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Comment by est31 | Hacker News Reader

> Some 152 cases (and at least three deaths) were confirmed in Italy on Sunday, up from three cases on Thursday. The number of infected people in South Korea jumped to 763 (and six deaths) in just days.

To add an important point: In both countries, they have detected covid-19 only well after it has spread inside the country. E.g. in Italy it started with one severely ill patient who went to the hospital and got tested positive for covid-19. Then they recursively traced people that person has been in contact with and found over a hundred cases. They still haven't found "patient zero" yet, the first person in that chain who entered Italy with the disease. Before, it has been all in the dark. There are likely many such pools of carriers all over the world. This aspect of covid-19 is its real danger: in many cases the disease is asymptomatic so you don't get a test and keep interacting with people normally, but it's still able to infect others.

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Right, supposedly Denmark has no cases for example. I find that hard to believe, it seems more likely to me, given the average Danes dislike of going to the Doctor , and the average Doctor response of "you have some sort of virus come back in a couple weeks if it doesn't get better" that it is here, there are probably a few hundred walking around with it, and the first one to go to the hospital just hasn't happened yet.

If this is asymptomatic do they eventually get sick or do they just harbor the virus?

I don't understand how the virus can be asymptomatic? How does it reproduce and what triggers it to become symptomatic?

I think of asymptomatic infectivity as a sitting war between the virus and the host immune system. The virus has taken hold in a region where it a) does not grow at a rate harmful to the host and b) already has access to a spreading mechanism, while the immune system succeeds in keeping the infection away from organs where (either) c) the virus would grow at an unsustainable rate, eventually taking down it's host and/or d) the immune system's counter reaction would be so severe that it would endanger the host. Avoiding c) and d) are in the best interest of both virus and immune system (even though both are obviously not aware of any of that), so both are effectively happy. Sooner or later the immune system will develop a countermeasure nonetheless, but until then the virus will have spread to other hosts generously. Reliably reaching a state like that would be the second best evolutionary outcome of a virus, only topped by permanently resisting the immune system's removal attempts.

A virus doesn’t “want” to kill its host; just use the minimum change to propagate (e.g. induce a cough). In face some symptoms are your own body trying to dislodge it, such as fever, and the cough itself for that matter.

Some viruses of course have gone so far as to become part of our genome. Is that asymptomatic?

As other people said, most viral diseases have a asymptomatic period. What's unique about Coronavirus is that the patient can be infectious during the asymptomatic period. This makes coronavirus so hard to be controlled.

My understanding is that most viruses have some short period of infectiousness before symptoms develop, like the flu https://www.cdc.gov/flu/about/disease/spread.htm https://www.nhs.uk/common-health-questions/infections/how-lo...

Coronavirus however has a really long infectious period before symptoms can appear. Which I guess is to its evolutionary advantage and thus unlikely to disappear (just guessing on this part)

The virus can of course be asymptomatic, in fact it is asymptomatic in anyone when they first contract it. Then it’s up to their immune system to either fight it off or crumble. Whether symptoms show is just a matter of the severeness.

Symptoms like coughing and sneezing that discharge large droplets from the respiratory tract are a lot more effective at spreading the virus onto other hosts, but it appears that this virus is contagious enough that even asymptomatic hosts could spread it.

Being infected just means your cells have been infected and are starting to produce more viruses. That process is heavily dependent on viral load and the host's immune system. You're only symptomatic when your body begins a whole scale fight against the virus, before that, your body is still producing the virus (and you can spread it), but the virus isn't impacting you enough to be symptomatic.

There are several dark pools of concentrated yet totally unexplained and even implausible coronavirus being detected, with no clear discernible path from China. It leads me to wonder if the virus is a lot more long lived on surfaces or maybe in foods or on food packaging that came from China. How else to relatively cut off towns get an infection, but cities are not? Is there something that towns got from China that these cities may not have? Food stuff? agricultural supplies? Produce? … I am open to suggestions.

We have people who have never been and have no contact with anyone who has been to China, been in the vicinity of Chinese (e.g., tourist centers chocked full of Chinese tourists), or are Chinese; developing infections with Coronavirus. I am more than open to other suggestions and theories, but small towns in remote areas of Italy that have very little if any direct contact with the rest of the country, let alone China, especially over winter, seems quite peculiar; unless we simply have not identified (or officials are keeping secret) a far larger outbreak in cities.

And please don't try to tell me that western governments would not keep secrets or be dishonest. We are all adults and smart here, let's act like it.

Our media is referring to "patient zero" in Italy as a 38 years-old man. So either he is known or our media is full of your-know-that. Which would not be surprising.

Edit: a commenter below correctly pointed out that that 38yo man is being referred to as "patient one" not "patient zero". My bad.

That 38 year old man was the one I talked about above, the person who went to the hospital on whom they first found the disease, but not necessarily the person it originated from. Likely they have asked him (as well as anyone else affected) whether he's been outside of the country and he answered no (otherwise they'd say they have found the origin).

I'm not an expert, so I looked up what "Patient Zero" is defined as. Wikipedia [1] defines it as the case that has been detected first, but also says that media has used the term to refer to the source of the disease. So the Italian media's use actually matches the Wikipedia definition, while my use in the post above, as in this CNN post [2] matches the other definition. Sadly the term is a bit vauge.

[1]: https://en.wikipedia.org/wiki/Index_case

[2]: https://edition.cnn.com/2020/02/23/europe/italy-novel-corona...

Well, then our media is wrong.

I just read a CNN article entitled “Italy has yet to identify the source of its outbreak”, apparently from 8 minutes ago, citing a regional official.

https://edition.cnn.com/asia/live-news/coronavirus-outbreak-...

Things are developing very fast, expect that distortions from the chinese wispers games that is modern media to be worse than ever.

I've seen report that the first case was in contact with a person that had been in China but showed not symptoms and even might have tested negative at some point. If they get re-tested and show positive now, or some of their possessions do, that solves the mystery.

Dutch media reported yesterday that this person (who had been in China and had dinner with the 38 year old "patient 1") still tested negative on a second test, so the search for the real patient zero continued.

Didn't China changed how they were confirming cases to an MRI scan as people were still testing negative on tests 2-5 before testing positive.

Yes, but the problem with using that in this context is that an MRI scan can't fully distinguish COVID from other severe respiratory infections. It definitely won't work on someone who's asymptomatic.

I've been reading la Repubblica a lot today since I live pretty close to where the disease is spreading. They always reiterated that patient 0 who started spreading the virus in Italy is not yet identified. They had a "suspicious" person identified but that person later on was tested negative.

I think they're referring to him as "patient one". Patient zero (i.e. someone who is or was ill and has recently come back from China) hasn't been found yet.

Why does it have to be China? Couldn't it be Thailand/Singapore/S.Korea/Japan/Israel/Iran etc?

True, that would have been more correct. However, keep in mind that these people who are found ill now in Italy probably have contracted the virus weeks ago, before it started spreading substantially to other countries. Or before we knew it was already spreading anyway.

I'm strongly skeptical. Current research suggest mean incubation time is 5 days and stddev is 2 days. That means most cases will be asymptomatic within a week. Clearly, there were cases in the countries I listed above ~10 days ago, except Israel and maybe Iran was still in its infancy. The >20 days incubation time we see in news seems sensational and there is no research to back it up, except one non-peer-review paper published a few weeks ago.

Udik should have used e.g. rather than i.e.

You are correct. And to clarify further: I was talking about Lithuanian media, not the Italian one.

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