Using age-stratified incidence data to examine the transmission consequences of pertussis vaccination.

Pertussis is a highly infectious respiratory disease that has been on the rise in many countries worldwide over the past several years. The drivers of this increase in pertussis incidence remain hotly debated, with a central and long-standing hypothesis that questions the ability of vaccines to eliminate pertussis transmission rather than simply modulate the severity of disease. In this paper, we present age-structured case notification data from all provinces of Thailand between 1981 and 2014, a period during which vaccine uptake rose substantially, permitting an evaluation of the transmission impacts of vaccination. Our analyses demonstrate decreases in incidence across all ages with increased vaccine uptake - an observation that is at odds with pertussis case notification data in a number of other countries. To explore whether these observations are consistent with a rise in herd immunity and a reduction in bacterial transmission, we analyze an age-structured model that incorporates contrasting hypotheses concerning the immunological and transmission consequences of vaccines. Our results lead us to conclude that the most parsimonious explanation for the combined reduction in incidence and the shift to older age groups in the Thailand data is vaccine-induced herd immunity.

Predicting bat colony survival under controls targeting multiple transmission routes of white-nose syndrome.

White-nose syndrome (WNS) is a lethal infection of bats caused by the psychrophilic fungus Pseudogymnoascus destructans (Pd). Since the first cases of WNS were documented in 2006, it is estimated that as many as 5.5million bats have succumbed in the United States-one of the fastest mammalian die-offs due to disease ever observed, and the first known sustained epizootic of bats. WNS is contagious between bats, and mounting evidence suggests that a persistent environmental reservoir of Pd plays a significant role in transmission as well. It is unclear, however, the relative contributions of bat-to-bat and environment-to-bat transmission to disease propagation within a colony. We analyze a mathematical model to investigate the consequences of both avenues of transmission on colony survival in addition to the efficacy of disease control strategies. Our model shows that selection of the most effective control strategies is highly dependent on the primary route of WNS transmission. Under all scenarios, however, generalized culling is ineffective and while targeted culling of infected bats may be effective under idealized conditions, it primarily has negative consequences. Thus, understanding the significance of environment-to-bat transmission is paramount to designing effective management plans.

The role of interconnectivity in control of an Ebola epidemic.

Several West African countries - Liberia, Sierra Leone and Guinea - experienced significant morbidity and mortality during the largest Ebola epidemic to date, from late 2013 through 2015. The extent of the epidemic was fueled by outbreaks in large urban population centers as well as movement of the pathogen between populations. During the epidemic there was no known vaccine or drug, so effective disease control required coordinated efforts that include both standard medical and community practices such as hospitalization, quarantine and safe burials. Due to the high connectivity of the region, control of the epidemic not only depended on internal strategies but also was impacted by neighboring countries. In this paper, we use a deterministic framework to examine the role of movement between two populations in the overall success of practices designed to minimize the extent of Ebola epidemics. We find that it is possible for even small amounts of intermixing between populations to positively impact the control of an epidemic on a more global scale.

The Impact of a Home-Based Computerized Cognitive Training Intervention on Fall Risk Measure Performance in Community Dwelling Older Adults, a Pilot Study.

OBJECTIVES: Cognitive intervention studies have reported improvements in various domains of cognition as well as a transfer effect of improved function post training. Despite the availability of web based cognitive training programs, most intervention studies have been performed under the supervision of researchers. Therefore, the purpose of this study was to first, examine the feasibility of a six week home based computerized cognitive training (CCT) program in a group of community dwelling older adults and, second, to determine if a CCT program which focused on set shifting, attention, and visual spatial ability impacted fall risk measure performance. DESIGN: This pilot study used a pretest/posttest experimental design with randomization by testing site to an intervention or control group. PARTICIPANTS: Community dwelling older adults (mean age = 74.6 years) participated in either the control (N=25) or the intervention group (N=19). INTERVENTION: Intervention group subjects participated in 6 weeks of home based CCT 3x/week for an average of 23 minutes/session, using an online CCT program. MEASUREMENTS: Comparisons of mean scores on three measures of physical function (usual gait speed, five times sit to stand, timed up and go) were completed at baseline and week 7. RESULTS: Following the completion of an average of 18 sessions of CCT at home with good adherence (86%) and retention (92%) rates, a statistically significant difference in gait speed was found between groups with an average improvement of 0.14 m/s in the intervention group. CONCLUSION: A home based CCT program is a feasible approach to targeting cognitive impairments known to influence fall risk and changes in gait in older adults.

Effects of Computerized Cognitive Training on Gait Speed in Community Dwelling Older Adults, A Pilot Study.

BACKGROUND: In older adults declines in gait speed have been identified as predictors of functional decline and have been found in those with cognitive dysfunction. Cognitive training interventions that emphasize addressing executive function (EF) have resulted in a transfer effect from training cognitive processes into improved function. However research examining the effects of an EF specific computerized cognitive training (CCT) program on gait speed (GS) is limited. OBJECTIVES: To compare the effects of a six week EF specific CCT program on GS in community dwelling older adults using a pretest/posttest experimental design with subgroup comparisons based on a cutoff GS of 1.0m/s. SETTING: Home based. PARTICIPANTS: Forty independent living older adults (>65 years) without diagnosed cognitive impairment participated in either the intervention or control groups. INTERVENTION: A six week long progressively challenging EF focused CCT program was performed at home. MEASUREMENTS: Demographic variables, cognitive function (Trail-Making Test Part B) and GS were measured at baseline at week 7. Between group comparisons were completed for the whole sample initially with subgroup comparisons performed based on participants' initial GS (Slow walkers: GS<1.0m/s; Fast Walkers: GS>1.0m/s). RESULTS: No differences in GS were found for the whole population, but subgroup analyses restricted to slow walkers demonstrated a statistically significant improvement in GS after 6 weeks of CCT (µ =0.33 m/s, p = 0.03). Other outcomes measures were not statistically different at posttest. CONCLUSIONS: Older adults who walk at speeds <1.0m/s may benefit from a progressively challenging CCT program when self-administered in the home.

A decision framework for prioritizing multiple management actions for threatened marine megafauna.

Resources for conserving biodiversity are invariably insufficient. This situation creates the need for transparent, systematic frameworks to help stakeholders prioritize the allocation of resources across multiple management actions. We developed a novel framework that explicitly prioritizes actions to minimize the impacts of several threats across a species' range. The framework uses a budget constraint and maximizes conservation outcomes from a set of management actions, accounting for the likelihood of the action being successfully applied and accepted by local and Indigenous communities. This approach is novel in that it integrates local knowledge and expert opinion with optimization software, thereby minimizing assumptions about likelihood of success of actions and their effectiveness. To test the framework, we used the eastern Gulf of Carpentaria and Torres Strait population of the flatback turtle, Natator depressus, as a case study. This approach allowed the framework to be applied in a data-poor context, a situation common in conservation planning. The framework identified the best set of actions to maximize the conservation of flatback eggs for scenarios with different budgets and management parameters and allowed comparisons between optimized and preselected scenarios. Optimized scenarios considered all implementable actions to explore how to best allocate resources with a specified budget and focus. Preselected scenarios were used to evaluate current allocations of funds and/or potential budget allocations suggested by different stakeholders. Scenarios that used a combination of aerial and ground strategies to reduce predation of eggs performed better than scenarios that focused only on reducing harvest of eggs. The performances of optimized and preselected scenarios were generally similar among scenarios that targeted similar threats. However, the cost-effectiveness of optimized scenarios was usually higher than that of preselected scenarios, demonstrating the value of conducting a systematic optimization approach. Our method provides a foundation for more effective conservation investments and guidance to prioritize actions within recovery plans while considering the sociopolitical and cultural context of decisions. The framework can be adapted easily to a wide range of species, geographical scales, and life stages.

(2S,4E)-2-Hydroxy-4-octen-3-one, a Male-Produced Attractant Pheromone of the Cerambycid Beetle Tylonotus bimaculatus.

We report the identification of a novel pheromone structure from males of the cerambycid beetle Tylonotus bimaculatus Haldeman (Cerambycinae: Hesperophanini), a species native to eastern North America. Volatiles collected from adult males contained (2S,4E)-2-hydroxyoct-4-en-3-one (71%), (3R,4E)-3-hydroxyoct-4-en-2-one (15%), (E)-4-octen-2,3-dione (13%), and 2,3-octanedione (1.5%). Four independent field bioassays with synthetic compounds confirmed that adults of both sexes were attracted by the racemate of the major component, (E)-2-hydroxyoct-4-en-3-one. No other cerambycid species were attracted in significant numbers. Attraction of both sexes is consistent with the male-produced pheromones of many other species in the subfamily Cerambycinae, but T. bimaculatus is unusual in having a pheromone chemistry that is so far unique among species in that subfamily.

The population ecology of infectious diseases: pertussis in Thailand as a case study.

Many of the fundamental concepts in studying infectious diseases are rooted in population ecology. We describe the importance of population ecology in exploring central issues in infectious disease research including identifying the drivers and dynamics of host-pathogen interactions and pathogen persistence, and evaluating the success of public health policies. The use of ecological concepts in infectious disease research is demonstrated with simple theoretical examples in addition to an analysis of case notification data of pertussis, a childhood respiratory disease, in Thailand as a case study. We stress that further integration of these fields will have significant impacts in infectious diseases research.

Variance in Bacillus anthracis virulence assessed through Bayesian hierarchical dose-response modelling.

AIMS: To develop a predictive dose-response model for describing the survival of animals exposed to Bacillus anthracis to support risk management options. METHODS AND RESULTS: Dose-response curves were generated from a large dose-mortality data set (>11,000 data points) consisting of guinea pigs exposed via the inhalation route to 76 different product preparations of B. anthracis. Because of the predictive nature of the Bayesian hierarchical approach (BHA), this method was used. The utility of this method in planning for a variety of scenarios from best case to worst case was demonstrated. CONCLUSIONS: A wide range of expected virulence was observed across products. Median estimates of virulence match well with previously published statistical estimates, but upper bound values of virulence are much greater than previous statistical estimates. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first meta-analysis in open literature to estimate the dose-response relationship for B. anthracis from a very large data set, generally a rare occurrence for highly infectious pathogens. The results are also the first to suggest the extent of variability, which is contributed by product preparation and/or dissemination methods, information needed for health-based risk management decisions in response to a deliberate release. A set of possible benchmark values produced through this analysis can be tied to the risk tolerance of the decision-maker or available intelligence. Further, the substantial size of the data set led to the ability to assess the appropriateness of the assumed distributional form of the prior, a common limitation in Bayesian analysis.

Brain death and the cervical spinal cord: a confounding factor for the clinical examination.

STUDY DESIGN: This study is a systematic review. OBJECTIVES: Brain death (BD) is a clinical diagnosis, made by documenting absent brainstem functions, including unresponsive coma and apnea. Cervical spinal cord dysfunction would confound clinical diagnosis of BD. Our objective was to determine whether cervical spinal cord dysfunction is common in BD. METHODS: A case of BD showing cervical cord compression on magnetic resonance imaging prompted a literature review from 1965 to 2008 for any reports of cervical spinal cord injury associated with brain herniation or BD. RESULTS: A total of 12 cases of brain herniation in meningitis occurred shortly after a lumbar puncture with acute respiratory arrest and quadriplegia. In total, nine cases of acute brain herniation from various non-meningitis causes resulted in acute quadriplegia. The cases suggest that direct compression of the cervical spinal cord, or the anterior spinal arteries during cerebellar tonsillar herniation cause ischemic injury to the cord. No case series of brain herniation specifically mentioned spinal cord injury, but many survivors had severe disability including spastic limbs. Only two pathological series of BD examined the spinal cord; 56-100% of cases had upper cervical spinal cord damage, suggesting infarction from direct compression of the cord or its arterial blood supply. CONCLUSIONS: Upper cervical spinal cord injury may be common after brain herniation. Cervical spinal cord injury must either be ruled out before clinical testing for BD, or an ancillary test to document lack of brainstem blood flow is required in all cases of suspected BD. BD may not be a purely clinical diagnosis.

Classifying life-style types of phytoseiid mites: diagnostic traits.

Several traits are useful for identifying life-style types of predaceous phytoseiid mites when either 2 (diet generalist-specialist) or 4 (specialist I and II-generalist III and IV) type models [McMurtry J.A. and Croft B.A. 1997. Annu. Rev. Entomol. 42: 291-321] are considered. Traits useful for both models are developmental time and oviposition rates when feeding on several food types. Discriminating for the 2-types model are dorsal shield setae lengths, and intra- and inter-specific predation. Another trait useful for both models is feeding preferences of adult female phytoseiids on eggs versus larvae of Tetranychus urticae Koch. In this paper, we review established and other traits that need more study such as mouthpart types, other morphological features, spider mite webbing effects, distributions relative to prey-foods, plant-host relationships including domatia and sap feeding, density-dependent responses to prey and predator-prey ratios required for biological control. Uses of life-style data in biological control decision-making are discussed.

Evaluation of prey-stage preference as an indicator of life-style type in phytoseiid mites.

Discriminant analysis (DA) models were developed and applied to examine the use of prey-stage preference (Tetranychus urticae Koch egg versus larval prey) in the classification of phytoseiid mites into life-style types. Prey-stage preferences and developmental times when preying on T. urticae, and relative ovipositional rates on six food categories were determined for four phytoseiid species occurring on apple in central and eastern Oregon, USA: Galendromus flumenis (Chant), Galendromus occidentalis (Nesbitt), Metaseiulus citri (Garman and McGregor) and Typhlodromus caudiglans Schuster. In terms of all three aspects studied, the phytoseiid species showed a consistent polarization of G. occidentalis < or = G. flumenis < or = T. caudiglans < M. citri. Specifically, G. occidentalis ('The Dalles' strain) had a significant preference for eggs, G. flumenis had no preference, and T. caudiglans and M. citri had significant preferences for larvae; G. occidentalis had the shortest developmental time, followed by G. flumenis and T. caudiglans, while M. citri had the longest developmental time; and diet breadth was most narrow for G. occidentalis and progressively broader from G. flumenis, T. caudiglans through M. citri, which was able to sustain oviposition on the broadest range of prey and pollens. Species were classified somewhat differently depending on which traits were considered in a given DA. Prey-stage preference was not included as an indicator in the parsimonious DA model when all species and all traits were considered, but in general this trait performed well as an indicator alone (single-trait DA) and somewhat improved the classifications of multitrait discriminant analyses.

Jerking in predaceous mites (Acari: Phytoseiidae) with emphasis on larvae.

Jerking, a behavior involving a pronounced and often repeated lunging of the body, was studied in larvae among seven species of phytoseiid mites, Euseius finlandicus, Galendromus occidentalis, Neoseiulus californicus, Neoseulus fallacis, Phytoseiulus macropilis, Phytoseiulus persimilis and Typhlodromus pyri, and in the nymphal stages of N. fallacis. This behavior was observed in larvae of six of the seven species and in all active immature stages of N. fallacis. Jerking was usually triggered by direct contact with a con- or heterospecific mite, although jerking occurred occasionally without direct contact in N. fallacis larvae. The larval jerking tendency (the mean fraction of contacts resulting in jerking) of a species was significantly correlated with a tendency to congregate with conspecifics. Congregated larvae often probed their immediate area and each other with the front legs, repeatedly jerking in response to contact with neighboring larvae. Species with larvae having higher jerking tendencies also jerked more repeatedly per jerking event. Among species, there was no consistent relationship between jerking tendency and larval age. Larvae of N. fallacis had a higher tendency to jerk than protonymphs and deutonymphs, and they had both the highest jerking and congregating tendencies among larvae of all species studied. An individual was more likely to jerk when approached by another mite than when it initiated contact, and when observed in N. fallacis larvae that initiated contact, jerking was sometimes aggressive. Jerking N. fallacis larvae experienced fewer and shorter periods of probing by the mouthparts and fewer attacks from cannibalistic adult females than anesthetized larvae that were unable to jerk.

Long-term follow-up of treated dental phobics.

Behavioural treatment programmes have been shown repeatedly to be effective in alleviating dental anxiety but few studies have provided long-term follow-ups. In this study, dentally anxious Ss who had completed a 4-session behavioural group programme were followed up for periods between 1 and 4 years after successful completion of treatment. It was hypothesized that dental visit satisfaction would be associated with regular dental attendance. 88% of Ss contacted agreed to cooperate; of these, 70% were still maintaining regular check-ups. There were no differences between regular and irregular attenders in terms of age, gender, education, marital status, degree of pre-treatment avoidance or time elapsed since completion of the programme. However, Ss who did not see their dentists regularly were more likely to have shown higher levels of anxiety immediately after completing the programme, less concordance between the subjective and overt behavioural aspects of anxiety and to have experienced more invasive than non-invasive procedures than the others. It was argued that dentally anxious individuals are not a homogeneous group and that a better understanding of their individual differences would lead to the development of more efficacious treatment procedures.

Surgical prophylaxis for pulmonary embolism.

The trauma patient population is at special risk for fatal pulmonary embolism. We experienced 11 fatalities in one 12-month period. Specific risk factors for both deep venous thrombosis and pulmonary embolism can be identified among trauma patients. The latter usually cannot be offered prophylactic anticoagulation, and the nature of their injuries (e.g., long bone fractures) makes not only bedside surveillance difficult but also precludes use of pneumatic compression, etc. We have developed a protocol for prophylactic inferior vena caval filtration for our trauma patients deemed at particular risk for pulmonary embolism. Since 1986 we have inserted 205 Greenfield filters in 201 patients. Two hundred were inserted prophylactically. There was no mortality, and morbidity was minimal. No patient with a Greenfield filter sustained a fatal pulmonary embolism during this period. Four patients died from pulmonary embolism before vena caval filters could be inserted. We believe that the trauma patient, at risk for pulmonary embolism, should be offered a Greenfield filter prophylactically as soon after hospitalization as logistically possible.

The role of laparoscopy in abdominal trauma.

Thirty-nine hemodynamically stable trauma patients were evaluated prospectively by laparoscopy before planned celiotomy. Laparoscopy was performed using a forward-viewing laparoscope connected to two high-resolution video monitors. The mechanism of injury was blunt trauma in eight, stab wounds (SWs) in 16, and gunshot wounds (GSWs) in 15. Laparoscopy correctly identified the presence of an intraperitoneal injury in 26 patients. Six other patients had retroperitoneal injuries, five of which were seen on laparoscopy. The remaining seven patients had no demonstrable intraperitoneal or retroperitoneal injuries, did not undergo celiotomy, and were observed without morbidity. In comparison with findings at surgery, laparoscopy identified injuries to the liver in eight of ten, to the diaphragm in three of three, to the colon in two of three, to the stomach in three of three, to the kidney in one of one, to the spleen in none of three, and to the small bowel in none of four patients. Visualization of the spleen was achieved in only one patient. The extent of the hemoperitoneum was underestimated from the laparoscopic examination in all nine patients with greater than 750 mL of peritoneal blood, four of whom had undetected active bleeding. Laparoscopy was performed easily in all patients and there were no complications associated with its use. In conclusion, the absence of an intra-abdominal injury was correctly identified with laparoscopy in 11 patients and laparoscopy may decrease the need for celiotomy in selected patients. However, the inability to "run the small bowel," visualize the spleen, and evaluate hemorrhage limits the utility of laparoscopy in determining which patients with laparoscopically visualized injuries will require celiotomy.

Sterilisation of the intellectually disabled: the need for legislative reform.

This article examines the recent decision of the Full Court of the Family Court in Re Marion dealing with the question of sterilisation of intellectually disabled minors and in particular, the question of whether a parent or guardian can lawfully consent to a sterilisation operation upon an intellectually disabled minor or whether court approval is required before such an operation can lawfully be performed. The article goes on to critically examine legislation in force in various Australian jurisdictions concerning involuntary sterilisations and substituted consent as well as legislative reforms that have been proposed in this area.