Syndromic Surveillance for Local Outbreaks of Lower-Respiratory Infections: Would It Work?

Background

Although syndromic surveillance is increasingly used to detect unusual illness, there is a debate whether it is useful for detecting local outbreaks. We evaluated whether syndromic surveillance detects local outbreaks of lower-respiratory infections (LRIs) without swamping true signals by false alarms.

Methods and Findings

Using retrospective hospitalization data, we simulated prospective surveillance for LRI-elevations. Between 1999–2006, a total of 290762 LRIs were included by date of hospitalization and patients place of residence (>80% coverage, 16 million population). Two large outbreaks of Legionnaires disease in the Netherlands were used as positive controls to test whether these outbreaks could have been detected as local LRI elevations. We used a space-time permutation scan statistic to detect LRI clusters. We evaluated how many LRI-clusters were detected in 1999–2006 and assessed likely causes for the cluster-signals by looking for significantly higher proportions of specific hospital discharge diagnoses (e.g. Legionnaires disease) and overlap with regional influenza elevations. We also evaluated whether the number of space-time signals can be reduced by restricting the scan statistic in space or time. In 1999–2006 the scan-statistic detected 35 local LRI clusters, representing on average 5 clusters per year. The known Legionnaires'' disease outbreaks in 1999 and 2006 were detected as LRI-clusters, since cluster-signals were generated with an increased proportion of Legionnaires disease patients (p:<0.0001). 21 other clusters coincided with local influenza and/or respiratory syncytial virus activity, and 1 cluster appeared to be a data artifact. For 11 clusters no likely cause was defined, some possibly representing as yet undetected LRI-outbreaks. With restrictions on time and spatial windows the scan statistic still detected the Legionnaires'' disease outbreaks, without loss of timeliness and with less signals generated in time (up to 42% decline).

Conclusions

To our knowledge this is the first study that systematically evaluates the performance of space-time syndromic surveillance with nationwide high coverage data over a longer period. The results show that syndromic surveillance can detect local LRI-outbreaks in a timely manner, independent of laboratory-based outbreak detection. Furthermore, since comparatively few new clusters per year were observed that would prompt investigation, syndromic hospital-surveillance could be a valuable tool for detection of local LRI-outbreaks.     

Egg Recognition and Social Parasitism in Formica Ants

Nests of social insects are an attractive resource in terms of nutrition and shelter and therefore targeted by a variety of pathogens and parasites that harness the resources of a host colony in their own reproductive interests. Colonies of the ants Formica fusca and F. lemani serve as hosts for mound‐building Formica species, the queens of which use host colonies during colony founding. Here, we investigate whether workers of the host species can mitigate the costs imposed on them by invading parasite queens by recognizing and selectively removing eggs laid by these queens. We used behavioural assays, allowing host workers to choose between con‐colonial eggs and eggs laid by the parasite species F. truncorum. We show that workers of both host species discriminate between the two types of eggs in favour of con‐colonial eggs. Moreover, workers of F. fusca rejected more con‐colonial eggs than F. lemani. This higher rate of error in F. fusca may reflect a greater selectivity or a greater difficulty in discriminating between the two egg types. Nevertheless, both host species removed parasite eggs at a similar rate, when these were artificially introduced into the colonies, although some eggs remained after 10 d. In addition, upon receiving parasite eggs, host workers started to lay unfertilized male‐destined eggs within 6 d, thus employing an alternative pathway to gain direct fitness when the resident queen is no longer present and the colony is parasitized.     

Worker reproduction in Formica ants

A potential tragedy of the commons arises in social-insect colonies where workers are fertile if egg-laying workers decrease their contribution to other tasks. We studied worker ovary development and egg laying in relation to kin structure, colony size, and the presence of a queen in nine species (11 populations) of Formica ants. Workers were highly fertile and laid eggs in the presence of a queen in five out of the seven species where egg samples were obtained. Worker fertility correlated neither with colony size nor with kin structure, which suggests that colony-level costs and efficiency of policing precede relatedness as the most important conflict determinant. We conclude that careful quantification of the costs of worker reproduction and policing is essential for inferences about the tragedy of the commons.     

Copepods as environmental indicator in lakes: special focus on changes in the proportion of calanoids along nutrient and pH gradients

Copepods are important contributors to the zooplankton community in lakes. Being “sandwiched” between predators and resources, they are sensitive to changes in the environment. It has been proposed that the proportion of calanoids of total copepod abundance or biomass could be a valuable indicator of eutrophication. We investigated relationships between environmental factors and the abundance, biomass and size of calanoid and cyclopoid copepods as well as their proportions in summer in 68 Danish freshwater lakes (587 lake years) with contrasting nutrient levels and pH. When lake pH was?<?6.0, mean lake depth and trophic state were the most important factors and calanoids completely dominated the copepod community. In shallow lakes with a mean depth?<?2.5 m and with pH?>?6.0, the proportion of calanoids in terms of biomass decreased substantially with increasing phosphorus and chlorophyll a concentrations but stayed around 50% at?>?2.5 m depth irrespective of nutrient level. Time series of the lakes, recovering from eutrophication, confirmed this multi-lake pattern although the trajectory varied from lake to lake. We conclude that the proportion of calanoids in terms of biomass might be a valuable indicator of trophic state in shallow but not deep lakes and only when pH?>?6.

     

Major changes in CO<Subscript>2</Subscript> efflux when shallow lakes shift from a turbid to a clear water state

Lakes can be sources or sinks of carbon, depending on local conditions. Recent studies have shown that the CO₂ efflux increases when lakes recover from eutrophication, mainly as a result of a reduction in phytoplankton biomass, leading to less uptake of CO₂ by producers. We hypothesised that lake restoration by removal of coarse fish (biomanipulation) or invasion of mussels would have a similar effect. We studied 14–22 year time series of five temperate Danish lakes and found profound effects on the calculated CO₂ efflux of major shifts in ecosystem structure. In two lakes, where limited colonisation of submerged macrophytes occurred after biomanipulation or invasion of zebra mussels (Dreissena polymorpha), the efflux increased significantly with decreasing phytoplankton chlorophyll a. In three lakes with major interannual variation in macrophyte abundance, the efflux declined with increasing macrophyte abundance in two of the lakes, while no relation to macrophytes or chlorophyll a was found in the third lake, likely due to high groundwater input to this lake. We conclude that clearing water through invasive mussels or lake restoration by biomanipulation may increase the CO₂ efflux from lakes. However, if submerged macrophytes establish and form dense beds, the CO₂ efflux may decline again.     

Weitere Untersuchungen über die formative Wirkung des Lichtes und mechanischer Reize auf Pflanzen

Zusammenfassung der Ergebnisse Auf das Längenwachstum der Hypokotyle vonSinapis alba wirkt intermittierendes Licht stärker wachstumshemmend (etiolementsverhindernd) als (bei gleicher Reizsumme) kontinuierliches; die Hemmung wird weiterhin mit zunehmendem Zeitabstand zwischen den Teilreizen stärker. Hieraus kann geschlossen werden, daß jeder Teilreiz ein Refraktärstadium von mehreren Minuten Dauer induziert, das erst abgeklungen sein muß, wenn ein zweiter Reiz voll wirksam werden soll.Die formative Wirkung des Lichtes auf das Blatt ist anderer Natur; das zeigen auch ältere Beobachtungen über die unterschiedliche Abhängigkeit von der Lichtqualität.Auch durch mechanische Reize wird das Längenwachstum der Hypokotyle vonSinapis um so mehr gehemmt, je größer der Zeitabstand zwischen den Teilreizen der intermittierenden Reizung ist; auch hier machen sich also Refraktärstadien geltend.Diese Beobachtungen stützen die schon früher gezogene Schlußfolgerung, daß eine Komponente der formativen Wirkung des Lichtes in der Auslösung von Erregungsvorgängen im engeren Sinne besteht, wie sie ähnlich auch durch mechanische Reizung bedingt werden können.Die Beeinflussung der Gewebedifferenzierung in den Internodien vonVicia Faba durch mechanische Reize ist teilweise übereinstimmend mit der durch photische Reizung bedingten, so daß man für einen Teil dieser Beeinflussungen, namentlich für die Ausbildung von Wandverdickungen, vermuten darf, daß sie bei beiden Reizarten gemeinsam durch die Vermittlung jener Erregungsvorgänge entsteht.Mit 6 Textabbildungen.     

Robotic assisted surgery in gynecology: current insights and future perspectives

To focus on the recent adoption, patents, experience, and future of Robotic assisted surgery (RAS) applications in gynecologic surgery, a computer aided and manual search for clinical and systematic reviews, randomized controlled trials, prospective observational studies, retrospective studies and case reports published between 1970 and January of 2011 has been performed. The use of RAS in gynecologic patients includes hysterectomy, myomectomy, tubal reanastomoses, radical hysterectomy, lymph node dissection, and sacrocolpopexies. Although individual studies vary, gynecological RAS is often associated with longer operating room time but similar clinical outcomes, decreased blood loss, and shorter hospital stay. RAS procedures on women have, however, their own limitations: the patented equipment is very large, bulky, and expensive, the staff must be trained specifically on draping and docking the instruments, the lack of surgical haptic feedback, a limited vaginal access, a limited specific instrumentation, and the need for larger port incisions requiring fascial closure. The RAS significantly facilitates gynecologic surgery, even if well-designed, prospective studies are needed to fully assess the value of this equipments in particular studies with well-defined clinical and long-term outcomes, including complications, cost, pain, return to normal activity, and quality of life. The future of robotic surgery in gynecology may be bright, but currently, caution is advisable and clinically meaningful long-term outcomes are needed. These recent patents, however, has exciting potential for future applications, especially in long-distance telesurgery and might change the paradigm of gynecologic surgery in the future.     

Range contraction and increasing isolation of a polar bear subpopulation in an era of sea‐ice loss

Climate change is expected to result in range shifts and habitat fragmentation for many species. In the Arctic, loss of sea ice will reduce barriers to dispersal or eliminate movement corridors, resulting in increased connectivity or geographic isolation with sweeping implications for conservation. We used satellite telemetry, data from individually marked animals (research and harvest), and microsatellite genetic data to examine changes in geographic range, emigration, and interpopulation connectivity of the Baffin Bay (BB) polar bear (Ursus maritimus) subpopulation over a 25‐year period of sea‐ice loss. Satellite telemetry collected from n = 43 (1991–1995) and 38 (2009–2015) adult females revealed a significant contraction in subpopulation range size (95% bivariate normal kernel range) in most months and seasons, with the most marked reduction being a 70% decline in summer from 716,000 km² (SE 58,000) to 211,000 km² (SE 23,000) (p < .001). Between the 1990s and 2000s, there was a significant shift northward during the on‐ice seasons (2.6^° shift in winter median latitude, 1.1^° shift in spring median latitude) and a significant range contraction in the ice‐free summers. Bears in the 2000s were less likely to leave BB, with significant reductions in the numbers of bears moving into Davis Strait (DS) in winter and Lancaster Sound (LS) in summer. Harvest recoveries suggested both short and long‐term fidelity to BB remained high over both periods (83–99% of marked bears remained in BB). Genetic analyses using eight polymorphic microsatellites confirmed a previously documented differentiation between BB, DS, and LS; yet weakly differentiated BB from Kane Basin (KB) for the first time. Our results provide the first multiple lines of evidence for an increasingly geographically and functionally isolated subpopulation of polar bears in the context of long‐term sea‐ice loss. This may be indicative of future patterns for other polar bear subpopulations under climate change.     

Excess mortality rate during adulthood among Danish adoptees

Background and objective

Adoption studies have been used to disentangle the influence of genes from shared familial environment on various traits and disease risks. However, both the factors leading to adoption and living as an adoptee may bias the studies with regard to the relative influence of genes and environment compared to the general population. The aim was to investigate whether the cohort of domestic adoptees used for these studies in Denmark is similar to the general population with respect to all-cause mortality and cause-specific mortality rates.

Methods

13,111 adoptees born in Denmark in 1917, or later, and adopted in 1924 to 1947 were compared to all Danes from the same birth cohorts using standardized mortality ratios (SMR). The 12,729 adoptees alive in 1970 were similarly compared to all Danes using SMR as well as cause-specific SMR.

Results

The excess in all-cause mortality before age 65 years in adoptees was estimated to be 1.30 (95% CI 1.26–1.35). Significant excess mortality before age 65 years was also observed for infections, vascular deaths, cancer, alcohol-related deaths and suicide. Analyses including deaths after age 65 generally showed slightly less excess in mortality, but the excess was significant for all-cause mortality, cancer, alcohol-related deaths and suicides.

Conclusion

Adoptees have an increased all-cause mortality compared to the general population. All major specific causes of death contributed, and the highest excess is seen for alcohol-related deaths.     

Plasmodium vivax dihydrofolate reductase as a target of sulpha drugs

Sulpha drugs act as competitive inhibitors of p-amino benzoic acid, an intermediate in the de novo folate pathway. Dihydropteroate synthase condenses sulpha drugs into sulpha-dihydropteroate (sulpha-DHP), which competes with dihydrofolate, the dihydrofolate reductase (DHFR) substrate. This designates DHFR as a possible target of sulpha-DHP. We suggest here that Plasmodium vivax DHFR is indeed the in vivo target of sulpha drugs. The wild-type DHFR expressed in Saccharomyces cerevisiae leads to cell growth inhibition, while sensitivity to the drug is exacerbated in the mutants. Contrary to what is observed with sulphanilamide, methotrexate is less effective on P. vivax-DHFR mutants than on wild-type mutant.