"Infectious" versus "contagious" disease

Okay, my morning meeting went a bit faster than expected so I can sneak in a quick post before my first lecture. We were discussing infectious causes of cancer here. I received an email stating how "inconsistent" I was by asserting that a disease could be infectious but not contagious. So, rather than keep giving more examples of other chronic diseases that develop due to an infectious agent, I thought I'd take a different approach (after the jump...)

Y'see, as I've mentioned before, one of my interests is planning for any kind of major infectious disease outbreak--which includes bioterrorism. There's this little bacterium called Bacillus anthracis (AKA anthrax) that is a major concern on this front. In fact, it was already used in attacks in 2001 (still unsolved, I'll note). Anthrax is highly deadly, especially in the inhaled form. But there's one thing that's good about anthrax, from an outbreak standpoint: it's not contagious. It doesn't pass person-to-person, so only those exposed to the initial release of the bacterium have to worry.

Duesberg argues in a 1992 paper that microbes aren't the cause of cancer and other chronic diseases, including tertiary syphilis, kuru, and variant CJD. Though Duesberg gives a number of reasons for this assertion, he ends with, "above all, no human cancers and none of the 'slow viral diseases' are contagious." This was also the assertion made in the "infectious prostate cancer" thread. So, does this also rule out anthrax as having an infectious cause? Am I being "inconsistent" by calling anthrax an infectious disease, since it is not contagious?

Y'see why I don't find Duesberg et al. reliable authorities on infectious disease epidemiology?

More like this

This is an infectuous blog. But I don't think it's contagious. Or maybe it is.

I just saw a dead seagull on the east side of the 405 Freeway, 2 miles north of LAX. Everyone EVACUATE Los Angeles immediately! Thank you for your co-operation.

Tara,

A few comments:

1. It is Dr. Duesberg. He's a tenured professor at Berkeley, while you are an assistant professor at Iowa. Show a little respect.

2. Good for you for reading Dr. Duesberg's paper.

3. Comparing cancer to anthrax is beyond laughable. Anthrax is a ubiquitous little bacterium found on farms. This stupid fact sheet re Anthrax notes this important gem:

Before October 2001, the last case of inhalational anthrax in the U.S. in 1976. Before this outbreak of bioterroristic anthrax, only 18 cass of inhalational anthrax had been reported in the US in the 20th Century.

Are you kidding me? No cases in 30 years? A whopping total of 18 cases in 106 years in a country of now 300 million people!

Anthrax is much less dangerous than slipping in your bath tub, or getting hit by lightning.

More hype and exaggeration.

Now, as for "contagious" and "infectious", both are the same, the former simply means "highly infectious." Stop quibbling over semantics!

Bottom line:

Flu is an infectious disease, because it is caused by an infectious agent.

Ditto (tuberculosis, your favorite strep, measles, small pox, and a buncha others).

Cancer, however, is not caused by an infectious agent, and therefore is not an infectious or contagious disease. (At best, there is a few trivial exceptions to this, but even that is debateable.)

Cancer is a multi-factoral disease, the hallmark of which is defective DNA. Period. End of story.

The intriguing question is whether it is a defect at the gene level or the chromosome level.

I remain,

Hank Barnes

By Hank Barnes (not verified) on 06 Mar 2006 #permalink

Hank,

1. It is Dr. Duesberg. He's a tenured professor at Berkeley, while you are an assistant professor at Iowa. Show a little respect.

That's ridiculous and insulting. It is standard in scientific communication to refer to an author by their surname. In fact, as a senior in a neuroscience program who's spent the last year in a research laboratory, I have only rarely heard or encountered someone--whether it be a professor around the lab, someone teaching a class, or someone visiting to present a seminar--referred to as "doctor." And even then, it's generally been in a context that was either formal--such as an introduction--or very occasionally young undergrads talking to a professor.

Regardless, I find it odd that you would chastise someone who was also a PhD.--and therefore equivalently titled--in such a fashion while referring to her by her first name.

Cancer, however, is not caused by an infectious agent, and therefore is not an infectious or contagious disease. (At best, there is a few trivial exceptions to this, but even that is debateable.)

Cancer is a multi-factoral disease, the hallmark of which is defective DNA. Period. End of story.

As our hostess has pointed out previously, there is certainly far from that much certainty to the topic; to the point that I would argue that an oncologist or epidemiologist who made such a claim was on the verge of dishonesty.

Dr. Smith,

For what it's worth, from Steadman's:

Infectious

1. A disease capable of being transmitted from person to person, with or without actual contact.
2. Syn: infective
3. Denoting a disease due to the action of a microorganism.

Contagious

Relating to contagion; communicable or transmissible by contact with the sick or their fresh secretions or excretions.

Hank Barnes

By Hank Barnes (not verified) on 06 Mar 2006 #permalink

Oh, my! Isn't advanced, particularly metastatic cancer an infectious, but not contagious disease?

An alien new species of infective organism that arose within.

\In*fec"tious\:
----easily spread---"fear is exceedingly infectious; children catch it from their elders"-- Bertrand Russell.
----Having qualities that may infect.
----Corrupting, or tending to corrupt or contaminate.

Polly

[Despite everything, I believe that people are really good at heart--Anne Frank]

By Polly Anna (not verified) on 06 Mar 2006 #permalink

Of the many idiotic utterances of dr. Smith in the earlier discussion of 'virus-cancer' is the following:

"You attribute far too many magical powers to itty, bitty, 9kilobase viruses -- which can only
do one solitary thing -- replicate."

writes Hank, and the school marm slaps him with this:

"Wow, are you morphing into Harvey? Again, HepB is much smaller than that, but it's been shown to cause liver cancer." (dr. Smith)

Bigger, smaller, what the hell it's a biology blog, I can say anything.....

The quotation above is from:

http://bialystocker.net/cancercult.pdf

It contains even better ones that to too.

Hank writes: Cancer, however, is not caused by an infectious agent, and therefore is not an infectious or contagious disease. (At best, there is a few trivial exceptions to this

So you acknowledge that some cancers may involve viruses? That's progress, Hank!

"Cancer, however, is not caused by an infectious agent, and therefore is not an infectious or contagious disease. (At best, there is a few trivial exceptions to this, but even that is debateable.)"

How do you know, Hank? Once again, have you done the empirical research inorder to justify being so cocksure about the possible viral component of cancer?

If not, I think some modesty on your part would definitely be in order. I wouldn't want to think that you're infected with hubris.

GE

By Guitar Eddie (not verified) on 07 Mar 2006 #permalink

Apparently bialy comment-spamming is infectious (surely you caught it from somewhere, and it didn't just arise spontaneously here). I truly hope it isn't contagious as well...

And Hank, your stupidity is showing (no, wait, I'll be generous and just say your ignorance). Did you even read your own citation, much less the actual literature on anthrax? Hell, did you watch the news from 2001 when the anthrax attacks were occuring? Nevermind the biochemistry and microbiology showing the specific mechanisms of toxicity for anthrax, you have faith that it's all a bunch of bunk. By your logic, smallpox is less dangerous that being struck by lightning, just because we haven't had a major outbreak in a while. Oh wait, smallpox is probably just the result of malnutrition anyway, and the Variola virus is ubiquitous...

(sorry, Tara, couldn't help that last part. Looks like this thread is already bollixed anyway).

I just started looking at this blog, but I would like to comment on Hank's comments. "Cancer, however, is not caused by an infectious agent, and therefore is not an infectious or contagious disease. (At best, there is a few trivial exceptions to this, but even that is debateable.)" I'm going to guess that you have never heard of Helicobacter pylori. It has been implicated and been shown to cause gastric cancer. I hardly find that trivial.

Hank, you might also want to take a look at the latest issue of Cell which contains a review article by National Academy of Sciences member, Michael Karin on the link between infectious agents, inflammation and cancer.

Hank,

You miss--or are unable to understand--my point. It doesn't matter if anthrax causes a million illnesses a year or none.

Now, as for "contagious" and "infectious", both are the same, the former simply means "highly infectious." Stop quibbling over semantics!

Nope. Again, let's look at potential bioterrorism agent--tularemia (caused by Francisella tularensis). It's highly infectious--it only takes a few bacteria to cause an infection--but it's also not contagious. Care to try again, Hank?

So Tularemia is a vectorborne disease. Am I correct, Tara?
And there is no evidence that it can be transmitted person to person.

GE

By Guitar Eddie (not verified) on 07 Mar 2006 #permalink

It can be vector-borne. I'll C&P from the website I linked:

Many routes of human exposure to the tularemia bacteria are known to exist. The common routes include inoculation of the skin or mucous membranes with blood or tissue while handling infected animals, the bite of an infected tick, contact with fluids from infected deer flies or ticks, or handling or eating insufficiently cooked rabbit meat. Less common means of spread are drinking contaminated water, inhaling dust from contaminated soil or handling contaminated pelts or paws of animals. Tularemia is not spread from person to person.

Quick, tangential issue:

Harvey, why are you so obnoxious? Do you think it helps your cause? This is a sincere question.

Dr. Tara,

Hell, did you watch the news from 2001 when the anthrax attacks were occuring?

Yes, I watched a lotta chicken littles runnin' around with their heads cut off! I watched a bunch of know-nothing politicians and scientists yap about this and that, when nobody was hurt.

Fact:

1. Our country:
300 million people
2. Time Frame:
1900- Present
3. Anthrax injuries:
18

18 injuries in 106 years! I wonder how many folks died of "spontaneous combustion" during the same interval:)

This means 1 of 2 things. Anthrax may be harmful, but it is exceedingly sparse, and virtually undetectable. Or, Anthrax is harmless and abundant. Which do you think is the more plausible interpretation?

It is a joke to use "anthrax" as a point of comparison for any disease, since it is clinically inconsequential.

I'd be more worried about being struck by a f%^@$ing inter-galactic comet, than the anthrax bacterium!

Nevermind the biochemistry and microbiology showing the specific mechanisms of toxicity for anthrax, you have faith that it's all a bunch of bunk.

See, above facts (and light-hearted commentary)

Fondly,

Hank Barnes

By Hank Barnes (not verified) on 07 Mar 2006 #permalink

Hank,

I assume that inconsequential blather means you can't answer my question. That's OK--I'm used to it.

when nobody was hurt.

My, your sensitivity shines through again. Tell that to the families of those who died from it.

This means 1 of 2 things. Anthrax may be harmful, but it is exceedingly sparse, and virtually undetectable. Or, Anthrax is harmless and abundant. Which do you think is the more plausible interpretation?

Or 3.) The conditions for non-intentional anthrax infection have largely been eradicated in the US thanks to more rigorous safety measures, but it remains an easily weaponized and highly dangerous biological agent

False dichotomy, check.

It is a joke to use "anthrax" as a point of comparison for any disease, since it is clinically inconsequential.

And yet, clinical relevance does not matter when seeking examples for "infectious" versus "contagious", now does it? The mechanism of disease propagation is what matters, isn't it?

Straw man argument, check.

I'd be more worried about being struck by a f%^@$ing inter-galactic comet, than the anthrax bacterium!

I feel the need to remind all researchers here that informed consent from Hank would not be sufficient for most IRBs to allow experimentation on the progress of untreated anthrax, even though the data could be quite valuable. The same is true for HIV.

See, above facts (and light-hearted commentary)

And see my previous comment--by your lights, smallpox is harmless.

Truly, a staggering intellect.

Tara says:

Hell, did you watch the news from 2001 when the anthrax attacks were occuring?

To which Hank replies:

Yes, I watched a lotta chicken littles runnin' around with their heads cut off! I watched a bunch of know-nothing politicians and scientists yap about this and that, when nobody was hurt.

Emphasis added.

Nobody was hurt?? I suppose that's true if you don't count the 22 who were made ill and the 5 who died. Read that again .... Five people died.

2. Time Frame:
1900- Present
3. Anthrax injuries:
18

18 injuries in 106 years!

Source please.

Does this include the above figures (22 and 5)?

Does it include inhalation, cutaneous and ingestion vectors?

It is a joke to use "anthrax" as a point of comparison for any disease, since it is clinically inconsequential.

I'd be more worried about being struck by a f%^@$ing inter-galactic comet, than the anthrax bacterium!

Deliberate obtuseness.

Inhaled anthrax is infectious, but not contageous, n'est pas?

Dave S,

Beyond clueless.

Why do you think these 5 people died from anthrax, other than your parroting from these hysterical reports?

Aren't you geniuses always saying the plural of anecdote is not data?

This is from Wikipedia (admittedly, not a scientific source, but a pretty good factual source:

Robert Stevens, age 63, (Atlantis, Florida). The attack was in D.C., how did this 1 fellow get it from Florida?

Five Capitol police officers, three Russ Feingold staffers, 23 Tom Daschle staffers), test positive for the presence of anthrax (presumably via nasal swabs, etc.).
Were they injured in any way? Why didn't they bite the big one?

Thomas L. Morris, age 55, Brentwood, Maryland dies Youngish postal worker

Joseph P. Curseen, age 47,Brentwood, Maryland dies Youngish postal worker

Kathy Nguyen, age 61, a New York City hospital worker, dies. New York City?

Ottilie Lundgren, age 94 of Oxford, Connecticut, is diagnosed with inhalation anthrax and dies. I can only hope and pray I get 94 years on this earth!

I'm sorry, this just looks random and sporadic. Sure, the panic and hysteria can seemingly make connections, where none exist. But, I would expect people in Washington D.C. (where the anthrax was mostly detected) to be injured, not in Maryland, Florida, New York, nor 94 year old women in Connecticut.

The 2 Maryland postal workers would raise some eyebrows, though. It would be important to know a little about their medical history, though, wouldn't it? Do we know if they were previously healthy, or do we not care and just wanna go with the flow?

Bottom line. You have offered panickied, sporadic anecdotes, ginned up by the media.

I have offered 18 injuries in 106 years.

You be the judge on whether Anthrax, in general, is an infectious disease worthy of any discussion, whatsoever. If some Psychopath wants to culture a buncha anthrax and try to make innocent people sick, well he should be shot for being stupid. I'm glad he's working on that fringe, rather than a nuclear bomb.

Hank Barnes

By Hank Barnes (not verified) on 07 Mar 2006 #permalink

Oh my freakin' lord.

The attack was in D.C., how did this 1 fellow get it from Florida?

Do you really not remember this? A letter was sent to his employer as well--in Florida

As far as why others didn't die--many had cutaneous anthrax. Not as deadly as inhaled.

Why do you think these 5 people died from anthrax, other than your parroting from these hysterical reports?

Finally--what, you think this is all a conspiracy theory? The anthrax was isolated and sequenced, fer crimeny's sake--was that also just an endogenous genome? http://www.nature.com/nature/journal/v413/n6857/full/413657a0.html

Finally, I have a friend who worked in DC and New Jersey (where there were also contaminated mail facilities, genius) to clean up anthrax spores--it took *years* and millions of dollars. If it was all "hysteria," were all the folks involved in clean-up also crazy? Or part of the conspiracy?

Dr. Tara,

You have subtly deflected the conversation from anthrax in general to one bizarre episode from 2001.

I have no opinion on whether or not some psychopath can culture liters of anthrax and whether or not such extremely, high concentrations, if inhaled or digested will make a person sick.

I suspect it would -- the dose is the poison.

But that might be true for Lactobacillus bulgaricus (yogurt) as well.

Why not address my simple observations that 18 anthrax injuries in 106 years, means ...."don't worry about anthrax."

Why not address my simple observation that the big 4 cancers (lung, breast, colorectal, prostate) have not a goddamned thing to do with viruses?

Hank Barnes

By Hank Barnes (not verified) on 07 Mar 2006 #permalink

You have subtly deflected the conversation from anthrax in general to one bizarre episode from 2001.

Oh, the irony. I was discussing the "bizarre" 2001 episode because you hijacked the thread to discussing how "harmless" anthrax is, again ignoring the main issue of "infectious" vs. "contagious"

Why not address my simple observation that the big 4 cancers (lung, breast, colorectal, prostate) have not a goddamned thing to do with viruses?

What about skin cancer?

And Hank--if you recall, the virus I mentioned in the previous post *was* for prostate cancer. Additionally, other studies have found a virus associated with breast cancer, though those remain to be confirmed.

I've said before--it's estimated that viruses are a cause of about 20% of cancers. In some forms (such as cervical and liver), they're the main cause. In others, they may be a minor cause. You're ruling them out altogether, because "cancer is not infectious." Going to back off from that claim?

Hank -

I would not recommend you continue to try and substitute knowledge with bluster. As you can see (I hope by now) it's not going to work. Maybe next time you'd do your research first and then make your assertions. Works out better for everyone.

I would only add that my source was the CDC website, presumably a bit more reliable than Wiki, which in general is not bad.

The rest that Tara didn't cover warrants no further comment.*

I have offered 18 injuries in 106 years.

Indeed you have offered it. What you haven't offered is your source for this information. So I ask again.

*I would note one thing. Take a look at this map of Maryland. See the red dot? That's Brentwood. See the square directly adjacent to the southwest? That's Washington D.C.

I've said before--it's estimated that viruses are a cause of about 20% of cancers

Sorry, way to high. At best, 0-1%, although even this is highly dubious. The first "human cancer virus" was reported in 1980, by the sainted Robert Gallo.

I've noticed you people rely on outliers.

The big 4 cancer killers have nothing to do with viruses, but you argue the outliers.

Anthrax is a ubiquitous farm bacterium, that has registered a whopping 18 deaths in 106 years, but you take as gospel that 5 people including a 94 year old woman from Connecticut are alleged to have been killed by anthrax in the hysteria of a bizarre 2001 attack.

If I claimed that 5 random people from 4 different states all developed autism after taking a vaccine, you'd all flip out and go apesh%t (and be right, too!)

Truly stunning, how bad the young scientists are today. Mind boggling, the conformist, sheep mentality some of y'all have developed -- focusing on the trivial, missing the important. Never falsifying a belief, rarely debating, instilled with a pre-conceived set of opinions, reduced to:

Good: vaccines, evolution, anti-retrovirals, pharmaceutical drugs

Bad: alternative medicines, creationists, Bush, cancer-viruses, exotic bugs, avian flu bugs in Nigerian ostrichs.

And, then, when the biggest scientific frontier -- stem cell cloning -- turns out to be a massive fraud, the silence is deafening. Not a peep. One bad apple. Let's just move on. That's South Korea, it ain't us.....

The mind reels.

Hank

By Hank Barnes (not verified) on 07 Mar 2006 #permalink

Hank,

Do you even know what an "outlier" is? How 'bout a cite for that "0-1%" figure?

And again, you're incredibly wrong. Ever heard of Epstein-Barr virus? It was found to be a carcinogenic virus in humans in the 1960s.

If I claimed that 5 random people from 4 different states all developed autism after taking a vaccine, you'd all flip out and go apesh%t (and be right, too!)

Hank, have you studied all of those cases, apart from the "media hysteria?" How 'bout those sequenced genomes isolated from them?

And Hank, back to the main question--is anthrax "infectious?"

Hank writes : I've noticed you people rely on outliers.

No, Hank I think "those people" rely on the peer reviewed literature and the data. Perhaps in your mind, those information sources stand up poorly to unsubstantiated assertions and intuition, but some of us beg to differ.

Hank also writes: And, then, when the biggest scientific frontier -- stem cell cloning -- turns out to be a massive fraud, the silence is deafening.

Hank, what does that have to do with aetiology which, in case you've failed to notice, appears to be the subject of this blog.

Hank -

I see you continue to bluster and continue to fail to support your assertions by citing sources. Instead, you simply make more baseless assertions, possibly in the hope people will forget them in the general hub-bub.

A couple points.

I see you switched from "18 injuries in 106 years" to "18 deaths in 106 years". Interesting, but still no souce cited so we can verify these numbers. Of course this is only for the U.S., but apparently if it doesn't happen in the U.S., it doesn't count.

How can 0-1% be highly dubious? It already includes 0, doesn't it. Unless you want to argue that viruses can cure cancer?

That one bit of research into stem cell cloning turned out to be bad (your link is bad) hardly indicates the entire field is nothing but one massive fraud. If that were true, then by that standard I'd say that every field in science is a fraud.

I'm going to pop in again. Hank, I will grant that cancers start because of a genetic mutation. It usually occurs when a growth factor gene is turned on and a growth suppressor turned off. I apologize if some of this isn't quite accurate. I'm an undergraduate student, and there's been some time since my microbial genetics course. Viruses can cause these mutations when they incorporate their DNA into the host DNA as they enter the lysogenic life cycle. When they revert to the lytic cycle and remove their DNA, they can remove host genes that may play a role. Viruses can also act as transposable elements and interrupt genes that should be turned on. On the infectious vs. contagious argument, I will state that an infectious agent is an organism, usually microscopic, that causes an infection in another organism. A contagious agent is an infectious agent that can be easily passed from one organism to another. Thus, all contagious agents are infectious agents, but not all infectious agents are contagious agents.

Tara,

I'm begining to see what you mean. Hank is good for a few laughs. He's kind of like William F. Buckley Jr. except the he bloviates with a great deal more stridency.

Eddie

By Guitar Eddie (not verified) on 08 Mar 2006 #permalink

Polly - I am a real layperson WRT oncology - I took an interesting biochemistry seminar 20 years ago dealing with cancer - so that should convince you of my level of ignorance.

I'm wondering this though, given that metastatic cells are basically evil little colonizers, is it possible to 'infect', say, a healthy mouse by injecting a few metastatic cells from a cancerous mouse? Do macrophages just come take 'em apart?

I had the impression that most of the 'infectuous' causes of cancers worked as a secondary factor of some kind. Chronic infections which conincided with malignant tumors. It seems to me that viral agents have some non-zero probability of causing a cancerous mutation in the host cell DNA (I mean, this IS what they do - insert DNA), something that will 'eventually' happen in a chronic case. I guess the mechanism of the non-mutated virual or host DNA disease doesn't normally 'cause' cancer itself, but neither does the benzene in a single smoked cigarette. It takes prolonged exposure to hit an observable probability of DNA damage. We certainly still condsider cigarettes to be cancerous; why not HPV?

By Montpellier (not verified) on 08 Mar 2006 #permalink

Zach - my apologies - you were all over it ahead of me. :-)

So, when I first started lurking here, I thought, it's a geek blog, it'll have very high S/N content, with intelligent debate - where all participants play by the same collegial rules - but, heh..I see we get cirucses here too! And, I work in academia...I should've known better ;-).

Dr. Smith - congratulations - I think now that you're bedevilled by your very own crackpots, you can fairly say you've arrived!

By Montpellier (not verified) on 08 Mar 2006 #permalink

Hank said (with my emphasis)

Dr. Smith,

For what it's worth, from Steadman's:

Infectious

1. A disease capable of being transmitted from person to person, with or without actual contact.
2. Syn: infective
3. Denoting a disease due to the action of a microorganism.

Contagious

Relating to contagion; communicable or transmissible by contact with the sick or their fresh secretions or excretions.

Truly stunning, how bad the young scientists are today.

You mean their ability to read a dictionary?