The study of diseases, including their causes and effects.

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How to Determine Sufficient Time for Melanoma Survivor to Be Considered Low Risk?

Regarding melanoma, how do we determine the minimum amount of time that a patient is disease free for them to be considered low risk? We are attempting to do survival analysis on RNASeq data from ...
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20 views

What is meant by clinical progression? [closed]

What do the terms 'clinical progression' and 'disease progression' mean? Are they different from each other?
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30 views

What can saliva tell about ones health? [closed]

I was wondering if I d want to analyze something related to my current health based on my saliva. What could it be? I mean e.g. by putting a thermometer in your mouth you can know your body ...
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Question related to pathogen population [closed]

Does only one pathogen of one species enter the host and cause harm to the host or is a certain number of pathogen populations of the same species needed inside the host to disrupt the functionality ...
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1answer
30 views

Quantity of toxin release by pathogen in host

I came across these lines from this paper: Pathogenic microbes exert a broader sphere of influence by releasing a bolus of toxin that can act upon many cells within a given tissue and/or diffuse ...
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1answer
19 views

Which diagram correctly describe an effect of tar entering lungs?

Which flow diagram correctly describes the effect of tar entering lungs? Tar is a cause of Chronic obstructive pulmonary disease (COPD) which includes both chronic bronchitis and emphysema and it ...
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34 views

What negative effects does cannabalism have in other species (like prion diseases) and how are they mitigated?

It is well known that human cannibals are likely to suffer from a variety of ailments, particularly prion diseases. However a great many other species, from insect to ape practice cannibalism at much ...
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49 views

Geographical distribution of malaria and tuberculosis

Unlike malaria, tuberculosis (TB) is found across the whole world. Why and explain? I mean why are people affected with TB more than malaria and some say that in cold and developed countries malaria ...
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45 views

How do prions transmit their conformation to other proteins?

I was reading about prions and many sources say something to this effect: "Prions may propagate by transmitting their misfolded protein state: When a prion enters a healthy organism, it induces ...
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1answer
26 views

What is the reason for 'microcytic' anaemia?

I know the causes for microcytic anaemia are Fe deficiency, prolonged inflammation, Thalessemia, Sideroblastic etc. All these logically point to a decrease in Haemoglobin synthesis - either Haeme or ...
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45 views

Why aren't we immune to the “cold” [duplicate]

As far as I know, people suffer from the cold since ever. Why didn't and don't we evolve to resist it?
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Can the restless leg syndrome may have been caused due to natural selection? [closed]

Disclaimer: I don't know how much restless the leg has to be, in order to be considered a syndrome. RLS runs not only in my family but also several people in the locality. My hypothesis is that RLS ...
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61 views

Why might dogs get sick less frequently than their owners?

An article I was reading cited this study result "A comparison of 2473 pairs of dogs and their owners found that dogs were about 50 per cent less likely to have had two or more acute illnesses in the ...
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Is diarrhoea advantageous to the microbe?

Diarrhoea is a common side effect of many feco-orally transmitted bacterial infections. How does diarrhoea help the pathogen? Should it not have a selective evolutionary advantage? Do all symptoms of ...
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Why doesn't the Tsetse fly wipe out all animal life in its range?

The Tsetse fly, which is native to interior West Africa, carries the protozoan that causes sleeping sickness, a disease which was apparently invariably fatal before the advent of modern medications. ...
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Why doesn't blood remain on a mosquito's proboscis in quantities that could spread blood-borne diseases?

We know that HIV can't be transmitted by mosquitos, and nor can other highly virulent viruses that are transmitted through blood and bodily fluid exchanges, such as Ebola (thankfully!). Marcus Junius ...
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Can HIV be transmitted via mosquitos?

It is known that HIV is usually transmitted by direct blood or body fluid contact between an infected individual and a healthy person (like blood transfusion or needle sharing): Suppose a mosquito ...
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Grouping OMIM disease codes

I have ~100 sets of genes, and each set includes between 2 and 70 genes. I'd like to perform an enrichment analysis on each of these sets to test if they're enriched for OMIM disease labels. However, ...
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156 views

What is the difference between AIDS and SCID? [closed]

AIDS acquired immune deficiency syndrome According to wikipedia, Caused by infection with the human immunodeficiency virus (HIV).Following initial infection, a person may not notice any ...
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Do plant and animal bacterial pathogen differ too much?

I will be involved in a plant disease produced by a bacterial pathogen, Acidovorax citrulli. I've previously worked with animal pathogens such as Haemophilus parasuis. Are there any big differences ...
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44 views

What is effect of sperm in blood?

Staphylococcus aureus, Streptococcus pyogenes, and Clostridium perfringens all produce hyaluronidase. Each of these bacteria are pathogens (use hyaluronidase as a virulence factor to destroy the ...
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Why do kupffer cells not attack sporozoites of malaria?

During malaria, why don't kuppfer cells (hepatic macrophages) attack the plasmodium and stop schizogony, thus saving us from the disease?
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78 views

How would the immune system respond to antigens and food poisoning?

QUESTION: How does this information explain the likelihood of a more violent response in someone who has already had food poisoning caused by salmonella bacteria WHAT I KNOW: In the first exposure, ...
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1answer
72 views

Explanation of the ‘cherry red spot' in Tay Sachs disease

In Tay Sachs disease, a hallmark symptom is a cherry red spot in the macula of the eye surrounded by a halo of white. I understand that the ganglion cells, which are higher in numbers around the ...
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1answer
30 views

Why are vegetations in Infective endocarditis common on the atrial side?

Robbin's Pathology says that vegetations of IE are more common on the atrial side in AV valves. In Liebmann Sack's Endocarditis, which is a sterile (non bacterial) type of endocarditis, the underside ...
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456 views

Why is the species-diversity of deadly parasites greatest in the tropics?

There are so many parasites living in tropical regions of Africa, South America, or Asia, but very few in Europe or North America. Is this due to climate, or are there other reasons? Many of the ...
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What causes the range of severity of neurological deficits in Down's syndrome?

It's known that the severity of symptoms caused by a trisomy 21 varies from individual to individual. Part of the explanation for this range of severity is the finding that 94% of Down's syndrome ...
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49 views

What is meningitis? [closed]

I know that meningitis is the inflammation of the meninges surrounding the brain and the spinal cord. But I still don't understand this definition. If you can broaden the definition, please do.
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37 views

Does sickle cell anaemia protect a victim against malaria? [duplicate]

My biology textbook says that a person with sickle cell anaemia is less prone to malaria. Why is that so? I'm guessing that its because the malarial parasite needs human RBCs for completing its life ...
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67 views

Why does HPV Infect Squamous Epithelial Cells and Not Others?

I've seen this question about HPV and the reference therein. The link states "Human papillomavirus (HPV) is a DNA virus that presents tropism for epithelial cells, causing infections of the skin and ...
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1answer
83 views

What are most common natural causes of death? [closed]

What are most frequently occurring natural causes of death?
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144 views

Why is AIDS not a congenital disease?

AIDS can easily pass from mother to the newborn, then why do we not consider it to be a congenital disease (or syndrome)
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Comparing genetics [closed]

Compare the possible effect on an individual of knowing that they have genes predisposing them to type-2 diabetes and the dominant allele that causes Huntington's disease. I am not sure about the way ...
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44 views

On ways to treat cancer [closed]

If an area that has tumours is affected by some non-lethal disease would it kill the cancer cells first since the tumour cells are more 'unstable' ? Could this non-lethal disease 'process' be ...
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1answer
55 views

How was gene therapy able to cure diseases through the transformation of actively dividing cells?

I thought that gene therapy, when performed on target cells that regenerate themselves constantly, can be effective for a limited time only. I.e., the effect gradually wears off after a while, ...
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How “exactly” is Rabies transmitted?

Context: I know a person which has developed a sort of "phobia" with respect to touching things that has (even the slighest) chance of being in contact with something that can transmit rabies. For ...
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How much should one smoke in order to prevent Parkinson's? [closed]

There are studies who claim that nicotine has a neuroprotective effect against Parkinson's(such as this: http://www.ncbi.nlm.nih.gov/pubmed/11772120) What would be the minimum amount of nicotine(...
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Of people who develop Alzheimer disease, are those people genetically predisposed to it?

I have read a lot lately about microbiological pathogens that are found in blood vessels in the brain of patient's with Alzheimer disease (positive association). So, I am confused whether there are ...
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2answers
113 views

Do humans contract more physical sicknesses and diseases than animals do? [duplicate]

I wondered: If I get into the library and look into the medical section it is evident that there are thousands and thousands of different human physical diseases. But if I look into the section of ...
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Why does a Urinary Tract Infection cause a strong, persistent urge to urinate?

There are plenty of articles on the fact the a urinary tract infection (UTI) causes frequent and urgent urination. For example; on this National Institutes of Health webpage. My question is: Why ...
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1answer
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How can hyperthyroidism induce osteoporosis?

It says in my physiology notes that hyperthyroidism can cause osteoporosis. I've been trying to figure out how this could be possible for a little more than an hour now. Every article that I look at ...
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percentage of animal diseases caused by bacteria?

I know this is a long shot, but what is the approximate percentage out of all the animal diseases that are caused by bacteria? One of the Q&A websites answer it as 90, but is there any conclusive ...
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Why does type 3 systemic hypersensitivity not lead to shock?

Why does type 3 systemic hypersensitivity not lead to anaphylatic shock or hypovolumic shock, which shows the same features of type 1 systemic hypersensitivity like prolonged inflammation, production ...
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91 views

Can the spinal cord contain an “epileptic focus”?

I was wondering, is there a possibility of an something similar to an epileptic focus to exist within the spinal cord? Note I am using the terminology "epileptic" loosely here, principally for the ...
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Do other primates get gallstones?

Which non-human primates actually get gall stones the same as humans? All, some, none? References appreciated! Anecdotes about pet primates with gallstones also welcome if you have any...
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1answer
40 views

Spread of malaria from an infected person

If a person is infected with malaria, how can that person be a part of spreading malaria? As in, if a female anopheles mosquito sucks blood out of that infected individual, how is it possible that ...
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Steppe peoples method for healing horses' wounds

There was a custom among nomadic steppe peoples like Huns or Mongols of putting pieces of saltened meat in wounds of their horses to make them heal faster. Did it work? If so, how? I suppose it has ...
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128 views

How plasma cells switches secreting different Ig classes?

In Type 1 hypersensitivity how do B lymphocytes switch Ig classes, from synthesizing IgG to IgE? What is the mechanism? I studied multiple pathology books, it says the same as for IgG secreting ...
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297 views

Difference between protozoa, protists, protoctista?

Are these different classes of organisms or simply different names for the same?
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142 views

What causes the pain when a bone fracture is healing?

Why does a fracture still hurts when it is healing? I understand the pain at the beginning - the bone is not in its place, there is a pressure against the nerves, also the swelling pushes the nerves ...