affect off-host flea abundance and whether relative flea abundance varied across the range of black-tailed prairie dogs. Flea abundance was measured by swabbing 300 prairie dog burrows at six widely distributed sites in early and late summer of 2016 and 2017. Relative abundance of flea species varied among sites and sampling sessions. Flea abundance and prevalence increased with monthly mean high temperature and declined with higher winter precipitation. Predicted climate change in North America will likely influence flea abundance and distribution, thereby impacting plague dynamics in prairie dog colonies.

Most mosquito species are active during a certain part of the day, but climatic factors such as light intensity and relative humidity play an important role in the control of their activity. We selected three types of land use that were sampled in state of Campeche in 2018 (low semi-evergreen forest, secondary low semi-evergreen forest, and mango plantation), using ten CDC light traps baited with CO₂, that were active during nine hours of three activity periods (dawn, noon, and nightfall). A GLM was used to investigate changes in the assembly of mosquitoes between different types of land use and temporal variations. Rank abundance curves were used to detect changes in the spatial and activity period of the mosquitoes and we then calculated the Exponential Shannon Index. A total of 6,110 mosquitoes belonging to 23 species were captured. The greatest richness and abundance were found in the secondary low semi-evergreen forest, with greater richness and lower abundance than the mango plantation which showed more abundance. Of the activity periods, dusk had the greatest abundance and richness followed by dawn and finally noon.

Resistance to pyrethroids (PY) and organophosphate (OP) insecticides is widespread among populations of Culex quinquefasciatus, the major vector of lymphatic filariasis (LF). The present study was designed to detect the L1014F kdr (knockdown resistant) mutation among Cx. quinquefasciatus populations in the filarial belt of Sri Lanka. Mosquitoes were reared from field-caught larvae from seven localities where LF is endemic. Susceptibility status of Cx. quinquefasciatus to adulticides, 0.05% deltamethrin, 0.75% permethrin, 5% malathion, and the larvicide temephos was determined using the standard WHO susceptibility tests. A fragment of vgsc gene was amplified and sequenced to identify the responsible kdr mutations. The susceptibility test results revealed less than 90% mortalities for 0.05% deltamethrin, and 0.75% permethrin and temephos. For 5% malathion, all study sites except Maharagama revealed greater than 90% mortality. The L1014F kdr mutation was observed in all studied populations. Although the overall microfilaria rate is less than 1% in the country, there is a high risk of re-emergence of LF in Sri Lanka due to abundant Cx. quinquefasciatus mosquitoes, increased resistant status to currently used insecticides, imported LF cases, higher rates of microfilaria among neighboring countries, and the advancement of tourism.