Taming a tiger in the city: comparison of motorized backpack applications and source reduction against the Asian tiger mosquito, Aedes albopictus.

We evaluated 2 strategies to manage Aedes albopictus: 1) motorized backpack applications and 2) source reduction (coupled with hand-applied applications of larvicide). Backpack applications used a water-dispersible granular formulation (VectoBac WDG) of Bacillus thuringiensis var. israelensis (Bti), whereas source reduction used granular formulations of the insect growth regulator methoprene (Altosid) combined with a monomolecular film surfactant (Agnique). Six subplots (total 8.02 ha) were selected for backpack applications, source reduction, and control groups. The experiments were blind with applications conducted randomly and independently. Efficacy was determined through placement of bioassay cups with larvae within experimental plots 1 day before treatment. Backpack applications resulted in 76% (+/- 8.2% SE) and source reduction resulted in 92% (+/- 4.1% SE) larval mortality. Backpack applications required 50 times less labor than source reduction (0.25 versus 0.005 ha/h). The cost of backpack applications, including labor, was $159.88/ha, compared with $659.65/ha for source reduction. Although overall efficacy was slightly lower, motorized backpack applications of Bti were more efficient and cost-effective than source reduction methods to control Ae. albopictus in urban settings at the community level.

Suppression of Amblyomma americanum (Ixodida: Ixodidae) for short-term field operations utilizing cypermethrin and lambda-cyhalothrin.

Tick-borne diseases pose significant risks to U.S. military personnel who conduct operations, both domestic and abroad. To determine the feasibility of protecting personnel from tick vectors during short-term field deployments, acaricides cypermethrin (Demon WP, Syngenta, Greensboro, NC) and lambda-cyhalothrin (Surrender Pestabs, CSI, Pasadena, TX) were applied to plots within two separate field sites on Camp Blanding Joint Training Center in Starke, FL, from May to June 2011. We analyzed their effectiveness in reducing tick counts for 6 wk after application. In total, 8,193 ticks were identified and counted, of which > 99% were a mix of nymphs and adult-stage Amblyomma americanum (L.). Our results indicate that both cypermethrin and lambda-cyhalothrin were effective in significantly reducing tick numbers and preventing entry into treated plots for 6 wk after application. Thus, these two acaracides can be used to effectively suppress tick populations and provide residual protection in small geographic areas of recreation or public health significance.

Temporal and storage effects on ultra-low volume droplets of insecticides collected on Teflon-coated slides.

Use of microscope slides is the most commonly used method to field-assess the droplet spectrum of ultra-low volume (ULV) sprays. Due to absence of analysis facilities during military deployments, slides must be stored and shipped, and the impact of delays in processing and storage conditions on droplets is unknown. This study was designed to evaluate the effect of storage temperatures and duration on droplets on Teflon-coated slides. Treatments included BVA-13 mineral oil, Kontrol 30-30 (30% permethrin), and Fyfanon (96.5% malathion), 2 slide wrapping techniques (proper and improper), and 2 storage temperatures (23 and 45 degrees C), replicated 6 times. The same areas of a slide were measured at different times for 56-58 days using the DropVision droplet measurement system. Regardless of the wrapping technique, droplets of BVA-13, Fyfanon, and Kontrol 30-30 on slides stored at 45 degrees C reduced significantly after 1, 2, and 1 day, respectively, but droplets on slides stored at 23 degrees C were not significantly affected. The results of this study may assist vector control professionals to accurately interpret the droplet size and help in the effective dispersal of ULV-applied insecticides.

Larval mosquito habitat utilization and community dynamics of Aedes albopictus and Aedes japonicus (Diptera: Culicidae).

Aedes albopictus (Skuse) and Ae. japonicus (Theobald) are important container-inhabiting mosquitoes that transmit disease agents, outcompete native species, and continue to expand their range in the United States. Both species deposit eggs in natural and artificial containers and thrive in peridomestic environments. The goal of our study was to examine the types and characteristics of containers that are most productive for these species in the northeastern United States. In total, 306 containers were sampled in urban, suburban, and rural areas of New Jersey. Multiple biotic and abiotic factors were recorded in an attempt to identify variables associated with the productivity of each species. Based on pupal abundance and density of container types, results showed that tires, trash cans, and planter dishes were the most important containers for Ae. albopictus, while planter dishes were the most important containers for Ae. japonicus. Container color (black and gray), material (rubber), and type (tires) were correlated with species presence for Ae. albopictus and Ae. japonicus. These factors may play a role in the selection of oviposition sites by female mosquitoes or in the survival of their progeny. Differences in species composition and abundance were detected between areas classified as urban, suburban, and rural. In urban and suburban areas, Ae. albopictus was more abundant in container habitats than Ae. japonicus; however, Ae. japonicus was more abundant in rural areas, and when water temperatures were below 14 degrees C. Our results suggest many variables can influence the presence of Ae. albopictus and Ae. japonicus in container habitats in northeastern United States.

Efficacy of ovitrap colors and patterns for attracting Aedes albopictus at suburban field sites in north-central Florida.

We sought to visually enhance the attractiveness of a standard black ovitrap routinely used in surveillance of the Asian tiger mosquito, Aedes albopictus, and now being used as lethal ovitraps in Ae. aegypti dengue control programs. Black plastic drinking cups (ovitraps) were visually altered to offer field populations of gravid female Ae. albopictus 6 different oviposition site choices. Trials were conducted at 3 field locations in Gainesville, Orange Park, and Jacksonville, FL, during July-August 2009. A black glossy cup served as the control and was tested against 5 cup choices consisting of white, blue, orange, or black-and-white contrasting patterns (checkered or vertically striped). Means (SE) of eggs collected over 6 wk for each choice were: black 122.53 (9.63) > blue 116.74 (10.74) > checkered 101.84 (9.53) > orange 97.15 (7.95) > striped 84.62 (8.17) > white 81.84 (8.74). Black ovitraps outperformed competing colored and contrasting patterned ovicups with respect to choice from gravid Ae. albopictus seeking artificial oviposition sites.

Occurrence of avian Plasmodium and West Nile virus in Culex species in Wisconsin.

The occurrence of multiple pathogens in mosquitoes and birds could affect the dynamics of disease transmission. We collected adult Culex pipiens and Cx. restuans (Cx. pipiens/restuans hereafter) from sites in Wisconsin and tested them for West Nile virus (WNV) and for avian malaria (Plasmodium). Gravid Cx. pipiens/restuans were tested for WNV using a commercial immunoassay, the RAMP WNV test, and positive results were verified by reverse transcriptase-polymerase chain reaction. There were 2 WNV-positive pools of Cx. pipiens/restuans in 2006 and 1 in 2007. Using a bias-corrected maximum likelihood estimation, the WNV infection rate for Cx. pipiens/restuans was 5.48/1,000 mosquitoes in 2006 and 1.08/1,000 mosquitoes in 2007. Gravid Cx. pipiens or Cx. restuans were tested individually for avian Plasmodium by a restriction enzyme-based assay. Twelve mosquitoes were positive for avian Plasmodium (10.0%), 2 were positive for Haemoproteus, and 3 were positive for Leucocytozoon. There were 4 mixed infections, with mosquitoes positive for > 1 of the hemosporidian parasites. This work documents a high rate of hemosporidian infection in Culex spp. and illustrates the potential for co-infections with other arboviruses in bird-feeding mosquitoes and their avian hosts. In addition, hemosporidian infection rates may be a useful tool for investigating the ecological dynamics of Culex/avian interactions.

First records of Aedes japonicus japonicus in Wisconsin.

Aedes japonicus japonicus was collected via gravid trapping in Wisconsin in the summers of 2004 and 2005 at Fort McCoy, Monroe County. Subsequently, in the summer of 2007, Ae. japonicus was captured in a human landing catch in Dane County, Madison, WI. Additional collections were made at this site in the spring of 2008. Invasion is in progress, but significant population increases have not yet been confirmed.

A retrospective study of the association between megestrol acetate administration and mortality among nursing home residents with clinically significant weight loss.

BACKGROUND: Megestrol acetate (MA) is a progestin widely used to treat weight loss and cachexia in patients suffering from AIDS or cancer. Although MA is also frequently prescribed for similarly malnourished elderly individuals, the efficacy and morbidity of MA treatment in this patient population remain unclear. OBJECTIVE: The goal of this study was to examine the effects of MA therapy on weight and overall mortality in elderly nursing home residents. METHODS: This was a case-control cohort study of 17,328 nursing home residents admitted to Beverly Healthcare nursing home between January 1, 2000, and December 31, 2003, who had lost either 5% of total body weight within 3 months or 10% of total body weight within 6 months. Residents within this weight loss group who received MA therapy--within 30 days of their weight loss documentation--were matched (1:2) with non-MA-treated residents with respect to age, sex, race, weight, and first notation of weight loss. Residents were further matched by propensity score for activities of daily living, cognitive functioning, number of medications taken during the 7 days before data entry, clinical condition (unstable, acute episode of a recurrent problem, end-stage disease), cancer diagnosis, and human immunodeficiency virus diagnosis. RESULTS: A total of 709 patients (mean [SD]age, 84.1 [9.7]years; 70.9% female) who received MA therapy were matched with 1418 non-MA-treated patients (mean [SD] age, 84.2 [9.0] years; 70.9% female). Of the 709 MA patients, 281 (39.6%) were alive and in the nursing home at last follow-up, 149 (21.0%) were alive and discharged to another facility or to home, and 279 (39.4%) died in the nursing home. For the controls, 651 (45.9%) were alive and in the nursing home, 308 (21.7%) were discharged to another facility or to home, and 459 (32.4%) died in the nursing home. The median survival of MA-treated residents (23.9 months; 95% CI, 20.2-27.5) was significantly less than untreated residents (31.2 months; 95% CI, 27.8-35.9) (P < 0.001). Median weight and median of weight differences were unchanged after 6 months of treatment with MA compared with matched controls. CONCLUSIONS: MA treatment of elderly nursing home residents with significant weight loss was associated with a significant increase in all-cause mortality without a significant increase in weight. Randomized, prospective studies of the use of MA in elderly nursing home residents are necessary to more fully evaluate morbidity and mortality associated with this therapy.