Temporal Patterns Of Occurrence Research Articles

Daily stream samples reveal highly complex pesticide occurrence and potential toxicity to aquatic life.

Transient, acutely toxic concentrations of pesticides in streams can go undetected by fixed-interval sampling programs. Here we compare temporal patterns in occurrence of current-use pesticides in daily composite samples to those in weekly composite and weekly discrete samples of surface water from 14 small stream sites. Samples were collected over 10-14weeks at 7 stream sites in each of the Midwestern and Southeastern United States. Samples were analyzed for over 200 pesticides and degradates by direct aqueous injection liquid chromatography with tandem mass spectrometry. Nearly 2 and 3 times as many unique pesticides were detected in daily samples as in weekly composite and weekly discrete samples, respectively. Based on exceedances of acute-invertebrate benchmarks (AIB) and(or) a Pesticide Toxicity Index (PTI) >1, potential acute-invertebrate toxicity was predicted at 11 of 14 sites from the results for daily composite samples, but was predicted for only 3 sites from weekly composites and for no sites from weekly discrete samples. Insecticides were responsible for most of the potential invertebrate toxicity, occurred transiently, and frequently were missed by the weekly discrete and composite samples. The number of days with benthic-invertebrate PTI ≥0.1 in daily composite samples was inversely related to Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness at the sites. The results of the study indicate that short-term, potentially toxic peaks in pesticides frequently are missed by weekly discrete sampling, and that such peaks may contribute to degradation of invertebrate community condition in small streams. Weekly composite samples underestimated maximum concentrations and potential acute-invertebrate toxicity, but to a lesser degree than weekly discrete samples, and provided a reasonable approximation of the 90th percentile total concentrations of herbicides, insecticides, and fungicides, suggesting that weekly composite sampling may be a compromise between assessment needs and cost.

Fire dynamics in Mato Grosso State, Brazil: the relative roles of gross primary productivity

ABSTRACTThe fires and biomass burning are responsible for affect ecosystem processes in a wide range of biomes at regional and global scales. In Brazil, the state of Mato Grosso is one of the most affected by the occurrence of forest fires. Thus, this study aims to quantify the long-term changes in the temporal and spatial patterns of fire occurrence and their effect on gross primary productivity (GPP) in the state of Mato Grosso, Brazil, considering the biomes that compose it. The images used in the study were acquired by satellite Terra and Aqua combined in the product MCD64A1.006, a monthly resolution of 500m by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, during the period from 01/10/2000 to 12/31/2018. The MOD17A2 product derived from the MODIS sensor provides the accumulated value of GPP. The points without the presence of burning presented higher values of GPP for all studied biomes. In some points with the presence of burning the GPP even decreased by 44.20%, 30.04% and 55.78% for Amazonia, Cerrado, and Pantanal, respectively. According to the results presented here, it is concluded that the burnings negatively impact gross primary production in the biomes of the state of Mato Grosso, Brazil and the dynamics of the burns do not keep up with the intensity of drought years. The use of cluster analysis techniques, such as principal component analysis (PCA), is an alternative to bigdata analysis when the objective is to evaluate the presence of forest burning in more than one biome.

Multidimensional analysis of temporal and layered microclimatic behavior of subtropical climber green walls in summer

Existing studies emphasizing the magnitude of green-wall thermal benefits paid little attention to temporal microclimatic behavior. To bridge the knowledge gap, we employed high-precision sensors to monitor the microclimate of two wirerope-type climber green walls and adjacent control bare walls in humid-subtropical Hong Kong. Sample days were systematically selected to represent the results on sunny, cloudy and rainy weather in summer. This study aimed at: (1) evaluating the magnitude and daily temporal occurrence of maximum temperature, cooling and insolation at different positions of the layered green walls, and (2) analyzing temporal occurrence patterns of maximum values of microclimatic variables. The results demonstrated the paramount importance of insolation on green-wall microclimate. Varied solar inputs under different weather brought a sequence in maximum insolation, temperature and cooling: sunny > cloudy > rainy. Achieving an average cooling of 8.5 °C against bare wall surface exterior on sunny days, climber foliage acted as a heat sink for the street canyon and the building shell. The posterior air gap (PAG) generated an effective insulation layer with average cooling of 2.5 °C against ambient air in sunny conditions. However, ambient air anterior to the green wall experienced minor warming up to 0.05 °C. Cooling was stronger on more solar-exposed aspect and under stronger insolation. Green walls steered humidification effect by 0.17 kPa on average on sunny days. Daily temperature oscillation was moderated most obviously at the building exterior with average 4.3 °C reduction in sunny conditions. Implications were drawn on climber-species selection and PAG provision to enhance the multi-dimensional thermal benefits of climber green wall.

Using passive acoustic monitoring to investigate the occurrence of cetaceans in a protected marine area in northwest Ireland

Under the EU Habitats Directive, cetacean species must be maintained at favourable conservation status in European waters. Whether this is achieved via protected area designation, curtailment of activities such as fishing or construction, or time restrictions on noise, it is dependent on understanding the temporal patterns in occurrence. Our ability to study this is often limited by the relatively short time-series of data available to researchers. This study uses nine years of passive acoustic monitoring data paired with environmental covariates to better understand the spatio-temporal dynamics of harbour porpoise and dolphin species using generalised estimating equations-generalised linear models (GEE-GLMs). This long-term time-series included periods of increased disturbance due to construction of an underwater gas pipeline in the area, enabling us to investigate the effect of construction on species occurrence. Harbour porpoise and dolphins occurred in every season, with detections peaking in winter. We found a negative association between dolphins and porpoises throughout the year. Inter-annual variation in occurrence was evident, with a cyclical bi-annual pattern highlighted for both species suggesting a complex pattern of movement. Construction activity had a significant negative effect on the presence of porpoise but not dolphins. However, no long-term decrease in detection rates of porpoise was recorded. This study highlights the importance of understanding what factors influence cetacean occurrence as well as the temporal scale of disturbance effects for planning and management of construction activities in coastal areas.

Allometric scaling of road accidents using social media crowd-sourced data

Traffic accidents in Lebanon are constantly harvesting lives, dramatically changing others, and traumatizing those of their beloved ones. Due to the lack of statutory authority in charge of collecting and reporting accident related data, the Lebanese Road Accident Platform (LRAP) is proposed in this work as a real-time online platform to collect crash events from social media. LRAP allows for autonomous data collection, classification and visualization without human intervention, and aims to help the authorities in laying down the appropriate measures for traffic accidents prevention. After being in production for the last four years, the data extracted from LRAP was used to study the allometric scaling of accidents with respect to different parameters such as district area, population size per district and road network length. Such approach offers a new perspective on traffic accidents’ scaling and behavior as a living organism as cities grow. A seasonality trend analysis is also provided to analyze temporal clustering patterns in crash occurrence.

Statins for primary prevention of cardiovascular disease and the risk of acute kidney injury.

PurposeTo investigate the risk of acute kidney injury (AKI) in subjects initiating statin therapy for primary prevention of cardiovascular disease (CVD).MethodsA nationwide cohort study using French hospital discharge and claims databases was performed, studying subjects from the general population aged 40 to 75 years in 2009, with no history of CVD and no lipid‐lowering drugs during the preceding 3‐year period, followed for up to 7 years. Exposure to statins (type, dose, and time since first use) and to other drugs for CVD risk was assessed. The primary outcome was hospital admission for AKI.ResultsThe cohort included 8 236 279 subjects, 818 432 of whom initiated a statin for primary prevention. During 598 487 785 person‐months exposed to statins, 700 events were observed, corresponding to an incidence of AKI of 4.59 per 10 000 person‐years (7.01 in men, 3.01 in women). AKI mainly occurred in the context of organ failure, sepsis, and genitourinary disease. A 19% increased rate of AKI (hazard ratio = 1.19, 95%CI: 1.08‐1.31) was observed in men exposed to statins, whereas no increase in the overall risk of AKI was observed in women. However, exposure to high‐potency statins was associated with a 72% to 116% increased risk in both genders and a dose‐effect relationship observed for rosuvastatin and atorvastatin. No temporal pattern of occurrence nor interaction with drugs for CVD risk was observed.ConclusionsAlthough the overall risk of AKI appears moderately increased, more attention should be paid to renal function in subjects taking statins for primary prevention both in clinical practice and from a research viewpoint.

Modeling spatially and temporally complex range dynamics when detection is imperfect

Species distributions are determined by the interaction of multiple biotic and abiotic factors, which produces complex spatial and temporal patterns of occurrence. As habitats and climate change due to anthropogenic activities, there is a need to develop species distribution models that can quantify these complex range dynamics. In this paper, we develop a dynamic occupancy model that uses a spatial generalized additive model to estimate non-linear spatial variation in occupancy not accounted for by environmental covariates. The model is flexible and can accommodate data from a range of sampling designs that provide information about both occupancy and detection probability. Output from the model can be used to create distribution maps and to estimate indices of temporal range dynamics. We demonstrate the utility of this approach by modeling long-term range dynamics of 10 eastern North American birds using data from the North American Breeding Bird Survey. We anticipate this framework will be particularly useful for modeling species’ distributions over large spatial scales and for quantifying range dynamics over long temporal scales.

Filling knowledge gaps in a threatened shorebird flyway through satellite tracking

Abstract Satellite‐based technologies that track individual animal movements enable the mapping of their spatial and temporal patterns of occurrence. This is particularly useful in poorly studied or remote regions where there is a need for the rapid gathering of relevant ecological knowledge to inform management actions. One such region is East Asia, where many intertidal habitats are being degraded at unprecedented rates and shorebird populations relying on these habitats show rapid declines. We examine the utility of satellite tracking to accelerate the identification of coastal sites of conservation importance in the East Asian–Australasian Flyway. In 2015–2017, we used solar‐powered satellite transmitters to track the migration of 32 great knots (Calidris tenuirostris), an “Endangered” shorebird species widely distributed in the Flyway and fully dependent on intertidal habitats for foraging during the non‐breeding season. From the great knot tracks, a total of 92 stopping sites along the Flyway were identified. Surprisingly, 63% of these sites were not known as important shorebird sites before our study; in fact, every one of the tracked individuals used sites that were previously unrecognized. Site knowledge from on‐ground studies in the Flyway is most complete for the Yellow Sea and generally lacking for Southeast Asia, Southern China and Eastern Russia. Synthesis and applications. Satellite tracking highlighted coastal habitats that are potentially important for shorebirds but lack ecological information and conservation recognition, such as those in Southern China and Southeast Asia. At the same time, the distributional data of tracked individuals can direct on‐ground surveys at the lesser known sites to collect information on bird numbers and habitat characteristics. To recognize and subsequently protect valuable coastal habitats, filling knowledge gaps by integrating bird tracking with ground‐based methods should be prioritized.

Temporal patterns of active fire density and its relationship with a satellite fuel greenness index by vegetation type and region in Mexico during 2003\u20132014

BackgroundUnderstanding the temporal patterns of fire occurrence and their relationships with fuel dryness is key to sound fire management, especially under increasing global warming. At present, no system for prediction of fire occurrence risk based on fuel dryness conditions is available in Mexico. As part of an ongoing national-scale project, we developed an operational fire risk mapping tool based on satellite and weather information.ResultsWe demonstrated how differing monthly temporal trends in a fuel greenness index, dead ratio (DR), and fire density (FDI) can be clearly differentiated by vegetation type and region for the whole country, using MODIS satellite observations for the period 2003 to 2014. We tested linear and non-linear models, including temporal autocorrelation terms, for prediction of FDI from DR for a total of 28 combinations of vegetation types and regions. In addition, we developed seasonal autoregressive integrated moving average (ARIMA) models for forecasting DR values based on the last observed values. Most ARIMA models showed values of the adjusted coefficient of determination (R2 adj) above 0.7 to 0.8, suggesting potential to forecast fuel dryness and fire occurrence risk conditions. The best fitted models explained more than 70% of the observed FDI variation in the relation between monthly DR and fire density.ConclusionThese results suggest that there is potential for the DR index to be incorporated in future fire risk operational tools. However, some vegetation types and regions show lower correlations between DR and observed fire density, suggesting that other variables, such as distance and timing of agricultural burn, deserve attention in future studies.

Spatial-Temporal Assessment of Environmental Factors Related to Dengue Outbreaks in São Paulo, Brazil.

Dengue fever, a disease caused by a vector‐borne flavivirus, is endemic to tropical countries, but its occurrence has been reported worldwide. This study aimed to understand important factors contributing to the spatial and temporal patterns of dengue occurrence in São Paulo, the largest municipality of Brazil. The temporal assessment of dengue occurrence covered the 2011–2016 time period and was based on climatological data, such as the El Niño indices and time series statistical tools such as the continuous wavelet transformation. The spatial assessment used Landsat 8 data for years 2014–2016 to estimate land surface temperature and normalized indices for vegetation, urban areas, and leaf water. Results from a cross correlation for the temporal analysis found a relationship between the sea surface temperature anomalies index and the number of reported dengue cases in São Paulo (r = 0.5) with a lag of +29 (weeks) between the climatic event and the response on the dengue incidence. This relationship, initially nonlinear, became linear after correcting for the lag period. For the spatial assessment, the linear stepwise regression model detected a low relationship between dengue incidence and minimum surface temperature (r = 0.357) and no relationship with other environmental parameters. The poor relationship might be due to confounding effects of socioeconomic factors as these seem to influence the spatial dynamics of dengue incidence. More testing is needed to validate these methods in other locations. Nevertheless, we presented possible tools to be used for the improvement of dengue control programs.

Temporal patterns in the acoustic presence of baleen whale species in a presumed breeding area off Namibia

The eastern Atlantic Ocean is considered to provide important breeding and wintering habitats for several migratory cetacean species. The spatio-temporal distributions and migratory behaviors of cetaceans off southern Africa are nevertheless still poorly understood. This study investigated the temporal patterns of acoustic occurrence of baleen whales in a presumed baleen whale breeding area off Namibia using passive acoustic recordings collected between November 2011 and May 2013. Our results show seasonal acoustic presence of humpback whales Megaptera novaeangliae, fin whales Balaenoptera physalus and Antarctic minke whales B. bonaerensis from November to January and from June to August. Their acoustic absence from February to May possibly indicates that most animals migrated to other areas (presumably in higher latitudes) in austral summer to feed. By contrast, Antarctic blue whales B. musculus intermedia were acoustically present throughout the recording period, indicating that part of the population remains at lower latitudes year-round. Our findings support the presumed ecological importance of the oceanic area off Namibia, providing (part of) a suitable cetacean wintering and, possibly, breeding range or migratory corridor. Furthermore, the occurrence of Antarctic blue and minke whales off Namibia, concurrent with their reported acoustic presence in high-latitude feeding areas, adds to growing evidence that baleen whale migration is not obligate but much more dynamic than has long been assumed.

Revealing the potential of a huge citizen-science platform to study bird migration

ABSTRACTThe currently best-known ornithological citizen-science platform is Cornell’s eBird, which provides crucial information for bird migration studies. Considering the solid validity of eBird data, and after a validation process, we comparatively explored the data available in the Brazilian-wide platform WikiAves for bird migration studies. We selected five migratory and four resident species as models, controlling for likely sampling biases derived from efforts by the platform collaborators. If data in WikiAves were adequate for migration studies, we respectively expected, after a between-platform comparison, similar yearlong seasonal and non-seasonal occurrence records of all migratory and resident species. Data analysis supported our expectations: eBird and WikiAves data showed consistent temporal occurrence patterns for all evaluated species. Therefore, we selected another six model-species showing literature inconsistency on their migratory behaviour, demonstrating for the first time the potential of a Brazilian citizen-science database – WikiAves – in unveiling geographically seasonal occurrence patterns of the understudied migratory bird species in Brazil. Our study highlights the general public relevance on reducing knowledge gaps about bird migration in Brazil, revealing a feasible strategy to overcome some current logistic barriers that preclude advances in South American bird migration studies, a currently underexplored research area, especially by Brazilian researchers.

Cystic Crypt Changes in Midgestational Human Vermiform Appendix: An Unrecognized Transient Histologic Feature.

Lewis and Huff briefly described the presence of "microcystic cryptitis" in some of fetal vermiform appendices (VA) at autopsy. We further characterized these crypt changes (CC), their timing of occurrence, and tested their association with infection/inflammatory conditions. Hematoxylin and eosin-stained slides of 345 VA were evaluated for the presence or absence of CC and their different morphologies. Autopsy reports were reviewed for evidence of amniotic fluid or fetal systemic infection and placental inflammatory conditions. Crypt dilatation with or without irregularity of the lumen, crypt dilatation with semiattenuated epithelium, intraluminal apoptotic debris and inflammatory cells, especially eosinophils, and foci of swirled spindled cells with calcifications or multinucleated giant cells were observed, either alone or in combination, in at least 58.5% (202/345) of the VA. CC began to appear at 17 weeks, peaked at 20 to 25 weeks (with up to 82% of VA exhibiting CC during this time), and followed by a steady decline beyond 28 weeks gestation. χ2 test of independence showed no significant association (P = .435; >0.05) between the presence and absence of CC and infection status of the fetus or placenta. The underrecognized CC of the developing fetal vermiform appendix (VA) showed distinct temporal pattern of occurrence and did not seem to be affected by the presence or absence of infection, which so far favored their being a part of the normal gut developmental process.

Hierarchical Development of Frailty and Cognitive Impairment: Clues Into Etiological Pathways.

Frailty and cognitive impairment (CI) are associated and often coexist in older adults. Whether temporal patterns of occurrence reflect different etiologies remain unknown. Participants from the National Health and Aging Trends Study were assessed annually (2011-2016) for frailty (Fried's criteria) and CI (bottom quintile of clock drawing test or immediate and delayed recall; proxy-report of dementia diagnosis or AD8 ≥ 2). We used the Fine & Gray model to identify correlates of frailty onset before CI, CI onset before frailty, and frailty-CI co-occurrence, accounting for death as a competing risk. Of 3,848 free of frailty, CI, and dementia at baseline, 2,183 (61.2%) developed neither frailty nor CI during the 5-year follow-up; 343 (8.3%) developed frailty first; 1,014 (24.4%) developed CI first; and 308 (6.0%) developed frailty-CI co-occurrence. Incident dementia, as a marker of underlying neuropathologies, was associated with greater likelihood of CI onset first (subdistribution hazard ratios [SHR] = 2.60, 95% confidence interval [ci] 2.09 to 3.24), and frailty-CI co-occurrence (SHR = 8.77, 95% ci 5.79 to 13.28), but lower likelihood of frailty onset first (SHR = 0.38, 95% ci 0.21 to 0.68). Number of comorbidities was only associated with frailty occurrence first (1 comorbidity: SHR = 2.51, 95% ci 1.15 to 5.47; 4+ comorbidities: SHR = 6.48, 95% ci 2.78 to 15.48). Different patterns of frailty and CI occurrence exist, and dementia-related pathologies and comorbidities may be important correlates of order of emergence, potentially reflecting different etiologies. Future investigation into relationships between these patterns and dementia subtypes and related pathologies is needed to elucidate etiologic pathways and to provide new targets for prevention, intervention, and risk screening.

A Comparison of Burned Area Time Series in the Alaskan Boreal Forests from Different Remote Sensing Products

Alaska’s boreal region stores large amounts of carbon both in its woodlands and in the grounds that sustain them. Any alteration to the fire system that has naturally regulated the region’s ecology for centuries poses a concern regarding global climate change. Satellite-based remote sensors are key to analyzing those spatial and temporal patterns of fire occurrence. This paper compiles four burned area (BA) time series based on remote sensing imagery for the Alaska region between 1982–2015: Burned Areas Boundaries Dataset-Monitoring Trends in Burn Severity (BABD-MTBS) derived from Landsat sensors, Fire Climate Change Initiative (Fire_CCI) (2001–2015) and Moderate-Resolution Imaging Spectroradiometer (MODIS) Direct Broadcast Monthly Burned Area Product (MCD64A1) (2000–2015) with MODIS data, and Burned Area-Long-Term Data Record (BA-LTDR) using Advanced Very High Resolution Radiometer LTDR (AVHRR-LTDR) dataset. All products were analyzed and compared against one another, and their accuracy was assessed through reference data obtained by the Alaskan Fire Service (AFS). The BABD-MTBS product, with the highest spatial resolution (30 m), shows the best overall estimation of BA (81%), however, for the years before 2000 (pre-MODIS era), the BA sensed by this product was only 44.3%, against the 55.5% obtained by the BA-LTDR product with a lower spatial resolution (5 km). In contrast, for the MODIS era (after 2000), BABD-MTBS virtually matches the reference data (98.5%), while the other three time series showed similar results of around 60%. Based on the theoretical limits of their corresponding Pareto boundaries, the lower resolution BA products could be improved, although those based on MODIS data are currently limited by the algorithm’s reliance on the active fire MODIS product, with a 1 km nominal spatial resolution. The large inter-annual variation found in the commission and omission errors in this study suggests that for a fair assessment of the accuracy of any BA product, all available reference data for space and time should be considered and should not be carried out by selective sampling.

A hundred years of rabies in Kenya and the strategy for eliminating dog-mediated rabies by 2030.

Background: Rabies causes an estimated 59,000 human deaths annually. In Kenya, rabies was first reported in a dog in 1912, with the first human case reported in 1928. Here we examine retrospective rabies data in Kenya for the period 1912 - 2017 and describe the spatial and temporal patterns of rabies occurrence in the country. Additionally, we detail Kenya's strategy for the elimination of dog-mediated human rabies by 2030. Methods: Data on submitted samples and confirmed cases in humans, domestic animals and wildlife were obtained from Kenya's Directorate of Veterinary Services. These data were associated with the geographical regions where the samples originated, and temporal and spatial trends examined. Results: Between 1912 and the mid 1970's, rabies spread across Kenya gradually, with fewer than 50 cases reported per year and less than half of the 47 counties affected. Following an outbreak in the mid 1970's, rabies spread rapidly to more than 85% of counties, with a 4 fold increase in the percent positivity of samples submitted and number of confirmed rabies cases. Since 1958, 7,584 samples from domestic animals (93%), wildlife (5%), and humans (2%) were tested. Over two-thirds of all rabies cases came from six counties, all in close proximity to veterinary diagnostic laboratories, highlighting a limitation of passive surveillance. Conclusions: Compulsory annual dog vaccinations between 1950's and the early 1970's slowed rabies spread. The rapid spread with peak rabies cases in the 1980's coincided with implementation of structural adjustment programs privatizing the veterinary sector leading to breakdown of rabies control programs. To eliminate human deaths from rabies by 2030, Kenya is implementing a 15-year step-wise strategy based on three pillars: a) mass dog vaccination, b) provision of post-exposure prophylaxis and public awareness and c) improved surveillance for rabies in dogs and humans with prompt responses to rabies outbreaks.

Relative influence of environmental factors on the timing and occurrence of multi-species coral reef fish aggregations.

Reef configuration and hydrodynamics were identified as the principle physical drivers behind coral reef fish aggregations on a mid-shelf patch reef in the northern section of the Great Barrier Reef (-16.845°, 146.23°). The study was carried out over a six-year period at a large reef pass on the oceanic margin of the northern Great Barrier Reef. Over this period (February 2006 –December 2012) tidal state, moon phase and surface seawater temperature were monitored. The timing of sampling was organised to assess variation in physical environment at daily, monthly, seasonal and annual time scales. Over these time scales, temporal patterns of occurrence of 10 species of coral reef fish from 5 families representing 5 defined trophic groups were monitored. The study incorporated 1,357 underwater visual census counts involving 402,370 fish and these estimates were collated with data on tidal state, water temperature, lunar and seasonal periodicity. Aggregated boosted regression trees analysed the univariate responses of fish abundance and species richness to the variation in the physical environment of the reef pass. Flood tides or when water flows from open water through the pass and into the Moore Reef lagoon had 2.3 times as many fish and 1.75 times as many species compared to counts made on ebb tides. Fish abundance was highest in late winter and spring months (Austral calendar), but notably when water temperatures were below the long-term mean of 27°C. Multivariate regression trees and Dufrêne-Legendre indicator predicted 4 out of 10 times the occurrence of all 10 species at any temporal scale ranging from hours to years. Flood tides were the principle driver underlying the occurrence of all 10 species regardless of their trophic classification and produced distinct seasonal assemblages, indicative of fishes aggregating to forage and reproduce.

A hundred years of rabies in Kenya and the strategy for eliminating dog-mediated rabies by 2030

Background: Rabies causes an estimated 59,000 human deaths annually. In Kenya, rabies was first reported in a dog in 1912, with the first human case reported in 1928. Here we examine retrospective rabies data in Kenya for the period 1912 – 2017 and describe the spatial and temporal patterns of rabies occurrence in the country. Additionally, we detail Kenya’s strategy for the elimination of dog-mediated human rabies by 2030. Methods: Data on submitted samples and confirmed cases in humans, domestic animals and wildlife were obtained from Kenya’s Directorate of Veterinary Services. These data were associated with the geographical regions where the samples originated, and temporal and spatial trends examined. Results: Between 1912 and the mid 1970’s, rabies spread across Kenya gradually, with fewer than 50 cases reported per year and less than half of the 47 counties affected. Following an outbreak in the mid 1970’s, rabies spread rapidly to more than 85% of counties, with a 4 fold increase in the percent positivity of samples submitted and number of confirmed rabies cases. Since 1958, 7,584 samples from domestic animals (93%), wildlife (5%), and humans (2%) were tested. Over two-thirds of all rabies cases came from six counties, all in close proximity to veterinary diagnostic laboratories, highlighting a limitation of passive surveillance. Conclusions: Compulsory annual dog vaccinations between 1950’s and the early 1970’s slowed rabies spread. The rapid spread with peak rabies cases in the 1980’s coincided with implementation of structural adjustment programs privatizing the veterinary sector leading to breakdown of rabies control programs. To eliminate human deaths from rabies by 2030, Kenya is implementing a 15-year step-wise strategy based on three pillars: a) mass dog vaccination, b) provision of post-exposure prophylaxis and public awareness and c) improved surveillance for rabies in dogs and humans with prompt responses to rabies outbreaks.

Dynamics of forage ingestion, oral processing and digesta outflow from the rumen: a development in a mechanistic model of a grazing ruminant, MINDY

AbstractDetailed representation of ingesta inflow to and digesta outflow from the rumen is critical for improving the modelling of rumen function and herbage intake of grazing ruminants. The objective of the current work was to extend a mechanistic model of a grazing ruminant, MINDY, to simulate the dynamic links between ingestive and digestive processes as affected by forage and sward features (e.g. sward structure, herbage chemical composition) as well as the internal state of the animal. The work integrates existing aspects of forage ingestion, oral physiology and rumen digestion that influence ingesta characteristics and digesta outflows from the rumen, respectively. The paper describes the structure and function of the new development, assessing the new model in terms of dynamic changes of oral processing of ingesta and rumen dilution rate under different grazing contexts. MINDY reproduces characteristics of ingesta inflow to and digesta outflow from the rumen of grazing ruminants, achieving temporal patterns of occurrence within and between meals, similar to those for grazing animals reported in the literature. The model realistically simulates changes in particle size distribution of the ingestive bolus, bolus weight and rumen dilution rate in response to contrasting grazing management regimes. The new concepts encoded in MINDY capture the underlying biological mechanisms that drive the dynamic link between ingestion and digestion patterns. This development advances in the understanding and modelling of grazing and digestive behaviour patterns of free-ranging ruminants.

A hundred years of rabies in Kenya and the strategy for eliminating dog-mediated rabies by 2030

Background: Rabies causes an estimated 59,000 human deaths annually. In Kenya, rabies was first reported in a dog in 1912, with the first human case reported in 1928. Here we examine retrospective rabies data in Kenya for the period 1912 – 2017 and describe the spatial and temporal patterns of rabies occurrence in the country. Additionally, we detail Kenya’s strategy for the elimination of dog-mediated human rabies by 2030. Methods: Data on submitted samples and confirmed cases in humans, domestic animals and wildlife were obtained from Kenya’s Directorate of Veterinary Services. These data were associated with the geographical regions where the samples originated, and temporal and spatial trends examined. Results: Between 1912 and the mid 1970’s, rabies spread across Kenya gradually, with fewer than 50 cases reported per year and less than half of the 47 counties affected. Following an outbreak in the mid 1970’s, rabies spread rapidly to more than 85% of counties, with a 4 fold increase in the percent positivity of samples submitted and number of confirmed rabies cases. Since 1958, 7,584 samples from domestic animals (93%), wildlife (5%), and humans (2%) were tested. Over two-thirds of all rabies cases came from six counties, all in close proximity to veterinary diagnostic laboratories, highlighting a limitation of passive surveillance. Conclusions: Compulsory annual dog vaccinations between 1950’s and the early 1970’s slowed rabies spread. The rapid spread with peak rabies cases in the 1980’s coincided with implementation of structural adjustment programs privatizing the veterinary sector leading to breakdown of rabies control programs. To eliminate human deaths from rabies by 2030, Kenya is implementing a 15-year step-wise strategy based on three pillars: a) mass dog vaccination, b) provision of post-exposure prophylaxis and public awareness and c) improved surveillance for rabies in dogs and humans with prompt responses to rabies outbreaks.