Cancer as of now is not an infectious disease. The Papillomavirus, virtually, causes all cervical cancers and yet cervical cancer is "not considered" as an infectious disease? Some lung cancers of the smokers could, justifiably, be caused by papilloma virus and or other microorganismes, then why at least these cancers are not labeled as infectious diseases?
http://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents/hpv-fact-sheet
http://cancerres.aacrjournals.org/content/61/7/2799
http://www.ncbi.nlm.nih.gov/pubmed/15753007
https://www.google.com/search?q=papillomavirus+life+cycle&espv=2&biw=1536&bih=764&tbm=isch&imgil=qXHtnIwnwBgJ0M%253A%253BOwCyInRK2WQlDM%253Bhttp%25253A%25252F%25252Fwww.nature.com%25252Fnrc%25252Fjournal%25252Fv10%25252Fn8%25252Ffig_tab%25252Fnrc2886_F1.html&source=iu&pf=m&fir=qXHtnIwnwBgJ0M%253A%252COwCyInRK2WQlDM%252C_&usg=__eSwFOZ7k8xMuTLHprrOUAIsKQw4%3D&ved=0CDsQyjdqFQoTCJ7SzYOnkcgCFYoNkgod-ukIig&ei=t8cEVt6aLYqbyAT606PQCA#imgrc=qXHtnIwnwBgJ0M%3A&usg=__eSwFOZ7k8xMuTLHprrOUAIsKQw4%3D
http://www.the-scientist.com/?articles.view/articleNo/44003/title/Image-of-the-Day--Bridging-the-Gap/
http://www.nature.com/news/cancer-cells-can-infect-normal-neighbours-1.16212
https://www.quora.com/How-do-scientists-infect-mice-with-cancer
http://www.sfcdcp.org/flufacts.html
Dear Taissir,
In 2014’ survey of the factors associated with genital human papillomavirus infection among adult females in the United States, cervical cancers infectious to other people were not mentioned, or even suggested. The study found that 41.9% of U.S. females aged 18-59 years tested positive for genital HPV infection. It was determined that individuals with more sexual partners, with a lower education level, with non-Hispanic black race, and with no insurance were the populations at greatest risk.
Best wishes.
Ilya
Infectious diseases are ones that transmit by infecting others. Cancers do not infect people, though some of the risk factors for cancers may be infectious.
You could describe cervical cancer as a (relatively rare) complication of an HPV infection.
As already mentioned above, cervical cancer itself is not infectious.
and as is well documented many women may have a transient infection with HPV which does not cause dysplastic cell change and therefore does not cause cancer
Thank you, take for example the flu. If someone who has the flu and sneeze, the flu virus will make another person sick. The other components in the sneeze droplets are not going to cause the flu. The flu virus, e.g. in the sneeze droplets, upon contact with another susceptible healthy person will cause the flu in that person.
Then, it is true that not all cancers are infectious, but, for sure, some cancers are infectious. May be the misunderstanding is in the nomenclature. Furthermore, at least some essential aspects of cancers metastasization is really, I think, a cell-to-cell infection, basicly. Even though, the metastasizing cancer cell, which can not be considered as a normal cell anymore, is not a "virus" but by all means it could be considered an infectious agent.
Another example, may be is the prion diseases. The prion assume the rule of infecting other normal proteins.
The term "infectious agent" may be should be extended (or updated) beyond the classical nomenclature or terminology i.e. a foreign living organism, per se, such as bacteria, protozoa, fungi, helminths (worms), and viruses.
https://www.google.com/search?q=infectious+agent&oq=infectious+agent&aqs=chrome..69i57j69i65&sourceid=chrome&es_sm=0&ie=UTF-8
http://www.the-scientist.com/?articles.view/articleNo/44003/title/Image-of-the-Day--Bridging-the-Gap/
A cancer cell during Metastatization starts growing in another location in the same animal. What are the chances of it growing in another host? If it can infect another animal, grow there with chances of further spread to other animals, then it can be defined infectious.
In case of prions, they are transmissible to other animals and replicate(?) in new host with a possibility of spreading to other animals.
Some HPV types are responsibile for appearing cervical cancer. However, man with HPV infections may be transite HPV infection to sexuall intercourse to female and than we have chronic HPV infection of cervix and conequtive cervical cancer.
Dear Taissir
certain cancers are indeed infectious and transmissible, such as veneral canine cancers or tasmanian devil facial disease. But to my knowledge there is no equivalent in humans to any of these transmissible cancers. Infection by oncogenic HPVs is a necessary prerequisite for developing virtually all cervical cancers, the vast majority of anal cancers, a significant fraction of vaginal cancers, and a subset of penile, vulvar and oropharyngeal cancers. But in cervix (the best studied among all anatomical locations) roughly 98% of the infections by oncogenic HPVs are resolved and do not lead to a lesion, and roughly 98% of the lesions do not progress to cancers.
So, oncogenic HPVs are transmissible, but the cancers they cause are not.
HPV viruses and HSV viruses have possible oncogenic potention (11, 16 and other types), with very late period of appaeraing of cancer.
Infections or infectious diseases are defined as being transmissible. The cancers they may lead to are possible consequences, but per se not transmissible. Therefore, they should not be called infectious diseases.
Again, these tumors are possible manifestations of the respective infections or infectious diseases, but not involved in further transmission of the infectious agents. It's a matter of semantics!
Thank you, we do not say that the flu is a possible manifestation of the flu virus, we say that the flu is an infectious disease that is caused by the flu virus. Same should be said about papillomavirus and cervical cancer. The flu virus can cause, in this case, "only" the flu disease. Maybe this is why it was a straightforward matter. But in the case of papillomavirus there is more reasoning. Let's not forget only until recently that we have accepted the idea that papillomavirus could indeed cause cancer let alone now we have to accept or at least think about the idea that it is infectious! In addition, there are some studies that shows that at a certain point the cancerous cell itself, no other, become the infecting agent, e.g. no virus needed! Also, there are many research where mice are infected with cancer by infecting them with cancer cells "only".
Let us visit Koch's Postulates
Four criteria that were established by Robert Koch to identify the causative agent of a particular disease, these include:
the microorganism or other pathogen must be present in all cases of the disease
the pathogen can be isolated from the diseased host and grown in pure culture
the pathogen from the pure culture must cause the disease when inoculated into a healthy, susceptible laboratory animal
the pathogen must be reisolated from the new host and shown to be the same as the originally inoculated pathogen
HPV virus follows the postulates not the cancer cells.
For the argument about your argument" Also, there are many research where mice are infected with cancer by infecting them with cancer cells "only"" it can never fulfill the last criteria.
infection are the result of micro-organism invasion and can be cured with antibiotics or antibodies, while most of the cancers are due to oncogenic transformation of some cells of the own body.
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