Unique Issues in Emergency Medicine 657 Ethics and end-of-life issues Special ethical issues in teaching hospitals Unique ethical dilemmas arise in academic medical centers as a function of the training environment gastritis antrum diet cheap doxazosin 4mg overnight delivery. The inherent nature of apprenticeship in medical education sometimes conflicts with patient expectations that their care be delivered by only the most well-trained individuals gastritis diet àâòîðèà order 2mg doxazosin with amex. Ethical issues arising from the teaching environment require special attention by both the instructor and learner gastritis acid diet 2mg doxazosin otc. Informed consent Legal and ethical principles mandate that physicians obtain informed consent for all treatments delivered gastritis daily diet buy discount doxazosin 2mg online. While this initial consent implies that patients understand the benefits of such care gastritis diet õàðüêîâ doxazosin 1 mg for sale, physicians should make every effort to review the risks of all significant interventions gastritis upper left abdominal pain buy 2mg doxazosin overnight delivery. Patients should confirm that they feel comfortable with their decision, acknowledging that their choice was voluntary and without duress. Both medical staff and family members can unduly influence patients to provide consent that is neither authentic nor autonomous. It is acceptable and ethically responsible to ask patients if they felt that they made their decision without feeling pressured. An ethical dilemma exists between the need to respect the integrity and autonomy of patients and family members, and the need to train health care providers. Prior to performing procedures on the newly deceased, the following considerations should be addressed: 1. The teaching of life-saving skills should be the culmination of a structured training sequence, performed under close supervision and in accordance with the wishes and values of all involved parties. Physicians should attempt to assess if the deceased had expressed preferences for the handling of his or her body after death. In the absence of expressed preferences or surrogate consent, physicians should not perform procedures for training purposes. Ethics and end-of-life issues Research ethics and the emergency exception to consent Teaching hospitals often conduct research activity as part of their academic mission. Patients identified as potential research subjects for studies must first provide informed consent prior to their participation. It is sometimes difficult to obtain consent for emergency medicine research projects, however, as patients often present gravely ill and alone. They may lack the decision-making capacity necessary for consent and have no surrogate available to speak on their behalf. This complicates emergency medicine research, as it limits the ability to enroll subjects and conduct studies. Additionally, patients who might benefit from novel interventions are sometimes precluded from receiving such care when they are unable to provide consent. While these guidelines offer researchers a method by which to conduct emergency medicine studies, they provide important ethical assurance that research subjects will be protected and respected. Pearls of wisdom: issues of professional ethics for physicians-in-training Do not lie. The pressure to perform well in training programs often leads students and residents to misrepresent their knowledge or actions. Avoid the trap of embellishing history and physical examination details in order to appear more complete to your evaluators. They expect the best care possible and will assume that students or residents have more training than they actually do. Clearly describe your role on the health care team and be honest about your level of training. Learners Procedures on the newly dead Recently deceased patients are occasionally used to teach life-saving, invasive procedures to 658 Unique Issues in Emergency Medicine may be asked to perform procedures they have never seen or read about previously. Ask for supervision for procedures requiring skills you have not yet mastered, and refuse to perform them without assistance. Sometimes you may feel that an ethical issue has arisen, but others on the team seem unaware or unconcerned. It may result in a learning moment for you, as the attending physician may not have taken the time to explain his or her decision-making process. In other instances, you may feel it necessary to seek additional guidance elsewhere. Hospital ethics committees are available for consultation by any member of the health care team, including nurses, ancillary staff and physicians-in-training. Acting without asking: an ethical analysis of the Food and Drug Administration waiver of informed consent for emergency research, Ann Emerg Med 1999;33(2):218Â223. Consent and refusal in an urban American emergency department: two case studies, Acad Emerg Med 2001;8(3): 278Â281. Emergency determination of decision-making capacity, Acad Emerg Med 2001;8(3):282Â284. Along with a relatively high likelihood of malpractice claims, emergency physicians often interact with police as they assess and treat trauma patients. This chapter introduces the most common legal concepts that arise in emergency medicine. The difficulty with any discussion of legal issues on a general level lies in the lack of consistency between the various legal systems. Broadly speaking, there are two main divisions  federal law and state law  and each of these divisions is further subdivided into criminal, civil, and administrative sections. The laws governing any particular issue may differ depending on the particular state involved (or the federal government) and whether criminal, civil, or administrative rules apply. This inconsistency results in a certain ambiguity when discussing legal issues in a general sense, and mandates that physicians understand the specific laws that govern in their practice location. To give informed consent, a patient must have sufficient information on which to base a decision about treatment. The legal determination of whether the physician obtained informed consent varies from state to state, but relies on terms such as "appropriate" and "reasonable," thus leaving the issue far from clear in any given case. Emergency exceptions to consent Certain patients are unable to either consent to or refuse treatment based on their inability to participate meaningfully in the informed consent process. This typically occurs due to age, intoxication, underlying medical conditions, or acute changes in mental status. When the patient cannot provide consent, all states have emergency exceptions to the consent process. Patients medically unable to express consent are presumed to consent to emergency stabilizing treatment. Conversely, physicians must obtain consent prior to procedures and treatment or risk a charge of battery. In these situations, the physician can assume consent for any necessary stabilizing treatment. In the rare case of a guardian or parent refusing to consent to life-saving treatment needed to stabilize a child, physicians should generally provide necessary treatment and obtain a court order after the fact. Note that age by itself does not necessarily preclude the ability to consent, as there are conditions that allow minors to make their own medical decisions. These conditions vary from state to state, but often include the ability to consent without parental knowledge to treatment for sexually transmitted illnesses, pregnancy, drug and alcohol dependency, rape, and mental health concerns. Emancipated minors, individuals who the law recognizes as adults despite their age, also can consent or refuse treatment without parental involvement. Circumstances that allow minors to apply for legal emancipation vary, but often include active duty in the armed forces, marriage, pregnancy, and parenthood. Patients who "elope" should be discussed among involved care providers, including nursing and ancillary staff, to determine if the patient reasonably appeared to have the capacity to withdraw consent and leave. Patients who do not, such as the patient above, must be searched for and retrieved as soon as possible. Unfortunately, unless these orders are explicit, it often remains unclear as to what exactly the patient would want for conditions less severe than cardiac arrest. If the patient displays signs of impending respiratory failure, should they be intubated? If they are hypotensive from unstable ventricular tachycardia, should they be cardioverted? What constitutes "actual knowledge" may be debated in individual cases, but generally refers to situations in which a physician has personally seen the advance directive even though it is not currently present. Informed refusal Patients with decision-making capacity may withdraw consent for treatment at any time. When a patient withdraws consent, the physician must again determine his or her capacity to do so. Patients with impaired decisionmaking capacity cannot provide an informed refusal, and the physician has a duty to provide stabilizing treatment. Occasionally, patients do not understand the various treatment options or the potential for deterioration of their condition. In California, for example, patients who are suicidal, homicidal, or gravely disabled may be detained up to 72 hours for psychiatric evaluation. During this period, these patients may receive treatment necessary to stabilize a condition brought on by a suicide attempt, and they may be restrained by physical or chemical means necessary to protect themselves or others. The procedure for involuntarily detaining a patient is complex, and physicians should become thoroughly familiar with the laws in their area, carefully document the events that required detainment, and the methods of restraint implemented. Privacy and confidentiality Another common legal issue arising during patient care involves privacy and confidentiality issues. While the medical records are typically owned by the hospital, the information within them is considered property of the patient. In general, medical information cannot be shared with a third party without the consent of the patient unless such information is necessary for medical treatment. This includes releasing information to other family members, insurance companies, and employers. Exceptions to this exist, as all states have mandatory reporting of victims of violence and of certain health conditions. Emergency physicians must be careful to obtain consent from patients prior to speaking with other family members, friends, or employers. Patients unable to consent due to medical conditions represent a special case that the courts have yet to fully explore. Generally, physicians should proceed with the assumption of what a reasonable person in a similar situation would want with regard to confidentiality. For example, refusing to update a spouse on the status of a criticallyinjured patient because the patient is unable to give consent for the release of medical information seems unreasonable. While the courts have yet to determine many issues in this area, they typically allow discretion when a physician acts in the best interest of an incapacitated patient. Similarly, certain medical information, such as drug or alcohol tests in the hands of civil authorities, may result in serious consequences to some patients. Legal aspects of emergency care the criminal justice system Emergency physicians often interact with police, detectives, district attorneys, and criminal defense attorneys. Interacting with the criminal justice system is an inevitable part of emergency medicine, and Table 44. Those in custody retain their rights to refuse medical treatment (barring altered mental status). Most police agencies prefer to obtain their own blood or urine specimens for legal reasons. Legal issues and practice suggestions Physicians must report children and certain at-risk adults (elderly, cognitively-impaired, etc. Many states require physicians to report victims of domestic violence or animal attacks. Physician must either comply with subpoena or contact the party issuing the subpoena (usually prosecutor or defense attorney) and make alternative arrangements. Do not cut through bullet holes in clothing, destroy or discard personal belongings, or place chest tubes through gunshot or stab wounds. Refrain from describing wounds as "entry" or "exit" or speculating on bullet trajectory unless specifically trained to do so. In the medical record, use the term "alleged" because the physician has no direct knowledge of the events. Consider transferring to specialized sexual assault referral center if available after appropriate contacts have been made and safe transport is arranged. Physician evaluates trauma patient prior to evidence collection (victim of gunshot wound, etc. These patients may have suffered significant injury or death due to delays in finding emergency care. The parties usually rely on expert witness testimony to establish or refute these elements. This often results in highly technical testimony that can be confusing to jury members. Additionally, the information on which these experts draw their conclusions comes primarily from the medical record, which may be illegible, incomprehensible, or incomplete. This frequently results in not only disagreements over issues of judgment, but also debates over issues of fact. For example, the plaintiff argues that peripheral pulses were not checked while the defense claims they were. The medical record provides the most persuasive evidence of who is more likely to be correct. Settlement represents a risk reduction strategy in that the plaintiffs recover some award and the defendants prevent an unexpectedly high judgment against them. Of those cases that are decided by a jury, approximately 70Â90% result in verdicts for the defense. Despite these favorable odds, most physicians involved in a malpractice claim report it as a distinctly unpleasant experience. This has resulted in substantial interest in methods to reduce the number of claims. Despite the legal requirements to show both breach of duty and causation, more patients without evidence of negligence file suit than do those who suffered negligent care.
Furthermore gastritis diet during pregnancy doxazosin 2 mg otc, Pima County does not permit use of motorized vehicles on trails gastritis eating habits purchase doxazosin 1mg with mastercard, cross-country gastritis symptoms heart purchase 1mg doxazosin free shipping, or on unsurfaced roadways where restrictions have been posted or signed at Pima County parks and recreation areas (see Pima County Parks Rules gastritis diet 5 bites purchase 4mg doxazosin with visa, Ch gastritis symptoms livestrong 4 mg doxazosin with mastercard. Similar to Pima County ordinances chronic gastritis stomach discount doxazosin 4 mg fast delivery, motorized vehicles may not be operated in any publicly owned wash with the exception of instances where an otherwise legal and open roadway crosses such a wash. Also, operation of a motorized vehicle that contributes visible dust pollution that then crosses into other residential, recreational, or business areas is prohibited (Marana Town Code Chapter 12-4-2). Town of Oro Valley the Town of Oro Valley does not permit the use of off-road motorized vehicles on any undeveloped public or private property, including washes, desert areas, and non-paved empty lots (Oro Valley Town Code Section 11-3-17). This decal applies to any vehicle weighing 1,800 pounds and/or with an engine > 49 cubic centimeters. The Travel Management Rule mandates that all national forests need to have a sustainable roads management plan that includes the minimum roads network required to serve the needs of constituents and maintain the ecological integrity of the national forest. To that end, the Coronado National Forest has created a Motor Vehicle Use Maps, by district, that indicate which routes are open to motorized traffic, during which seasons, and to which types of motorized traffic. It is the responsibility of the motorized vehicle user to understand what is allowed, based on where they are. In some cases, there is not an evident gate or signage signaling a change in land ownership. Open areas are those for which any legally operated vehicle is allowed at all times at any location, while a limited area means that there are restricted times, areas, or particular kinds of vehicular use. They include impacts to soils, vegetation, wildlife, water quality, and air quality that is affected by dust and exhaust (Ouren et al. Noise pollution can disrupt the activities of both people and wildlife (Ouren et al. Where washes are incised, they also provide opportunities to travel unseen as steep banks can obscure the line of sight from a distance, making it much more difficult to detect intrusions while they are happening. The locations of many known Pima pineapple cacti populations (Coryphantha sheeri var. If seen, it may still be crushed by travel because, unlike large cacti, it poses very little threat to vehicles and operators that may run over it. These changed circumstances are any processes or developments that could be reasonably anticipated to impact a covered species, covered species habitat, or the geographic area included in the conservation plan. In this or a similar case, prudence calls for being conservative when evaluating if a changed circumstance has occurred. In many of these cases, it is unlikely that an evaluation of the impact would meet the threshold determining that a changed circumstance has been triggered. This information could then be used in property or area specific 8 management plans and to monitor change over time for this type of land use and its associated impacts. Property assessments County staff regularly conduct property assessments and inventories on County lands. These visits occur on both new acquisitions and on established County conservation lands, and so include a combination of first-time visits and repeated visits to the same general area. Property assessments have a variety of objectives including gaining a better understanding of the distributions of Covered Species and other species of conservation concern; documenting the occurrence and status of sensitive habitat elements such as springs, riparian vegetation, and key plant communities; and generally enhancing knowledge of the biodiversity and natural resources contained on County lands. Further, staff document the status of infrastructure on County lands and a host of threats. Observations of this sort are shared with the appropriate land managers within the County and/or law enforcement. Pima Association of Governments staff and Pima County staff map surface water quarterly along Cienega Creek and Davidson Canyon in the Cienega Creek Natural Preserve. As indicated above, observations will be collected via a digital datasheet and sent to the relevant land manager. After data are in the geodatabase, surveyors check the data for any inaccuracies or errors before the data are finalized. Master of Science Thesis, School of Natural Resources, University of Arizona, Tucson, Arizona. Environmental effects of off-highway vehicles on Bureau of Land Management lands: a literature synthesis, annotated bibliographies, extensive biographies, and internet resources. Off-highway vehicle recreation in drylands: A literature review and recommendations for best management practices. Within a wash and closer than ј mile to any structure (for private property exception) No use on any property owned or leased by the Town other than a public roadway Publicly owned washes (except in legal road crossings) Operation that contributes visible dust pollution that extends across property lines into other areas Within ј mile of a structure while driving off of the roadway A-1 Enforcement Pima County Sheriff Code/Ordinance/Rule* Pima County Ordinance 9. Forest Service See relevant Motor Vehicle Use Maps by Forest District No use in wilderness or other special designated areas Arizona State Land Department Arizona Game and Fish Department Coronado National Forest, U. Low, medium, or high vulnerability bins are based on how widespread or common covered species may be and/or the sensitivity of covered species habitat elements. B-3 Pima County Multi-species Conservation Plan: 2019 Annual Report Appendix 14 Pima County Climate Monitoring Protocol 40 pages Pima County Ecological Monitoring Program Climate Monitoring Protocol March 2020 Prepared by Pima County Office of Sustainability and Conservation Staff: Jeff M. Gicklhorn Cover photo: Monsoon storm over the Santa Catalina Mountains on Six Bar Ranch Recommended citation: Gicklhorn, J. Distribution of Pima County conservation lands with elevation and soils strata shown. Rain gauges maintained by Pima County, plus several additional maintained by partners. Percent monsoonality of 15 soil-veg plots by elevational strata and geographic region for the seven historic climate-monitoring periods. Specific uplands vegetation and soils monitoring plots established in either 2017 or 2018 used in the example below. Annual weather patterns are often quite variable, tending to provide a feast one year and famine the next. However, changes in long-term climate can lead to large-scale structural change in plant and animal species abundance, distribution, and community composition and structure. This protocol discusses the proposed monitoring methods as well as several data quality considerations for monitoring long-term climate on County conservation lands. We propose to track precipitation on a five-year cycle at multiple spatial scales from an individual vegetation and soils monitoring plot all the way up to climate regions roughly aligned with major watersheds. Summer monsoonal precipitation in highly spatially variable in southern Arizona, therefore we will expend the majority of effort quantifying seasonal precipitation. We will also summarize short and long-term drought effects at larger spatial scales. Lastly, we propose a method to establish a pre-permit (2016) climate baseline in order compare contemporary climate values against for future trend analysis. McMahan (University of Arizona, Climate Assessment for the Southwest) for discussion and feedback on developing this protocol. Both variable annual weather and longterm local climate dictate where and when that critical water is available to plant and animal species. Temperature, combined with water availability, dictates evaporative demand and drought stress for species; where lack of suitable access to water or extended temperatures outside the normal range of variability can lead to mortality. Therefore, monitoring local climate, and subsequently how climate change over time, is essential to understanding monitoring data associated with plant and wildlife species and their habitats. Southeastern Arizona has a bimodal rainfall distribution, with two defined wet periods during the winter (Nov-Mar) and summer monsoon (Jun-Sept) (McPhee et al. Interannual variability in precipitation combined with the highly localized nature of monsoonal rainfall patterns means that water availability can vary both spatially, across relative small geographical areas, and temporally, within and across seasons and years. This variability can lead to one localized area being inundated with flash flooding, where an area nearby may see little to no rainfall. Additionally, upstream rainfall may be accessible to riparian plant or wildlife species downstream far from where the precipitation event actually occurred. Annual weather variability directly and indirectly affects both covered and invasive species populations and their habitats; therefore, monitoring how local and regional climate is changing over time is essential to interpreting changes in those populations and habitats over the 30-year lifetime of the Section 10 permit. Understanding the climactic conditions that these plots experience over time will allow for better interpretation of detected changes and trends in vegetation and soils composition and structure over time. Additionally, understanding trends in local climate will be useful in interpreting species-specific monitoring results, such as for Sonoran desert tortoise (Gopherus morafkai) occupancy monitoring and Pima pineapple cactus (Coryphantha scheeri var. These changes include a shift towards fewer but larger magnitude monsoon precipitation events, as well as decreased winter precipitation (Garfin et al. Warmer temperatures, especially winter nighttime low temperatures, along with the increase in frequency and duration of high-temperature events. Native plants and animals are expected to face longer, hotter, and more frequent drought events, potentially leading to changes in species abundance and overall community composition. Tracking long-term trends in local and regional climate will allow County staff to characterize actual climate conditions for monitored resources, rather than modelled conditions. Observations collected by Pima County may be useful to others in calibrating new regional climate models. Lastly, understanding local climate trends can benefit other County programs, such as the Range Management program. This program requires data about annual precipitation in specific locations (County ranch properties), however changing climate trends may determine how management is implemented going forward. For example, Sustainability program staff work with the Facilities and Transportation departments to help them understand climate model projections for our area. Forecasted increases in localized rainfall intensity have considerable implications for County-managed infrastructure projects. Our dataset may help to determine to what degree those models are accurate, as well as to define the longer-term range of variability for our region. Additionally, the Range Management program currently utilizes data from a network of passive rain gauges across County ranch properties to make within-year range management decisions. Informed decision making requires access to current data and due to the remote nature of the gauges, data gaps can occur due to lack of staff resources. The proposed climate monitoring protocol and dataset may support work to identify the most accurate local or regional climate model correlated with County conservation properties and provide a long-term record of the range of variability in precipitation across County ranch lands that may assist in future range management decision making. This protocol will 1) define methods by which long-term climate metrics (precipitation and drought) will be monitored and summarized across County conservation lands at multiple spatial scales, 2) discuss climate data storage and management for future interpretation of long-term trends observed at soil-vegetation plots and other monitoring sites, and 3) propose the methodology for establishing a pre-permit climate baseline for future trend analyses. Where possible, the data may contribute to the greater understanding of long-term climate monitoring through collaborations and partnerships. A historic climate baseline (pre-2016 permit) will also be quantified for future trend analyses (discussed below). These lands are located across five major watersheds, which include the Altar-Brawley Wash, San Pedro River, Cienega Creek, and upper and lower Santa Cruz River, and range in elevation from 425 to 1870 m (1400 to 6130 ft). County conservation lands do not include higher elevations of the mountain ranges within eastern Pima County and thus snow makes up a relatively minor portion of the annual precipitation across County lands. Assessing climate at multiple spatial scales requires first defining those categories and scales. County conservation lands contain primarily strata 200-400, and the final 100 vegetation and soils monitoring plots are distributed within three rock fragment classes across these three strata respectively (Figure 2). Classes 402 and 403 were combined as they represented a smaller area than the 401 rock fragment class. County conservation lands and subsequently vegetation and soils monitoring plots are also grouped into geographic regions, which experience distinct climates, roughly correlating to major watersheds identified above (Table and Figure 2). However, several properties were grouped due to their geographic proximity rather than watershed. For example, Rancho Seco is split between the Brawley Wash and Upper Santa Cruz watersheds, however due to its proximity to Sopori Ranch, we have grouped it into the Southwest region. We propose to summarize drought effects at the climate region (watershed) and elevational strata level. Additionally, summarizing 3 precipitation and drought at the region and elevational strata levels will allow for higher-level interpretation and comparison of monitoring data across the suite of County conservation lands. For example, local research efforts have already detected climate change driven changes in flowering plant phenology in eastern Pima County, where plant communities at different elevations are responding differently to novel climate regimes (Rafferty et al. A preliminary study examining pre-permit climate between regions and elevational strata has already indicated differences in precipitation, temperature, and seasonality across scales (Preliminary Studies section below). Our climate monitoring efforts may facilitate regional and elevational comparisons of trends in vegetation composition and structure over time. Region Preserve Name Northwest Tucson Mountain Park Tortolita Mountain Park Sweetwater Preserve * Northeast A7 Ranch Oracle Ridge Buehman Canyon / Tesoro Nueve Six Bar Ranch M Diamond Ranch Southeast Bar V Ranch Clyne Ranch Cienega Creek Natural Preserve Empirita Ranch Colossal Cave Mountain Park Sands Ranch Southwest Canoa Ranch Sopori Ranch Rancho Seco Marley Ranch (Cerro Colorado parcels) * West Diamond Bell Ranch Madera Highlands Kings 98 Ranch Marley Ranch (Serrita parcels) Buckelew Properties Old Hayhook Ranch * Indicates that no vegetation and soils monitoring plots have been or will be established on these properties. Climate Metrics this protocol focuses primarily on quantifying local precipitation, due to its highly variable spatial and temporal nature in southeastern Arizona, and secondarily drought, which integrates precipitation and temperature. National-level gridded climate products have considerable difficulty accurately estimating monsoon precipitation in southern Arizona, whereas winter precipitation is more accurately estimated (Weiss and Crimmins 2016). Climate data at each uplands vegetation and soils monitoring plot location will be summarized by season (summer = June  September, winter = October  May) for precipitation and by month for temperature, with each unit (month or season) averaged across the specified five-year monitoring period. The climate-monitoring schedule is offset earlier than the upland vegetation and soils monitoring schedule due to the time lag associated with seasonal precipitation and vegetation growth (Ogle and Reynolds 2004). The first panel of monitoring plots were established beginning in summer of 2017 and will finish in winter of 2021; therefore, the first five-year climate monitoring period will begin winter 2016 (Oct 2016  May 2017) and end summer 2021 (June 2021  September 2021), and will be submitted concurrently with the 2021 annual report in March 2022. Monitoring periods for the pre-permit baseline are discussed in the relevant section below. Many of these stations were installed in the 1980s, however some have been installed as recently as the early 2000s. Ninety-six stations are located along major waterways and mountain canyons to provide instantaneous data when either precipitation or stream flow are detected. These gauges are located on remote county conservation lands with active grazing leases, are checked twice a year to determine seasonal precipitation totals. The data from both types of gauges can potentially be leveraged to compliment the proposed methods in the protocol, by correlating modeled precipitation values to empirical values collected from weather stations. Available Climate Products There are a number of freely available model-based, national-level, gridded climate products available. These products are national in scale and therefore the spatial resolution associated with each may be quite large (1-4 km). This spatial variation suggests that one product may be better correlated with empirical rain gauge data, especially during the notoriously unpredictable summer monsoon season (June 15  Sept 30). These products are known to be relatively accurate at larger scales (watersheds, counties, states, etc), but have challenges modeling climate at very small spatial scales. This consideration should be taken into account when determining which gridded data product to use (Daly 2006).
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Agriculture & Aquaculture  Threats from farming and ranching as a result of agricultural expansion and intensification gastritis eating plan discount doxazosin 4mg line, including silviculture gastritis symptoms lower back pain cheap doxazosin 2 mg overnight delivery, mariculture and aquaculture 2 gastritis diet òóò effective 4 mg doxazosin. Annual & Perennial Non-Timber Crops  Crops planted for food gastritis diet ìóëüòèêè doxazosin 4 mg, fodder gastritis diet ãîãëå order doxazosin 4mg mastercard, fiber gastritis diet ìàæîð 1 mg doxazosin for sale, fuel, or other uses Wood & Pulp Plantations  Stands of trees planted for timber or fiber outside natural forests, often with non-native species Livestock Farming & Ranching  Domestic terrestrial animals raised in one location on farmed or non-local resources (farming); also, domestic or semi-domesticated animals allowed to roam in the wild and supported by natural habitats (ranching) Marine & Freshwater Aquaculture  Aquatic animals raised in one location on farmed or nonlocal resources; also, hatchery fish allowed to swim in the wild 2. Energy Production & Mining  Threats from production of non-biological resources 3. Oil & Gas Drilling  Exploring for, developing, and producing petroleum and other liquid hydrocarbons Mining & Quarrying  Exploring for, developing, and producing minerals and rocks Renewable Energy  Exploring, developing, and producing renewable energy 4. Transportation & Service Corridors  Threats from long, narrow transport corridors and the vehicles that use them, including associated wildlife mortality 4. Biological Resource Use  Threats from consumptive use of "wild" biological resources, including both deliberate and unintentional harvesting effects; also, persecution or control of specific species 5. Hunting & Collecting Terrestrial Animals  Killing or trapping terrestrial wild animals for commercial, recreation, subsistence, research or cultural purposes, or for control/persecution reasons; includes accidental mortality/bycatch Gathering Terrestrial Plants  Harvesting plants, fungi, and other non-timber/non-animal products for commercial, recreation, subsistence, research or cultural purposes, or for control reasons Logging & Wood Harvesting  Harvesting trees and other woody vegetation for timber, fiber, or fuel Fishing & Harvesting Aquatic Resources  Harvesting aquatic wild animals or plants for commercial, recreation, subsistence, research, or cultural purposes, or for control/persecution reasons; includes accidental mortality/bycatch 5. Human Intrusions & Disturbance  Threats from human activities that alter, destroy and disturb habitats and species associated with non-consumptive uses of biological resources 6. Recreational Activities  People spending time in nature or traveling in vehicles outside established transport corridors, usually for recreational reasons War, Civil Unrest & Military Exercises  Actions by formal or paramilitary forces without a permanent footprint Work & Other Activities  People spending time in or traveling in natural environments for reasons other than recreation, military activities, or research 7. Natural System Modifications  Threats from actions that convert or degrade habitat in service of managing natural or semi-natural systems, often to improve human welfare 7. Fire & Fire Suppression  Suppression or increase in fire frequency and/or intensity outside its natural range of variation Dams & Water Management/Use  Changing water flow patterns from their natural range of variation, either deliberately or as a result of other activities 7. Other Ecosystem Modifications  Other actions that convert or degrade habitat in service of managing natural systems to improve human welfare 8. Invasive & Other Problematic Species & Genes  Threats from non-native and native plants, animals, pathogens/microbes, or genetic materials that have or are predicted to have harmful effects on biodiversity following their introduction, spread and/or increase in abundance 8. Invasive Non-Native/Alien Species  Harmful plants, animals, pathogens and other microbes not originally found within the ecosystem(s) in question and directly or indirectly introduced and spread into it by human activities Problematic Native Species  Harmful plants, animals, or pathogens and other microbes that are originally found within the ecosystem(s) in question, but have become out of balance or released directly or indirectly due to human activities Introduced Genetic Material  Human-altered or transported organisms or genes 8. Pollution  Threats from the introduction of exotic and/or excess materials or energy from point and non-point sources 9. Household Sewage & Urban Waste Water  Water-borne sewage and non-point runoff from housing and urban areas that include nutrients, toxic chemicals and/or sediments Industrial & Military Effluents - Water-borne pollutants from industrial and military sources, including mining, energy production, and other resource extraction industries that include nutrients, toxic chemicals and/or sediments Agricultural & Forestry Effluents  Water-borne pollutants from agricultural, silivicultural, and aquacultural systems that include nutrients, toxic chemicals and/or sediments, including the effects of these pollutants on the site where they are applied Garbage & Solid Waste  Rubbish and other solid materials, including those that entangle wildlife Air-Borne Pollutants  Atmospheric pollutants from point and non-point sources Excess Energy  Inputs of heat, sound, or light that disturb wildlife or ecosystems 9. Climate Change & Severe Weather  Direct threats from climatic changes that may be linked to global warming and other severe climatic or weather events that are outside the natural range of variation or can wipe out a vulnerable species or habitat 10. Droughts  Periods in which rainfall falls below the normal range of variation 10. Temperature Extremes  Periods in which temperatures exceed or go below the normal range of variation 10. Other Nonpoint source pollution from stormwater discharge threatens aquatic habitats. The broad category of "Pollution" with its six threat sub-categories was cited 646 times, amounting to 23 percent of all the identified threats. The "problematic native species" category was most commonly due to competition for resources or predation by human-subsidized predators like skunks and raccoons. More than a dozen invasive plant and animal species were identified as threats, and almost a quarter of these invasive species threats are pervasive, impacting more than 70 percent of the distribution of the native species. The four-toed salamander is the smallest salamander that occurs in New York State, measuring approximately 5 to 9 cm long. Commonly associated with sphagnum, this little salamander can be identified by having only four toes on its hind feet (other salamanders have five). One-hundred-thirty of the biological resource use threats are related to "fishing," mostly from by-catch or entanglement in fishing gear. Seventy-seven of these were related to renewable energy and included wind power development in upland areas of New York, as well as potential development of wind power off Long Island. Fifty-three of the energy production threats were related to oil and gas drilling, and included threats from hydraulic fracturing of shale to extract natural gas, as well as potential oil spills in marine waters. The primary highway-related threat noted is the effect of road salting, although direct vehicle strike and habitat fragmentation were also identified as threats in this category. Twenty-nine transportation threats were noted as the potential for vessel strikes in shipping lanes or spills resulting from the transport of oil. Fourteen of the transportation threats were related to service lines-either birds colliding with towers during flight or being electrocuted while perching on the towers. Forty-nine of these threats were related to crop agriculture, mostly intensification of agriculture from pasture/hay to row crops. Livestock farming threatens two species, and wood plantations and aquaculture each threaten only one species. The spread of invasive species threatens ponds, lakes, and rivers throughout New York. Residential & Commercial Development Housing & Urban Areas Commercial & Industrial Areas Tourism & Recreation Areas subtotals 2. Natural System Modifications Fire & Fire Suppression Dams & Water Management/Use Other Ecosystem Modifications subtotals 8. This is an indication that while the identified threats often have a broad geographic scope and some are occurring in all parts of the state, in most cases, the decline in the population of a species is not due to a single threat but is a result of the cumulative impacts of multiple threats. Agriculture & Aquaculture Annual & Perennial Non-Timber Crops Wood & Pulp Plantations Livestock Farming & Ranching Marine & Freshwater Aquaculture subtotals 3. Invasive & Other Problematic Species & Genes Invasive Non-Native/Alien Species Problematic Native Species Introduced Genetic Material subtotals 9. The scope and severity of 88 of the 2,829 identified threats was unknown, and these threats were excluded from the multiplied pairs analysis. The scope and severity measures that were identified by the taxonomic expert groups for the remaining 2,741 threats were converted to numeric values by assigning a value of 1 to 4, as follows: Scope 1 = Narrow (affecting 1-10% of the occupied area in New York) 2 = Restricted (affecting 11-30% of the occupied area in New York) 3 = Widespread (affecting 31-70% of the occupied area in New York) 4 = Pervasive (affecting 71-100% of the occupied area in New York) Severity 1 = Low (reduce/degrade population by 1-10%) 2 = Medium (reduce/degrade population by 11-30%) 3 = High (reduce/degrade population by 31-70%) 4 = Very High (reduce/degrade population by 71-100%) the scope and severity values for each threat were multiplied to derive a combined score in one of nine categories (1, 2, 3, 4, 6, 8, 9, 12, 16). This combined value provides a single measure of the impact of each threat, identifying the relative impact of each threat. Energy Production & Mining Oil & Gas Drilling Mining & Quarrying Renewable Energy subtotals 4. Transportation & Service Corridors Roads & Railroads Utility & Service Lines Shipping Lanes Flight Paths subtotals 5. Biological Resource Use Hunting & Collecting Terrestrial Animals Gathering Terrestrial Plants Logging & Wood Harvesting Fishing & Harvesting Aquatic Resources subtotals 6. Human Intrusions & Disturbance Recreational Activities War, Civil Unrest & Military Exercises Work & Other Activities subtotals 7. Pollution Household Sewage & Urban Waste Water Industrial & Military Effluents Agricultural & Forestry Effluents Garbage & Solid Waste Air-Borne Pollutants Excess Energy subtotals 10. This threat category includes housing and urban areas, commercial and industrial development, and recreation areas (marinas and ski resorts). Development of housing and urban areas was cited most frequently, followed by tourism and recreational areas, and then the frosted elfin is a state-threatened species, commercial and industrial development. The with population declines from habitat loss and fire difference between the number of times that suppression. Host plants for frosted elfin are wild residential development was identified as a indigo and lupine, which grow in sandy soil habitats threat, and the relatively few times that that experience frequent disturbance. Active commercial development was noted is likely management of these habitats is necessary to due to "suburban sprawl," where development maintain conditions favorable to the host plants. But more important than the relative number of threats identified in each sub-category of development is the overall threat of the cumulative effects of residential, commercial, and recreational development. As suburban sprawl occurs throughout New York, development degrades the ecological value of remaining natural habitat patches through habitat fragmentation. Effects of habitat fragmentation are loss of connectivity to patches of similar or complementary habitats, the creation of "sink" habitats in which meta-population dynamics are lost in isolated patches, increased susceptibility to predation from edge effects, and a reduction in the types of species the habitat can support. The effects of exurban development on wildlife in the Adirondack Park have been studied by the Wildlife Conservation Society. This work documented that the construction of houses and roads alters wildlife communities, increasing populations of predators and competitors that previously occurred in lower numbers. The combined effect of these changes tends to favor certain kinds of species over othersÂomnivores over insectivores, residents over migrants, generalists over habitat specialists (especially interior forest specialists), and tree nesters over ground nesters. Scarlet tanager is one example of a specialized interior forest-dwelling species that must compete with generalist species that use exurban development as habitat. Most of these threats were related to an intensification of agricultural activities, primarily the conversion of pasture and hay lands to row crops. The expansion of biofuels production has led to an increase in the amount of acreage in corn production. Most of this increase is a result of conversion of pasture lands, although some of this increased agriculture is a result of clearing forested lands. Sediment and nutrient runoff from agricultural operations impacts waterbodies in some areas of the state, and this impact was noted separately from threats from agricultural pesticides and nutrient runoff. Aquaculture is a relatively small industry in New York and was identified as a threat to only one marine fish species, cunner. Most of these threats are related to wind power development and the potential development of hydraulic fracturing in New York. Threats placed in the Renewable Energy sub-category were related to interactions with and habitat loss from both terrestrial and off-shore wind turbine projects. Whether turbines in New York have a population level-effect on birds (and potentially marine species if off-shore projects were approved) remains unknown. They are, however, the greatest threat to the tree bats (red, hoary, and silver-haired bat). This process requires construction of drilling pads, wastewater containment facilities, construction of roads, and pipelines to transport the extracted gas. These activities can be a threat to wildlife in multiple ways: pollution, habitat destruction, water withdrawals, the introduction of invasive species, and exacerbating climate change. Mining and quarrying was one of the less frequent threats to be noted, but where it was cited it impacted multiple species. Mining operations destroy eastern rat snake den habitats, while the activities often disturbed the basking sites of northern copperheads, and both the basking and den sites of timber rattlesnakes are affected. The eastern wormsnake is particularly affected by mining and excavation due to its fossorial (burrowing) nature. Changes in hydrology due to gravel and limestone mining threatens the habitat of watercress snail. It is a broad category which includes roads and railroads, utility and service lines, shipping lanes, and flight paths. Roads and railroads pose the greatest threat, which may be a factor of their prevalence on the landscape. Utility and service lines are another corridor-type development that is prevalent throughout the state. The Karner blue butterfly, for instance, will use utility and service lines if lupine is present, and occasionally as a corridor to travel between patches and colonize new areas. Birds may ingest road salt crystals for grit, and consumption of even small amounts of salt can result in toxicosis and death for birds. Wildlife such as moose are also attracted to the roadway to ingest salt crystals, which leads to higher incidents of vehicular accidents and road kills. Road salt can also cause a decline among populations of salt-sensitive species in the freshwater aquatic environment. Damage to vegetation can have significant impact on wildlife habitat by destroying food resources, shelter and breeding and nesting sites, and by creating a favorable environment for non-native invasive species. Aquatic species impacted include fish, macro-invertebrates, insects, and amphibians. It was cited as a threat to 32 amphibians and reptiles, often widespread in scope. It is also a threat to some birds, especially raptors, and an identified threat to the least weasel and New England cottontail. New York has an extensive road network and statewide has the tenth-highest road density in the United States. In addition to the high density of roads, high traffic volume increases the likelihood that an animal seeking to cross the road will be unsuccessful or be struck by a vehicle. Large birds of prey, with their broad wingspan and propensity for perching on high structures, are especially susceptible and have the greatest incidence of electrocution. Scientists with the Bioacoustics Research Program at the Cornell Lab of Ornithology have captured the sounds of three whale species in the eastern hog-nosed snake occurs in open the waters around New York City: the woodlands or pine barrens that provide the sandy humpback, fin and North Atlantic right whale. In County, New York, though populations are known addition to the hazard to marine life of being farther north in southern Ontario. Long-term trends, struck by a vessel, there is concern that the especially in northern portions of the range, noise from large ships can impact whale suggest declines due to loss of habitat, road mortality, and human intervention, but most communication and impair critical behaviors. Once heavily polluted, the restoration of Jamaica Bay over the last 40 years has led to an increase in the viability and variety of the species of wildlife that live there. The National Park Service, which oversees Jamaica Bay as part of the Gateway National Recreation Area, identifies the area as significant habitat. A colony of 15 pairs of laughing gulls was observed nesting at Jamaica Bay in 1979. Biological Resource Use Use of biological resources through recreational hunting and fishing is common throughout New York. These activities are regulated by licensing, length of open season, bag limits, type of implement allowed, and minimum size requirements. Commercial fishing occurs primarily in marine waters and is also closely regulated to conserve the resource. Legal, regulated hunting and fishing are carefully managed to ensure sustainable use.
Transmission is generally by ingestion of an infective stage of the parasite or by insect bite gastritis vs ulcer generic doxazosin 4 mg without a prescription. They are divided into three main groups: tapeworms (cestodes) gastritis symptoms in telugu cheap doxazosin 1mg otc, flukes (trematodes) chronic gastritis stress generic doxazosin 2 mg with mastercard, and roundworms (nematodes) gastritis otc discount doxazosin 1 mg. Helminths are parasitic gastritis diet popcorn discount doxazosin 2mg overnight delivery, receiving nutrients by ingesting or absorbing digestive contents gastritis diet ñèíîïòèê generic doxazosin 2mg with mastercard, or ingesting or absorbing body fluids or tissues. All major groups of helminths can cause disease in humans, as described in Chapter 22, p. A virus may also have an envelope derived from the plasma membrane of the host cell from which the virus is released. The fate of the host cell following viral infection ranges from rapid lysis releasing many progeny virions, to gradual, prolonged release of viral particles. In addition, it is helpful if these relationships can be visualized, using a consistent color-coding system. To this end, the authors have adopted several graphic formats that are used throughout this book. Hierarchical organization the first is a hierarchical organization that resembles a family tree (Figures 1. These graphs provide a summary of the major characteristics of a particular microorganism. For example, tracing the lineage of staphylococci reveals that they have rigid cell walls and are simple, unicellular, free-living organisms that are gram-positive cocci. Pie chart organization: bacteria and viruses A second, simpler format represents selected groups of bacteria or viruses as wedges of a pie chart. These pie charts focus on the most important defining characteristics of a particular organism. For example, bacteria are organized into eight groups according to Gram staining, morphology, and biochemical or other characteristics. The ninth section of the bacterial pie chart, labeled "Other", is used to represent any organism not included in one of the other eight categories (Figure 1. In a similar way, viral pathogens are organized into seven groups based on the nature of their genome, symmetry of organization, and the presence or absence of a lipid envelope (Figure 1. Taxonomy this book uses a taxonomic hierarchy for the classification of bacteria, fungi, protozoans, and helminths. The first letter of the genus name is always capitalized, and the species name begins with a lower case letter. Introduction to Microbiology Medically Important Bacteria Lacking cell walls Rigid cell walls Flexible (Spirochetes) Filamentous Simple unicellular Obligate intracellular parasite Free-living Gram-positive Gram-negative Cocci Rods Cocci Nonenteric rods Enteric rods Figure 1. A healthy newborn enters the world in essentially sterile condition, but, after birth, it rapidly acquires normal flora from food and the environment, including from other humans. The species contained in normal flora cannot be rigidly defined for all humans, because those species vary from individual to individual, as a result of physiologic differences, diet, age, and geographic habitat. It is useful to be aware of the normal types and distribution of resident flora, because such knowledge provides an understanding of the possible infections that result from injury to a particular body site, and places in perspective the possible sources and significance of microorganisms isolated from the site of an infection. Skin Skin can acquire any bacteria that happen to be in the immediate environment, but this transient flora either dies or is removable by washing (Figure 2. The skin surface does not provide a favorable environment for colonization by microorganisms; for example, it is Figure 2. Normal Flora generally dry (moist regions of the skin are more conducive to bacterial growth than dry regions), it has a slightly acidic pH, and the sweat glands produce a liquid containing a high concentration of sodium chloride that causes a hyperosmotic environment on the skin surface. Nevertheless, the skin supports a permanent bacterial population (resident flora), residing in multiple layers of the skin (see Figure 2. Most common among the skin colonizers (103 to 104 per cm2) are aerobic Staphylococcus epidermidis and other coagulase-negative staphylococci (see p. Anaerobic organisms, such as Propionibacterium acnes, reside in deeper skin layers, hair follicles, and sweat and sebaceous glands. Other organisms that normally inhabit the skin are also present, but at a lower frequency (Figure 2. Tears, which contain the antimicrobial enzyme lysozyme, help limit the bacterial population of the conjunctiva. Mouth and nose Gram (+) cocci Staphylococcus aureus Staphylococcus epidermidis Streptococcus species Gram (+) bacilli Corynebacterium species Propionibacterium acnes Gram (Â) cocci Moraxella Neisseria species Tears, which contain the antimicrobial enzyme lysozyme, help limit the bacterial population of the conjunctiva. The mouth and nose harbor many microorganisms, both aerobic and anaerobic (Figure 2. In addition, the teeth and surrounding gingival tissue are colonized by their own particular species, such as Streptococcus mutans. Anaerobic organisms Bacteroides species Fusobacterium Lactobacillus species Prevotella species Gram (Â) cocci Neisseria species Gram (Â) rods Haemophilus species Figure 2. Beneficial Functions of Normal Flora pharynx of many healthy individuals, can cause acute bacterial pneumonia, especially in the aged and those whose resistance is impaired. Intestinal tract In an adult, the density of microorganisms in the stomach is relatively low (103 to 105 per gram of contents) due to gastric enzymes and acidic pH. The density of organisms increases along the alimentary canal, reaching 108 to 1010 bacteria per gram of contents in the ileum, and 1011 per gram of contents in the large intestine. Some twenty percent of the fecal mass consists of many different species of bacteria, more than 99 percent of which are anaerobes (Figure 2. Bacterioides species constitute a significant percentage of bacteria in the large intestine. Urogenital tract the low pH of the adult vagina is maintained by the presence of Lactobacillus species, which are the primary components of normal flora. If the lactobacillus population in the vagina is decreased, for example, by antibiotic therapy, the pH rises and potential pathogens can overgrow. The most common example of such overgrowth is the yeast-like fungus, Candida albicans (see p. The urine in the kidney and bladder is sterile, but can become contaminated in the lower urethra by the same organisms that inhabit the outer layer of the skin and perineum (Figure 2. Bacteriodes fragilis causes intraabdominal abscesses, and additional intestinal bacteria commonly cause peritonitis following appendicitis, diverticulitis, or other trauma resulting in perforation of the intestine. First, the sheer number of harmless bacteria in the lower bowel and mouth make it unlikely that, in a healthy person, an invading pathogen could compete for nutrients and receptor sites. Second, some bacteria of the bowel produce antimicrobial substances to which the producers themselves are immune. Third, bacterial colonization of a newborn infant acts as a powerful stimulus for the development of the immune system. Fourth, bacteria of the gut provide important nutrients, such as vitamin K, and aid in digestion and absorption of nutrients. For example, when normal bowel flora is depleted by antibiotic therapy leading to overgrowth by the resistant C. A well-known example is the conversion by bacterial sulfatases of the sweetener cyclamate into the bladder carcinogen cyclohexamine. Typhoid fever is an example of a disease that can be acquired from a carrier (see p. Lactobacilli produce acid that, in turn, inhibits the growth of potential pathogenic bacteria and fungi. Antibiotic therapy can reduce normal flora in the bowel, allowing pathogenic organisms normally present in low numbers to overgrow. Some microorganisms are unequivocally pathogenic, whereas others (the majority) are generally harmless. Further, some pathogens cause disease only under certain conditions (for example, being introduced into a normally sterile body site, or infection of an immunocompromised host). This chapter considers factors that influence whether a microorganism is a pathogen. Pathogenicity of a microorganism depends on its success in completing some or all of these stages. Virulence factors Virulence factors are those characteristics of a bacterium that enhance its pathogenicity, that is, the ability to cause disease. Once entry is achieved, the pathogen must overcome a diversity of host defenses before it can establish itself. These include phagocytosis, the acidic environments of the stomach and urogenital tract, and various hydrolytic and proteolytic enzymes found in the saliva, stomach, and small intestine. Pathogenicity of Microorganisms saccharide capsule (for example, Streptococcus pneumoniae and Neisseria meningitidis) have a better chance of surviving these primary host defenses. Adherence to host cells: Some bacteria (for example, Escherichia A Fimbrial (Pilus) Adhesion Pili (fimbriae) Glycolipid Host cell membrane Glycoprotein coli, see p. Other bacteria have cell surface adhesion molecules or particularly hydrophobic cell walls that allow them to adhere to the host cell membrane (Figure 3. A striking example of the importance of adhesion is that of Neisseria gonorrhoeae in which strains that lack pili are not pathogenic (see p. Invasiveness: Invasive bacteria are those that can enter host cells B Afimbrial Adhesion Cell Wall Cell surface adhesion molecule or penetrate mucosal surfaces, spreading from the initial site of infection. Invasiveness is facilitated by several bacterial enzymes, the most notable of which are collagenase and hyaluronidase. These enzymes degrade components of the extracellular matrix, providing the bacteria with easier access to host cell surfaces. Invasion is followed by inflammation, which can be either pyogenic (involving pus formation) or granulomatous (having nodular inflammatory lesions), depending on the organism. C Hydrophobic Adhesion Cell Wall the pus of pyogenic inflammations contains mostly neutrophils, whereas granulomatous lesions contain fibroblasts, lymphocytes, and macrophages. Bacterial toxins: Some bacteria cause disease by producing tox- ins, of which there are two general types: the exotoxins and the endotoxins. Exotoxins, which are proteins, are secreted by both gram-positive and gram-negative bacteria. In contrast, endotoxins, which are lipopolysaccharides, are not secreted, but instead are integral components of the cell walls of gram-negative bacteria. Exotoxins: these include some of the most poisonous sub- Hydrophobic interaction between bacterial cell wall and host cell membrane Figure 3. It is estimated that as little as one microgram of tetanus exotoxin can kill an adult human. Bacterial Pathogenesis 13 rapidly inactivated by moderate heating (60oC), notable exceptions being staphylococcal enterotoxin and E. In addition, treatment with dilute formaldehyde destroys the toxic activity of most exotoxins but does not affect their antigenicity. Formaldehyde-inactivated toxins, called toxoids, are useful in preparing vaccines (see p. Exotoxin proteins are, in many cases, encoded by genes carried on plasmids or temperate bacteriophages. An example is the diphtheria exotoxin that is encoded by the Tox gene of a temperate bacteriophage that can lysogenize Corynebacterium diphtheriae. These effects are produced indirectly by activation of macrophages, with the release of cytokines, activation of complement, and activation of the coagulation cascade. One important evasive strategy for the pathogen is to change its surface antigens. One mechanism, called phase variation, is the genetically reversible ability of certain bacteria to turn off and turn on the expression of genes coding for surface antigens. In this manner, the expressed surface antigen can assume many different antigenic structures (see Figure 11. Pathogenicity of Microorganisms If a particular microorganism is isolated from infected tissue (for example, a necrotic skin lesion), one cannot conclude that the isolated organism caused the lesion. The organism could, for example, be a harmless member of the normal skin flora (see p. Alternatively, the organism may not be a natural resident of the skin, but an opportunistic pathogen that secondarily infected the necrotic lesion. Infections in human populations Bacterial diseases may be communicable from person-to-person or noncommunicable. For example, cholera is highly communicable (the disease-causing organism, Vibrio cholerae, is easily spread), whereas botulism is noncommunicable because only those people who ingest the botulinum exotoxin are affected. Highly communicable diseases, such as cholera, are said to be contagious, and tend to occur as localized epidemics in which the disease frequency is higher than normal. Pandemics, such as the 1918 influenza pandemic, arise because the human population has never been exposed to , and, thus, has no immunity against, the specific strain of influenza virus. Sick 3 the isolated microorganism must cause the original disease when inoculated into a susceptible animal. Consequently, the first pathogenic manifestations of viral infection are seen at the cellular level. The course of events following initial exposure to some viruses may include rapid onset of observable symptoms, which is referred to as an acute infection. Alternatively, the initial infection by other viruses may be mild or asymptomatic. Following the initial infection, the most common outcome is that the virus is cleared completely from the body by the immune system. For some viruses the initial infection is followed by either a persistent infection or a latent infection. Viral pathogenesis at the cellular level Cells show a variety of different responses to viral infection, depending on the cell type and virus. Many viral infections cause no apparent morphologic or functional changes in the cell. When changes do occur, several (potentially overlapping) responses can be recognized (Figure 3. Dead or dying cells release a brood of progeny viruses that repeat the replication process.
