Thread: The origins of diseases spread by contagion

Back in my school days, a girl in my class asked the teacher how a dog gets rabies. The teacher replied by being bitten by another dog with rabies. The girl then asked how that other dog got rabies, and the teacher admitted to not knowing.

Rabies is spread by contagion. So is malaria. I cannot contract malaria from a mosquito bite unless the mosquito has previously bitten an infected person (or perhaps animal).

How did the first dog to have rabies get rabies? How did the first person (or animal) with malaria get malaria.

Are there any answers?

Viruses evolved, like other biological things.

Usually it is a disease jumping species after mutating.
Rabies is a good example. It seems to be fairly recent, only about 1500 years old.
Probably from insects to bats to foxes, but related viruses are plant pathogens.

I find the idea of plant pathogens jumping to animal hosts especially interesting. Remember that random mutations in the virus and hosts are what allow this species jumping.

Human scientists made many viruses so that their chemical companies can develop vaccine and sell them.

citation needed...

Originally Posted by cosmictraveler

Human scientists made many viruses so that their chemical companies can develop vaccine and sell them.

Utter and complete paranoid bullsh*t. Where did you decide that was a thing at all???

Originally Posted by ultimatesceptic

Back in my school days, a girl in my class asked the teacher how a dog gets rabies. The teacher replied by being bitten by another dog with rabies. The girl then asked how that other dog got rabies, and the teacher admitted to not knowing.

Rabies is spread by contagion. So is malaria. I cannot contract malaria from a mosquito bite unless the mosquito has previously bitten an infected person (or perhaps animal).

How did the first dog to have rabies get rabies? How did the first person (or animal) with malaria get malaria.

Are there any answers?

Do you understand how evolution works?

Originally Posted by cosmictraveler

Human scientists made many viruses so that their chemical companies can develop vaccine and sell them.

I sincerely hope this comment was a joke.

Originally Posted by mat5592

Originally Posted by cosmictraveler

Human scientists made many viruses so that their chemical companies can develop vaccine and sell them.

I sincerely hope this comment was a joke.

Simple deduction, and you have the truth.

Humans do create new strains of viruses, unknowingly, by being sick, and letting them mutate. Or by being a host/carrier.

Pharmaceutical companies do make a lot of money making vaccines.

Anyway, getting back to the actual question. The first dog got rabies, from another dog, or something that looked like a dog, that had a disease that looked genetically similar to rabies, but not rabies itself.

Go back 1.000.000.000 cycles, and you have the first thing that could be qualified as a disease, was created by creature, who had symbiosis with another creature before this. It "discovered" it could instead live off another organism without giving anything back. And so it probably began. (everything was based on random chance, and luck, and nothing was premeditated)

Humans do create new strains of viruses, unknowingly, by being sick, and letting them mutate. Or by being a host/carrier

Not what was meant or implied by cosmic, and you know it, unless your reading comprehension is worse than I gave you credit for...

Originally Posted by PhDemon

Humans do create new strains of viruses, unknowingly, by being sick, and letting them mutate. Or by being a host/carrier

Not what was meant or implied by cosmic, and you know it, unless your reading comprehension is worse than I gave you credit for...

It's pretty obvious that's not what he meant, as he literally said scientists made diseases so that they could sell vaccines for those diseases. Apparently we were really advanced thousands of years ago and created smallpox, rabies, etc.

Originally Posted by PhDemon

Humans do create new strains of viruses, unknowingly, by being sick, and letting them mutate. Or by being a host/carrier

Not what was meant or implied by cosmic, and you know it, unless your reading comprehension is worse than I gave you credit for...

I took Zwolver's comment to be a remarkably dry bit of sarcasm.

Geeez, calm down not all viruses were created by humans but some were.

I'd think that a good virus became a bad one due to mutation somewhere down the timeline.

citation still needed for the claim it was done solely to make money for companies selling vaccines for newly created diseases.

Originally Posted by cosmictraveler

Geeez, calm down not all viruses were created by humans but some were.

I'd think that a good virus became a bad one due to mutation somewhere down the timeline.

I still call bs on your assertion. Please supply the requested citations that back your claim

Originally Posted by Paleoichneum

Originally Posted by cosmictraveler

Geeez, calm down not all viruses were created by humans but some were.

I'd think that a good virus became a bad one due to mutation somewhere down the timeline.

I still call bs on your assertion. Please supply the requested citations that back your claim

And conspiracy theory based YouTubes won't do either. The citations have to be peer reviewed and accepted.

If I've got it right, the consensus point of view here is that contagious diseases arise by a process of random mutations in the original host/victim ... organism with the disease. I'm not sure what the correct terminology is.

If this is true, and I'm not saying that it isn't, then surely it would not (or at least should not) surprise us to see an entirely new contagious disease arise tomorrow.

Yes, but not just in the host. Evolutionary changes in the pathogen count too.

Sometimes bacteria that actually were beneficial in our body mutate into pathogens instead.

Originally Posted by ultimatesceptic

If I've got it right, the consensus point of view here is that contagious diseases arise by a process of random mutations in the original host/victim ... organism with the disease. I'm not sure what the correct terminology is.

If this is true, and I'm not saying that it isn't, then surely it would not (or at least should not) surprise us to see an entirely new contagious disease arise tomorrow.

"Entirely new" Yes new in the sense there was a mutation that enabled pathogenicity.
So the organism is a variant of an existing one so it is like a new model but not entirely new. It will deserve a new name and have a disease condition named after it. I think HIV fits into this category of recently evolved disease causing entities.
By "tomorrow" I think you mean "in the future" rather than Thursday 28th August 2014. It is not something that happens everyday AFAIK.

I personally think that Lyme disease is a failed attempt at making a biologic weapon. I think that its first public appearence in the 1950's, in Lyme, Conneticut just across from the WWII germ warfare labs on Plum Island, NY., is a very large coincidence, too large . Of course the US Army is admitting nothing. But they were working with white tail deer, and they reportedly were keeping them in pens with 10 foot high fences. White tails can jump over a fence that high. They can easily swim the width of Long Island sound.

The causative organism is not new but prior to its appearence in Lyme Ct it was not causing noticible human disease. ALtering an existing organism to make it more virulent is exactly what is done to "weaponize" a germ. The US government ran several germ warfare labs during WWII. Their safety techniques were not all that great. I have taken care of a doctor who picked up weaponized malta fever as a lab tech at an Army lab in Maryland. Thirty years later all it took was a slight physical stress, a broken arm, and he was in full blown relapse.

Originally Posted by Sealeaf

I personally think that Lyme disease is a failed attempt at making a biologic weapon. I think that its first public appearence in the 1950's, in Lyme, Conneticut just across from the WWII germ warfare labs on Plum Island, NY., is a very large coincidence, too large . Of course the US Army is admitting nothing. But they were working with white tail deer, and they reportedly were keeping them in pens with 10 foot high fences. White tails can jump over a fence that high. They can easily swim the width of Long Island sound.

The causative organism is not new but prior to its appearence in Lyme Ct it was not causing noticible human disease. ALtering an existing organism to make it more virulent is exactly what is done to "weaponize" a germ. The US government ran several germ warfare labs during WWII. Their safety techniques were not all that great. I have taken care of a doctor who picked up weaponized malta fever as a lab tech at an Army lab in Maryland. Thirty years later all it took was a slight physical stress, a broken arm, and he was in full blown relapse.

Urban myth.

Lyme Disease has been around for centuries https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2727481/

And the name was coined in 1975 not the 1950's

Originally Posted by Sealeaf

I personally think that Lyme disease is a failed attempt at making a biologic weapon. I think that its first public appearence in the 1950's, in Lyme, Conneticut just across from the WWII germ warfare labs on Plum Island, NY., is a very large coincidence, too large .

From Wiki:
"The examination of preserved museum specimens has found Borrelia DNA in an infected Ixodes ricinus tick from Germany that dates back to 1884, and from an infected mouse from Cape Cod that died in 1894.^[199] The 2010 autopsy of Ötzi the Iceman, a 5,300-year-old mummy, revealed the presence of the DNA sequence of Borrelia burgdorferi making him the earliest known human with Lyme disease."

Originally Posted by Sealeaf

The causative organism is not new but prior to its appearence in Lyme Ct it was not causing noticible human disease.

Considering the huge increases in population, it is still not causing much of a problem.


Add to that the fact it is non-fatal and is treatable with antibiotics, it is really not much of a weapon.

Originally Posted by ultimatesceptic

Back in my school days, a girl in my class asked the teacher how a dog gets rabies. The teacher replied by being bitten by another dog with rabies. The girl then asked how that other dog got rabies, and the teacher admitted to not knowing.

Rabies is spread by contagion. So is malaria. I cannot contract malaria from a mosquito bite unless the mosquito has previously bitten an infected person (or perhaps animal).

How did the first dog to have rabies get rabies? How did the first person (or animal) with malaria get malaria.

Are there any answers?

Actually, I think it's a pretty good question, and since viruses do not leave fossils, not easily answerable. Here's Wikipedia's explanation about the evolutionary origin of viruses:

"
Viruses are ancient. Studies at the molecular level have revealed relationships between viruses infecting organisms from each of the three domains of life and viral proteins that pre-date the divergence of life and thus the last universal common ancestor.^[1] This indicates that some viruses emerged early in the evolution of life,^[2] and that viruses have probably arisen multiple times.^[3]
There are three classical hypotheses on the origins of viruses: Viruses may have once been small cells that parasitised larger cells (the degeneracy hypothesis^[4][5] or reduction hypothesis^[6]); some viruses may have evolved from bits of DNA or RNA that "escaped" from the genes of a larger organism (the vagrancy hypothesis^[7] or escape hypothesis); or viruses could have evolved from complex molecules of protein and nucleic acid at the same time as cells first appeared on earth (the virus-first hypothesis).^[6]
None of these hypotheses was fully accepted: the regressive hypothesis did not explain why even the smallest of cellular parasites do not resemble viruses in any way. The escape hypothesis did not explain the complex capsids and other structures on virus particles. The virus-first hypothesis was quickly dismissed because it contravened the definition of viruses, in that they require host cells.^[6] Virologists are, however, beginning to reconsider and re-evaluate all three hypotheses.^[8][9]"

Add to that the fact it is non-fatal and is treatable with antibiotics, it is really not much of a weapon

Bio weapons in general are not very good weapons, principally because they are so hard to aim. An agent that makes people sick enough to seek and need medical treatment is nearly ideal for a bioweapon. You don't need to kill enemy troops you need them sick, not able to fight well and taking up medical resources. It is the same arguement that is used to justify full jacketed amunition for the military rather than the far more lethal expanding hollowpoint hunting amo. The Military would rather have a wounded enemy than a dead one.

The one case I absolutely do know about, that of the Doctor I treated, was infection with an agent that has been known for thousands of years, relapsing or Malta fever. It was not new. It had just been tweeked a bit. That the DNA of lyme disease has been around for thousands of years is not an arguement against Lyme disease being a weaponized version of it. It is instead exactly what one would expect. Something made an existing pathogen much more virulent, so that now significant preventive measures are taken about it and it is using medical resources to be treated. A tick bite used to be an annoyence that was treated at home. Now it is cause to go to the ER. The point of origen of this new, more virulent strain, is ten miles from the site of a known germ warfare lab. Easily within the 24 hour range of the principle animal vector, an animal vector that was kept at the germ warfare lab as experimental animals. Granted this is not iron clad proof but it is significant cause for suspicion.

Originally Posted by Sealeaf

Bio weapons in general are not very good weapons, principally because they are so hard to aim.

But Lyme disease is impossible to aim.
It also relies on ticks which require specific environmental conditions.
And it will infect soldiers on both sides equally.
And the ticks are only active for certain months of the year.
And it can be prevented with insect repellent.
And it takes months for any debilitating effect to occur...IF left untreated.

There is really no aspect of Lyme disease that would make it a bio-weapon.

Originally Posted by Sealeaf

That the DNA of lyme disease has been around for thousands of years is not an arguement against Lyme disease being a weaponized version of it. It is instead exactly what one would expect. Something made an existing pathogen much more virulent, so that now significant preventive measures are taken about it and it is using medical resources to be treated. A tick bite used to be an annoyence that was treated at home. Now it is cause to go to the ER. The point of origen of this new, more virulent strain, is ten miles from the site of a known germ warfare lab. Easily within the 24 hour range of the principle animal vector, an animal vector that was kept at the germ warfare lab as experimental animals. Granted this is not iron clad proof but it is significant cause for suspicion.

Could you provide some evidence that there is a 'new' strain and that it is more virulent?
(And a tick bite doesn't require you to go to ER to be treated for Lyme disease.)

Originally Posted by DianeG

Actually, I think it's a pretty good question, and since viruses do not leave fossils, not easily answerable. Here's Wikipedia's explanation about the evolutionary origin of viruses: .... ....

I didn't think bout going that far back. You are right it is a good question.
From nature.com:

No Single Hypothesis May Be Correct



Where viruses came from is not a simple question to answer. One can argue quite convincingly that certain viruses, such as the retroviruses, arose through a progressive process. Mobile genetic elements gained the ability to travel between cells, becoming infectious agents. One can also argue that large DNA viruses arose through a regressive process whereby once-independent entities lost key genes over time and adopted a parasitic replication strategy. Finally, the idea that viruses gave rise to life as we know it presents very intriguing possibilities. Perhaps today's viruses arose multiple times, via multiple mechanisms. Perhaps all viruses arose via a mechanism yet to be uncovered. Today's basic research in fields like microbiology, genomics, and structural biology may provide us with answers to this basic question.






Summary



Contemplating the origins of life fascinates both scientists and the general public. Understanding the evolutionary history of viruses may shed some light on this interesting topic. To date, no clear explanation for the origin(s) of viruses exists. Viruses may have arisen from mobile genetic elements that gained the ability to move between cells. They may be descendants of previously free-living organisms that adapted a parasitic replication strategy. Perhaps viruses existed before, and led to the evolution of, cellular life. Continuing studies may provide us with clearer answers. Or future studies may reveal that the answer is even murkier than it now appears.

Origin of Viruses | Learn Science at Scitable

This news story was an interesting bit too.
http://news.nationalgeographic.com/n...ution-origins/

Contagious,infectiousareusuallydistinguishedintechnicalmedicaluse.Contagious,literally“communicablebycontact,”describesaveryeasilytransmitteddiseaseasinfluenzaorthecommoncold.