Thread: COVID-19
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Old 03-27-2020, 11:03 AM
BlackPhillip BlackPhillip is offline
Join Date: Jan 2019
Posts: 1,758

Here's an article I read back in the day that gives some background of infectious diseases. Interesting reread now.

Assessing the Epidemic Potential of RNA and DNA Viruses
Emerging Infectious Diseases - December 2016

Spoiler - excerpts from abstract:
A series of recent emerging infectious disease outbreaks, including the 2014 Ebola virus disease (EVD) epidemic in West Africa and the continuing Zika virus disease epidemic in the Americas, have underlined the need for better understanding of which kinds of pathogens are most likely to emerge and cause disease in human populations. Many, although not all, emerging infectious diseases are caused by viruses, and these frequently emerge from nonhuman host reservoirs (1–3). The enormous diversity (4) and high rates of evolution (5) of viral pathogens discourage attempts to predict with any precision which ones are most likely to emerge in humans. However, there is some consensus, at least in general terms, regarding the kinds of traits that are most essential in determining the capacity of a virus to infect, cause disease, and spread within human populations (Table 1). We focus on one of these traits, the capacity of a virus to spread from one human to another (by any transmission route other than deliberate laboratory exposure), a key determinant of the epidemic potential of a virus.
Pathogen pyramid for RNA and DNA viruses. link to figure 1
- Level 1 indicates viruses to which humans are exposed but which do not infect humans.
- Level 2 indicates viruses that can infect humans but are not transmitted from humans.
- Level 3 indicates viruses that can infect and be transmitted from humans but are restricted to self-limiting outbreaks.
- Level 4 indicates viruses that are capable of epidemic spread in human populations.

Even when a virus is capable of transmission between humans, the critical threshold R0>1 is not always achieved. However, because changes in virus traits or host population characteristics can influence R0, level 3 viruses (Table 2) are of special interest from a public health perspective, and of special concern when, like MERS-CoV, they also cause severe illness. Demonstrating human transmissibility is often difficult, but essential. The best evidence is likely to come from virus genome sequencing studies. These studies should be a public health priority (40).

We currently have few clues to help us predict which mammalian or avian viruses might pose a threat to humans and, especially, which might be transmissible between humans. One argument in favor of experimental studies of these traits, including controversial gain of function experiments (30), is that they could help guide molecular surveillance for high-risk virus lineages in nonhuman reservoirs.

The first line of defense against emerging viruses is effective surveillance (40). A better understanding of which kinds of viruses in which circumstances pose the greatest risk to human health would enable evidence-based targeting of surveillance efforts, which would reduce costs and increase probable effectiveness of this endeavor.
They need to update Table 2 for the coronovirus promotion. Table 2 = Viruses (n = 37) that are known or suspected of being transmissible (directly or indirectly) between humans but to date have been restricted to short transmission chains or self-limiting outbreaks

Last edited by BlackPhillip; 03-27-2020 at 11:37 AM..
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