Fictional Space Plague - Pandemic - Does this timeline make sense?

Question

For a book that I'm working on I am plotting out various points in time to make sure my plot is following accordingly. I apologize in advance for the lengthy post. It is a fungus-like infection that spreads in a few ways:

• Animals infected with the disease tend to not display deadly symptoms but instead act as carriers for the fungus, mutating in ways to help the spread of it. Birds with droppings of the fungus, on trees the fungus develops into conks
• Direct contact with the fungus can result in infection, especially through open wounds
• Humans infected with the disease develop fruiting bodies in their lungs, where the disease likes to grow. The fruiting bodies release spores in their breath and in coughing fits, which can infect humans in a relatively close proximity

Incubation Period - 0-1 days and the person is contagious, 3-4 days and the person is symptomatic, 5 - 7 days they are severely ill, 7-8 days they are dead.

R-Naught of about 20. Approximately 0.5-1 percent people are immune.

Symptoms - At first, standard cold symptoms, coughing, sneezing due to nasal passage irritation. Near end-stage, progressing to massive lung inflammation, blue veiny rash on the chest, coughing up blood, organic material like particulates, bloodshot eyes, paranoia in some if it gets into the brain stem. Upon death, the disease continues to grow throughout the body, consuming it for energy and in less than two days the fungus breaches the chest, mouth, etc releasing spores.

Timeline:

• Day 2 - Several people are exposed to the disease in Michigan, Illinois, and Indiana via direct contact with the disease along the coastline. The disease has also infected a group of approximately 20 people in Belarus. Estimated infected 100 - 200.
• Day 4 - Contagious individuals have spread the disease, some are starting to show symptoms of a nasty cold. Thousands are infected, but only a few are showing symptoms at this point that are warranting a healthcare visit. The disease has spread to the West Coast through airfare out of Chicago, as well as Atlanta, New York City. On the European side, several more are infected as families are exposed by the group, mainly in the baltic region.
• Day 6 - Approximately 50 deaths reported throughout the midwest from an unknown disease. CDC is investigating, WHO has been made aware. Concerned with the spread of a similar disease in the Baltic region with 20 deaths.
• Day 10 - Deaths are being reported with increasing intensity (100+), but the CDC / WHO are reluctant to give official numbers. Downplaying the severity to avoid panic. Social media is tweeting about it being more severe than that are letting on and that there are reports that people are getting sick in various locations throughout the country now, but tweets are being deleted. Surge centers for support are being set up in some major cities to assist with the influx of patients. Several locations are closing early due to lack of staff in restaurants and stores.
• Day 11 - Many people are attacking similar to preparing for a natural disaster like a hurricane, grocery stores are having problems keeping things in stock. Video leaks on twitter showing the fungus-like growths on a human body from the morgue of a hospital in Chicago. Twitter blows up, the original tweet gets taken down, but copies have already been made and are spreading. At night the CDC / WHO gives a press conference explaining the leaked video since their hand has been forced. Explaining that the cases are related to a disease never-before-seen, confirming the cases spreading throughout Europe and the States seem to be related. Quarantine measures are being put into effect immediately in several of the major cities (more of a public show of effort because they know it's too late to really try and control this)
• Day 14 - Thousands dead, work has been suspended in the city of Chicago, and in several cities. Riots are breaking out near hospitals and in major cities. Surge centers cannot keep up. Due to the fungus-like nature of the disease several pharmacies are being raided for anti-fungal treatments even though it doesn't really help. The fungus is spreading into several other species at this point, showing up in trees as a lichen style fungus.

That's the detailed timeline as is.

Is this timeline, given the background of the disease, realistic?

Answer 1

No, because your R-Naught and Incubation period are not consistent with each other.

I'll stress here that I am not an epidemiologist by profession and what I know about the topic comes from the research I've done in the past in related fields, but my sense of it is that your R-Naught figure is very high for such a short incubation period and symptomatic phase.

The first thing I need to do is articulate an assumption I am making in this question because it's not explicitly mentioned - I'm assuming a mortality rate of 100% given that you haven't listed one and death is mentioned as the 'final stage' of the symptomatic timeline.

Second, I have to point out that the R-Naught figure you have mentioned is higher than Measles (for example) which is believed to have an R-Naught between 12 and 18. Measles has an incubation period (from initial infection to the onset of rashes) of around 14 days on average and the infectee is infectious to others from around 2 days in. With your disease, your patients are long dead by then. That matters because the extra time means more people you can be around and infecting them without realising it. In this disease, that's much harder to do. Also, you don't need a large R-Naught to still cause big problems in any event. Just look at some of the other truly terrible diseases on the list and you can see that an R-Naught of 2 can do enough damage for people to take notice, especially with such a short incubation period.

Thirdly, it is important to note that with 100% mortality rate, even a highly infectious disease, while devastating, is going to burn itself out once people twig and put in adequate quarantine. The powers may sacrifice a city in the end, but it will be contained by virtue of the fact that the disease acts so quickly that people literally don't have time to get out of dodge and find themselves symptomatic and therefore subject to quarantine procedures too quickly to be able to act in a way that is going to cause massive spread.

That said - If the R-Naught is correct, the numbers you're describing are consistent with that but I just don't see it spreading to the level you describe with such a short incubation window. I do however see it taking out Chicago and a couple of other areas to which it spreads before the lockdowns go into effect but with such a short incubation window a lot would have to go wrong for this to go global.