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You can expect that someone drinking from a water source regularly will develop immunity to the pathogens in that water source by being repeatedly exposed to them. However, it's not quite right to say that poor quality drinking water impacts mostly tourists. It mostly impacts the people drinking that water, especially children. Immunity comes at a cost. Some ...


27

This is not completely clear to say the least, but there are some hints. Please keep in mind that there was not much time for extensive research, since this disease is still quite new. What seems clear (at least at the moment) is that most like the nerve cells (in the olfactory bulb as well as in the taste bud) are not directly affected, since they do not ...


6

According to Merriam-Webster Dictionary a Pandemic is: an outbreak of a disease that occurs over a wide geographic area and affects an exceptionally high proportion of the population : a pandemic outbreak of a disease Epidemics are considered a smaller scale version of a pandemic affecting a smaller region, community or population. Epidemics are obviously ...


5

@Remi.b is correct that you haven't given us very much information, but I think we can reconstruct what's going on. Suppose the population growth rate is written out as $$ \frac{dN}{dt} = N ( b - \delta - \gamma N) $$ then the equilibrium (carrying capacity) occurs when $N>0$ and $dN/dt=0$, i.e. $b - \delta - \gamma K = 0$. Solving this for $K$ gives $(...


4

Data are usually binned in broad age groups partly because that's all the detail that's useful in some context, and because access to more detailed data often involves access to strongly controlled, personally identifiable information. This preprint (full disclosure: I'm a co-author) gives information in 2-year bins for COVID in Ontario, e.g. this graph of ...


3

Would it help to think a little differently? Rubber bands (for example) aren’t alive either, but there are several ways they can be destroyed, including physically pulling them apart or just by having them exposed to air enough. Viruses are the same, conceptually. Soap works in part by dissolving the layer of fat that keeps the virus together. It also ends ...


3

My question concerns the way that $d$ enters the SIR model, because I find it not so plausible: to consider all persons that are infected today and take a fraction $ν$ of them that will have recovered tomorrow. Well, it is in fact not very 'realistic' as you point out, but in the assumptions of the model, we see that the population has no ...


2

The pathogens which are responsible for certain diseases have adapted to their hosts. Viruses need to attach to structures on their cells they invade to replicate. These structures usually consist of proteins and are unique for the respective species (e.g. the ACE2 receptor in the case of Covid-19). During an infection, there will be billions of viruses ...


2

A recent pre-print has studied this by measuring 86 accredited diagnostic parameters and plasma proteomes at 687 sampling points, in a cohort of 139 patients during hospitalisation. We identified 26 protein biomarkers and 14 routine diagnostic markers (Fig. 4a, Supp. Fig. SF20) that correlate with the time between the first sampling point and release from ...


1

No, on cannot say it this way, since further expose always carries a risk of getting infected. However, one could argue that after certain time of exposure one is nearly certainly infected, so being exposed longer doesn't really change the result. This statement could be formulated more rigorously in terms of compartamental epidemiological models. If we take ...


1

There are many prions other than PrP; it is often helpful to e.g. read wikipedia for these cases. For example, there are many yeast prions that are not homologous to PrP https://en.wikipedia.org/wiki/Fungal_prion. But even in humans there are a number of other proteins that form amyloids and are described as "prion-like" even though they aren't the ...


1

I am not sure if I quite understand your question, but I think your problem is here: removal (and your d) is a rate (time/removal). It does not matter what time you choose; a day, a week, a year, as long as you adjust your c (which is /time) to same timescale. In other words, if you wish to use d over several days, you need to calculate your contacts over ...


1

It may be too early to tell. Testing of dogs in Wuhan found no infected dogs "487 dogs including 90 beagle dogs, 147 pet dogs and 250 street dogs during the outbreak of SARS‐CoV‐2 were also tested serological negative." from https://onlinelibrary.wiley.com/doi/full/10.1111/tbed.13577 This article mentions deliberate infection of five dogs. on this very ...


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