Low Yield of Clinically Significant Injury With Head-To-Pelvis Computed Tomography in Blunt Trauma Evaluation.

BACKGROUND: Many trauma centers have adopted routine head-to-pelvis computed tomography (CT) imaging for the evaluation of adults with blunt trauma. OBJECTIVE: We sought to determine the yields of detecting clinically significant injuries (CSIs) with CT in >1 anatomic region. METHODS: We conducted this observational cohort study of all trauma activation patients >14 years of age who received CT imaging during blunt trauma evaluation at a Level 1 trauma center from April to October 2014. Expert panels determined the clinical significance of head, neck, chest, abdomen, and pelvis injuries seen on CT. We calculated yields of CSI, defined as the number of patients with CSI divided by the total number of patients who underwent CT imaging. The 3 specified anatomic regions considered were head/neck, chest, and abdomen/pelvis. RESULTS: The median age of 1236 patients who had CT was 48 years; 69% were male; 51.2% were admitted; and hospital mortality was 4.4%. Yields of CSI with 95% confidence intervals (CIs) were: head/neck region injury 11.3% (9.6-13.3%); chest region injury only 7.9% (6.0-10.4%); abdomen/pelvis region injury only 5.1% (3.7-7.0%); both head/neck and chest CSI 2.8% (1.7-4.5%); both head/neck and abdomen/pelvis CSI 1.6% (0.9-2.9%); and both chest and abdomen/pelvis CSI 1.1% (0.5-2.4%). The yield of CSI in all 3 anatomic regions with head-to-pelvis CT was 0.6% (0.2-1.7%), and 76.7% (68.8-83.1%) of CSIs occurred in isolation. CONCLUSIONS: During multiple anatomic region CT imagng for adult blunt trauma evaluation, the yield for CSI in >1 region is low. In low-risk populations, selective CT imaging of anatomic regions (instead of reflexive head-to-pelvis CT imaging) may be more appropriate.

Development of a low-dose fipronil deer feed: Bait-screening and range-finding to determine the optimal formulation to control blacklegged ticks (Ixodes scapularis) feeding on white-tailed deer (Odocoileus virginianus).

Lyme disease is the most prevalent vector-borne disease in the U.S., and acaricidal feeds administered to white-tailed deer (Odocoileus virginianus) have potential to disrupt blood feeding by the blacklegged tick, Ixodes scapularis. Two studies were conducted with the aim of determining an ideal formulation to deliver oral acaricides to white-tailed deer and finding the lowest fipronil dose level to effectively control I. scapularis. During formulation screening, various commercial attractants (baits) were presented to deer in large paddocks under semi-field conditions and motion-sensitive cameras were used to monitor consumption by deer and non-target species. During dose range-finding, deer were housed individually and presented a fipronil feed at one of five dose levels for 48 h (two deer untreated). At 24 h post-exposure, the deer were anesthetized, blood was drawn, and deer were manually infested with 20 I. scapularis mating pairs in feeding capsules. Tick mortality was monitored up to nine days post-attachment. Results of formulation screening indicated that loose/granular formulations were substantially more palatable to deer, relative to block formulations, and would be more effective under field conditions. Dose range-finding concluded fipronil feeds with doses of 25 ppm and higher would eliminate 100% of I. scapularis parasitizing deer. Additionally, 10 ppm fipronil feed controlled a considerable proportion of ticks, and results suggested 100% ticks could be eliminated if fipronil sulfone was present in plasma at ≥25.1 ppb. These results were paramount in developing a low dose fipronil deer feed for tick control and should provide valuable insights prior to execution of future field trials.

Development of a low-dose fipronil deer feed: evaluation of efficacy against two medically important tick species parasitizing white-tailed deer (Odocoileus virginianus) under pen conditions.

BACKGROUND: Odocoileus virginianus (the white-tailed deer) is a key reproductive host for medically important tick species, including Ixodes scapularis and Amblyomma americanum. Orally administering a systemic acaricide to white-tailed deer has the potential to reduce tick reproduction, abundance and pathogen-infected tick bites. Prior studies have demonstrated considerable efficacy of a low-dose fipronil mouse bait in controlling larval I. scapularis parasitizing the pathogen reservoir, Peromyscus leucopus. No prior studies have evaluated the efficacy of a fipronil product in controlling ticks parasitizing white-tailed deer. METHODS: A pen study was conducted to evaluate the efficacy of a fipronil deer feed in controlling I. scapularis and A. americanum adult ticks. Individually housed deer (n = 24) were exposed to deer feed containing 0.0025% fipronil (fipronil deer feed) for 48 h and 120 h, and a control group of deer were exposed to an untreated placebo. On post-exposure day 7 and day 21, all deer were parasitized with 20 mating pairs of feeding capsule-enclosed I. scapularis and A. americanum. Post-attachment, engorgement and mortality of ticks were recorded. The concentrations of fipronil in plasma, feces and tissues from euthanized deer were estimated using liquid chromatography-mass spectrometry. RESULTS: The fipronil deer feed efficaciously controlled ticks parasitizing pen-reared white-tailed deer. Efficacy in reducing survivorship of blood-feeding female I. scapularis exceeded 90% in all instances except for when ticks parasitized 48-h treated deer at day 21 post-exposure (47.2%). Efficacy in reducing survivorship of A. americanum females exceeded 80% in all instances. In the 120-h exposure group there was 100% tick mortality at day 7 post-exposure for both tick species. A significant correlation was observed between reductions in tick survivorship and concentrations of fipronil sulfone in plasma. The results of tissue analysis suggest that a withdrawal period may be needed to allow for fipronil degradation prior to hunting season. CONCLUSIONS: The results provide proof-of-concept for the use of a fipronil-based oral acaricide in controlling two medically important tick species infesting a key reproductive host. A field trial is necessary to confirm the efficacy and toxicology of the product in wild deer populations. Fipronil deer feed may provide a means of controlling multiple tick species parasitizing wild ruminants to be integrated into tick management programs.

Emergence of complex haplotypes from microevolutionary variation in sequence and structure of Colias phosphoglucose isomerase.

A molecular evolutionary explanation of natural genetic variation requires analysis of specific variants' evolutionary dynamics. To pursue this for phosphoglucose isomerase (PGI) of Colias butterflies, whose polymorphism is maintained by strong natural selection, we assembled a large data set of wild haplotypes, highly variable at the amino acid and DNA levels. The most common electrophoretic, i.e., charge macrostate, allele class, 3, is conserved in its pattern of charged amino acid residues. The next most common macrostate, 4, has multiple patterns of charge, i.e., microstates, while less common (1, 2, 5, 6) macrostates are very diverse. Macrostate 4 shows significant linkage disequilibrium (LD) among its variants, especially for two groups of five haplotypes each. We find extensive intragenic recombination among all haplotypes except the two high-LD groups of macrostate 4, which display none. Phyletic relations among haplotypes are largely reticulate, again except for the high-LD groups of macrostate 4, which form clades with strong bootstrap support. Charge-changing and linked charge-neutral amino acid variants occur in diverse parts of PGI's sequence. Homology-based modeling of PGI's structure shows that these regions are related spatially in ways suggesting functional interaction. The high-LD groups of macrostate 4 display parallel amino acid variation in these regions. This pattern of haplotype clades with high LD among multiple varying sites, emerging from chaotically recombining variation, may be a "signature" of refinement of complex adaptive sequences by recombination and selection. It should be tested further in this study system and others as a possibly general feature of the evolution of living complexity.

Blunt Trauma Abdominal and Pelvic Computed Tomography Has Low Yield for Injuries in More Than One Anatomic Region.

INTRODUCTION: Most trauma centers order abdominal and pelvic computed tomography (CT) as an automatically paired CT for adult blunt trauma evaluation. However, excessive CT utilization adds risks of excessive exposure to ionizing radiation, the need to work up incidental findings (leading to unnecessary and invasive tests), and greater costs. Examining a cohort of adult blunt trauma patients that received paired abdominal and pelvic (A/P) CT, we sought to determine the diagnostic yield of clinically significant injuries (CSI) in the following: 1) the abdomen alone; 2) the pelvis alone; 3) the lumbosacral spine alone; and 4) more than one of these anatomic regions concomitantly. METHODS: In this retrospective study, we reviewed the imaging and hospital course of a consecutive sample of blunt trauma activation patients older than 14 years of age who received paired A/P CT during their blunt trauma assessments at an urban Level I trauma center from April through October 2014. Categorization of CSI was determined according to an a priori, expert panel-derived classification scheme. RESULTS: The median age of the 689 patients who had A/P CT was 48 years old; 68.1% were male; 64.0% were admitted, and hospital mortality was 3.6%. CSI yields were as follows: abdomen 2.2% (95% confidence interval [CI] [1.3-3.6%]); pelvis 2.9% (95% CI [1.9-4.4%]); lumbosacral spine 0.6% (95% CI [0.2-1.5%]); both abdomen and pelvis 0.3% (95% CI [0.1-1.1%]); both the abdomen and lumbosacral spine 0.6% (0.2-1.5%); both the pelvis and lumbosacral spine 0.1% (0.0-0.8%); all three regions - abdomen, pelvis and lumbosacral spine - 0.1% (0.0-0.8%). CONCLUSION: Automatic pairing of A/P CT has very low diagnostic yield for CSI in both the abdomen and pelvis. These data suggest a role for selective CT imaging protocols that image these regions individually instead of automatically as a pair.