First Record of an Established Population of Triatoma sanguisuga (Hemiptera: Reduviidae) in Richardson County, Nebraska.

In 2017, a single adult Triatoma sanguisuga (LeConte) (Hemiptera: Reduviidae) was identified from Indian Cave State Park in Nemaha County, NE. The following summer, a single adult specimen was found in a 4-H insect collection at the Nebraska State Fair from Richardson County. A subsequent investigation found that these were collected from a residence in Richardson County and three more adults were collected in 2019. In 2020, the latter three kissing bugs were submitted to Public Health Command-Central's DoD Food Analysis and Diagnostic Laboratory (DOD FADL) for confirmatory species identification and diagnostic testing for Trypanosoma cruzi, the causative agent of Chagas disease. One specimen tested positive for T. cruzi using a real-time dual-target PCR screen followed by confirmatory dual-target traditional PCR. Based on these findings, a survey plan was developed for Richardson and surrounding counties in southeast Nebraska. In July of 2020, two adult and seven nymphs (multiple instars) of T. sanguisuga were collected in Richardson County, one of which tested positive for T. cruzi. This is the first record of an established population of T. sanguisuga and T. cruzi-infected kissing bugs in Nebraska.

Annotated world checklist of the Trombiculidae and Leeuwenhoekiidae (17582021) (Acari: Trombiculoidea), with notes on nomenclature, taxonomy, and distribution.

The superfamily Trombiculoidea is a large and diverse group of acarines that comprises six families; of these, the families Trombiculidae and Leeuwenhoekiidae are characterized by larvae commonly known as chiggers that are parasites of terrestrial vertebrates, including humans, and some species are of medical importance as vectors of chigger-borne rickettsiosis (scrub typhus), caused by the rickettsia Orientia tsutsugamushi. This paper presents an annotated checklist of 3,013 generally accepted chigger species, together with their distribution by zoogeographic region, and a non-comprehensive list of synonyms. A total of 58 new combinations are proposed by transferring species to different genera, treating some subgenera as genera, or updating current generic names. The checklist updates earlier catalogs of the world chigger fauna, but because the literature on chigger taxonomy is voluminous and scattered, similar, regional monographs were utilized in constructing the classificatory foundation. This list may not contain every species, synonym or taxonomic rearrangement that has been published, but it reflects the most recent arrangement of chigger taxa. Distribution records are primarily drawn from collection sites listed in the original species descriptions, together with subsequently published geographical records.

First Records of Established Populations of Ixodes scapularis (Acari: Ixodidae) Collected From Three Nebraska Counties.

Reported cases of Lyme disease in Nebraska have been assumed to be imported from other endemic areas. Previous surveillance efforts provided no evidence of established populations as only individual specimens of Ixodes scapularis (Say) had been collected. In the winter of 2018, adult I. scapularis were found on a dog at Two Rivers State Recreation Area, Douglas County, prompting tick collection at the site and nearby natural areas. In May 2019, all life stages of host-seeking I. scapularis were collected using dragging and flagging techniques in sites located near the Platte River in Douglas, Sarpy, and Saunders counties. This is the first documentation of established populations of I. scapularis in Nebraska.

Identification of Triatomines and Their Habitats in a Highly Developed Urban Environment.

Eleven triatomine species, the vector for Chagas disease, are endemic in the southern U.S. While traditionally thought to only occur in rural habitats and sylvatic transmission cycles, recent studies provide compounding evidence that triatomines could exist in urban habitats and domestic transmission cycles in Texas. We conducted a study of active and passive surveillance techniques over 3 years (2016-2018) in the City of Houston, Harris County, Texas to determine the presence of triatomines in this metroplex. Active surveillance methods uncovered Triatoma sanguisuga nymphs from two locations in downtown Houston city parks. We also documented the first Trypanosoma cruzi positive kissing bug collected in an urban environment of Harris County, Texas. Our findings provide evidence that triatomines can be found in heavily populated U.S. urban environments, and warrant public health support for expanded triatomine and Chagas disease surveillance in city settings.

Rickettsia parkeri and Rickettsia montanensis, Kentucky and Tennessee, USA.

We found that 14.3% (15/105) of Amblyomma maculatum and 3.3% (10/299) of Dermacentor variabilis ticks collected at 3 high-use military training sites in west-central Kentucky and northern Tennessee, USA, were infected with Rickettsia parkeri and Rickettsia montanensis, respectively. These findings warrant regional increased public health awareness for rickettsial pathogens and disease.

Home-based treadmill training to improve gait performance in persons with a chronic transfemoral amputation.

OBJECTIVE: To investigate the effectiveness of a home-based multiple-speed treadmill training program to improve gait performance in persons with a transfemoral amputation (TFA). DESIGN: Repeated measures. SETTING: Research laboratory. PARTICIPANTS: Individuals with a TFA (N=8) who had undergone a unilateral amputation at least 3 years prior as a result of limb trauma or cancer. INTERVENTION: Home-based treadmill walking for a total of 30 minutes a day, 3 days per week for 8 weeks. Each 30-minute training session involved 5 cycles of walking for 2 minutes at 3 speeds. MAIN OUTCOME MEASURES: Participants were tested pretraining and after 4 and 8 weeks of training. The primary measures were temporal-spatial gait performance (symmetry ratios for stance phase duration and step length), physiological gait performance (energy expenditure and energy cost), and functional gait performance (self-selected walking speed [SSWS], maximum walking speed [MWS], and 2-minute walk test [2MWT]). RESULTS: Eight weeks of home-based training improved temporal-spatial gait symmetry at SSWS but not at MWS. A relative interlimb increase in stance duration for the prosthetic limb and proportionally greater increases in step length for the limb taking shorter steps produced the improved symmetry. The training effect was significant for the step length symmetry ratio within the first 4 weeks of the program. Energy expenditure decreased progressively during the training with nearly 10% improvement observed across the range of walking speeds. SSWS, MWS, and 2MWT all increased by 16% to 20%. CONCLUSIONS: Home-based treadmill walking is an effective method to improve gait performance in persons with TFA. The results support the application of training interventions beyond the initial rehabilitation phase, even in individuals considered highly functional.

Effects of exercise training on the glutathione antioxidant system.

PURPOSE: The glutathione (GSH) antioxidant system has been shown to play an important role in the maintenance of good health and disease prevention. Various approaches have been used to enhance GSH availability including diet, nutritional supplementation, and drug administration, with minor to moderate success. Exercise training has evolved as a new approach. The purpose of this study was to investigate the effects of aerobic exercise training (AET), circuit weight training (CWT), and combined training (AET+CWT) on general adaptations, and resistance to acutely induced oxidative stress, as assessed by changes in the GSH antioxidant system. METHODS: Eighty healthy sedentary volunteers participated in the study who were randomly assigned to four groups: control (no exercise); AET, CWT, and AET+CWT. Exercise training programs were designed to simulate outpatient cardiac rehabilitation (40 min x 3 days x 6 weeks). Venous blood sampling was taken at rest and post maximal graded exercise test (GXT). A new improved spectrophotometric venous assay analysis technique was used. A mixed model repeated measures analysis of variance design was used with t-tests for preplanned comparisons evaluated at Bonferroni-adjusted alpha levels. RESULTS: Effectiveness of the exercise training programs was demonstrated by significant between-group (exercise group versus control) comparisons. AET, CWT, and AET+CWT showed significant pretraining-posttraining increases in resting GSH and glutathione-glutathione disulfide ratio (GSH:GSSG), and significant decreases in GSSG levels (P<0.005). AET+CWT showed the most pronounced effect compared with AET or CWT alone (P<0.025). CONCLUSION: This study represents the first longitudinal investigation involving the effects of multiple modes of exercise training on the GSH antioxidant system with evidence, suggesting the GHS:GSSG ratio as the most sensitive change marker. The significant findings of this study have potential clinical implications to individuals involved in cardiac and pulmonary rehabilitation.

Relationships among impairments in lower-extremity strength and power, functional limitations, and disability in older adults.

BACKGROUND AND PURPOSE: During the aging process, older adults may experience a loss of strength and power, which then may lead to functional limitations and disability. The purpose of this study was to examine how impairments in lower-extremity strength and power are related to functional limitations and disability in community-dwelling older adults. SUBJECTS: Thirty older adults (age [X+/-SD], 77.3+/-7.0 years; 25 women and 5 men) with mild to moderate functional limitations participated in this study. METHODS: Lower-extremity strength, peak power, power at a low relative intensity, and power at a high relative intensity were measured with a pneumatic resistance leg press. Functional limitations and disability were assessed with the Short Physical Performance Battery (SPPB), the Six-Minute Walk Test (SMWT), and the Late Life Function and Disability Instrument (LLFDI). RESULTS: All measures of strength and power were related to functional limitations. Peak power demonstrated the strongest relationships with SMWT, the SPPB gait speed subscale, and the LLFDI functional limitation component. Power at a high relative intensity demonstrated the strongest relationships to the SPPB total score and the SPPB sit-to-stand subscale score. All measures of strength and power were indirectly related to the LLFDI disability component. DISCUSSION AND CONCLUSION: Older adults should focus on increasing and maintaining lower-extremity strength and power across a range of intensities in order to decrease functional limitations and disability.

The effect of weighted vest walking on metabolic responses and ground reaction forces.

PURPOSE: This study examined how oxygen consumption, relative exercise intensity, vertical ground reaction forces (VGRF), and loading rate (LR) were affected while using a weighted vest (WV) during treadmill walking. METHODS: A sample of 10 (aged 23.4 +/- 1.7 yr) subjects performed a standardized walking test (4-min stages at 0.89, 1.12, 1.34, 1.56, and 1.79 m x s(-1)) on a treadmill under four weighted vest conditions (0, 10, 15, and 20% of body mass (BM)). Dependent variables included oxygen consumption (VO2), relative exercise intensity, first (F1) and second (F2) peaks of the VGRF curve, and LR. RESULTS: Repeated-measures ANOVA revealed significant vest versus speed interaction for V O2 and relative exercise intensity. Follow-up contrasts showed significant vest effect differences between 0% BM and all other WV conditions, and between 10 and 20% BM at all speeds for V O2. Follow-up analysis of relative exercise intensity demonstrated no significant vest effect difference at slower speeds, but significant differences at higher speeds. A significant main effect for WV condition was found for F1, F2, and LR. Follow-up testing revealed F1 and F2 at 0% BM were significantly different than at 10, 15, and 20% BM. F1 and F2 at 10% BM were significantly different than 20% BM, whereas F1 at 15% BM was significantly different than at 20% BM. LR at 0% BM was significantly different than at 15 and 20% BM. CONCLUSION: Using a weighted vest can increase the metabolic costs, relative exercise intensity, and loading of the skeletal system during walking.

The effects of prosthetic foot design on physiologic measurements, self-selected walking velocity, and physical activity in people with transtibial amputation.

OBJECTIVE: To investigate the physiologic differences during multispeed treadmill walking and physical activity profiles for the Otto Bock C-Walk foot (C-Walk), Flex-Foot, and solid ankle cushion heel (SACH) foot in people with transtibial amputation. DESIGN: A repeated-measures design with 3 prostheses. SETTING: Research laboratory. PARTICIPANTS: Eight men with unilateral transtibial amputation. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Physiologic responses (energy expenditure, gait efficiency, exercise intensity, rating of perceived exertion [RPE]) during multispeed treadmill walking (53.64, 67.05, 80.46, 93.87, 107.28 m/min) test were analyzed with 2-way repeated-measures analysis of variance (ANOVA). One-way ANOVA was employed to analyze foot-type differences for self-selected walking velocity (SSWV), and steps per day (daily activity). Analysis of covariance was used to analyze foot-type differences with SSWV as the covariable for the physiologic measurements. RESULTS: The C-Walk had a trend of improved physiologic responses compared with the SACH; however, no foot-type differences were statistically significant. Compared with the C-Walk and SACH, the Flex-Foot showed no significant differences in energy expenditure and gait efficiency, but significantly lower percentage of age-predicted maximum heart rate and RPE values. CONCLUSIONS: The energy storing-releasing feet appeared to have certain trends of improved gait performance compared with the SACH; however, not many objective foot-type differences were significantly noted. Further studies with a larger sample size are suggested.

Reliability and Accuracy of the AMP 331 for Activity Monitoring and Energy Expenditure Prediction in Young Adults.

BACKGROUND: A new triaxial accelerometer (AMP 331) provides a novel approach to understanding free-living activity through its ability to measure real time speed, cadence, and step length. This study examined the reliability and accuracy of the AMP 331, along with construction of prediction equations for oxygen consumption and energy cost. METHODS: Young adult volunteers (n = 41) wearing two AMP units walked and ran on a treadmill with energy cost data simultaneously collected through indirect calorimetry. RESULTS: Statistically significant differences exist in inter-AMP unit reliability for speed and step length and in accuracy between the AMP units and criterion measures for speed, oxygen consumption, and energy cost. However, the differences in accuracy for speed were very small during walking (≤ 0.16 km/h) and not clinically relevant. Prediction equations constructed for walking oxygen uptake and energy expenditure demonstrated R2 between 0.76 to 0.90 and between subject deviations were 1.53 mL O2 · kg-1 · min-1 and 0.43 kcal/min. CONCLUSIONS: In young adults, the AMP 331 is acceptable for monitoring walking speeds and the output can be used in predicting energy cost during walking but not running.

Effects of a maximal graded exercise test on glutathione as a marker of acute oxidative stress.

PURPOSE: Strenuous exercise in animal studies has been shown to cause acute oxidative stress due to the generation of oxygen-centered free radicals reflected in lower levels of glutathione (GSH), higher levels of glutathione disulfide (GSSG), and a drop in GSH:GSSG ratios, the maintenance of which is crucial for a variety of cell functions. Human studies on this topic are limited. The purpose of this study was to investigate the effects of a maximal graded exercise test GXTmax (modified Bruce protocol) on GSH as a marker of acute oxidative stress, and whether full recovery will occur at 60 minutes postexercise. METHODS: Eighty sedentary subjects were used as a sample of convenience. Venous blood samples for GSH and GSSG were collected directly before, immediately after, and 60 minutes post-GXTmax. Repeated-measures analysis of variance and Bonferroni adjusted t tests (post-GXTmax) versus resting, and 60 minutes recovery versus resting) were used for data analysis. RESULTS: As an acute response to maximal exercise, the GSH levels dropped significantly from a resting baseline value of 1025.75 microM to an immediate post-GXTmax value of 893.30 microM (pooled SE = 7.17 microM). The GSSG levels significantly increased from 2.24 microM to 3.15 microM (pooled SE = 0.03 microM). The GSH:GSSG ratio levels significantly dropped from baseline 462.12 to 276.40 postexercise (pooled SE = 5.98). The blood GSH, GSSG, and GSH:GSSG ratio levels showed no significant difference at 60 minutes post-GXTmax when compared with resting values, indicating full recovery. CONCLUSION: The current results indicated that in sedentary individuals, a maximal treadmill GXT is an effective technique for inducing acute oxidative stress as evidenced by GSH system responses, with full return to resting baseline levels within 60 minutes of recovery. The potential for using this model in assessing oxidative stress responses to cardiac and pulmonary rehabilitation is of clinical interest, with a need for further investigation.

The force-driven harmonic oscillator model for energy-efficient locomotion in individuals with transtibial amputation.

The force-driven harmonic oscillator (FDHO) model states that the driving force is minimum at the resonant period of an oscillator. By manipulating prosthetic mass, this study explored the compromise of resonant periods between the two legs in persons with unilateral traumatic transtibial amputation (TTA) at self-selected walking velocity (SSWV), with an aim to better understand the energy minimization mechanisms of walking. It was hypothesized that (1) SSWV was the most energy-efficient walking velocity (MEWV), (2) the stride period at SSWV (Ts) is a compromise between the resonant periods of the normal leg (Tn) and the prosthetic leg (Tp) when they are dissimilar. Eight subjects completed multiple-speed treadmill walking tests (at 53, 67, 80, 93, and 107 m/min) according to three mass conditions (60%, 80%, and 100% of the normal leg below-knee mass) in a random order. Oxygen consumption and stride period were measured, and SSWV was empirically determined. The MEWV, the speed with minimum energy expenditure per distance traveled, was derived from quadratic regression, and its stride period (Tm) was estimated. A theoretical compromise period (Tv) between Tn and Tp was predicted by a virtual single pendulum system based on Huygens' Law. Across different mass conditions, comparisons were made among: Ts, Tm, Tv, Tn, and Tp. Results showed that: (1) Ts was significantly different from Tm; (2) Ts was greater than both Tn and Tp; (3) no significant difference was found between Tm and Tn. Implications for amputee rehabilitation in terms of thigh muscle training and prosthesis development were discussed.

The effects of added prosthetic mass on physiologic responses and stride frequency during multiple speeds of walking in persons with transtibial amputation.

OBJECTIVES: To determine the effect of 3 prosthetic mass conditions on selected physiologic responses during multiple speed treadmill walking in persons with transtibial amputation. DESIGN: A repeated-measures design for 3 prosthetic mass conditions and 5 walking speeds. SETTING: University research laboratory. PARTICIPANTS: Eight ambulatory men with unilateral traumatic transtibial amputation. INTERVENTIONS: The 3 prosthetic mass conditions were 60%, 80%, and 100% of the estimated intact limb below-knee mass. The multiple-speed treadmill walking test (4min at each speed: 54, 67, 80, 94, 107m/min) was performed on an instrumented treadmill according to randomly assigned mass conditions. MAIN OUTCOME MEASURES: Oxygen consumption, gait efficiency, relative exercise intensity (percentage of age-predicted maximal heart rate), and stride frequency. RESULTS: Prosthetic mass did not significantly alter oxygen consumption or gait efficiency (P>.05). From the 60% to the 100% prosthetic mass conditions, relative exercise intensity significantly increased and stride frequency significantly decreased (P<.05). CONCLUSIONS: A heavier prosthesis (up to 100% of estimated intact limb below-knee mass) did not significantly increase the energy costs of walking for the 5 speeds examined. Further study of gait symmetry with the use of a heavier prosthesis is warranted.

Criterion methods of body composition analysis for children and adolescents.

The lack of chemical maturity, subsequent to normal growth and maturation, complicates the assessment of body composition in children. Even though known to overpredict percent body fat (%BF), the use of adult prediction equations is widespread in the pediatric literature. Many sex- and age-specific modified equations have been proposed. This study reports a cross-validation analysis of selected laboratory-based criterion methods in an attempt to identify the most appropriate reference which could be used in future validation studies of the more practical field/clinical testing methods. Subjects were 48 (24 boys and 24 girls) peripubertal children evenly distributed according to stage of maturation. Criterion measurements included body density (Db) by hydrostatic weighing, total body water (TBW) by deuterium oxide dilution, and total body mineral content (TMC) by dual energy x-ray absorptiometry. Five different prediction models were evaluated. Test-retest reliabilty was high (ICC = .970 to .999). Of the prediction models tested, the four-component model was considered the most accurate laboratory-based criterion model since it involves measurement of the primary constituents of fat-free mass. Based on high r2 (≥.942) values, low standard errors of estimate (SEE = 1.8 %BF males, 1.1 %BF females); and low total prediction errors (TE = 1.9 %BF males, 2.0 %BF females), the Lohman age-adjusted prediction equation showed the best agreement with the four component model. If multiple testing facilities are unavailable, the Lohman two-component (Db) model would be the criterion method of choice. © 1993 Wiley-Liss, Inc.