This is widespread with street dogs (and "street" dogs) where I live in Mexico. It can get pretty nasty.
Female dogs will typically get tumor growths on the vagina, and at its worst will look like someone took a meat grinder to her parts. It will blow up in size and at some point the dog will succumb and die.
The male dog will get it in the penis, and typically will be caught sooner as bloody discharge from a male dog is something that raises a red flag quicker.
My mother-in-law has had 3 dogs get infected at different points in time, one female that had to be put down and two male that recovered.
One of our dogs acquired a CTVT tumour in the nasal tract, which is rarer. It resulted in a bloody discharge via one nostril which thankfully led to an early diagnosis (although it remains curable up to quite a late stage as the vet told us).
Our boy has had his chemo and seems fully recovered: swelling is gone, bleeding and reverse-sneezing have stopped, appetite is back to normal, all signs of lethargy and malaise are gone. Hopefully he will remain tumour-free.
That's sad, because it's trivially curable, supposedly. Man, if they'd snip those male dogs' with a vasectomy, what an improvement it would be...same here north of the mexico-us border.
Sure, but who pays for spaying and neutering the plethora of street dogs in the poorest states in Mexico? And many people have dogs without the means of paying for this (or any) kind of surgery.
Between us and my MIL we have 10 dogs, and all of them except one are fixed. I've made sure of that. I'm not able to win the argument over the last one, but it's old now anyways. The dogs she had that got sick was from before I was in the picture.
"Our analyses reveal a mutational signature, signature A, that occurred in the past but ceased to be active from about 1000 years ago. A recent study (37) detected evidence for an excess of C>T mutations at TCC contexts, the mutation type most prevalent in signature A, accumulating in the human germ line between 15,000 and 2000 years ago. If this human mutation pulse is due to signature A, it could indicate a shared environmental exposure that was once widespread but has now disappeared."
There will now be a small academic race to identify this mysterious carcinogen which both humans and this dog cancer were previously exposed to.
Clonally transmissible cancers are typically only seen in highly inbred populations. Tasmanian devils qualify because they went through a population bottleneck when they first colonized the island. Dogs qualify because of human breeding. (It's pretty unlikely that CTVT could be transferred to a wolf, even though pet dogs and wolves are the same species.)
The reason most cancers aren't transferrable, is the same reason that organ transplants are so hard. Most individuals in most species have unique antigen profiles. The immune system attacks any foreign bodies without matching antigens. An internally generated tumor works because it's cloned from an individual's own cells.
But a foreign tumor, is very unlikely to have a matching antigen profile. Therefore the immune system will attack and destroy with extreme prejudice. However a highly inbred population may lack the sufficient genetic diversity to have individually unique antigen profiles. In the extreme case if we were all clones we could pass tumors back and forth with ease.
The short answer is that it would be virtually impossible to see any widespread cases of clonally transmissible cancers in non-immunocompromised humans.
I suppose it depends on their individual immune systems. If they didn't live in close contact, they may not share the same immune system. One may have a weaker immune system than the other making it possible for the cancer to spread easily one way but not the other.
Interesting question. I suppose so. I know identical twins can typically receive organ transplants from each other with complications. So theoretically they should be able to receive tumor transplants (which is what clonal transmissible cancer is).
I wouldn't be so sure, a cancer that doesn't express classical MHC but still manages to suppress NK cells has a chance. It would probably have to master a few other immunosuppressive pathways but it's not beyond imagination.
Transplanted HeLa cells were shown to engraft in unrelated human "subjects" (in some truly evil experiments by https://en.wikipedia.org/wiki/Chester_M._Southam), other cell lines probably have the same capacity.
So if you have a population of humans who, for generations, have selected genes via inbreeding, would it be a thing to have transmissible cancer?
I'm thinking of the Amish population near my hometown that has definite inbreeding traits and particular disabilities associated with inbreeding in their bloodline/families.
Would it be possible for them to develop some kind of transmissible cancer?
Human cancers aren't contagious, at least not the way the cancer in the article is. Some risk factors for cancer, like HPV, are contagious in humans, but those aren't cancers themselves.
The "lie" (which was not a lie at all) that you were told actually meant that you can't get cancer from being around someone with cancer. That's still true.
It's largely true, and teaching it that way to school kids is important so they don't avoid friends/family who may have cancer of some sort. My son's friend has cancer and it was one of his first questions - "can I catch it?"
The rare human cancers that are transmissible like cervical cancer get covered in sex-ed, and interventions like condoms are effective.
“It’s very mysterious,” Murchison says. “This cancer was exposed to something that caused this very particular mutation, and has never been seen in any human cancer ever, and that seems to have stopped 2,000 years ago. We don’t know what that carcinogen is, and we’d love to. I guess it was probably something in the dogs’ environment? This is a very crazy idea and we don’t really believe it, but maybe ancient people who owned the dogs tried to treat [their tumors] with some kind of chemical?”
This feels wrong - surely particular carcinogens don't cause particular mutations. Isn't this just chance?
The article states that different carcinogens do cause particular styles of mutation.
> Many carcinogens mutate DNA in distinctive ways: Sunlight, for example, creates a very different pattern of mutations than cigarette smoke. Murchison’s team found that CTVT contains a lot of those sunlight signatures, especially at lower latitudes, where the sun is stronger. For example, CTVT in Mauritius has more sunlight-induced mutations than the same tumor in Russia.
Particular carcinogens absolutely do cause particular mutations or at least mutational patterns. Lookup mutational signatures. Signature 4 for smoking for example
The most obvious way is that carcinogens affect parts of the body differently. Iodine collects in the thyroid, some compounds accumulate in the gut, alpha and beta affects the outer layers of the body.
Epigenetics can cause different parts of DNA to be more or less exposed in different parts of the body. There are also indirect effects from chemicals- some carcinogens can cause changes in proteins, or be bound to proteins, which can cause them to be around certain regions of DNA more.
Mostly though you see that kind of thing more in viral/bacterial cancers- a sizeable percentage of all tumors are caused this way.
The article suggests that mutation patterns arise in predictable ways depending on the carcinogen, which is how they pinpointed the origin of CTVT to China.
> Its future is uncertain, though. While failing to acquire beneficial mutations, CTVT is also failing to weed out harmful ones. That’s understandable, because much of its DNA comprises genes for building a dog
No, nothing like this has ever been observed in humans.
Per Wiki:
> There are no reported human cases of clonally transmissible cancers that can independently survive and be transferred in the manner of CTVT and DFTD. However, instances of one human passing cancer cells to another through physical contact have been reported. These cases typically involve organ or hematopoietic stem cell transplants or cancers transferred from a pregnant mother to her fetus.[66] The difference of these incidences from a true clonally transmissible cancer, however, is that the cases of human transfer were one-off events — the actual tumor did not have properties allowing it to be continually transferred throughout the population, and therefore the tumor clone went extinct with the death of the host individuals.
Don't you get HPV vax way late in life. Like waay after autism diagnosis.
I don't know much about anti vaxers. I just remember something about how it causes autism (they think). And often diagnosis is around the time early childhood vaxination is done.
Sonmy question is what does a late child vax for HPV do (in their words).
Anti-vaxx reasoning can be repackaged for any circumstance. In this case, they look for rare, tragic outcomes in teenagers the proper age for the HPV vaccine, look for temporal correlation, and blame it on the vaccine.
There are a lot of questions around Gardasil vaccine.
I have a friend that had the vaccine and she has her body paralized 3 years for 3 years now. She's 17 years old, living in a bed and suffering depression. I know there could be another cause for her paralisys but the vaccine is still the most probable cause, so having the vaccine was her worst decision of her life.
There are a handful of cases of Guillain–Barré annually that coincide with the HPV vaccine administration. Flu vaccine is known to cause the same thing in rare cases, as well. But...
> “Our results show that Guillain-Barré is not occurring more often after HPV vaccination than it does in the general population.”
Side note: Even if the vaccination caused all 36 cases described in a two-year period, and even if that were elevated from the normal incidence in the unvaccinated population, HPV causes thousands of deaths annually from cervical cancer. Public health should be a matter of statistics, not anecdotes.
Well, is obvious I'm talking about a personal anecdote. Did I cite any investigation?
For the family of that girl and her close circle that is the image they have of the vaccine. I'm not saying the vaccine cause paralisis. I'm saying that for her it was the cause, they still don't have another explanation (no gillan-barre, nor wierd infection). Thats why in Colombia just a few people will allow to get that vaccine, out there you will find few cases like the one of my friend, but enough to make most woman reject its aplication.
Its just a view from that population perspective and why it impacts on the acceptance of the drug.
> To clarify, several cancers can be caused by infectious entities; cervical cancer, for example, is the work of HPV, a sexually transmitted virus. But in those cases, the cancer itself is not infectious and cannot spread. CTVT is different: Each cancer cell is a free-living parasite that can set up another tumor on another dog.
Put another way, HPV is a virus whose effects can cause cancer. That is, it causes mutations in _your own_ cells that cause them to become cancerous.
CTVT is essentially a parasitic cell line — not your cells hopping a ride on you.
No, this closer to the HeLa cell line. Initially it took significant effort to grow these cancer cells, but after evolution in a research environment now they easily contaminate other experiments. https://en.m.wikipedia.org/wiki/HeLa
Similarly, a cancer that started in a specific dog ended up evolving to survive in different animals.
>To clarify, several cancers can be caused by infectious entities; cervical cancer, for example, is the work of HPV, a sexually transmitted virus. But in those cases, the cancer itself is not infectious and cannot spread. CTVT is different: Each cancer cell is a free-living parasite that can set up another tumor on another dog.
HPV can also (rarely) cause cancers of the throat and penis.
Not as terrified as I was when one of our dogs got hemangiosarcoma, a canine-only cancer of the cells that line the inside of blood vessels. It took three weeks from the first symptoms to when he died. That's actually a long time - in many cases, the first symptom of the cancer is that the dog is dead.
SIV appeared somewhere between 1000 and 20000 years ago. Then ~100 years ago, it mutated to HIV and shortly after infected humans. We never know what could happen.
> Its future is uncertain, though. While failing to acquire beneficial mutations, CTVT is also failing to weed out harmful ones. That’s understandable, because much of its DNA comprises genes for building a dog. It can afford to let those mutate into obsolescence. But over time, the genes that it still needs will also take hits. Slowly, the tumor will become weaker and less efficient.
I wonder if there's an analogy to governments and laws. As our laws become more complex and "mutate," governments gradually become less effective.
Female dogs will typically get tumor growths on the vagina, and at its worst will look like someone took a meat grinder to her parts. It will blow up in size and at some point the dog will succumb and die.
The male dog will get it in the penis, and typically will be caught sooner as bloody discharge from a male dog is something that raises a red flag quicker.
My mother-in-law has had 3 dogs get infected at different points in time, one female that had to be put down and two male that recovered.