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Offline DoctorBeaver

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What are the most common and deadliest diseases?
« on: 16/06/2007 06:30:10 »
Apart from colds & flu, what are the world's most common bacterial/viral diseases in humans? And which have the highest mortality rate?
« Last Edit: 16/06/2007 06:32:44 by DoctorBeaver »


 

Offline stana

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What are the most common and deadliest diseases?
« Reply #1 on: 16/06/2007 10:50:02 »
well cancer kills thousands in the UK..and the worst type is lung cancer :)

..and aids
 

Offline Negin -(Universe)

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What are the most common and deadliest diseases?
« Reply #2 on: 17/06/2007 18:06:53 »
I believe, TB and HIV are the deadliest pathogens
 

another_someone

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What are the most common and deadliest diseases?
« Reply #3 on: 17/06/2007 19:20:23 »
Cancer is a symptom, not a disease.

HPV is a very common virus that can induce cancer, as can the Epstein Barr virus.

Most very common pathogens are by their nature largely survivable.  HIV is at present borderline with regard to being highly common and with regard to being survivable.  Most people with TB with be symptomless carriers (if it were not so, the human race would already be extinct), but ofcourse there are a significant percentage of the population who do succumb to the potentially fatal disease.

HIV is not itself, in a direct sense, actually fatal; but will cause the body to become vulnerable to secondary infections, which can be fatal.  On the other hand, where appropriate treatment is provided (although such treatment is costly), there is no clear upper limit to the life expectancy that one can expect in living with HIV (although even then it continues to be a crippling disease, and there is no guarantee of success at keeping the disease at bay).

Malaria is another major killer, but ofcourse is not inevitably fatal to everybody.
 

Offline chris

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What are the most common and deadliest diseases?
« Reply #4 on: 18/06/2007 12:30:17 »
HIV is second only to tobacco as the leading cause of death worldwide.

Chris
 

Offline DoctorBeaver

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What are the most common and deadliest diseases?
« Reply #5 on: 18/06/2007 14:05:30 »
HIV is second only to tobacco as the leading cause of death worldwide.

Chris

That's a stunning fact.
 

Offline Bored chemist

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What are the most common and deadliest diseases?
« Reply #6 on: 18/06/2007 20:05:31 »
It seems to me to be 2 stunning facts.

As another someone pointed out, the commonest diseases are the least deadly. Things like warts that have practically no mortality are common. Things like ebola, which have exceptionally high mortallity rates, are very rare because they kill people before they get much chance to spread. This in turn is strong evidence that they are only accidentally diseases of humans and they have some other natural host where they do less harm.
 

Offline DoctorBeaver

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What are the most common and deadliest diseases?
« Reply #7 on: 18/06/2007 20:10:19 »
Maybe my phraseology was awry in the question. I meant to ask "which have the highest percentage mortality rate?".
 

another_someone

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What are the most common and deadliest diseases?
« Reply #8 on: 19/06/2007 09:17:40 »
HIV is second only to tobacco as the leading cause of death worldwide.

Chris

Both of these diseases show the difficulty in attribution of causes of death.

If someone who is suffering from HIV and is a smoker then dies of a lung infection, one can say that the lung infection was the direct cause of death, and one can point to both HIV and tobacco smoke as contributing factors; but can one say that either HIV or tobacco smoke were a provable causative agent (i.e. can one show without doubt that the man would not have died from the disease if neither of the other factors were present, or merely show that the likelihood of his dying would have been very significantly diminished)?

True, HIV does allow infection from diseases that are not common pathogens to humans, while tobacco smoke is not known to have this effect, so one might say that certain direct causes of death would be extremely unlikely to cause death to people who are not HIV sufferers; whereas with tobacco smoke, I know of no disease that is solely facilitated by tobacco smoke (it merely alters the probability of death through diseases that are common in the human population even in the absence of tobacco smoke).
 

Offline iko

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What are the most common and deadliest diseases?
« Reply #9 on: 19/06/2007 13:38:25 »
Kwashiorkor




Kwashiorkor

Classifications and external resources 
Kwashiorkor sufferers show signs of thinning hair, edema, inadequate growth, and weight loss. The stomatitis on the pictured infant indicate an accompanying Vitamin B deficiency.
Many of the children in this photograph from a Nigerian orphanage in the late 1960's show symptoms of malnutrition, with four in particular illustrating the gray-blond hair symptomatic of kwashiorkor.
Kwashiorkor is a type of childhood malnutrition with controversial causes, but commonly believed to be caused by insufficient protein intake. British pediatrician Cicely D. Williams introduced the name into international scientific circles in her 1935 Lancet article[1]. The name is derived from one of the Kwa languages of coastal Ghana and means "the one who is displaced" reflecting the development of the condition in the older child who has been weaned from the breast once a new sibling is born.
When a child is nursing, it receives certain amino acids vital to growth from its mother's milk. When the child is weaned, if the diet that replaces the milk is high in starches and carbohydrates, and deficient in protein (as is common in parts of the world where the bulk of the diet consists of starchy vegetables, or where famine has struck), the child may develop kwashiorkor.
Symptoms of kwashiorkor include a swollen abdomen, reddish discoloration of the hair and depigmented skin. The swollen abdomen is generally attributed to two causes: ascites due to altered oncotic pressure as a result of hypoalbuminemia (low albumin in the blood) and grossly enlarged liver due to fatty liver. This fatty change occurs because of the lack of apolipoproteins which transport lipids from the liver to tissues throughout the body. Additionally, the child has a miserable appearance with a "bull-dog" face. Generally, the disease can be treated by adding food energy and protein to the diet; however, mortality can be as high as 60% and it can have a long-term impact on a child's physical growth and, in severe cases, affect mental development.

From Wikipedia, the free encyclopedia:   http://en.wikipedia.org/wiki/Kwashiorkor






...
"Now we know that 50 percent of all deaths of young children in the world are due to malnutrition," Habicht says. "It's also because of illness, but if they were nourished, they would have survived. Looking at it that way makes a big difference in how you allocate resources."

click here for the complete articlehttp://www.nutrition.cornell.edu/news/s00/habicht0500.html

...



Life itself carries the highest risk of death.
Adults can decide whether to shorten their lives
eating too much food, drinking and smoking too much
and taking the risk of HIV infection from unprotected sex.
Major efforts should be concentrated, in my opinion, to reduce
children's overall mortality mostly due to malnutrition.
They too, will then be able to decide.

ikomment  [^]
« Last Edit: 20/06/2007 13:16:42 by iko »
 

Offline chris

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What are the most common and deadliest diseases?
« Reply #10 on: 23/06/2007 22:20:34 »
It seems to me to be 2 stunning facts.

As another someone pointed out, the commonest diseases are the least deadly. Things like warts that have practically no mortality are common. Things like ebola, which have exceptionally high mortallity rates, are very rare because they kill people before they get much chance to spread. This in turn is strong evidence that they are only accidentally diseases of humans and they have some other natural host where they do less harm.

This is absolutely right. Ebola is naturally an infection of fruit bats which periodically jumps into other mammals, chiefly primates and us, with devastating effect. It first appeared in 1976 and since then has killed about 1500 people.

Scientists have since mapped out the times of outbreaks and correlated them with weather patterns. The outbreaks tend to be associated with droughts. This suggests that scarce resources (mainly food and water) brings diverse groups of animals close together thus facilitating the spread of these agents.

Also, pressure of hunger drives species to eat food they otherwise wouldn't - like humans and primate species eating bats.

This is probably how these outbreaks are triggered. The virus is ill-adapted to primates and higer mammals and hence provokes severe infection. In it's natural bat host it's avirulent.

Chris
 

Offline DoctorBeaver

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What are the most common and deadliest diseases?
« Reply #11 on: 25/06/2007 21:09:22 »
Why is it that certain viruses are avirulent in some species yet devastating in others? What is it about the organisms that are susceptible to them?
 

Offline iko

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What are the most common and deadliest diseases?
« Reply #12 on: 25/06/2007 22:56:31 »
Why is it that certain viruses are avirulent in some species yet devastating in others? What is it about the organisms that are susceptible to them?

I was taught that viruses are selected to do the least harm to their specific 'hosts': if a healthy host carries viruses around for a long time, they indeed can proliferate, have their mutations and be selected for the best arrangement of genes, plus spread and visit new hosts and so on.
Behaving like this, their survival is guaranteed.
When something goes wrong and the infected organism dies, viruses succumb too, in hours. No way to preserve their fragile DNA/RNA in a decomposing corpse.This is the case of a mistaken species (monkeys-humans) or an overridden immune reaction of the host, probably due to a series of abnormal events or to genetic defects: fulminant brain damage (rabies) or hepatitis (HBV) and so-called hemorrhagic fevers (Lassa, Ebola) lead viruses to be buried together with their unfortunate patients.
Their vital host-cells die, so viruses disappear as well.
Their motto could be: "No trouble, will travel!".


ikod
« Last Edit: 27/06/2007 00:18:58 by iko »
 

jolly

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What are the most common and deadliest diseases?
« Reply #13 on: 25/06/2007 22:59:12 »
SARS was quite bad I thought, though not vey common.
« Last Edit: 26/06/2007 20:51:05 by jolly »
 

Offline chris

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What are the most common and deadliest diseases?
« Reply #14 on: 28/06/2007 08:28:30 »
The answer is evolution. If viruses killed off their natural hosts too efficiently then they would die out. Instead, over very long time scales, there is a balanced adaptation of the host to the pathogen and the pathogen to the host, in order to achieve a steady state. In some cases the virus can cease to function as a parasite at all and become something akin to a genetic symbiont.

A recent paper in Nature by Skip Virgin found that mice infected with the rodent equivalent of glandular fever (a herpes virus called MHV-68) were highly resistant to listeria or yersinia (plague) bacteria. Animals not carrying these viruses were much more vulnerable and all died.

Studies on the herpes-infected animals showed that the viral infection was tuning up the immune system by triggering increased production of an immune-boosting hormone called gamma-interferon.

The researchers concluded that because herpesviruses have been infecting their hosts for millions of years there has been an adaptation on the part of the host that requires infection with the virus to stimulate a key immune component.

So, extending this to other viruses, the agent becomes highly adapted to the host in order to maximise its persistence and infectivity in the population, and minimising its lethality. A good example of this is flu. The 1918 flu pandemic that killed 20-40 million people (2% of the world population (1 person in 50) at the time) actually had a case fatality rate of only about 1%. Contrast this with H5N1, which currently kills 70% of humans it infects. However, it doesn't spread efficiently amongst us yet. One would therefore anticipate that as it evolves to do so it will sacrifice some of that virulence.

The reason that these agents are more or less virulent in some species than others is because there are differences between the immune systems of different species, there are differences between the docking stations on the surfaces of cells of different species (making it more or less difficult for viruses to enter cells), and there are differences between the biochemical environments of individual cells in different species. Some or all of these factors contribute to the "species barrier", which affects the pathogenicity of an agent between different host organisms.

Chris

 

Offline iko

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What are the most common and deadliest diseases?
« Reply #15 on: 28/06/2007 09:57:33 »
Proper nutrition and sufficient sunlight exposure
with vitamin D production can make the difference
when our body's immune defense systems have to face
an infectious pathogen attack:


Talking of 'revisiting' and looking backwards,
allow me a cut&paste from Complementary Medicine
(Cod Liver Oil topic) and final comment from the
discussion in "Epidemic influenza and vitamin D"
J.J. Cannell et al. 2006.

Quote
Revisiting Vitamin D in humans.
just a few clever minds got this point
first, several years ago...



A hypothesis concerning deficiency of sunlight,
cold temperature, and influenza epidemics associated with
the onset of acute lymphoblastic leukemia in northern Finland.


Timonen TT.

University of Oulu, Department of Internal Medicine, Kajaanintie 50, FIN-90220 Oulu, Finland.

Research to detect new factors contributing to the etiology of acute leukemia (AL) is urgently needed. Located between latitudes 65 degrees and 70 degrees north, the population in northern Finland is exposed to extreme seasonal alterations of ultraviolet-B light and temperature. There is also a seasonal variation of both the 25(OH)- and 1,25(OH)2-D3 vitamin serum concentrations. In the present work, the frequencies of different types and age-groups at diagnosis of AL were compared during the dark and light months of the year, to uncover seasonality. Between January 1972 and December 1986, 300 consecutive patients aged >/=16 years and diagnosed as having AL were enrolled. The observed mean monthly global solar radiation, temperature measurements, and influenza epidemics were compared with the monthly occurrence of AL. Both acute lymphoblastic leukemia (ALL) (p=0.006) and total AL (p=0.015) were diagnosed excessively in the dark and cold compared with light and warm period of the year. There was a tendency for de novo leukemia to increase also in the dark and cold, but for acute myeloid leukemia (AML) patients the excess was not significant. Age >/=65 was strongly associated with the dark and cold season (p=0.003). Significantly more ALL (p=0.005) and de novo leukemias (p=0.029) were observed during influenza epidemics than during nonepidemic periods. However, a seasonality, i. e., the fluctuation of numbers of AL cases, was not determined, either monthly or during different photo- and temperature periods or influenza epidemics; this might be due to the small numbers of patients studied. Nevertheless, it is hypothesized that sunlight deprivation in the arctic winter can lead to a deficiency of the 1, 25(OH)2D3 vitamin, which might stimulate leukemic cell proliferation and block cell differentiation through dysregulation of growth factors in the bone marrow stromal cells, causing one mutation and an overt ALL in progenitor cells damaged during the current or the previous winter by influenza virus, the other mutation.

Ann Hematol. 1999 Sep;78(9):408-14
.




Epidemic influenza and vitamin D.

Cannell JJ, Vieth R, Umhau JC, Holick MF, Grant WB, Madronich S, Garland CF, Giovannucci E.
Atascadero State Hospital, 10333 El Camino Real, Atascadero, CA 93422, USA. jcannell@dmhash.state.ca.us

In 1981, R. Edgar Hope-Simpson proposed that a 'seasonal stimulus' intimately associated with solar radiation explained the remarkable seasonality of epidemic influenza. Solar radiation triggers robust seasonal vitamin D production in the skin; vitamin D deficiency is common in the winter, and activated vitamin D, 1,25(OH)2D, a steroid hormone, has profound effects on human immunity. 1,25(OH)2D acts as an immune system modulator, preventing excessive expression of inflammatory cytokines and increasing the 'oxidative burst' potential of macrophages. Perhaps most importantly, it dramatically stimulates the expression of potent anti-microbial peptides, which exist in neutrophils, monocytes, natural killer cells, and in epithelial cells lining the respiratory tract where they play a major role in protecting the lung from infection. Volunteers inoculated with live attenuated influenza virus are more likely to develop fever and serological evidence of an immune response in the winter. Vitamin D deficiency predisposes children to respiratory infections. Ultraviolet radiation (either from artificial sources or from sunlight) reduces the incidence of viral respiratory infections, as does cod liver oil (which contains vitamin D). An interventional study showed that vitamin D reduces the incidence of respiratory infections in children. We conclude that vitamin D, or lack of it, may be Hope-Simpson's 'seasonal stimulus'.

Epidemiol Infect. 2006 Dec;134(6):1129-40. Epub 2006 Sep 7.




...from the final conclusion in the full-text:

  Today, in a rush from multiplex reverse transcriptase-polymerase chain reactions that rapidly subtype influenza viruses to complex mathematical formulas that explain infectivity, many of us have forgotten Hope-Simpson's simple 'seasonal stimulus' theory for the lethal crop of influenza that sprouts around the winter solstice.   The faith and humility that characterized his life and his writings insulated him from despairing that his 'seasonal stimulus' would not be sought.  Among his last published words was the suggestion that 'it might be rewarding if persons, who are in a position to do so, will look more closely at the operative mechanisms that are causing such seasonal behaviour' [3,p.241].



A Gloucestershire GP carefully recorded the incidence of influenza in his practice over a period of nearly 30 years. Dr Hope-Simpson obtained a picture of the timing and intensity of these cases from 1946 to 1974.
Is it possible to compare Kilbourne’s chronological model of the spread of influenza with this data?
Such a comparison indicates that there should be evidence of the following factors influencing the final picture:
- A distinct seasonal pattern, with the highest incidence in winter.
- A series of decreases in the size of epidemic waves as the population becomes immune to one particular strain of the virus.
- The appearance of a new strain with changed antigens, meaning that the body’s defence mechanism does not recognise it. The whole process of infection should then begin again.
- The presence of more than one strain of influenza in the population at any one time.
- Newly introduced strains from other parts of the world, which can be especially virulent.

for more reading click here:  http://www.makingthemodernworld.org.uk/learning_modules/geography/05.TU.01/?section=6





 

Offline DoctorBeaver

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What are the most common and deadliest diseases?
« Reply #16 on: 28/06/2007 15:08:47 »
Chris & Iko - Thank you.
 

another_someone

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What are the most common and deadliest diseases?
« Reply #17 on: 28/06/2007 16:31:39 »
Why is it that certain viruses are avirulent in some species yet devastating in others? What is it about the organisms that are susceptible to them?

I have actually wondered whether this is not a double benefit (not only with regard to species, but with regard to races/breeds within species).

As Iko pointed out, a virus that kills its host is also killing its own chances of survival.

On the other hand, a virus that kills an alien (be it predator or competing species) will in effect benefit its own native host, and will thus ultimately also benefit itself.
 

Offline DoctorBeaver

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What are the most common and deadliest diseases?
« Reply #18 on: 28/06/2007 19:33:32 »
Why is it that certain viruses are avirulent in some species yet devastating in others? What is it about the organisms that are susceptible to them?

I have actually wondered whether this is not a double benefit (not only with regard to species, but with regard to races/breeds within species).

As Iko pointed out, a virus that kills its host is also killing its own chances of survival.

On the other hand, a virus that kills an alien (be it predator or competing species) will in effect benefit its own native host, and will thus ultimately also benefit itself.

Perverse symbiosis.  ???
 

Offline Carol-A

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What are the most common and deadliest diseases?
« Reply #19 on: 29/06/2007 18:17:39 »

There is a big difference between how many people a disease kills, and how many people who get it, die from a disease. Every year, between 1 and 3 million people die of Malaria, out of 350-500 million infections. Aids killed about 3 million people last year, but many more were infected and have not yet died. Rabies kills everyone who gets symptoms of it, but it only kills about 30,000 people a year.
 

Offline DoctorBeaver

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What are the most common and deadliest diseases?
« Reply #20 on: 29/06/2007 18:21:59 »
Does rabies really still kill that many?  :o
 

Offline iko

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What are the most common and deadliest diseases?
« Reply #21 on: 29/06/2007 18:50:09 »
Does rabies really still kill that many?  :o

Rabies is carried by bats mostly
and  bat bites can really be lethal.
Recently it has become a major concern
for the organ transplantation procedures too:



Transmission of rabies from an organ donor.

Lapierre V, Tiberghien P.

http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=15962404&ordinalpos=10&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
N Engl J Med. 2005 Mar 17;352(11):1103-11.


« Last Edit: 29/06/2007 18:52:42 by iko »
 

Offline ukmicky

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What are the most common and deadliest diseases?
« Reply #22 on: 29/06/2007 20:20:17 »
If you don't want to catch anything then the best thing to do is go on holiday.
I'm going to the Caribbean so my doctor has vaccinated me against diphtheria, tetanus, hepatitis A and hepatitis B.
 

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What are the most common and deadliest diseases?
« Reply #23 on: 30/06/2007 01:39:20 »
If you don't want to catch anything then the best thing to do is go on holiday.
I'm going to the Caribbean so my doctor has vaccinated me against diphtheria, tetanus, hepatitis A and hepatitis B.

I note you don't include rabies vaccinations - I believe they can be rather unpleasant.

Also, I am not sure that all bat rabies are the same strain - but vampire bats are particularly problematic.  Fruit bats, and other bats, can still carry the disease, but I think there it is a slightly different varient.
 

Offline ukmicky

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What are the most common and deadliest diseases?
« Reply #24 on: 30/06/2007 02:49:16 »
Their is also dengue fever where im going , sounds nasty that one
 

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What are the most common and deadliest diseases?
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