The larvicidal activity of 4 plant essential oils--innamon oil, lemon eucalyptus oil, sandalwood oil, and turmeric oil--previously reported as insect repellents was evaluated in the laboratory against 4th instars of Aedes albopictus, Ae. aegypti, and Culex pipiens. Sandalwood oil appeared to be the most effective of the larvicides, killing larvae of all 3 mosquito species in relatively short times. The values of LT50 and LT90 at the application dosage (0.2 mg/ml) were 1.06 +/- 0.11 and 3.24 +/- 0.14 h for Ae. aegypti, 1.82 +/- 0.06 and 3.33 +/- 0.48 h for Ae. albopictus, and 1.55 +/- 0.07 and 3.91 +/- 0.44 h for Cx. pipiens, respectively. Chemical compositions of these essential oils were also studied, and the lavicidal activity of their major ingredient compounds was compared with that of each of the essential oils. The acute toxicity of the 4 essential oils to fathead minnows was also evaluated. The safe use of these natural plant essential oils in future applications of mosquito control was discussed.

The West Nile virus (WNV) viremia and shedding profiles of 11 adult fox squirrels (Sciurus niger) infected by needle inoculation or mosquito bite were characterized. Daily mean titers (95% confidence intervals) for all squirrels on days 1 through 6 postexposure (p.e.) were: 10(1.7(1.3-2.1)), 10(4.4(4.0-4.8)), 10(5.3(5.0-5.6)), 10(4.4(3.9-4.9)), 10(2.7(2.0-3.4)), and 10(1.1(0.5-2.1)) plaque-forming units (PFU)/mL. The highest WNV serum titers of individual squirrels infected by needle inoculation or mosquito bite ranged from 10(4.5) to 10(6.1) and from 10(5.1) to 10(5.3) PFU/mL, respectively. Nine (82%) squirrels, including all 4 squirrels infected by mosquito bite, had WNV serum titers >= 10(5.1) PFU/mL that persisted on average for 1.6 +/- 0.3 days. Infection and dissemination rates of Culex pipiens (L.) that fed on squirrels with serum titers of 10(4.4 +/- 0.1) PFU/mL were 56% and 13%, respectively. Both of these rates increased to over 80% when fed on squirrels with a mean WNV titer of 10(5.5 +/- 0.1) PFU/mL. Infection and dissemination also occurred in Aedes triseriatus (Say) but at a much lower rate. WNV was isolated from the oral and rectal cavities of all squirrels and from urine that was opportunistically collected from 5 squirrels. The largest quantity of WNV recovered from swabs of the oral cavity and urine was 10(3.1) PFU. The longest periods after exposure that WNV was isolated from the oral cavity and urine from a squirrel were 22 and 17 days p.e., respectively. WNV RNA was also detected in kidney tissue in 1 squirrel 29 days p.e., suggesting that fox squirrels can be persistently infected. Collectively these observations provide further evidence that squirrels can contribute to the natural history and epidemiology of WNV, especially in peridomestic environments.

During 2006, mosquitoes were collected at the Western Research Farm, Castana, and McNay Research Farm, Chariton, IA in gravid traps that were baited to attract female mosquitoes that were ready to lay eggs (oviposit).The gravid trap in particular is in widespread use in mosquito control programs throughout the U.S., because the trap preferentially attracts mosquitoes that 1) are known vectors (in the genus Culex) of West Nile virus (WNV) and St. Louis Encephalitis virus (SLEV) and 2) have taken a potentially infectious blood meal (prerequisite to oviposition), thereby increasing the chance of detecting virus.Specimens were collected daily and kept cold to maintain integrity, then were mailed to campus.Once in the lab, specimens were identified to species and vector species were pooled into groups of up to 50-a standard operating procedure for surveillance labs across the U.S.-which then were subjected to virus detection assays.The results of trapping at these sites are shown according to the species of mosquitoes collected.Mosquitoes in the genus Culex (Cx. in table 1) were subjected to virus detection assays, and none of those collected at either farm tested positive for infection with WNV or SLEV. Results and DiscussionInterestingly, these traps attracted a number of Aedes triseriatus, the Eastern tree hole mosquito, so called because they oviposit in tree holes.This mosquito is extremely significant in terms of public health, because they transmit La Crosse encephalitis virus (LACV), which causes

Mosquito population dynamics have been monitored on an annual basis in the state of Iowa since 1969. The primary goal of this project was to integrate light trap data from these efforts into a centralized back-end database and interactive website that is available through the internet at http://iowa-mosquito.ent.iastate.edu. For comparative purposes, all data were categorized according to the week of the year and normalized according to the number of traps running. Users can readily view current, weekly mosquito abundance compared with data from previous years. Additional interactive capabilities facilitate analyses of the data based on mosquito species, distribution, or a time frame of interest. All data can be viewed in graphical and tabular format and can be downloaded to a comma separated value (CSV) file for import into a spreadsheet or more specialized statistical software package. Having this long-term dataset in a centralized database/website is useful for informing mosquito and mosquito-borne disease control and for exploring the ecology of the species represented therein. In addition to mosquito population dynamics, this database is available as a standardized platform that could be modified and applied to a multitude of projects that involve repeated collection of observational data. The development and implementation of this tool provides capacity for the user to mine data from standard spreadsheets into a relational database and then view and query the data in an interactive website.

Infection of mice with sporozoites of Plasmodium berghei or Plasmodium yoelii has been used extensively to evaluate liver-stage protection by candidate preerythrocytic malaria vaccines. Unfortunately, repeated success of such vaccines in mice has not translated readily to effective malaria vaccines in humans. Thus, mice may be used better as models to dissect basic parameters required for immunity to Plasmodium-infection than as preclinical vaccine models. In turn, this basic information may aid in the rational design of malaria vaccines. Here, we describe a model of circumsporozoite-specific memory CD8 T cell generation that protects mice against multiple P. berghei sporozoite challenges for at least 19 months. Using this model we defined a threshold frequency of memory CD8 T cells in the blood that predicts long-term sterilizing immunity against liver-stage infection. Importantly, the number of Plasmodium-specific memory CD8 T cells required for immunity greatly exceeds the number required for resistance to other pathogens. In addition, this model allowed us to identify readily individual immunized mice that exceed or fall below the protective threshold before infection, information that should greatly facilitate studies to dissect basic mechanisms of protective CD8 T cell memory against liver-stage Plasmodium infection. Furthermore, the extremely large threshold in memory CD8 T cell frequencies required for long-term protection in mice may have important implications for development of effective malaria vaccines.

Background West Nile virus (WNV) emerged as a threat to public and veterinary health in the Midwest United States in 2001 and continues to cause significant morbidity and mortality annually. To investigate biotic and abiotic factors associated with disease incidence, cases of reported human disease caused by West Nile virus (WNV) in the state of Iowa were aggregated by census block groups in Iowa for the years 2002–2006. Spatially explicit data on landscape, demographic, and climatic conditions were collated and analyzed by census block groups. Statistical tests of differences between means and distributions of landscape, demographic, and climatic variables for census block groups with and without WNV disease incidence were carried out. Entomological data from Iowa were considered at the state level to add context to the potential ecological events taking place. Results Numerous statistically significant differences were shown in the means and distributions of various landscape and demographic variables for census block groups with and without WNV disease incidence. Census block groups with WNV disease incidence had significantly lower population densities than those without. Landscape variables showing differences included stream density, road density, land cover compositions, presence of irrigation, and presence of animal feeding operations. Statistically significant differences in the annual means of precipitations, dew point, and minimum temperature for both the year of WNV disease incidence and the prior year, were detected in at least one year of the analysis for each parameter. However, the differences were not consistent between years. Conclusion The analysis of human WNV disease incidence by census block groups in Iowa demonstrated unique landscape, demographic, and climatic associations. Our results indicate that multiple ecological WNV transmission dynamics are most likely taking place in Iowa. In 2003 and 2006, drier conditions were associated with WNV disease incidence. In a significant novel finding, rural agricultural settings were shown to be strongly associated with human WNV disease incidence in Iowa.

Objective To select West Nile virus(WNV) quick detecting methods from mosquitoes which can be used in China. Methods Two methods, ADAPCO's RAMP System and MAS's VecTest kits were selected. The sensitivity and accuracy of these two methods and its cross-reaction with Japanese Encephalitis virus were tested. These two methods also were used to detect WNV in wild mosquitoes. Results The results show that both of the two methods can be used to detect WNV. Ramp system is more sensitive than VecTest kits. RT-PCR confirmed that no false positive and false negative results were obtained. These two methods have no cross-reaction in detecting WNV and Japanese Encephalitis virus. 6 species of wild mosquitoes were detected by these two methods. No WNV was found. Conclusion Both of Ramp system and VecTest can be used to detect WNV.

The larvicidal activity and repellency of 5 plant essential oils--thyme oil, catnip oil, amyris oil, eucalyptus oil, and cinnamon oil--were tested against 3 mosquito species: Aedes albopictus, Ae. aegypti, and Culex pipiens pallens. Larvicidal activity of these essentials oils was evaluated in the laboratory against 4th instars of each of the 3 mosquito species, and amyris oil demonstrated the greatest inhibitory effect with LC50 values in 24 h of 58 microg/ml (LC90 = 72 microg/ml) for Ae. aegypti, 78 microg/ml (LC90 = 130 microg/ml) for Ae. albopictus, and 77 microg/ml (LC90 = 123 microg/ml) for Cx. p. pallens. The topical repellency of these selected essential oils and deet against laboratory-reared female blood-starved Ae. albopictus was examined. Catnip oil seemed to be the most effective and provided 6-h protection at both concentrations tested (23 and 468 microg/ cm2). Thyme oil had the highest effectiveness in repelling this species, but the repellency duration was only 2 h. The applications using these natural product essential oils in mosquito control are discussed.

Purpose: The objective of this study was determine the range of forces encountered during surgical insertion of osteochondral autografts and the effect on cellular viability and matrix degeneration. Methods: Osteochondral graft transplantation was performed in fresh frozen cadaveric knees. Forces required to extrude the cartilage from the harvester device, seat the cartilage flush with the surrounding cartilage and recess the cartilage 2 mm into the recipient site were measured using a uniaxial load cell. These forces were then applied to osteochondral grafts obtained form six fresh human femoral condyles harvested from total knee arthroplasty cases and one fresh normal knee. Applied loads varied from zero (sham) to 800 newtons. Chondrocyte viability and glycosaminoglycan release was determined at 48 and 120 hours post impact. Results: Graft insertion forces were relatively low (<400 newtons) during insertion or seating the graft compared to recession of the graft in the recipient site (max 800 newtons). A mean of 91% of the cells were viable in unimpacted grafts from the total knee specimens and nearly 100% for the fresh normal knee. Total knee specimens demonstrated 50% decreased in viability at 800N (P < .01). The fresh normal specimen demonstrated a significant decrease in viability approaching 20% at 400N and 800N (P < .01) at 120 hours post impact. Glycosaminoglycan release did not correlate significantly with insertion loads although there was a trend toward increased release with higher loads at 120 hours. Conclusions: Typical insertion loads for osteochondral grafting may not be immediately harmful to the cartilage implant but recession or placement of a graft into a relatively shorter recipient hole may reduce cellular viability in the graft.

Rotator cuff integrity after repair is a major determinant of a good functional result and residual deficiencies have been found in greater than 50% of complex tears. Different modes of suture anchor failure have been identified and may occur due to anchor displacement or pullout, suture breakage, knot slippage, or suture pulling though the tendon. Recently, another mode of anchor failure has been identified in the bovine model by suture cutting though the bone when an anchor is placed deeper than recommended. However, this result has not been reproduced using human cadaveric shoulders. The purpose of this study was to evaluate the biomechanical stability of a suture anchor placed deep within the rotator cuff footprint of human cadaver humeri. Methods: Metallic screw-in anchors loaded with a single, number 2 braided nonabsorbable polyester suture were placed in the infraspinatus footprint of eight human cadaver humeri (87 ± 3 years) at two depths. Standard placement had the threads countersunk 3 mm below the bone surface. The deep anchors doubled this depth to 6 mm. The sutures were placed under 10 N of preload and the knots were placed equidistant from the bone hole exit and a smooth metallic rod used for mechanical testing. Specimens were cyclically loaded between 10 to 45 N to a maximum of 500 cycles and then, if still intact, loaded at 0.5 mm/sec to failure. Total displacement after cyclic testing (mm) and ultimate failure load (N) were analyzed with a one-way ANOVA (P < .05). Failure mode and location were recorded after testing. Results: The total displacement after cyclic loading was significantly different between repair depths. The deep anchors attained a total displacement of 8.4 ± 2.4 mm while the standard anchors had a final displacement of 5.7 ± 1.4 mm (P < .03). There was no difference in ultimate failure load between depths, with the deep anchors failing at 144 ± 14 N and standard anchors failing at 143 ± 13 N. The deep anchors were noted to translate to the cortical margin within the first few cycles. Both anchor positions seemed to rotate at the cortical surface due to the orientation of loading as testing progressed. Failure occurred at the eyelet in two tests, while the remaining tests exhibited anchor translation/rotation and some suture cut through. Discussion: Burying suture anchors beyond the specified insertion depth is inadvisable based on these data. Excessive anchor depth may lead to early clinical failure by the suture cutting through bone. Both anchor depths displayed rotation and translation at the cortical surface and some migrated above the joint surface during physiologic cyclic loading. The rotation and translation may induce early deficiencies in the cuff repair while the migration may limit joint range of motion and induce joint arthrosis. Due to poor bone quality, these rotations/translations are of specific concern in the osteoporotic population. Improved anchor eyelet designs may lessen the possibility of abrasive degradation of the suture, and abrasion-resistant materials may decrease the risk of suture fretting.