I was looking for more than just a Google answer, for relative abundance it would seem there are massive deposits where it is found but yes, absolutely, there is very little NaCl in the universe.

We don't really know, a lot of mammals are also highly resistant to prions so it's thought it's an issue of susceptibility.

Prions only affect mammals. Cows also don't partake in cannibalism, we grind up cattle into protein powder and mix it into cow feed as a supplement. All mammals can get sporadic cases so there are laws about feeding animals to their same species because while rare, there's a risk.

Kuru is absolutely caused by cannibalism. It started off because sporadic CJD happens in about 1/1m people and because of ritualistic eating of the brain and spinal cord it became transmissible variant CJD.

About 90% of CJD is sporadic.

Cannibalism is just a form of transmission, prions self propagate by causing misfolding of healthy PrPs which accumulate into amyloids and cause disease.

Omicron isn't a single serotype (immune recognition), it's actually a ton:

https://covid.cdc.gov/covid-data-tracker/#variant-proportions

So this isn't waning immunity, it's serotype emergence that escapes immunity.

ELI5: we get a great pitcher versus the first batter but they keep changing batters as we strike them out until eventually our pitcher is terrible. Then we bring in a new pitcher to match against the best batter we've seen so far and it starts all over again.

We really don't know much about serotype specific waning immunity, it's likely we'll have robust long term immunity from the earlier variants like alpha and delta.

The whole issue of "re-infections" is that new serotypes keep emerging not that people keep getting reinfected with the same variant.

If anyone is interested in infectious disease news: r/ID_News

It's a long, progressive disease, the usual first visible symptom is weight loss because by that point of brain damage the deer drastically reduces eating and drinking. More subtle symptoms would have likely been around for much longer.

And that rapid climate warming doesn't result in tropics, it results in deserts.

Right, I suppose you don't think there's an anthropocene mass extinction?

Read this:

https://www.pnas.org/doi/10.1073/pnas.2023989118

Water, pollution, pesticides, encroachment/habitat loss, extreme weather....

A few things against a stable and prosperous environment.

Do you have any references or is this just a lay opinion? From what I've seen, not my field, it would seem fairly dire.

Given the immune environment of bats, it's thought that most hemorrhagic fevers are evolved from them.

https://www.nature.com/articles/s41586-020-03128-0

There has certainly been a lot of press around Kitum cave but there are earlier recorded outbreaks and the pinpoint origin really can't be said definitively since viral studies were pretty cutting edge 50 years ago.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4166725/

https://academic.oup.com/trstmh/article/109/6/366/2461644

Of course, just saying it likely originated from bats doesn't really give the whole current story, there are many mammals that are thought to act as reservoir species so the cat is out of the bag...

https://www.science.org/doi/10.1126/science.1172705?url_ver=Z39.88-2003

https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004815

Took a little digging but Dorothy Tovar provided some great bat facts in this COVID AMA:

https://www.reddit.com/r/science/comments/ezstsw/science_discussion_series_the_novel_coronavirus/

Most studies just use ART usage as a proxy for viral load but it makes a huge (>90%) risk reduction.

https://www.thelancet.com/journals/lanhiv/article/PIIS2352-3018(22)00289-2/fulltext

https://onlinelibrary.wiley.com/doi/10.1111/hiv.12397

https://www.frontiersin.org/articles/10.3389/fpubh.2019.00401/full

A few things to clear up:

HIV has a strong tropism for CD4+ cells so provirus integration within egg and sperm cells is fairly rare but can occur preconception:

The Integrated HIV-1 Provirus in Patient Sperm Chromosome and Its Transfer into the Early Embryo by Fertilization

When it comes to perinatal HIV infection, there are many other available modes of vertical transmission: breastfeeding, placenta, etc.... Children that don't receive ART typically don't live past 2 years old:

Prevention of vertical transmission of HIV-1 in resource-limited settings

So this more traditional transmission method can obfuscate the origin of HIV. But even then, the risk for vertical transmission is between 15% and 45%.

All this means that there are indeed plenty of mechanisms to transmit HIV perinatally but that doesn't mean it is an absolute certainty .

If anyone is interested in infectious disease news: r/ID_News

With no context, no one can really answer this question without just referring you to a textbook.

Immune systems are not "strong" in the sense of a muscle. Good immunity is a balanced response to appropriate stimulation. Any over-response typically either results in morbidity, e.g. eczema, Crohn's, or mortality, e.g. cytokine storm.

It's thought Delta evolved within an immunocompromised person(s) and Omicron was likely a spillover from humans to mice and back to humans.

https://www.nejm.org/doi/full/10.1056/NEJMsb2104756

https://www.sciencedirect.com/science/article/pii/S1673852721003738

It's also good to remember that coronaviruses aren't just some singular static thing. SARS-CoV-2, for instance, is highly mutable. So a better question would be variant competition because as far as viral species go, you can definitely be co-infected.

During the pandemic, yes, SARS-CoV-2 had much higher incidence:

https://coronavirus.jhu.edu/testing/individual-states

But the normally circulating coronaviruses as we call them are definitely still around and currently making their annual peak right now:

https://www.cdc.gov/surveillance/nrevss/coronavirus/natl-trends.html

The usual disclaimer of course that many viruses make up the "common cold".

In case anyone likes infectious disease news: r/ID_News

It's good to remember that vaccination coverage is just as important as efficacy.