What is Disease: Definition and 135 Discussions

A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not due to any immediate external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms. A disease may be caused by external factors such as pathogens or by internal dysfunctions. For example, internal dysfunctions of the immune system can produce a variety of different diseases, including various forms of immunodeficiency, hypersensitivity, allergies and autoimmune disorders.
In humans, disease is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person afflicted, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories. Diseases can affect people not only physically, but also mentally, as contracting and living with a disease can alter the affected person's perspective on life.
Death due to disease is called death by natural causes. There are four main types of disease: infectious diseases, deficiency diseases, hereditary diseases (including both genetic diseases and non-genetic hereditary diseases), and physiological diseases. Diseases can also be classified in other ways, such as communicable versus non-communicable diseases. The deadliest diseases in humans are coronary artery disease (blood flow obstruction), followed by cerebrovascular disease and lower respiratory infections. In developed countries, the diseases that cause the most sickness overall are neuropsychiatric conditions, such as depression and anxiety.
The study of disease is called pathology, which includes the study of etiology, or cause.

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  1. Astronuc

    Rare Disease in Yorkshire, England: A Case Study

    I've never heard of this rare disease/illness. I just learned about it from a news feed from a case in Yorkshire, England. https://www.manchestereveningnews.co.uk/news/uk-news/man-30-died-suddenly-after-25915295 https://www.frontiersin.org/articles/10.3389/fimmu.2021.773352/full It's...
  2. S

    Biology Huntington Disease Pedigree Problem

    The first picture is the image given in the question, and the second picture is the possible genotypes given in the solution manual. How is it possible that person II.1 (first male in the second generation) has the genotype A/- when he is unaffected? I thought that because person II.1 and...
  3. Astronuc

    Tanzania, Deadly outbreak, unknown disease (Ebola-like, hemorrhagic virus?)

    https://abcnews.go.com/International/tanzania-investigates-deadly-outbreak-mystery-disease/story?id=86870310 https://www.ndtv.com/world-news/mysterious-ebola-like-disease-kills-3-in-tanzania-probe-launched-3158007 The outbreak in Tanzania comes days after Ghana reported two suspected cases of...
  4. berkeman

    Medical Promising Results: Stanford's Vibrating Glove Treats Parkinson's Disease

    I saw this on the local TV news tonight (I live in Silicon Valley not far from Stanford). It looks to be a very promising and innovative treatment for Parkinson's Disease that is showing some amazing early results (led by Stanford Medicine researcher Peter Tass, MD, PhD). They are calling for...
  5. nomadreid

    Heme iron and cardiovascular disease

    In the "Results" section of the Abstract of https://pubmed.ncbi.nlm.nih.gov/23708150/, (due to a paywall, I get no further) there is the following "The dose-response RR of CHD for an increase in heme iron intake of 1 mg/day was 1.27" (CHD being coronary heart disease). Is the paraphrasing in...
  6. Astronuc

    Meningococcal purpura fulminan disease (type of food poisoning)

    A teen ate leftover rice and noodles. Hours later, doctors amputated his legs and fingers https://www.usatoday.com/story/news/health/2022/02/22/leftover-food-disease-amputated-legs-fingers/6890754001/ The article later mentions bacterium . . ...
  7. Astronuc

    Current disease events in wildlife and domestic animals

    My wife read an article last night about an outbreak of hemorrhagic fever in rabbits, and it has been passing through populations throughout the US. So, I decided to look into it and came across a wildlifehealth.org. There is a lot of nasty stuff out there. Detection of High Pathogenic Avian...
  8. JonMoulton

    "Can Oligonucleotides Target RNA Splicing to Treat Disease?" from OTS

    From the Oligonucleotide Therapeutics Society: "Can Oligonucleotides Target RNA Splicing to Treat Disease?" https://www.oligotherapeutics.org/can-oligonucleotides-target-rna-splicing-to-treat-disease/
  9. K

    Could someone age without any chronic disease?

    Could someone age and get old without any chronic disease, even the most common diseases like diabetes, heart attack, high blood pressure, etc... not including hair loss, presbyopia, or any disease that is temporary and can heal completely Is it possible to achieve this by change in lifestyle...
  10. C

    Fetal Origins of Adult Disease

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4608552/ Do you think this is already 100% accepted by the medical and scientific world? It says that if you are born Small for Gestational Age. You would get all kinds of diseases like diabetes, hypertension, coronary diseases, mental diseases etc...
  11. Astronuc

    Zoonotic disease: Buruli ulcer

    NY Times - A Terrifying Disease Stalks Seaside Australia: Flesh-Eating Ulcers https://news.yahoo.com/terrifying-disease-stalks-seaside-australia-120741684.html What looked like a sunburn on the top of a man's foot turned out to be an infection of a species of flesh-eating bacteria! The species...
  12. B

    Bayes' theorem and disease prevalence

    Hello at all! I have to solve this exercise: A tampon diagnostic test provides 1% positive results. The positive predictive values (probabilities of positive test disease) and negative (absence disease given negative test) are respectively 0.95 and 0.98. What is the prevalence of the disease...
  13. Astronuc

    Mortality from heart disease, winter effect

    I came across one article, and I've been looking for similar articles for other nations or groups, e.g., EU. Mortality from heart disease apparently spikes around Winter Solstice and Christmas (end of the calendar year), as well as other causes, which may be related, e.g., obesity and diabetes...
  14. A

    COVID Question on initial viral load and disease progression of Covid-19

    What is the rate of Covid-19 infection compared to the rate of immune response? Faster, slower? Consider two scenarios: Scenario 1: Small initial exposure to Covid-19. Person is briefly exposed to Covid. They perhaps touch infected surface and touch inside of their nose. Scenario 2...
  15. jim mcnamara

    EPA and DHA Heart Disease study

    “Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials” by Aldo A. Bernasconi, PhD; Michelle M. Wiest, PhD; Carl J. Lavie, MD; Richard V. Milani, MD; and Jari A. Laukkanen, MD, PhD, 17 September 2020, Mayo Clinic Proceedings...
  16. Evo

    Corona virus, no longer considered just a respiratory disease

    This has come up in the press the last few days that they now believe Covid-19 is not just a respiratory disease. This is a very interesting article on it. It explains the virus and how it works. https://www.ucsf.edu/magazine/covid-body
  17. T

    New Blood Test for Alzheimer Disease

    The Journal of the American Medical Association (JAMA) today (7/28/2020) published an article on using presence of phospho-tau217 (p-tau217) in blood plasma to detect Alzheimers Disease. Over 80% specificity, and early results look like it could be predictive up to 20 years...
  18. mktsgm

    Medical Necrosis vs Apoptosis: Exploring Disease Implications

    It is said that necrosis precipitates inflammation. It is also considered that inflammation causes most of the damage in any diseased condition. Comparatively, apoptosis doesn't trigger inflammation. I have the following doubts in this context. 1) Is necrotic (and/or apoptotic) cell death...
  19. G

    I Solving a DE for modelling the spread of an infectious disease

    This DE is related to a mathematical model of the spread of an infectious disease: $$f'\left(x\right)=a\cdot\left[f\left(x\right)-f\left(x-b\right)\right]$$ where a and b are positive constants. I would like some pointers as to how I should begin attempting to solve it.
  20. G

    I Solving the Paradox: A Dynamical Model of Disease Spread

    I'm considering a dynamical model of the scenario of a disease spreading across the population, modelling the number of cases, and there's a mathematical puzzle which I'd like to solve. It's kinda different from the S-I-R model, and its also a crude model. First, we consider two numbers, NT...
  21. G

    I Evaluating Accuracy of Dynamic Model for Spreading Disease

    I'm trying to dynamically model the scenario of a disease spreading across the population, modelling the number of cases, and I would love to hear your feedback. It's kinda different from the S-I-R model, and its also a crude model. First, we consider two numbers, NT and NA. NT is the total...
  22. L

    MHB Probability of Having a Disease

    According to the CDC 1 out of 102 persons who are males of a particular demographic have HIV. That mean's there is 1/102 = .98 * 100 = 1% chance of having HIV. There is a swab HIV test available that is 91.7% accurate at being able to identify HIV positive people. This means that 12 out of 13...
  23. callie123

    Can an immune person be the key to finding the cure to a disease?

    Hey, I'm writing a science-fiction novel, and trying to keep as much "sci" in there as I can! Scenario: A character has been successfully cured of a deadly disease, using cool (insert hand wave) stuff. But all records of the cure have been destroyed (files of info, samples, etc). Now the...
  24. C

    Question about mutations and disease

    I'm hoping a mod can move this to the biology forum section, I keep trying to post in it, but every time I click on the biology forums I'm automatically logged out. I've read about how sometimes the DNA polymerase inserts a wrong amino acid and ends up modifying the DNA rather than the RNA...
  25. Natuurfenomeen22

    Any Australian Studies on Canine vWD Available?

    Hello people, For a project I am working on I am looking for more detailed information on clinical issues that may arise in vWD in dogs. The focus for us is on a specific breed of dogs, but first we need some data from different breeds to have a benchmark. Does anyone here happen to know...
  26. K

    What is the weight of genetics in preventing disease

    Is there any research or study which is to estimate the weight of genetics in preventing one or more diseases compared to other factors? A lot of time, for example, explaining how a particular kind of cancer occurs in someone, genetics is often mentioned, in addition to other factors, but how...
  27. BillTre

    Polio-like Disease Strikes Children

    A Science mag news article describes a rare disease (acute flaccid myelitis) that can cause Polio-like symptoms has been found in 22 of the US states. It may (or may not) be due to the enterovirus D68 (EV-D68), a polio relative. The virus is thought to normally cause mild flu symptoms, but its...
  28. Kunal Aggarwal

    Biomarkers for Alzheimer's disease in sMRI?

    I have been looking for biomarkers for Alzheimer's disease which can be detected in structural MRI. I have gone through some papers and found that Gray matter, white matter and CSF are good biomarkers. But is there any other except?
  29. B

    I Odds of dying of the same disease on the same date as another....

    Recently, John McCain died of glioblastoma (brain cancer.) The odds of dying on particular date is 1 in 365. He died of the same disease as did Ted Kennedy, on the very same date that Kennedy did. Glioblastoma affects 3.1 in 100,000 population. The mean average life span living with the...
  30. K

    Still's disease and muscle movement

    What muscle or tendon is involved when you tried to touch the armpit of the other side of the body and there is slight muscle or tendon pain for the arms that reached out to the other armpit ? I feel some mild muscle pain last night after gym and just want to see the anatomy involved. I'm not...
  31. D

    How does corrective treatment of lymphedema help lymph flow?

    Homework Statement Produce an detailed understandsing of the anatomy and function of the lymphatic system, using correct scientific terminology to explain the rationale for use of corrective treatment for lymphedema. Homework Equations N/A The Attempt at a Solution Lymphatic edema is the...
  32. D

    How does Hodgkin's lymphoma affect the lymphatic system?

    Homework Statement How does Hodgkin's lymphoma effect the "normal" function of the lymphatic system? Homework Equations N/A The Attempt at a Solution After research I have found out that HL casues lymph nodes to become inflames. I have concluded HL causes lymph fluid to get blocked at lymph...
  33. J

    If Stephen Hawking didn't have the disease that he had....

    How do you think Stephen Hawking would have been if he didn't have the disease that he had and wasn't physically handicapped?
  34. M

    MHB Probability that someone has the disease

    Hey! :o The percentage of people that have a disease A is $0,01$. We apply twice a test for that disease, each of which give the correct answer with probability $0,95$. What is the probability that someone has that disease if at least one test is positive and what is the probability if both...
  35. T

    Medical Can Sitting for Long Hours Lead to Permanent Health Problems?

    I have been sitting in front of a computer for more than 10 hours/day for about three years. I feel considerable pain in my arms and legs all the time, although they appear more serious during the night. The medical recommendation is to do exercises. My question is, if I exercise myself from now...
  36. jim mcnamara

    Alzheimers disease and glycolysis

    NIH news release: https://www.nih.gov/news-events/news-releases/higher-brain-glucose-levels-may-mean-more-severe-alzheimers To start with, this does NOT prove a link between glucose blood levels and Alzheimers onset. Or more simply put, this paper does not say: sugar causes Alzheimers. Why...
  37. A

    Studying How to pull myself together when facing disease, burnout, depression and more?

    Sorry for being annoying, but I am a student of physics for a month now. I started really well by setting up super good work habbits but all was ruined in a day when I was arguing with my parents about my treatment for my desiese. Since then everything has been hell, I fell behind bad, I am...
  38. jim mcnamara

    Macro nutrients balance and heart disease

    From meeting of cardiologists in Spain: Study on +135000 people worldwide, researchers interpretation: Note that the study included many residents of third world countries where macronutrient (fats and carbohydrates) over consumption is not common. For biology types...
  39. caters

    Medical Why can't appendicitis be treated with just antibiotics?

    I started having appendicitis 3 nights ago. It woke me up from sleep with lots of pain and nausea. I took pepto-bismol for the nausea but despite the fact that it had salicylic acid which is the prodrug of aspirin and releives pain by affecting genetic expression of the COX enzyme that forms...
  40. jim mcnamara

    Saturated dairy fat consumption and heart disease

    https://link.springer.com/article/10.1007/s10654-017-0243-1 Jung Huo et al, 2017 European Journal of Epidemiology, 'Milk and dairy consumption and risk of cardiovascular diseases and all-cause mortality: dose–response meta-analysis of prospective cohort studies' The takeaway is that saturated...
  41. Evo

    You Shouldn’t Go Gluten-Free Unless You Have Celiac Disease

    The links to the studies are in the article. Those with celiac disease often follow strict gluten-free diets, because consuming the protein found in wheat, rye, and barley can cause them to develop health problems and gastrointestinal issues. And yet, certain people seeking to lose weight have...
  42. wolram

    Medical Chagas Disease: A Hidden Threat to Latin Americans?

    This is a disease I have not heard of, and it seems not many Americans are aware of it, It seems it causes heart failure in many Latin Americans. https://www.sciencedaily.com/releases/2015/09/150909132742.htm As it may not be detected by medical staff and it seems not many are aware of it...
  43. gilakmesum

    Evidence that marijuana can cure cancer or Parkinson's disease?

    present time we just knew that US Government legalized the use of marijuana cigarettes. Is there any proven that marijuana can heal parkinson disease and also can heal cancer.
  44. mktsgm

    Medical Cause of Gastric reflux disease

    People generally associate Gastroesophageal reflux disease (GERD) with excessive production of hydrochloric acid in the stomach. We know that HCL is essential for proper digestion. In acid reflux the acid comes up the esophagus from the stomach due to the insufficiency of esophageal sphincter...
  45. hsdrop

    Medical What Causes Crohn's Disease and How Can We Understand It?

    this is something I was born with or at least it was affecting me by the time i was 3-6 years of age. I am almost 40 now and I still have no idea what causes crohn's. I know it an autoimmune thing (and yes I know what that means) but what cause it to happen? why does my body hate it self so...
  46. Sentosa

    How can natural selection be true if disease is inherited?

    I just finishedOn the Origin of Species. It seems Darwin is saying that characteristics that make it less likely for an organism to survive will drop out over time. But other scientists tell me that cancer has a genetic link, that suicide has a genetic predisposition, etc. Many diseases have...
  47. S

    Why is resection of tumor not done in metastatic disease?

    Hello everyone, Let's take a woman with a breast lump for example and it is malignant. I know that stage 3 and 4 disease, eg advanced/metastatic disease treatment is chemotherapy/radiotherapy. Then after it is downgraded they surgically resect the lump (stage 1 and 2). While this makes sense my...
  48. ShayanJ

    Alzheimer's disease in neural networks

    After watching "Still Alice"(starring Juliane Moore) which is about an Alzheimer's patient, I started thinking about this disease a little bit and suddenly it occurred to me that its plausible to expect seeing such an effect in neural networks too. I mean, imagine you have a neural network that...
  49. G

    Ebola Virus Disease: Mechanism of infection

    I have looked in a lot of different websites for a explanation of the mechanism of the ebolavirus to infect our body: how it avoid our immunology system, what it exactly change from our DNA and the consequences in the body. I didn't found a clear information, can someone help me to understand ebola?