Biomedical subjects

Scott M Shone

Publications and source records attributed to Scott M Shone.

6 recordsLinked to original sources

PubMed2006

A novel real-time PCR assay for the speciation of medically important ticks.

The identification of ticks using morphological characters is a well-established practice, however specimens that are small or damaged are often difficult to speciate. A novel, rapid real-time PCR assay, which targets the second internal transcribed spacer (ITS2) region in the nuclear ribosomal DNA gene, was developed for identification of four tick species of utmost medical importance in the United States: Ixodes scapularis, I. pacificus, Dermacentor variabilis, and Amblyomma americanum. Computational analyses of public databases and DNA sequencing studies revealed regions that could be specifically targeted with oligonucleotides optimized for TaqMan chemistry. The oligonucleotide sets designed in this study are specific at both the genus and species levels, and are sensitive at 0.1-1 pg of total tick DNA.

Animals↗

PubMed2006

Targeted trapping of mosquito vectors in the Chesapeake Bay area of Maryland.

Most adult mosquito surveillance in Maryland is performed using dry ice-baited or unbaited Centers for Disease Control (CDC) miniature light traps suspended approximately 1.5 m above the ground. However, standardized trapping methods may miss mosquito species involved in disease transmission cycles. During a 2-yr study, the effectiveness of the olfactory attractant 1-octen-3-ol alone and in combination with carbon dioxide was evaluated for collecting mosquito vector species. In addition, trap heights were examined to determine the optimal vertical placement to target various species. We evaluated the results during the second year by targeting selected species by using various habitat- height-bait combinations. Although Culex erraticus Dyar & Knab and Anopheles quadrimaculatus Say were not successfully targeted, Culex salinarius Coquillett, Aedes vexans Meigen, Anopheles bradleyi/crucians King, Coquillettidia perturbans Walker, Aedes sollicitans Walker, and Aedes taeniorhynchus Wiedemann were preferentially captured using targeted trapping schemes.

Animals↗

PubMed2006

Characterizing population dynamics of Aedes sollicitans (Diptera: Culicidae) using meteorological data.

Numerous studies have investigated the role of weather on insect species. For mosquitoes, these studies have yielded mixed results. Although it is clear that weather impacts mosquito population dynamics, these investigations have failed to accurately characterize their fluctuations. We use a novel graphical method to examine large numbers of meteorological aggregations of varying lengths and lags simultaneously to establish relationships between these summary variables and mosquito counts, to gain a better understanding of the weather effects. Poisson regression models were developed to characterize the population dynamics of Aedes sollicitans (Walker) by using meteorological data and a 34-yr set of daily mosquito count data. The models accurately characterize mosquito dynamics over time and space. The aggregated meteorological variables included in the model were lowest minimum tides between days 27 and 14 before trapping, total precipitation between days 22 and 9, total precipitation on day 1 and the day of trapping, cooling degree-days on day 0, average minimum relative humidity between days 28 and 9, lowest stream flow from day 11 to day 0, and lowest minimum temperature between days 28 and 13.

Aedes↗

PubMed2005

Cross correlation maps: a tool for visualizing and modeling time lagged associations.

It has long been recognized that arthropod populations fluctuate with changes in environmental conditions and these changes occur at various spatial and temporal scales. Empirical studies that have explored associations between vector abundance and the environment often considered meterological events as leading indicators with their effects traditionally restricted to single points in time, such as precipitation 12 days prior to trapping. Field experience, however, suggests that the duration of these environmental effects on vectors often extends over a range or interval of time. Such a scenario is not directly interpretable from cross correlation plots routinely employed to visualize and identify time lag associations. Cross correlation maps are introduced as a way to generalize cross correlation plots and to visualize the effects of environmental conditions over intervals of time. This graphical method is flexible and can include different characterizations of environmental effects, as well as interactions among environmental variables. A time series of daily trapped female Ochlerotatus sollicitans mosquitos and leading meterologic conditions were used for demonstration. Associations shown in cross correlation maps were consistent with the arthropod biology and trapping efficacy and were also stronger than those identified at single time points using cross correlation plots. Poisson regression models for vector abundance built using meterological variables with both single and interval based leading time lags were compared. The approach based on the leading meterological events allowed to extend over time intervals reproduced the Oc. sollicitans daily population dynamics better than the traditional approach.

Animals↗

PubMed2004

Wounding: the primary mode of Seoul virus transmission among male Norway rats.

In rodent populations, males are more likely to be infected with hantaviruses and to engage in aggression than are females. To assess the relationship between aggression and Seoul virus infection, Norway rats were trapped in Baltimore, Maryland and wounding, infection status, and steroid hormone concentrations were examined. Older males and males with high-grade wounds were more likely to have IgG antibody to Seoul, to shed virus in saliva, urine, and feces, and to have viral RNA in organs than either juveniles or adult males with less severe wounds. In contrast, neither age nor wounding predicted virus shedding among females. Although viral antigen was not identified in the brain, viral protein was detected in the gonads and adrenal glands of adult males. Males with more severe wounds had higher testosterone concentrations than males with no or low-grade wounds. Because wounding, testosterone, and virus shedding are associated among males, aggression may be the primary mode of Seoul virus transmission among male, but not female, Norway rats.

Aggression↗

PubMed2003

Evaluation of carbon dioxide- and 1-octen-3-ol-baited Centers for Disease Control Fay-Prince traps to collect Aedes albopictus.

During the summer of 2001, field studies were performed to evaluate the effects of carbon dioxide (CO2) and 1-octen-3-ol (octenol) on the ability to collect Aedes albopictus with Centers for Disease Control (CDC) Fay-Prince traps. Results from these studies indicated that Ae. albopictus is significantly more attracted to CO2- or CO2 + octenol-baited CDC Fay-Prince traps than unbaited or octenol-baited traps. However, the difference between the responses to CO2 and CO2 + octenol was not statistically different, indicating that CO2 is driving the response of Ae. albopictus to CDC Fay-Prince traps.

Aedes↗